src/src/lookups/mysql.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 /* Thanks to Paul Kelly for contributing the original code for these
   9 functions. */
  10
  11
  12 #include "../exim.h"
  13 #include "lf_functions.h"
  14
  15 #include <mysql.h>       /* The system header */
  16
  17
  18 /* Structure and anchor for caching connections. */
  19
  20 typedef struct mysql_connection {
  21   struct mysql_connection *next;
  22   uschar  *server;
  23   MYSQL *handle;
  24 } mysql_connection;
  25
  26 static mysql_connection *mysql_connections = NULL;
  27
  28
  29
  30 /*************************************************
  31 *              Open entry point                  *
  32 *************************************************/
  33
  34 /* See local README for interface description. */
  35
  36 static void *
  37 mysql_open(uschar *filename, uschar **errmsg)
  38 {
  39 return (void *)(1);    /* Just return something non-null */
  40 }
  41
  42
  43
  44 /*************************************************
  45 *               Tidy entry point                 *
  46 *************************************************/
  47
  48 /* See local README for interface description. */
  49
  50 static void
  51 mysql_tidy(void)
  52 {
  53 mysql_connection *cn;
  54 while ((cn = mysql_connections) != NULL)
  55   {
  56   mysql_connections = cn->next;
  57   DEBUG(D_lookup) debug_printf("close MYSQL connection: %s\n", cn->server);
  58   mysql_close(cn->handle);
  59   }
  60 }
  61
  62
  63
  64 /*************************************************
  65 *        Internal search function                *
  66 *************************************************/
  67
  68 /* This function is called from the find entry point to do the search for a
  69 single server.
  70
  71 Arguments:
  72   query        the query string
  73   server       the server string
  74   resultptr    where to store the result
  75   errmsg       where to point an error message
  76   defer_break  TRUE if no more servers are to be tried after DEFER
  77   do_cache     set zero if data is changed
  78
  79 The server string is of the form "host/dbname/user/password". The host can be
  80 host:port. This string is in a nextinlist temporary buffer, so can be
  81 overwritten.
  82
  83 Returns:       OK, FAIL, or DEFER
  84 */
  85
  86 static int
  87 perform_mysql_search(const uschar *query, uschar *server, uschar **resultptr,
  88   uschar **errmsg, BOOL *defer_break, uint *do_cache)
  89 {
  90 MYSQL *mysql_handle = NULL;        /* Keep compilers happy */
  91 MYSQL_RES *mysql_result = NULL;
  92 MYSQL_ROW mysql_row_data;
  93 MYSQL_FIELD *fields;
  94
  95 int i;
  96 int ssize = 0;
  97 int offset = 0;
  98 int yield = DEFER;
  99 unsigned int num_fields;
 100 uschar *result = NULL;
 101 mysql_connection *cn;
 102 uschar *server_copy = NULL;
 103 uschar *sdata[4];
 104
 105 /* Disaggregate the parameters from the server argument. The order is host,
 106 database, user, password. We can write to the string, since it is in a
 107 nextinlist temporary buffer. The copy of the string that is used for caching
 108 has the password removed. This copy is also used for debugging output. */
 109
 110 for (i = 3; i > 0; i--)
 111   {
 112   uschar *pp = Ustrrchr(server, '/');
 113   if (pp == NULL)
 114     {
 115     *errmsg = string_sprintf("incomplete MySQL server data: %s",
 116       (i == 3)? server : server_copy);
 117     *defer_break = TRUE;
 118     return DEFER;
 119     }
 120   *pp++ = 0;
 121   sdata[i] = pp;
 122   if (i == 3) server_copy = string_copy(server);  /* sans password */
 123   }
 124 sdata[0] = server;   /* What's left at the start */
 125
 126 /* See if we have a cached connection to the server */
 127
 128 for (cn = mysql_connections; cn; cn = cn->next)
 129   if (Ustrcmp(cn->server, server_copy) == 0)
 130     {
 131     mysql_handle = cn->handle;
 132     break;
 133     }
 134
 135 /* If no cached connection, we must set one up. Mysql allows for a host name
 136 and port to be specified. It also allows the name of a Unix socket to be used.
