src/src/lookups/lsearch.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2018 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8 #include "../exim.h"
   9 #include "lf_functions.h"
  10
  11 /* Codes for the different kinds of lsearch that are supported */
  12
  13 enum {
  14   LSEARCH_PLAIN,        /* Literal keys */
  15   LSEARCH_WILD,         /* Wild card keys, expanded */
  16   LSEARCH_NWILD,        /* Wild card keys, not expanded */
  17   LSEARCH_IP            /* IP addresses and networks */
  18 };
  19
  20
  21
  22 /*************************************************
  23 *              Open entry point                  *
  24 *************************************************/
  25
  26 /* See local README for interface description */
  27
  28 static void *
  29 lsearch_open(const uschar * filename, uschar ** errmsg)
  30 {
  31 FILE *f = Ufopen(filename, "rb");
  32 if (f == NULL)
  33   {
  34   int save_errno = errno;
  35   *errmsg = string_open_failed(errno, "%s for linear search", filename);
  36   errno = save_errno;
  37   return NULL;
  38   }
  39 return f;
  40 }
  41
  42
  43
  44 /*************************************************
  45 *             Check entry point                  *
  46 *************************************************/
  47
  48 static BOOL
  49 lsearch_check(void *handle, const uschar *filename, int modemask, uid_t *owners,
  50   gid_t *owngroups, uschar **errmsg)
  51 {
  52 return lf_check_file(fileno((FILE *)handle), filename, S_IFREG, modemask,
  53   owners, owngroups, "lsearch", errmsg) == 0;
  54 }
  55
  56
  57
  58 /*************************************************
  59 *  Internal function for the various lsearches   *
  60 *************************************************/
  61
  62 /* See local README for interface description, plus:
  63
  64 Extra argument:
  65
  66   type     one of the values LSEARCH_PLAIN, LSEARCH_WILD, LSEARCH_NWILD, or
  67            LSEARCH_IP
  68
  69 There is some messy logic in here to cope with very long data lines that do not
  70 fit into the fixed sized buffer. Most of the time this will never be exercised,
  71 but people do occasionally do weird things. */
  72
  73 static int
  74 internal_lsearch_find(void * handle, const uschar * filename,
  75   const uschar * keystring, int length, uschar ** result, uschar ** errmsg,
  76  int type)
  77 {
  78 FILE *f = (FILE *)handle;
  79 BOOL last_was_eol = TRUE;
  80 BOOL this_is_eol = TRUE;
  81 int old_pool = store_pool;
  82 rmark reset_point = NULL;
  83 uschar buffer[4096];
  84
  85 /* Wildcard searches may use up some store, because of expansions. We don't
  86 want them to fill up our search store. What we do is set the pool to the main
  87 pool and get a point to reset to later. Wildcard searches could also issue
  88 lookups, but internal_search_find will take care of that, and the cache will be
  89 safely stored in the search pool again. */
  90
  91 if(type == LSEARCH_WILD || type == LSEARCH_NWILD)
  92   {
  93   store_pool = POOL_MAIN;
  94   reset_point = store_mark();
  95   }
  96
  97 filename = filename;  /* Keep picky compilers happy */
  98 errmsg = errmsg;
  99
 100 rewind(f);
 101 for (last_was_eol = TRUE;
 102      Ufgets(buffer, sizeof(buffer), f) != NULL;
 103      last_was_eol = this_is_eol)
 104   {
 105   int p = Ustrlen(buffer);
 106   int linekeylength;
 107   BOOL this_is_comment;
 108   gstring * yield;
 109   uschar *s = buffer;
 110
 111   /* Check whether this the final segment of a line. If it follows an
 112   incomplete part-line, skip it. */
 113
 114   this_is_eol = p > 0 && buffer[p-1] == '\n';
 115   if (!last_was_eol) continue;
 116
 117   /* We now have the start of a physical line. If this is a final line segment,
 118   remove trailing white space. */
 119
 120   if (this_is_eol)
 121     {
 122     while (p > 0 && isspace((uschar)buffer[p-1])) p--;
 123     buffer[p] = 0;
 124     }
 125
 126   /* If the buffer is empty it might be (a) a complete empty line, or (b) the
 127   start of a line that begins with so much white space that it doesn't all fit
 128   in the buffer. In both cases we want to skip the entire physical line.
