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 /* We define symbols for *_VERSION_ID (numeric), *_VERSION_STR (char*)
  18 and *_BASE_STR (char*). It's a bit of guesswork. Especially for mariadb
  19 with versions before 10.2, as they do not define there there specific symbols.
  20 */
  21
  22 // Newer (>= 10.2) MariaDB
  23 #if defined                   MARIADB_VERSION_ID
  24 #define EXIM_MxSQL_VERSION_ID MARIADB_VERSION_ID
  25
  26 // MySQL defines MYSQL_VERSION_ID, and MariaDB does so
  27 // https://dev.mysql.com/doc/refman/5.7/en/c-api-server-client-versions.html
  28 #elif defined                 LIBMYSQL_VERSION_ID
  29 #define EXIM_MxSQL_VERSION_ID LIBMYSQL_VERSION_ID
  30 #elif defined                 MYSQL_VERSION_ID
  31 #define EXIM_MxSQL_VERSION_ID MYSQL_VERSION_ID
  32
  33 #else
  34 #define EXIM_MYSQL_VERSION_ID  0
  35 #endif
  36
  37 // Newer (>= 10.2) MariaDB
  38 #ifdef                         MARIADB_CLIENT_VERSION_STR
  39 #define EXIM_MxSQL_VERSION_STR MARIADB_CLIENT_VERSION_STR
  40
  41 // Mysql uses MYSQL_SERVER_VERSION
  42 #elif defined                  LIBMYSQL_VERSION
  43 #define EXIM_MxSQL_VERSION_STR LIBMYSQL_VERSION
  44 #elif defined                  MYSQL_SERVER_VERSION
  45 #define EXIM_MxSQL_VERSION_STR MYSQL_SERVER_VERSION
  46
  47 #else
  48 #define EXIM_MxSQL_VERSION_STR  "N.A."
  49 #endif
  50
  51 #if defined                 MARIADB_BASE_VERSION
  52 #define EXIM_MxSQL_BASE_STR MARIADB_BASE_VERSION
  53
  54 #elif defined               MARIADB_PACKAGE_VERSION
  55 #define EXIM_MxSQL_BASE_STR "mariadb"
  56
  57 #elif defined               MYSQL_BASE_VERSION
  58 #define EXIM_MxSQL_BASE_STR MYSQL_BASE_VERSION
  59
  60 #else
  61 #define EXIM_MxSQL_BASE_STR  "n.A."
  62 #endif
  63
  64
  65 /* Structure and anchor for caching connections. */
  66
  67 typedef struct mysql_connection {
  68   struct mysql_connection *next;
  69   uschar  *server;
  70   MYSQL *handle;
  71 } mysql_connection;
  72
  73 static mysql_connection *mysql_connections = NULL;
  74
  75
  76
  77 /*************************************************
  78 *              Open entry point                  *
  79 *************************************************/
  80
  81 /* See local README for interface description. */
  82
  83 static void *
  84 mysql_open(uschar *filename, uschar **errmsg)
  85 {
  86 return (void *)(1);    /* Just return something non-null */
  87 }
  88
  89
  90
  91 /*************************************************
  92 *               Tidy entry point                 *
  93 *************************************************/
  94
  95 /* See local README for interface description. */
  96
  97 static void
  98 mysql_tidy(void)
  99 {
 100 mysql_connection *cn;
 101 while ((cn = mysql_connections) != NULL)
 102   {
 103   mysql_connections = cn->next;
 104   DEBUG(D_lookup) debug_printf("close MYSQL connection: %s\n", cn->server);
 105   mysql_close(cn->handle);
 106   }
 107 }
 108
 109
 110
 111 /*************************************************
 112 *        Internal search function                *
 113 *************************************************/
 114
 115 /* This function is called from the find entry point to do the search for a
 116 single server.
 117
 118 Arguments:
 119   query        the query string
 120   server       the server string
 121   resultptr    where to store the result
 122   errmsg       where to point an error message
 123   defer_break  TRUE if no more servers are to be tried after DEFER
 124   do_cache     set zero if data is changed
 125
 126 The server string is of the form "host/dbname/user/password". The host can be
 127 host:port. This string is in a nextinlist temporary buffer, so can be
 128 overwritten.
