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Field Device Web Server Release 1.0 Software User Manual

1. 3 50 3 3 6 T Description dere er eet 3 50 3 3 6 2 InputS E exu pee REN AE 3 50 3363 Outputs A ed ee OR BO Re 3 50 3 3 6 4 Fault messages ey oh ee 3 50 3 3 7 Procedure void add cgi par unsigned char par type url val value 3 51 3 3 7 T Description Ge ed oe eee 3 51 Inputs eden Recte eme ux ete S n en Glee ne denas 3 51 IIKI OUMU ar ARM C C e Mr E 3 51 3 3 7 4 Fault messages and failure modes 3 51 3 3 8 Function char decode url str char inpstr 3 51 3 3 8 L DeSCrIpUO e cerei rte 3 51 3 3 8 27 nte Re an EE SE uec REY ve OS 3 51 83383 Outputs oce eee gite on toe qe e ge RU a INE Nee core UI Re n dcn 3 51 3 3 8 4 Fault Messages 4 Ie Obie 3 51 3 3 9 Function tdata base struct search object void 3 52 3 3 0 1 Descriptions inscr aee e rS e DER NOR Gs 3 52 33 02 esses RIS Od ele to UU n DEREN DEO MER ORE 3 52 3 919 33 BY ced ee he tik scr UR ie aedem hh be ie 3 52 3 3 0 4 Fault Messages eG BRT Re ae hye ea URNA E Eee gg 3 52 3 3 10 Function tdata base struct _ 1
2. 3 52 3 3 10 1 Description eed 3 52 3 3 10 2 IN Puts is 3 52 33103 Guiputtttt 3 52 3 3 10 4 Fault messages Re RES e err hr ae 3 52 34 JMedulebasicencoder eec pe Ee ex eire re eene s 3 53 3 41 Function int getkey char 2 3 53 Description ye oA RU m 3 53 3 4 12 Inputs OEC RSEN NEU Meg P dene 3 53 3 4 1 3 O tputs eec BEE GALE Oo ES PR op be bie eine ae E MEW ERTS Y 3 53 IAA Fault Messages eco Ie b eor Mens en ee TO DU uie SE Urn 3 53 3 4 3 Function unsigned short decode_four unsigned char inpbuf 4 char outstr unsigned 3 54 3 4 2 T Description eens bee de tga ied Be b B P 3 54 2 4 22 Inputs iie E vale cas bla EC e En e e wee dela 3 54 SAD Se FOUUPUIS al 3 54 3 4 2 4 Fault messages eee E Kies x WE Le ae DT ae 3 54 4 PACKAGE HTML GENERATION 3 55 4 1 Module html page elements 3 57 4 1 1 Definition of thtml page elements data type 3 57 Page 14 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Contents 4 1 2 Function thtml page elements Makehtml_page_elemen
3. 3 73 4 4 1 1 Description nem re 3 73 74 12 Inputs 4 meme Sed ES RE edie 3 73 44253 Outputs 4 Red ET AERA HE eda 3 73 4 4 1 4 Fault messages Cert eel Buyer ease 3 73 APPENDIX A HTTP PROTOCOL SPECIFICATION FOR FIELD DEVICE WEB SERVER l CONTEXT FREE GRAMMAR OF HTTP REQUEST A 1 2 LEXICAL GRAMMAR OF TOKENS OF HTTP REQUEST A 9 ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 15 Contents APPENDIX CONFIGURATION OF REPOSITORY OF VIRTUAL FILE SYSTEM APPENDIX EMBEDDING HTML PAGES IMAGES AND APPLETS APPENDIX D SERVING DYNAMIC HTML 1 SKELETON BASED DYNAMIC PAGES D 1 2 ON LINE GENERATION OF PAGES D 4 Page 16 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Figures Figure 1 1 Place of field devices in automation system 1 1 Figure 1 2 Three tier architecture of INTERNET client server application 1 2 Figure 1 3 Architecture of INTERNET based application in an Alspa F8000 equipment 1 5 Figure 1 4 General architecture of Field Device Web Server software 1 6 Figure 2 1 Developme
4. DES AERA eee galas 3 29 2 2 3 Procedure unsigned short generic_sendback_routine int socket 10 3 29 2 231 IRE CDU ED d 3 29 ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 11 Contents 2 3 Page 12 2 2 3 2 3 29 oerte qne Up ETE Rn pr E Uem DS 3 29 2 2 3 4 Operational processing 3 29 2 2 3 5 Fault imessdges aed edi e BOREAM SEN tee Pas AUR 3 29 2 2 4 Procedure unsigned short generic_error_report int socket id 3 29 2 241 Description i eer oen eat tad 3 29 252 Inp te ree tea EO CS Ma Oud edle die feno Ree rts 3 29 22 43 OUUTE x esee xr nee Re er ee haps KOE ec ee ip 3 29 2 2 4 4 Operational processing 3 30 2 2 4 5 Paultinessages le chop 3 30 2 2 5 Procedure int typed_server_prompt int socket id char res type 3 30 2 251 Description coetu ERE SUN ee eae 3 30 2 255 25 3 30 222537 Outputs V 4 fa ONG ak da d M E dep m ads 3 30 2 2 5 4 Operational processing 3 30 2 2 5 5 Fault Messages ict cane bay dal wee Oba ab 3 30 Module
5. Contents CHAPTER 1 PRESENTATION 1 GENERAL DESCRIPTION OF DEVELOPED 5 14 CHAPTER 2 GENERAL INFORMATION 1 UTILISATION CONTEXT ehe 2 1 2 R LE OF COCKTAIL TOOLBOX 2 4 START UP STOP FUNCTIONS 2 5 3 1 Start up procedure 1 2 5 3 2 Stop procedure de egre tere ee ee eee 2 5 CHAPTER 3 USE I PACKAGE VFS GENERATION 3 1 11 Module Commondef 3 2 111 Function char init char const char 1 3 3 2D SCFIDUOR usce n Rem 3 3 12154522 Inputs 452i ences te 3 3 11 137 8 series ven PORUM RUN SAP S 3 3 1 1 1 4 Fault messages eee m e ath Rc Re s 3 3 1 1 2 Procedure void close char char 1 3 3 L12 T Descriptions 3 3 121202 SUN PUSS e tare Du ae 3 3 QUE US 6 3 3 112 4 Fault messages 2255 ce bp 6 3 3 1 2 Module data base structure 3 4 1 2 1 Definition of tdata base structure data type 3 4 1 2 2 Functio
6. T Berners Lee R Fielding H Frystyk Hypertext Transfer Protocol HTTP 1 0 Network Working Group RFC 1945 10 4 WEWELCOME YOUR COMMENTS AND SUGGESTIONS ALSTOM strives to produce quality technical documentation Please take the time to fill in and return the Reader s Comments page if you have any remarks or suggestions ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 5 Preface Page 6 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Reader s comments ALS 53424 a en Field Device Web Server Release 1 0 Software User Manual Your main job is L System designer L Programmer L Distributor E Maintenance L System integrator L Operator Installer Other specify below If you would like a personal reply please fill in your name and address below COMPANY pate NAME Die ae WR ADDRESS 6 Send this form directly to your ALSTOM sales representative or to this address ALSTOM Technology Technical Documentation Department TDD 5 avenue Newton BP 215 92142 Clamart Cedex France Fax 33 0 1 46 29 12 44 comments will be considered by qualified personnel REMARKS Continue on back if necessary ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 7 Reader s comments Page 8 Field Device Web Server Release 1 0 Software User Manual ALS 53424
7. 0 D 2 Figure D 2 Skeleton of the page from the example D 2 Figure D 3 Part of Figure D 1 program D 3 Figure D 4 Example of abstract representation procedure D 4 Figure D 5 Example of HtmlPageToString routine D 5 ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 17 Tables Table 3 1 Type values and their 3 5 Table 3 2 Non Abstract objects attributes 1 3 6 Table 3 2 Non Abstract objects attributes continued 3 7 Table 3 3 Server loop phase corresponding routine and module 3 24 Table 3 4 Relationship between the first and second field values 3 38 Table 3 5 Compatibility of the record type and the routine parameter 3 39 Table 3 6 Environment data structures 1 3 46 Table 3 7 Common types of option 146 3 47 Table 3 8 Symbolic name corresponding to the value of the first field 3 58 Table 3 9 Description of non a
8. point EN sign ese commentchar N10 M13 0 NULLCHAR 30 hex digit elie gale 9 ces ine 00 2 Page 10 d n TokenPtr Field Device Web Server Release 1 0 Software User Manual illegal character xxWarning Attribute Position xxCharacter ALS 53424 HTTP protocol specification for Field Device Web Server START option optstring ending RULES STD GET Attribute ORDER Value httpGET return ORDER STD POST Attribute ORDER Value httpPOST return ORDER STD slash return SLASH STD point return POINT STD HTTP ge are 8 STD sign nr Attribute NUMBER Value long atol TokenPtr return NUMBER STD ELST Attribute FLOAT Value float atof TokenPtr return FLOAT STD id Attribute IDENT Ident char AllocTokenStr TokenLength GetWord Attribute IDENT Ident return IDENT STD optstring option NULLCHAR STD amp return SEP STD return ASSIGN STD return URLSEP STD recuse 5 STD return 2 2 STD B Eee UU SU p yj STD er vee foptstring puro alar a opt remy foptstring comment char Attribute RECUP String
9. ce Se tee AO RE 3 11 1 3 5 4 Fault messages Oh EN RC ge 3 11 Procedure void AppendNode tdata_base_struct root tdata base struct 3 12 1 26 5 Description uico ERE RE EUR eL RR EU PIER EE 3 12 1 3 6 2 Inputs 4E pIRA 3 12 1 3 6 3 wee bees ep ides 3 12 1 3 6 4 Fault Messages EN oa beg 3 12 Function tdata_base_struct FindNode tdata_base_struct root tdata_base_struct path pchar user pchar password visse een Ee e a er eR ed vale ees 3 13 1 377 T oe cueste 3 13 1 3 7 27 Inputs eet Y e e Rer e ex RU ac IE ce dia 3 13 1 3 7 3 QuUtputS Sg eee ced ee ge cata dae NIG Sect ate acess eee 3 13 1 374 Fault messages REPONIT ORI 3 13 Function tdata base struct SearchNodeInWidth tdata base struct root pchar name 3 14 1 3 8 1 Descriptions 3 14 13 62 Sele haus he Ped DAR Dew ne she tee t 3 14 1 3 8 3 SQUDPUUS re wees ais She E RO aceto 3 14 1 3 8 4 Fault wessagsfteee denies gis Seca teases oa Soar al Geese rea es 3 14 Function tdata base struct GetNodeRef tdata_base_struct root tdata_base_struct path 3 14 13 93 1 7 Descriptions tM atk eke old 3 14 1 3 9 2
10. insert_empty_lines make_html_form insert_horizontal_line insert_plain_text insert_formatted_text insert_simple_link insert_link append_rows_to_table init char close char gen tree module BuildHtmlPage BuildHtmlImage BuildHtmlTable BuildHtmlTableTitle BuildHtmlForm BuildPlainText BuildApplet BuildHtmlTableCell BuildEmptyLines BuildSeparator gt BuiledValuedInput BuildTextInput BuildImagelInput BuildButtonInput BuildCheckableInput BuildTextAreaInput InitHtmlObjectChain InitTableRow AppedRowToTable AppendObjectToPage AppedObjectToChain AppendInputToForm AppendCellToRow AppendInternalObject Figure 3 6 Module relationship within the package HTML GENERATION ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 55 The package is composed of the four following modules html page elements defines the fundamental data type thtm1 page elements which is the basis of all embedded html page constructs tree module provides the routines supporting on line generation of the embedded html page elements html gen hl completes the routines provided by the gen tree module by some higher level wrapper routines html cov module provi
11. unsigned char check flag when set to a non zero value causes the display of the button as checked checkbox pchar string of characters containing name of checkbox group pchar string of characters which gives the name of the particular element of the group check flag when set to a non zero value causes the display of the checkbox as checked string of characters containing the object s name ALS 53424 a en string of characters containing url of file which stores the image Table 3 9 Description of non abstract class attributes Field Device Web Server Release 1 0 Software User Manual Page 3 61 4 1 2 Function thtml_page_elements Makehtml_page_elements uchar Kind 4 1 2 1 Description This routine creates an object of the type specified in Table 3 9 and returns the reference to it The object is created in the system heap 4 1 2 2 Inputs The input parameter specifies the kind of the object to be created its value should correspond to one of the constants specified in the Table 3 8 4 1 2 3 Outputs The returned value is a reference of the newly created object pointer to the object if creation succeeds 4 1 2 4 Fault messages In case of failure the procedure returns the NULL pointer 4 1 3 Procedure void Releasehtml page elements thtml page elements object 4 1 3 1 Description This routine destroys the object referenced by the input parameter The heap area occupi
12. Embedded files containing passive server objects like HTML pages or more precisely page templates compressed images and bytecode of Java applets are referenced by the leaves of the skeleton tree which describes the server repository These objects should be placed in well defined server memory areas and be efficiently accessed when the request for service is received by the server engine Two methods of creation of such objects can be envisaged 1 Static the corresponding memory area is reserved and filled in at server build time the advantage of such a solution is its relative simplicity the embedding process consists in transforming the objects into corresponding data structures expressed in C and in linking these objects with the server code the disadvantage of such a solution is the rigidity of the server structure which cannot be extended at run time 2 Dynamic region reservation and filling in is done at run time of the server program the advantage of such a solution is its flexibility the files can be installed on the running server the price to pay for this feature is the increase in complexity of the server program which should support the means of loading files into memeory regions at run time e g via TFTP protocol The current version of the Field Device Web Server supports only the first method of file installation The implementation of the second method can be envisaged without major problems especially without the deg
13. object representing form component of hidden type object representing form component of submit type kreset object representing form component of reset type ktext object representing form component of one line text type ktextarea object representing form component of long text type kcheckable abstract class representing checkbox and radio button objects kcheckbox object representing a checkbox component kradio object representing a radio button component Page 3 58 kimage object representing an image embedded within an HTML form Table 3 8 Symbolic name corresponding to the value of the first field Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use In the current version of embedded HTML there exist thirty five types of objects in three groups one high level class html representing complete HTML pages high level abstract class html page object representing any type of HTML tags which can be used with an embedded page seven abstract classes representing types of HTML objects basic object separator input desc input insertable object simple input and checkable these classes of objects are used very rarely only when it is necessary to represent the common properties of other classes three classes of HTML container objects paragraph html table and html form these objects represent
14. 12 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Appendix Configuration of Repository of Virtual file B System Server customisation consists in the design and generation of the Virtual File System of the server This system is composed of three basic elements tree like data structure whose role is equivalent to the role of file system management tables Through this data structure called repository skeleton the user can find read and modify the files embedded in the host environment collection of routines which process this data structure collection of memory regions storing the embedded files The repository skeleton is implemented as a web of interrelated records linked with the help of pointers Its structure is described in the following context free grammar specified in the language of the ast processor MODULE AbstractSyntax this is a modified file uniform processing of objects is implemented TREE data_base_struct EXPORT include commondef h typedef void tscript int cleanup of character chains created in the VFS types of file nodes in VFS define define define define define define define GLOBAL c unknown 0 c text 1 2 c jpeg 3 java 4 15 e seriat 6 define yyALLOC s1 s2 tdata base struct Alloc s2 ALS 53424 Field Device Web Server Release 1 0
15. 3 14 1 3 9 3 Qutputsc SALE TON OA ORE CET eU ees aide esso 3 14 1 3 9 4 FaultneSsages e e tree e er red d eoe 3 14 Procedure void ProcessNode tdata base struct node tnameproc proc 3 15 1 3 10 T Description 6 3 15 1 3 10 2 Inputs eR enr ete oak RUE EE 6 3 15 1 3 10 3 Outputs ope 3 15 T 3 10 4 Fault messages m RH p E MOORE P ERES 3 15 Function pchar InstallFileContent tdata base struct root tdata base struct path pchar contents unsigned short length 3 15 1532111 Description Parse E PPP E 3 15 1 3 11 2 Inputs c cae eee e e eC PUE THER E 3 15 1 3 11 3 OUIpUlS e REIN dace eee tats doe fes Ae nice 3 15 T 3 11 4 Fault messages c sese tr mene rm ER RR ER eR EE ELO ei a 3 16 Procedure void InstallAuthorisation tdata base struct realm pchar username pchar passwotd oe even e Ratte 3 16 1 3 12 1 Description tke LESER ODE IST DES 3 16 LB AD Den puts vecina ee Th 3 16 13 1233 Qutputs 1er Sesh thet ONE ERI M Sea EX dA 3 16 13124 Fault messages eene et en hd ene a ee 3 16 Function tdata base struct AppendStep tdata base struct path pchar name 3 16 13 13 1 Description uen Aa
16. E RIO Ue oe Bees 3 18 1 3 17 2 Inputs EEE woes Uer EE dala 3 18 1 3 17 3 Outputs eso Pe Gis Oe bs LAER etr tees de ape eara 3 18 1 3 17 4 Fault messages v REOR oe AA Ee Qu Renee n eme 3 18 1 3 18 Procedure void PrintNode tdata base struct 3 19 1 3 18 1 Descriptions eure E E ROREM Ed so A 3 19 1 3 18 2 Inputs 6 3 19 1 3 18 3 Outputs aoe oes Oe Ere Das de Een a nra ome e deg eee aS 3 19 1 3 18 4 Fault messages o ated ERE amg cea RR QUU 3 19 1 3 19 Procedure void PrintRepository tdata base struct root 3 20 1 3 19 1 Description serrer 6 3 20 1 3 19 2 Inputs S A T E 3 20 1 34 9 3 OUMU c caue ER exe gre YET e EIER o e ORI EDS AS 3 20 1 3 19 4 Fault messages 1 3 20 2 PACKAGE SERVER ENGINE ahh hh hh re 3 21 2 l Module Servengine i408 oe eed oe de eb o eR e RAT RS 3 22 2 1 1 Procedure void server loop unsigned short nr tcallback analyse routine ref tcallback response routine ref tcallback error report ref tcallback cleanup routine ref 3 23 D SCrIptO Jaco erui cue feu RS irc a Du 3 23 2112 I
17. RR CHF OPER ede EE MEUSE CHE e Spe 3 34 DES A 3 COUEDUES d doesnt aee tete Wt elec rrr ta reete nte uh re a 3 34 29 44 Fault messages esce Tute ee te De de 5 3 34 2 3 5 Procedure int sockprintf int sock 0 3 34 2 3 5 te 6 D SCTIDUODB e to eaedem men Ata dee 3 34 2 352 Inputs ates RE 66 3 34 2 3 5 3 OUPS penae o TEE 3 34 2 3 5 4 Operational processing 2 3 34 23855 Fault esssgee ities EROR ER De 3 34 2 3 6 Procedure int vsockbinsend int sock_id char string unsigned short length 3 35 2 3 6 T Descriptio vesc ostesur ex uev Oe ues Erbe Ue e dede 3 35 2 3 6 2 Inputs A E ENS ae ead oe 3 35 2 3 6 3 Outputs 3 5 ee aS Wei epe ee OS a 3 35 2 3 6 4 Fault messages Cag ated ev genes ey HE PUE OE ree 3 35 2 3 7 Procedure int sockreadf int sock id char buffer int size 3 35 223721 gt 66 3 35 2 3 1 2 Inputs s e mee 66 3 35 EF 3 35 2374 Fault messages eese ee Res sad pO ev vx Ee EY vea mede Yd 3 35 2 3 8 Procedure void peeraddrstr char buffer 3 36 222287 Description e hen OU ERIS UR 3 36 2 3 0 2 Inputs 3 3
18. pchar name 1 3 13 1 Description This function is used for the successive construction of path objects The object stores the access track which leads from a tree root to a node within this tree The function implements add the step named by the second parameter to the path referenced by the first parameter 1 3 13 2 Inputs The function has two inputs path path object which localises the node within the VFS tree if this pointer is equal to NULL the operation has no effect and the function returns NULL name pointer to the string which contains the name of the step to be appended to the path 1 3 13 3 Outputs The function returns the reference of the newly created object having the new step appended to the one provided by the first parameter Page 3 16 Field Device Web Server Release 1 0 Software User Manual ALS 53424 1 3 13 4 Fault messages If the function fails to append the new step NULL pointer is returned No explicit textual message is generated 1 3 14 Function pchar RecoverResName tdata_base_struct path 1 3 14 1 Description This function used in the process of constructing request environment variables recovers the last step of the path object passed by the input parameter and considers it as the resource name i e the name of a VFS node to which the HTTP request in which the path was included applies 1 3 14 2 Inputs This function has a single input which contains the reference to
19. pchar target target for displaying the object referenced by ref attribute unsigned char isref flag which when set signifies that the object is a hyperlink and when reset means that the object is an anchor Table 3 13 Description of the attribute section for the six first group routines ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 67 4 2 2 3 Outputs All the routines from the group return a reference to an object of the thtm1 page elements type The result is normally the pointer to the page with the appended object 4 2 2 4 Fault messages No fault message is generated If the operation programmed by the routine fails it returns a NULL pointer Page 3 68 Field Device Web Server Release 1 0 Software User Manual ALS 53424 4 3 Module gen_tree_module This module contains the routines which realise two types of functions creation of HTML related objects extension and modification of HTML related objects They are described in the following sections 4 31 Routines which generate HTML related objects The routines from this group are specialised in generation of an object of a given type Usually the name of the routine is significant and tells which type of object the routine creates The following list introduces the routines and their signatures i e the list of parameter types between brackets BuildHtmlPage pchar pchar pchar unsigned char pchar th
20. 2 3 3 1 Description This routine provides the platform independent interface to the accept operation on the primary socket followed by retrieval of the remote peer address 2 3 3 2 Inputs The only input parameter is the identifier of the primary server socket which waits for the requests for connections 2 3 3 3 Outputs The routine returns either the identifier of a secondary socket created as the result of connection request acceptance or an error code 2 3 3 4 Operational processing The control flow of the routine makes use of a blocking call to the accept primitive to stop the main server loop while waiting for the connection request from the remote client Connection acceptance is followed by the creation of a secondary socket The identifier of this socket returned by the call to accept is then held to be returned further on as the routine result Failure of the call to accept which gives the negative or zero result makes the routine return immediately The success of the accept call provides the retrieval of the remote peer address to a local data structure This address can be retrieved by the call to the peername routine 2 3 3 5 Fault messages None ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 33 Use 2 3 4 Procedure int closestream int sock id 2 3 4 1 Description This routine is a wrapper of the operation when closing the socket 2 3 4 2 Inputs The only input
21. char AllocTokenStr TokenLength GetWord Attribute RECUP String RECUP i J option id g GetUpper OptBuffer Attribute OPTION Value RecoverOption OptBuffer return OPTION ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 11 HTTP protocol specification for Field Device Web Server foption foption cr lf yyStart ending return END MAIN ending sign nr Attribute NUMBER Value long atol TokenPtr TestTokensInEnding EntitySize EntitySize TokenLength return NUMBER ending flstr Attribute FLOAT Value float atof TokenPtr TestTokensInEnding EntitySize EntitySize TokenLength return FLOAT ending xd r putes DENT dent char AllocTokenStr TokenLength GetWord Attribute IDENT Ident TestTokensInEnding EntitySize EntitySize TokenLength return IDENT ending amp fe d W TestIekeusrmsndcngi yg 7 EntitySize EntitySize TokenLength return SEP ending fed TestlokensinEnding EntitySize EntitySize TokenLength return ASSIGN ending NULLCHAR if EntitySize 0 return EofToken ending pr lr 2 7 pr ince AD TALS POINT THE ENTITY 15r SO Entitysrcese if EntitySize 0 return EofToken Figure A 2 Lexical specifications of Scanner module Page
22. images applets will be performed by the routine whose address is passed via the external variable send_page_routine If this value corresponds to the entry point of a user provided routine it will be used to control the response generation 2 identification of type of object to service The second step of the routine consists in identifying the type of object i e verifying whether the requested action consists in activating a script sending a passive object or requesting a directory listing The outcome of this choice activates an appropriate processor routine 3 object search and identification of action to be executed In the third phase the requested object is searched for If it is not found an error page is selected and prepared for delivery to the client If the object is found and is not submitted to access authentification the previously chosen processor is activated If the object is submitted to access authentification the challenge procedure is started by selection of an appropriate response PDU At the end the selected action is executed and its result is returned as the result of the routine Figure 3 4 Flow diagram of the response composing routine Page 3 28 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 2 2 2 5 Fault messages In the case of failure of the last step of the routine s algorithm an error message can be sent as a special value of the return code This message
23. username pchar userpass pchar LC server root tdata base struct cgi bin tdata base struct cgi __params tegi par EntitySize int clean_ init_env print env add cg par extract auth decode url str AllocToken FreeToken search object search script Use Source OpenSource GetLine CloseSource Scanner BeginFile CloseFile BeginScanner CloseScanner GetToken Parser http process BeginParser 0 lt ParseFromSocket InitParsing EndParsing Figure 3 5 Module relationships within the package HTTP Analysis This package is designed in order to provide the support for the analysis of incoming request PDUs It is composed of six modules http process Parser provides the convenient wrap up of PDU analysers implements the routine analysing the syntax of incoming PDUs this module is constructed with the help of processors from the Cocktail toolbox 5 Scanner implements the routines which co operate with the syntax analysers the module is constructed with the help of processors from the Cocktail toolbox 5 Source implements the interface between the network and the syntax analyser the interface of this module is inherited from the Cocktail
