src/src/lookups/pgsql.c

   1 /* $Cambridge: exim/src/src/lookups/pgsql.c,v 1.2 2005/01/04 10:00:44 ph10 Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Copyright (c) University of Cambridge 1995 - 2005 */
   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 #include "pgsql.h"       /* The local header */
  17
  18 /* We can't just compile this code and allow the library mechanism to omit the
  19 functions if they are not wanted, because we need to have the PGSQL header
  20 available for compiling. Therefore, compile these functions only if
  21 LOOKUP_PGSQL is defined. However, some compilers don't like compiling empty
  22 modules, so keep them happy with a dummy when skipping the rest. Make it
  23 reference itself to stop picky compilers complaining that it is unused, and put
  24 in a dummy argument to stop even pickier compilers complaining about infinite
  25 loops. */
  26
  27 #ifndef LOOKUP_PGSQL
  28 static void dummy(int x) { dummy(x-1); }
  29 #else
  30
  31
  32 #include <libpq-fe.h>       /* The system header */
  33
  34 /* Structure and anchor for caching connections. */
  35
  36 typedef struct pgsql_connection {
  37   struct pgsql_connection *next;
  38   uschar *server;
  39   PGconn *handle;
  40 } pgsql_connection;
  41
  42 static pgsql_connection *pgsql_connections = NULL;
  43
  44
  45
  46 /*************************************************
  47 *              Open entry point                  *
  48 *************************************************/
  49
  50 /* See local README for interface description. */
  51
  52 void *
  53 pgsql_open(uschar *filename, uschar **errmsg)
  54 {
  55 return (void *)(1);    /* Just return something non-null */
  56 }
  57
  58
  59
  60 /*************************************************
  61 *               Tidy entry point                 *
  62 *************************************************/
  63
  64 /* See local README for interface description. */
  65
  66 void
  67 pgsql_tidy(void)
  68 {
  69 pgsql_connection *cn;
  70 while ((cn = pgsql_connections) != NULL)
  71   {
  72   pgsql_connections = cn->next;
  73   DEBUG(D_lookup) debug_printf("close PGSQL connection: %s\n", cn->server);
  74   PQfinish(cn->handle);
  75   }
  76 }
  77
  78
  79
  80 /*************************************************
  81 *        Internal search function                *
  82 *************************************************/
  83
  84 /* This function is called from the find entry point to do the search for a
  85 single server. The server string is of the form "server/dbname/user/password".
  86
  87 PostgreSQL supports connections through Unix domain sockets. This is usually
  88 faster and costs less cpu time than a TCP/IP connection. However it can only be
  89 used if the mail server runs on the same machine as the database server. A
  90 configuration line for PostgreSQL via Unix domain sockets looks like this:
  91
  92 hide pgsql_servers = (/tmp/.s.PGSQL.5432)/db/user/password[:<nextserver>]
  93
  94 We enclose the path name in parentheses so that its slashes aren't visually
  95 confused with the delimeters for the other pgsql_server settings.
  96
  97 For TCP/IP connections, the server is a host name and optional port (with a
  98 colon separator).
  99
 100 NOTE:
 101  1) All three '/' must be present.
 102  2) If host is omitted the local unix socket is used.