 129
 130 Returns:       OK, FAIL, or DEFER
 131 */
 132
 133 static int
 134 perform_mysql_search(const uschar *query, uschar *server, uschar **resultptr,
 135   uschar **errmsg, BOOL *defer_break, uint *do_cache)
 136 {
 137 MYSQL *mysql_handle = NULL;        /* Keep compilers happy */
 138 MYSQL_RES *mysql_result = NULL;
 139 MYSQL_ROW mysql_row_data;
 140 MYSQL_FIELD *fields;
 141
 142 int i;
 143 int ssize = 0;
 144 int offset = 0;
 145 int yield = DEFER;
 146 unsigned int num_fields;
 147 uschar *result = NULL;
 148 mysql_connection *cn;
 149 uschar *server_copy = NULL;
 150 uschar *sdata[4];
 151
 152 /* Disaggregate the parameters from the server argument. The order is host,
 153 database, user, password. We can write to the string, since it is in a
 154 nextinlist temporary buffer. The copy of the string that is used for caching
 155 has the password removed. This copy is also used for debugging output. */
 156
 157 for (i = 3; i > 0; i--)
 158   {
 159   uschar *pp = Ustrrchr(server, '/');
 160   if (pp == NULL)
 161     {
 162     *errmsg = string_sprintf("incomplete MySQL server data: %s",
 163       (i == 3)? server : server_copy);
 164     *defer_break = TRUE;
 165     return DEFER;
 166     }
 167   *pp++ = 0;
 168   sdata[i] = pp;
 169   if (i == 3) server_copy = string_copy(server);  /* sans password */
 170   }
 171 sdata[0] = server;   /* What's left at the start */
 172
 173 /* See if we have a cached connection to the server */
 174
 175 for (cn = mysql_connections; cn; cn = cn->next)
 176   if (Ustrcmp(cn->server, server_copy) == 0)
 177     {
 178     mysql_handle = cn->handle;
 179     break;
 180     }
 181
 182 /* If no cached connection, we must set one up. Mysql allows for a host name
 183 and port to be specified. It also allows the name of a Unix socket to be used.
 184 Unfortunately, this contains slashes, but its use is expected to be rare, so
 185 the rather cumbersome syntax shouldn't inconvenience too many people. We use
 186 this:  host:port(socket)[group]  where all the parts are optional.
 187 The "group" parameter specifies an option group from a MySQL option file. */
 188
 189 if (!cn)
 190   {
 191   uschar *p;
 192   uschar *socket = NULL;
 193   int port = 0;
 194   uschar *group = US"exim";
 195
 196   if ((p = Ustrchr(sdata[0], '[')))
 197     {
 198     *p++ = 0;
 199     group = p;
 200     while (*p && *p != ']') p++;
 201     *p = 0;
 202     }
 203
 204   if ((p = Ustrchr(sdata[0], '(')))
 205     {
 206     *p++ = 0;
 207     socket = p;
 208     while (*p && *p != ')') p++;
 209     *p = 0;
 210     }
 211
 212   if ((p = Ustrchr(sdata[0], ':')))
 213     {
 214     *p++ = 0;
 215     port = Uatoi(p);
 216     }
 217
 218   if (Ustrchr(sdata[0], '/'))
 219     {
 220     *errmsg = string_sprintf("unexpected slash in MySQL server hostname: %s",
 221       sdata[0]);
 222     *defer_break = TRUE;
 223     return DEFER;
 224     }
 225
 226   /* If the database is the empty string, set it NULL - the query must then
 227   define it. */
 228
 229   if (sdata[1][0] == 0) sdata[1] = NULL;
 230
 231   DEBUG(D_lookup)
 232     debug_printf("MYSQL new connection: host=%s port=%d socket=%s "
 233       "database=%s user=%s\n", sdata[0], port, socket, sdata[1], sdata[2]);
 234
 235   /* Get store for a new handle, initialize it, and connect to the server */
 236
 237   mysql_handle = store_get(sizeof(MYSQL));
 238   mysql_init(mysql_handle);
 239   mysql_options(mysql_handle, MYSQL_READ_DEFAULT_GROUP, CS group);
 240   if (mysql_real_connect(mysql_handle,
 241       /*  host        user         passwd     database */
 242       CS sdata[0], CS sdata[2], CS sdata[3], CS sdata[1],
 243       port, CS socket, CLIENT_MULTI_RESULTS) == NULL)
