src/src/lookups/mysql.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 /* Thanks to Paul Kelly for contributing the original code for these
  10 functions. */
  11
  12
  13 #include "../exim.h"
  14 #include "lf_functions.h"
  15
  16 #include <mysql.h>       /* The system header */
  17
  18 /* We define symbols for *_VERSION_ID (numeric), *_VERSION_STR (char*)
  19 and *_BASE_STR (char*). It's a bit of guesswork. Especially for mariadb
  20 with versions before 10.2, as they do not define there there specific symbols.
  21 */
  22
  23 /* Newer (>= 10.2) MariaDB */
  24 #if defined                   MARIADB_VERSION_ID
  25 #define EXIM_MxSQL_VERSION_ID MARIADB_VERSION_ID
  26
  27 /* MySQL defines MYSQL_VERSION_ID, and MariaDB does so */
  28 /* https://dev.mysql.com/doc/refman/5.7/en/c-api-server-client-versions.html */
  29 #elif defined                 LIBMYSQL_VERSION_ID
  30 #define EXIM_MxSQL_VERSION_ID LIBMYSQL_VERSION_ID
  31 #elif defined                 MYSQL_VERSION_ID
  32 #define EXIM_MxSQL_VERSION_ID MYSQL_VERSION_ID
  33
  34 #else
  35 #define EXIM_MYSQL_VERSION_ID  0
  36 #endif
  37
  38 /* Newer (>= 10.2) MariaDB */
  39 #ifdef                         MARIADB_CLIENT_VERSION_STR
  40 #define EXIM_MxSQL_VERSION_STR MARIADB_CLIENT_VERSION_STR
  41
  42 /* Mysql uses MYSQL_SERVER_VERSION */
  43 #elif defined                  LIBMYSQL_VERSION
  44 #define EXIM_MxSQL_VERSION_STR LIBMYSQL_VERSION
  45 #elif defined                  MYSQL_SERVER_VERSION
  46 #define EXIM_MxSQL_VERSION_STR MYSQL_SERVER_VERSION
  47
  48 #else
  49 #define EXIM_MxSQL_VERSION_STR  "unknown"
  50 #endif
  51
  52 #if defined                 MARIADB_BASE_VERSION
  53 #define EXIM_MxSQL_BASE_STR MARIADB_BASE_VERSION
  54
  55 #elif defined               MARIADB_PACKAGE_VERSION
  56 #define EXIM_MxSQL_BASE_STR "mariadb"
  57
  58 #elif defined               MYSQL_BASE_VERSION
  59 #define EXIM_MxSQL_BASE_STR MYSQL_BASE_VERSION
  60
  61 #else
  62 #define EXIM_MxSQL_BASE_STR  "n.A."
  63 #endif
  64
  65
  66 /* Structure and anchor for caching connections. */
  67
  68 typedef struct mysql_connection {
  69   struct mysql_connection *next;
  70   uschar  *server;
  71   MYSQL *handle;
  72 } mysql_connection;
  73
  74 static mysql_connection *mysql_connections = NULL;
  75
  76
  77
  78 /*************************************************
  79 *              Open entry point                  *
  80 *************************************************/
  81
  82 /* See local README for interface description. */
  83
  84 static void *
  85 mysql_open(const uschar * filename, uschar ** errmsg)
  86 {
  87 return (void *)(1);    /* Just return something non-null */
  88 }
  89
  90
  91
  92 /*************************************************
  93 *               Tidy entry point                 *
  94 *************************************************/
  95
  96 /* See local README for interface description. */
  97
  98 static void
  99 mysql_tidy(void)
 100 {
 101 mysql_connection *cn;
 102 while ((cn = mysql_connections) != NULL)
 103   {
 104   mysql_connections = cn->next;
 105   DEBUG(D_lookup) debug_printf_indent("close MYSQL connection: %s\n", cn->server);
 106   mysql_close(cn->handle);
 107   }
 108 }
 109
 110
 111
 112 /*************************************************
 113 *        Internal search function                *
 114 *************************************************/
 115
 116 /* This function is called from the find entry point to do the search for a
 117 single server.
 118
 119 Arguments:
 120   query        the query string
 121   server       the server string
 122   resultptr    where to store the result
 123   errmsg       where to point an error message
 124   defer_break  TRUE if no more servers are to be tried after DEFER
 125   do_cache     set zero if data is changed
 126   opts         options
 127
 128 The server string is of the form "host/dbname/user/password". The host can be
 129 host:port. This string is in a nextinlist temporary buffer, so can be
 130 overwritten.