24. 4 3 Procedure int set_db_data char name unsigned char val type void value 2 4 3 1 Description The role of this routine consists in modifying the data value which corresponds to the identification key 2 4 3 2 Inputs The routine has three input parameters datakey string of printable characters identifying the data record to be modified valuetype integer of unsigned char type determining the type of data modified datavalue pointer to anonymous type void conveying the data to be set into the record 2 4 3 3 Outputs The routine returns the value which identifies the result of the data record modification If the modification is successful the routine returns the type equal to its second parameter In the opposite case the returned value is 1 2 4 3 4 Operational processing The first phase of the routine s algorithm consists in searching a record identified by the key passed by the routine s first parameter If the search process succeeds the value type of the found record is tested If the type of the found record is compatible with the type specified by the second parameter of the routine the new data value is set The value transferred to the data record corresponds to the value referenced by the third input parameter of the routine If the types are not compatible the data is not set and the routine returns the 1 value In the case of successful value transfer the routine returns the value correspondin
25. BuildSeparator BuiledValuedInput BuildTextInput BuildImagelInput BuildButtonInput BuildCheckableInput BuildCheckableInput BuildTextAreaInput unsigned char unsigned char nb of empty lines represented by the object width of the line in unsigned char thickness of the line in pixels pchar unsigned char alignment code for the line this parameter indicates the kind of object it can take only predefined values which are khidden ksubmit or kreset name pchar character string which contains the input identifier init value name pchar pchar value given to the object semantics of this parameter vary from one type of object to another character string which contains the input identifier value pchar text which is initially displayed in the input size unsigned char height of the input in pixels maxlength name unsigned char length of the input given in number of characters character string which contains the input identifier source name path to the virtual file which contains the image contents character string which contains the button identifier value character string which contains the text which is to be displayed on the button onClick unsigned char character string which contains the name of the script activated when the button is clicked this parameter indicates the kind of object it can take on only pr
26. Server Release 1 0 Software User Manual Page C 1 Embedding HTML Pages Images and Applets Page 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Appendix Serving dynamic HTML D The packages of the Field Device Web Server provide two methods to generate pages whose context depends on the data retrieved from the basic application called in the sequel dynamic pages The first of them concerns the pages which have only a few variable elements placed within a large body of invariant data The second concerns genuinely dynamic pages containing many variable components the parameters of which vary frequently in time 1 SKELETON BASED DYNAMIC PAGES The first type of page should be structured into two components page skeleton page invariant frame which can easily be edited using standard tools like MS Front Page this part of the page can represent either the informative part of the page or the basic components of the interactive part of the page variable components page elements which change page aspect font colours parts of text references to images type of interactive controls applet parameters etc or can change browser behaviour while processing the page parameters of page header applet parameters hyperlink contents etc variable components are represented by format expressions in C language s for strings d for integers etc The process of placing variable component
27. a path kind object 1 3 14 3 Outputs The function returns the pointer to the storage area in which the name of the last step of the path is stored 1 3 14 4 Fault messages When the NULL pointer is provided as the parameter the function returns NULL No explicit textual message is generated 1 3 15 Function pchar PathToString tdata_base_struct path 1 3 15 1 Description This function is used mostly for debugging purposes It converts the path object referenced by the first parameter to a printable character string which has the following syntax step1_name step2_name step_name stepn_name 1 3 15 2 Inputs The unique input of the function contains the reference of the path object 1 3 15 3 Outputs The function returns the pointer to the character string allocated in the system heap which contains the printable representation of the path 1 3 15 4 Fault messages The NULL pointer is returned if the reference of the path object is NULL No explicit textual message is generated ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 17 1 3 16 Function tdata_base_struct StringToPath pchar pathstring 1 3 16 1 Description This function provides the operation which is the reverse of the function PathToString It converts the printable representation of the path to the path object 1 3 16 2 Inputs The unique parameter of the function is a pointer to the character string The co
28. an appropriate kind no operation is performed 1 3 5 3 Outputs None 1 3 5 4 Fault messages None ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 11 1 3 6 Procedure void AppendNode tdata_base_struct root tdata_base_struct node 1 3 6 1 Description This routine adds the VFS node referenced by the second parameter to the VFS tree the root of which is referenced by the first parameter 1 3 6 2 Inputs The two procedure inputs are root pointer to an existing root node of a VFS tree repository if this pointer is equal to NULL no operation is performed node pointer referencing an existing VFS node which can be of an embedded_file an embedded_script or an embedded_directory kind if the pointer does not point to a node of an appropriate kind no operation is performed 1 3 6 3 Outputs None 1 3 6 4 Fault messages None Page 3 12 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 1 3 7 Function tdata_base_struct FindNode tdata_base_struct root tdata base struct path pchar user pchar password 1 3 7 1 Description The role of the routine consists in finding the node referenced by the object of the path kind second parameter of the routine in a VFS tree referenced by its root first parameter of the routine The process follows naturally the path object structure which is composed of a list of names of intermedi
29. chapter 3 1 it is worth noting that non trivial sites can be tedious and complicated but can be easily mechanised by using a configuration tool see Appendix B embedded look and feel objects which are data structures representing embedded passive objects page frames applets images these data are represented as octet arrays residing in memory regions accessible via VFS in the normal development process these objects are designed and implemented by tools adapted to the object nature HTML editors image editors JAVA development tools a necessary step concerning the transformation of standard formats of their representations ASCII files GIF JPEG files byte code to byte arrays loadable to device memories is to be supported by appropriate tools see Appendix B page composing routines which allow the user to merge passive objects page frames with application data in order to form a complete HTML pages which incorporate application status these routines are to be programmed manually or are to be generated from a user friendly notation see Appendix C routines representing active server objects CGI scripts dynamic pages executed on requests received from the client these routines serve to integrate application data to server pages the routines reuse generic functions provided by HTTP reuse their design is so dependent on the application that only manual development process is possible The development process of the specific ap
30. control applications from one system to another The idea which initiated launching of the development process of the Field Device Web Server had its origins in the analysis of INTERNET structure This world wide communication support is one example of a successful application of the interoperability principle applied to diverse software products The interoperability of INTERNET products clients and servers is based on universally accepted standards which are the TCP IP protocol for reliable data transport the HTTP protocol for application information exchange the HTML format for information structuring and presentation Application Client j Server Application tier tier Figure 1 2 Three tier architecture of INTERNET client server application Page 1 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Presentation INTERNET distributed applications are based on the principle of a three tier architecture Figure 1 2 which makes use of universal client and server frameworks independent of the nature of data processed on condition that the data exchanged over the network are transported via the HTTP protocol and are structured according to the HTML format The three tier architecture standardises basic services of the client and server parts of the application In this configuration the client part is totally independent of the application so called thin client The burden of ap
31. esi dae brs tae oop Der I ge iba eles 3 16 D3215 2 3 16 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Contents 1 3 13 3 Outputs esse oS 3 16 1 3 13 4 Fault messages rep n pr rmm 3 17 1 3 14 Function pchar RecoverResName tdata base struct path 3 17 1 314 doe 3 17 1 3 14 2 Inputs RI SEE RN MERI ahead ee I a 3 17 1 3 14 3 Outputs eer 3 17 123 144 Fault messages 3 17 1 3 15 Function pchar PathToString tdata_base_struct path 3 17 1 3 15 1 Description nr ee e S peer en ere ed 3 17 1 3 15 2 Inputs 42 See ERRORES ERO YA Deadly dA Eee s 3 17 1 3 15 3 Outputs ceste tee 3 17 1 3 15 4 Fault messages esee ev ete aE na SEPA E ONES 3 17 1 3 16 Function tdata base struct StringToPath pchar pathstring 3 18 1 31621 Description sae tek AE 3 18 1 3 16 2 AM puts Secs rc RR ES Ca dew es S 3 18 1 3 16 3 Outputs oi osc cee pres P Oa ng IPIS Ex IU ROTE 3 18 1 3 16 4 Fault messages 3 18 1 3 17 Procedure void PrintPath tdata base struct path 3 18 1371 Description Re agen ee
32. has three inputs which are port nr unsigned char type integer signifying the TCP UDP port number to which the socket is linked type pointer to character chain holding the protocol designation it should be either t cp or udp quelen integer number signifying the queue length reserved for buffering the incoming connection requests 2 3 2 3 Outputs The value returned by the routine is either the identifier of the socket bound to the chosen address and ready to accept the connections or an error condition code which identifies the eason for incorrect network operation The socket identifier returned from the routine is always positive The negative result always means a malfunction 2 3 2 4 Operational processing The routine calls the operations on sockets in the following order 1 Socket creation of a given type the socket type can be either SOCK_DGRM SOCK STREAM the first type is created when the second routine s parameter contains the string In any other case the socket created is of the SOCK STREAM i e TCP type If socket creation fails the routine exits with an error code which is anon positive value An error message accompanies this failure detection 2 Once the creation of the socket succeeds one attempts to bind it to a network address this operation makes a call to the bind primitive the part of the address relative to the IP of the network is taken from the platform
33. id char buffer int buffsize this routine fills in the buffer provided by the analysers with the characters provided by the input stream the function is called deep inside the Scanner s structure and all its three input parameters have meaning only in the calling context of the Scanner module the user only has the possibility of indirectly choosing buffer size third parameter 3 2 2 Module Scanner This module is automatically derived from a formal specification by the use of the Rex processor 6 The role of the Scanner consists in assembling the sequences of characters taken from the input stream into a series of tokens higher level entities which are used by the Parser The Scanner specification is done in an appropriate language which describes token structure in terms of regular expressions The equivalent compilable files in C language are produced automatically by Rex The exported interface is relatively complicated its role consists in supporting three phases of analysis operations initialisation parsing and termination None of the interface elements are called directly by the user The exhaustive description of the interface is provided in 6 ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 45 Use 3 2 3 Module Parser This module is automatically derived from a formal specification by the use of the Lark processor 7 The Parser module is the driving engine of the process of incoming
34. is produced by the routine which writes the response PDU to the network and is inherited from the module implementing socket interface to TCP IP In the majority of cases a negative or null value corresponds to a transmission failure 2 2 3 Procedure unsigned short generic_sendback_routine int socket_id 2 2 3 1 Description This routine serves as a wrapper to the previously described response_composer routine which is invoked with the second and third parameters set to NULL By choosing these parameter values the routine forces the operation mode for the invoked response_composer processor in which the choice of the object servicing routine is mode via two pointers send_script_routine and send_page_routine see 2 2 1 This routine is proposed a priori as an implementation choice for the response composition phase in the server s basic loop see 2 1 2 2 2 3 2 Inputs The only input parameter of the routine corresponds to the identifier of the socket on which the connection with the client is established This parameter is passed over to the wrapped response composer routine 2 2 3 3 Outputs The routine returns the value which is returned from the wrapped response composer routine For the meaning of the returned values refer to 2 2 2 3 2 2 3 4 Operational processing Routine processing is limited to the invocation of the response composer routine with the second and third parameters set to NULL 2 2 3 5 Fault messag
35. is used to qualify response composer input parameters These six items provide an interface which allows the user to organise the mechanisms of object handling by the embedded server 2 2 1 Variables exported by the module The two variables send script routine and send page routine are defined as follows int send script routine int tdata base struct int send page routine int tdata base struct They are references of the routines which will be used by the server loop to implement the two mains operations response to requests of cgi script execution send script routine response to requests for sending internal server objects pages images and applets send_script_routine The user is expected to provide via these variables the addresses of the routines specially designed for its application By default the variables are set to NULL They are expected to receive the appropriate values during the initialisation phase of the server loop If the initialisation is not done properly the server will systematically answer any client request by sending a standard error response described in the following section Page 3 26 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 2 2 2 Procedure int response composer int socket id tprocessor scrproc tprocessor pproc tprocessor dproc 2 2 2 1 Description This routine implements the basic elements of the process ruling the composition of r
36. of heap space fails the routine returns a NULL pointer 3 3 22 Procedure void FreeTokenStr char tokenstr 3 32 1 Description The routine frees the heap frame occupied by the string allocated by the AllocTokenStr routine 3 3 2 2 Inputs Pointer to the heap frame to be freed 3 3 2 3 Outputs None 3 3 2 4 Fault messages None Page 3 48 Field Device Web Server Release 1 0 Software User Manual ALS 53424 3 3 3 Procedure void clean_env void 3 3 3 1 Description This routine empties all the significant environment variables as follows The heap space occupied by the strings stored in the environment table elements is freed and table elements are set to NULL The content of the cgi_params table is emptied space freed and elements set to NULL username and userpass strings are freed and set to NULL path object is released and its reference set to NULL EntitiySize variable is set to 0 resource category is set to c unknown 3 3 3 2 Inputs None 3 3 3 3 Outputs None 3 3 3 4 Fault messages None 3 3 4 Procedure void init env void 3 3 4 1 Description Simplified version of the routine clean env which set the environment variables to default values without freeing the heap frames This procedure is used mostly in the first phase of server operation 3 3 4 2 Inputs None 3 3 4 3 Outputs None 3 3 4 4 Fault messages None ALS 53424 Field Device
37. of the routine is the identifier of the socket to be closed 2 3 4 3 Outputs The routine transfers the result of the call of the closesocket operation 2 3 4 4 Fault messages None 2 3 5 Procedure int sockprintf int sock id char xtempl 2 3 5 1 Description This routine is used to send a block of characters to the network via a secondary socket The transfer mode resembles formatted write of a list of items to a file 2 3 5 2 Inputs The number of inputs to this routine can vary There are at least two inputs sock id socket identifier xtempl character string which is constructed according to rules set for the format specification in the printf fprints sprintf etc routines The routine can optionally have a set of inputs corresponding semantically to the items constructing the format string 2 3 5 3 Outputs The output from the procedure provides the result of the transmission attempt It gives either a number of characters written to the socket or an error code resulting from the operation 2 3 5 4 Operational processing The operation of the procedure progresses in many steps In the first step the format second input and the list of free parameters all the starting parameters remaining from the third input are used to generate a string which is stored in an internal buffer It is important to know that the result of this operation is a string having less than a fixed number of characters in
38. page elements list of objects included in the title table cell align pchar character string containing alignment style width unsigned char relative cell width in 96 colspan unsigned char horizontal cell span in number of columns rowspan unsigned char vertical cell span in number of rows objects thtml page elements list of objects contained in the cell table row objects thtml page elements list of cell objects in the row script language pchar character chain containing script language name objects thtml page elements list of plain text paragraphs contained in the script formatted text plaintext color pchar character string containing font color code size unsigned char font size in points isbold unsigned char flag set to a non zero value when font is bold isblinking unsigned char flag set to a non zero value when font is blinking style unsigned char value of to n for styles H1 to Hn objects thtml page elements pchar pointer to the list of objects contained within this object pointer to the chain of characters containing the text html image emptyline pchar character string containing url of image source file pchar character string containing the alternative string unsigned char image maximum width in pixels unsigned char image maximum heigh
39. plain text paragraphs images or separator lines They can also contain other containers a table can contain a link or a form The second group is composed of six routines whose role consists in inserting certain objects of the thtml page elements type in the html page object The functional similarity between the routines in each group allows us to give their collective concise description as provided in the following sections 4 2 1 Routines generating container objects The operations of all the routines which belong to this group are similar They consist of two successive operations 1 creation of an empty container object featuring the characteristics described by its attributes passed via routine parameters 2 filling in of the container with the collection of objects passed via routine parameters The signatures of the routines follow a regular scheme page elements routine name gt attribute params section unsigned char nr of objects One can distinguish three groups of parameters variable number of parameters lt attribute params section conveying the values of container object attributes object dependent number order and attribute type parameternr of objects conveying the number of objects to be inserted in the container one parameter n parameters represented the scheme by conveying the references of objects inserted in the container All the routines return the
40. routines 2 4 1 Procedure void init data base void 2 4 1 1 Description This routine resets the internal data store It clears all internal tables and resets all data records active before this call 2 4 1 2 Inputs None 2 4 1 3 Outputs None 2 4 1 4 Fault messages None ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 37 2 4 2 Procedure void get_db_data char name tdb_result result 2 4 2 1 Description The role of this routine consists in retrieving the data value corresponding to the identification key 2 4 2 2 Inputs The only input to the routine is the key identifying the data which is to be retrieved The key a string of printable characters is furnished via the first parameter of the routine 2 4 2 3 Outputs The output is obtained via the second parameter This parameter is a pointer which should reference an existing structure of the tdb_resul type The structure is composed of two fields result and value The first field indicates the kind of response obtained It can take the following values unknown corresponding to the value 1 string corresponding to the value 0 symbolically c string integer corresponding to the value 1 symbolically int floating point corresponding to the value 2 symbolically 1oat The second field transfers the value retrieved from the tables Its type depends on the value of the first
41. standard Unix delivery or rex from Cocktail toolbox Aggregate of characters representing a lexical atom of a formal language well known examples of tokens are keywords indentifiers numbers separators Token comments etc The notion of token simplifies and clarifies the description of formal languages by means of context free grammars tokens are generated from the input character streams by scanner programs Internal data structure of an embedded server implementation installed on a diskless hardware platform which lets the server application imitate the file system of a Virtual File System device with the mass storage this structure is sometimes referred to as VFS or embedded file system WWW World Wide Web the aggregate collection of hypertext documents retrievable via Internet by means of the HTTP protocol Gloss 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424
42. struct lptrstack 10 lrepository InitRepository NULL ROOT page root lptrstack 0 BuildFileNode ROOT index_str 0 0 1 AppendNode lrepository lptrstack 0 lptrstack 0 BuildDirNode public lptrstack BuildFileNode gaugel Hello page str 0 1 1 nsertNode lptrstack 0 lptrstack lptrstack BuildFileNode gauge2 Hello page str 0 2 1 nsertNode lptrstack 0 lptrstack E lptrstack BuildFileNode di80 param form di80 param form str 0 3 1 nsertNode lptrstack 0 lptrstack lptrstack BuildFileNode dvc5000 1 dvc5000 str 0 4 1 nsertNode lptrstack 0 lptrstack lptrstack BuildFileNode dvc5000 2 dvc5000i str 0 5 1 nsertNode lptrstack 0 lptrstack AppendNode lrepository lptrstack 0 lptrstack 0 BuildDirNode images Page 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Configuration of Repository of Virtual file System lptrstack BuildFileNode alstom alstom img alstom img length 6 2 nsertNode lptrstack 0 lptrstack g lptrstack BuildFileNode Dr80Mimic DI80Mimic img DI80Mimic img length 7 2 nsertNode lptrstack 0 lptrstack Ne lptrstack BuildFileNode ccd ccd img ccd img length 8 2 nsertNode lptrstack 0 lptrstack 8 lptrstack BuildFileNode HartMimicl HartMimicl img HartMimicl img length 9 3 nsert
