Line data Source code
1 : /*
2 : * dblink.c
3 : *
4 : * Functions returning results from a remote database
5 : *
6 : * Joe Conway <mail@joeconway.com>
7 : * And contributors:
8 : * Darko Prenosil <Darko.Prenosil@finteh.hr>
9 : * Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
10 : *
11 : * contrib/dblink/dblink.c
12 : * Copyright (c) 2001-2024, PostgreSQL Global Development Group
13 : * ALL RIGHTS RESERVED;
14 : *
15 : * Permission to use, copy, modify, and distribute this software and its
16 : * documentation for any purpose, without fee, and without a written agreement
17 : * is hereby granted, provided that the above copyright notice and this
18 : * paragraph and the following two paragraphs appear in all copies.
19 : *
20 : * IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
21 : * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
22 : * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
23 : * DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
24 : * POSSIBILITY OF SUCH DAMAGE.
25 : *
26 : * THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
27 : * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
28 : * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
29 : * ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
30 : * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
31 : *
32 : */
33 : #include "postgres.h"
34 :
35 : #include <limits.h>
36 :
37 : #include "access/htup_details.h"
38 : #include "access/relation.h"
39 : #include "access/reloptions.h"
40 : #include "access/table.h"
41 : #include "catalog/namespace.h"
42 : #include "catalog/pg_foreign_data_wrapper.h"
43 : #include "catalog/pg_foreign_server.h"
44 : #include "catalog/pg_type.h"
45 : #include "catalog/pg_user_mapping.h"
46 : #include "executor/spi.h"
47 : #include "foreign/foreign.h"
48 : #include "funcapi.h"
49 : #include "lib/stringinfo.h"
50 : #include "libpq-fe.h"
51 : #include "libpq/libpq-be.h"
52 : #include "libpq/libpq-be-fe-helpers.h"
53 : #include "mb/pg_wchar.h"
54 : #include "miscadmin.h"
55 : #include "parser/scansup.h"
56 : #include "utils/acl.h"
57 : #include "utils/builtins.h"
58 : #include "utils/fmgroids.h"
59 : #include "utils/guc.h"
60 : #include "utils/lsyscache.h"
61 : #include "utils/memutils.h"
62 : #include "utils/rel.h"
63 : #include "utils/varlena.h"
64 : #include "utils/wait_event.h"
65 :
66 6 : PG_MODULE_MAGIC;
67 :
68 : typedef struct remoteConn
69 : {
70 : PGconn *conn; /* Hold the remote connection */
71 : int openCursorCount; /* The number of open cursors */
72 : bool newXactForCursor; /* Opened a transaction for a cursor */
73 : } remoteConn;
74 :
75 : typedef struct storeInfo
76 : {
77 : FunctionCallInfo fcinfo;
78 : Tuplestorestate *tuplestore;
79 : AttInMetadata *attinmeta;
80 : MemoryContext tmpcontext;
81 : char **cstrs;
82 : /* temp storage for results to avoid leaks on exception */
83 : PGresult *last_res;
84 : PGresult *cur_res;
85 : } storeInfo;
86 :
87 : /*
88 : * Internal declarations
89 : */
90 : static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async);
91 : static void prepTuplestoreResult(FunctionCallInfo fcinfo);
92 : static void materializeResult(FunctionCallInfo fcinfo, PGconn *conn,
93 : PGresult *res);
94 : static void materializeQueryResult(FunctionCallInfo fcinfo,
95 : PGconn *conn,
96 : const char *conname,
97 : const char *sql,
98 : bool fail);
99 : static PGresult *storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql);
100 : static void storeRow(volatile storeInfo *sinfo, PGresult *res, bool first);
101 : static remoteConn *getConnectionByName(const char *name);
102 : static HTAB *createConnHash(void);
103 : static void createNewConnection(const char *name, remoteConn *rconn);
104 : static void deleteConnection(const char *name);
105 : static char **get_pkey_attnames(Relation rel, int16 *indnkeyatts);
106 : static char **get_text_array_contents(ArrayType *array, int *numitems);
107 : static char *get_sql_insert(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals);
108 : static char *get_sql_delete(Relation rel, int *pkattnums, int pknumatts, char **tgt_pkattvals);
109 : static char *get_sql_update(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals);
110 : static char *quote_ident_cstr(char *rawstr);
111 : static int get_attnum_pk_pos(int *pkattnums, int pknumatts, int key);
112 : static HeapTuple get_tuple_of_interest(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals);
113 : static Relation get_rel_from_relname(text *relname_text, LOCKMODE lockmode, AclMode aclmode);
114 : static char *generate_relation_name(Relation rel);
115 : static void dblink_connstr_check(const char *connstr);
116 : static bool dblink_connstr_has_pw(const char *connstr);
117 : static void dblink_security_check(PGconn *conn, remoteConn *rconn, const char *connstr);
118 : static void dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
119 : bool fail, const char *fmt,...) pg_attribute_printf(5, 6);
120 : static char *get_connect_string(const char *servername);
121 : static char *escape_param_str(const char *str);
122 : static void validate_pkattnums(Relation rel,
123 : int2vector *pkattnums_arg, int32 pknumatts_arg,
124 : int **pkattnums, int *pknumatts);
125 : static bool is_valid_dblink_option(const PQconninfoOption *options,
126 : const char *option, Oid context);
127 : static int applyRemoteGucs(PGconn *conn);
128 : static void restoreLocalGucs(int nestlevel);
129 :
130 : /* Global */
131 : static remoteConn *pconn = NULL;
132 : static HTAB *remoteConnHash = NULL;
133 :
134 : /* custom wait event values, retrieved from shared memory */
135 : static uint32 dblink_we_connect = 0;
136 : static uint32 dblink_we_get_conn = 0;
137 : static uint32 dblink_we_get_result = 0;
138 :
139 : /*
140 : * Following is list that holds multiple remote connections.
141 : * Calling convention of each dblink function changes to accept
142 : * connection name as the first parameter. The connection list is
143 : * much like ecpg e.g. a mapping between a name and a PGconn object.
144 : */
145 :
146 : typedef struct remoteConnHashEnt
147 : {
148 : char name[NAMEDATALEN];
149 : remoteConn *rconn;
150 : } remoteConnHashEnt;
151 :
152 : /* initial number of connection hashes */
153 : #define NUMCONN 16
154 :
155 : static char *
156 96 : xpstrdup(const char *in)
157 : {
158 96 : if (in == NULL)
159 72 : return NULL;
160 24 : return pstrdup(in);
161 : }
162 :
163 : static void
164 : pg_attribute_noreturn()
165 0 : dblink_res_internalerror(PGconn *conn, PGresult *res, const char *p2)
166 : {
167 0 : char *msg = pchomp(PQerrorMessage(conn));
168 :
169 0 : PQclear(res);
170 0 : elog(ERROR, "%s: %s", p2, msg);
171 : }
172 :
173 : static void
174 : pg_attribute_noreturn()
175 6 : dblink_conn_not_avail(const char *conname)
176 : {
177 6 : if (conname)
178 2 : ereport(ERROR,
179 : (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
180 : errmsg("connection \"%s\" not available", conname)));
181 : else
182 4 : ereport(ERROR,
183 : (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
184 : errmsg("connection not available")));
185 : }
186 :
187 : static void
188 66 : dblink_get_conn(char *conname_or_str,
189 : PGconn *volatile *conn_p, char **conname_p, volatile bool *freeconn_p)
190 : {
191 66 : remoteConn *rconn = getConnectionByName(conname_or_str);
192 : PGconn *conn;
193 : char *conname;
194 : bool freeconn;
195 :
196 66 : if (rconn)
197 : {
198 54 : conn = rconn->conn;
199 54 : conname = conname_or_str;
200 54 : freeconn = false;
201 : }
202 : else
203 : {
204 : const char *connstr;
205 :
206 12 : connstr = get_connect_string(conname_or_str);
207 12 : if (connstr == NULL)
208 12 : connstr = conname_or_str;
209 12 : dblink_connstr_check(connstr);
210 :
211 : /* first time, allocate or get the custom wait event */
212 12 : if (dblink_we_get_conn == 0)
213 4 : dblink_we_get_conn = WaitEventExtensionNew("DblinkGetConnect");
214 :
215 : /* OK to make connection */
216 12 : conn = libpqsrv_connect(connstr, dblink_we_get_conn);
217 :
218 12 : if (PQstatus(conn) == CONNECTION_BAD)
219 : {
220 4 : char *msg = pchomp(PQerrorMessage(conn));
221 :
222 4 : libpqsrv_disconnect(conn);
223 4 : ereport(ERROR,
224 : (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
225 : errmsg("could not establish connection"),
226 : errdetail_internal("%s", msg)));
227 : }
228 8 : dblink_security_check(conn, rconn, connstr);
229 8 : if (PQclientEncoding(conn) != GetDatabaseEncoding())
230 0 : PQsetClientEncoding(conn, GetDatabaseEncodingName());
231 8 : freeconn = true;
232 8 : conname = NULL;
233 : }
234 :
235 62 : *conn_p = conn;
236 62 : *conname_p = conname;
237 62 : *freeconn_p = freeconn;
238 62 : }
239 :
240 : static PGconn *
241 34 : dblink_get_named_conn(const char *conname)
242 : {
243 34 : remoteConn *rconn = getConnectionByName(conname);
244 :
245 34 : if (rconn)
246 34 : return rconn->conn;
247 :
248 0 : dblink_conn_not_avail(conname);
249 : return NULL; /* keep compiler quiet */
250 : }
251 :
252 : static void
253 240 : dblink_init(void)
254 : {
255 240 : if (!pconn)
256 : {
257 6 : if (dblink_we_get_result == 0)
258 6 : dblink_we_get_result = WaitEventExtensionNew("DblinkGetResult");
259 :
260 6 : pconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext, sizeof(remoteConn));
261 6 : pconn->conn = NULL;
262 6 : pconn->openCursorCount = 0;
263 6 : pconn->newXactForCursor = false;
264 : }
265 240 : }
266 :
267 : /*
268 : * Create a persistent connection to another database
269 : */
270 18 : PG_FUNCTION_INFO_V1(dblink_connect);
271 : Datum
272 32 : dblink_connect(PG_FUNCTION_ARGS)
273 : {
274 32 : char *conname_or_str = NULL;
275 32 : char *connstr = NULL;
276 32 : char *connname = NULL;
277 : char *msg;
278 32 : PGconn *conn = NULL;
279 32 : remoteConn *rconn = NULL;
280 :
281 32 : dblink_init();
282 :
283 32 : if (PG_NARGS() == 2)
284 : {
285 22 : conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(1));
286 22 : connname = text_to_cstring(PG_GETARG_TEXT_PP(0));
287 : }
288 10 : else if (PG_NARGS() == 1)
289 10 : conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0));
290 :
291 32 : if (connname)
292 : {
293 22 : rconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext,
294 : sizeof(remoteConn));
295 22 : rconn->conn = NULL;
