src/src/lookups/dsearch.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2015 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8 /* The idea for this code came from Matthew Byng-Maddick, but his original has
   9 been heavily reworked a lot for Exim 4 (and it now uses stat() (more precisely:
  10 lstat()) rather than a directory scan). */
  11
  12
  13 #include "../exim.h"
  14 #include "lf_functions.h"
  15
  16
  17
  18 /*************************************************
  19 *              Open entry point                  *
  20 *************************************************/
  21
  22 /* See local README for interface description. We open the directory to test
  23 whether it exists and whether it is searchable. However, we don't need to keep
  24 it open, because the "search" can be done by a call to lstat() rather than
  25 actually scanning through the list of files. */
  26
  27 static void *
  28 dsearch_open(uschar *dirname, uschar **errmsg)
  29 {
  30 DIR *dp = opendir(CS dirname);
  31 if (!dp)
  32   {
  33   int save_errno = errno;
  34   *errmsg = string_open_failed(errno, "%s for directory search", dirname);
  35   errno = save_errno;
  36   return NULL;
  37   }
  38 closedir(dp);
  39 return (void *)(-1);
  40 }
  41
  42
  43 /*************************************************
  44 *             Check entry point                  *
  45 *************************************************/
  46
  47 /* The handle will always be (void *)(-1), but don't try casting it to an
  48 integer as this gives warnings on 64-bit systems. */
  49
  50 static BOOL
  51 dsearch_check(void *handle, uschar *filename, int modemask, uid_t *owners,
  52   gid_t *owngroups, uschar **errmsg)
  53 {
  54 handle = handle;
  55 return lf_check_file(-1, filename, S_IFDIR, modemask, owners, owngroups,
  56   "dsearch", errmsg) == 0;
  57 }
  58
  59
  60 /*************************************************
  61 *              Find entry point                  *
  62 *************************************************/
  63
  64 /* See local README for interface description. We use lstat() instead of
  65 scanning the directory, as it is hopefully faster to let the OS do the scanning
  66 for us. */
  67
  68 static int
  69 dsearch_find(void *handle, uschar *dirname, const uschar *keystring, int length,
  70   uschar **result, uschar **errmsg, uint *do_cache)
  71 {
  72 struct stat statbuf;
  73 int save_errno;
  74 uschar * filename;
  75
  76 handle = handle;  /* Keep picky compilers happy */
  77 length = length;
  78 do_cache = do_cache;
  79
  80 if (Ustrchr(keystring, '/') != 0)
  81   {
  82   *errmsg = string_sprintf("key for dsearch lookup contains a slash: %s",
  83     keystring);
  84   return DEFER;
  85   }
  86
  87 filename = string_sprintf("%s/%s", dirname, keystring);
  88 if (Ulstat(filename, &statbuf) >= 0)
  89   {
  90   /* Since the filename exists in the filesystem, we can return a
  91   non-tainted result. */
  92   *result = string_copy_taint(keystring, FALSE);
  93   return OK;
  94   }
  95
  96 if (errno == ENOENT) return FAIL;
  97
  98 save_errno = errno;
  99 *errmsg = string_sprintf("%s: lstat failed", filename);
 100 errno = save_errno;
 101 return DEFER;
 102 }
 103
 104
 105 /*************************************************
 106 *              Close entry point                 *
 107 *************************************************/
 108
 109 /* See local README for interface description */
 110
 111 void
 112 static dsearch_close(void *handle)
 113 {
 114 handle = handle;   /* Avoid compiler warning */
 115 }
 116
 117
 118 /*************************************************
 119 *         Version reporting entry point          *
 120 *************************************************/
 121
 122 /* See local README for interface description. */
 123
 124 #include "../version.h"
 125
 126 void
 127 dsearch_version_report(FILE *f)
 128 {
 129 #ifdef DYNLOOKUP
 130 fprintf(f, "Library version: dsearch: Exim version %s\n", EXIM_VERSION_STR);
 131 #endif
 132 }
 133
 134
 135 static lookup_info _lookup_info = {
 136   US"dsearch",                   /* lookup name */
 137   lookup_absfile,                /* uses absolute file name */
 138   dsearch_open,                  /* open function */
 139   dsearch_check,                 /* check function */
 140   dsearch_find,                  /* find function */
 141   dsearch_close,                 /* close function */
 142   NULL,                          /* no tidy function */
 143   NULL,                          /* no quoting function */
 144   dsearch_version_report         /* version reporting */
 145 };
 146
 147 #ifdef DYNLOOKUP
 148 #define dsearch_lookup_module_info _lookup_module_info
 149 #endif
 150
 151 static lookup_info *_lookup_list[] = { &_lookup_info };
 152 lookup_module_info dsearch_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
 153
 154 /* End of lookups/dsearch.c */