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