296 22 : rconn->openCursorCount = 0;
297 22 : rconn->newXactForCursor = false;
298 : }
299 :
300 : /* first check for valid foreign data server */
301 32 : connstr = get_connect_string(conname_or_str);
302 32 : if (connstr == NULL)
303 28 : connstr = conname_or_str;
304 :
305 : /* check password in connection string if not superuser */
306 32 : dblink_connstr_check(connstr);
307 :
308 : /* first time, allocate or get the custom wait event */
309 30 : if (dblink_we_connect == 0)
310 4 : dblink_we_connect = WaitEventExtensionNew("DblinkConnect");
311 :
312 : /* OK to make connection */
313 30 : conn = libpqsrv_connect(connstr, dblink_we_connect);
314 :
315 30 : if (PQstatus(conn) == CONNECTION_BAD)
316 : {
317 0 : msg = pchomp(PQerrorMessage(conn));
318 0 : libpqsrv_disconnect(conn);
319 0 : if (rconn)
320 0 : pfree(rconn);
321 :
322 0 : ereport(ERROR,
323 : (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
324 : errmsg("could not establish connection"),
325 : errdetail_internal("%s", msg)));
326 : }
327 :
328 : /* check password actually used if not superuser */
329 30 : dblink_security_check(conn, rconn, connstr);
330 :
331 : /* attempt to set client encoding to match server encoding, if needed */
332 30 : if (PQclientEncoding(conn) != GetDatabaseEncoding())
333 0 : PQsetClientEncoding(conn, GetDatabaseEncodingName());
334 :
335 30 : if (connname)
336 : {
337 20 : rconn->conn = conn;
338 20 : createNewConnection(connname, rconn);
339 : }
340 : else
341 : {
342 10 : if (pconn->conn)
343 2 : libpqsrv_disconnect(pconn->conn);
344 10 : pconn->conn = conn;
345 : }
346 :
347 28 : PG_RETURN_TEXT_P(cstring_to_text("OK"));
348 : }
349 :
350 : /*
351 : * Clear a persistent connection to another database
352 : */
353 12 : PG_FUNCTION_INFO_V1(dblink_disconnect);
354 : Datum
355 26 : dblink_disconnect(PG_FUNCTION_ARGS)
356 : {
357 26 : char *conname = NULL;
358 26 : remoteConn *rconn = NULL;
359 26 : PGconn *conn = NULL;
360 :
361 26 : dblink_init();
362 :
363 26 : if (PG_NARGS() == 1)
364 : {
365 18 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
366 18 : rconn = getConnectionByName(conname);
367 18 : if (rconn)
368 16 : conn = rconn->conn;
369 : }
370 : else
371 8 : conn = pconn->conn;
372 :
373 26 : if (!conn)
374 2 : dblink_conn_not_avail(conname);
375 :
376 24 : libpqsrv_disconnect(conn);
377 24 : if (rconn)
378 : {
379 16 : deleteConnection(conname);
380 16 : pfree(rconn);
381 : }
382 : else
383 8 : pconn->conn = NULL;
384 :
385 24 : PG_RETURN_TEXT_P(cstring_to_text("OK"));
386 : }
387 :
388 : /*
389 : * opens a cursor using a persistent connection
390 : */
391 18 : PG_FUNCTION_INFO_V1(dblink_open);
392 : Datum
393 18 : dblink_open(PG_FUNCTION_ARGS)
394 : {
395 18 : PGresult *res = NULL;
396 : PGconn *conn;
397 18 : char *curname = NULL;
398 18 : char *sql = NULL;
399 18 : char *conname = NULL;
400 : StringInfoData buf;
401 18 : remoteConn *rconn = NULL;
402 18 : bool fail = true; /* default to backward compatible behavior */
403 :
404 18 : dblink_init();
405 18 : initStringInfo(&buf);
406 :
407 18 : if (PG_NARGS() == 2)
408 : {
409 : /* text,text */
410 4 : curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
411 4 : sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
412 4 : rconn = pconn;
413 : }
414 14 : else if (PG_NARGS() == 3)
415 : {
416 : /* might be text,text,text or text,text,bool */
417 12 : if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID)
418 : {
419 2 : curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
420 2 : sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
421 2 : fail = PG_GETARG_BOOL(2);
422 2 : rconn = pconn;
423 : }
424 : else
425 : {
426 10 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
427 10 : curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
428 10 : sql = text_to_cstring(PG_GETARG_TEXT_PP(2));
429 10 : rconn = getConnectionByName(conname);
430 : }
431 : }
432 2 : else if (PG_NARGS() == 4)
433 : {
434 : /* text,text,text,bool */
435 2 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
436 2 : curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
437 2 : sql = text_to_cstring(PG_GETARG_TEXT_PP(2));
438 2 : fail = PG_GETARG_BOOL(3);
439 2 : rconn = getConnectionByName(conname);
440 : }
441 :
442 18 : if (!rconn || !rconn->conn)
443 0 : dblink_conn_not_avail(conname);
444 :
445 18 : conn = rconn->conn;
446 :
447 : /* If we are not in a transaction, start one */
448 18 : if (PQtransactionStatus(conn) == PQTRANS_IDLE)
449 : {
450 14 : res = libpqsrv_exec(conn, "BEGIN", dblink_we_get_result);
451 14 : if (PQresultStatus(res) != PGRES_COMMAND_OK)
452 0 : dblink_res_internalerror(conn, res, "begin error");
453 14 : PQclear(res);
454 14 : rconn->newXactForCursor = true;
455 :
456 : /*
457 : * Since transaction state was IDLE, we force cursor count to
458 : * initially be 0. This is needed as a previous ABORT might have wiped
459 : * out our transaction without maintaining the cursor count for us.
460 : */
461 14 : rconn->openCursorCount = 0;
462 : }
463 :
464 : /* if we started a transaction, increment cursor count */
465 18 : if (rconn->newXactForCursor)
466 18 : (rconn->openCursorCount)++;
467 :
468 18 : appendStringInfo(&buf, "DECLARE %s CURSOR FOR %s", curname, sql);
469 18 : res = libpqsrv_exec(conn, buf.data, dblink_we_get_result);
470 18 : if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
471 : {
472 4 : dblink_res_error(conn, conname, res, fail,
473 : "while opening cursor \"%s\"", curname);
474 4 : PG_RETURN_TEXT_P(cstring_to_text("ERROR"));
475 : }
476 :
477 14 : PQclear(res);
478 14 : PG_RETURN_TEXT_P(cstring_to_text("OK"));
479 : }
480 :
481 : /*
482 : * closes a cursor
483 : */
484 12 : PG_FUNCTION_INFO_V1(dblink_close);
485 : Datum
486 10 : dblink_close(PG_FUNCTION_ARGS)
487 : {
488 : PGconn *conn;
489 10 : PGresult *res = NULL;
490 10 : char *curname = NULL;
491 10 : char *conname = NULL;
492 : StringInfoData buf;
493 10 : remoteConn *rconn = NULL;
494 10 : bool fail = true; /* default to backward compatible behavior */
495 :
496 10 : dblink_init();
497 10 : initStringInfo(&buf);
498 :
499 10 : if (PG_NARGS() == 1)
500 : {
501 : /* text */
502 0 : curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
503 0 : rconn = pconn;
504 : }
505 10 : else if (PG_NARGS() == 2)
506 : {
507 : /* might be text,text or text,bool */
508 10 : if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
509 : {
510 4 : curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
511 4 : fail = PG_GETARG_BOOL(1);
512 4 : rconn = pconn;
513 : }
514 : else
515 : {
516 6 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
517 6 : curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
518 6 : rconn = getConnectionByName(conname);
519 : }
520 : }
521 10 : if (PG_NARGS() == 3)
522 : {
523 : /* text,text,bool */
524 0 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
525 0 : curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
526 0 : fail = PG_GETARG_BOOL(2);
527 0 : rconn = getConnectionByName(conname);
528 : }
529 :
530 10 : if (!rconn || !rconn->conn)
531 0 : dblink_conn_not_avail(conname);
532 :
533 10 : conn = rconn->conn;
534 :
535 10 : appendStringInfo(&buf, "CLOSE %s", curname);
536 :
537 : /* close the cursor */
538 10 : res = libpqsrv_exec(conn, buf.data, dblink_we_get_result);
539 10 : if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
540 : {
541 2 : dblink_res_error(conn, conname, res, fail,
542 : "while closing cursor \"%s\"", curname);
543 2 : PG_RETURN_TEXT_P(cstring_to_text("ERROR"));
544 : }
545 :
546 8 : PQclear(res);
547 :
548 : /* if we started a transaction, decrement cursor count */
549 8 : if (rconn->newXactForCursor)
550 : {
551 8 : (rconn->openCursorCount)--;
552 :
553 : /* if count is zero, commit the transaction */
554 8 : if (rconn->openCursorCount == 0)
555 : {
556 4 : rconn->newXactForCursor = false;
557 :
558 4 : res = libpqsrv_exec(conn, "COMMIT", dblink_we_get_result);
559 4 : if (PQresultStatus(res) != PGRES_COMMAND_OK)
560 0 : dblink_res_internalerror(conn, res, "commit error");
561 4 : PQclear(res);
562 : }
563 : }
564 :
565 8 : PG_RETURN_TEXT_P(cstring_to_text("OK"));
566 : }
567 :
568 : /*
569 : * Fetch results from an open cursor
570 : */
571 18 : PG_FUNCTION_INFO_V1(dblink_fetch);
572 : Datum
573 26 : dblink_fetch(PG_FUNCTION_ARGS)
574 : {
575 26 : PGresult *res = NULL;
576 26 : char *conname = NULL;
577 26 : remoteConn *rconn = NULL;
578 26 : PGconn *conn = NULL;
579 : StringInfoData buf;
580 26 : char *curname = NULL;
581 26 : int howmany = 0;
582 26 : bool fail = true; /* default to backward compatible */
583 :
584 26 : prepTuplestoreResult(fcinfo);
585 :
586 26 : dblink_init();
587 :
588 26 : if (PG_NARGS() == 4)
589 : {
590 : /* text,text,int,bool */
591 2 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
592 2 : curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
593 2 : howmany = PG_GETARG_INT32(2);
594 2 : fail = PG_GETARG_BOOL(3);
595 :
596 2 : rconn = getConnectionByName(conname);
597 2 : if (rconn)
598 2 : conn = rconn->conn;
599 : }
600 24 : else if (PG_NARGS() == 3)
601 : {
602 : /* text,text,int or text,int,bool */
603 16 : if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID)
604 : {
605 4 : curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
606 4 : howmany = PG_GETARG_INT32(1);
607 4 : fail = PG_GETARG_BOOL(2);
608 4 : conn = pconn->conn;
609 : }
610 : else
611 : {
612 12 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
613 12 : curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
614 12 : howmany = PG_GETARG_INT32(2);
615 :
616 12 : rconn = getConnectionByName(conname);
617 12 : if (rconn)
618 12 : conn = rconn->conn;
619 : }
620 : }
621 8 : else if (PG_NARGS() == 2)
622 : {
623 : /* text,int */
624 8 : curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
625 8 : howmany = PG_GETARG_INT32(1);
626 8 : conn = pconn->conn;
627 : }
628 :
629 26 : if (!conn)
630 0 : dblink_conn_not_avail(conname);
631 :
632 26 : initStringInfo(&buf);
633 26 : appendStringInfo(&buf, "FETCH %d FROM %s", howmany, curname);
634 :
635 : /*
636 : * Try to execute the query. Note that since libpq uses malloc, the
637 : * PGresult will be long-lived even though we are still in a short-lived
638 : * memory context.
