/* ** mod_define.c - Apache module for configuration defines ($xxx) ** ** Copyright (c) 1998-2000 Ralf S. Engelschall ** Copyright (c) 1998-2000 Christian Reiber ** ** Permission to use, copy, modify, and distribute this software for ** any purpose with or without fee is hereby granted, provided that ** the above copyright notice and this permission notice appear in all ** copies. ** ** THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED ** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF ** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. ** IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR ** CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF ** USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ** ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, ** OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ** OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF ** SUCH DAMAGE. */ /* * HISTORY * * v1.0: Originally written in December 1998 by * Ralf S. Engelschall and * Christian Reiber * * v1.1: Completely Overhauled in August 1999 by * Ralf S. Engelschall */ #include "ap_config.h" #include "ap_ctype.h" #include "httpd.h" #include "http_config.h" #include "http_conf_globals.h" #include "http_core.h" #include "http_log.h" #ifndef EAPI #error "This module requires the Extended API (EAPI) facilities." #endif /* * The global table of defines */ static table *tDefines = NULL; /* global table of defines */ static int bOnceSeenADefine = FALSE; /* optimization flag */ /* * Forward declaration */ static int DefineIndex (pool *, char *, int *, int *, char **); static char *DefineFetch (pool *, char *); static char *DefineExpand (pool *, char *, int, char *); static void DefineInit (pool *); static void DefineCleanup (void *); static char *DefineRewriteHook(cmd_parms *, void *, const char *); /* * Character classes for scanner function */ typedef enum { CC_ESCAPE, CC_DOLLAR, CC_BRACEOPEN, CC_BRACECLOSE, CC_IDCHAR1, CC_IDCHAR, CC_OTHER, CC_EOS } CharClass; /* * Scanner states for scanner function */ typedef enum { SS_NONE, SS_SKIP, SS_DOLLAR, SS_TOKEN_BRACED, SS_TOKEN_UNBRACED, SS_ERROR, SS_FOUND } ScanState; /* * Default meta characters */ #define DEFAULT_MC_ESCAPE "\\" #define DEFAULT_MC_DOLLAR "$" #define DEFAULT_MC_BRACEOPEN "{" #define DEFAULT_MC_BRACECLOSE "}" /* * Scanner for variable constructs $xxx and ${xxx} */ static int DefineIndex(pool *p, char *cpLine, int *pos, int *len, char **cpVar) { int rc; char *cp; char *cp2; CharClass cc; char cEscape; char cDefine; char cBraceOpen; char cBraceClose; char *cpError; ScanState s; cEscape = DEFAULT_MC_ESCAPE[0]; if ((cp = DefineFetch(p, "mod_define::escape")) != NULL) cEscape = cp[0]; cDefine = DEFAULT_MC_DOLLAR[0]; if ((cp = DefineFetch(p, "mod_define::dollar")) != NULL) cDefine = cp[0]; cBraceOpen = DEFAULT_MC_BRACEOPEN[0]; if ((cp = DefineFetch(p, "mod_define::braceopen")) != NULL) cBraceOpen = cp[0]; cBraceClose = DEFAULT_MC_BRACECLOSE[0]; if ((cp = DefineFetch(p, "mod_define::braceclose")) != NULL) cBraceClose = cp[0]; rc = 0; *len = 0; cc = CC_OTHER; s = SS_NONE; for (cp = cpLine+(*pos); cc != CC_EOS; cp++) { if (*cp == cEscape) cc = CC_ESCAPE; else if (*cp == cDefine) cc = CC_DOLLAR; else if (*cp == cBraceOpen) cc = CC_BRACEOPEN; else if (*cp == cBraceClose) cc = CC_BRACECLOSE; else if (ap_isalpha(*cp)) cc = CC_IDCHAR1; else if (ap_isdigit(*cp) || *cp == '_' || *cp == ':') cc = CC_IDCHAR; else if (*cp == '\0') cc = CC_EOS; else cc = CC_OTHER; switch (s) { case SS_NONE: switch (cc) { case CC_ESCAPE: s = SS_SKIP; break; case CC_DOLLAR: s = SS_DOLLAR; break; default: break; } break; case SS_SKIP: s = SS_NONE; continue; break; case SS_DOLLAR: switch (cc) { case CC_BRACEOPEN: s = SS_TOKEN_BRACED; *pos = cp-cpLine-1; (*len) = 2; *cpVar = cp+1; break; case CC_IDCHAR1: s = SS_TOKEN_UNBRACED; *pos = cp-cpLine-1; (*len) = 2; *cpVar = cp; break; case CC_ESCAPE: s = SS_SKIP; break; default: s = SS_NONE; break; } break; case SS_TOKEN_BRACED: switch (cc) { case CC_IDCHAR1: case CC_IDCHAR: (*len)++; break; case CC_BRACECLOSE: (*len)++; cp2 = ap_palloc(p, cp-*cpVar+1); ap_cpystrn(cp2, *cpVar, cp-*cpVar+1); *cpVar = cp2; s = SS_FOUND; break; default: cpError = ap_psprintf(p, "Illegal character '%c' in identifier", *cp); s = SS_ERROR; break; } break; case SS_TOKEN_UNBRACED: switch (cc) { case CC_IDCHAR1: case CC_IDCHAR: (*len)++; break; default: cp2 = ap_palloc(p, cp-*cpVar+1); ap_cpystrn(cp2, *cpVar, cp-*cpVar+1); *cpVar = cp2; s = SS_FOUND; break; } break; case SS_FOUND: case SS_ERROR: break; } if (s == SS_ERROR) { fprintf(stderr, "Error\n"); break; } else if (s == SS_FOUND) { rc = 1; break; } } return rc; } /* * Determine the value of a variable */ static char *DefineFetch(pool *p, char *cpVar) { char *cpVal; /* first try out table */ if ((cpVal = (char *)ap_table_get(tDefines, (char *)cpVar)) != NULL) return cpVal; /* second try the environment */ if ((cpVal = getenv(cpVar)) != NULL) return cpVal; return NULL; } /* * Expand a variable */ static char *DefineExpand(pool *p, char *cpToken, int tok_len, char *cpVal) { char *cp; int val_len, rest_len; val_len = strlen(cpVal); rest_len = strlen(cpToken+tok_len); if (val_len < tok_len) memcpy(cpToken+val_len, cpToken+tok_len, rest_len+1); else if (val_len > tok_len) for (cp = cpToken+strlen(cpToken); cp > cpToken+tok_len-1; cp--) *(cp+(val_len-tok_len)) = *cp; memcpy(cpToken, cpVal, val_len); return NULL; } /* * The EAPI hook which is called after Apache has read a * configuration line and before it's actually processed */ static char *DefineRewriteHook(cmd_parms *cmd, void *config, const char *line) { pool *p; char *cpBuf; char *cpLine; int pos; int len; char *cpError; char *cpVar; char *cpVal; server_rec *s; /* runtime optimization */ if (!bOnceSeenADefine) return NULL; p = cmd->pool; s = cmd->server; /* * Search for: * ....\$[a-zA-Z][:_a-zA-Z0-9]*.... * ....\${[a-zA-Z][:_a-zA-Z0-9]*}.... */ cpBuf = NULL; cpLine = (char *)line; pos = 0; while (DefineIndex(p, cpLine, &pos, &len, &cpVar)) { #ifdef DEFINE_DEBUG { char prefix[1024]; char marker[1024]; int i; for (i = 0; i < pos; i++) prefix[i] = ' '; prefix[i] = '\0'; for (i = 0; i < len; i++) marker[i] = '^'; marker[i] = '\0'; fprintf(stderr, "Found variable `%s' (pos: %d, len: %d)\n" " %s\n" " %s%s\n", cpVar, pos, len, cpLine, prefix, marker); } #endif if (cpBuf == NULL) { cpBuf = ap_palloc(p, MAX_STRING_LEN); ap_cpystrn(cpBuf, line, MAX_STRING_LEN); cpLine = cpBuf; } if ((cpVal = DefineFetch(p, cpVar)) == NULL) { ap_log_error(APLOG_MARK, APLOG_ERR, s, "mod_define: Variable '%s' not defined: file %s, line %d", cpVar, cmd->config_file->name, cmd->config_file->line_number); cpBuf = NULL; break; } if ((cpError = DefineExpand(p, cpLine+pos, len, cpVal)) != NULL) { ap_log_error(APLOG_MARK, APLOG_ERR, s, "mod_define: %s: file %s, line %d", cpError, cmd->config_file->name, cmd->config_file->line_number); cpBuf = NULL; break; } } return cpBuf; } /* * Implementation of the `Define' configuration directive */ static const char *cmd_define(cmd_parms *cmd, void *config, char *cpVar, char *cpVal) { if (tDefines == NULL) DefineInit(cmd->pool); ap_table_set(tDefines, cpVar, cpVal); bOnceSeenADefine = TRUE; return NULL; } /* * Module Initialization */ static void DefineInit(pool *p) { tDefines = ap_make_table(p, 10); /* predefine delimiters */ ap_table_set(tDefines, "mod_define::escape", DEFAULT_MC_ESCAPE); ap_table_set(tDefines, "mod_define::dollar", DEFAULT_MC_DOLLAR); ap_table_set(tDefines, "mod_define::open", DEFAULT_MC_BRACEOPEN); ap_table_set(tDefines, "mod_define::close", DEFAULT_MC_BRACECLOSE); ap_register_cleanup(p, NULL, DefineCleanup, ap_null_cleanup); return; } /* * Module Cleanup */ static void DefineCleanup(void *data) { /* reset private variables when config pool is cleared */ tDefines = NULL; bOnceSeenADefine = FALSE; return; } /* * Module Directive lists */ static const command_rec DefineDirectives[] = { { "Define", cmd_define, NULL, RSRC_CONF|ACCESS_CONF, TAKE2, "Define a configuration variable" }, { NULL } }; /* * Module API dispatch list */ module MODULE_VAR_EXPORT define_module = { STANDARD_MODULE_STUFF, NULL, /* module initializer */ NULL, /* create per-dir config structures */ NULL, /* merge per-dir config structures */ NULL, /* create per-server config structures */ NULL, /* merge per-server config structures */ DefineDirectives, /* table of config file commands */ NULL, /* [#8] MIME-typed-dispatched handlers */ NULL, /* [#1] URI to filename translation */ NULL, /* [#4] validate user id from request */ NULL, /* [#5] check if the user is ok _here_ */ NULL, /* [#2] check access by host address */ NULL, /* [#6] determine MIME type */ NULL, /* [#7] pre-run fixups */ NULL, /* [#9] log a transaction */ NULL, /* [#3] header parser */ NULL, /* child_init */ NULL, /* child_exit */ NULL, /* [#0] post read-request */ NULL, /* EAPI: add_module */ NULL, /* EAPI: del_module */ DefineRewriteHook, /* EAPI: rewrite_command */ NULL /* EAPI: new_connection */ };