 103
 104 Arguments:
 105   query        the query string
 106   server       the server string; this is in dynamic memory and can be updated
 107   resultptr    where to store the result
 108   errmsg       where to point an error message
 109   defer_break  TRUE if no more servers are to be tried after DEFER
 110   do_cache     set FALSE if data is changed
 111
 112 Returns:       OK, FAIL, or DEFER
 113 */
 114
 115 static int
 116 perform_pgsql_search(uschar *query, uschar *server, uschar **resultptr,
 117   uschar **errmsg, BOOL *defer_break, BOOL *do_cache)
 118 {
 119 PGconn *pg_conn = NULL;
 120 PGresult *pg_result = NULL;
 121
 122 int i;
 123 int ssize = 0;
 124 int offset = 0;
 125 int yield = DEFER;
 126 unsigned int num_fields, num_tuples;
 127 uschar *result = NULL;
 128 pgsql_connection *cn;
 129 uschar *server_copy = NULL;
 130 uschar *sdata[3];
 131
 132 /* Disaggregate the parameters from the server argument. The order is host or
 133 path, database, user, password. We can write to the string, since it is in a
 134 nextinlist temporary buffer. The copy of the string that is used for caching
 135 has the password removed. This copy is also used for debugging output. */
 136
 137 for (i = 2; i >= 0; i--)
 138   {
 139   uschar *pp = Ustrrchr(server, '/');
 140   if (pp == NULL)
 141     {
 142     *errmsg = string_sprintf("incomplete pgSQL server data: %s",
 143       (i == 2)? server : server_copy);
 144     *defer_break = TRUE;
 145     return DEFER;
 146     }
 147   *pp++ = 0;
 148   sdata[i] = pp;
 149   if (i == 2) server_copy = string_copy(server);  /* sans password */
 150   }
 151
 152 /* The total server string has now been truncated so that what is left at the
 153 start is the identification of the server (host or path). See if we have a
 154 cached connection to the server. */
 155
 156 for (cn = pgsql_connections; cn != NULL; cn = cn->next)
 157   {
 158   if (Ustrcmp(cn->server, server_copy) == 0)
 159     {
 160     pg_conn = cn->handle;
 161     break;
 162     }
 163   }
 164
 165 /* If there is no cached connection, we must set one up. */
 166
 167 if (cn == NULL)
 168   {
 169   uschar *port = US"";
 170
 171   /* For a Unix domain socket connection, the path is in parentheses */
 172
 173   if (*server == '(')
 174     {
 175     uschar *last_slash, *last_dot, *p;
 176
 177     p = ++server;
 178     while (*p != 0 && *p != ')') p++;
 179     *p = 0;
 180
 181     last_slash = Ustrrchr(server, '/');
 182     last_dot = Ustrrchr(server, '.');
 183
 184     DEBUG(D_lookup) debug_printf("PGSQL new connection: socket=%s "
 185       "database=%s user=%s\n", server, sdata[0], sdata[1]);
 186
 187     /* A valid socket name looks like this: /var/run/postgresql/.s.PGSQL.5432
 188     We have to call PQsetdbLogin with '/var/run/postgresql' as the hostname
 189     argument and put '5432' into the port variable. */
 190
 191     if (last_slash == NULL || last_dot == NULL)
 192       {
 193       *errmsg = string_sprintf("PGSQL invalid filename for socket: %s",
 194         server);
 195       *defer_break = TRUE;
 196       return DEFER;
 197       }
 198
 199     /* Terminate the path name and set up the port: we'll have something like
 200     server = "/var/run/postgresql" and port = "5432". */
 201
 202     *last_slash = 0;
 203     port = last_dot + 1;
 204     }
 205
 206   /* Host connection; sort out the port */
 207
 208   else
 209     {
 210     uschar *p;
 211     if ((p = Ustrchr(server, ':')) != NULL)
 212       {
 213       *p++ = 0;
 214       port = p;
 215       }
 216
 217     if (Ustrchr(server, '/') != NULL)
 218       {
 219       *errmsg = string_sprintf("unexpected slash in pgSQL server hostname: %s",