43. the directory the sub trees can be either leaves embedded files or embedded scripts or sub tree roots embedded directories of lower level access list tdata base struct pointer to a list of access records each storing a pair of character strings username password this feature provides the access control for the directory tdata base struct pchar reference of an adjacent node file or directory at the same level of the VFS pointer to the character string storing the name of the file file id unsigned short unique file serial number attributed to all VFS leaves nature unsigned short code describing the file formats can take on the values c text 1 c gif 2 c jpeg 3 java 5 script 6 c dir 4 corresponds to the directory file contents pchar pointer to a chain of bytes which stores the contents of a page an image or an applet size unsigned short length of the file expressed in number of bytes if this value is equal to 0 this means that the file contains a zero terminated character chain tdata base struct pchar reference of an adjacent node file or directory at the same level of the VFS pointer to the character string storing the name of the file file id unsigned short file serial number attributed to all VFS leaves nature unsigned short code describing the file formats can take the values c text 1 gif 2 c jpeg 3
44. this case less then 32768 characters After this operation the string is sent via socket and the transmission result is returned to the caller 2 3 5 5 Fault messages Failure of the routine s operation is reflected by the value returned by it In case of successful transmission the result should be positive and should correspond to the number of characters sent Negative or zero values correspond to transmission errors Page 3 34 Field Device Web Server Release 1 0 Software User Manual ALS 53424 2 3 6 Procedure int vsockbinsend int sock id char string unsigned short length 2 3 6 1 Description This routine is used to send a block of bytes of a given length to the network via a secondary socket The transfer mode corresponds to a non formatted write of a character stream to a file 2 3 6 2 Inputs The routine has three inputs sock int socket identifier string character string written to the socket length length of the string passed by the second parameter 2 3 6 3 Outputs The output provides the result of the transmission attempt It gives either a number of characters written to the socket or an error code resulting from the operation 2 3 6 4 Fault messages The operation failure is reflected by the value returned by it In the case of successful transmission the result should be positive and should correspond to the number of bytes sent Negative or zero values correspond to transmissi
45. this package for classification purposes ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 21 Use 2 1 Module Servengine The module servengine implements the driving mechanism of the server It provides two routines which both execute the algorithm of the iterative server communicating with the client via a TCP IP socket This algorithm is composed of a four stage execution loop preceded by an initialisation step for control flow see Figure 3 3 Figure 3 3 Flow diagram of the basic server loop The operation of the loop is driven by arrivals of request PDUs on the TCP IP socket PDUs are recovered from the socket and passed to a routine which analyses their contents The role of such a routine consists in verifying the structure of the PDU and in extracting the information necessary for further server loop operations This routine decides if the PDU is well formed or if there is an error in its structure In case of error detection the second processing stage reporting the error is activated In the case of correct reception the third stage is started This stage consists in generation of the server s response corresponding to the request correct or erroneous The single round of the loop is terminated by a clean up routine Page 3 22 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use The present software provides implementations for each processing stage of t
46. to the full specification described in 10 are as follows 1 Only POST and GET services are recognised 2 The object to be served is described by its access path NULL access path describes server by default object which should be on the server 3 The access path syntax is as follows ident_step_I ident_step_2 ident_step_n object_id ext 4 The type of requested object is identified uniquely by its extension The extensions recognised by this software are htm html HTML page cgi CGI script gif jpeg image class applet no extension directory 5 The only legal characters the path elements identifiers of directories are upper and lowercase letters figures underscore minus and plus 6 Identifiers in URL encoded form content can additionally contain periods 7 The identifiers should be shorter than 80 characters 1 CONTEXT FREE GRAMMAR OF HTTP REQUEST The text which follows represent the listing of the context free grammar describing the operation of the Parser module see chap 3 3 2 3 generated by the Lark processor 7 from the Cocktail toolbox ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 1 HTTP protocol specification for Field Device Web Server PARSER EXPORT ifdef __cplusplus include env class h endif GLOBAL include lt stdlib h gt define yyInitStackSize 20 define NO RECOVER define ERROR printf Syntax error in request n includ
47. to the list of objects contained in the title images plain text or formatted text objects align objects pchar thtml page elements title alignment description pointer to the list of objects contained in the form method pchar character string designating method used on the form submission action BuildPlainText text BuildApplet BuildHtmlTableCell Page 3 70 code pchar pchar character string designating the server object activated by the form submission pointer to the character string containing the text name of virtual file containing applet bytecode codebase pchar virtual directory containing applet code alt pchar character string which is displayed when image is pointed to by the applet width unsigned char width of the applet in pixels height align unsigned char pchar height of the applet in pixels alignment code for objects contained wthin the cell width unsigned char cell width in of table width colspan unsigned char nb of columns which span the cell rowspan unsigned char nb of rows which the cell spans objects Field Device Web Server Release 1 0 Software User Manual thtml_page_elements list of objects contained within the cell Table 3 14 Description of parameters according to function ALS 53424 Use ww BuildEmptyLines nr of lines
48. toolbox while the implementation is totally customised for the needs of this application var implements the routines constructing the elements of the so called Common Gateway Environment CGI the routines are mostly used by the Parser module basicencoder implements the decoding of basic cookies base 64 coded name password character chains in certain kinds of request PDUs The user is expected to use only two of them http_process fully and env_var marginally The modules Parser Scanner and Source are thought to be hidden by the http_process module Scanner and Source modules are in principle not expected to be used directly The advanced user may use the exposed interface of the Parser module ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 41 Among two remaining modules var is in principle considered as a collection of routines providing services to the Parser module Some of its interface is used by the modules from other packages The small module basicencoder is only used inside the package 3 1 Module process The module implements three basic operations linked to the analysis of incoming request PDUs initialisation of CGI environment active PDU parsing and finalisation of analysis The routines implementing these operations are directly accessible to users who are not required to understand the details of parsing operations
49. types have a very regular construction following this schematic typedef dll obj desc tKind unsigned char typedef dll obj desc tKind Kind dll obj desc tNodeHead yyHead object attribute fields yobject name The first field of each object is the tag Kind which identifies the object class The second field of the record is used by the internal modules to manage the pool of objects The rest of each structure is composed of the series of object attribute definitions In principle the user must not modify these attributes manually and should rely on the set of routines furnished by this module as well as by the modules gen tree module and html gen hl ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 57 Use The type of the first structure field is the sub type of unsigned char and takes on the values from to 35 The values of this type are redefined as a set of symbolic constants according to the following scheme Symbolic name attributed khtml_page Kind of object designated representation of an embedded HTML page kobject_list object class which represents collections of HTML objects contained in other structures knoobjects object marking the end of collection khtml_objects single element of object list khtml_page_object abstract class representing any element tag belonging to the HTML page like paragraph form table image etc kparagraph obj
50. via the network The two functions from this package are used to implement the reverse process i e the base 64 decoding algorithm 3 41 Function int getkey char 3 4 1 1 Description This function is used to compute the place of a character provided as its input in the base 64 coding vector 3 4 1 2 Inputs The only input is the character to be decoded 3 4 1 3 Outputs The output corresponds to the place occupied by the character in the coding vector 3 4 1 4 Fault messages If the character does not belong to the coding vector 1 is returned ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 53 3 4 2 Function unsigned short decode_four unsigned char inpbuf 4 char outstr unsigned char ptr 3 4 2 1 Description This routine produces three ASCII characters corresponding to a 24 bits entity represented by the four elements of the vector passed via the first routine s parameter The ASCII characters are placed in the character string whose reference is passed via the second parameter The characters are written into the string starting from the position indicated by the third routine s parameter The result returned corresponds to the next free place within the string i e its value is equal to the value of the third parameter increased by three 3 4 2 2 Inputs The three input parameters are as follows four element array of integers containing 4 consecutive nibbles of 6 bi
51. width width of the line in unsigned char height height of the line in points pchar align reference of a string representing line s alignment mode insert plain text thtml page elements page pchar text pchar text reference of the text to be inserted insert formatted text thtml page elements page pchar text pchar colour unsigned char size unsigned char unsigned char unsigned char pchar text reference of the contained text of the formatted text object pchar colour denomination of the font colour unsigned char size font size unsigned char is Bold when set this flag formats the text to bold unsigned char is Blinking when set this parameter makes the text blink unsigned char style paragraph style predefined from H1 to H5 insert link thtml page elements page thtml page elements element list pchar ref pchar target unsigned char isref thtml page elements list of elements contained in the link object element list pchar ref URL of objects referenced by the link pchar target target for displaying the object referenced by ref attribute unsigned char isref when set flag signifies that the object is a hyperlink and when reset means that the object is an anchor insert simple link thtml page elements page pchar text pchar ref pchar target unsigned char isref pchar reference of text to be inserted into link pchar ref URL of objects referenced by the link
52. 1 5 make html form pchar action pchar method unsigned char nr of obj action pchar URL of an object which will be activated after the form submission method pchar method used for the submission POST or GET create table cell pchar align unsigned char char nr of obj width unsigned char collspan unsigned char rowspan uchar align pchar alignment style of the cell width unsigned char cell width in 96 collspan unsigned char cell column span in pixels rowspan unsigned char cell row span value in pixels create table row unsigned char nr of objects No parameters in the first group since row object does not have any particular attribute append rows to table thtml page elements table unsigned char nr of objects table thtml page element s table pointer to a table to which rows will be appended Table 3 11 Description of first group parameters 4 2 1 3 Outputs Each function generates an object referenced by the pointer of the thtm1 page elements type The kind of object corresponds to the routine s role and is described in the previous table 4 2 1 4 Fault messages No fault message is generated If a routine fails to create an appropriate object the NULL pointer is returned 4 2 2 Routines which append simple objects to html pages 4 2 2 1 Description The role of these routines consists in appending an html object to a p
53. 1 3 2 1 Description This routine creates in the system heap a new node of the type embedded directory 1 3 2 2 Inputs The only input of the routines is a pointer to a character string which contains the directory s name 1 3 2 3 Outputs The routine returns the pointer to the newly created embedded directory object 1 3 2 4 Fault messages If the node creation fails the routine returns NULL 1 3 3 Function data base struct BuildFileNode pchar name pchar contents unsigned short size unsigned short fid unsigned short nature 1 3 3 1 Description This routine creates in the system heap a new node of the type embedded file 1 3 3 2 Inputs The routine has the following inputs name pointer to a character string which identifies the file within the VFS tree contents pointer to a contiguous memory area byte string containing the file contents size number of bytes contained in the area if this parameter is equal to 0 the file contents is considered to be a zero terminated character string fid numeric file identifier support for fast file referencing nature code of file contents it can take on the following values c unknown 0 c text 1 c gif 2 jpeg 3 c script 6 java 5 and c dir 4 1 3 3 3 Outputs The routine returns the pointer to the newly created embedded file 1 3 3 4 Fault messages When the node creation fails the routine return a NU
54. 2215 Description x4 inesse RD aa eb LED Chae EY IRE SE 3 10 ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 9 Contents Page 10 1 3 3 1 3 4 1 3 5 1 3 6 1 3 7 1 3 8 1 3 9 1 3 10 1 3 11 1 3 12 1 3 13 173222 Inputs he 3 10 1 3 2 3 OUtputs ee pure 66 3 10 1 3 2 4 Fault Messages Rec e pe RR ERE Regex AES Ehe 3 10 Function tdata base struct BuildFileNode pchar name pchar contents unsigned short size unsigned short fid unsigned short nature 3 10 1 3 3 T D seripiioh We 3 10 1 35 32 en aede de es ra Cte eade ad 3 10 1 3 3 3 OUtpUutS 3 10 1 3 3 4 Fault messages oe ur ee Renee t iiw og nee pa 3 10 Function tdata base struct BuildScriptNode pchar name tscript exec unsigned short fid 3 11 1 3 4 1 Description s verom event ELVIS RU POCO ean eer ae a 3 11 13 42 Inputs ea coi ter eere ee arc Re TA 3 11 13 53 Outputs ee eg EE 3 11 13 44 Fault messages c E eR ep e reete ae S e I EXE 3 11 Procedure void InsertNode tdata base struct dir tdata base struct node 3 11 1 3 5 T DeScription EEE TET TO eed tates F Wes cbe nu E 3 11 1 3 5 2 Inputs Le tas deed mas A 3 11 1 3 5 3 O tputs
55. 6 Servengine package this package groups the modules which provide the functions of server engine operation network adaptation and persistence of request data HTTP Analysis package this package implements the functions of request analysis and CGI environment building DBgen package this package provides the elements which support the implementation of the embedded equivalent of a disk file system HTML gen package this package provides the elements which support the implementation of embedded HTML pages Sendback package implements basic response composition functions HTMLGen Analysis Servengine Sendback Figure 1 4 General architecture of Field Device Web Server software Field Device Web Server Release 1 0 Software User Manual ALS 53424 Chapter General information 2 1 UTILISATION CONTEXT The software described in this manual is in principle independent of the implementation platform i e the processor type operating system and network stack A few implementation details can be adapted to almost any environment provided that the environment supports ANSI C run time routines Clearly you need to use the development tools compiler linker loader to install the generated code in its environment The unique requirement imposed on the hardware platform consists in the availability of free space
56. 6 4 2 1 4 Fault messages Leeds er ane rare sei reg od Ce ve e ts 3 66 4 2 2 Routines which append simple objects to html pages 3 66 422 1 Description Lu vA AB REN UR PC PE DU TI EN ne reed 3 66 4 2 22 Inputs EESTI 6 3 67 4 2 2 3 Outputs Re erect eg mE EI Sy 3 68 4 2 2 4 Bault messages Deep ERI Pe p Errem 3 68 4 3 Module gen tree module 3 69 4 3 1 Routines which generate HTML related objects 3 69 43 1 1 DesCrnp oti Lc od aus each ase EE OD 3 69 48252 Inputs Mice pep ERST IE USER Ee t OES er ER HR 3 70 4 3 1 3 Outp ts i oe ee Omne ER Soles EE 3 71 314 Fault messages o cote ERE a d Rd 3 71 4 3 2 Routines which modify the structure of HTML related objects 3 72 4 32 1 Description oso cse UD dane nek See Lowel Mee eee dee 3 72 4 3 2 27 LIBDULS 3 72 4 3 2 3 OUtputs a 3 72 4 3 2 4 Fault Messages ende epa 3 72 4 4 Module html conv module 3 73 4 4 1 Function unsigned short HtmlPageToString pchar buffer unsigned char buff ptr thtml page elements html
57. 6 2383 OUMU sg ss Sneha ss Sak wpe Nga NIE e IRR Boe 3 36 2 3 8 4 Fault messages eau mere 3 36 Field Device Web Server Release 1 0 Software User Manual ALS 53424 a en Contents 2 4 Module data base module 3 37 2 4 1 Procedure void init data base void 3 37 ZA le Description s n o eS A RERSUCapegq REIS BOR 3 37 2 4 12 Inputs bales vale Ons pere hey E 3 37 2 4 1 3 OUMU qoe e GLO SR tee eS RATS 3 37 2 4 1 4 Fault messages ene 3 37 2 4 2 Procedure void get db data char name tdb result result 3 38 2 421 Des riptiOD s cease eo 3 38 24422 Inputs cheer Se ue Re PY ve am RS 3 38 2 4 23 OUPA ee EXERCERE eed Rez NECS NS E EA 3 38 2 4 2 4 Operational processing 2 3 38 2 425 Fault messagES esce eee Re Hs WR arose ORG 3 39 2 4 3 Procedure set_db_data char name unsigned char val type void value 3 39 24 92 Description 4 4 0 GaP 3 39 25453 25 EE AAEE WP 3 39 288 S 3 39 2 4 3 4 Operational processing 3 39 245229 eR 3 40 2 4 4 Procedure char get first
58. Automation cells of a control system co operate in order to implement a coherent control application The co operation is possible thanks to information exchanges via a higher level network which forms the system backbone This backbone links the automation cells with the control room supervisory computers which implement the interface between the system and human operators In most cases control applications are arranged in two sets of functions automation functions implemented in automation cells and supervisory functions implemented in control room computers Information exchange between the two parts is based almost exclusively on the client server paradigm Data streams exchanged between control room client software and automation cell servers transit via the backbone network of the system which in most cases is based on the Ethernet link layer and supports information transport via the TCP UDP IP protocol stack Application data exchange is implemented by the variety of higher level protocols mostly proprietary and sometimes standardised MMS FTP Application protocols influence the structure of client and server software which varies greatly from one system to another Non standard protocols result in non standard solutions in terms of services provided flexibility performance and complexity This lack of compatibility strongly reduces the migration of software components from one application to another and virtually excludes the portability of
59. Field Device Web Server Release 1 0 Software User Manual ALS 53424 First issue 02 2000 Meaning of terms that may be used in this document Notice to readers WARNING Warning notices are used to emphasize that hazardous voltages currents temperatures or other conditions that could cause personal injury exist or may be associated with use of a particular equipment In situations where inattention could cause either personal injury or damage to equipment a Warning notice is used Caution notices are used where there is a risk of damage to equipment for example Notes merely call attention to information that is especially significant to understanding and operating the equipment This document is based on information available at the time of its publication While efforts have been made to be accurate the information contained herein does not purport to cover all details or variations in hardware or software nor to provide for every possible contingency in connection with installation operation or maintenance Features may be described herein which are not present in all systems ALSTOM assumes no obligation of notice to holders of this document with respect to changes subsequently made ALSTOM makes no representation or warranty expressed implied or statutory with respect to and assumes no responsibility for the accuracy completeness sufficiency or usefulness of the information contained herein ALSTOM gives no
60. LL pointer Page 3 10 Field Device Web Server Release 1 0 Software User Manual ALS 53424 1 3 4 Function data base struct BuildScriptNode pchar name tscript exec unsigned short fid 1 3 4 1 Description This routine creates in the system heap a new node of the type embedded script 1 3 4 2 Inputs 9 name pointer to a character string which identifies the file within the VFS tree exec pointer to a routine which is executed when the node is referenced in a http request this pointer has the type t script exported by the data base struct module the type definition is typedef void tscript int fid numeric file identifier support of the fast means of file referencing 1 3 4 3 Outputs The routine returns the pointer to the newly created embedded script 1 3 4 4 Fault messages When the node creation fails the routine return a NULL pointer 1 3 5 Procedure void InsertNode tdata base struct dir tdata base struct node 1 3 5 1 Description This routine adds the VFS node referenced by its second parameter to the directory referenced by its first parameter 1 3 5 2 Inputs The two procedure inputs are dir pointer to an existing directory node if this pointer is equal to NULL no operation is performed node pointer referencing an existing VFS node which can be of an embedded file an embedded script or an embedded directory kind if the pointer does not point to a node of
61. Node lptrstack 0 lptrstack ey lptrstack BuildFileNode sensor sensor img sensor img length 10 2 nsertNode lptrstack 0 lptrstack lptrstack BuildFileNode valve valve img valve img length 11 2 nsertNode lptrstack 0 lptrstack DET AppendNode lrepository lptrstack 0 lptrstack 0 BuildDirNode javadir lptrstack BuildFileNode Trend Trend bcode Trend bcode length 12 4 nsertNode lptrstack 0 lptrstack ey AppendNode lrepository lptrstack 0 return lrepository Figure B 2 Example of skeleton constructing routine This procedure builds the skeleton tree which spans the VFS repository presented as follows Repository root Directory public Directory images Page by default Directory javadir Figure Virtual File Tree The repository skeleton generated by the procedure contains e one by default page named ROOT e directory public which contains five HTML pages gaugel gauge2 4180 param form dvc5000 1 and dvc5000 2 e directory images which contains six images in gif and jpeg format a1stom DI80Mimic ccd HartMimicl sensor and valve e director javadir which contains one file Trend ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 Configuration of Repository of Virtual file System Page B 4 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Appendix Embedding HTML Pages Images C Applets
62. PDU analysis The Parser specification is done in an appropriate language which describes structure of PDUs in terms of context free grammar The equivalent compilable files in C language are produced automatically by Lark The exported interface is simple but its comprehension requires deeper insight into the theory of compilation This interface is exhaustively described in 7 The user of Field Device Web server software is freed from the burden of calling the Parser interface functions by the wrapper routine ParseFromSocket 3 3 Request parameters needed to interpret correctly service requests addressed to the server are embedded within the structure of incoming PDUs In order to structure the processing of these requests the server operation is split into the phases of parameter extraction and request execution The parameter extraction phase is done during the parsing process The parser routine calls the functions from the interface of this module in order to store the values of request parameters in the appropriate data structures often called CGI parameters Processing routines recover data structures from the created request context and execute programmed operations The environment data structures Module env_var are defined in the following table Exported variable method Type or type of table elements unsigned char Description access method POST or GET possible values httpGET 1 and httpPOST 2 major versio
