src/src/lookups/dbmdb.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2018 */
   6 /* Copyright (c) The Exim Maintainers 2020 */
   7 /* See the file NOTICE for conditions of use and distribution. */
   8
   9 #include "../exim.h"
  10 #include "lf_functions.h"
  11
  12
  13 /*************************************************
  14 *              Open entry point                  *
  15 *************************************************/
  16
  17 /* See local README for interface description */
  18
  19 static void *
  20 dbmdb_open(const uschar * filename, uschar ** errmsg)
  21 {
  22 uschar * dirname = string_copy(filename);
  23 uschar * s;
  24 EXIM_DB *yield = NULL;
  25
  26 if ((s = Ustrrchr(dirname, '/'))) *s = '\0';
  27 EXIM_DBOPEN(filename, dirname, O_RDONLY, 0, &yield);
  28 if (!yield)
  29   {
  30   int save_errno = errno;
  31   *errmsg = string_open_failed(errno, "%s as a %s file", filename, EXIM_DBTYPE);
  32   errno = save_errno;
  33   }
  34 return yield;
  35 }
  36
  37
  38
  39 /*************************************************
  40 *             Check entry point                  *
  41 *************************************************/
  42
  43 /* This needs to know more about the underlying files than is good for it!
  44 We need to know what the real file names are in order to check the owners and
  45 modes. If USE_DB is set, we know it is Berkeley DB, which uses an unmodified
  46 file name. If USE_TDB or USE_GDBM is set, we know it is tdb or gdbm, which do
  47 the same. Otherwise, for safety, we have to check for x.db or x.dir and x.pag.
  48 */
  49
  50 static BOOL
  51 dbmdb_check(void *handle, const uschar *filename, int modemask, uid_t *owners,
  52   gid_t *owngroups, uschar **errmsg)
  53 {
  54 int rc;
  55 handle = handle;    /* Keep picky compilers happy */
  56
  57 #if defined(USE_DB) || defined(USE_TDB) || defined(USE_GDBM)
  58 rc = lf_check_file(-1, filename, S_IFREG, modemask, owners, owngroups,
  59   "dbm", errmsg);
  60 #else
  61   {
  62   uschar filebuffer[256];
  63   (void)sprintf(CS filebuffer, "%.250s.db", filename);
  64   rc = lf_check_file(-1, filebuffer, S_IFREG, modemask, owners, owngroups,
  65     "dbm", errmsg);
  66   if (rc < 0)        /* stat() failed */
  67     {
  68     (void)sprintf(CS filebuffer, "%.250s.dir", filename);
  69     rc = lf_check_file(-1, filebuffer, S_IFREG, modemask, owners, owngroups,
  70       "dbm", errmsg);
  71     if (rc == 0)     /* x.dir was OK */
  72       {
  73       (void)sprintf(CS filebuffer, "%.250s.pag", filename);
  74       rc = lf_check_file(-1, filebuffer, S_IFREG, modemask, owners, owngroups,
  75         "dbm", errmsg);
  76       }
  77     }
  78   }
  79 #endif
  80
  81 return rc == 0;
  82 }
  83
  84
  85
  86 /*************************************************
  87 *              Find entry point                  *
  88 *************************************************/
  89
  90 /* See local README for interface description. This function adds 1 to
  91 the keylength in order to include the terminating zero. */
  92
  93 static int
  94 dbmdb_find(void * handle, const uschar * filename, const uschar * keystring,
  95   int length, uschar ** result, uschar ** errmsg, uint * do_cache,
  96   const uschar * opts)
  97 {
  98 EXIM_DB *d = (EXIM_DB *)handle;
  99 EXIM_DATUM key, data;
 100
 101 filename = filename;    /* Keep picky compilers happy */
 102 errmsg = errmsg;
 103 do_cache = do_cache;
 104
 105 EXIM_DATUM_INIT(key);               /* Some DBM libraries require datums to */
 106 EXIM_DATUM_INIT(data);              /* be cleared before use. */
 107 EXIM_DATUM_DATA(key) = CS keystring;
 108 EXIM_DATUM_SIZE(key) = length + 1;
 109
 110 if (EXIM_DBGET(d, key, data))
 111   {
 112   *result = string_copyn(US EXIM_DATUM_DATA(data), EXIM_DATUM_SIZE(data));
 113   EXIM_DATUM_FREE(data);            /* Some DBM libraries need a free() call */
 114   return OK;
 115   }
 116 return FAIL;
 117 }
 118
 119
 120
 121 /*************************************************
 122 *      Find entry point - no zero on key         *
 123 *************************************************/
 124
 125 /* See local README for interface description */
 126
 127 static int
 128 dbmnz_find(void * handle, const uschar * filename, const uschar * keystring,
 129   int length, uschar ** result, uschar ** errmsg, uint * do_cache,
 130   const uschar * opts)
 131 {
 132 return dbmdb_find(handle, filename, keystring, length-1, result, errmsg,
 133   do_cache, opts);
 134 }
 135
 136
 137
 138 /*************************************************
 139 *     Find entry point - zero-joined list key    *
 140 *************************************************/
 141
 142 /*
 143  * The parameter passed as a key is a list in normal Exim list syntax.
 144  * The elements of that list are joined together on NUL, with no trailing
 145  * NUL, to form the key.