 137 Unfortunately, this contains slashes, but its use is expected to be rare, so
 138 the rather cumbersome syntax shouldn't inconvenience too many people. We use
 139 this:  host:port(socket)[group]  where all the parts are optional.
 140 The "group" parameter specifies an option group from a MySQL option file. */
 141
 142 if (!cn)
 143   {
 144   uschar *p;
 145   uschar *socket = NULL;
 146   int port = 0;
 147   uschar *group = US"exim";
 148
 149   if ((p = Ustrchr(sdata[0], '[')))
 150     {
 151     *p++ = 0;
 152     group = p;
 153     while (*p && *p != ']') p++;
 154     *p = 0;
 155     }
 156
 157   if ((p = Ustrchr(sdata[0], '(')))
 158     {
 159     *p++ = 0;
 160     socket = p;
 161     while (*p && *p != ')') p++;
 162     *p = 0;
 163     }
 164
 165   if ((p = Ustrchr(sdata[0], ':')))
 166     {
 167     *p++ = 0;
 168     port = Uatoi(p);
 169     }
 170
 171   if (Ustrchr(sdata[0], '/'))
 172     {
 173     *errmsg = string_sprintf("unexpected slash in MySQL server hostname: %s",
 174       sdata[0]);
 175     *defer_break = TRUE;
 176     return DEFER;
 177     }
 178
 179   /* If the database is the empty string, set it NULL - the query must then
 180   define it. */
 181
 182   if (sdata[1][0] == 0) sdata[1] = NULL;
 183
 184   DEBUG(D_lookup)
 185     debug_printf("MYSQL new connection: host=%s port=%d socket=%s "
 186       "database=%s user=%s\n", sdata[0], port, socket, sdata[1], sdata[2]);
 187
 188   /* Get store for a new handle, initialize it, and connect to the server */
 189
 190   mysql_handle = store_get(sizeof(MYSQL));
 191   mysql_init(mysql_handle);
 192   mysql_options(mysql_handle, MYSQL_READ_DEFAULT_GROUP, CS group);
 193   if (mysql_real_connect(mysql_handle,
 194       /*  host        user         passwd     database */
 195       CS sdata[0], CS sdata[2], CS sdata[3], CS sdata[1],
 196       port, CS socket, CLIENT_MULTI_RESULTS) == NULL)
 197     {
 198     *errmsg = string_sprintf("MYSQL connection failed: %s",
 199       mysql_error(mysql_handle));
 200     *defer_break = FALSE;
 201     goto MYSQL_EXIT;
 202     }
 203
 204   /* Add the connection to the cache */
 205
 206   cn = store_get(sizeof(mysql_connection));
 207   cn->server = server_copy;
 208   cn->handle = mysql_handle;
 209   cn->next = mysql_connections;
 210   mysql_connections = cn;
 211   }
 212
 213 /* Else use a previously cached connection */
 214
 215 else
 216   {
 217   DEBUG(D_lookup)
 218     debug_printf("MYSQL using cached connection for %s\n", server_copy);
 219   }
 220
 221 /* Run the query */
 222
 223 if (mysql_query(mysql_handle, CS query) != 0)
 224   {
 225   *errmsg = string_sprintf("MYSQL: query failed: %s\n",
 226     mysql_error(mysql_handle));
 227   *defer_break = FALSE;
 228   goto MYSQL_EXIT;
 229   }
 230
 231 /* Pick up the result. If the query was not of the type that returns data,
 232 namely INSERT, UPDATE, or DELETE, an error occurs here. However, this situation
 233 can be detected by calling mysql_field_count(). If its result is zero, no data
 234 was expected (this is all explained clearly in the MySQL manual). In this case,
 235 we return the number of rows affected by the command. In this event, we do NOT
 236 want to cache the result; also the whole cache for the handle must be cleaned
 237 up. Setting do_cache zero requests this. */
 238
 239 if ((mysql_result = mysql_use_result(mysql_handle)) == NULL)
 240   {
 241   if ( mysql_field_count(mysql_handle) == 0 )
 242     {
 243     DEBUG(D_lookup) debug_printf("MYSQL: query was not one that returns data\n");
 244     result = string_sprintf("%d", mysql_affected_rows(mysql_handle));
 245     *do_cache = 0;
 246     goto MYSQL_EXIT;
 247     }
 248   *errmsg = string_sprintf("MYSQL: lookup result failed: %s\n",
 249     mysql_error(mysql_handle));
 250   *defer_break = FALSE;