639 : */
640 26 : res = libpqsrv_exec(conn, buf.data, dblink_we_get_result);
641 52 : if (!res ||
642 52 : (PQresultStatus(res) != PGRES_COMMAND_OK &&
643 26 : PQresultStatus(res) != PGRES_TUPLES_OK))
644 : {
645 10 : dblink_res_error(conn, conname, res, fail,
646 : "while fetching from cursor \"%s\"", curname);
647 6 : return (Datum) 0;
648 : }
649 16 : else if (PQresultStatus(res) == PGRES_COMMAND_OK)
650 : {
651 : /* cursor does not exist - closed already or bad name */
652 0 : PQclear(res);
653 0 : ereport(ERROR,
654 : (errcode(ERRCODE_INVALID_CURSOR_NAME),
655 : errmsg("cursor \"%s\" does not exist", curname)));
656 : }
657 :
658 16 : materializeResult(fcinfo, conn, res);
659 14 : return (Datum) 0;
660 : }
661 :
662 : /*
663 : * Note: this is the new preferred version of dblink
664 : */
665 22 : PG_FUNCTION_INFO_V1(dblink_record);
666 : Datum
667 50 : dblink_record(PG_FUNCTION_ARGS)
668 : {
669 50 : return dblink_record_internal(fcinfo, false);
670 : }
671 :
672 6 : PG_FUNCTION_INFO_V1(dblink_send_query);
673 : Datum
674 12 : dblink_send_query(PG_FUNCTION_ARGS)
675 : {
676 : PGconn *conn;
677 : char *sql;
678 : int retval;
679 :
680 12 : if (PG_NARGS() == 2)
681 : {
682 12 : conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
683 12 : sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
684 : }
685 : else
686 : /* shouldn't happen */
687 0 : elog(ERROR, "wrong number of arguments");
688 :
689 : /* async query send */
690 12 : retval = PQsendQuery(conn, sql);
691 12 : if (retval != 1)
692 0 : elog(NOTICE, "could not send query: %s", pchomp(PQerrorMessage(conn)));
693 :
694 12 : PG_RETURN_INT32(retval);
695 : }
696 :
697 8 : PG_FUNCTION_INFO_V1(dblink_get_result);
698 : Datum
699 16 : dblink_get_result(PG_FUNCTION_ARGS)
700 : {
701 16 : return dblink_record_internal(fcinfo, true);
702 : }
703 :
704 : static Datum
705 66 : dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
706 : {
707 66 : PGconn *volatile conn = NULL;
708 66 : volatile bool freeconn = false;
709 :
710 66 : prepTuplestoreResult(fcinfo);
711 :
712 66 : dblink_init();
713 :
714 66 : PG_TRY();
715 : {
716 66 : char *sql = NULL;
717 66 : char *conname = NULL;
718 66 : bool fail = true; /* default to backward compatible */
719 :
720 66 : if (!is_async)
721 : {
722 50 : if (PG_NARGS() == 3)
723 : {
724 : /* text,text,bool */
725 2 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
726 2 : sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
727 2 : fail = PG_GETARG_BOOL(2);
728 2 : dblink_get_conn(conname, &conn, &conname, &freeconn);
729 : }
730 48 : else if (PG_NARGS() == 2)
731 : {
732 : /* text,text or text,bool */
733 34 : if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
734 : {
735 2 : sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
736 2 : fail = PG_GETARG_BOOL(1);
737 2 : conn = pconn->conn;
738 : }
739 : else
740 : {
741 32 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
742 32 : sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
743 32 : dblink_get_conn(conname, &conn, &conname, &freeconn);
744 : }
745 : }
746 14 : else if (PG_NARGS() == 1)
747 : {
748 : /* text */
749 14 : conn = pconn->conn;
750 14 : sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
751 : }
752 : else
753 : /* shouldn't happen */
754 0 : elog(ERROR, "wrong number of arguments");
755 : }
756 : else /* is_async */
757 : {
758 : /* get async result */
759 16 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
760 :
761 16 : if (PG_NARGS() == 2)
762 : {
763 : /* text,bool */
764 0 : fail = PG_GETARG_BOOL(1);
765 0 : conn = dblink_get_named_conn(conname);
766 : }
767 16 : else if (PG_NARGS() == 1)
768 : {
769 : /* text */
770 16 : conn = dblink_get_named_conn(conname);
771 : }
772 : else
773 : /* shouldn't happen */
774 0 : elog(ERROR, "wrong number of arguments");
775 : }
776 :
777 62 : if (!conn)
778 4 : dblink_conn_not_avail(conname);
779 :
780 58 : if (!is_async)
781 : {
782 : /* synchronous query, use efficient tuple collection method */
783 42 : materializeQueryResult(fcinfo, conn, conname, sql, fail);
784 : }
785 : else
786 : {
787 : /* async result retrieval, do it the old way */
788 16 : PGresult *res = libpqsrv_get_result(conn, dblink_we_get_result);
789 :
790 : /* NULL means we're all done with the async results */
791 16 : if (res)
792 : {
793 10 : if (PQresultStatus(res) != PGRES_COMMAND_OK &&
794 10 : PQresultStatus(res) != PGRES_TUPLES_OK)
795 : {
796 0 : dblink_res_error(conn, conname, res, fail,
797 : "while executing query");
798 : /* if fail isn't set, we'll return an empty query result */
799 : }
800 : else
801 : {
802 10 : materializeResult(fcinfo, conn, res);
803 : }
804 : }
805 : }
806 : }
807 8 : PG_FINALLY();
808 : {
809 : /* if needed, close the connection to the database */
810 66 : if (freeconn)
811 6 : libpqsrv_disconnect(conn);
812 : }
813 66 : PG_END_TRY();
814 :
815 58 : return (Datum) 0;
816 : }
817 :
818 : /*
819 : * Verify function caller can handle a tuplestore result, and set up for that.
820 : *
821 : * Note: if the caller returns without actually creating a tuplestore, the
822 : * executor will treat the function result as an empty set.
823 : */
824 : static void
825 92 : prepTuplestoreResult(FunctionCallInfo fcinfo)
826 : {
827 92 : ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
828 :
829 : /* check to see if query supports us returning a tuplestore */
830 92 : if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
831 0 : ereport(ERROR,
832 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
833 : errmsg("set-valued function called in context that cannot accept a set")));
834 92 : if (!(rsinfo->allowedModes & SFRM_Materialize))
835 0 : ereport(ERROR,
836 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
837 : errmsg("materialize mode required, but it is not allowed in this context")));
838 :
839 : /* let the executor know we're sending back a tuplestore */
840 92 : rsinfo->returnMode = SFRM_Materialize;
841 :
842 : /* caller must fill these to return a non-empty result */
843 92 : rsinfo->setResult = NULL;
844 92 : rsinfo->setDesc = NULL;
845 92 : }
846 :
847 : /*
848 : * Copy the contents of the PGresult into a tuplestore to be returned
849 : * as the result of the current function.
850 : * The PGresult will be released in this function.
851 : */
852 : static void
853 26 : materializeResult(FunctionCallInfo fcinfo, PGconn *conn, PGresult *res)
854 : {
855 26 : ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
856 :
857 : /* prepTuplestoreResult must have been called previously */
858 : Assert(rsinfo->returnMode == SFRM_Materialize);
859 :
860 26 : PG_TRY();
861 : {
862 : TupleDesc tupdesc;
863 : bool is_sql_cmd;
864 : int ntuples;
865 : int nfields;
866 :
867 26 : if (PQresultStatus(res) == PGRES_COMMAND_OK)
868 : {
869 0 : is_sql_cmd = true;
870 :
871 : /*
872 : * need a tuple descriptor representing one TEXT column to return
873 : * the command status string as our result tuple
874 : */
875 0 : tupdesc = CreateTemplateTupleDesc(1);
876 0 : TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
877 : TEXTOID, -1, 0);
878 0 : ntuples = 1;
879 0 : nfields = 1;
880 : }
881 : else
882 : {
883 : Assert(PQresultStatus(res) == PGRES_TUPLES_OK);
884 :
885 26 : is_sql_cmd = false;
886 :
887 : /* get a tuple descriptor for our result type */
888 26 : switch (get_call_result_type(fcinfo, NULL, &tupdesc))
889 : {
890 26 : case TYPEFUNC_COMPOSITE:
891 : /* success */
892 26 : break;
893 0 : case TYPEFUNC_RECORD:
894 : /* failed to determine actual type of RECORD */
895 0 : ereport(ERROR,
896 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
897 : errmsg("function returning record called in context "
898 : "that cannot accept type record")));
899 : break;
900 0 : default:
901 : /* result type isn't composite */
902 0 : elog(ERROR, "return type must be a row type");
903 : break;
904 : }
905 :
906 : /* make sure we have a persistent copy of the tupdesc */
907 26 : tupdesc = CreateTupleDescCopy(tupdesc);
908 26 : ntuples = PQntuples(res);
909 26 : nfields = PQnfields(res);
910 : }
911 :
912 : /*
913 : * check result and tuple descriptor have the same number of columns
914 : */
915 26 : if (nfields != tupdesc->natts)
916 0 : ereport(ERROR,
917 : (errcode(ERRCODE_DATATYPE_MISMATCH),
918 : errmsg("remote query result rowtype does not match "
919 : "the specified FROM clause rowtype")));
920 :
921 26 : if (ntuples > 0)
922 : {
923 : AttInMetadata *attinmeta;
924 26 : int nestlevel = -1;
925 : Tuplestorestate *tupstore;
926 : MemoryContext oldcontext;
927 : int row;
928 : char **values;
929 :
930 26 : attinmeta = TupleDescGetAttInMetadata(tupdesc);
931 :
932 : /* Set GUCs to ensure we read GUC-sensitive data types correctly */
933 26 : if (!is_sql_cmd)
934 26 : nestlevel = applyRemoteGucs(conn);
935 :
936 26 : oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
937 26 : tupstore = tuplestore_begin_heap(true, false, work_mem);
938 26 : rsinfo->setResult = tupstore;
939 26 : rsinfo->setDesc = tupdesc;
940 26 : MemoryContextSwitchTo(oldcontext);
941 :
942 26 : values = palloc_array(char *, nfields);
943 :
944 : /* put all tuples into the tuplestore */
945 98 : for (row = 0; row < ntuples; row++)
946 : {
947 : HeapTuple tuple;
948 :
949 74 : if (!is_sql_cmd)
950 : {
951 : int i;
952 :
953 276 : for (i = 0; i < nfields; i++)
954 : {
955 202 : if (PQgetisnull(res, row, i))
956 0 : values[i] = NULL;
957 : else
958 202 : values[i] = PQgetvalue(res, row, i);
959 : }
960 : }
961 : else
962 : {
963 0 : values[0] = PQcmdStatus(res);
964 : }
965 :
966 : /* build the tuple and put it into the tuplestore. */
967 74 : tuple = BuildTupleFromCStrings(attinmeta, values);
968 72 : tuplestore_puttuple(tupstore, tuple);
969 : }
970 :
971 : /* clean up GUC settings, if we changed any */
972 24 : restoreLocalGucs(nestlevel);
973 : }
974 : }
975 2 : PG_FINALLY();
976 : {
977 : /* be sure to release the libpq result */
978 26 : PQclear(res);
979 : }
980 26 : PG_END_TRY();
981 24 : }
982 :
983 : /*
984 : * Execute the given SQL command and store its results into a tuplestore
985 : * to be returned as the result of the current function.