 244     {
 245     *errmsg = string_sprintf("MYSQL connection failed: %s",
 246       mysql_error(mysql_handle));
 247     *defer_break = FALSE;
 248     goto MYSQL_EXIT;
 249     }
 250
 251   /* Add the connection to the cache */
 252
 253   cn = store_get(sizeof(mysql_connection));
 254   cn->server = server_copy;
 255   cn->handle = mysql_handle;
 256   cn->next = mysql_connections;
 257   mysql_connections = cn;
 258   }
 259
 260 /* Else use a previously cached connection */
 261
 262 else
 263   {
 264   DEBUG(D_lookup)
 265     debug_printf("MYSQL using cached connection for %s\n", server_copy);
 266   }
 267
 268 /* Run the query */
 269
 270 if (mysql_query(mysql_handle, CS query) != 0)
 271   {
 272   *errmsg = string_sprintf("MYSQL: query failed: %s\n",
 273     mysql_error(mysql_handle));
 274   *defer_break = FALSE;
 275   goto MYSQL_EXIT;
 276   }
 277
 278 /* Pick up the result. If the query was not of the type that returns data,
 279 namely INSERT, UPDATE, or DELETE, an error occurs here. However, this situation
 280 can be detected by calling mysql_field_count(). If its result is zero, no data
 281 was expected (this is all explained clearly in the MySQL manual). In this case,
 282 we return the number of rows affected by the command. In this event, we do NOT
 283 want to cache the result; also the whole cache for the handle must be cleaned
 284 up. Setting do_cache zero requests this. */
 285
 286 if ((mysql_result = mysql_use_result(mysql_handle)) == NULL)
 287   {
 288   if ( mysql_field_count(mysql_handle) == 0 )
 289     {
 290     DEBUG(D_lookup) debug_printf("MYSQL: query was not one that returns data\n");
 291     result = string_sprintf("%d", mysql_affected_rows(mysql_handle));
 292     *do_cache = 0;
 293     goto MYSQL_EXIT;
 294     }
 295   *errmsg = string_sprintf("MYSQL: lookup result failed: %s\n",
 296     mysql_error(mysql_handle));
 297   *defer_break = FALSE;
 298   goto MYSQL_EXIT;
 299   }
 300
 301 /* Find the number of fields returned. If this is one, we don't add field
 302 names to the data. Otherwise we do. */
 303
 304 num_fields = mysql_num_fields(mysql_result);
 305
 306 /* Get the fields and construct the result string. If there is more than one
 307 row, we insert '\n' between them. */
 308
 309 fields = mysql_fetch_fields(mysql_result);
 310
 311 while ((mysql_row_data = mysql_fetch_row(mysql_result)) != NULL)
 312   {
 313   unsigned long *lengths = mysql_fetch_lengths(mysql_result);
 314
 315   if (result != NULL)
 316       result = string_catn(result, &ssize, &offset, US"\n", 1);
 317
 318   if (num_fields == 1)
 319     {
 320     if (mysql_row_data[0] != NULL)    /* NULL value yields nothing */
 321       result = string_catn(result, &ssize, &offset, US mysql_row_data[0],
 322         lengths[0]);
 323     }
 324
 325   else for (i = 0; i < num_fields; i++)
 326     {
 327     result = lf_quote(US fields[i].name, US mysql_row_data[i], lengths[i],
 328       result, &ssize, &offset);
 329     }
 330   }
 331
 332 /* more results? -1 = no, >0 = error, 0 = yes (keep looping)
 333    This is needed because of the CLIENT_MULTI_RESULTS on mysql_real_connect(),
 334    we don't expect any more results. */
 335
 336 while((i = mysql_next_result(mysql_handle)) >= 0) {
 337    if(i == 0) {   /* Just ignore more results */
 338      DEBUG(D_lookup) debug_printf("MYSQL: got unexpected more results\n");
 339      continue;
 340    }
 341
 342    *errmsg = string_sprintf("MYSQL: lookup result error when checking for more results: %s\n",
 343        mysql_error(mysql_handle));
 344    goto MYSQL_EXIT;
 345 }
 346
 347 /* If result is NULL then no data has been found and so we return FAIL.
