src/src/lookups/pgsql.c

   1 /* $Cambridge: exim/src/src/lookups/pgsql.c,v 1.11 2009/11/16 19:50:38 nm4 Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Copyright (c) University of Cambridge 1995 - 2009 */
   8 /* See the file NOTICE for conditions of use and distribution. */
   9
  10 /* Thanks to Petr Cech for contributing the original code for these
  11 functions. Thanks to Joachim Wieland for the initial patch for the Unix domain
  12 socket extension. */
  13
  14 #include "../exim.h"
  15 #include "lf_functions.h"
  16
  17 #include <libpq-fe.h>       /* The system header */
  18
  19 /* Structure and anchor for caching connections. */
  20
  21 typedef struct pgsql_connection {
  22   struct pgsql_connection *next;
  23   uschar *server;
  24   PGconn *handle;
  25 } pgsql_connection;
  26
  27 static pgsql_connection *pgsql_connections = NULL;
  28
  29
  30
  31 /*************************************************
  32 *              Open entry point                  *
  33 *************************************************/
  34
  35 /* See local README for interface description. */
  36
  37 static void *
  38 pgsql_open(uschar *filename, uschar **errmsg)
  39 {
  40 return (void *)(1);    /* Just return something non-null */
  41 }
  42
  43
  44
  45 /*************************************************
  46 *               Tidy entry point                 *
  47 *************************************************/
  48
  49 /* See local README for interface description. */
  50
  51 static void
  52 pgsql_tidy(void)
  53 {
  54 pgsql_connection *cn;
  55 while ((cn = pgsql_connections) != NULL)
  56   {
  57   pgsql_connections = cn->next;
  58   DEBUG(D_lookup) debug_printf("close PGSQL connection: %s\n", cn->server);
  59   PQfinish(cn->handle);
  60   }
  61 }
  62
  63
  64 /*************************************************
  65 *       Notice processor function for pgsql      *
  66 *************************************************/
  67
  68 /* This function is passed to pgsql below, and called for any PostgreSQL
  69 "notices". By default they are written to stderr, which is undesirable.
  70
  71 Arguments:
  72   arg        an opaque user cookie (not used)
  73   message    the notice
  74
  75 Returns:     nothing
  76 */
  77
  78 static void
  79 notice_processor(void *arg, const char *message)
  80 {
  81 arg = arg;   /* Keep compiler happy */
  82 DEBUG(D_lookup) debug_printf("PGSQL: %s\n", message);
  83 }
  84
  85
  86
  87 /*************************************************
  88 *        Internal search function                *
  89 *************************************************/
  90
  91 /* This function is called from the find entry point to do the search for a
  92 single server. The server string is of the form "server/dbname/user/password".
  93
  94 PostgreSQL supports connections through Unix domain sockets. This is usually
  95 faster and costs less cpu time than a TCP/IP connection. However it can only be
  96 used if the mail server runs on the same machine as the database server. A
  97 configuration line for PostgreSQL via Unix domain sockets looks like this:
  98
  99 hide pgsql_servers = (/tmp/.s.PGSQL.5432)/db/user/password[:<nextserver>]
 100
 101 We enclose the path name in parentheses so that its slashes aren't visually
 102 confused with the delimeters for the other pgsql_server settings.
 103
 104 For TCP/IP connections, the server is a host name and optional port (with a
 105 colon separator).
 106
 107 NOTE:
 108  1) All three '/' must be present.
 109  2) If host is omitted the local unix socket is used.