 131
 132 Returns:       OK, FAIL, or DEFER
 133 */
 134
 135 static int
 136 perform_mysql_search(const uschar *query, uschar *server, uschar **resultptr,
 137   uschar **errmsg, BOOL *defer_break, uint *do_cache, const uschar * opts)
 138 {
 139 MYSQL *mysql_handle = NULL;        /* Keep compilers happy */
 140 MYSQL_RES *mysql_result = NULL;
 141 MYSQL_ROW mysql_row_data;
 142 MYSQL_FIELD *fields;
 143
 144 int i;
 145 int yield = DEFER;
 146 unsigned int num_fields;
 147 gstring * 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 (int i = 3; i > 0; i--)
 158   {
 159   uschar *pp = Ustrrchr(server, '/');
 160   if (!pp)
 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     { mysql_handle = cn->handle; break; }
 178
 179 /* If no cached connection, we must set one up. Mysql allows for a host name
 180 and port to be specified. It also allows the name of a Unix socket to be used.
 181 Unfortunately, this contains slashes, but its use is expected to be rare, so
 182 the rather cumbersome syntax shouldn't inconvenience too many people. We use
 183 this:  host:port(socket)[group]  where all the parts are optional.
 184 The "group" parameter specifies an option group from a MySQL option file. */
 185
 186 if (!cn)
 187   {
 188   uschar *p;
 189   uschar *socket = NULL;
 190   int port = 0;
 191   uschar *group = US"exim";
 192
 193   if ((p = Ustrchr(sdata[0], '[')))
 194     {
 195     *p++ = 0;
 196     group = p;
 197     while (*p && *p != ']') p++;
 198     *p = 0;
 199     }
 200
 201   if ((p = Ustrchr(sdata[0], '(')))
 202     {
 203     *p++ = 0;
 204     socket = p;
 205     while (*p && *p != ')') p++;
 206     *p = 0;
 207     }
 208
 209   if ((p = Ustrchr(sdata[0], ':')))
 210     {
 211     *p++ = 0;
 212     port = Uatoi(p);
 213     }
 214
 215   if (Ustrchr(sdata[0], '/'))
 216     {
 217     *errmsg = string_sprintf("unexpected slash in MySQL server hostname: %s",
 218       sdata[0]);
 219     *defer_break = TRUE;
 220     return DEFER;
 221     }
 222
 223   /* If the database is the empty string, set it NULL - the query must then
 224   define it. */
 225
 226   if (sdata[1][0] == 0) sdata[1] = NULL;
 227
 228   DEBUG(D_lookup)
 229     debug_printf_indent("MYSQL new connection: host=%s port=%d socket=%s "
 230       "database=%s user=%s\n", sdata[0], port, socket, sdata[1], sdata[2]);
 231
 232   /* Get store for a new handle, initialize it, and connect to the server */
 233
 234   mysql_handle = store_get(sizeof(MYSQL), FALSE);
 235   mysql_init(mysql_handle);
 236   mysql_options(mysql_handle, MYSQL_READ_DEFAULT_GROUP, CS group);
 237   if (mysql_real_connect(mysql_handle,
 238       /*  host        user         passwd     database */
 239       CS sdata[0], CS sdata[2], CS sdata[3], CS sdata[1],
 240       port, CS socket, CLIENT_MULTI_RESULTS) == NULL)
 241     {
 242     *errmsg = string_sprintf("MYSQL connection failed: %s",
 243       mysql_error(mysql_handle));
 244     *defer_break = FALSE;
 245     goto MYSQL_EXIT;
 246     }
 247
 248   /* Add the connection to the cache */
 249
 250   cn = store_get(sizeof(mysql_connection), FALSE);
 251   cn->server = server_copy;
 252   cn->handle = mysql_handle;
 253   cn->next = mysql_connections;
 254   mysql_connections = cn;
 255   }
 256
 257 /* Else use a previously cached connection */
 258
 259 else
 260   {
 261   DEBUG(D_lookup)
 262     debug_printf_indent("MYSQL using cached connection for %s\n", server_copy);
 263   }
 264
 265 /* Run the query */
 266
 267 if (mysql_query(mysql_handle, CS query) != 0)
 268   {
 269   *errmsg = string_sprintf("MYSQL: query failed: %s\n",
 270     mysql_error(mysql_handle));
 271   *defer_break = FALSE;
 272   goto MYSQL_EXIT;
 273   }
 274
 275 /* Pick up the result. If the query was not of the type that returns data,
 276 namely INSERT, UPDATE, or DELETE, an error occurs here. However, this situation
 277 can be detected by calling mysql_field_count(). If its result is zero, no data
 278 was expected (this is all explained clearly in the MySQL manual). In this case,
 279 we return the number of rows affected by the command. In this event, we do NOT
 280 want to cache the result; also the whole cache for the handle must be cleaned
 281 up. Setting do_cache zero requests this. */
 282
