mdw@git.distorted.org.uk Git - userv-utils/blob - www-cgi/ucgicommon.c

   1 /*
   2  * Copyright 1996-2013 Ian Jackson <ijackson@chiark.greenend.org.uk>
   3  * Copyright 1998 David Damerell <damerell@chiark.greenend.org.uk>
   4  * Copyright 1999,2003
   5  *    Chancellor Masters and Scholars of the University of Cambridge
   6  * Copyright 2010 Tony Finch <fanf@dotat.at>
   7  *
   8  * This is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with userv-utils; if not, see http://www.gnu.org/licenses/.
  20  */
  21
  22 #include <assert.h>
  23 #include <ctype.h>
  24 #include <stdarg.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <errno.h>
  28
  29 #include <unistd.h>
  30
  31 #include "ucgi.h"
  32
  33 int debugmode= 0;
  34
  35 static void outerror(void) {
  36   perror("stdout");
  37   exit(debugmode ? 0 : -1);
  38 }
  39
  40 void syserror(const char *m) {
  41   if (printf("Content-Type: text/plain\n"
  42              "Status: 500\n\n"
  43              "ucgi: system call error:\n"
  44              "%s: %s\n",
  45              m,strerror(errno))==EOF || fflush(stdout)) outerror();
  46   exit(0);
  47 }
  48
  49 void error(const char *m, int st) {
  50   if (printf("Content-Type: text/plain\n"
  51              "Status: %d\n\n"
  52              "ucgi: error:\n"
  53              "%s\n",
  54              st, m)==EOF || fflush(stdout)) outerror();
  55   exit(0);
  56 }
  57
  58 void *xmalloc(size_t sz) {
  59   void *r;
  60
  61   r= malloc(sz);
  62   if (!r) syserror("malloc failed");
  63   return r;
  64 }
  65
  66 void *xrealloc(void *ptr, size_t sz) {
  67   void *r;
  68
  69   r= realloc(ptr,sz);
  70   if (!r) syserror("realloc failed");
  71   return r;
  72 }
  73
  74 void xsetenv(const char *en, const char *ev, int overwrite) {
  75   if (setenv(en,ev,overwrite)) syserror("setenv");
  76 }
  77
  78 const char **load_filters(unsigned flags, const char *first, ...) {
  79   va_list ap;
  80   const char *name, *p, *q, **v;
  81   char *pp;
  82   size_t l, n, sz;
  83   FILE *fp;
  84   char buf[MAX_ENVVAR_NAME];
  85
  86   D( if (debugmode) printf(";; load_filters...\n"); )
  87   va_start(ap, first);
  88   for (name= first; name; name= va_arg(ap, const char *)) {
  89     fp= fopen(name, "r"); if (fp) goto opened;
  90     D( if (debugmode)
  91          printf(";;   file `%s': %s\n", name, strerror(errno)); )
  92     if (errno != ENOENT) syserror("failed to open environment filters");
  93   }
  94   va_end(ap);
  95   if (flags & LOADF_MUST) syserror("failed to open environment filters");
  96   D( if (debugmode) printf(";;   using default filters\n"); )
  97   return 0;
  98
  99 opened:
 100   va_end(ap);
 101   D( if (debugmode) printf(";;   file `%s': OK\n", name); )
 102
 103   n= 0; sz= 128; v= xmalloc(sz * sizeof(*v));
 104   for (;;) {
 105     if (!fgets(buf, sizeof(buf), fp)) break;
 106     l= strlen(buf);
 107     if (buf[l - 1] == '\n') buf[--l]= 0;
 108     if (l + 1 == sizeof(buf))
 109       error("line too long in environment filter file", 500);
 110     p= buf; q= p + l;
 111     while (isspace((unsigned char)*p)) p++;
 112     while (q > p && isspace((unsigned char)q[-1])) q--;
 113     if (*p == '#' || p == q) continue;
 114     l= q - p;
 115     pp= xmalloc(l + 1);
 116     memcpy(pp, p, l);
 117     pp[l]= 0;
 118     v[n++]= pp;
 119     D( if (debugmode) printf(";;   filter: `%s'\n", pp); )
 120     if (n >= sz) {