 110
 111 Arguments:
 112   query        the query string
 113   server       the server string; this is in dynamic memory and can be updated
 114   resultptr    where to store the result
 115   errmsg       where to point an error message
 116   defer_break  set TRUE if no more servers are to be tried after DEFER
 117   do_cache     set FALSE if data is changed
 118
 119 Returns:       OK, FAIL, or DEFER
 120 */
 121
 122 static int
 123 perform_pgsql_search(uschar *query, uschar *server, uschar **resultptr,
 124   uschar **errmsg, BOOL *defer_break, BOOL *do_cache)
 125 {
 126 PGconn *pg_conn = NULL;
 127 PGresult *pg_result = NULL;
 128
 129 int i;
 130 int ssize = 0;
 131 int offset = 0;
 132 int yield = DEFER;
 133 unsigned int num_fields, num_tuples;
 134 uschar *result = NULL;
 135 pgsql_connection *cn;
 136 uschar *server_copy = NULL;
 137 uschar *sdata[3];
 138
 139 /* Disaggregate the parameters from the server argument. The order is host or
 140 path, database, user, password. We can write to the string, since it is in a
 141 nextinlist temporary buffer. The copy of the string that is used for caching
 142 has the password removed. This copy is also used for debugging output. */
 143
 144 for (i = 2; i >= 0; i--)
 145   {
 146   uschar *pp = Ustrrchr(server, '/');
 147   if (pp == NULL)
 148     {
 149     *errmsg = string_sprintf("incomplete pgSQL server data: %s",
 150       (i == 2)? server : server_copy);
 151     *defer_break = TRUE;
 152     return DEFER;
 153     }
 154   *pp++ = 0;
 155   sdata[i] = pp;
 156   if (i == 2) server_copy = string_copy(server);  /* sans password */
 157   }
 158
 159 /* The total server string has now been truncated so that what is left at the
 160 start is the identification of the server (host or path). See if we have a
 161 cached connection to the server. */
 162
 163 for (cn = pgsql_connections; cn != NULL; cn = cn->next)
 164   {
 165   if (Ustrcmp(cn->server, server_copy) == 0)
 166     {
 167     pg_conn = cn->handle;
 168     break;
 169     }
 170   }
 171
 172 /* If there is no cached connection, we must set one up. */
 173
 174 if (cn == NULL)
 175   {
 176   uschar *port = US"";
 177
 178   /* For a Unix domain socket connection, the path is in parentheses */
 179
 180   if (*server == '(')
 181     {
 182     uschar *last_slash, *last_dot, *p;
 183
 184     p = ++server;
 185     while (*p != 0 && *p != ')') p++;
 186     *p = 0;
 187
 188     last_slash = Ustrrchr(server, '/');
 189     last_dot = Ustrrchr(server, '.');
 190
 191     DEBUG(D_lookup) debug_printf("PGSQL new connection: socket=%s "
 192       "database=%s user=%s\n", server, sdata[0], sdata[1]);
 193
 194     /* A valid socket name looks like this: /var/run/postgresql/.s.PGSQL.5432
 195     We have to call PQsetdbLogin with '/var/run/postgresql' as the hostname
 196     argument and put '5432' into the port variable. */
 197
 198     if (last_slash == NULL || last_dot == NULL)
 199       {
 200       *errmsg = string_sprintf("PGSQL invalid filename for socket: %s",
 201         server);
 202       *defer_break = TRUE;
 203       return DEFER;
 204       }
 205
 206     /* Terminate the path name and set up the port: we'll have something like
 207     server = "/var/run/postgresql" and port = "5432". */
 208
 209     *last_slash = 0;
 210     port = last_dot + 1;
 211     }
 212
 213   /* Host connection; sort out the port */
 214
 215   else
 216     {
 217     uschar *p;
 218     if ((p = Ustrchr(server, ':')) != NULL)
 219       {
 220       *p++ = 0;
 221       port = p;
 222       }
 223
 224     if (Ustrchr(server, '/') != NULL)
 225       {
 226       *errmsg = string_sprintf("unexpected slash in pgSQL server hostname: %s",
 227         server);
 228       *defer_break = TRUE;
 229       return DEFER;
 230       }
 231
 232     DEBUG(D_lookup) debug_printf("PGSQL new connection: host=%s port=%s "
 233       "database=%s user=%s\n", server, port, sdata[0], sdata[1]);
 234     }
 235
 236   /* If the database is the empty string, set it NULL - the query must then
 237   define it. */
 238
 239   if (sdata[0][0] == 0) sdata[0] = NULL;
 240
 241   /* Get store for a new handle, initialize it, and connect to the server */
 242
 243   pg_conn=PQsetdbLogin(
 244     /*  host      port  options tty   database       user       passwd */
 245     CS server, CS port,  NULL, NULL, CS sdata[0], CS sdata[1], CS sdata[2]);
 246
 247   if(PQstatus(pg_conn) == CONNECTION_BAD)
 248     {
 249     store_reset(server_copy);
 250     *errmsg = string_sprintf("PGSQL connection failed: %s",
 251       PQerrorMessage(pg_conn));
 252     PQfinish(pg_conn);
 253     goto PGSQL_EXIT;
 254     }
 255
 256   /* Set the client encoding to SQL_ASCII, which means that the server will
 257   not try to interpret the query as being in any fancy encoding such as UTF-8
 258   or other multibyte code that might cause problems with escaping. */
 259
 260   PQsetClientEncoding(pg_conn, "SQL_ASCII");
 261
 262   /* Set the notice processor to prevent notices from being written to stderr