 283 if (!(mysql_result = mysql_use_result(mysql_handle)))
 284   {
 285   if (mysql_field_count(mysql_handle) == 0)
 286     {
 287     DEBUG(D_lookup) debug_printf_indent("MYSQL: query was not one that returns data\n");
 288     result = string_cat(result,
 289                string_sprintf("%d", mysql_affected_rows(mysql_handle)));
 290     *do_cache = 0;
 291     goto MYSQL_EXIT;
 292     }
 293   *errmsg = string_sprintf("MYSQL: lookup result failed: %s\n",
 294     mysql_error(mysql_handle));
 295   *defer_break = FALSE;
 296   goto MYSQL_EXIT;
 297   }
 298
 299 /* Find the number of fields returned. If this is one, we don't add field
 300 names to the data. Otherwise we do. */
 301
 302 num_fields = mysql_num_fields(mysql_result);
 303
 304 /* Get the fields and construct the result string. If there is more than one
 305 row, we insert '\n' between them. */
 306
 307 fields = mysql_fetch_fields(mysql_result);
 308
 309 while ((mysql_row_data = mysql_fetch_row(mysql_result)))
 310   {
 311   unsigned long *lengths = mysql_fetch_lengths(mysql_result);
 312
 313   if (result)
 314     result = string_catn(result, US"\n", 1);
 315
 316   if (num_fields != 1)
 317     for (int i = 0; i < num_fields; i++)
 318       result = lf_quote(US fields[i].name, US mysql_row_data[i], lengths[i],
 319                         result);
 320
 321   else if (mysql_row_data[0] != NULL)    /* NULL value yields nothing */
 322       result = string_catn(result, US mysql_row_data[0], lengths[0]);
 323   }
 324
 325 /* more results? -1 = no, >0 = error, 0 = yes (keep looping)
 326    This is needed because of the CLIENT_MULTI_RESULTS on mysql_real_connect(),
 327    we don't expect any more results. */
 328
 329 while((i = mysql_next_result(mysql_handle)) >= 0)
 330   if(i != 0)
 331     {
 332     *errmsg = string_sprintf(
 333           "MYSQL: lookup result error when checking for more results: %s\n",
 334           mysql_error(mysql_handle));
 335     goto MYSQL_EXIT;
 336     }
 337   else  /* just ignore more results */
 338     DEBUG(D_lookup) debug_printf_indent("MYSQL: got unexpected more results\n");
 339
 340 /* If result is NULL then no data has been found and so we return FAIL.
 341 Otherwise, we must terminate the string which has been built; string_cat()
 342 always leaves enough room for a terminating zero. */
 343
 344 if (!result)
 345   {
 346   yield = FAIL;
 347   *errmsg = US"MYSQL: no data found";
 348   }
 349
 350 /* Get here by goto from various error checks and from the case where no data
 351 was read (e.g. an update query). */
 352
 353 MYSQL_EXIT:
 354
 355 /* Free mysal store for any result that was got; don't close the connection, as
 356 it is cached. */
 357
 358 if (mysql_result) mysql_free_result(mysql_result);
 359
 360 /* Non-NULL result indicates a successful result */
 361
 362 if (result)
 363   {
 364   *resultptr = string_from_gstring(result);
 365   gstring_release_unused(result);
 366   return OK;
 367   }
 368 else
 369   {
 370   DEBUG(D_lookup) debug_printf_indent("%s\n", *errmsg);
 371   return yield;      /* FAIL or DEFER */
 372   }
 373 }
 374
 375
 376
 377
 378 /*************************************************
 379 *               Find entry point                 *
 380 *************************************************/
 381
 382 /* See local README for interface description. The handle and filename
 383 arguments are not used. The code to loop through a list of servers while the
 384 query is deferred with a retryable error is now in a separate function that is
 385 shared with other SQL lookups. */
 386
 387 static int
 388 mysql_find(void * handle, const uschar * filename, const uschar * query,
 389   int length, uschar ** result, uschar ** errmsg, uint * do_cache,
 390   const uschar * opts)
 391 {
 392 return lf_sqlperform(US"MySQL", US"mysql_servers", mysql_servers, query,
 393   result, errmsg, do_cache, opts, perform_mysql_search);
 394 }
 395
 396
 397
 398 /*************************************************
 399 *               Quote entry point                *
 400 *************************************************/
 401
 402 /* The only characters that need to be quoted (with backslash) are newline,
 403 tab, carriage return, backspace, backslash itself, and the quote characters.