 121       sz *= 2;
 122       v= xrealloc(v, sz * sizeof(*v));
 123     }
 124   }
 125   if (ferror(fp)) syserror("failed to read environment filters");
 126   fclose(fp);
 127   return v;
 128 }
 129
 130 static int envvar_match(unsigned flags, const char *en,
 131                         const char *const *patv,
 132                         const char *const *defaults,
 133                         const char **ev) {
 134   const char *const *patp;
 135   const char *q, *pat;
 136   int acceptp;
 137   int rc;
 138
 139   if (!patv) { patv= defaults; defaults= 0; }
 140   for (patp= patv; (pat= *patp); patp++) {
 141     q= en;
 142     acceptp= 1;
 143     if (*pat == '!' && (flags & FILTF_WILDCARD)) { acceptp= 0; pat++; }
 144     else if (*pat == '?') {
 145       if (strcmp(pat + 1, "DEFAULTS") == 0) {
 146         assert(defaults);
 147         rc= envvar_match(flags, en, defaults, 0, ev);
 148         if (rc) return rc;
 149       } else
 150         error("unknown pattern directive", 500);
 151       continue;
 152     }
 153
 154     for (;;) {
 155       if (!*pat) {
 156         if (*q != '=') {
 157           D( if (debugmode)
 158                printf(";;     mismatch `%s' (prefix)\n", *patp); )
 159           break;
 160         }
 161         D( if (debugmode) printf(";;     matched pattern `%s'\n", *patp); )
 162         goto match;
 163       } else if (*pat == '*' && (flags & FILTF_WILDCARD)) {
 164         q = strchr(q, '=');
 165         if (!q) {
 166           D( if (debugmode)
 167                printf(";;     mismatch `%s' (discard: no `=')\n", *patp); )
 168           return -1;
 169         }
 170         D( if (debugmode)
 171              printf(";;     wildcard match for `%s'\n", *patp); )
 172         goto match;
 173       } else {
 174         if (*pat++ != *q++) {
 175           D( if (debugmode) printf(";;     mismatch `%s'\n", *patp); )
 176           break;
 177         }
 178       }
 179     }
 180   }
 181   return 0;
 182
 183 match:
 184   if (!acceptp) return -1;
 185   *ev= q + 1;
 186   return +1;
 187 }
 188
 189 void filter_environment(unsigned flags, const char *prefix_in,
 190                         const char *const *patv,
 191                         const char *const *defaults,
 192                         void (*foundone)(const char *fulln,
 193                                          const char *en, const char *ev,
 194                                          void *p),
 195                         void *p) {
 196   char *const *ep;
 197   const char *en, *ev;
 198   char enbuf[MAX_ENVVAR_NAME];
 199   size_t n, pn = strlen(prefix_in);
 200
 201   D( if (debugmode) printf(";; filter_environment...\n"); )
 202   for (ep= environ; (en= *ep); ep++) {
 203     D( if (debugmode) printf(";;   consider env-var `%s'\n", en); )
 204     if (strncmp(en, prefix_in, pn) != 0 || !en[pn]) {
 205       D( if (debugmode) printf(";;     doesn't match prefix\n"); )
 206       continue;
 207     }
 208     if (envvar_match(flags, en + pn, patv, defaults, &ev) > 0) {
 209       n= strcspn(en, "=");
 210       if (n >= sizeof(enbuf))
 211         error("environment variable name too long", 500);
 212       memcpy(enbuf, en, n);
 213       enbuf[n]= 0;
 214       D( if (debugmode)
 215            printf(";;     full = `%s'; tail = `%s'; value = `%s'\n",
 216                   enbuf, enbuf + pn, ev); )
 217       foundone(enbuf, enbuf + pn, ev, p);
 218     }
 219   }
 220 }