986 : *
987 : * This is equivalent to PQexec followed by materializeResult, but we make
988 : * use of libpq's single-row mode to avoid accumulating the whole result
989 : * inside libpq before it gets transferred to the tuplestore.
990 : */
991 : static void
992 42 : materializeQueryResult(FunctionCallInfo fcinfo,
993 : PGconn *conn,
994 : const char *conname,
995 : const char *sql,
996 : bool fail)
997 : {
998 42 : ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
999 42 : PGresult *volatile res = NULL;
1000 42 : volatile storeInfo sinfo = {0};
1001 :
1002 : /* prepTuplestoreResult must have been called previously */
1003 : Assert(rsinfo->returnMode == SFRM_Materialize);
1004 :
1005 42 : sinfo.fcinfo = fcinfo;
1006 :
1007 42 : PG_TRY();
1008 : {
1009 : /* Create short-lived memory context for data conversions */
1010 42 : sinfo.tmpcontext = AllocSetContextCreate(CurrentMemoryContext,
1011 : "dblink temporary context",
1012 : ALLOCSET_DEFAULT_SIZES);
1013 :
1014 : /* execute query, collecting any tuples into the tuplestore */
1015 42 : res = storeQueryResult(&sinfo, conn, sql);
1016 :
1017 42 : if (!res ||
1018 42 : (PQresultStatus(res) != PGRES_COMMAND_OK &&
1019 42 : PQresultStatus(res) != PGRES_TUPLES_OK))
1020 4 : {
1021 : /*
1022 : * dblink_res_error will clear the passed PGresult, so we need
1023 : * this ugly dance to avoid doing so twice during error exit
1024 : */
1025 4 : PGresult *res1 = res;
1026 :
1027 4 : res = NULL;
1028 4 : dblink_res_error(conn, conname, res1, fail,
1029 : "while executing query");
1030 : /* if fail isn't set, we'll return an empty query result */
1031 : }
1032 38 : else if (PQresultStatus(res) == PGRES_COMMAND_OK)
1033 : {
1034 : /*
1035 : * storeRow didn't get called, so we need to convert the command
1036 : * status string to a tuple manually
1037 : */
1038 : TupleDesc tupdesc;
1039 : AttInMetadata *attinmeta;
1040 : Tuplestorestate *tupstore;
1041 : HeapTuple tuple;
1042 : char *values[1];
1043 : MemoryContext oldcontext;
1044 :
1045 : /*
1046 : * need a tuple descriptor representing one TEXT column to return
1047 : * the command status string as our result tuple
1048 : */
1049 0 : tupdesc = CreateTemplateTupleDesc(1);
1050 0 : TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
1051 : TEXTOID, -1, 0);
1052 0 : attinmeta = TupleDescGetAttInMetadata(tupdesc);
1053 :
1054 0 : oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
1055 0 : tupstore = tuplestore_begin_heap(true, false, work_mem);
1056 0 : rsinfo->setResult = tupstore;
1057 0 : rsinfo->setDesc = tupdesc;
1058 0 : MemoryContextSwitchTo(oldcontext);
1059 :
1060 0 : values[0] = PQcmdStatus(res);
1061 :
1062 : /* build the tuple and put it into the tuplestore. */
1063 0 : tuple = BuildTupleFromCStrings(attinmeta, values);
1064 0 : tuplestore_puttuple(tupstore, tuple);
1065 :
1066 0 : PQclear(res);
1067 0 : res = NULL;
1068 : }
1069 : else
1070 : {
1071 : Assert(PQresultStatus(res) == PGRES_TUPLES_OK);
1072 : /* storeRow should have created a tuplestore */
1073 : Assert(rsinfo->setResult != NULL);
1074 :
1075 38 : PQclear(res);
1076 38 : res = NULL;
1077 : }
1078 :
1079 : /* clean up data conversion short-lived memory context */
1080 42 : if (sinfo.tmpcontext != NULL)
1081 42 : MemoryContextDelete(sinfo.tmpcontext);
1082 42 : sinfo.tmpcontext = NULL;
1083 :
1084 42 : PQclear(sinfo.last_res);
1085 42 : sinfo.last_res = NULL;
1086 42 : PQclear(sinfo.cur_res);
1087 42 : sinfo.cur_res = NULL;
1088 : }
1089 0 : PG_CATCH();
1090 : {
1091 : /* be sure to release any libpq result we collected */
1092 0 : PQclear(res);
1093 0 : PQclear(sinfo.last_res);
1094 0 : PQclear(sinfo.cur_res);
1095 : /* and clear out any pending data in libpq */
1096 0 : while ((res = libpqsrv_get_result(conn, dblink_we_get_result)) !=
1097 : NULL)
1098 0 : PQclear(res);
1099 0 : PG_RE_THROW();
1100 : }
1101 42 : PG_END_TRY();
1102 42 : }
1103 :
1104 : /*
1105 : * Execute query, and send any result rows to sinfo->tuplestore.
1106 : */
1107 : static PGresult *
1108 42 : storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql)
1109 : {
1110 42 : bool first = true;
1111 42 : int nestlevel = -1;
1112 : PGresult *res;
1113 :
1114 42 : if (!PQsendQuery(conn, sql))
1115 0 : elog(ERROR, "could not send query: %s", pchomp(PQerrorMessage(conn)));
1116 :
1117 42 : if (!PQsetSingleRowMode(conn)) /* shouldn't fail */
1118 0 : elog(ERROR, "failed to set single-row mode for dblink query");
1119 :
1120 : for (;;)
1121 : {
1122 348 : CHECK_FOR_INTERRUPTS();
1123 :
1124 348 : sinfo->cur_res = libpqsrv_get_result(conn, dblink_we_get_result);
1125 348 : if (!sinfo->cur_res)
1126 42 : break;
1127 :
1128 306 : if (PQresultStatus(sinfo->cur_res) == PGRES_SINGLE_TUPLE)
1129 : {
1130 : /* got one row from possibly-bigger resultset */
1131 :
1132 : /*
1133 : * Set GUCs to ensure we read GUC-sensitive data types correctly.
1134 : * We shouldn't do this until we have a row in hand, to ensure
1135 : * libpq has seen any earlier ParameterStatus protocol messages.
1136 : */
1137 264 : if (first && nestlevel < 0)
1138 38 : nestlevel = applyRemoteGucs(conn);
1139 :
1140 264 : storeRow(sinfo, sinfo->cur_res, first);
1141 :
1142 264 : PQclear(sinfo->cur_res);
1143 264 : sinfo->cur_res = NULL;
1144 264 : first = false;
1145 : }
1146 : else
1147 : {
1148 : /* if empty resultset, fill tuplestore header */
1149 42 : if (first && PQresultStatus(sinfo->cur_res) == PGRES_TUPLES_OK)
1150 0 : storeRow(sinfo, sinfo->cur_res, first);
1151 :
1152 : /* store completed result at last_res */
1153 42 : PQclear(sinfo->last_res);
1154 42 : sinfo->last_res = sinfo->cur_res;
1155 42 : sinfo->cur_res = NULL;
1156 42 : first = true;
1157 : }
1158 : }
1159 :
1160 : /* clean up GUC settings, if we changed any */
1161 42 : restoreLocalGucs(nestlevel);
1162 :
1163 : /* return last_res */
1164 42 : res = sinfo->last_res;
1165 42 : sinfo->last_res = NULL;
1166 42 : return res;
1167 : }
1168 :
1169 : /*
1170 : * Send single row to sinfo->tuplestore.
1171 : *
1172 : * If "first" is true, create the tuplestore using PGresult's metadata
1173 : * (in this case the PGresult might contain either zero or one row).
1174 : */
1175 : static void
1176 264 : storeRow(volatile storeInfo *sinfo, PGresult *res, bool first)
1177 : {
1178 264 : int nfields = PQnfields(res);
1179 : HeapTuple tuple;
1180 : int i;
1181 : MemoryContext oldcontext;
1182 :
1183 264 : if (first)
1184 : {
1185 : /* Prepare for new result set */
1186 38 : ReturnSetInfo *rsinfo = (ReturnSetInfo *) sinfo->fcinfo->resultinfo;
1187 : TupleDesc tupdesc;
1188 :
1189 : /*
1190 : * It's possible to get more than one result set if the query string
1191 : * contained multiple SQL commands. In that case, we follow PQexec's
1192 : * traditional behavior of throwing away all but the last result.
