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(const uschar * dirname, uschar ** errmsg)
  29 {
  30 DIR * dp = exim_opendir(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, const uschar * filename, int modemask,
  52   uid_t * owners, gid_t * owngroups, uschar ** errmsg)
  53 {
  54 handle = handle;
  55 if (*filename == '/')
  56   return lf_check_file(-1, filename, S_IFDIR, modemask, owners, owngroups,
  57     "dsearch", errmsg) == 0;
  58 *errmsg = string_sprintf("dirname '%s' for dsearch is not absolute", filename);
  59 return FALSE;
  60 }
  61
  62
  63 /*************************************************
  64 *              Find entry point                  *
  65 *************************************************/
  66
  67 #define RET_FULL        BIT(0)
  68 #define FILTER_TYPE     BIT(1)
  69 #define FILTER_ALL      BIT(1)
  70 #define FILTER_FILE     BIT(2)
  71 #define FILTER_DIR      BIT(3)
  72 #define FILTER_SUBDIR   BIT(4)
  73
  74 /* See local README for interface description. We use lstat() instead of
  75 scanning the directory, as it is hopefully faster to let the OS do the scanning
  76 for us. */
  77
  78 static int
  79 dsearch_find(void * handle, const uschar * dirname, const uschar * keystring,
  80   int length, uschar ** result, uschar ** errmsg, uint * do_cache,
  81   const uschar * opts)
  82 {
  83 struct stat statbuf;
  84 int save_errno;
  85 uschar * filename;
  86 unsigned flags = 0;
  87
  88 handle = handle;  /* Keep picky compilers happy */
  89 length = length;
  90 do_cache = do_cache;
  91
  92 if (Ustrchr(keystring, '/') != 0)
  93   {
  94   *errmsg = string_sprintf("key for dsearch lookup contains a slash: %s",
  95     keystring);
  96   return DEFER;
  97   }
  98
  99 if (opts)
 100   {
 101   int sep = ',';
 102   uschar * ele;
 103
 104   while ((ele = string_nextinlist(&opts, &sep, NULL, 0)))
 105     if (Ustrcmp(ele, "ret=full") == 0)
 106       flags |= RET_FULL;
 107     else if (Ustrncmp(ele, "filter=", 7) == 0)
 108       {
 109       ele += 7;
 110       if (Ustrcmp(ele, "file") == 0)
 111         flags |= FILTER_TYPE | FILTER_FILE;
 112       else if (Ustrcmp(ele, "dir") == 0)
 113         flags |= FILTER_TYPE | FILTER_DIR;
 114       else if (Ustrcmp(ele, "subdir") == 0)
 115         flags |= FILTER_TYPE | FILTER_SUBDIR;   /* like dir but not "." or ".." */
 116       }
 117   }
 118
 119 filename = string_sprintf("%s/%s", dirname, keystring);
 120 if (  Ulstat(filename, &statbuf) >= 0
 121    && (  !(flags & FILTER_TYPE)
 122       || (flags & FILTER_FILE && S_ISREG(statbuf.st_mode))
 123       || (  flags & (FILTER_DIR | FILTER_SUBDIR)
 124          && S_ISDIR(statbuf.st_mode)
 125          && (  flags & FILTER_DIR
 126             || keystring[0] != '.'
 127             || keystring[1] != '.'
 128             || keystring[1] && keystring[2]
 129    )  )  )  )
 130   {
 131   /* Since the filename exists in the filesystem, we can return a
 132   non-tainted result. */
 133   *result = string_copy_taint(flags & RET_FULL ? filename : keystring, FALSE);
 134   return OK;
 135   }
 136
 137 if (errno == ENOENT) return FAIL;
 138
 139 save_errno = errno;
 140 *errmsg = string_sprintf("%s: lstat failed", filename);
 141 errno = save_errno;
 142 return DEFER;
 143 }
 144
 145
 146 /*************************************************
 147 *              Close entry point                 *
 148 *************************************************/
 149
 150 /* See local README for interface description */
 151
 152 void
 153 static dsearch_close(void *handle)
 154 {
 155 handle = handle;   /* Avoid compiler warning */
 156 }
 157
 158
 159 /*************************************************
 160 *         Version reporting entry point          *
 161 *************************************************/
 162
 163 /* See local README for interface description. */
 164
 165 #include "../version.h"
 166
 167 void
 168 dsearch_version_report(FILE *f)
 169 {
 170 #ifdef DYNLOOKUP
 171 fprintf(f, "Library version: dsearch: Exim version %s\n", EXIM_VERSION_STR);
 172 #endif
 173 }
 174
 175
 176 static lookup_info _lookup_info = {
 177   US"dsearch",                   /* lookup name */
 178   lookup_absfile,                /* uses absolute file name */
 179   dsearch_open,                  /* open function */
 180   dsearch_check,                 /* check function */
 181   dsearch_find,                  /* find function */
 182   dsearch_close,                 /* close function */
 183   NULL,                          /* no tidy function */
 184   NULL,                          /* no quoting function */
 185   dsearch_version_report         /* version reporting */
 186 };
 187
 188 #ifdef DYNLOOKUP
 189 #define dsearch_lookup_module_info _lookup_module_info
 190 #endif
 191
 192 static lookup_info *_lookup_list[] = { &_lookup_info };
 193 lookup_module_info dsearch_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
 194
 195 /* End of lookups/dsearch.c */