 251   goto MYSQL_EXIT;
 252   }
 253
 254 /* Find the number of fields returned. If this is one, we don't add field
 255 names to the data. Otherwise we do. */
 256
 257 num_fields = mysql_num_fields(mysql_result);
 258
 259 /* Get the fields and construct the result string. If there is more than one
 260 row, we insert '\n' between them. */
 261
 262 fields = mysql_fetch_fields(mysql_result);
 263
 264 while ((mysql_row_data = mysql_fetch_row(mysql_result)) != NULL)
 265   {
 266   unsigned long *lengths = mysql_fetch_lengths(mysql_result);
 267
 268   if (result != NULL)
 269       result = string_cat(result, &ssize, &offset, US"\n", 1);
 270
 271   if (num_fields == 1)
 272     {
 273     if (mysql_row_data[0] != NULL)    /* NULL value yields nothing */
 274       result = string_cat(result, &ssize, &offset, US mysql_row_data[0],
 275         lengths[0]);
 276     }
 277
 278   else for (i = 0; i < num_fields; i++)
 279     {
 280     result = lf_quote(US fields[i].name, US mysql_row_data[i], lengths[i],
 281       result, &ssize, &offset);
 282     }
 283   }
 284
 285 /* more results? -1 = no, >0 = error, 0 = yes (keep looping)
 286    This is needed because of the CLIENT_MULTI_RESULTS on mysql_real_connect(),
 287    we don't expect any more results. */
 288
 289 while((i = mysql_next_result(mysql_handle)) >= 0) {
 290    if(i == 0) {   /* Just ignore more results */
 291      DEBUG(D_lookup) debug_printf("MYSQL: got unexpected more results\n");
 292      continue;
 293    }
 294
 295    *errmsg = string_sprintf("MYSQL: lookup result error when checking for more results: %s\n",
 296        mysql_error(mysql_handle));
 297    goto MYSQL_EXIT;
 298 }
 299
 300 /* If result is NULL then no data has been found and so we return FAIL.
 301 Otherwise, we must terminate the string which has been built; string_cat()
 302 always leaves enough room for a terminating zero. */
 303
 304 if (result == NULL)
 305   {
 306   yield = FAIL;
 307   *errmsg = US"MYSQL: no data found";
 308   }
 309 else
 310   {
 311   result[offset] = 0;
 312   store_reset(result + offset + 1);
 313   }
 314
 315 /* Get here by goto from various error checks and from the case where no data
 316 was read (e.g. an update query). */
 317
 318 MYSQL_EXIT:
 319
 320 /* Free mysal store for any result that was got; don't close the connection, as
 321 it is cached. */
 322
 323 if (mysql_result != NULL) mysql_free_result(mysql_result);
 324
 325 /* Non-NULL result indicates a sucessful result */
 326
 327 if (result != NULL)
 328   {
 329   *resultptr = result;
 330   return OK;
 331   }
 332 else
 333   {
 334   DEBUG(D_lookup) debug_printf("%s\n", *errmsg);
 335   return yield;      /* FAIL or DEFER */
 336   }
 337 }
 338
 339
 340
 341
 342 /*************************************************
 343 *               Find entry point                 *
 344 *************************************************/
 345
 346 /* See local README for interface description. The handle and filename
 347 arguments are not used. The code to loop through a list of servers while the
 348 query is deferred with a retryable error is now in a separate function that is
 349 shared with other SQL lookups. */
 350
 351 static int
 352 mysql_find(void *handle, uschar *filename, const uschar *query, int length,
 353   uschar **result, uschar **errmsg, uint *do_cache)
 354 {
 355 return lf_sqlperform(US"MySQL", US"mysql_servers", mysql_servers, query,
 356   result, errmsg, do_cache, perform_mysql_search);
 357 }
 358
 359
 360
 361 /*************************************************
 362 *               Quote entry point                *
 363 *************************************************/
 364
 365 /* The only characters that need to be quoted (with backslash) are newline,
 366 tab, carriage return, backspace, backslash itself, and the quote characters.