1193 : */
1194 38 : if (sinfo->tuplestore)
1195 0 : tuplestore_end(sinfo->tuplestore);
1196 38 : sinfo->tuplestore = NULL;
1197 :
1198 : /* get a tuple descriptor for our result type */
1199 38 : switch (get_call_result_type(sinfo->fcinfo, NULL, &tupdesc))
1200 : {
1201 38 : case TYPEFUNC_COMPOSITE:
1202 : /* success */
1203 38 : break;
1204 0 : case TYPEFUNC_RECORD:
1205 : /* failed to determine actual type of RECORD */
1206 0 : ereport(ERROR,
1207 : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1208 : errmsg("function returning record called in context "
1209 : "that cannot accept type record")));
1210 : break;
1211 0 : default:
1212 : /* result type isn't composite */
1213 0 : elog(ERROR, "return type must be a row type");
1214 : break;
1215 : }
1216 :
1217 : /* make sure we have a persistent copy of the tupdesc */
1218 38 : tupdesc = CreateTupleDescCopy(tupdesc);
1219 :
1220 : /* check result and tuple descriptor have the same number of columns */
1221 38 : if (nfields != tupdesc->natts)
1222 0 : ereport(ERROR,
1223 : (errcode(ERRCODE_DATATYPE_MISMATCH),
1224 : errmsg("remote query result rowtype does not match "
1225 : "the specified FROM clause rowtype")));
1226 :
1227 : /* Prepare attinmeta for later data conversions */
1228 38 : sinfo->attinmeta = TupleDescGetAttInMetadata(tupdesc);
1229 :
1230 : /* Create a new, empty tuplestore */
1231 38 : oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
1232 38 : sinfo->tuplestore = tuplestore_begin_heap(true, false, work_mem);
1233 38 : rsinfo->setResult = sinfo->tuplestore;
1234 38 : rsinfo->setDesc = tupdesc;
1235 38 : MemoryContextSwitchTo(oldcontext);
1236 :
1237 : /* Done if empty resultset */
1238 38 : if (PQntuples(res) == 0)
1239 0 : return;
1240 :
1241 : /*
1242 : * Set up sufficiently-wide string pointers array; this won't change
1243 : * in size so it's easy to preallocate.
1244 : */
1245 38 : if (sinfo->cstrs)
1246 0 : pfree(sinfo->cstrs);
1247 38 : sinfo->cstrs = palloc_array(char *, nfields);
1248 : }
1249 :
1250 : /* Should have a single-row result if we get here */
1251 : Assert(PQntuples(res) == 1);
1252 :
1253 : /*
1254 : * Do the following work in a temp context that we reset after each tuple.
1255 : * This cleans up not only the data we have direct access to, but any
1256 : * cruft the I/O functions might leak.
1257 : */
1258 264 : oldcontext = MemoryContextSwitchTo(sinfo->tmpcontext);
1259 :
1260 : /*
1261 : * Fill cstrs with null-terminated strings of column values.
1262 : */
1263 1020 : for (i = 0; i < nfields; i++)
1264 : {
1265 756 : if (PQgetisnull(res, 0, i))
1266 0 : sinfo->cstrs[i] = NULL;
1267 : else
1268 756 : sinfo->cstrs[i] = PQgetvalue(res, 0, i);
1269 : }
1270 :
1271 : /* Convert row to a tuple, and add it to the tuplestore */
1272 264 : tuple = BuildTupleFromCStrings(sinfo->attinmeta, sinfo->cstrs);
1273 :
1274 264 : tuplestore_puttuple(sinfo->tuplestore, tuple);
1275 :
1276 : /* Clean up */
1277 264 : MemoryContextSwitchTo(oldcontext);
1278 264 : MemoryContextReset(sinfo->tmpcontext);
1279 : }
1280 :
1281 : /*
1282 : * List all open dblink connections by name.
1283 : * Returns an array of all connection names.
1284 : * Takes no params
1285 : */
1286 4 : PG_FUNCTION_INFO_V1(dblink_get_connections);
1287 : Datum
1288 2 : dblink_get_connections(PG_FUNCTION_ARGS)
1289 : {
1290 : HASH_SEQ_STATUS status;
1291 : remoteConnHashEnt *hentry;
1292 2 : ArrayBuildState *astate = NULL;
1293 :
1294 2 : if (remoteConnHash)
1295 : {
1296 2 : hash_seq_init(&status, remoteConnHash);
1297 8 : while ((hentry = (remoteConnHashEnt *) hash_seq_search(&status)) != NULL)
1298 : {
1299 : /* stash away current value */
1300 6 : astate = accumArrayResult(astate,
1301 6 : CStringGetTextDatum(hentry->name),
1302 : false, TEXTOID, CurrentMemoryContext);
1303 : }
1304 : }
1305 :
1306 2 : if (astate)
1307 2 : PG_RETURN_DATUM(makeArrayResult(astate,
1308 : CurrentMemoryContext));
1309 : else
1310 0 : PG_RETURN_NULL();
1311 : }
1312 :
1313 : /*
1314 : * Checks if a given remote connection is busy
1315 : *
1316 : * Returns 1 if the connection is busy, 0 otherwise
1317 : * Params:
1318 : * text connection_name - name of the connection to check
1319 : *
1320 : */
1321 4 : PG_FUNCTION_INFO_V1(dblink_is_busy);
1322 : Datum
1323 2 : dblink_is_busy(PG_FUNCTION_ARGS)
1324 : {
1325 : PGconn *conn;
1326 :
1327 2 : dblink_init();
1328 2 : conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
1329 :
1330 2 : PQconsumeInput(conn);
1331 2 : PG_RETURN_INT32(PQisBusy(conn));
1332 : }
1333 :
1334 : /*
1335 : * Cancels a running request on a connection
1336 : *
1337 : * Returns text:
1338 : * "OK" if the cancel request has been sent correctly,
1339 : * an error message otherwise
1340 : *
1341 : * Params:
1342 : * text connection_name - name of the connection to check
1343 : *
1344 : */
1345 4 : PG_FUNCTION_INFO_V1(dblink_cancel_query);
1346 : Datum
1347 2 : dblink_cancel_query(PG_FUNCTION_ARGS)
1348 : {
1349 : PGconn *conn;
1350 : const char *msg;
1351 : TimestampTz endtime;
1352 :
1353 2 : dblink_init();
1354 2 : conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
1355 2 : endtime = TimestampTzPlusMilliseconds(GetCurrentTimestamp(),
1356 : 30000);
1357 2 : msg = libpqsrv_cancel(conn, endtime);
1358 2 : if (msg == NULL)
1359 2 : msg = "OK";
1360 :
1361 2 : PG_RETURN_TEXT_P(cstring_to_text(msg));
1362 : }
1363 :
1364 :
1365 : /*
1366 : * Get error message from a connection
1367 : *
1368 : * Returns text:
1369 : * "OK" if no error, an error message otherwise
1370 : *
1371 : * Params:
1372 : * text connection_name - name of the connection to check
1373 : *
1374 : */
1375 4 : PG_FUNCTION_INFO_V1(dblink_error_message);
1376 : Datum
1377 2 : dblink_error_message(PG_FUNCTION_ARGS)
1378 : {
1379 : char *msg;
1380 : PGconn *conn;
1381 :
1382 2 : dblink_init();
1383 2 : conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
1384 :
1385 2 : msg = PQerrorMessage(conn);
1386 2 : if (msg == NULL || msg[0] == '\0')
1387 2 : PG_RETURN_TEXT_P(cstring_to_text("OK"));
1388 : else
1389 0 : PG_RETURN_TEXT_P(cstring_to_text(pchomp(msg)));
1390 : }
1391 :
1392 : /*
1393 : * Execute an SQL non-SELECT command
1394 : */
1395 18 : PG_FUNCTION_INFO_V1(dblink_exec);
1396 : Datum
1397 52 : dblink_exec(PG_FUNCTION_ARGS)
1398 : {
1399 52 : text *volatile sql_cmd_status = NULL;
1400 52 : PGconn *volatile conn = NULL;
1401 52 : volatile bool freeconn = false;
1402 :
1403 52 : dblink_init();
1404 :
1405 52 : PG_TRY();
1406 : {
1407 52 : PGresult *res = NULL;
1408 52 : char *sql = NULL;
1409 52 : char *conname = NULL;
1410 52 : bool fail = true; /* default to backward compatible behavior */
1411 :
1412 52 : if (PG_NARGS() == 3)
1413 : {
1414 : /* must be text,text,bool */
1415 0 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
1416 0 : sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
1417 0 : fail = PG_GETARG_BOOL(2);
1418 0 : dblink_get_conn(conname, &conn, &conname, &freeconn);
1419 : }
1420 52 : else if (PG_NARGS() == 2)
1421 : {
1422 : /* might be text,text or text,bool */
1423 34 : if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
1424 : {
1425 2 : sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
1426 2 : fail = PG_GETARG_BOOL(1);
1427 2 : conn = pconn->conn;
1428 : }
1429 : else
1430 : {
1431 32 : conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
1432 32 : sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
1433 32 : dblink_get_conn(conname, &conn, &conname, &freeconn);
1434 : }
1435 : }
1436 18 : else if (PG_NARGS() == 1)
1437 : {
1438 : /* must be single text argument */
1439 18 : conn = pconn->conn;
1440 18 : sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
1441 : }
1442 : else
1443 : /* shouldn't happen */
1444 0 : elog(ERROR, "wrong number of arguments");
1445 :
1446 52 : if (!conn)
1447 0 : dblink_conn_not_avail(conname);
1448 :
1449 52 : res = libpqsrv_exec(conn, sql, dblink_we_get_result);
1450 52 : if (!res ||
1451 52 : (PQresultStatus(res) != PGRES_COMMAND_OK &&
1452 4 : PQresultStatus(res) != PGRES_TUPLES_OK))
1453 : {
1454 4 : dblink_res_error(conn, conname, res, fail,
1455 : "while executing command");
1456 :
1457 : /*
1458 : * and save a copy of the command status string to return as our
1459 : * result tuple
1460 : */
1461 2 : sql_cmd_status = cstring_to_text("ERROR");
1462 : }
1463 48 : else if (PQresultStatus(res) == PGRES_COMMAND_OK)
1464 : {
1465 : /*
1466 : * and save a copy of the command status string to return as our
1467 : * result tuple
1468 : */
1469 48 : sql_cmd_status = cstring_to_text(PQcmdStatus(res));
1470 48 : PQclear(res);
1471 : }
1472 : else
1473 : {
1474 0 : PQclear(res);
1475 0 : ereport(ERROR,
1476 : (errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
1477 : errmsg("statement returning results not allowed")));
1478 : }
1479 : }
1480 2 : PG_FINALLY();
1481 : {
1482 : /* if needed, close the connection to the database */
1483 52 : if (freeconn)
1484 2 : libpqsrv_disconnect(conn);
1485 : }
1486 52 : PG_END_TRY();
1487 :
1488 50 : PG_RETURN_TEXT_P(sql_cmd_status);
1489 : }
1490 :
1491 :
1492 : /*
1493 : * dblink_get_pkey
1494 : *
1495 : * Return list of primary key fields for the supplied relation,
1496 : * or NULL if none exists.