 220         server);
 221       *defer_break = TRUE;
 222       return DEFER;
 223       }
 224
 225     DEBUG(D_lookup) debug_printf("PGSQL new connection: host=%s port=%s "
 226       "database=%s user=%s\n", server, port, sdata[0], sdata[1]);
 227     }
 228
 229   /* If the database is the empty string, set it NULL - the query must then
 230   define it. */
 231
 232   if (sdata[0][0] == 0) sdata[0] = NULL;
 233
 234   /* Get store for a new handle, initialize it, and connect to the server */
 235
 236   pg_conn=PQsetdbLogin(
 237     /*  host      port  options tty   database       user       passwd */
 238     CS server, CS port,  NULL, NULL, CS sdata[0], CS sdata[1], CS sdata[2]);
 239
 240   if(PQstatus(pg_conn) == CONNECTION_BAD)
 241     {
 242     store_reset(server_copy);
 243     *errmsg = string_sprintf("PGSQL connection failed: %s",
 244       PQerrorMessage(pg_conn));
 245     PQfinish(pg_conn);
 246     *defer_break = FALSE;
 247     goto PGSQL_EXIT;
 248     }
 249
 250   /* Add the connection to the cache */
 251
 252   cn = store_get(sizeof(pgsql_connection));
 253   cn->server = server_copy;
 254   cn->handle = pg_conn;
 255   cn->next = pgsql_connections;
 256   pgsql_connections = cn;
 257   }
 258
 259 /* Else use a previously cached connection */
 260
 261 else
 262   {
 263   DEBUG(D_lookup) debug_printf("PGSQL using cached connection for %s\n",
 264     server_copy);
 265   }
 266
 267 /* Run the query */
 268
 269   pg_result = PQexec(pg_conn, CS query);
 270   switch(PQresultStatus(pg_result))
 271     {
 272     case PGRES_EMPTY_QUERY:
 273     case PGRES_COMMAND_OK:
 274     /* The command was successful but did not return any data since it was
 275      * not SELECT but either an INSERT, UPDATE or DELETE statement. Tell the
 276      * high level code to not cache this query, and clean the current cache for
 277      * this handle by setting *do_cache FALSE. */
 278     result = string_copy(US PQcmdTuples(pg_result));
 279     offset = Ustrlen(result);
 280     *do_cache = FALSE;
 281     DEBUG(D_lookup) debug_printf("PGSQL: command does not return any data "
 282       "but was successful. Rows affected: %s\n", result);
 283
 284     case PGRES_TUPLES_OK:
 285     break;
 286
 287     default:
 288     *errmsg = string_sprintf("PGSQL: query failed: %s\n",
 289                              PQresultErrorMessage(pg_result));
 290     *defer_break = FALSE;
 291     goto PGSQL_EXIT;
 292     }
 293
 294 /* Result is in pg_result. Find the number of fields returned. If this is one,
 295 we don't add field names to the data. Otherwise we do. If the query did not
 296 return anything we skip the for loop; this also applies to the case
 297 PGRES_COMMAND_OK. */
 298
 299 num_fields = PQnfields(pg_result);
 300 num_tuples = PQntuples(pg_result);
 301
 302 /* Get the fields and construct the result string. If there is more than one
 303 row, we insert '\n' between them. */
 304
 305 for (i = 0; i < num_tuples; i++)
 306   {
 307   if (result != NULL)
 308     result = string_cat(result, &ssize, &offset, US"\n", 1);
 309
 310    if (num_fields == 1)
 311     {
 312     result = string_cat(result, &ssize, &offset,
 313       US PQgetvalue(pg_result, i, 0), PQgetlength(pg_result, i, 0));
 314     }
 315
 316    else
 317     {
 318     int j;
 319     for (j = 0; j < num_fields; j++)
 320       {
 321       uschar *tmp = US PQgetvalue(pg_result, i, j);
 322       result = lf_quote(US PQfname(pg_result, j), tmp, Ustrlen(tmp), result,
 323         &ssize, &offset);
 324       }
 325     }
 326   }
 327
 328 /* If result is NULL then no data has been found and so we return FAIL.