63. Sockintert seb 3 31 2 3 1 Procedure int initsockets void 3 31 2 3 I T Description vnd eR REA REIR he genes 3 31 2 3 1 27 metres tern 3 31 2 3 1 35 Outputs 2 5 ds eeu 3 31 2 3 L4 Fault Messages xe e a eer E ER E aba HAE Ee eg 3 31 2 3 2 Procedure int passivesocket unsigned short port type int quelen 3 32 23 2 T 2D scription is uve ehe We ES MON ue NEP eed alee hr eden 3 32 2 3 22 APU Lecce cobre RE NE es BES a eee meg AE Eg 3 32 2 32 93 i soient eh bmp BUR Rn Gena domed een oS e wet ere 3 32 2 3 2 4 Operational processing 3 32 2 3 2 3 FPaultimessagesu dx bare e Ee 3 33 2 3 8 Procedure int waitforconnect int main sock 3 33 2 3 3 1 Description pits Hehe OS 3 33 2353 22 Inip ter RS ooa SEAT op Se i Ree SR gts 3 33 2 3 3 3 gt n een ys DO ei es Se 3 33 2 3 3 4 Operational processing 2 3 33 255929 HAUG IMESSARES ep E ie Ra o uerus eoe UR 3 33 2 3 4 Procedure int closestream int sock id 3 34 2 3 4 1 Descriptions or eg See Sh Soares e S 3 34 ABAD oh osse mE
64. Software User Manual Page B 1 Configuration of Repository of Virtual file System define yyFREE p s Free s char p define closepchar a if close char a tg ROPERTY INPUT RULE repository name pchar PE CS BATES TS root member_list node access_list default_obj_name pchar COOL r node next node lt embedded_directory member_list node access list embedded active node file_id ushort nature ushort lt embedded_file content pchar size ushort embedded_script Sa RESOURCE PATH ABSTRACT SYNTAX path step pchar next path ACCESS LIST ABSTRACT SYNTAX access_list user pchar password pchar next access_list END AbstractSyntax Figure B 1 Structure of the repository skeleton script exec tscript The ast processor 9 transforms this grammar into an abstract data type which is implemented in the module data base structure see chap 3 1 2 The routines used to generate and process this data structure are placed in the module data base processing see chap 3 1 3 and generated with the Puma processor of the Cocktail toolbox 8 The routines from these two modules are used to build the VFS repository skeleton An example of a skeleton constructing routine is presented in Figure B 1 tdata base struct db page repository void tuata base struct lrepository tdata base
65. Web Server Release 1 0 Software User Manual Page 3 49 3 3 5 Procedure void print_env void 3 3 5 1 Description This routine is used only for debugging purposes It prints on the standard output server console the values of all environment variables in a comprehensive format 3 3 5 2 Inputs None 3 3 5 3 Outputs None 3 3 5 4 Fault messages None 3 3 6 Procedure void extract_auth void 3 3 6 1 Description This routine is used to extract the values of two environment variables username and userpass from the string retrieved as the value of the authentification option in the environment table The prerequisite for correct operation of this procedure is that this option be present in the request PDU and that the authentification coding is of the basic type base 64 encoding If these two conditions are not fulfilled the routine fails and the result of its operation is unpredictable In the case of successful operation the routine retrieves the encoded user name and user password strings and copies them to the previously allocated heap frames as null terminated strings Heap frame allocation is performed using the AllocTokenStr routine 3 3 6 2 Inputs None 3 3 6 3 Outputs None 3 3 6 4 Fault messages None Page 3 50 Field Device Web Server Release 1 0 Software User Manual ALS 53424 3 3 7 Procedure void add_cgi_par unsigned char par_type value 3 3 7 1 Description This pro
66. age object The module provides six routines whose role is described in the following table Routine insert empty lines Appends a series of empty lines to the page Role insert horizontal line Appends a horizontal line to the page insert plain text Appends a plain text paragraph to the page insert formatted text Appends a formatted text object to the page insert link Appends an html link to the page insert simple link Appends a simplified link with plain text only to the page Table 3 12 Routine role Page 3 66 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 4 2 2 2 Inputs The signatures of the routines follow a regular scheme thtml_page_elements lt routine name gt thtml_page_elements page lt attribute section gt The first input parameter of the procedure is always the reference of an HTML page object on which the routine will operate This parameter is followed by the object attribute section whose contents varies from one routine to the other The following table describes the attribute section for each routine of the group Routine Parameter Meaning insert_empty_lines thtml_page_elements page unsigned char nr_of_lines unsigned char nr_of_lines number of empty lines to insert insert horizontal line thtml_page_elements page unsigned char width unsigned char height pchar align unsigned char
67. and environment construction routines The routines exported by this module are used within the routines of the servengine package by default for the parsing and finalisation phases of the main server loop see the two routines of 2 1 3 1 1 Procedure void InitParser void 3 1 1 1 Description This routine initialises the analysing process environment it activates an isolated operation which prevents the scanning routine to crash in case of fatal errors Although the fatal errors of parsers are extremely improbable calling this routine is recommended at the beginning of the analysis phase of the server s loop see 2 1 The fatal errors will cause the server to print on error stream a message Scanner Exception caught 3 1 1 2 Inputs None 3 1 1 3 Outputs None 3 1 1 4 Fault messages None 3 1 2 Procedure unsigned short EndParsing int socket id 3 1 2 1 Description This routine finalises the process of PDU analysis It is proposed as the standard choice for the finalisation phase of the basic server loop see 2 1 3 1 2 2 Inputs The secondary socket is to be closed by the routine 3 1 2 3 Outputs The result of a close operation If this result is positive the closing operation is successful Page 3 42 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 3 1 2 4 Fault messages None 3 1 3 Procedure unsigned short ParseFromSocket int socket id 3 1 3 1 Descri
68. ary nodes of the embedded_directory kind located on the path between the tree root and the searched node The routine verifies the access rights at every stage of the search process i e while visiting the intermediary directories The credentials valid for the search process are provided by the third and fourth parameters of the routine 1 3 7 2 Inputs The four routine inputs are root pointer to an existing root node of a VFS tree repository if this pointer is equal to NULL no search is initialised path reference of an object which represents the path to be followed during the search process the path is composed of a series of steps which reference by name the directory nodes lying between the tree root and searched object user pointer to the string which contains the user name this parameter represent the credentials to be verified at every level of the searched tree password pointer to the string which contains the user password this parameter completes the user name in credential verification 1 3 7 3 Outputs The routine always returns a reference to an object of tdata base struct type or a NULL pointer If the search process succeeds the object referenced by the pointer is either the tree root an embedded file an embedded directory or an embedded script 1 3 7 4 Fault messages The routine fails when it does not return a reference to an existing tree node No explicit textual message is
69. ase of many non recognised options in a request PDU the element 31 stores the last option Elements 0 20 30 are not used and reserved for further extensions The module exports two types in order to support the retrieval of values of cgi parameters present in the header line of the request PDU union adapted to store the values of one of the recognised types of cgi parameters integer float or string defined as follows typedef union pchar string int integer float real url val ALS 53424 a en Field Device Web Server Release 1 0 Software User Manual Page 3 47 structure storing values and types of cgi parameters defined as follows typedef struct cgi_par_tag unsigned char par_type url val value tcgi par Symbolic values corresponding to the recognised types of parameters are as follows c string 0 c int 1 c real 2 On these data structures some routines of this module are run and described in the following sections 3 3 1 Function char AllocTokenStr unsigned long length 3 3 1 1 Description This routine is provided in order to create on the system heap a null ended string The string thus created can contain up to length characters The string content is not initialised by this routine 3 3 1 2 Inputs Number of characters in the string without terminating null character 3 3 1 3 Outputs Pointer to the reserved heap space 3 3 1 4 Fault messages If the allocation
70. ation interface to different transport protocols sockets are mostly used on top of the TCP IP stacks Compiler Compiler Toolbox Karlsruhe a collection of co operating highly efficient software tools used to generate compiler modules Image coded in one of the well known compact formats GIF JPEG and stored within the embedded file system of host equipment Servers designed to be placed in small devices their characteristics are small code size no disk storage and no sophisticated software interfaces such as interface to data base or interface to script languages HyperText Markup Language a variant of SGML a meta language used to describe the layout of printable documents Hypertext Transfer Protocol one of Internet s most used application protocols It is based on TCP IP and is used to transport hypertext documents Interconnected Networks a world wide communication infrastructure composed of many thousands of interconnected Local Area Networks The networks share the same communication technology based on the pair of protocols TCP and IP Transmission Control Protocol and Internet Protocol INTERNET technology has its origins in a DOD supported project ARPA The results of this project were made public in the 1980s and were followed by the ever growing arrival on the market of open network applications Field Device Web Server Release 1 0 Software User Manual Gloss 1 Glossary Internet browser Internet client age
71. bstract class 3 59 Table 3 9 Description of non abstract class attributes continued 3 60 Table 3 9 Description of non abstract class attributes continued 3 61 Table 3 10 Routine description 3 65 Table 3 11 Description of first group parameters 3 66 T ble 3 12 Routine role canta Ese bee REP RR eel ness E 3 66 Table 3 13 Description of the attribute section for the six first group routines 3 67 Table 3 14 Description of parameters according to function 3 70 Table 3 14 Description of parameters according to function continued 3 71 Table 3 15 Description of routines 1 3 72 18 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Chapter Presentation 1 This manual describes the collection of software packages called in the sequel Field Device Web Server The rationale for this product is to support the technology which enhances control system architectures and especially fieldbus based parts of these architectures with the potential for INTERNET compatible processing The use of this t
72. cedure is called in principle by the PDU parser It pushes a new cgi parameter on the cgi_params stack if the stack is neither overflowing nor underflowing The structures storing parameter types and parameter values are created on the system heap If the parameter is of the c_string type the corresponding string is first decoded by the call to the decode url str routine and then stored in a frame allocated in the system heap 3 3 7 2 Inputs The routine has two inputs parameter type and parameter value 3 3 7 3 Outputs None 3 3 7 4 Fault messages and failure modes No explicit message is generated In the case of stack overflow or underflow the routine returns without any effective operation If the creation of the heap frame for the structure fails the routine returns with a NULL element pushed on the stack In the case of the c string type of parameter value when the allocation of the heap frame fails the value of the corresponding parameter pushed on the stack is unknown 3 3 8 Function char decode url str char inpstr 3 3 8 1 Description This routine implements the decoding of URL encoded strings recovered as values of cgi parameters of type strings or as values of data of string types appended to POST service request PDUs The routine when successful returns a decoded string corresponding to the input string containing URL coded symbols The decoding method implemented here is as follows every symbol i
73. choose the port on which the server will operate All server phases are implemented by the predefined routines listed in Table 3 3 Page 3 24 Field Device Web Server Release 1 0 Software User Manual ALS 53424 2 1 2 2 Inputs The single input parameter of the routine provides the port number on which the server will operate 2 1 2 3 Outputs The routine does not provide any output values 2 1 2 4 Operational processing This routine calls the routine server loop with the first parameter set to its input parameter and four others set to NULL This mode of calling server loop will force the operation of the server with the predefined implementation of the processing phases and frees the user from the burden of programming The procedure is a recommended entry point for software users who wish to concentrate their efforts on application development 2 1 2 5 Fault messages None ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 25 Use 2 2 Module Sendback The module sendback contains the routines provided for the standard implementation of the response composition phase of server operation It exports two variables script routine send page routine four routines response composer generic sendback routine generic error report typed server prompt The module also exports one type of definition typedef int tprocessor int The type
74. close_char Figure 3 1 Module relationship within the package VFS Generation This module groups the data type definitions necessary for other modules from the package in which it is implemented but also for other packages It provides directly one data type pchar which is the pointer to a heap allocated character string This type has two operations directly associated with it init char which is the string creator and initialiser and close char which is the string destructor Two other types uchar and ushort are defined by renaming other type descriptions are imported from standard definitions via appropriate Zinclude lt gt clauses As far as this operation is concerned the module plays the role of the adapter to different compiler environments Page 3 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424 1 1 1 Function char init_char const char 1 1 1 1 Description This routine implements the creation of a character string If the input parameter references an existing string of non zero length the routine attempts to allocate on the system heap a memory zone which has the length of the input string length 1 If the allocation succeeds the input string is copied into the zone If the input parameter is NULL or if the referenced string has zero length or if the allocation fails the routine returns NULL 1 1 1 2 Inputs The unique input parameter is a pointer referencing an existin
75. cter string according to the following procedure 1 the original string is divided into a sequence of groups of three characters 2 the group of three characters is considered to be an entity composed of 24 bits The last group can have one two or three characters If the last group is incomplete the corresponding entity is filled with 0 on its least significant bits 3 Each entity is decomposed on 4 nibbles each having 6 bits The nibbles are interpreted as integers the values of these integers lie within the interval 0 63 At that stage the string on n characters is replaced by the sequence of k integers where k n div 3 m 4 if n mod 3 2 0 m 0 else m 1 4 The sequence of k integers is replaced by the sequence of k characters selected in the coding vector V composed of 64 ASCII characters In the base 64 standard the coding vector is composed as follows e first 26 places 0 25 are occupied by the uppercase letters A Z e next 26 places 26 51 are occupied by the lowercase letters a z e next 10 places 52 62 are occupied by digits 0 9 last two places 62 63 are occupied by characters 5 Each integer is replaced by the character V x trailing zero integers are replaced by character 6 The algorithm produces the sequence of k ASCII characters The most widely implemented authentification procedure uses this coding algorithm to encrypt the user name and user password sent
76. ction backhome onclick location 2 s form method POST action public di80 param form htm lt div align center gt lt center gt lt p gt lt strong gt lt font face FuturaA Md sizez 5 PASSWORD ERROR lt font gt lt strong gt lt p gt lt center gt lt div gt lt align center gt s amp nbsp amp nbsp amp nbsp lt p gt lt align center input type submit value BACK s name SendButton amp nbsp lt INPUT id backhome language javascript name backhome onclick return backhome_onclick type button value Home style font family FuturaA Md BT font weight bold p EON body html Figure D 2 Skeleton of the page from the example Page D 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424 The section of program which makes this page resemble Figure D 1 is as follows rong 0 10 0 tatus age_template trlock strerrmess strbuttext 10 01 char strerrmess 40 char strbuttext 10 trcpy strerrmess Your password is re enter it trcpy strbuttext TO FORM SO GI IIT CES sock id Figure D 3 Part of Figure D 1 program Serving dynamic HTML This section of the program makes use of the routine sockprintf from the module sockinterf see chap 3 2 3 5 It is also assumed that the variable page template takes on the value of the character string representing
77. ded directory if this pointer is equal to NULL no operation is performed proc reference of a routine which allows the user to program the operation to be performed on the node the data type of this parameter is defined as follows typedef int tnameproc pchar int int No processing is done if this parameter is NULL 1 3 10 3 Outputs None 1 3 10 4 Fault messages None 1 3 11 Function pchar InstallFileContent tdata base struct root tdata base struct path pchar contents unsigned short length 1 3 11 1 Description This function links a memory area to a VFS tree file the file location in the tree is referenced by the path object passed by one of the parameters of the routine 1 3 11 2 Inputs The routine has four parameters root pointer to a root of an existing VFS if this pointer is equal to NULL the operation has no effect and the function returns NULL path path object which localises the node within the VFS tree if this pointer is equal to NULL the operation has no effect and the function returns NULL contents pointer to a contiguous memory area storing the bytes which form the body of the embedded object page image Java byte code length parameter which stores the length of the region pointed by contents this parameter is zero for null terminated character strings 1 3 11 3 Outputs The routine returns the pointer to the region if the installation process was d
78. des the front end routine converting the internal structure of embedded pages to a character oriented representation The relationships between the modules of the package are showed by the diagram in Figure 3 6 Page 3 56 Field Device Web Server Release 1 0 Software User Manual ALS 53424 41 Module html page elements This module defines data types and routines on which is constructed the internal representation of embedded HTML pages The most important item defined by the module is the data type thtm1 page elements Although the module is coded in ANSI C programming language only a small part is directly written in C The vast majority of code including the data type definition is automatically generated by ast one of the processors belonging to the Cocktail toolbox see chap 2 2 The original specification of the module is done using the ast syntax 9 Apart from the data type the module provides the definition of the three following functions 4 1 1 Definition of thtml page elements data type The definition of thtm1 page elements follows the regular scheme typedef union yobj type name 1 obj type name 1 yobj type name 2 obj type name 2 yobj type name n obj type name n thtml page elements The type is a pointer to a union which groups the structures Each variant of the union designates the type of object belonging to the HTML objects belonging to the embedded server pages These
79. e commondef h ifdef _ cplusplus define EnvObjectPrefix http_env else include env var h define EnvObjectPrefix endif include data base module h unsigned short recover res category const char res ext if stremp res ext htm 0 strcmp res ext html 0 strcmp res ext HTM 0 strcmp res ext HTML 0 else if strcemp res ext gif 0 strcmp res ext GIF 0 else if strcemp res_ext jpeg 0 strcmp ext JPEG 0 return c_jpeg else if strcemp res_ext class 0 strcmp res ext CLASS 0 net nae cg Vi else if strcmp res ext cgi 0 strcmp res ext CGI 0 Page A 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424 a en protocol specification for Field Device Web Server ALS 53424 Field Device Web Server Release 1 0 Software User Manual protocol specification for Field Device Web Server Field Device Web Server Release 1 0 Software User Manual ALS 53424 protocol specification for Field Device Web Server ALS 53424 Field Device Web Server Release 1 0 Software User Manual protocol specification for Field Device Web Server Field Device Web Server Release 1 0 Software User Manual ALS 53424 protocol specification for Field Device Web Server ALS 53424 Field Device Web Serv
80. echnology allows control systems to take advantage of the INTERNET type client server architecture where elements of the user interface to applications placed in field devices including their look and feel part are provided by the server Itis worth stressing that one of the most important features of the technology developed and supported by the software described below is that it should provide components which enhance rather than replace existing applications hosted by a control device The principal mission of a device in which the embedded INTERNET components are to be installed is by no means changed Control room console Interconnecting network Process computer Field devices Fieldbus Automation cell Figure 1 1 Place of field devices in automation system ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 1 1 Titre de chapitre variable To sketch the impact of the technology it is important to identify the place of a field device in a typical architecture of a control system as shown in Figure 1 1 The field device is part of an automation cell a collection of co operating instruments which provide a well defined automation function These devices are of different levels of complexity from simple sensors with extremely limited functions to process computers equipped with powerful processors and large memory banks containing large quantities of embedded software
81. ect representing paragraph tag kscript object representing script tag kbasic_object abstract class which represents any tag except paragraph and script kinsertable_object abstract class representing objects which can be inserted into other objects of basic_object type kformatted_text objects representing pieces of HTML text having such features as colour alignment style font size etc khtml_image object representing image embedding tags kplaintext objects representing plain non formatted text kseparator abstract class grouping empty lines and horizontal lines kemptyline object representing a group of empty line lt BR gt tags kline object representing horizontal lines khyperlink object representing hyperlink tag khtml table object representing HTML table khtml form object representing HTML form kapplet object representing applet embedding tag ktable cell object representing a single cell of an HTML table ktable row object representing a single row of an HTML table ktable title object representing title of an HTML table kinput desc abstract class representing tags which are used to build HTML forms kinput any form element except for an image kbutton button form field ksimple input abstract class representing three types of form element classes hidden reset and submit khidden ksubmit
82. ed by the object is returned to the system 4 1 3 2 Inputs The input parameter references the object to be destroyed 4 1 3 3 Outputs None 4 1 3 4 Fault messages None Page 3 62 Field Device Web Server Release 1 0 Software User Manual ALS 53424 4 1 4 Function himl_page_elements_IsType thtml_page_elements object uchar Kind 4 1 4 1 Description This routine checks whether the object referenced by its first parameter is of the type referenced by the second parameter The object is considered to be of the given type in two cases it belongs to a sub type of the specified type ex plaintext is of type kbasic object and kinsertable object itis strictly of the specified type applet or is of type kapplet 4 1 4 2 Inputs The first input parameter references the object the second provides the type to be checked with 4 1 4 3 Outputs The function returns 1 if the object is of the specified type and 0 if it is not 4 1 4 4 Fault messages None ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 63 Use 4 2 Module Aitml gen hl This module groups routines of two types The first group is composed of eight routines which create container objects of the thtm1 page elements type Container objects are objects which possess a collection of other objects Tables scripts links and formatted texts are container objects since they can contain simple objects like