 263   (which is what the default does). Our function (above) just produces debug
 264   output. */
 265
 266   PQsetNoticeProcessor(pg_conn, notice_processor, NULL);
 267
 268   /* Add the connection to the cache */
 269
 270   cn = store_get(sizeof(pgsql_connection));
 271   cn->server = server_copy;
 272   cn->handle = pg_conn;
 273   cn->next = pgsql_connections;
 274   pgsql_connections = cn;
 275   }
 276
 277 /* Else use a previously cached connection */
 278
 279 else
 280   {
 281   DEBUG(D_lookup) debug_printf("PGSQL using cached connection for %s\n",
 282     server_copy);
 283   }
 284
 285 /* Run the query */
 286
 287   pg_result = PQexec(pg_conn, CS query);
 288   switch(PQresultStatus(pg_result))
 289     {
 290     case PGRES_EMPTY_QUERY:
 291     case PGRES_COMMAND_OK:
 292     /* The command was successful but did not return any data since it was
 293      * not SELECT but either an INSERT, UPDATE or DELETE statement. Tell the
 294      * high level code to not cache this query, and clean the current cache for
 295      * this handle by setting *do_cache FALSE. */
 296     result = string_copy(US PQcmdTuples(pg_result));
 297     offset = Ustrlen(result);
 298     *do_cache = FALSE;
 299     DEBUG(D_lookup) debug_printf("PGSQL: command does not return any data "
 300       "but was successful. Rows affected: %s\n", result);
 301
 302     case PGRES_TUPLES_OK:
 303     break;
 304
 305     default:
 306     /* This was the original code:
 307     *errmsg = string_sprintf("PGSQL: query failed: %s\n",
 308                              PQresultErrorMessage(pg_result));
 309     This was suggested by a user:
 310     */
 311
 312     *errmsg = string_sprintf("PGSQL: query failed: %s (%s) (%s)\n",
 313                              PQresultErrorMessage(pg_result),
 314                              PQresStatus(PQresultStatus(pg_result)), query);
 315     goto PGSQL_EXIT;
 316     }
 317
 318 /* Result is in pg_result. Find the number of fields returned. If this is one,
 319 we don't add field names to the data. Otherwise we do. If the query did not
 320 return anything we skip the for loop; this also applies to the case
 321 PGRES_COMMAND_OK. */
 322
 323 num_fields = PQnfields(pg_result);
 324 num_tuples = PQntuples(pg_result);
 325
 326 /* Get the fields and construct the result string. If there is more than one
 327 row, we insert '\n' between them. */
 328
 329 for (i = 0; i < num_tuples; i++)
 330   {
 331   if (result != NULL)
 332     result = string_cat(result, &ssize, &offset, US"\n", 1);
 333
 334    if (num_fields == 1)
 335     {
 336     result = string_cat(result, &ssize, &offset,
 337       US PQgetvalue(pg_result, i, 0), PQgetlength(pg_result, i, 0));
 338     }
 339
 340    else
 341     {
 342     int j;
 343     for (j = 0; j < num_fields; j++)
 344       {
 345       uschar *tmp = US PQgetvalue(pg_result, i, j);
 346       result = lf_quote(US PQfname(pg_result, j), tmp, Ustrlen(tmp), result,
 347         &ssize, &offset);
 348       }
 349     }
 350   }
 351
 352 /* If result is NULL then no data has been found and so we return FAIL.
 353 Otherwise, we must terminate the string which has been built; string_cat()
 354 always leaves enough room for a terminating zero. */
 355
 356 if (result == NULL)
 357   {
 358   yield = FAIL;
 359   *errmsg = US"PGSQL: no data found";
 360   }
 361 else
 362   {
 363   result[offset] = 0;
 364   store_reset(result + offset + 1);
 365   }
 366
 367 /* Get here by goto from various error checks. */
 368
 369 PGSQL_EXIT:
 370
 371 /* Free store for any result that was got; don't close the connection, as
 372 it is cached. */
 373
 374 if (pg_result != NULL) PQclear(pg_result);
 375
 376 /* Non-NULL result indicates a sucessful result */
 377
 378 if (result != NULL)
 379   {
 380   *resultptr = result;
 381   return OK;
 382   }
 383 else
 384   {
 385   DEBUG(D_lookup) debug_printf("%s\n", *errmsg);
 386   return yield;      /* FAIL or DEFER */
 387   }
 388 }
 389
 390
 391
 392
 393 /*************************************************
 394 *               Find entry point                 *
 395 *************************************************/
 396
 397 /* See local README for interface description. The handle and filename
 398 arguments are not used. The code to loop through a list of servers while the
 399 query is deferred with a retryable error is now in a separate function that is
 400 shared with other SQL lookups. */
 401
 402 static int
 403 pgsql_find(void *handle, uschar *filename, uschar *query, int length,
 404   uschar **result, uschar **errmsg, BOOL *do_cache)
 405 {
 406 return lf_sqlperform(US"PostgreSQL", US"pgsql_servers", pgsql_servers, query,
 407   result, errmsg, do_cache, perform_pgsql_search);
 408 }
 409
 410
 411
 412 /*************************************************
 413 *               Quote entry point                *
 414 *************************************************/
 415
 416 /* The characters that always need to be quoted (with backslash) are newline,
 417 tab, carriage return, backspace, backslash itself, and the quote characters.