 129
 130   If the buffer begins with # it is a comment line; if it begins with white
 131   space it is a logical continuation; again, we want to skip the entire
 132   physical line. */
 133
 134   if (buffer[0] == 0 || buffer[0] == '#' || isspace(buffer[0])) continue;
 135
 136   /* We assume that they key will fit in the buffer. If the key starts with ",
 137   read it as a quoted string. We don't use string_dequote() because that uses
 138   new store for the result, and we may be doing this many times in a long file.
 139   We know that the dequoted string must be shorter than the original, because
 140   we are removing the quotes, and also any escape sequences always turn two or
 141   more characters into one character. Therefore, we can store the new string in
 142   the same buffer. */
 143
 144   if (*s == '\"')
 145     {
 146     uschar *t = s++;
 147     while (*s != 0 && *s != '\"')
 148       {
 149       if (*s == '\\') *t++ = string_interpret_escape(CUSS &s);
 150         else *t++ = *s;
 151       s++;
 152       }
 153     if (*s != 0) s++;               /* Past terminating " */
 154     linekeylength = t - buffer;
 155     }
 156
 157   /* Otherwise it is terminated by a colon or white space */
 158
 159   else
 160     {
 161     while (*s != 0 && *s != ':' && !isspace(*s)) s++;
 162     linekeylength = s - buffer;
 163     }
 164
 165   /* The matching test depends on which kind of lsearch we are doing */
 166
 167   switch(type)
 168     {
 169     /* A plain lsearch treats each key as a literal */
 170
 171     case LSEARCH_PLAIN:
 172     if (linekeylength != length || strncmpic(buffer, keystring, length) != 0)
 173       continue;
 174     break;      /* Key matched */
 175
 176     /* A wild lsearch treats each key as a possible wildcarded string; no
 177     expansion is done for nwildlsearch. */
 178
 179     case LSEARCH_WILD:
 180     case LSEARCH_NWILD:
 181       {
 182       int rc;
 183       int save = buffer[linekeylength];
 184       const uschar *list = buffer;
 185       buffer[linekeylength] = 0;
 186       rc = match_isinlist(keystring,
 187         &list,
 188         UCHAR_MAX+1,              /* Single-item list */
 189         NULL,                     /* No anchor */
 190         NULL,                     /* No caching */
 191         MCL_STRING + ((type == LSEARCH_WILD)? 0:MCL_NOEXPAND),
 192         TRUE,                     /* Caseless */
 193         NULL);
 194       buffer[linekeylength] = save;
 195       if (rc == FAIL) continue;
 196       if (rc == DEFER) return DEFER;
 197       }
 198
 199     /* The key has matched. If the search involved a regular expression, it
 200     might have caused numerical variables to be set. However, their values will
 201     be in the wrong storage pool for external use. Copying them to the standard
 202     pool is not feasible because of the caching of lookup results - a repeated
 203     lookup will not match the regular expression again. Therefore, we flatten
 204     all numeric variables at this point. */
 205
 206     expand_nmax = -1;
 207     break;
 208
 209     /* Compare an ip address against a list of network/ip addresses. We have to
 210     allow for the "*" case specially. */
 211
 212     case LSEARCH_IP:
 213     if (linekeylength == 1 && buffer[0] == '*')
 214       {
 215       if (length != 1 || keystring[0] != '*') continue;
 216       }
 217     else if (length == 1 && keystring[0] == '*') continue;
 218     else
 219       {
 220       int maskoffset;
 221       int save = buffer[linekeylength];
 222       buffer[linekeylength] = 0;
 223       if (string_is_ip_address(buffer, &maskoffset) == 0 ||
 224           !host_is_in_net(keystring, buffer, maskoffset)) continue;
 225       buffer[linekeylength] = save;
 226       }
 227     break;      /* Key matched */
 228     }
 229
 230   /* The key has matched. Skip spaces after the key, and allow an optional
 231   colon after the spaces. This is an odd specification, but it's for
 232   compatibility. */
 233
 234   while (isspace((uschar)*s)) s++;
 235   if (*s == ':')
 236     {
 237     s++;
 238     while (isspace((uschar)*s)) s++;
 239     }
 240
 241   /* Reset dynamic store, if we need to, and revert to the search pool */
 242
 243   if (reset_point)
 244     {
 245     reset_point = store_reset(reset_point);
 246     store_pool = old_pool;
 247     }
 248
 249   /* Now we want to build the result string to contain the data. There can be
 250   two kinds of continuation: (a) the physical line may not all have fitted into
 251   the buffer, and (b) there may be logical continuation lines, for which we
 252   must convert all leading white space into a single blank.