83. ed servers using this technology as support for their projects 2 CONTENT OF THIS MANUAL Chapter 1 Presentation this chapter presents the background of the FieldWebServer as well as its architecture Chapter 2 General information this chapter introduces basic information about the utilization context and the specific package Cocktail It also deals with the start stop procedures Chapter 3 Use this chapter presents for the four packages the functions and procedures of each module 3 RELATED PUBLICATIONS INTERNET COMMUNICATIONS STEP 1 Software Development Plan Y3 30 4418982 A 1 INTERNET COMMUNICATIONS STEP 1 Internet Techniques in Distributed Control Systems Tutorial Y3 30 A419463 1 2 INTERNET COMMUNICATIONS STEP 1 System Specifications and Design Document Y3 30 419481 3 SOCKAPI SOCKETS Software Specification Document Y3 30 A419465 B 4 J Grosch Generators for High Speed Front Ends Report N 11 CoCoLab Datenverarbeitung 5 J Grosch Rex A Scanner Generator Report N 5 CoCoLab Datenverarbeitung 6 J Grosch Lark An LR 1 Parser Generator with Backtracking Report N 32 CoCoLab Datenverarbeitung 7 J Grosch Puma A Generator for the Transformation of Attributed Trees Report N 26 CoCoLab Datenverarbeitung 8 J Grosch Ast A Generator for Abstract Syntax Trees Report N 15 CoCoLab Datenverarbeitung 9
84. edefined values which are kradio or kcheckbox unsigned char character string which contains identifier of group to which object belongs pchar character string which contains the name of the object unsigned char flag which indicates if the object is displayed as checked character string which contains the input identifier unsigned char control s height in rows unsigned char control s width in columns text to be displayed initially in the control Table 3 14 Description of parameters according to function continued 4 3 1 3 Outputs All the routines return a pointer of the thtm1 page elements type which references the created object of a given kind In case of failure of the routine a NULL pointer is returned 4 3 1 4 Fault messages There is no explicit fault message The only reason for a routine to fail is lack of room in the system heap In this case a NULL pointer is returned ALS 53424 a en Field Device Web Server Release 1 0 Software User Manual Page 3 71 Use 4 3 2 Routines which modify the structure of HTML related objects This set of routines is designed to complete the generation of objects such as pages forms table rows and tables All these objects can contain other objects normally attached to them as a chain of objects The following routines help to create and handle the chains 4 3 2 1 Description This group of
85. eld Device Web Server Release 1 0 Software User Manual ALS 53424 Chapter Use 3 1 PACKAGE VFS GENERATION The package regroups the modules which provide the services linked to the generation and handling of the Virtual File System The package is composed of three modules module commondef widely used all over the software it defines the primitive data type pchar widely used the whole Field Device Web Server software module data_base_struct defining the fundamental data type tdata_base_struct on which the construction of the VFS is based module data base processing providing the routines which are used in the processing of the elements of VFS The relationships between the modules of the package are shown in the diagram in Figure 3 1 ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 1 Use data_base_structure Makedata_base_struct Releasedata_base_struct data_base_struct_IsType data_base_processing InitRepository BuildDirNode BuildFileNode BuildScriptNode InsertNode AppendNode FindNode GetNodeRef ProcessNode AppendStep PathToString StringToPath PrintPath PrintNode PrintRepository 1 1 Module Commondef SearchNodeInWidth InstallFileContent InstallAuthorisation RecoverResName commondef 22 init char
86. eld Device Web Server Release 1 0 Software User Manual Page 13 Contents 23225 IN puts ese 3 48 3 3 2 3 oerte eter vr Heer EM Rn pr E een eC 3 48 2 3 2 4 Fault Messages co ck See eons PAG Ce ROPA wae ee PER 3 48 3 3 83 Procedure void clean env void 3 49 3 3 3 T Seis Coe Qi 3 49 3 3 3 2 Inputs 42 Aa CES NR DES OE arate laws a 3 49 2592922 OUMU S dad RU 3 49 3 3 3 4 Fault MESSages 2 e SW ce 3 49 3 3 4 Procedure void init env void 0 3 49 3 3 4 1 Description an s ektseneciventhhveR ph oad PERE te hes 3 49 23 942 Inputs eret AGE She eae AAS Gs ee SG 3 49 et e o ERE 3 49 3 342 Fault messages eR EIE ERE CORE espe s 3 49 3 3 5 Procedure void print env void 3 50 3 3 5 2 Description eu er UE RR ESQ ete RP 3 50 3 3 5 2 eee peo eee ates Pak MELEE MENS 3 50 9 9 5 3 Gpttttttt 3 50 3 3541 Fault messages b ale oe es Ces dle dhe EU C XR eus 3 50 3 3 6 Procedure void extract_auth void
87. er Release 1 0 Software User Manual protocol specification for Field Device Web Server OPTION Value Sine Value vec p RECUP 2 JURE MODULE tree DECLARE step path tree tTree SYN END tree E MODULE Params DECLARE rhs type int SYN IValue int SYN RValue float SYN Name pchar SYN type 0 IValue 0 RValue 0 Name NULL END Params Figure A 1 Context free grammar for Parser module Page 8 Field Device Web Server Release 1 0 Software User Manual ALS 53424 a en HTTP protocol specification for Field Device Web Server 2 LEXICAL GRAMMAR OF TOKENS OF HTTP REQUEST The following text represents the listing of lexical specifications of the Scanner module see chap 3 3 2 2 generated by the Rex processor 6 EXPORT X include Position ifdef _ cplusplus t include env_class h felse include env var h fendif include rMemory h INSERT tScanAttribute GLOBAL define yyInitBufferSize 1048 define yyInitFileStackSize 1 include lt string h gt INSERT ErrorAttribute define BUFFLENGTH 50 static char OptBuffer BUFFLENGTH static unsigned char RecoverOption char InpStr if strcmp InpStr REFERER 0 return optReferer if strcmp InpStr CONNECTION 0 return optConnection Sierae MON Gano aa 0 return optHost if strcmp InpStr FORWARDED 0 r
88. es The routine returns the same condition codes as described in the response composer routine see 2 2 2 5 2 2 4 Procedure unsigned short generic error report int socket id 2 2 4 1 Description This routine is provided in order to free the user from the programming burden required for implementation of the error reporting phase in the basic server loop introduction see 2 1 2 2 4 2 Inputs The only input to the routine provides the socket identifier through which the server is communicating with the remote client 2 2 4 3 Outputs The output generated by the routine reflects the result of the sending error page operation to the client If the operation is successful the returned value is positive and non zero Negative values correspond to transmission errors detected by the socket interface layer ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 29 2 2 4 4 Operational processing This procedure prepares a standard error page which informs the client on an internal server malfunction without any particular problem description 2 2 4 5 Fault messages The negative values returned by the routine show the malfunction of the network and mean that the error page has not attained the client 2 2 5 Procedure int typed_server_prompt int socket id char res_type 2 2 5 1 Description This routine is used to generate the standard server header string used in the composition of successfu
89. esign of application specific components of the server The construction of this block is not supported by the modules of the Field Device Web Server and for this reason it is left outside of the server tier structure Page 14 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Presentation Application Wrapper Persistence Module Request Response Analyser Composer Basic Application 2 Socket Presentation Layer TCP IP Fieldbus stack layers Figure 1 3 Architecture of INTERNET based application in an Alspa F8000 equipment Taking into account these considerations the entire INTERNET based server architecture in the context of a control device can be represented by the schematic in Figure 1 3 ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 1 5 Presentation The left part of the schematic above shows the software architecture at run time which highlights mutual relationships between all building block instances The right part of the schematic shows the organisation of the Field Device Web Server module library called in the context of this project HTTPreuse at development time As shown in Figure 1 3 it is composed of five interrelated software packages set up in order to support configuration management The following figure shows the mutual relationships between the packages a Http Page 1
90. esources together with the operations to be applied to them the generic server body is in principle independent of the applications in which it is incorporated its basic elements are server engine request parser response composer and persistence module server object repository active component implementing the logistics of server object management this component structures the collection of objects which together make up the application and is in charge of assembling the elements which incorporate information generated by the application collection of application specific components elements which implement both the look and feel part of the application HTML pages compressed images Java applets ActiveX controls and its dynamics CGI scripts servlets it is important to state that these components do not do the real job of the application their role consists in conveying data between the client part and the essential application most naturally these elements are totally application dependent The analysis of the structure of an embedded server highlights yet another building block of the architecture the application wrapper This block is very often introduced into the device structure for reasons of convenience Its role consists in adapting the functional interface of the basic application to the needs of the page composition module The structure of this block is totally dependent on the basic application and on the d
91. esponses to clients requests received by the server It provides the application programmer with the possibility of choosing some implementation details while it sets others By an appropriate selection of parameter values the user can easily modify the routine behaviour and can provide his own implementation of service response operations 2 2 2 2 Inputs The routine has three parameters The first is of the int type and the two others are of the tprocessor type defined in 2 2 The semantics of the input parameters are the following int socket_id this input provides the identifier of the active socket through which the remote client is connected to the server processor scrproc this input parameter provides the reference of a routine implementing the execution process of CGI scripts processor pproc this input parameter provides the reference of a routine implementing the generation process of passive objects pages images and applets tprocessor dproc this input parameter provides the reference of a routine implementing server response when the requested object is a domain file directory Values passed by the second the third and the fourth input parameters can correspond either to the user programmed routines or to one of the specialised routines described in this manual It is important to state that the user provided routines must have the signatures compatible with the type tprocessor 2 2 2 3 O
92. essage is NULL FILE POINTER e if the input is an embedded file or embedded script node the printed message is FILE file name if the file name is provided not NULL pointer or ANONYMOUS FILE if the file name is not provided NULL pointer e if the input is an embedded directory node the printed message is DIRECTORY directory name if the directory name is provided not NULL pointer or ANONYMOUS DIRECTORY ifthe directory name is not provided NULL pointer e if the input is the tree root node the printed message is ROOT e inany other case no message is printed on the output 1 3 18 2 Inputs Reference to the node to be printed out 1 3 18 3 Outputs None 1 3 18 4 Fault messages None ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 19 Use 1 3 19 Procedure void PrintRepository tdata base struct root 1 3 19 1 Description This routine is used for debugging the VFS generated on the server machine Its role consists in visiting a VFS tree from the root till leaves and printing out the messages concerning the visited nodes The tree is visited in the depth first order The messages are printed on the standard output on the server s platform This routine calls the PrintNode routine from the same module so it inherits the messages from the latter These messages are wrapped into supplementary printouts which are Each repository printout starts with the message REPOSITORY reposito
93. eturn optForwarded if strcmp InpStr ACCEPT 0 return optAccept if strcmp InpStr ACCEPT LANGUAGE 0 return optAcceptLang if stremp InpStr ACCEPT CHARSET 0 return optAcceptChar if stremp InpStr ACCEPT ENCODING 0 return optAcceptEnc ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page A 9 HTTP protocol specification for Field Device Web Server if strcmp InpStr USER AGENT 0 if strcmp InpStr UA PIXELS 0 A UAT COLOR Siemens TNP WA OS 0 if strcmp InpStr UA CPU 0 if strcmp InpStr CONTENT TYPE 0 if strcmp InpStr CONTENT LENGTH 0 return if strcmp InpStr AUTHORIZATION 0 if strcmp InpStr PRAGMA 0 if strcmp InpStr VIA 0 if strcmp InpStr EXTENSION 0 return MAXENV 1 define yySetPosition return optUserAgent return optUAPixels 0 return optUAColor return optUAOS return optUACPU return optContIype optContLen return optAuth return optPragma return optVia return optExtension DEFAULT if EntitySize 0 EntitySize printf Scanner detected error in input illegal character code is DEFAULT MessageIl TokenPtr DEFINE letter A Za z cheme 079 id letter letter digit _ oO ae nr digit 10 13 sp 32 slash
94. field according to the following relationship result field value variant name value field type unknown not concerned undetermined c string string char c int integer int c float real float Table 3 4 Relationship between the first and second field values The existence of the structure passed as the second parameter is a pre condition for the routine s correct operation If the user does not follow this condition the routine fails and the failure mode is unpredictable 2 4 2 4 Operational processing The first phase of the routine s algorithm consists in searching a record identified by the key passed by the routine s first parameter If the search process fails the result field of the output parameter is set to 1 and the value of the second parameter is not determined If the data record corresponding to the key is found its type is determined If the type corresponds to one of three recognised types the result and the value field of the output parameter are set to the values stored within the record In the opposite case the result is set to 1 unknown and the value remains undetermined Page 3 38 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 2 4 2 5 Fault messages The routine fails when the second parameter is NULL No explicit error message is sent and this type of failure can result in the system exception provoked by access to the illegal memory address 2
95. functions is composed of seven routines described in the following table Routine InitHtmlObjectChain Parameters thtml_page_elements firstobj Description this routine initialises a list of objects and attaches the pointer passed to it by the first parameter AppedObjectToChain thtml_page_elements chain thtml_page_elements object this routine attaches the object pointed to by its second parameter to the chain pointed to by the second parameter AppendInternalObject thtml_page_elements int_obj thtml_page_elements object this routine attaches the object pointed to by its second parameter to a container object pointed to by the first parameter container objects admitted in this routine are paragraph formatted text hyperlink script and table cell AppendObjectToPage thtml_page_elements page thtml_page_elements object this routine attaches the object pointed to by its second parameter to an HTML page object specified by the first parameter AppedRowToTable thtml_page_elements table thtml_page_elements row this routine attaches the table row object pointed to by its second parameter to an HTML table object specified by the first parameter AppendCellToRow thtml_page elements row thtml_page_elements cell this routine attaches the table cell object pointed to by its second parameter to a table row object specified by the first parameter AppendInputToForm 4 3 2 2 Inputs thtml_
96. furnished within this package and can even be used separately In the normal context this does not make a lot of sense since they are designed to work together and not separately Their co operation is organised automatically by the processors of Cocktail The full interface is relatively complicated although each module has a well identified natural entry point Page 3 44 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use An advanced user can use the full interface to produce his own wrapper modules organising the PDU analysis process For the majority of typical applications it is highly recommended not to use the modules directly but to activate them via the wrapper module http_process described in 3 1 3 2 1 Module Source This module plays the role of an adapter operating between Scanner input and the source of the characters In its standard application the module adapts the Scanner to a file system of the hosting machine It handles such operations as opening and closing the files reading characters detecting end of file and handling errors This makes the Scanner module independent and lets it operate at a high level of abstraction In the context of this application the generic version of the Source module furnished with the Cocktail toolbox has to be rewritten The stream of characters in this case arrives from a network connection established via a socket interface rather then from a disk file De
97. g dynamic HTML Page D 6 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Applet Authentification procedure Base64 encoding Basic application BSD sockets Cocktail Embedded image Embedded server HTML HTTP Internet ALS 53424 Glossary Self standing Java programs whose reference is included in HTML pages applets are downloaded from the server and executed within the browser Distributed program which implements the access control to server resources based on the exchange the via network of user name accompanied by its secret password There are different types of authentification procedures the simplest one called basic authentification consists in transmission of a pair of data user name user password coded by a widely known 64 coding algorithm The basic authentification offers only rudimentary access control and is a major security loophole in the protection of INTERNET sites Coding algorithm used in the basic authentification procedure to encrypt username and password sent in HTTP Request PDU according to this algorithm the characters of the original string are by the handled elements of the standardised encoding vector The application which fulfils the principal mission of Alspa 8000 equipment e g FIP HART protocol conversion is the basic application of DI80 Berkeley Software Distribution sockets software component implementing the standard present
98. g non empty character string 1 1 1 3 Outputs The routine returns a pointer to the newly created string in the system heap The string is the clone of the input string and has the termination character 1 1 1 4 Fault messages The routine returns NULL pointer if the input string is NULL or has zero length or if the attempt to allocate the needed heap frame fails 1 1 2 Procedure void close_char char 1 1 2 1 Description This routine implements the destruction of the character string created by init_char The heap region allocated to the string is freed but not set to zero 1 1 2 2 Inputs Pointer referencing the string to be destroyed 1 1 2 3 Outputs None 1 1 2 4 Fault messages None ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 3 1 2 Module data_base_structure This module defines types and routines on which the Virtual File System is constructed The most important item defined by the module is the data type tdata_base_structure Although the file is written in ANSI C programming language its small part is directly coded in C The vast majority of the code including the data type definition is automatically generated by ast one of the processors which makes up part of the COCKTAIL toolbox see chapter 2 2 The original specification of the module is done using the ast syntax and can be found in the file data_base ast Apart from the data type definition the module p
99. g of printable characters The string is placed in a buffer and can be either processed locally in order to obtain page modifications or can be sent via the network to an http client Internet browser The routine design is based on the principle that a large enough character buffer is available for the reception of the generated character string 4 4 1 2 Inputs The routine has three inputs reference of the memory area character buffer which will store the string created by the routine initial offset with respect to the beginning of the area from which the string will be written into the buffer reference of the HTML page object to be converted 4 4 1 3 Outputs The routine returns the offset of the first byte immediately after the end of the string written in the buffer i e the first byte free in the buffer 4 4 1 4 Fault messages No error message is generated explicitly When the routine fails to convert the object the value returned is equal to the value of the second input parameter ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 73 Page 3 74 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Appendix HTTP protocol specification for Field A Device Web Server This section contains the specification of the subset of the HTTP 1 0 protocol recognised by the analysing package described in chapter 3 3 The most important restrictions with respect
100. g to the type of the record Type compatibility is determined according to the following table record type vs routine parameter c int c string any other c int float c string any other Table 3 5 Compatibility of the record type and the routine parameter The value modification changes the type of the data record when compatibility is set to no It is important that the third routine parameter references an existing variable having the right type If the user does not respect this condition the routine fails and the failure mode is platform dependent If the key value does not specify any existing record the routine attempts to create the new data record and sets its type and value according to input parameters The returned result corresponds to the type of newly created record If the attempt to create the new record fails the routine returns the 1 value ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 39 2 4 3 5 Fault messages The routine fails when the third parameter is NULL No explicit error message is sent and this type of failure ends up with the system exception provoked by the access to an illegal memory address 2 4 4 Procedure char get_first_key void 2 4 4 1 Description The purpose of this routine is the identification of the data record key values in the internal table 2 4 4 2 Inputs None 2 4 4 3 Outputs The routine returns a refere
101. g via the request PDUs The data arriving in the server in HTML form are structured as a series of name value pairs These pairs are extracted from the request PDU by the parsing procedure and are placed within the table managed by the current module The extracted data can have one of three formats integer numbers floating point numbers or character strings The module provides the following routines init data base initialises tables which hold the data et db data retrieves a value from data tables set db data sets a value in data tables et first key returns the name of the first variable stored in the tables et next key returns the name of the next variable following the one passed by the parameter These routines provide access to data stored in the table structure which is opaque to the user The user retrieves and sets the values of the data record by identifying it via its key which is a printable character string The identification of a data record via its key is unambiguous since the internal mechanisms of the module guarantee the uniqueness of the data key value within the tables In order to program the retrieval and storage of data in the internal tables the module exports the data type tdb result defined as follows typedef struct tagdb result int result union char string int integer float real value tdb result This type is used especially by get db data and set db data