1497 : */
1498 4 : PG_FUNCTION_INFO_V1(dblink_get_pkey);
1499 : Datum
1500 18 : dblink_get_pkey(PG_FUNCTION_ARGS)
1501 : {
1502 : int16 indnkeyatts;
1503 : char **results;
1504 : FuncCallContext *funcctx;
1505 : int32 call_cntr;
1506 : int32 max_calls;
1507 : AttInMetadata *attinmeta;
1508 : MemoryContext oldcontext;
1509 :
1510 : /* stuff done only on the first call of the function */
1511 18 : if (SRF_IS_FIRSTCALL())
1512 : {
1513 : Relation rel;
1514 : TupleDesc tupdesc;
1515 :
1516 : /* create a function context for cross-call persistence */
1517 6 : funcctx = SRF_FIRSTCALL_INIT();
1518 :
1519 : /*
1520 : * switch to memory context appropriate for multiple function calls
1521 : */
1522 6 : oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
1523 :
1524 : /* open target relation */
1525 6 : rel = get_rel_from_relname(PG_GETARG_TEXT_PP(0), AccessShareLock, ACL_SELECT);
1526 :
1527 : /* get the array of attnums */
1528 6 : results = get_pkey_attnames(rel, &indnkeyatts);
1529 :
1530 6 : relation_close(rel, AccessShareLock);
1531 :
1532 : /*
1533 : * need a tuple descriptor representing one INT and one TEXT column
1534 : */
1535 6 : tupdesc = CreateTemplateTupleDesc(2);
1536 6 : TupleDescInitEntry(tupdesc, (AttrNumber) 1, "position",
1537 : INT4OID, -1, 0);
1538 6 : TupleDescInitEntry(tupdesc, (AttrNumber) 2, "colname",
1539 : TEXTOID, -1, 0);
1540 :
1541 : /*
1542 : * Generate attribute metadata needed later to produce tuples from raw
1543 : * C strings
1544 : */
1545 6 : attinmeta = TupleDescGetAttInMetadata(tupdesc);
1546 6 : funcctx->attinmeta = attinmeta;
1547 :
1548 6 : if ((results != NULL) && (indnkeyatts > 0))
1549 : {
1550 6 : funcctx->max_calls = indnkeyatts;
1551 :
1552 : /* got results, keep track of them */
1553 6 : funcctx->user_fctx = results;
1554 : }
1555 : else
1556 : {
1557 : /* fast track when no results */
1558 0 : MemoryContextSwitchTo(oldcontext);
1559 0 : SRF_RETURN_DONE(funcctx);
1560 : }
1561 :
1562 6 : MemoryContextSwitchTo(oldcontext);
1563 : }
1564 :
1565 : /* stuff done on every call of the function */
1566 18 : funcctx = SRF_PERCALL_SETUP();
1567 :
1568 : /*
1569 : * initialize per-call variables
1570 : */
1571 18 : call_cntr = funcctx->call_cntr;
1572 18 : max_calls = funcctx->max_calls;
1573 :
1574 18 : results = (char **) funcctx->user_fctx;
1575 18 : attinmeta = funcctx->attinmeta;
1576 :
1577 18 : if (call_cntr < max_calls) /* do when there is more left to send */
1578 : {
1579 : char **values;
1580 : HeapTuple tuple;
1581 : Datum result;
1582 :
1583 12 : values = palloc_array(char *, 2);
1584 12 : values[0] = psprintf("%d", call_cntr + 1);
1585 12 : values[1] = results[call_cntr];
1586 :
1587 : /* build the tuple */
1588 12 : tuple = BuildTupleFromCStrings(attinmeta, values);
1589 :
1590 : /* make the tuple into a datum */
1591 12 : result = HeapTupleGetDatum(tuple);
1592 :
1593 12 : SRF_RETURN_NEXT(funcctx, result);
1594 : }
1595 : else
1596 : {
1597 : /* do when there is no more left */
1598 6 : SRF_RETURN_DONE(funcctx);
1599 : }
1600 : }
1601 :
1602 :
1603 : /*
1604 : * dblink_build_sql_insert
1605 : *
1606 : * Used to generate an SQL insert statement
1607 : * based on an existing tuple in a local relation.
1608 : * This is useful for selectively replicating data
1609 : * to another server via dblink.
1610 : *
1611 : * API:
1612 : * <relname> - name of local table of interest
1613 : * <pkattnums> - an int2vector of attnums which will be used
1614 : * to identify the local tuple of interest
1615 : * <pknumatts> - number of attnums in pkattnums
1616 : * <src_pkattvals_arry> - text array of key values which will be used
1617 : * to identify the local tuple of interest
1618 : * <tgt_pkattvals_arry> - text array of key values which will be used
1619 : * to build the string for execution remotely. These are substituted
1620 : * for their counterparts in src_pkattvals_arry
1621 : */
1622 6 : PG_FUNCTION_INFO_V1(dblink_build_sql_insert);
1623 : Datum
1624 12 : dblink_build_sql_insert(PG_FUNCTION_ARGS)
1625 : {
1626 12 : text *relname_text = PG_GETARG_TEXT_PP(0);
1627 12 : int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1628 12 : int32 pknumatts_arg = PG_GETARG_INT32(2);
1629 12 : ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
1630 12 : ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
1631 : Relation rel;
1632 : int *pkattnums;
1633 : int pknumatts;
1634 : char **src_pkattvals;
1635 : char **tgt_pkattvals;
1636 : int src_nitems;
1637 : int tgt_nitems;
1638 : char *sql;
1639 :
1640 : /*
1641 : * Open target relation.
1642 : */
1643 12 : rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1644 :
1645 : /*
1646 : * Process pkattnums argument.
1647 : */
1648 12 : validate_pkattnums(rel, pkattnums_arg, pknumatts_arg,
1649 : &pkattnums, &pknumatts);
1650 :
1651 : /*
1652 : * Source array is made up of key values that will be used to locate the
1653 : * tuple of interest from the local system.
1654 : */
1655 8 : src_pkattvals = get_text_array_contents(src_pkattvals_arry, &src_nitems);
1656 :
1657 : /*
1658 : * There should be one source array key value for each key attnum
1659 : */
1660 8 : if (src_nitems != pknumatts)
1661 0 : ereport(ERROR,
1662 : (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1663 : errmsg("source key array length must match number of key attributes")));
1664 :
1665 : /*
1666 : * Target array is made up of key values that will be used to build the
1667 : * SQL string for use on the remote system.
1668 : */
1669 8 : tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
1670 :
1671 : /*
1672 : * There should be one target array key value for each key attnum
1673 : */
1674 8 : if (tgt_nitems != pknumatts)
1675 0 : ereport(ERROR,
1676 : (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1677 : errmsg("target key array length must match number of key attributes")));
1678 :
1679 : /*
1680 : * Prep work is finally done. Go get the SQL string.
1681 : */
1682 8 : sql = get_sql_insert(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
1683 :
1684 : /*
1685 : * Now we can close the relation.
1686 : */
1687 8 : relation_close(rel, AccessShareLock);
1688 :
1689 : /*
1690 : * And send it
1691 : */
1692 8 : PG_RETURN_TEXT_P(cstring_to_text(sql));
1693 : }
1694 :
1695 :
1696 : /*
1697 : * dblink_build_sql_delete
1698 : *
1699 : * Used to generate an SQL delete statement.
1700 : * This is useful for selectively replicating a
1701 : * delete to another server via dblink.
1702 : *
1703 : * API:
1704 : * <relname> - name of remote table of interest
1705 : * <pkattnums> - an int2vector of attnums which will be used
1706 : * to identify the remote tuple of interest
1707 : * <pknumatts> - number of attnums in pkattnums
1708 : * <tgt_pkattvals_arry> - text array of key values which will be used
1709 : * to build the string for execution remotely.
1710 : */
1711 6 : PG_FUNCTION_INFO_V1(dblink_build_sql_delete);
1712 : Datum
1713 12 : dblink_build_sql_delete(PG_FUNCTION_ARGS)
1714 : {
1715 12 : text *relname_text = PG_GETARG_TEXT_PP(0);
1716 12 : int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1717 12 : int32 pknumatts_arg = PG_GETARG_INT32(2);
1718 12 : ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
1719 : Relation rel;
1720 : int *pkattnums;
1721 : int pknumatts;
1722 : char **tgt_pkattvals;
1723 : int tgt_nitems;
1724 : char *sql;
1725 :
1726 : /*
1727 : * Open target relation.
1728 : */
1729 12 : rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1730 :
1731 : /*
1732 : * Process pkattnums argument.
1733 : */
1734 12 : validate_pkattnums(rel, pkattnums_arg, pknumatts_arg,
1735 : &pkattnums, &pknumatts);
1736 :
1737 : /*
1738 : * Target array is made up of key values that will be used to build the
1739 : * SQL string for use on the remote system.
1740 : */
1741 8 : tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
1742 :
1743 : /*
1744 : * There should be one target array key value for each key attnum
1745 : */
1746 8 : if (tgt_nitems != pknumatts)
1747 0 : ereport(ERROR,
1748 : (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1749 : errmsg("target key array length must match number of key attributes")));
1750 :
1751 : /*
1752 : * Prep work is finally done. Go get the SQL string.
1753 : */
1754 8 : sql = get_sql_delete(rel, pkattnums, pknumatts, tgt_pkattvals);
1755 :
1756 : /*
1757 : * Now we can close the relation.
1758 : */
1759 8 : relation_close(rel, AccessShareLock);
1760 :
1761 : /*
1762 : * And send it
1763 : */
1764 8 : PG_RETURN_TEXT_P(cstring_to_text(sql));
1765 : }
1766 :
1767 :
1768 : /*
1769 : * dblink_build_sql_update
1770 : *
1771 : * Used to generate an SQL update statement
1772 : * based on an existing tuple in a local relation.
1773 : * This is useful for selectively replicating data
1774 : * to another server via dblink.