 146  */
 147
 148 static int
 149 dbmjz_find(void * handle, const uschar * filename, const uschar * keystring,
 150   int length, uschar ** result, uschar ** errmsg, uint * do_cache,
 151   const uschar * opts)
 152 {
 153 uschar *key_item, *key_buffer, *key_p;
 154 const uschar *key_elems = keystring;
 155 int buflen, bufleft, key_item_len, sep = 0;
 156
 157 /* To a first approximation, the size of the lookup key needs to be about,
 158 or less than, the length of the delimited list passed in + 1. */
 159
 160 buflen = length + 3;
 161 key_buffer = store_get(buflen, is_tainted(keystring));
 162
 163 key_buffer[0] = '\0';
 164
 165 key_p = key_buffer;
 166 bufleft = buflen;
 167
 168 /* In all cases of an empty list item, we can set 1 and advance by 1 and then
 169 pick up the trailing NUL from the previous list item, EXCEPT when at the
 170 beginning of the output string, in which case we need to supply that NUL
 171 ourselves.  */
 172 while ((key_item = string_nextinlist(&key_elems, &sep, key_p, bufleft)) != NULL)
 173   {
 174   key_item_len = Ustrlen(key_item) + 1;
 175   if (key_item_len == 1)
 176     {
 177     key_p[0] = '\0';
 178     if (key_p == key_buffer)
 179       {
 180       key_p[1] = '\0';
 181       key_item_len += 1;
 182       }
 183     }
 184
 185   bufleft -= key_item_len;
 186   if (bufleft <= 0)
 187     {
 188     /* The string_nextinlist() will stop at buffer size, but we should always
 189     have at least 1 character extra, so some assumption has failed. */
 190     *errmsg = string_copy(US"Ran out of buffer space for joining elements");
 191     return DEFER;
 192     }
 193   key_p += key_item_len;
 194   }
 195
 196 if (key_p == key_buffer)
 197   {
 198   *errmsg = string_copy(US"empty list key");
 199   return FAIL;
 200   }
 201
 202 /* We do not pass in the final NULL; if needed, the list should include an
 203 empty element to put one in. Boundary: key length 1, is a NULL */
 204 key_item_len = key_p - key_buffer - 1;
 205
 206 DEBUG(D_lookup) debug_printf_indent("NUL-joined key length: %d\n", key_item_len);
 207
 208 /* beware that dbmdb_find() adds 1 to length to get back terminating NUL, so
 209 because we've calculated the real length, we need to subtract one more here */
 210
 211 return dbmdb_find(handle, filename, key_buffer, key_item_len - 1,
 212     result, errmsg, do_cache, opts);
 213 }
 214
 215
 216
 217 /*************************************************
 218 *              Close entry point                 *
 219 *************************************************/
 220
 221 /* See local README for interface description */
 222
 223 void
 224 static dbmdb_close(void *handle)
 225 {
 226 EXIM_DBCLOSE((EXIM_DB *)handle);
 227 }
 228
 229
 230
 231 /*************************************************
 232 *         Version reporting entry point          *
 233 *************************************************/
 234
 235 /* See local README for interface description. */
 236
 237 #include "../version.h"
 238
 239 void
 240 dbm_version_report(FILE *f)
 241 {
 242 #ifdef DYNLOOKUP
 243 fprintf(f, "Library version: DBM: Exim version %s\n", EXIM_VERSION_STR);
 244 #endif
 245 }
 246
 247
 248 lookup_info dbm_lookup_info = {
 249   .name = US"dbm",                      /* lookup name */
 250   .type = lookup_absfile,               /* uses absolute file name */
 251   .open = dbmdb_open,                   /* open function */
 252   .check = dbmdb_check,                 /* check function */
 253   .find = dbmdb_find,                   /* find function */
 254   .close = dbmdb_close,                 /* close function */
 255   .tidy = NULL,                         /* no tidy function */
 256   .quote = NULL,                        /* no quoting function */
 257   .version_report = dbm_version_report             /* version reporting */
 258 };
 259
 260 lookup_info dbmz_lookup_info = {
 261   .name = US"dbmnz",                    /* lookup name */
 262   .type = lookup_absfile,               /* uses absolute file name */
 263   .open = dbmdb_open,                   /* sic */     /* open function */
 264   .check = dbmdb_check,                 /* sic */     /* check function */
 265   .find = dbmnz_find,                   /* find function */
 266   .close = dbmdb_close,                 /* sic */     /* close function */
 267   .tidy = NULL,                         /* no tidy function */
 268   .quote = NULL,                        /* no quoting function */
 269   .version_report = NULL                           /* no version reporting (redundant) */
 270 };
 271
 272 lookup_info dbmjz_lookup_info = {
 273   .name = US"dbmjz",                    /* lookup name */
 274   .type = lookup_absfile,               /* uses absolute file name */
 275   .open = dbmdb_open,                   /* sic */     /* open function */
 276   .check = dbmdb_check,                 /* sic */     /* check function */
 277   .find = dbmjz_find,                   /* find function */
 278   .close = dbmdb_close,                 /* sic */     /* close function */
 279   .tidy = NULL,                         /* no tidy function */
 280   .quote = NULL,                        /* no quoting function */
 281   .version_report = NULL                           /* no version reporting (redundant) */
 282 };
 283
 284 #ifdef DYNLOOKUP
 285 #define dbmdb_lookup_module_info _lookup_module_info
 286 #endif
 287
 288 static lookup_info *_lookup_list[] = { &dbm_lookup_info, &dbmz_lookup_info, &dbmjz_lookup_info };
 289 lookup_module_info dbmdb_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 3 };
 290
 291 /* End of lookups/dbmdb.c */