102. generated The reason for the failure can be two fold the node referenced by the path object does not belong to the tree in this case the routine returns the NULL pointer the search process was stopped at a stage because the presented credentials were not compatible with the authorisation required at that stage in this case the routine returns the pointer to an object of the access list kind ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 13 1 3 8 Function tdata_base_struct SearchNodeInWidth tdata base struct root pchar name 1 3 8 1 Description This function looks for the node of a given name string pointed by the second function parameter in the VFS tree referenced by the pointer to its root first function parameter The result of the search is either a node reference or a NULL pointer The search process is based on a width first algorithm 1 3 8 2 Inputs The routine has two parameters root pointer to an existing root node of a VFS tree repository if this pointer is equal to NULL no search is initialised 9 name pointer to a character string which identifies the node within the VFS tree 1 3 8 3 Outputs The routine returns NULL pointer if the node corresponding to the name was not found In case of success the node reference is returned 1 3 8 4 Fault messages NULL pointer signifies the search failure or NULL tree reference 1 3 9 Function data base
103. he loop described previously Their descriptions can be found in 2 2 and 3 1 The application programmer using this software is free to develop his own procedures implementing the basic loop stages The only constraint imposed on this development is the signature of such routines as described in the following sections Both routines provided in the package implement this basic loop with more or less flexibility left to the application programmer or in other terms the application programmer is required to do more or less programming 2 1 1 Procedure void server_loop unsigned short port_nr tcallback analyse_routine_ref tcallback response routine ref tcallback error report ref tcallback cleanup routine ref 2 1 1 1 Description This routine which implements the basic server loop described in the introductory section provides the application programmer with the possibility of choosing the implementation details By an appropriate selection of parameter values the user can easily modify the behaviour of the server operation and can build his own implementation for each processing stage of the server 2 1 1 2 Inputs The routine has five parameters The first is of the unsigned short type while the others are of the tcallback type which is exported by the module The definition of the type is as follows typedef unsigned short tcallback int The semantics of the input parameters are the following unsigned short port nr this inp
104. hyperlink name pchar string of characters containing the object s name value pchar string of characters which will be displayed on the button onClick pchar string of characters containing the name of script activated by the click on the button hidden name pchar string of characters containing the object s name value pchar string of characters attributed as the object s value name pchar string of characters containing the object s name value pchar string of characters which will be displayed on the reset button submit name pchar string of characters containing the object s name value pchar string of characters which will be displayed on the submit button name pchar string of characters containing the object s name value pchar string of characters displayed in the object at page activation size unsigned char height of the object maxlength unsigned char maximum length of the object textarea name pchar string of characters containing the object s name value pchar string of characters displayed in the object at page activation unsigned char height of object in rows unsigned char pchar width of objects in columns string of characters containing name of radio button group pchar string of characters which gives the name of the particular element of the group
105. icated theory is now a well developed technology It uses well defined algorithms easily mastered by the technique of automatic program generators known as compiler compilers The same technology can be adapted to the development of PDU analysing modules in this package The technique used here is based the tools provided by Cocktail 5 Compiler Compiler Toolbox Karlsruhe which is a collection of co operating software tools aimed at automation of development of high efficiency compilers The use of Cocktail tools makes it possible to derive the source code of some server software modules from their formal specification Any Cocktail based front end is composed of a three stage processing process structure of incoming PDU is analysed by Parser module which is automatically derived from PDU grammar following the specification from 10 operation is facilitated by Scanner module which transforms the incoming character stream to a stream of tokens groups of characters forming composites such as separators identifiers numbers etc the structure of tokens is also specified by a formal description Scanner is adapted to source of character stream by Source module the existence of this module makes the operation of Scanner and Parser independent of the origin of the character stream this module although furnished by Cocktail in its basic version has to be implemented in this package The three modules listed above are
106. in 4 2 1 The semantics of the parameters belonging to the second and third group unsigned char nr of objand is straightforward and common to all routines On the contrary the parameters of the first group vary in number and in significance from one routine to another For this reason they require a more detailed description contained in the following table Routine Parameter Parameter types Description create hyperlink pchar ref pchar target unsigned char isref unsigned char nr of obj ref pchar URL of objects referenced by the link target pchar target for displaying object referenced by ref attribute isref unsigned char flag which when set signifies that the object is a hyperlink and when reset means that the object is an anchor create paragraph pchar align unsigned char nr of obj align pchar alignment style of the paragraph language pchar create formatted text pchar colour unsigned char size unsigned char bold unsigned char blink unsigned char style unsigned char nr of obj colour pchar font colour denomination size unsigned char font size ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 65 Use Routine Parameter Parameter types Description bold unsigned char flag setting the bold font blink unsigned char flag setting the blink mode of font style unsigned char number of style defined by HTML
107. in each request ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 43 The standard mode of operation for this routine provides the possibility of printing out on the standard output the results of environment synthesis as well as error messages detected by the parsing routines This possibility can be eliminated by an appropriate choice of the compilation option This option consists in defining the yySilent symbol during compilation of the module 3 1 3 5 Fault messages In its normal mode of operation the routine signals on its standard output the detection of syntax errors by the message Parser Error count n If n is different from 0 syntax errors are detected If the compilation option enabling the printout of syntax errors is inhibited no error messages are generated 3 2 Syntax Analysing modules One of the fundamental functions of the server software consists in analysing and extracting information from the incoming HTTP PDUs which arrive via network in the form of character streams The PDUs have a regular structure which can be described by a context free grammar The formal description of this structure can be found in the official specification 10 The function of analysing character streams is a well known design pattern implemented for example by the front end modules of programming language compilers scanners and parsers Producing compiler front end modules although based on sophist
108. in the processor memory and in access to a version of the socket presentation interface of the TCP IP network In principle the software is independent of the type of socket implementation and operating system Text compilVFS Look and feel Organisation C C ompile e Links with application Figure 2 1 Development process for an embedded server application ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 2 1 General information The generic modules provided by the HTTPreuse library are the most complex part of the server tier application Despite this fact the application developer tends not to see them in the process of application development His attention is naturally focused on five aspects of the application which are application start up a set of operations activated before the server loop is bootstrapped these operations initialise other application components their implementation is done manually by assembly of parts from HTTPreuse packages embedded site organisation this part of the application concerns the design of the Virtual File System VFS of the server tier the VFS holds the references of all objects which are part of the site and provides the search mechanism for server objects pages applets images and CGI scripts the application developer constructs this part of the embedded site by using the routines from the package described in
109. is as follows 1 0 200 OK lt cr gt lt f gt Server FIPWEB 0 9 lt Cr gt lt f gt Content type text html lt cr gt lt f gt lt Cr gt lt lf gt 2 2 5 5 Fault messages The negative values returned by the routine show the malfunction of the network and mean that the header string has not attained the network The output value set to 1 may also mean that the NULL string was routed via the second input parameter Page 3 30 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 2 3 Module Sockinterf The purpose of this module is to provide the routines which directly use network oriented services with an interface independent from the type of the stack used on the implementation platform The interface exported by this module wraps the basic calls to a socket type network interface Providing this interface porting the whole software from one communication platform to another requires only re implementation of this module The module provides the following routines initsockets initialises socket layer passivesocket creates the passive server type socket waitforconnection waits for incoming connection requests on a secondary socket closestream closes the passive socket sockprintf formatted write to socket vsockbinsend binary write to socket sockreadf read from socket peeraddrstr identification of the addre
110. java 5 script 6 c dir 4 corresponds to the directory file script exec tscript pointer to a sub routine which corresponds to the script next tdata base struct reference to an adjacent node file or directory at the same level of the VFS Table 3 2 Non Abstract object attributes Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use Object name Attribute name Attribute type Description pchar pointer to the character string storing the name of the step in the path tdata_base_struct reference to the next path record if this field is positioned to NULL the current step is the last access_list user pchar pointer to the character string storing the name of the user password pchar pointer to the character string storing the name of the password corresponding to the user name next tdata_base_struct reference to the next access record if this field is positioned to NULL this means the end of list Table 3 2 Non Abstract object attributes continued As it was stated above the user of the Field Device Web Server library is not supposed to manipulate directly the data type specified above The majority of operations are encapsulated by the programs grouped in the modules of this package and in the package data_base_processing 1 2 2 Function tdata_base_struct Makedata base struct unsigned char Kind 1 2 2 1 Description Thi
111. key void 3 40 2 44 1 Description 11 22 2 4 3 40 254 427 In DUUS eot dod scd recte qtd dee Rid GL SE ge 3 40 24 482 Outputs cecus es Per 3 40 2 444 Fault MESSAGES c ue m beoe lea eR n ra ied I en e SA prt eR 3 40 2 4 5 Procedure char get next key char 3 40 245 Description REIR ex Ed AA 3 40 2 4 5 2 Inp ts 2 isi eis T eit eee nee eee 3 40 DAS Se Euer 3 40 Faule messages deat TO aM tale iss 3 40 3 PACKAGE HTTP 5 5 3 41 3 l Module http scc pre 3 42 3 1 1 Procedure void InitParser void 3 42 3111 Description cea Wu e eee eniin 3 42 S 1 12 6 3 42 2515159 Qutputs He de Dg le CLP tice ote VP een Soe 3 42 ZELIA Fault messages seo rre n RPG OR ER Den 3 42 3 1 2 Procedure unsigned short EndParsing int socket id 3 42 3 12 12 D scriptiot reco REC a LED 3 42 3 1 2 2
112. l response PDUs returned by the server to its remote clients It is strongly recommended to use this method of server identification in any user provided routines 2 2 5 2 Inputs The first input parameter provides the identifier of the socket via which the server is communicating with the remote client The second input is a character string which identifies the type of resource requested by the client 2 2 5 3 Outputs The output generated by the routine reflects the result of the operation of sending the header string to the client If the operation is successful the returned value is positive and non zero Negative values correspond to transmission errors detected by the socket interface layer 2 2 5 4 Operational processing At first the routine tests whether the value of the second input parameter is equal to NULL If this is the case the execution terminates and the result 1 is returned to the caller If the value is different from NULL the execution continues The next step consists in analysing the contents of the string passed via the second input parameter If the string pointed to by the second parameter is gif of jpeg the generated server header is as follows HTTP 1 0 200 OK lt cr gt lt if gt Server FIPWEB 0 9 lt cr gt lt lf gt Content type image gif lt cr gt lt f gt lt Cr gt lt lf gt If the string pointed to by the second parameter is different from the values indicated above the server header
113. llowing table describes the parameters of each group function mame e dem BuildHtmlPage BuildHtmlImage BuildHtmlTable BuildHtmlTableTitle BuildHtmlForm title pchar character string containing page title bg image pchar character string containing URL of background image bg colour pchar background color code meta refresh unsigned char value of refresh period in seconds meta url pchar character string containing url of replacement page obj list source thtml_page_elements pchar pointer to the list of objects contained within the page character string containing URL designating location of virtual file which stores the image alt character string which is displayed when image is pointed to by cursor width unsigned char width of the image height unsigned char height of the image in pixels border objects unsigned char thtml_page_elements width of the image border in pixels pointer to the list of table rows title thtml page elements pointer to the table title object border unsigned char width of table s border in pixels spacing unsigned char cell spacing in pixels padding unsigned char cell padding in pixels width unsigned char relative table width in bg color objects pchar thtml page elements background color code pointer
114. ls the routine exits and the server loop is not started verifies the values of input parameters corresponding to the references of the routine implementing the four phases of server operation parameters 2 3 4 and 5 of the type tcallback if a parameter value is set to NULL the corresponding phase of the server loop is implemented by the predefined routine according to the following table Server loop phase Analysis Corresponding Predefined Routine ParseFromSocket Implemented in module http process 3 1 Error reporting generic error report senback 2 2 Response generation generic sendback routine sendback 2 2 Loop closing EndParsing http process 8 3 1 Table 3 3 Server loop phase corresponding routine and module The loop is started after the successful termination of the initialisation phase and in principle never ends without external intervention This intervention is possible since the loop is controlled by an exported variable unsigned short continue server The application programmer can implement the server stopping routine by setting this variable to 0 2 1 1 5 Fault messages None 2 1 2 Procedure void server boot unsigned short nr 2 1 2 1 Description This routine implements the basic server loop without providing the possibility to choose implementation of the server loop phases By using this routine the application programmer can only
115. n unsigned char version of HTTP protocol used 0 or 1 minor version unsigned char release of HTTP protocol used 9 0 1 environment MaxEnv char table of strings which store the values of options extracted from the request see table below resource name NLEN char string holding the name of the requested resource its maximum length is 80 in this software release resource type NLEN char string holding the extension suffix qualifying the requested object in this implementation the following extensions are significant htm html for HTML pages gif jpeg for images class for Java applets and cgi for scripts lack of extensions qualifies the object as directory resource category unsigned char numeric coding of object type can take on values as follows c_unknown 0 c text 1 c gif22 jpeg 3 java 4 dir 5 script 26 username char string extracted from authentification option field corresponding to user name userpass char string extracted from authentification option field corresponding to user password cgi_params MAXPAR tcgi par table of parameters managed as stack extracted from the header line of the request PDU EntitySize int value extracted from the Content Length option field corresponds to length of entity appended to body of PDU in the case of POST method server root tdata base struct entry point to part of virtual file system containing page
116. n tdata base struct base struct unsigned char Kind 3 7 12 2 T Description ded eles 3 7 3 7 125253 ee pero oes ri me exu d er PR IRA S 3 7 1 2 2 4 Fault Messages a yeh ete piede 3 7 1 2 3 Procedure void Releasedata base struct tdata base struct obj 3 8 1 2 3 1 Description x tir essa cel ee E 3 8 1 2 Function rbool data_base_struct_IsType tdata_base_struct obj unsigned char Kind 3 8 Description ole ed te Pee cee So lee vk es ev Det ee deu 3 8 1 2 4 2 Inputs reor ORES AGS ee be ERE eda PIC e TES 3 8 1 2 453 Outputs 66666 3 8 124A Fault messages ep Vu RE Rel POE ee ies HR BC 3 8 1 3 Module data base 3 9 1 3 1 Function tdata base struct InitRepository tdata base struct node pchar default pchar name 3 9 L3 L T Description sere Roth CE DAI Vere cee eee eas 3 9 teet ber ree POINTE ide eer elk doe les Sees ue s 3 9 1 33 O tputS E PERSE REN ee Ra nace era 3 9 1 3 L 4 Fault messages 4 5 er eR 3 9 1 3 2 Function tdata base struct BuildDirNode pchar 3 10 1
117. nce of a character string If the data table is not empty this character string corresponds to the key value of the first data record In the case of an empty table a NULL pointer is returned 2 4 4 4 Fault messages None 2 4 5 Procedure char get next key char ref name 2 4 5 1 Description This procedure while called repetitively allows the user to obtain the list of keys of all records stored in the data table The single call provides the user with the value of the key immediately following the record whose key is referenced as the routine parameter 2 4 5 2 Inputs The only input to the routine is the character string corresponding to a key of a record within the data table 2 4 5 3 Outputs The routine returns a reference of a character string If the data table is not empty this character string corresponds to the key value of the data record immediately following the record whose key is referenced as the routine parameter If the referenced record is not found or if it is the last in the table a NULL pointer is returned 2 4 5 4 Fault messages None Page 3 40 Field Device Web Server Release 1 0 Software User Manual ALS 53424 3 PACKAGE HTTP ANALYSIS basicencoder getkey decode environment pchar method unsigned char major version unsigned char minor version unsigned char resource category unsigned short
118. nputs xime ere Io ene ee ete GH 3 23 ZELIS es t p TREE Madey Ce espe 3 23 2 1 1 4 Operational processing 3 24 2 1 1 5 Faults messages vef etre Ee ative be bee owe ER e a 3 24 2 1 2 Procedure void server boot unsigned short port 3 24 Me DESCTIPULOM tl ot ta Da UNC ar C AES au 3 24 2152 2 7 Inputs ero 3 25 212213 utputs 252 RR rate esie ede a 3 25 2 1 2 4 Operational processing 2 3 25 21 25 Fault Messages Oe ee bee Ss og Hebe ewe E UE Ere 3 25 2 2 Module Sendback 5 whoo ADR eas Bae 3 26 2 2 1 Variables exported by the module 3 26 2 2 2 Procedure int response_composer int socket id tprocessor scrproc tprocessor pproc tprocessordpro6 si deterius qt 3 27 2 22 T Description ed 6 3 27 2 2 2 2 Inputs ucc et eerie ee qu cs tA 3 27 252522 CUEDUES s tiet oq OI abad dran Re len RE Mets 3 27 2 2 2 4 Operational processing 3 27 2 2 2 5 Fault Messages syo emeei ee
119. nt implementing the principle of exploration of hypertext documents are document browsing by following the hyperlinks that included in the documents LR 1 Class of abstract grammars easy to parse by efficient analysers Parser Program which analyses a phrase of a text and states whether the structure of this phrase conforms to the rules of an abstract grammar describing the language of the phrase parsers are essential parts of language compilers parsers are usually hand generated automatically In this project the parser verifies the syntax of incoming HTTP request PDUs and co operates with programs which compose the response PDUs PDU Exchanging between communicating parties during service implementation in the Internet communication model there are exist two classes of PDUs request PDUs sent by the client and response PDUs furnished by the server Portable TCP IP stack Set of co operating software components which implement the specifications of TCP and IP protocols in a way making them independent of the underlying data link the version of the portable stack used in this project can be used indifferently on WorldFIP and on Ethernet links the stack includes also the routing function Program which prepares the efficient operation of the Parser by organising the input stream of characters into aggregates called tokens scanner are rarely hand written in Scanner the majority of cases they are generated by specialised tools like Jex from
120. nt process for an embedded server application 2 1 Figure 2 2 Detailed view of embedded software application 2 3 Figure 3 1 Module relationship within the package VFS Generation 3 2 Figure 3 2 Module relationships within the package Servengine 3 21 Figure 3 3 Flow diagram of the basic server loop 3 22 Figure 3 4 Flow diagram of the response composing routine 3 28 Figure 3 5 Module relationships within the package HTTP Analysis 3 41 Figure 3 6 Module relationship within the package HTML GENERATION 3 55 Figure 1 Context free grammar for Parser module A 8 Figure A 2 Lexical specifications of Scanner module 12 Figure B 1 Structure of the repository skeleton B 2 Figure B 2 Example of skeleton constructing routine B 3 Figure B 3 Virtual File Tree 222222 bi IN GW OS ecc qr RR E eR ER RE EN Ee i B 3 Figure C 1 Module representing the code of an embedded image shown within the comment C 1 Figure D 1 View of the page from the
121. ntents of this string should strictly observe the following syntax step1_name step2_name step_name stepn_name 1 3 16 3 Outputs The function returns the reference of an object of the path kind The path object is created dynamically on the system heap 1 3 16 4 Fault messages The NULL pointer is returned when the input string is NULL or when it does not observe the imposed syntax No explicit textual message is generated 1 3 17 Procedure void PrintPath tdata_base_struct path 1 3 17 1 Description This routine serves to debug server applications Its role consists in printing on the standard output the character string which represents the path object provided as input The printout has the following syntax step1_name step2_name step_name stepn_name 1 3 17 2 Inputs The unique input of the function is the pointer to the path object 1 3 17 3 Outputs None 1 3 17 4 Fault messages If the input does not reference a valid object of the path kind the routine does not print anything Page 3 18 Field Device Web Server Release 1 0 Software User Manual ALS 53424 1 3 18 Procedure void PrintNode tdata_base_struct node 1 3 18 1 Description This routine serves to debug on server applications Its role consists in printing the data describing the input object on the standard output The format of printed information is as follows e ifthe input is the NULL pointer the printed m