 418 Percent and underscore are only special in contexts where they can be wild
 419 cards, and this isn't usually the case for data inserted from messages, since
 420 that isn't likely to be treated as a pattern of any kind. However, pgsql seems
 421 to allow escaping "on spec". If you use something like "where id="ab\%cd" it
 422 does treat the string as "ab%cd". So we can safely quote percent and
 423 underscore. [This is different to MySQL, where you can't do this.]
 424
 425 The original code quoted single quotes as \' which is documented as valid in
 426 the O'Reilly book "Practical PostgreSQL" (first edition) as an alternative to
 427 the SQL standard '' way of representing a single quote as data. However, in
 428 June 2006 there was some security issue with using \' and so this has been
 429 changed.
 430
 431 [Note: There is a function called PQescapeStringConn() that quotes strings.
 432 This cannot be used because it needs a PGconn argument (the connection handle).
 433 Why, I don't know. Seems odd for just string escaping...]
 434
 435 Arguments:
 436   s          the string to be quoted
 437   opt        additional option text or NULL if none
 438
 439 Returns:     the processed string or NULL for a bad option
 440 */
 441
 442 static uschar *
 443 pgsql_quote(uschar *s, uschar *opt)
 444 {
 445 register int c;
 446 int count = 0;
 447 uschar *t = s;
 448 uschar *quoted;
 449
 450 if (opt != NULL) return NULL;     /* No options recognized */
 451
 452 while ((c = *t++) != 0)
 453   if (Ustrchr("\n\t\r\b\'\"\\%_", c) != NULL) count++;
 454
 455 if (count == 0) return s;
 456 t = quoted = store_get(Ustrlen(s) + count + 1);
 457
 458 while ((c = *s++) != 0)
 459   {
 460   if (c == '\'')
 461     {
 462     *t++ = '\'';
 463     *t++ = '\'';
 464     }
 465   else if (Ustrchr("\n\t\r\b\"\\%_", c) != NULL)
 466     {
 467     *t++ = '\\';
 468     switch(c)
 469       {
 470       case '\n': *t++ = 'n';
 471       break;
 472       case '\t': *t++ = 't';
 473       break;
 474       case '\r': *t++ = 'r';
 475       break;
 476       case '\b': *t++ = 'b';
 477       break;
 478       default:   *t++ = c;
 479       break;
 480       }
 481     }
 482   else *t++ = c;
 483   }
 484
 485 *t = 0;
 486 return quoted;
 487 }
 488
 489
 490 /*************************************************
 491 *         Version reporting entry point          *
 492 *************************************************/
 493
 494 /* See local README for interface description. */
 495
 496 #include "../version.h"
 497
 498 void
 499 pgsql_version_report(FILE *f)
 500 {
 501 #ifdef DYNLOOKUP
 502 fprintf(f, "Library version: PostgreSQL: Exim version %s\n", EXIM_VERSION_STR);
 503 #endif
 504
 505 /* Version reporting: there appears to be no available information about
 506 the client library in libpq-fe.h; once you have a connection object, you
 507 can access the server version and the chosen protocol version, but those
 508 aren't really what we want.  It might make sense to debug_printf those
 509 when the connection is established though? */
 510 }
 511
 512
 513 static lookup_info _lookup_info = {
 514   US"pgsql",                     /* lookup name */
 515   lookup_querystyle,             /* query-style lookup */
 516   pgsql_open,                    /* open function */
 517   NULL,                          /* no check function */
 518   pgsql_find,                    /* find function */
 519   NULL,                          /* no close function */
 520   pgsql_tidy,                    /* tidy function */
 521   pgsql_quote,                   /* quoting function */
 522   pgsql_version_report           /* version reporting */
 523 };
 524
 525 #ifdef DYNLOOKUP
 526 #define pgsql_lookup_module_info _lookup_module_info
 527 #endif
 528
 529 static lookup_info *_lookup_list[] = { &_lookup_info };
 530 lookup_module_info pgsql_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
 531
 532 /* End of lookups/pgsql.c */