 253
 254   Initialize, and copy the first segment of data. */
 255
 256   this_is_comment = FALSE;
 257   yield = string_get(100);
 258   if (*s != 0)
 259     yield = string_cat(yield, s);
 260
 261   /* Now handle continuations */
 262
 263   for (last_was_eol = this_is_eol;
 264        Ufgets(buffer, sizeof(buffer), f) != NULL;
 265        last_was_eol = this_is_eol)
 266     {
 267     s = buffer;
 268     p = Ustrlen(buffer);
 269     this_is_eol = p > 0 && buffer[p-1] == '\n';
 270
 271     /* Remove trailing white space from a physical line end */
 272
 273     if (this_is_eol)
 274       {
 275       while (p > 0 && isspace((uschar)buffer[p-1])) p--;
 276       buffer[p] = 0;
 277       }
 278
 279     /* If this is not a physical line continuation, skip it entirely if it's
 280     empty or starts with #. Otherwise, break the loop if it doesn't start with
 281     white space. Otherwise, replace leading white space with a single blank. */
 282
 283     if (last_was_eol)
 284       {
 285       this_is_comment = (this_is_comment || (buffer[0] == 0 || buffer[0] == '#'));
 286       if (this_is_comment) continue;
 287       if (!isspace((uschar)buffer[0])) break;
 288       while (isspace((uschar)*s)) s++;
 289       *(--s) = ' ';
 290       }
 291     if (this_is_comment) continue;
 292
 293     /* Join a physical or logical line continuation onto the result string. */
 294
 295     yield = string_cat(yield, s);
 296     }
 297
 298   gstring_release_unused(yield);
 299   *result = string_from_gstring(yield);
 300   return OK;
 301   }
 302
 303 /* Reset dynamic store, if we need to */
 304
 305 if (reset_point)
 306   {
 307   store_reset(reset_point);
 308   store_pool = old_pool;
 309   }
 310
 311 return FAIL;
 312 }
 313
 314
 315 /*************************************************
 316 *         Find entry point for lsearch           *
 317 *************************************************/
 318
 319 /* See local README for interface description */
 320
 321 static int
 322 lsearch_find(void * handle, const uschar * filename, const uschar * keystring,
 323   int length, uschar ** result, uschar ** errmsg, uint * do_cache)
 324 {
 325 do_cache = do_cache;  /* Keep picky compilers happy */
 326 return internal_lsearch_find(handle, filename, keystring, length, result,
 327   errmsg, LSEARCH_PLAIN);
 328 }
 329
 330
 331
 332 /*************************************************
 333 *      Find entry point for wildlsearch          *
 334 *************************************************/
 335
 336 /* See local README for interface description */
 337
 338 static int
 339 wildlsearch_find(void * handle, const uschar * filename, const uschar * keystring,
 340   int length, uschar ** result, uschar ** errmsg, uint * do_cache)
 341 {
 342 do_cache = do_cache;  /* Keep picky compilers happy */
 343 return internal_lsearch_find(handle, filename, keystring, length, result,
 344   errmsg, LSEARCH_WILD);
 345 }
 346
 347
 348
 349 /*************************************************
 350 *      Find entry point for nwildlsearch         *
 351 *************************************************/
 352
 353 /* See local README for interface description */
 354
 355 static int
 356 nwildlsearch_find(void * handle, const uschar * filename, const uschar * keystring,
 357   int length, uschar ** result, uschar ** errmsg, uint * do_cache)
 358 {
 359 do_cache = do_cache;  /* Keep picky compilers happy */
 360 return internal_lsearch_find(handle, filename, keystring, length, result,
 361   errmsg, LSEARCH_NWILD);
 362 }
 363
 364
 365
 366
 367 /*************************************************
 368 *      Find entry point for iplsearch            *
 369 *************************************************/
 370
 371 /* See local README for interface description */
 372
 373 static int
 374 iplsearch_find(void * handle, uschar const * filename, const uschar * keystring,
 375   int length, uschar ** result, uschar ** errmsg, uint * do_cache)
 376 {
 377 do_cache = do_cache;  /* Keep picky compilers happy */
 378
 379 if ((length == 1 && keystring[0] == '*') ||
 380     string_is_ip_address(keystring, NULL) != 0)