122. objects of the thtm1 page elements type Page 3 64 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 4 2 1 1 Description The following table contains the description of the routines Routine Description create_hyperlink creates a hyperlink object and fills it in with a set of n objects passed by the last n routine parameters create_paragraph creates a paragraph object and fills it in with a set of n objects passed by the last n routine parameters create_script creates a script object and fills it in with a set of n objects passed by the last n routine parameters create_formatted_text creates a formatted text object and fills it in with a set of n objects passed by the last n routine parameters make html form creates a form object and inserts into it a set of n objects passed by the last n routine parameters create table cell creates a table cell object and inserts into it a set of n objects passed by the last n routine parameters create table row uchar creates a table row object and inserts into it a set of n table cell objects passed by the last n routine parameters append rows to table inserts into an existing empty html table object a collection of n rows passed by n last parameters Table 3 10 Routine description 4 2 1 2 Inputs The signature of the functions from the first group reveals the regularity of the parameters mentioned
123. of type kembedded file 1 2 4 2 Inputs The first input parameter references the object the second provides the type to be checked with 1 2 4 3 Outputs The function returns 1 when the object is of the specified type 0 when it is not 1 2 4 4 Fault messages None Page 3 8 Field Device Web Server Release 1 0 Software User Manual ALS 53424 1 3 Module data base processing This module is composed of twenty one procedures which allow the user to create and handle the objects of the Virtual File System without requiring deep insight into its data structures Although the procedures are compiled from the text in ANSI C programming language none of them is directly coded in C The code is automatically generated by puma one of the processors which is part of the Cocktail toolboxs see chapter 2 2 The original specification of the module is done using the puma syntax and can be found in the file data base puma Despite this programming technique the user interface to the module observes the ANSI C syntax Within these nineteen routines fourteen serve for run time VFS handling while five of them are used mostly in debug or test mode Among sixteen directly usable procedures eleven manipulate Virtual File System nodes files scripts directories repositories one handles authorisation installation and two process file reference elements access path and extension string Apart from the routines mentioned above the mod
124. ollection of software routines to be used by an application designer As such it does not have a well defined and unique start up procedure per se It provides only the elements to be used during the start up phase of the application developed with the use of this software The recommended calling sequence for initialisation of an embedded server application is as follows 1 Initialise network interface and system support such as memory management operations 2 Initialise VFS 3 Initialise persistence component 4 Initialise user application interface 5 Bootstrap the server execution loop The server execution loop itself contains an initialisation sequence which is either provided in the standard version of the loop or should be developed according to the design of the customised version of the server engine 3 2 Stop procedure For the reasons evoked in the previous section this software does not provide an explicit stopping procedure The other reason for this situation is the fact that the possibility of stopping an embedded server is not a commonly required feature However such a possibility exists since the module providing the server engine routines gives access to the variable which controls the server loop see chapter 3 2 1 This design feature provides the possibility of server stopping and restarting ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 2 5 General information Page 2 6 Fi
125. on errors 2 3 7 Procedure int sockreadf int sock id char buffer int size 2 3 7 1 Description This routine is a wrapper of the synchronous recv operation 2 3 7 2 Inputs The routine has three inputs sock id socket identifier buffer pointer to the buffer which receives the characters from the socket size length of the buffer 2 3 7 3 Outputs The output provides the result of the reception from the socket It gives either a number of characters received via the socket or an error code resulting from the failure of the operation 2 3 7 4 Fault messages The operation failure is reported by the value returned by it In the case of successful reception the result is positive and corresponds to the number of characters sent Negative or zero values correspond to the reception anomalies ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 35 2 3 8 Procedure void peeraddrstr char buffer 2 3 8 1 Description This routine recovers the distant peer address retreived previously called the waitforconnect routine 2 3 8 2 Inputs Reference of an existing character buffer ready to receive the remote user address in the form of a character string 2 3 8 3 Outputs None 2 3 8 4 Fault messages None Page 3 36 Field Device Web Server Release 1 0 Software User Manual ALS 53424 2 4 Module data_base_module This module handles the persistence of data arrivin
126. one correctly In any other case the routine returns NULL ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 15 1 3 11 4 Fault messages If the input parameters are incongruent or if the referenced node cannot be found the routine returns NULL No explicit textual message is generated 1 3 12 Procedure void InstallAuthorisation tdata_base_struct realm pchar username pchar password 1 3 12 1 Description This procedure provides the means of configuring access control to a VFS tree or to an embedded directory VFS sub tree The restricted VFS region is referenced by the first parameter of the routine while the second and third parameters represent the security attributes stored in a record verified by the Find Node procedure 1 3 12 2 Inputs The function has three parameters realm pointer to a root of an existing VFS or to an existing tree node of the embedded directory kind if this pointer is equal to NULL the operation has no effect and the function retums NULL username pointer to the string which contains the user name this parameter represent the credentials to be verified at every level of the searched tree password pointer to the string which contains the user password this parameter completes the user name in credential verification 1 3 12 3 Outputs None 1 3 12 4 Fault messages None 1 3 13 Function data base struct AppendStep tdata base struct path
127. ontaining paragraph alignment style objects title thtml page elements thtml page elements list of elements contained within the paragraph body pointer to object of title kind border unsigned char width of table border in pixels spacing unsigned char value of cell spacing parameter in pixels html table padding unsigned char value of cell padding parameter in pixels width unsigned char table width in 96 ALS 53424 a en bgcolor pchar code of background color i e FFF000 Table 3 9 Description of non abstract class attributes Field Device Web Server Release 1 0 Software User Manual Page 3 59 Use Object name Attribute name objects Attribute type thtml_page_elements Description list of row objects html form method pchar character string containing name of method applied when form is submitted POST or GET action pchar character string containing the url of the object activated on the server as the result of form submission objects thtml page elements list of objects contained with the form html objects object thtml page elements pointer to the object in the list head next thtml page elements pointer to the rest tail of the list noobject No parameters table title align pchar character string containing title s alignment style tobj thtml
128. ording to the following scheme Symbolic name attributed Kind of object designated krepository abstract object class from which are inherited all others except path and access_list kroot root of a Virtual File System tree knode abstract class from which embedded_directory and embedded_active_node are inherited kembedded_directory intermediate node in a VFS it can group other nodes kembedded_active_node abstract class of leaf nodes of VFS embedded_file and embedded_script are inherited from it kembedded_file leaf of the VFS which represents a file containing an html page an image or an applet kembedded_script leaf of the VFS designating an executable routine kpath link to a node in the VFS kaccess_list list of access control records composed of pairs username password Table 3 1 Type values and their mean In the current version of VFS there are nine types of objects divided into three groups three VFS abstract objects repository node and embedded_active_node these objects are used very rarely since they represent the common properties of other objects three classes of VFS concrete objects embedded directory embedded file and embedded script these objects represent the concrete elements of the VFS system corresponding to directories and files of a regular disk oriented mass memory system two classes of auxiliary objects path and access 115 these objects represent respectivel
129. page_elements form thtml_page_elements input this routine attaches the form input object pointed to by its second parameter to an HTML form object specified by the first parameter Table 3 15 Description of routines The routine signature has a very regular structure as it can be seen from the previous table The meaning of both parameter functions is always the same the first means container object and the second means the object to be added to the list of contained objects Only first routine is different from the others since its role consists in preparation of an object chain for further usage 4 3 2 3 Outputs thtml page elements pointer to an object of a given type 4 3 2 4 Fault messages None Page 3 72 Field Device Web Server Release 1 0 Software User Manual ALS 53424 4 4 Module html_conv_module The role of this module consists in transformation of HTML related objects to character strings ready to be transported through the network The module contains many local routines each specialised in transformation of a particular type of object The only routine accessible from the outside of the module is the Ht m1PageToString function described in the following section 4 41 Function unsigned short HtmlPageToString pchar buffer unsigned char buff_ptr thtml_page_elements html_page_obj 4 4 1 1 Description This function converts a complete well formed HTML page object into a zero ended strin
130. plication personalisation is placed on the server side which is interfaced directly with the embedded application software This configuration is at the origin of the internal architecture of the server tier which contains three functionally separate parts generic modules of the server which support HTTP protocol operation totally independent of the user application user provided modules implementing interaction mechanisms between the human operator and the embedded application software These modules contain passive data such as embedded HTML pages embedded images and embedded Java applets as well as active data such as routines generating dynamic pages or routines embedding process data into served HTML pages application wrapper modules which adapt the API exposed by the embedded application to the needs of user provided modules This architecture simplifies the development process of newly created applications Only user provided modules are to be developed for each new project Generic modules are to be totally reused for a wide range of environments and for different types of applications Wrapper modules are to be developed for each type of hosting device and reused for different applications placed in the given type of the device ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 1 3 Presentation 1 GENERAL DESCRIPTION OF DEVELOPED SOFTWARE The introductory explanation from the previou
131. plication is presented in Figure 2 1 Relationships between application components are presented in Figure 2 2 Page 2 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424 General information HTTP reuse Pages CGI script images servlets applets dynamic pages Figure 2 2 Detailed view of embedded software application ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 2 3 General information 2 ROLE OF COCKTAIL TOOLBOX One of the important functions of the developed system consists in analysing the requests incoming from the network The software package which implements this function operates as an analyser of a stream of ASCII encoded characters This makes its design very similar to the design of front end modules of programming language compilers Such modules are never programmed manually but are generated from the high level specification of the syntax of the character stream To generate the analysers one uses the software known under the generic name of compiler compilers The most eminent but not the most powerful example of such a software is the pair of UNIX programs LEX and YACC The technique of implementation of request analysers used in this project is based on the principle of automatic generation of the analysers The tools used in the project belong to the COCKTAIL 5 6 7 8 9 package which is one of the most powerful tool sets known in the area of compile
132. pointer 3 3 9 4 Fault messages No explicit fault message is generated Some failure modes are assimilated to the result of not finding the searched node In both cases the output returned is NULL 3 3 10 Function tdata_base_struct search_script void 3 3 10 1 Description This routine implements the search for an object in the VFS within the tree containing active server objects i e cgi scripts The routine has no input parameters and the search process is controlled by the values of environment variables resource_path resource_type username and userpass The search is done by the call to the FindNode routine see 1 3 7 applied to the VFS tree having the root referenced by the cgi_bin variable 3 3 10 2 Inputs None 3 3 10 3 Outputs Reference of the descriptor of the script object searched for or a NULL pointer 3 3 10 4 Fault messages No explicit fault message is generated Page 3 52 Field Device Web Server Release 1 0 Software User Manual ALS 53424 3 4 Module basicencoder This helper module implements the basic functions used to decode the incoming username password pair coded according to a base 64 algorithm The functions of this module are called uniquely within the context of the var module and serve to decode password and username variables arrived in the input PDU as a 64 coded string 64 coding is a process of replacing an ACSII character sentence by a coded chara
133. ption This routine organises the correct scheduling of operations during the phase of request PDU analysis The application programmer can use this procedure without deep insight into the details of parser operation and environment construction This procedure is proposed as a default solution for the phase of request analysis see 2 1 3 1 3 2 Inputs The only input is the identifier of the server socket connected to the client This socket receives the analysed PDU 3 1 3 3 Outputs The result returned by the routine reflects the status of the parsing process If the parsing routine accepts the received PDU the result is 1 in the opposite case the result is 0 3 1 3 4 Operational processing The procedure chains the following operations clean up of environment variables linking the active socket receiving the request to the input of the parsing routine parser initialisation parsing of the request with environment construction parser termination management of authentification The parsing process produces the following information contained in the HTTP of the request PDU requested method protocol version main version and release number protocol options requested resource name requested resource class authentification data user name and password request parameters posted data data sent via post service Not all the items listed above are found
134. q 3 42 9 1223 Es cr scel 3 42 3 1244 Fault messages nee Roten eae as GERE Ee eg 3 43 3 1 3 Procedure unsigned short ParseFromSocket int 1 3 43 31 35 Description t Lee E E ake RE dad 3 43 3 3 2 u nputs cedes oper 3 43 22193 OUMU UE n rp EU an dee ve 3 43 3 1 3 4 Operational processing 3 43 31 23 53 FMES Sagos aa A A 3 44 3 2 Syntax Analysing modules 3 44 3 21 vo eter age 3 45 322 Scanner EO NORIS 3 45 9 29 Mod le Parser 235 erret ert pdt RE ERA RAD aus 3 46 3 3 0 Module eBv SVdE o ooa rV E EUER pe TERT 3 46 3 3 1 Function char AllocTokenStr unsigned long length 3 48 33 1 1 DescriptiOn ees Sah y ces RA Re cae eyed 3 48 9 13 12 ST itech on Adres terea iso eda TOU qub Ee eL d oe e Redes 3 48 3 3 1 3 Outputs ae eee PERS 3 48 3 3 1 4 Fault messages vio Celene 3 48 3 3 2 Procedure void FreeTokenStr char tokenstr 3 48 3 3 2 T Description sh Gs ee Pe ED 3 48 ALS 53424 Fi
135. r compilers It is composed of a coherent set of processors which support the following operations rex lexical analyser counterpart of lex generates scanners four times smaller and four times faster lark counterpart of yacc among many features which make it more user friendly than yacc this processor generates parsers which are twice as fast as parsers generated by its well known predecessor for approximately the same size of code ag evaluator of attributed grammars not used here does not have any counterpart among freeware programs ast abstract syntax tree generator used here to generate the programs in the modules data base structure and html page elements puma supports tree evaluation and transformation used in modules data base processing gen tree module and html conv module The use of these tools considerably increases the speed and the quality of the development process This can be explained by the size of the source files which directly influences the ease of code maintenance Another advantage of the COCKTAIL package is the existence of a library of reusable software components which are used not only by the routines generated by the above cited tools but can also provide services to hand written programs Page 2 4 Field Device Web Server Release 1 0 Software User Manual ALS 53424 General information 3 START UP STOP FUNCTIONS 3 1 Start up procedure The produced software is a c
136. radation of the currently supported features The embedded file can be transformed into a module which is linkable with the server main program An example of such a file embedding an image in gif format is shown in the following figure extern const unsigned char aautobull2_img extern int aautobull2 img length const unsigned char aautobull2 img 0x47 0x49 0x46 0x38 0x39 0x61 0x0c 0x00 0x0c 0x00 0xb3 OXE 0x00 OKEE OX f 0x66 Oranian 0 505 Ose O00 Oxee 0 O00 0 0 Ose Weel 10 00 288 0x00 0x99 0x99 0x00 0x99 0x66 0x00 0x66 0x99 0x00 0x66 0x66 0x00 0x33 0x66 0x00 0x33 0x33 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x21 0 9 0x04 0x01 0x00 0x00 0x04 0x00 0x26 0x00 0x00 0x00 0x00 0 0 0x00 0x0c 0x00 0x00 0x04 0x42 0x90 0xe8 0x49 0x6b Oxbb 0xb7 0x92 0x86 0x42 0x10 0x47 0x43 0x35 0x02 0xed 009 0593 0x21 0x6e 0x88 0x19 0 0 0 83 0 22 0x92 0x81 0x39 0x08 0xe6 03 98 0xee Oxde 0x57 0x14 0xba 0xdd 0x46 0x40 0x84 0x19 0x14 0x0b 0xd9 0 0x00 Oxlb 0x16 0x50 0 0x31 0x28 0x18 0x12 0x48 0xe9 0x48 1 0x53 0x68 0x2d 0x98 0x95 0x24 0x02 0x00 0x3b int aautobull2_img_length 149 re Figure C 1 Module representing the code of an embedded image shown within the comment ALS 53424 Field Device Web
137. rovides the implementation of three auxiliary functions as described below 1 2 1 Definition of tdata_base_structure data type The definition of tdata_base_structure follows the regular scheme as below typedef union yobj type name 1 obj type name 1 yobj type name 2 obj type name 2 yobj type name n obj type name n tdata base structure The type is then a pointer to a union which groups the structures Each variant of the union designates the type of object belonging to the VFS These types have a very consistent construction as shown in the schematic below typedef dll obj desc tKind unsigned char typedef dll obj desc tKind Kind dll obj desc tNodeHead yyHead object attribute fields yobject name The first field of each object is the tag Kind which identifies the object class The second field of the record is used by the VFS internal modules to manage the pool of objects The rest of each structure is composed of the series of object attribute definitions In principle the user should not modify these attributes manually and should rely on the set of routines furnished by this module as well as by the module data base processing Page 3 4 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use The type of the first field of the structure is the sub type of unsigned char and takes on the values from to 9 The type values are redefined as a set of symbolic constants acc
138. ry name STARTS if the repository name is known or REPOSITORY unnamed STARTS if the repository name is not known This message is followed by the series of printouts for visited nodes For the repository root and for each embedded directory node the message generated by the PrintNode routine is completed by the line representing the contents of the access list ACCESS LIST IS EMPTY if the access list is empty pointer set to NULL or ACCESS LIST followed by the series of pairs of identifiers representing the authorised user and its password if the access list is not empty The repository printout ends with the message REPOSITORY repository name ENDS if the repository name is known or REPOSITORY unnamed ENDS if the repository name is not known 1 3 19 2 Inputs Pointer to the root of a VFS tree 1 3 19 3 Outputs None 1 3 19 4 Fault messages If the input node is NULL no message is printed on the output Page 3 20 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 2 PACKAGE SERVER ENGINE The package regroups the modules which implement the operation of the server on the global level such as management of server s main loop adaptation to the network management of response generation and management of request s persistence It is composed of four modules module servengine regroups the routines implementing the main server loop module sendback is in charge of servicing
139. s images and applets cgi bin tdata base struct entry point to part of virtual file system containing cgi scripts resource path tdata base struct path to object reference see 1 2 1 Page 3 46 Table 3 6 Environment data structures Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use The current version of the module is able to store up to thirty two option values The request analyser recognises and retrieves the values of nineteen types of option fields most frequently found in the request PDUs These options are listed in the following table Value Option type Symbolic value implemented implemented 1 Referer optReferer 2 Connection optConnection 3 Host optHost 4 User Agent optUserAgent 5 Forwarded optForwarded 6 Accept optAccept 7 Accept Language optAccepLang 8 Accept Charset optAcceptChar 9 UA Pixels optUAPixels 10 UA Color optUAColor 11 UA OS optUAOS 12 UA CPU optUACPU 13 Pragma optPragma 14 Accept Encoding optAccepEnc 15 Content Type optConType 16 Content Length optConLen 17 authentification optAuth 18 Via optVia 19 Extension optExtension Table 3 7 Common types of option fields Option strings stored in the environment table can be used in the user provided cgi scripts For the non recognised options the retrieved values are stored in the 31 element of the table In the c
140. s replaced by a blank character every group of three symbols composed of leading followed by a two digit hexadecimal number is replaced by the ASCII character whose code corresponds to the hexadecimal number If the input string is NULL the routine returns NULL In any other case the routine returns a string created on the system heap 3 3 8 2 Inputs The only input is a null terminated string extracted from the request PDU 3 3 8 3 Outputs Reference to a heap allocated string containing the decoded version of the input string 3 3 8 4 Fault messages No explicit fault message is generated however a NULL string is output when the input string is NULL or when heap frame allocation fails ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 51 3 3 9 Function tdata_base_struct search_object void 3 3 9 1 Description This routine implements the search for an object in the VFS within the tree containing passive server objects i e directories pages images and applets The routine has no input parameters and the search process is controlled by the values of environment variables resource_path resource_type username and userpass The search is run by the call to the FindNode routine see 1 3 7 applied to the VFS tree having the root referenced by the server_root variable 3 3 9 2 Inputs None 3 3 9 3 Outputs Reference of the descriptor of the object searched for or a NULL