 348 Otherwise, we must terminate the string which has been built; string_cat()
 349 always leaves enough room for a terminating zero. */
 350
 351 if (result == NULL)
 352   {
 353   yield = FAIL;
 354   *errmsg = US"MYSQL: no data found";
 355   }
 356 else
 357   {
 358   result[offset] = 0;
 359   store_reset(result + offset + 1);
 360   }
 361
 362 /* Get here by goto from various error checks and from the case where no data
 363 was read (e.g. an update query). */
 364
 365 MYSQL_EXIT:
 366
 367 /* Free mysal store for any result that was got; don't close the connection, as
 368 it is cached. */
 369
 370 if (mysql_result != NULL) mysql_free_result(mysql_result);
 371
 372 /* Non-NULL result indicates a successful result */
 373
 374 if (result != NULL)
 375   {
 376   *resultptr = result;
 377   return OK;
 378   }
 379 else
 380   {
 381   DEBUG(D_lookup) debug_printf("%s\n", *errmsg);
 382   return yield;      /* FAIL or DEFER */
 383   }
 384 }
 385
 386
 387
 388
 389 /*************************************************
 390 *               Find entry point                 *
 391 *************************************************/
 392
 393 /* See local README for interface description. The handle and filename
 394 arguments are not used. The code to loop through a list of servers while the
 395 query is deferred with a retryable error is now in a separate function that is
 396 shared with other SQL lookups. */
 397
 398 static int
 399 mysql_find(void *handle, uschar *filename, const uschar *query, int length,
 400   uschar **result, uschar **errmsg, uint *do_cache)
 401 {
 402 return lf_sqlperform(US"MySQL", US"mysql_servers", mysql_servers, query,
 403   result, errmsg, do_cache, perform_mysql_search);
 404 }
 405
 406
 407
 408 /*************************************************
 409 *               Quote entry point                *
 410 *************************************************/
 411
 412 /* The only characters that need to be quoted (with backslash) are newline,
 413 tab, carriage return, backspace, backslash itself, and the quote characters.
 414 Percent, and underscore and not escaped. They are only special in contexts
 415 where they can be wild cards, and this isn't usually the case for data inserted
 416 from messages, since that isn't likely to be treated as a pattern of any kind.
 417 Sadly, MySQL doesn't seem to behave like other programs. If you use something
 418 like "where id="ab\%cd" it does not treat the string as "ab%cd". So you really
 419 can't quote "on spec".
 420
 421 Arguments:
 422   s          the string to be quoted
 423   opt        additional option text or NULL if none
 424
 425 Returns:     the processed string or NULL for a bad option
 426 */
 427
 428 static uschar *
 429 mysql_quote(uschar *s, uschar *opt)
 430 {
 431 register int c;
 432 int count = 0;
 433 uschar *t = s;
 434 uschar *quoted;
 435
 436 if (opt != NULL) return NULL;     /* No options recognized */
 437
 438 while ((c = *t++) != 0)
 439   if (Ustrchr("\n\t\r\b\'\"\\", c) != NULL) count++;
 440
 441 if (count == 0) return s;
 442 t = quoted = store_get(Ustrlen(s) + count + 1);
 443
 444 while ((c = *s++) != 0)
 445   {
 446   if (Ustrchr("\n\t\r\b\'\"\\", c) != NULL)
 447     {
 448     *t++ = '\\';
 449     switch(c)
 450       {
 451       case '\n': *t++ = 'n';
 452       break;
 453       case '\t': *t++ = 't';
 454       break;
 455       case '\r': *t++ = 'r';
 456       break;
 457       case '\b': *t++ = 'b';
 458       break;
 459       default:   *t++ = c;
 460       break;
 461       }
 462     }
 463   else *t++ = c;
 464   }
 465
 466 *t = 0;
 467 return quoted;
 468 }
 469
 470
 471 /*************************************************
 472 *         Version reporting entry point          *
 473 *************************************************/
 474
 475 /* See local README for interface description. */
 476
 477 #include "../version.h"
 478
 479 void
 480 mysql_version_report(FILE *f)
 481 {
 482 fprintf(f, "Library version: MySQL: Compile: %lu %s [%s]\n"
 483            "                        Runtime: %lu %s\n",
 484         (long)EXIM_MxSQL_VERSION_ID, EXIM_MxSQL_VERSION_STR, EXIM_MxSQL_BASE_STR,
 485         mysql_get_client_version(), mysql_get_client_info());
 486 #ifdef DYNLOOKUP
 487 fprintf(f, "                        Exim version %s\n", EXIM_VERSION_STR);
 488 #endif
 489 }
 490
 491 /* These are the lookup_info blocks for this driver */
 492
 493 static lookup_info mysql_lookup_info = {
 494   US"mysql",                     /* lookup name */
 495   lookup_querystyle,             /* query-style lookup */
 496   mysql_open,                    /* open function */
 497   NULL,                          /* no check function */
 498   mysql_find,                    /* find function */
 499   NULL,                          /* no close function */
 500   mysql_tidy,                    /* tidy function */
 501   mysql_quote,                   /* quoting function */
 502   mysql_version_report           /* version reporting */
 503 };
 504
 505 #ifdef DYNLOOKUP
 506 #define mysql_lookup_module_info _lookup_module_info
 507 #endif
 508
 509 static lookup_info *_lookup_list[] = { &mysql_lookup_info };
 510 lookup_module_info mysql_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
 511
 512 /* End of lookups/mysql.c */