 329 Otherwise, we must terminate the string which has been built; string_cat()
 330 always leaves enough room for a terminating zero. */
 331
 332 if (result == NULL)
 333   {
 334   yield = FAIL;
 335   *errmsg = US"PGSQL: no data found";
 336   }
 337 else
 338   {
 339   result[offset] = 0;
 340   store_reset(result + offset + 1);
 341   }
 342
 343 /* Get here by goto from various error checks. */
 344
 345 PGSQL_EXIT:
 346
 347 /* Free store for any result that was got; don't close the connection, as
 348 it is cached. */
 349
 350 if (pg_result != NULL) PQclear(pg_result);
 351
 352 /* Non-NULL result indicates a sucessful result */
 353
 354 if (result != NULL)
 355   {
 356   *resultptr = result;
 357   return OK;
 358   }
 359 else
 360   {
 361   DEBUG(D_lookup) debug_printf("%s\n", *errmsg);
 362   return yield;      /* FAIL or DEFER */
 363   }
 364 }
 365
 366
 367
 368
 369 /*************************************************
 370 *               Find entry point                 *
 371 *************************************************/
 372
 373 /* See local README for interface description. The handle and filename
 374 arguments are not used. Loop through a list of servers while the query is
 375 deferred with a retryable error. */
 376
 377 int
 378 pgsql_find(void *handle, uschar *filename, uschar *query, int length,
 379   uschar **result, uschar **errmsg, BOOL *do_cache)
 380 {
 381 int sep = 0;
 382 uschar *server;
 383 uschar *list = pgsql_servers;
 384 uschar buffer[512];
 385
 386 DEBUG(D_lookup) debug_printf("PGSQL query: %s\n", query);
 387
 388 while ((server = string_nextinlist(&list, &sep, buffer, sizeof(buffer)))
 389         != NULL)
 390   {
 391   BOOL defer_break;
 392   int rc = perform_pgsql_search(query, server, result, errmsg, &defer_break,
 393     do_cache);
 394   if (rc != DEFER || defer_break) return rc;
 395   }
 396
 397 if (pgsql_servers == NULL)
 398   *errmsg = US"no PGSQL servers defined (pgsql_servers option)";
 399
 400 return DEFER;
 401 }
 402
 403
 404
 405 /*************************************************
 406 *               Quote entry point                *
 407 *************************************************/
 408
 409 /* The characters that always need to be quoted (with backslash) are newline,
 410 tab, carriage return, backspace, backslash itself, and the quote characters.
 411 Percent and underscore are only special in contexts where they can be wild
 412 cards, and this isn't usually the case for data inserted from messages, since
 413 that isn't likely to be treated as a pattern of any kind. However, pgsql seems
 414 to allow escaping "on spec". If you use something like "where id="ab\%cd" it
 415 does treat the string as "ab%cd". So we can safely quote percent and
 416 underscore. [This is different to MySQL, where you can't do this.]
 417
 418 Arguments:
 419   s          the string to be quoted
 420   opt        additional option text or NULL if none
 421
 422 Returns:     the processed string or NULL for a bad option
 423 */
 424
 425 uschar *
 426 pgsql_quote(uschar *s, uschar *opt)
 427 {
 428 register int c;
 429 int count = 0;
 430 uschar *t = s;
 431 uschar *quoted;
 432
 433 if (opt != NULL) return NULL;     /* No options recognized */
 434
 435 while ((c = *t++) != 0)
 436   if (Ustrchr("\n\t\r\b\'\"\\%_", c) != NULL) count++;
 437
 438 if (count == 0) return s;
 439 t = quoted = store_get(Ustrlen(s) + count + 1);
 440
 441 while ((c = *s++) != 0)
 442   {
 443   if (Ustrchr("\n\t\r\b\'\"\\%_", c) != NULL)
 444     {
 445     *t++ = '\\';
 446     switch(c)
 447       {
 448       case '\n': *t++ = 'n';
 449       break;
 450       case '\t': *t++ = 't';
 451       break;
 452       case '\r': *t++ = 'r';
 453       break;
 454       case '\b': *t++ = 'b';
 455       break;
 456       default:   *t++ = c;
 457       break;
 458       }
 459     }
 460   else *t++ = c;
 461   }
 462
 463 *t = 0;
 464 return quoted;
 465 }
 466
 467 #endif  /* PGSQL_LOOKUP */
 468
 469 /* End of lookups/pgsql.c */