 404 Percent, and underscore and not escaped. They are only special in contexts
 405 where they can be wild cards, and this isn't usually the case for data inserted
 406 from messages, since that isn't likely to be treated as a pattern of any kind.
 407 Sadly, MySQL doesn't seem to behave like other programs. If you use something
 408 like "where id="ab\%cd" it does not treat the string as "ab%cd". So you really
 409 can't quote "on spec".
 410
 411 Arguments:
 412   s          the string to be quoted
 413   opt        additional option text or NULL if none
 414
 415 Returns:     the processed string or NULL for a bad option
 416 */
 417
 418 static uschar *
 419 mysql_quote(uschar *s, uschar *opt)
 420 {
 421 register int c;
 422 int count = 0;
 423 uschar *t = s;
 424 uschar *quoted;
 425
 426 if (opt != NULL) return NULL;     /* No options recognized */
 427
 428 while ((c = *t++) != 0)
 429   if (Ustrchr("\n\t\r\b\'\"\\", c) != NULL) count++;
 430
 431 if (count == 0) return s;
 432 t = quoted = store_get(Ustrlen(s) + count + 1, is_tainted(s));
 433
 434 while ((c = *s++) != 0)
 435   {
 436   if (Ustrchr("\n\t\r\b\'\"\\", c) != NULL)
 437     {
 438     *t++ = '\\';
 439     switch(c)
 440       {
 441       case '\n': *t++ = 'n';
 442       break;
 443       case '\t': *t++ = 't';
 444       break;
 445       case '\r': *t++ = 'r';
 446       break;
 447       case '\b': *t++ = 'b';
 448       break;
 449       default:   *t++ = c;
 450       break;
 451       }
 452     }
 453   else *t++ = c;
 454   }
 455
 456 *t = 0;
 457 return quoted;
 458 }
 459
 460
 461 /*************************************************
 462 *         Version reporting entry point          *
 463 *************************************************/
 464
 465 /* See local README for interface description. */
 466
 467 #include "../version.h"
 468
 469 void
 470 mysql_version_report(FILE *f)
 471 {
 472 fprintf(f, "Library version: MySQL: Compile: %lu %s [%s]\n"
 473            "                        Runtime: %lu %s\n",
 474         (long)EXIM_MxSQL_VERSION_ID, EXIM_MxSQL_VERSION_STR, EXIM_MxSQL_BASE_STR,
 475         mysql_get_client_version(), mysql_get_client_info());
 476 #ifdef DYNLOOKUP
 477 fprintf(f, "                        Exim version %s\n", EXIM_VERSION_STR);
 478 #endif
 479 }
 480
 481 /* These are the lookup_info blocks for this driver */
 482
 483 static lookup_info mysql_lookup_info = {
 484   .name = US"mysql",                    /* lookup name */
 485   .type = lookup_querystyle,            /* query-style lookup */
 486   .open = mysql_open,                   /* open function */
 487   .check = NULL,                        /* no check function */
 488   .find = mysql_find,                   /* find function */
 489   .close = NULL,                        /* no close function */
 490   .tidy = mysql_tidy,                   /* tidy function */
 491   .quote = mysql_quote,                 /* quoting function */
 492   .version_report = mysql_version_report           /* version reporting */
 493 };
 494
 495 #ifdef DYNLOOKUP
 496 #define mysql_lookup_module_info _lookup_module_info
 497 #endif
 498
 499 static lookup_info *_lookup_list[] = { &mysql_lookup_info };
 500 lookup_module_info mysql_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
 501
 502 /* End of lookups/mysql.c */