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 == NULL)
  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 BOOL
  51 static 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 int
  69 static 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[PATH_MAX];
  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 if (!string_format(filename, sizeof(filename), "%s/%s", dirname, keystring))
  88   {
  89   *errmsg = US"path name too long";
  90   return DEFER;
  91   }
  92
  93 if (Ulstat(filename, &statbuf) >= 0)
  94   {
  95   *result = string_copy(keystring);
  96   return OK;
  97   }
  98
  99 if (errno == ENOENT) return FAIL;
 100
 101 save_errno = errno;
 102 *errmsg = string_sprintf("%s: lstat failed", filename);
 103 errno = save_errno;
 104 return DEFER;
 105 }
 106
 107
 108 /*************************************************
 109 *              Close entry point                 *
 110 *************************************************/
 111
 112 /* See local README for interface description */
 113
 114 void
 115 static dsearch_close(void *handle)
 116 {
 117 handle = handle;   /* Avoid compiler warning */
 118 }
 119
 120
 121 /*************************************************
 122 *         Version reporting entry point          *
 123 *************************************************/
 124
 125 /* See local README for interface description. */
 126
 127 #include "../version.h"
 128
 129 void
 130 dsearch_version_report(FILE *f)
 131 {
 132 #ifdef DYNLOOKUP
 133 fprintf(f, "Library version: dsearch: Exim version %s\n", EXIM_VERSION_STR);
 134 #endif
 135 }
 136
 137
 138 static lookup_info _lookup_info = {
 139   US"dsearch",                   /* lookup name */
 140   lookup_absfile,                /* uses absolute file name */
 141   dsearch_open,                  /* open function */
 142   dsearch_check,                 /* check function */
 143   dsearch_find,                  /* find function */
 144   dsearch_close,                 /* close function */
 145   NULL,                          /* no tidy function */
 146   NULL,                          /* no quoting function */
 147   dsearch_version_report         /* version reporting */
 148 };
 149
 150 #ifdef DYNLOOKUP
 151 #define dsearch_lookup_module_info _lookup_module_info
 152 #endif
 153
 154 static lookup_info *_lookup_list[] = { &_lookup_info };
 155 lookup_module_info dsearch_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
 156
 157 /* End of lookups/dsearch.c */