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

   1 /*
   2  * Copyright 1996-2013,2016 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  * Copyright 2013,2016 Mark Wooding <mdw@distorted.org.uk>
   8  *
   9  * This is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 3 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with userv-utils; if not, see http://www.gnu.org/licenses/.
  21  */
  22
  23 #include <assert.h>
  24 #include <ctype.h>
  25 #include <stdarg.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <errno.h>
  29
  30 #include <unistd.h>
  31
  32 #include "ucgi.h"
  33
  34 int debugmode= 0;
  35
  36 static void outerror(void) {
  37   perror("stdout");
  38   exit(debugmode ? 0 : -1);
  39 }
  40
  41 void syserror(const char *m) {
  42   if (printf("Content-Type: text/plain\n"
  43              "Status: 500\n\n"
  44              "ucgi: system call error:\n"
  45              "%s: %s\n",
  46              m,strerror(errno))==EOF || fflush(stdout)) outerror();
  47   exit(0);
  48 }
  49
  50 void error(const char *m, int st) {
  51   if (printf("Content-Type: text/plain\n"
  52              "Status: %d\n\n"
  53              "ucgi: error:\n"
  54              "%s\n",
  55              st, m)==EOF || fflush(stdout)) outerror();
  56   exit(0);
  57 }
  58
  59 void *xmalloc(size_t sz) {
  60   void *r;
  61
  62   r= malloc(sz);
  63   if (!r) syserror("malloc failed");
  64   return r;
  65 }
  66
  67 void *xrealloc(void *ptr, size_t sz) {
  68   void *r;
  69
  70   r= realloc(ptr,sz);
  71   if (!r) syserror("realloc failed");
  72   return r;
  73 }
  74
  75 void xsetenv(const char *en, const char *ev, int overwrite) {
  76   if (setenv(en,ev,overwrite)) syserror("setenv");
  77 }
  78
  79 const char **load_filters(unsigned flags, const char *first, ...) {
  80   va_list ap;
  81   const char *name, *p, *q, **v;
  82   char *pp;
  83   size_t l, n, sz;
  84   FILE *fp;
  85   char buf[MAX_ENVVAR_NAME];
  86
  87   D( if (debugmode) printf(";; load_filters...\n"); )
  88   va_start(ap, first);
  89   for (name= first; name; name= va_arg(ap, const char *)) {
  90     fp= fopen(name, "r"); if (fp) goto opened;
  91     D( if (debugmode)
  92          printf(";;   file `%s': %s\n", name, strerror(errno)); )
  93     if (errno != ENOENT) syserror("failed to open environment filters");
  94   }
  95   va_end(ap);
  96   if (flags & LOADF_MUST) syserror("failed to open environment filters");
  97   D( if (debugmode) printf(";;   using default filters\n"); )
  98   return 0;
  99
 100 opened:
 101   va_end(ap);
 102   D( if (debugmode) printf(";;   file `%s': OK\n", name); )
 103
 104   n= 0; sz= 128; v= xmalloc(sz * sizeof(*v));
 105   for (;;) {
 106     if (!fgets(buf, sizeof(buf), fp)) break;
 107     l= strlen(buf);
 108     if (buf[l - 1] == '\n') buf[--l]= 0;
 109     if (l + 1 == sizeof(buf))
 110       error("line too long in environment filter file", 500);
 111     p= buf; q= p + l;
 112     while (isspace((unsigned char)*p)) p++;
 113     while (q > p && isspace((unsigned char)q[-1])) q--;
 114     if (*p == '#' || p == q) continue;
 115     l= q - p;
 116     pp= xmalloc(l + 1);
 117     memcpy(pp, p, l);
 118     pp[l]= 0;
 119     v[n++]= pp;
 120     D( if (debugmode) printf(";;   filter: `%s'\n", pp); )
 121     if (n >= sz) {
 122       sz *= 2;
 123       v= xrealloc(v, sz * sizeof(*v));
 124     }
 125   }
 126   if (ferror(fp)) syserror("failed to read environment filters");
 127   fclose(fp);
 128   return v;
 129 }
 130
 131 static int envvar_match(unsigned flags, const char *en,
 132                         const char *const *patv,
 133                         const char *const *defaults,
 134                         const char **ev) {
 135   const char *const *patp;
 136   const char *q, *pat;
 137   int acceptp;
 138   int rc;
 139
 140   if (!patv) { patv= defaults; defaults= 0; }
 141   for (patp= patv; (pat= *patp); patp++) {
 142     q= en;
 143     acceptp= 1;
 144     if (*pat == '!' && (flags & FILTF_WILDCARD)) { acceptp= 0; pat++; }
 145     else if (*pat == '?') {
 146       if (strcmp(pat + 1, "DEFAULTS") == 0) {
 147         assert(defaults);
 148         rc= envvar_match(flags, en, defaults, 0, ev);
 149         if (rc) return rc;
 150       } else
 151         error("unknown pattern directive", 500);
 152       continue;
 153     }
 154
 155     for (;;) {
 156       if (!*pat) {
 157         if (*q != '=') {
 158           D( if (debugmode)
 159                printf(";;     mismatch `%s' (prefix)\n", *patp); )
 160           break;
 161         }
 162         D( if (debugmode) printf(";;     matched pattern `%s'\n", *patp); )
 163         goto match;
 164       } else if (*pat == '*' && (flags & FILTF_WILDCARD)) {
 165         q = strchr(q, '=');
 166         if (!q) {
 167           D( if (debugmode)
 168                printf(";;     mismatch `%s' (discard: no `=')\n", *patp); )
 169           return -1;
 170         }
 171         D( if (debugmode)
 172              printf(";;     wildcard match for `%s'\n", *patp); )
 173         goto match;
 174       } else {
 175         if (*pat++ != *q++) {
 176           D( if (debugmode) printf(";;     mismatch `%s'\n", *patp); )
 177           break;
 178         }
 179       }
 180     }
 181   }
 182   return 0;
 183
 184 match:
 185   if (!acceptp) return -1;
 186   *ev= q + 1;
 187   return +1;
 188 }
 189
 190 void filter_environment(unsigned flags, const char *prefix_in,
 191                         const char *const *patv,
 192                         const char *const *defaults,
 193                         void (*foundone)(const char *fulln,
 194                                          const char *en, const char *ev,
 195                                          void *p),
 196                         void *p) {
 197   char *const *ep;
 198   const char *en, *ev;
 199   char enbuf[MAX_ENVVAR_NAME];
 200   size_t n, pn = strlen(prefix_in);
 201
 202   D( if (debugmode) printf(";; filter_environment...\n"); )
 203   for (ep= environ; (en= *ep); ep++) {
 204     D( if (debugmode) printf(";;   consider env-var `%s'\n", en); )
 205     if (strncmp(en, prefix_in, pn) != 0 || !en[pn]) {
 206       D( if (debugmode) printf(";;     doesn't match prefix\n"); )
 207       continue;
 208     }
 209     if (envvar_match(flags, en + pn, patv, defaults, &ev) > 0) {
 210       n= strcspn(en, "=");
 211       if (n >= sizeof(enbuf))
 212         error("environment variable name too long", 500);
 213       memcpy(enbuf, en, n);
 214       enbuf[n]= 0;
 215       D( if (debugmode)
 216            printf(";;     full = `%s'; tail = `%s'; value = `%s'\n",
 217                   enbuf, enbuf + pn, ev); )
 218       foundone(enbuf, enbuf + pn, ev, p);
 219     }
 220   }
 221 }