/* @doc HESIOD @module hesiod.c | This module contains the defintions for the exported functions: hes_to_bind hes_resolve hes_error hes_free as well as the internal function hes_init. The hes_init function is the one that determines what the Hesiod servers are for your site and will parse the configuration files, if any are present. WSHelper DNS/Hesiod Library for WINSOCK */ /* This file is part of the Hesiod library. * * The BIND 4.8.1 implementation of T_TXT is incorrect; BIND 4.8.1 declares * it as a NULL terminated string. The RFC defines T_TXT to be a length * byte followed by arbitrary changes. * * Because of this incorrect declaration in BIND 4.8.1, when this bug is fixed, * T_TXT requests between machines running different versions of BIND will * not be compatible (nor is there any way of adding compatibility). * * Copyright 1988 by the Massachusetts Institute of Technology. See the * file for copying and distribution information. */ #define index(str, c) strchr(str,c) #include #include #include #include #include #include #include #include #include #include "resource.h" #define USE_HS_QUERY /* undefine this if your higher-level name servers */ /* don't know class HS */ char HesConfigFile[_MAX_PATH]; static char Hes_LHS[256]; static char Hes_RHS[256]; static int Hes_Errno = HES_ER_UNINIT; extern DWORD dwHesIndex; /* @func int | hes_init | This function is not exported. It takes no arguments. However it is important to understand how this works. It sets the global variables Hes_LHS and Hes_RHS which are used to form the Hesiod queries. Understanding how this works and setting up the correct configuration will determine if the Hesiod queries will work at your site. Settings can be configured by makgin source code changes and rebuilding the DLL, editing resources in the DLL, using a configuration file, or setting an environment variable. The function first tries to open the HesConfigFile and set the Hes_RHS and Hes_LHS variables from this. If there is no config file then the function tries to load a string resource from the DLL to set the LHS and RHS. If the string resources cannot be loaded then the LHS and RHS will be set by the values of DEF_LHS and DEF_RHS, these are defined in hesiod.h. Note that the string resources are by default set to these same values since the RC files include hesiod.h Finally if the user sets the environment variable HES_DOMAIN the RHS will be overridden by the value of the HES_DOMAIN value. Note that LoadString requires us to first find the module handle of the DLL. We have to use the internal module name as defined in the DEF file. If you change the library name within the DEF file you also need to change the appropriate string in hesiod.c */ int hes_init( void ) { register FILE *fp; register char *key; register char *cp; char buf[MAXDNAME+7]; HMODULE hModWSHelp; Hes_Errno = HES_ER_UNINIT; Hes_LHS[0] = '\0'; Hes_RHS[0] = '\0'; // Note: these must match the DEF file entries #if defined(_WIN64) hModWSHelp = GetModuleHandle( "WSHELP64" ); #else hModWSHelp = GetModuleHandle( "WSHELP32" ); #endif if(!LoadString( hModWSHelp, IDS_DEF_HES_CONFIG_FILE, HesConfigFile, sizeof(HesConfigFile) )){ strcpy( HesConfigFile, HESIOD_CONF); } if ((fp = fopen(HesConfigFile, "r")) == NULL) { /* use defaults compiled in */ /* no file or no access uses defaults */ /* but poorly formed file returns error */ if(!LoadString( hModWSHelp, IDS_DEF_HES_RHS, Hes_RHS, sizeof(Hes_RHS) )){ strcpy( Hes_RHS, DEF_RHS); } if(!LoadString( hModWSHelp, IDS_DEF_HES_LHS, Hes_LHS, sizeof(Hes_LHS) )){ strcpy( Hes_LHS, DEF_LHS); } } else { while(fgets((LPSTR) buf, MAXDNAME+7, fp) != NULL) { cp = (LPSTR) buf; if (*cp == '#' || *cp == '\n'){ continue; } while(*cp == ' ' || *cp == '\t'){ cp++; } key = cp; while(*cp != ' ' && *cp != '\t' && *cp != '='){ cp++; } *cp++ = '\0'; if (strcmp(key, "lhs") == 0){ strncpy(&Hes_LHS[0], cp, (strlen(cp)-1)); } else if (strcmp(key, "rhs") == 0){ strncpy(&Hes_RHS[0], cp, (strlen(cp)-1)); } else { continue; } while(*cp == ' ' || *cp == '\t' || *cp == '='){ cp++; } if (*cp != '.') { Hes_Errno = HES_ER_CONFIG; fclose(fp); return(Hes_Errno); } // len = strlen(cp); // *cpp = calloc((unsigned int) len, sizeof(char)); // (void) strncpy(*cpp, cp, len-1); } fclose(fp); } /* see if the RHS is overridden by environment variable */ if ((cp = getenv("HES_DOMAIN")) != NULL){ // Hes_RHS = strcpy(malloc(strlen(cp)+1),cp); strcpy(Hes_RHS,cp); } /* the LHS may be null, the RHS must not be null */ if (Hes_RHS == NULL) Hes_Errno = HES_ER_CONFIG; else Hes_Errno = HES_ER_OK; return(Hes_Errno); } /* hes_to_bind function use the LHS and RHS values and binds them with the parameters so that a well formed DNS query may be performed. \param[in] HesiodName The Hesiod name such as a username or service name \param[in] HesiodNameType The Hesiod name type such as pobox, passwd, or sloc \retval Returns NULL if there was an error. Otherwise the pointer to a string containing a valid query is returned. */ char * WINAPI hes_to_bind(LPSTR HesiodName, LPSTR HesiodNameType) { register char *cp, **cpp; char* bindname; LPVOID lpvData; char *RHS; cp = NULL; cpp = NULL; bindname = (LPSTR)(TlsGetValue(dwHesIndex)); if (bindname == NULL) { lpvData = LocalAlloc(LPTR, DNS_MAX_NAME_BUFFER_LENGTH); if (lpvData != NULL) { TlsSetValue(dwHesIndex, lpvData); bindname = (LPSTR)lpvData; } else return NULL; } if (Hes_Errno == HES_ER_UNINIT || Hes_Errno == HES_ER_CONFIG) (void) hes_init(); if (Hes_Errno == HES_ER_CONFIG) return(NULL); if (cp = index(HesiodName,'@')) { if (index(++cp,'.')) RHS = cp; else if (cpp = hes_resolve(cp, "rhs-extension")) RHS = *cpp; else { Hes_Errno = HES_ER_NOTFOUND; return(NULL); } (void) strcpy(bindname,HesiodName); (*index(bindname,'@')) = '\0'; } else { RHS = Hes_RHS; (void) strcpy(bindname, HesiodName); } (void) strcat(bindname, "."); (void) strcat(bindname, HesiodNameType); if (Hes_LHS) { if (Hes_LHS[0] != '.') (void) strcat(bindname,"."); (void) strcat(bindname, Hes_LHS); } if (RHS[0] != '.') (void) strcat(bindname,"."); (void) strcat(bindname, RHS); if(cpp != NULL ) hes_free(cpp); return(bindname); } /* This function calls hes_to_bind to form a valid hesiod query, then queries the dns database. defined in hesiod.c \param[in] HesiodName The Hesiod name such as a username or service name \param[in] HesiodNameType The Hesiod name type such as pobox, passwd, or sloc \retval returns a NULL terminated vector of strings (a la argv), one for each resource record containing Hesiod data, or NULL if there is any error. If there is an error call hes_error() to get further information. You will need to call hes_free to free the result */ char ** WINAPI hes_resolve(LPSTR HesiodName, LPSTR HesiodNameType) { register char *cp; LPSTR* retvec; DNS_STATUS status; PDNS_RECORD pDnsRecord; PDNS_RECORD pR; DNS_FREE_TYPE freetype ; int i = 0; freetype = DnsFreeRecordListDeep; cp = hes_to_bind(HesiodName, HesiodNameType); if (cp == NULL) return(NULL); errno = 0; status = DnsQuery_A(cp, //pointer to OwnerName DNS_TYPE_TEXT, //Type of the record to be queried DNS_QUERY_STANDARD, // Bypasses the resolver cache on the lookup. NULL, //contains DNS server IP address &pDnsRecord, //Resource record comprising the response NULL); //reserved for future use if (status) { errno = status; Hes_Errno = HES_ER_NOTFOUND; return NULL; } pR = pDnsRecord; while (pR) { if (pR->wType == DNS_TYPE_TEXT) i++; pR = pR->pNext; } i++; retvec = LocalAlloc(LPTR, i*sizeof(LPSTR)); pR = pDnsRecord; i = 0; while (pR) { if (pR->wType == DNS_TYPE_TEXT){ SIZE_T l = strlen(((pR->Data).Txt.pStringArray)[0]); retvec[i] = LocalAlloc(LPTR, l+1); strcpy(retvec[i], ((pR->Data).Txt.pStringArray)[0]); i++; } pR = pR->pNext; } retvec[i] = NULL; DnsRecordListFree(pDnsRecord, freetype); return retvec; } /* The function hes_error may be called to determine the source of the error. It does not take an argument. \retval return one of the HES_ER_* codes defined in hesiod.h. */ int WINAPI hes_error(void) { return(Hes_Errno); } /* The function hes_free should be called to free up memeory returned by hes_resolve \param[in] hesinfo a NULL terminiated array of strings returned by hes_resolve */ void WINAPI hes_free(LPSTR* info) { int i= 0; for (; info[i]; i++) { LocalFree(info[i]); } LocalFree(info); }