1775 : *
1776 : * API:
1777 : * <relname> - name of local table of interest
1778 : * <pkattnums> - an int2vector of attnums which will be used
1779 : * to identify the local tuple of interest
1780 : * <pknumatts> - number of attnums in pkattnums
1781 : * <src_pkattvals_arry> - text array of key values which will be used
1782 : * to identify the local tuple of interest
1783 : * <tgt_pkattvals_arry> - text array of key values which will be used
1784 : * to build the string for execution remotely. These are substituted
1785 : * for their counterparts in src_pkattvals_arry
1786 : */
1787 6 : PG_FUNCTION_INFO_V1(dblink_build_sql_update);
1788 : Datum
1789 12 : dblink_build_sql_update(PG_FUNCTION_ARGS)
1790 : {
1791 12 : text *relname_text = PG_GETARG_TEXT_PP(0);
1792 12 : int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1793 12 : int32 pknumatts_arg = PG_GETARG_INT32(2);
1794 12 : ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
1795 12 : ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
1796 : Relation rel;
1797 : int *pkattnums;
1798 : int pknumatts;
1799 : char **src_pkattvals;
1800 : char **tgt_pkattvals;
1801 : int src_nitems;
1802 : int tgt_nitems;
1803 : char *sql;
1804 :
1805 : /*
1806 : * Open target relation.
1807 : */
1808 12 : rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1809 :
1810 : /*
1811 : * Process pkattnums argument.
1812 : */
1813 12 : validate_pkattnums(rel, pkattnums_arg, pknumatts_arg,
1814 : &pkattnums, &pknumatts);
1815 :
1816 : /*
1817 : * Source array is made up of key values that will be used to locate the
1818 : * tuple of interest from the local system.
1819 : */
1820 8 : src_pkattvals = get_text_array_contents(src_pkattvals_arry, &src_nitems);
1821 :
1822 : /*
1823 : * There should be one source array key value for each key attnum
1824 : */
1825 8 : if (src_nitems != pknumatts)
1826 0 : ereport(ERROR,
1827 : (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1828 : errmsg("source key array length must match number of key attributes")));
1829 :
1830 : /*
1831 : * Target array is made up of key values that will be used to build the
1832 : * SQL string for use on the remote system.
1833 : */
1834 8 : tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
1835 :
1836 : /*
1837 : * There should be one target array key value for each key attnum
1838 : */
1839 8 : if (tgt_nitems != pknumatts)
1840 0 : ereport(ERROR,
1841 : (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1842 : errmsg("target key array length must match number of key attributes")));
1843 :
1844 : /*
1845 : * Prep work is finally done. Go get the SQL string.
1846 : */
1847 8 : sql = get_sql_update(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
1848 :
1849 : /*
1850 : * Now we can close the relation.
1851 : */
1852 8 : relation_close(rel, AccessShareLock);
1853 :
1854 : /*
1855 : * And send it
1856 : */
1857 8 : PG_RETURN_TEXT_P(cstring_to_text(sql));
1858 : }
1859 :
1860 : /*
1861 : * dblink_current_query
1862 : * return the current query string
1863 : * to allow its use in (among other things)
1864 : * rewrite rules
1865 : */
1866 2 : PG_FUNCTION_INFO_V1(dblink_current_query);
1867 : Datum
1868 0 : dblink_current_query(PG_FUNCTION_ARGS)
1869 : {
1870 : /* This is now just an alias for the built-in function current_query() */
1871 0 : PG_RETURN_DATUM(current_query(fcinfo));
1872 : }
1873 :
1874 : /*
1875 : * Retrieve async notifications for a connection.
1876 : *
1877 : * Returns a setof record of notifications, or an empty set if none received.
1878 : * Can optionally take a named connection as parameter, but uses the unnamed
1879 : * connection per default.
1880 : *
1881 : */
1882 : #define DBLINK_NOTIFY_COLS 3
1883 :
1884 6 : PG_FUNCTION_INFO_V1(dblink_get_notify);
1885 : Datum
1886 4 : dblink_get_notify(PG_FUNCTION_ARGS)
1887 : {
1888 : PGconn *conn;
1889 : PGnotify *notify;
1890 4 : ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
1891 :
1892 4 : dblink_init();
1893 4 : if (PG_NARGS() == 1)
1894 0 : conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
1895 : else
1896 4 : conn = pconn->conn;
1897 :
1898 4 : InitMaterializedSRF(fcinfo, 0);
1899 :
1900 4 : PQconsumeInput(conn);
1901 8 : while ((notify = PQnotifies(conn)) != NULL)
1902 : {
1903 : Datum values[DBLINK_NOTIFY_COLS];
1904 : bool nulls[DBLINK_NOTIFY_COLS];
1905 :
1906 4 : memset(values, 0, sizeof(values));
1907 4 : memset(nulls, 0, sizeof(nulls));
1908 :
1909 4 : if (notify->relname != NULL)
1910 4 : values[0] = CStringGetTextDatum(notify->relname);
1911 : else
1912 0 : nulls[0] = true;
1913 :
1914 4 : values[1] = Int32GetDatum(notify->be_pid);
1915 :
1916 4 : if (notify->extra != NULL)
1917 4 : values[2] = CStringGetTextDatum(notify->extra);
1918 : else
1919 0 : nulls[2] = true;
1920 :
1921 4 : tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
1922 :
1923 4 : PQfreemem(notify);
1924 4 : PQconsumeInput(conn);
1925 : }
1926 :
1927 4 : return (Datum) 0;
1928 : }
1929 :
1930 : /*
1931 : * Validate the options given to a dblink foreign server or user mapping.
1932 : * Raise an error if any option is invalid.
1933 : *
1934 : * We just check the names of options here, so semantic errors in options,
1935 : * such as invalid numeric format, will be detected at the attempt to connect.
1936 : */
1937 6 : PG_FUNCTION_INFO_V1(dblink_fdw_validator);
1938 : Datum
1939 10 : dblink_fdw_validator(PG_FUNCTION_ARGS)
1940 : {
1941 10 : List *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
1942 10 : Oid context = PG_GETARG_OID(1);
1943 : ListCell *cell;
1944 :
1945 : static const PQconninfoOption *options = NULL;
1946 :
1947 : /*
1948 : * Get list of valid libpq options.
1949 : *
1950 : * To avoid unnecessary work, we get the list once and use it throughout
1951 : * the lifetime of this backend process. We don't need to care about
1952 : * memory context issues, because PQconndefaults allocates with malloc.
1953 : */
1954 10 : if (!options)
1955 : {
1956 4 : options = PQconndefaults();
1957 4 : if (!options) /* assume reason for failure is OOM */
1958 0 : ereport(ERROR,
1959 : (errcode(ERRCODE_FDW_OUT_OF_MEMORY),
1960 : errmsg("out of memory"),
1961 : errdetail("Could not get libpq's default connection options.")));
1962 : }
1963 :
1964 : /* Validate each supplied option. */
1965 16 : foreach(cell, options_list)
1966 : {
1967 10 : DefElem *def = (DefElem *) lfirst(cell);
1968 :
1969 10 : if (!is_valid_dblink_option(options, def->defname, context))
1970 : {
1971 : /*
1972 : * Unknown option, or invalid option for the context specified, so
1973 : * complain about it. Provide a hint with a valid option that
1974 : * looks similar, if there is one.
1975 : */
1976 : const PQconninfoOption *opt;
1977 : const char *closest_match;
1978 : ClosestMatchState match_state;
1979 4 : bool has_valid_options = false;
1980 :
1981 4 : initClosestMatch(&match_state, def->defname, 4);
1982 168 : for (opt = options; opt->keyword; opt++)
1983 : {
1984 164 : if (is_valid_dblink_option(options, opt->keyword, context))
1985 : {
1986 6 : has_valid_options = true;
1987 6 : updateClosestMatch(&match_state, opt->keyword);
1988 : }
1989 : }
1990 :
1991 4 : closest_match = getClosestMatch(&match_state);
1992 4 : ereport(ERROR,
1993 : (errcode(ERRCODE_FDW_OPTION_NAME_NOT_FOUND),
1994 : errmsg("invalid option \"%s\"", def->defname),
1995 : has_valid_options ? closest_match ?
1996 : errhint("Perhaps you meant the option \"%s\".",
1997 : closest_match) : 0 :
1998 : errhint("There are no valid options in this context.")));
1999 : }
2000 : }
2001 :
2002 6 : PG_RETURN_VOID();
2003 : }
2004 :
2005 :
2006 : /*************************************************************
2007 : * internal functions
2008 : */
2009 :
2010 :
2011 : /*
2012 : * get_pkey_attnames
2013 : *
2014 : * Get the primary key attnames for the given relation.
2015 : * Return NULL, and set indnkeyatts = 0, if no primary key exists.