 367 Percent, and underscore and not escaped. They are only special in contexts
 368 where they can be wild cards, and this isn't usually the case for data inserted
 369 from messages, since that isn't likely to be treated as a pattern of any kind.
 370 Sadly, MySQL doesn't seem to behave like other programs. If you use something
 371 like "where id="ab\%cd" it does not treat the string as "ab%cd". So you really
 372 can't quote "on spec".
 373
 374 Arguments:
 375   s          the string to be quoted
 376   opt        additional option text or NULL if none
 377
 378 Returns:     the processed string or NULL for a bad option
 379 */
 380
 381 static uschar *
 382 mysql_quote(uschar *s, uschar *opt)
 383 {
 384 register int c;
 385 int count = 0;
 386 uschar *t = s;
 387 uschar *quoted;
 388
 389 if (opt != NULL) return NULL;     /* No options recognized */
 390
 391 while ((c = *t++) != 0)
 392   if (Ustrchr("\n\t\r\b\'\"\\", c) != NULL) count++;
 393
 394 if (count == 0) return s;
 395 t = quoted = store_get(Ustrlen(s) + count + 1);
 396
 397 while ((c = *s++) != 0)
 398   {
 399   if (Ustrchr("\n\t\r\b\'\"\\", c) != NULL)
 400     {
 401     *t++ = '\\';
 402     switch(c)
 403       {
 404       case '\n': *t++ = 'n';
 405       break;
 406       case '\t': *t++ = 't';
 407       break;
 408       case '\r': *t++ = 'r';
 409       break;
 410       case '\b': *t++ = 'b';
 411       break;
 412       default:   *t++ = c;
 413       break;
 414       }
 415     }
 416   else *t++ = c;
 417   }
 418
 419 *t = 0;
 420 return quoted;
 421 }
 422
 423
 424 /*************************************************
 425 *         Version reporting entry point          *
 426 *************************************************/
 427
 428 /* See local README for interface description. */
 429
 430 #include "../version.h"
 431
 432 void
 433 mysql_version_report(FILE *f)
 434 {
 435 fprintf(f, "Library version: MySQL: Compile: %s [%s]\n"
 436            "                        Runtime: %s\n",
 437         MYSQL_SERVER_VERSION, MYSQL_COMPILATION_COMMENT,
 438         mysql_get_client_info());
 439 #ifdef DYNLOOKUP
 440 fprintf(f, "                        Exim version %s\n", EXIM_VERSION_STR);
 441 #endif
 442 }
 443
 444 /* These are the lookup_info blocks for this driver */
 445
 446 static lookup_info mysql_lookup_info = {
 447   US"mysql",                     /* lookup name */
 448   lookup_querystyle,             /* query-style lookup */
 449   mysql_open,                    /* open function */
 450   NULL,                          /* no check function */
 451   mysql_find,                    /* find function */
 452   NULL,                          /* no close function */
 453   mysql_tidy,                    /* tidy function */
 454   mysql_quote,                   /* quoting function */
 455   mysql_version_report           /* version reporting */
 456 };
 457
 458 #ifdef DYNLOOKUP
 459 #define mysql_lookup_module_info _lookup_module_info
 460 #endif
 461
 462 static lookup_info *_lookup_list[] = { &mysql_lookup_info };
 463 lookup_module_info mysql_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
 464
 465 /* End of lookups/mysql.c */