 381   return internal_lsearch_find(handle, filename, keystring, length, result,
 382     errmsg, LSEARCH_IP);
 383
 384 *errmsg = string_sprintf("\"%s\" is not a valid iplsearch key (an IP "
 385 "address, with optional CIDR mask, is wanted): "
 386 "in a host list, use net-iplsearch as the search type", keystring);
 387 return DEFER;
 388 }
 389
 390
 391
 392
 393 /*************************************************
 394 *              Close entry point                 *
 395 *************************************************/
 396
 397 /* See local README for interface description */
 398
 399 static void
 400 lsearch_close(void *handle)
 401 {
 402 (void)fclose((FILE *)handle);
 403 }
 404
 405
 406
 407 /*************************************************
 408 *         Version reporting entry point          *
 409 *************************************************/
 410
 411 /* See local README for interface description. */
 412
 413 #include "../version.h"
 414
 415 void
 416 lsearch_version_report(FILE *f)
 417 {
 418 #ifdef DYNLOOKUP
 419 fprintf(f, "Library version: lsearch: Exim version %s\n", EXIM_VERSION_STR);
 420 #endif
 421 }
 422
 423
 424 static lookup_info iplsearch_lookup_info = {
 425   US"iplsearch",                 /* lookup name */
 426   lookup_absfile,                /* uses absolute file name */
 427   lsearch_open,                  /* open function */
 428   lsearch_check,                 /* check function */
 429   iplsearch_find,                /* find function */
 430   lsearch_close,                 /* close function */
 431   NULL,                          /* no tidy function */
 432   NULL,                          /* no quoting function */
 433   NULL                           /* no version reporting (redundant) */
 434 };
 435
 436 static lookup_info lsearch_lookup_info = {
 437   US"lsearch",                   /* lookup name */
 438   lookup_absfile,                /* uses absolute file name */
 439   lsearch_open,                  /* open function */
 440   lsearch_check,                 /* check function */
 441   lsearch_find,                  /* find function */
 442   lsearch_close,                 /* close function */
 443   NULL,                          /* no tidy function */
 444   NULL,                          /* no quoting function */
 445   lsearch_version_report         /* version reporting */
 446 };
 447
 448 static lookup_info nwildlsearch_lookup_info = {
 449   US"nwildlsearch",              /* lookup name */
 450   lookup_absfile,                /* uses absolute file name */
 451   lsearch_open,                  /* open function */
 452   lsearch_check,                 /* check function */
 453   nwildlsearch_find,             /* find function */
 454   lsearch_close,                 /* close function */
 455   NULL,                          /* no tidy function */
 456   NULL,                          /* no quoting function */
 457   NULL                           /* no version reporting (redundant) */
 458 };
 459
 460 static lookup_info wildlsearch_lookup_info = {
 461   US"wildlsearch",               /* lookup name */
 462   lookup_absfile,                /* uses absolute file name */
 463   lsearch_open,                  /* open function */
 464   lsearch_check,                 /* check function */
 465   wildlsearch_find,              /* find function */
 466   lsearch_close,                 /* close function */
 467   NULL,                          /* no tidy function */
 468   NULL,                          /* no quoting function */
 469   NULL                           /* no version reporting (redundant) */
 470 };
 471
 472 #ifdef DYNLOOKUP
 473 #define lsearch_lookup_module_info _lookup_module_info
 474 #endif
 475
 476 static lookup_info *_lookup_list[] = { &iplsearch_lookup_info,
 477                                        &lsearch_lookup_info,
 478                                        &nwildlsearch_lookup_info,
 479                                        &wildlsearch_lookup_info };
 480 lookup_module_info lsearch_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 4 };
 481
 482 /* End of lookups/lsearch.c */