141. s routine creates in the system heap an object of the kind specified by the unique parameter and returns the reference to this object 1 2 2 2 Inputs The input parameter specifies the kind of object to be created its value should correspond to one of the constants specified in Table 3 1 1 2 2 3 Outputs The returned value is a reference of the newly created object pointer to the object if the creation succeeds 1 2 2 4 Fault messages In case of failure the procedure returns the NULL pointer No explicit textual message is generated ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 7 1 2 3 Procedure void Releasedata_base struct tdata_base_struct obj 1 2 3 1 Description This routine destroys the object referenced by the input parameter The heap area occupied by the object is returned to the system 1 2 3 1 1 Inputs The input parameter references the object to be destroyed 1 2 3 1 2 Outputs None 1 2 3 1 3 Fault messages None 1 2 4 Function rbool data_base_struct_IsType tdata_base_struct obj unsigned char Kind 1 2 4 1 Description This routine checks whether the object referenced by its first parameter is of the type designated by the second parameter The object is considered to be of the given type in two cases it belongs to a sub type of the specified type example root is of type krepository itis strictly of the specified type example embedded file is
142. s section shows that there are two conditions for setting up INTERNET technology inside the automation cells enhancement of fieldbus protocol stack with the TCP IP layer the cell front end process computer must in this case play the role of IP router placing the server part of the distributed application in a device within the cell this device should be equipped with sufficient processing power and should have enough memory to host the server modules in many cases the server is placed in the cell front end computer The software structure of the device hosting the server will thus be composed of two functionally specialised parts the essential application doing the real job of process control this application is in principle independent of the INTERNET the server tier from Figure 1 2 adapting the interaction mode between the generic thin client and the essential application Since elements of automation cells do not dispose of large computing resource reserves it is necessary to develop the components allowing the user to construct with ease small portable and modular server tiers In most cases every server tier is composed of three basic elements generic server body principal active component which loops heaping to the incoming service requests and processes them request processing consists in parsing the PDU syntax recovering environment variables in order to support CGI operations identifying requested r
143. s within the page skeleton can be implemented either by the direct modification of HTML code of the skeleton or in some cases can be handled during edition of the skeleton on the specialised tool The following example shows the piece of HTML code which represents the page skeleton with an inserted variable component ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page D 1 Serving dynamic HTML The HTML page must be generated so as to resemble the page in Figure D 1 with the possibility of varying three elements E ba Er rami ber l epi l PEJE Pete Dem a rar E de a dau rip mE pie Lea ge Dee gt eg ae d M Figure D 1 View of the page from the example 1 Error message 1 shown by the upper frame 2 Partof text 2 on the left button shown by the lower frame 3 Operation corresponding to a click on the left button invisible in the figure The analysis of the problem shows that it is enough to provide the page template with three variable elements all three of string type The page template will be laid out as in Figure 3 6 Three formats corresponding to three variable parameters are shown in Figure D 2 as white fields html head lt title gt PASSWORD TESTS title lt head gt lt body gt script Language JavaScript fun
144. spite this fact the standard interface composed of three routines is to be maintained in its original form in order to keep the mode of operation of Scanner and Parser modules unmodified The interface functions are in principle never called directly by the software user Here follows their description int BeginSource char filename this routine redirects the Scanner input receiving the analysed character string from the standard input to a different source in this case to an opened TCP IP socket the type of its input parameter a character string signifying the stream symbolic name is adapted to its original implementation in this case the socket identifier of int type converted to character string i e to char type is to be used this parameter is passed from the user application to the routine indirectly via the call of the Scanner interface function BeginFile in the typical application even this call is not provided by the user who activates it by calling the wrapper routine ParseFromSocket 9 void CloseSource int file id this routine terminates the analysis from a character stream by closing it it is never called directly from the application software in a standard application the routine is activated from the call to EndParsing routine which calls the Scanner interface function CloseFile the routine s input parameter has meaning only in the context of its calling environment i e inside the Scanner int GetLine int file
145. ss of the remote peer In its current version the module adapts the rest of the software to three networking packages the SockApi package of Alstom the BSD Sockets implementation of SUN Solaris and the Winsock2 socket implementation of Microsoft 2 3 1 Procedure int initsockets void 2 3 1 1 Description Some implementations of socket API like Microsoft s Winsock2 require an explicit initialisation procedure This routine provides the wrapper of the initialisation operation for such implementations For the portability purposes itis recommended to call this routine any time when network operation should be restarted 2 3 1 2 Inputs None 2 3 1 3 Outputs The routine returns an integer type result which can be only one of two values 1 or 1 A successful initialisation operation corresponds to the value 1 2 3 1 4 Fault messages A returned value equal to 1 signifies the routine s failure ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 31 Use 2 3 2 Procedure int passivesocket unsigned short port_nr char type int quelen 2 3 2 1 Description This routine provides the wrapper for the series of operations which lead to the creation of a server socket bound to an IP address of the platform completed by the port number provided via input parameters When the routine returns successfully the socket is created and ready to accept the external connections 2 3 2 2 Inputs The routine
146. struct GetNodeRef tdata base struct root tdata base struct path 1 3 9 1 Description This function checks whether a path provided as the second function parameter corresponds to a node in a tree referenced by the first function parameter 1 3 9 2 Inputs The routine has two parameters root pointer to an existing root node of a VFS tree repository if this pointer is equal to NULL no search is initialised path reference of an object which represents the path to be followed during the search process 1 3 9 3 Outputs The routine returns either the reference to an existing node or a NULL pointer 1 3 9 4 Fault messages Routine failures are represented by the NULL pointer returned The NULL result is returned in two cases either one of the input parameters is equal to NULL or the referenced node was not found No explicit textual message is generated Page 3 14 Field Device Web Server Release 1 0 Software User Manual ALS 53424 1 3 10 Procedure void ProcessNode tdata base struct node tnameproc proc 1 3 10 1 Description This routine provides the means of applying programmed processing on the node referenced by its first parameter The operation to be applied to the node is programmed in a routine which is referenced by the second parameter 1 3 10 2 Inputs The routine has two parameters 9 node pointer to an existing node of a VFS tree tree root embedded file embedded script or embed
147. t in pixels unsigned char unsigned char image maximum border width in pixels number of consecutive empty lines within the page generated by this object width unsigned char relative line width in size unsigned char line thickness in points align pchar character string containing line s align style Page 3 60 code pchar character string containing the url of applet s source file codebase pchar character string containing the url of the directory containing applet s source file Table 3 9 Description of non abstract class attributes continued Field Device Web Server Release 1 0 Software User Manual ALS 53424 Object name hyperlink Attribute name alt Attribute type Use Description character string containing the alternative string width unsigned char width of area reserved for applet in pixels height unsigned char height of area reserved for applet in pixels ref pchar string of characters containing url of referenced object of the link target pchar string of characters containing reference of browser s object in which the link reference is to be displayed isref unsigned char flag set to a non zero value when the link is a hyperlink and set to zero when it is an anchor objects thtml_page_elements pointer to the list of objects contained within the
148. tack 3 create_paragraph NULL 1 lptrstack 4 lptrstack 2 create_paragraph center 1 lptrstack 3 lptrstack create_paragraph NULL 1 1lptrstack 2 lptrstack 2 create_paragraph center 1 _T lstrmess Sprincr lburt BACK ss Ustrbuti lptrstack 4 BuildValuedInput 28 SendButton lbuff lptrstack 5 BuildButtonInput backhome Home return backhome onclick lptrstack 3 create paragraph center 2 lptrstack 4 lptrstack 5 e eO make html publrc di80 param form htm 3 lptrstack ll Jprtrstack 2 dene sene lpage AppendObjectToPage lpage lptrstack 0 free lbuff return lpage Figure D 4 Example of abstract representation procedure Page D 4 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Serving dynamic HTML The data structure produced by this routine can be converted to the character string by the call to the procedure HtmlPageToString see chap 3 4 4 1 as in the piece of code below char template string ushort template length thtml page elements thepage template string malloc 4096 thepage GenHtmlPage PASSWORD TESTS 0 Your password is wrong re enter it TO FORM template length HtmlPageToString template_string 0 thepage Figure D 5 Example of HtmlPageToString routine ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page D 5 Servin
149. the composite HTML objects which contain simple ones nine classes of objects which represent active parts of an HTML form object button hidden submit text textarea three classes of objects used to form collections lists object list noobject three classes of intermediate level objects forming HTML tables table row radio reset checkbox and image html objects and table title table cell and eight classes of elementary objects representing the most frequently used HTML tags from which the embedded pages are constructed script line formatted text plaintext html image applet and hyperlink emptyline Each class whether abstract or concrete has a number of attributes the attributes for the non abstract classes are specified and described in the following table Object name html page paragraph Attribute name title Attribute type Description character string containing html page title bgimage character string containing background colour reference for the page bgname meta refresh unsigned char character string containing background image reference for the page value of meta refresh parameter in seconds meta url pchar character string containing the url of object reference being the meta url parameter objects thtml page elements list of elements contained within the page body align pchar character string c
150. the objects module sockinterf adapts the server to the network interface module data base module implements the persistence of data sent from the client via the request PDU The mutual relationships are represented by the diagram below sockinterf initsockets passivesocket waitforconnect data_base_module search table key_type last key int i string_matrix char vsockbinsend Jast_string 2 integer_matrix int tr 7 E 1 last_int peeraddrO float_matrix float IN last float int init_data_base get_db_data set_db_data get_first_key get_next_key set_pre_trigger set_post_trigger printdb sendback script_routine tprocessor page_routine_ptr tprocessor response_composer generic_error_report generic_sendback_routine typed_server_prompt servengine continue_server unsigned short server_boot server_loop stop_server Figure 3 2 Module relationships within the package Servengine One can easily observe that only three out of four modules co operate sendback servengine and sockinterf The fourth module which is in charge of implementing the request data persistence is stand alone and does not provide directly any services to the three others It is put in
151. the page template from Figure 3 6 ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page D 3 Serving dynamic HTML 2 ON LINE GENERATION OF PAGES Pages of the second category are generated by the programs which make use of routines from package HTML GENERATION see chap 3 4 These routines generate the structures of data which are the abstract representations of the HTML pages and convert them to character strings inserted into the server s response PDUs The method gives more flexibility than the one previously described since every parameter can be modified from one procedure call to another Figure D 4 shows an example of a procedure which constructs the abstract representation of the page shown in Figure 3 5 include html gen hl h include lt malloc h gt include lt string h gt thtml page elements GenHtmlPage PASSWORD TESTS O char lstrlock char lstrmess thtml_page_elements lpage thtml_page_elements lptrstack 10 char lbuff malloc 100 sprintf lbuff Xnfunction backhome onclick location s lstrlock lpage BuildHtmlPage PASSWORD TESTS NULL NULL O NULL NULL lptrstack T lbuff lptrstack 0 create script JavaScript 1 lptrstack 1 lpage AppendObjectToPage lpage lptrstack 0 lptrstack 5 create formatted text NULL 5 0 0 0 1 T PASSWORD ERROR lptrstack 4 create_formatted_text NULL 0 1 0 0 1 lptrstack 5 lptrs
152. tml page elements BuildHtmlImage pchar pchar unsigned char unsigned char unsigned char BuildHtmlTable thtml page elements page elements unsigned char unsigned char unsigned char unsigned char pchar BuildHtm TableTitle thtml page elements pchar BuildHtmlForm thtml page elements pchar pchar BuildPlainText pchar BuildApplet pchar pchar pchar unsigned char unsigned char BuildHtmlTableCell pchar unsigned char unsigned char unsigned char thtml page elements BuildEmptyLines unsigned char BuildSeparator unsigned char unsigned char pchar BuiledValuedInput unsigned char pchar pchar BuildTextInput pchar pchar unsigned char unsigned char BuildImageInput pchar pchar BuildButtonInput pchar pchar pchar BuildCheckableInput unsigned char pchar unsigned char BuildTextAreaInput pchar unsigned char unsigned char pchar 4 3 1 1 Description Each routine when successful generates an object of an appropriate kind on the system heap To do this the routines use the function Makehtml page elements from the module html page elements ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 69 Use 4 3 1 2 Inputs Input parameters of the functions convey the values of object attributes Their number and type depend on the kind of objects constructed by the function The fo
153. ts each which together form the 24 bit entity pointer to an existing character string which is supposed to receive the decoded characters offset with respect to the string s beginning starting from which the three retrieved characters are to be placed 3 4 2 3 Outputs The output corresponds to the first free place within the string from which the subsequent characters can be written this value is equal to the value of the third input parameter increased by three 3 4 2 4 Fault messages No explicit failure mode is coded The routine expects that the string referenced by the second parameter exists and that it has at least three places free in order to receive the decoded parameters If this precondition is not fulfilled the result of the procedure operation is not predictable Page 3 54 Field Device Web Server Release 1 0 Software User Manual ALS 53424 4 PACKAGE HTML GENERATION Use The package regroups the modules which provide the services related to the on line generation and handling of the embedded HTML pages html_conv_module commondef from VFS Handling HtmlPageToString html_page_elements Makehtml_page_elements Releasehtml_page_elements html_page_elements_IsType R N html_gen_hl create_hyperlink create_paragraph create_script create_formatted_text create_table_cell create_table_row
154. ts uchar Kind 3 62 42 21 Description tA DUO 3 62 4 1 22 Inputs petenda ER EE ER dere 3 62 41 25 oec ren cM qus EC bach tma als had MU leone 3 62 4 1 24 Paultimessdges oce o Res eS a 3 62 4 1 3 Procedure void Releasehtml page elements thtml page elements object 3 62 4 1 3 Te DeSCrIpliOl Ss etenim 3 62 4 1 3 2 eo e eor A SERRE EE DD a IR ace eed a 3 62 4 1 3 3 Outputs siete 66 3 62 4 1 3 4 Fault messages ies ecco eh aed Ner Sates 3 62 4 1 4 Function html page elements IsType thtml page elements object uchar Kind 3 63 4 1 4 1 Description ented Hie SPORE Re e Se Perse ore Ed 3 63 4 E42 ote edt eRPOSEROERE ERI ER HR 3 63 41 437 Outputs 4 3 63 414 4 Fault messages as is er ene re ex gr a pre a DR 3 63 4 20 Module html gen 1 3 64 4 2 1 Routines generating container objects 3 64 AD AA UR AL eee d te 3 65 ARI uInputs creer Bese EE Ae ea a here rS DERE E TS 3 65 4 2 13 OUtputs WEE Ern idee m DES 3 6
155. ule exports one data type which describes the type used by one of the exported routines ProcessNode The detailed description of this type can be found in the section describing the routine Process Node 1 3 10 1 3 1 Function data base struct InitRepository tdata base struct node pchar default pchar name 1 3 1 1 Description This routine creates the root of the new Virtual System Tree in the system heap It is usually the first operation in the process of building the server s repository 1 3 1 2 Inputs The routine has three inputs node reference of an existing node which becomes the first internal node in the repository if this parameter has NULL value the newly created tree will be reduced to the root node only default pointer to a character string which contains the name of the default file served when the root of the VFS tree is invoked by the http request the string should represent the name of an existing file name pointer to the string which contains the name of the newly created tree this string van be empty but some routines of this module write return fault messages 1 3 1 3 Outputs The routine returns the pointer to the newly created root node of the VFS tree 1 3 1 4 Fault messages If the node creation fails the routine returns NULL ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 9 1 3 2 Function data base struct BuildDirNode pchar name
156. ut provides the value of the TCP port on which the server will operate tcallback analyse routine ref this input parameter provides the reference of a routine implementing the incoming PDU analysis tcallback response routine ref this input parameter provides the reference of a routine implementing the generation of server s response to the request tcallback error report ref this input parameter provides the reference of a routine implementing the server reaction in case of error detected during the analysis phase tcallback cleanup routine ref this input parameter provides the reference of a routine implementing the termination phase of the basic loop Values passed by the four last input parameters can correspond either to the user programmed routines or to one of the specialised routines described in this manual It is important to state that the user provided routines have to have the signatures compatible with the type tcallback 2 1 1 3 Outputs The routine does not provide any output values ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 23 Use 2 1 1 4 Operational processing The control flow of the routine follows the diagram in Figure 3 3 In the initialisation phase the routine implements the following operations attempts to create a TCP type socket and assigns it the TCP port number passed by the first parameter of the routine if socket creation fai
157. utputs The output provided by the routine reflects the result of the response generation process In general a positive non zero result corresponds to a situation in which a server object was correctly sent to the client Such an object can correspond to a requested page image or applet to an activated script or to an error signalling page The negative or Zero result means that the response generation was not successful and that nothing was sent back to the client 2 2 2 4 Operational processing The operation of the routine follows the flow diagram shown in Figure 3 4 As it can be seen the processing is organised in three steps 1 identification of object processors First step of the routine consists in choosing between two exclusive processing threads one for CGI script activation and one for passive object transmission The processors are to be used in subsequent steps of the routine The choice is based on the values passed via the second and the third input parameter ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 27 Use If the value of the second parameter is set to NULL CGI script execution will be realised by the routine whose address is passed via the external variable send_script_routine If this value corresponds to the entry point of a user provided routine it will be used to rule script execution If the value of the third parameter is set to NULL the passive objects service pages
158. warranties of merchantability or fitness for purpose shall apply In this publication no mention is made of rights with respect to trademarks or tradenames that may attach to certain words or signs The absence of such mention however in no way implies there is no protection Partial reproduction of this document is authorized but limited to internal use for information only and for no commercial purpose However such authorization is granted only on the express condition that any partial copy of the document bears a mention of its property including the copyright statement All rights reserved Copyright 2000 ALSTOM Paris France Page 2 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Revisions Index letter Nature revision ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 Revisions Page 4 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Preface 1 PURPOSE OF MANUAL AND DOCUMENTED VERSION This manual describes the collection of software packages called in the sequel FieldDeviceWebServer lt gt Its main objective is to facilitate the design and implementation of software applications called Embedded Web Sites or interchangeably Embedded Web Servers The document contains the detailed description of the functions contained in the software packages and is considered as the reference manual for designers of the embedd
159. while the TCP UDP port number is passed via the routine s parameters If the conditions of address binding are accepted the routine continues In the opposite case an error message is issued and the routine exits 3 If the socket is of SOCK STREAM type and if binding of the socket to an address succeeds one attempts to make it listen to incoming connection requests and this call to the Listen operation makes use of the third parameter of the routine which establishes the length of the queue used for buffering the incoming requests for connection If this call succeeds the routine exits leaving the created socket passively waiting for the request for connections In case of failure an error message is produced before the routine s exit Page 3 32 Field Device Web Server Release 1 0 Software User Manual ALS 53424 Use 2 3 2 5 Fault messages In case of negative reaction from the network API this routine prints messages on the error output The messages follow a certain format but their definite shape depends on the implementation platform There are three types of messages 1 socket creation failure can t create socket platform dependent string 2 bind to address failure cant bind the socket to port nr port nr platform dependent string 3 listen activation failure can t listen to socket on port nr port nr platform dependent string 2 3 3 Procedure int waitforconnect int main sock
160. y a link to a VFS node and the list of access right records pairs of username password used to restrain the navigation in the VFS ALS 53424 Field Device Web Server Release 1 0 Software User Manual Page 3 5 Use Each object features a number of attributes The non abstract object attributes are specified and described in the following table Object name embedded_directory embedded_file embedded_script Page 3 6 Attribute name Attribute type Description pointer to a character string which stores the name of the whole VFS tree member list tdata base struct pointer to a list of sub trees of VFS tree the sub trees can be either leaves embedded files or embedded scripts or sub tree roots embedded directories access list tdata base struct pointer to a list of access records each storing a pair of character strings username password this feature provides the access control for the whole VFS tree default obj name pchar character string which contains the name of the default file served by the server when there is no resource designated by the HTTP service request URL is limited to the server TCP IP address only tdata base struct pchar reference of another tree of the VFS residing in the same server pointer to the character string storing the name of the directory member list tdata base struct pointer to a list of sub trees belonging to

Field Device Web Server Release 1.0 Software User Manual

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