2016 : */
2017 : static char **
2018 6 : get_pkey_attnames(Relation rel, int16 *indnkeyatts)
2019 : {
2020 : Relation indexRelation;
2021 : ScanKeyData skey;
2022 : SysScanDesc scan;
2023 : HeapTuple indexTuple;
2024 : int i;
2025 6 : char **result = NULL;
2026 : TupleDesc tupdesc;
2027 :
2028 : /* initialize indnkeyatts to 0 in case no primary key exists */
2029 6 : *indnkeyatts = 0;
2030 :
2031 6 : tupdesc = rel->rd_att;
2032 :
2033 : /* Prepare to scan pg_index for entries having indrelid = this rel. */
2034 6 : indexRelation = table_open(IndexRelationId, AccessShareLock);
2035 6 : ScanKeyInit(&skey,
2036 : Anum_pg_index_indrelid,
2037 : BTEqualStrategyNumber, F_OIDEQ,
2038 : ObjectIdGetDatum(RelationGetRelid(rel)));
2039 :
2040 6 : scan = systable_beginscan(indexRelation, IndexIndrelidIndexId, true,
2041 : NULL, 1, &skey);
2042 :
2043 6 : while (HeapTupleIsValid(indexTuple = systable_getnext(scan)))
2044 : {
2045 6 : Form_pg_index index = (Form_pg_index) GETSTRUCT(indexTuple);
2046 :
2047 : /* we're only interested if it is the primary key */
2048 6 : if (index->indisprimary)
2049 : {
2050 6 : *indnkeyatts = index->indnkeyatts;
2051 6 : if (*indnkeyatts > 0)
2052 : {
2053 6 : result = palloc_array(char *, *indnkeyatts);
2054 :
2055 18 : for (i = 0; i < *indnkeyatts; i++)
2056 12 : result[i] = SPI_fname(tupdesc, index->indkey.values[i]);
2057 : }
2058 6 : break;
2059 : }
2060 : }
2061 :
2062 6 : systable_endscan(scan);
2063 6 : table_close(indexRelation, AccessShareLock);
2064 :
2065 6 : return result;
2066 : }
2067 :
2068 : /*
2069 : * Deconstruct a text[] into C-strings (note any NULL elements will be
2070 : * returned as NULL pointers)
2071 : */
2072 : static char **
2073 40 : get_text_array_contents(ArrayType *array, int *numitems)
2074 : {
2075 40 : int ndim = ARR_NDIM(array);
2076 40 : int *dims = ARR_DIMS(array);
2077 : int nitems;
2078 : int16 typlen;
2079 : bool typbyval;
2080 : char typalign;
2081 : char **values;
2082 : char *ptr;
2083 : bits8 *bitmap;
2084 : int bitmask;
2085 : int i;
2086 :
2087 : Assert(ARR_ELEMTYPE(array) == TEXTOID);
2088 :
2089 40 : *numitems = nitems = ArrayGetNItems(ndim, dims);
2090 :
2091 40 : get_typlenbyvalalign(ARR_ELEMTYPE(array),
2092 : &typlen, &typbyval, &typalign);
2093 :
2094 40 : values = palloc_array(char *, nitems);
2095 :
2096 40 : ptr = ARR_DATA_PTR(array);
2097 40 : bitmap = ARR_NULLBITMAP(array);
2098 40 : bitmask = 1;
2099 :
2100 110 : for (i = 0; i < nitems; i++)
2101 : {
2102 70 : if (bitmap && (*bitmap & bitmask) == 0)
2103 : {
2104 0 : values[i] = NULL;
2105 : }
2106 : else
2107 : {
2108 70 : values[i] = TextDatumGetCString(PointerGetDatum(ptr));
2109 70 : ptr = att_addlength_pointer(ptr, typlen, ptr);
2110 70 : ptr = (char *) att_align_nominal(ptr, typalign);
2111 : }
2112 :
2113 : /* advance bitmap pointer if any */
2114 70 : if (bitmap)
2115 : {
2116 0 : bitmask <<= 1;
2117 0 : if (bitmask == 0x100)
2118 : {
2119 0 : bitmap++;
2120 0 : bitmask = 1;
2121 : }
2122 : }
2123 : }
2124 :
2125 40 : return values;
2126 : }
2127 :
2128 : static char *
2129 8 : get_sql_insert(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals)
2130 : {
2131 : char *relname;
2132 : HeapTuple tuple;
2133 : TupleDesc tupdesc;
2134 : int natts;
2135 : StringInfoData buf;
2136 : char *val;
2137 : int key;
2138 : int i;
2139 : bool needComma;
2140 :
2141 8 : initStringInfo(&buf);
2142 :
2143 : /* get relation name including any needed schema prefix and quoting */
2144 8 : relname = generate_relation_name(rel);
2145 :
2146 8 : tupdesc = rel->rd_att;
2147 8 : natts = tupdesc->natts;
2148 :
2149 8 : tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
2150 8 : if (!tuple)
2151 0 : ereport(ERROR,
2152 : (errcode(ERRCODE_CARDINALITY_VIOLATION),
2153 : errmsg("source row not found")));
2154 :
2155 8 : appendStringInfo(&buf, "INSERT INTO %s(", relname);
2156 :
2157 8 : needComma = false;
2158 38 : for (i = 0; i < natts; i++)
2159 : {
2160 30 : Form_pg_attribute att = TupleDescAttr(tupdesc, i);
2161 :
2162 30 : if (att->attisdropped)
2163 4 : continue;
2164 :
2165 26 : if (needComma)
2166 18 : appendStringInfoChar(&buf, ',');
2167 :
2168 26 : appendStringInfoString(&buf,
2169 26 : quote_ident_cstr(NameStr(att->attname)));
2170 26 : needComma = true;
2171 : }
2172 :
2173 8 : appendStringInfoString(&buf, ") VALUES(");
2174 :
2175 : /*
2176 : * Note: i is physical column number (counting from 0).
2177 : */
2178 8 : needComma = false;
2179 38 : for (i = 0; i < natts; i++)
2180 : {
2181 30 : if (TupleDescAttr(tupdesc, i)->attisdropped)
2182 4 : continue;
2183 :
2184 26 : if (needComma)
2185 18 : appendStringInfoChar(&buf, ',');
2186 :
2187 26 : key = get_attnum_pk_pos(pkattnums, pknumatts, i);
2188 :
2189 26 : if (key >= 0)
2190 14 : val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
2191 : else
2192 12 : val = SPI_getvalue(tuple, tupdesc, i + 1);
2193 :
2194 26 : if (val != NULL)
2195 : {
2196 26 : appendStringInfoString(&buf, quote_literal_cstr(val));
2197 26 : pfree(val);
2198 : }
2199 : else
2200 0 : appendStringInfoString(&buf, "NULL");
2201 26 : needComma = true;
2202 : }
2203 8 : appendStringInfoChar(&buf, ')');
2204 :
2205 8 : return buf.data;
2206 : }
2207 :
2208 : static char *
2209 8 : get_sql_delete(Relation rel, int *pkattnums, int pknumatts, char **tgt_pkattvals)
2210 : {
2211 : char *relname;
2212 : TupleDesc tupdesc;
2213 : StringInfoData buf;
2214 : int i;
2215 :
2216 8 : initStringInfo(&buf);
2217 :
2218 : /* get relation name including any needed schema prefix and quoting */
2219 8 : relname = generate_relation_name(rel);
2220 :
2221 8 : tupdesc = rel->rd_att;
2222 :
2223 8 : appendStringInfo(&buf, "DELETE FROM %s WHERE ", relname);
2224 22 : for (i = 0; i < pknumatts; i++)
2225 : {
2226 14 : int pkattnum = pkattnums[i];
2227 14 : Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2228 :
2229 14 : if (i > 0)
2230 6 : appendStringInfoString(&buf, " AND ");
2231 :
2232 14 : appendStringInfoString(&buf,
2233 14 : quote_ident_cstr(NameStr(attr->attname)));
2234 :
2235 14 : if (tgt_pkattvals[i] != NULL)
2236 14 : appendStringInfo(&buf, " = %s",
2237 14 : quote_literal_cstr(tgt_pkattvals[i]));
2238 : else
2239 0 : appendStringInfoString(&buf, " IS NULL");
2240 : }
2241 :
2242 8 : return buf.data;
2243 : }
2244 :
2245 : static char *
2246 8 : get_sql_update(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals)
2247 : {
2248 : char *relname;
2249 : HeapTuple tuple;
2250 : TupleDesc tupdesc;
2251 : int natts;
2252 : StringInfoData buf;
2253 : char *val;
2254 : int key;
2255 : int i;
2256 : bool needComma;
2257 :
2258 8 : initStringInfo(&buf);
2259 :
2260 : /* get relation name including any needed schema prefix and quoting */
2261 8 : relname = generate_relation_name(rel);
2262 :
2263 8 : tupdesc = rel->rd_att;
2264 8 : natts = tupdesc->natts;
2265 :
2266 8 : tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
2267 8 : if (!tuple)
2268 0 : ereport(ERROR,
2269 : (errcode(ERRCODE_CARDINALITY_VIOLATION),
2270 : errmsg("source row not found")));
2271 :
2272 8 : appendStringInfo(&buf, "UPDATE %s SET ", relname);
2273 :
2274 : /*
2275 : * Note: i is physical column number (counting from 0).
2276 : */
2277 8 : needComma = false;
2278 38 : for (i = 0; i < natts; i++)
2279 : {
2280 30 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
2281 :
2282 30 : if (attr->attisdropped)
2283 4 : continue;
2284 :
2285 26 : if (needComma)
2286 18 : appendStringInfoString(&buf, ", ");
2287 :
2288 26 : appendStringInfo(&buf, "%s = ",
2289 26 : quote_ident_cstr(NameStr(attr->attname)));
2290 :
2291 26 : key = get_attnum_pk_pos(pkattnums, pknumatts, i);
2292 :
2293 26 : if (key >= 0)
2294 14 : val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
2295 : else
2296 12 : val = SPI_getvalue(tuple, tupdesc, i + 1);
2297 :
2298 26 : if (val != NULL)
2299 : {
2300 26 : appendStringInfoString(&buf, quote_literal_cstr(val));
2301 26 : pfree(val);
2302 : }
2303 : else
2304 0 : appendStringInfoString(&buf, "NULL");
2305 26 : needComma = true;
2306 : }
2307 :
2308 8 : appendStringInfoString(&buf, " WHERE ");
2309 :
2310 22 : for (i = 0; i < pknumatts; i++)
2311 : {
2312 14 : int pkattnum = pkattnums[i];
2313 14 : Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2314 :
2315 14 : if (i > 0)
2316 6 : appendStringInfoString(&buf, " AND ");
2317 :
2318 14 : appendStringInfoString(&buf,
2319 14 : quote_ident_cstr(NameStr(attr->attname)));
2320 :
2321 14 : val = tgt_pkattvals[i];
2322 :
2323 14 : if (val != NULL)
2324 14 : appendStringInfo(&buf, " = %s", quote_literal_cstr(val));
2325 : else
2326 0 : appendStringInfoString(&buf, " IS NULL");
2327 : }
2328 :
2329 8 : return buf.data;
2330 : }
2331 :
2332 : /*
2333 : * Return a properly quoted identifier.
2334 : * Uses quote_ident in quote.c
2335 : */
2336 : static char *
2337 160 : quote_ident_cstr(char *rawstr)
2338 : {
2339 : text *rawstr_text;
2340 : text *result_text;
2341 : char *result;
2342 :
2343 160 : rawstr_text = cstring_to_text(rawstr);
2344 160 : result_text = DatumGetTextPP(DirectFunctionCall1(quote_ident,
2345 : PointerGetDatum(rawstr_text)));
2346 160 : result = text_to_cstring(result_text);
2347 :
2348 160 : return result;
2349 : }
2350 :
2351 : static int
2352 52 : get_attnum_pk_pos(int *pkattnums, int pknumatts, int key)
2353 : {
2354 : int i;
2355 :
2356 : /*
2357 : * Not likely a long list anyway, so just scan for the value
2358 : */
2359 100 : for (i = 0; i < pknumatts; i++)
2360 76 : if (key == pkattnums[i])
2361 28 : return i;
2362 :
2363 24 : return -1;
2364 : }
2365 :
2366 : static HeapTuple
2367 16 : get_tuple_of_interest(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals)
2368 : {
2369 : char *relname;
2370 : TupleDesc tupdesc;
2371 : int natts;
2372 : StringInfoData buf;
2373 : int ret;
2374 : HeapTuple tuple;
2375 : int i;
2376 :
2377 : /*
2378 : * Connect to SPI manager
2379 : */
2380 16 : if ((ret = SPI_connect()) < 0)
2381 : /* internal error */
2382 0 : elog(ERROR, "SPI connect failure - returned %d", ret);
2383 :
2384 16 : initStringInfo(&buf);
2385 :
2386 : /* get relation name including any needed schema prefix and quoting */
2387 16 : relname = generate_relation_name(rel);
2388 :
2389 16 : tupdesc = rel->rd_att;
2390 16 : natts = tupdesc->natts;
2391 :
2392 : /*
2393 : * Build sql statement to look up tuple of interest, ie, the one matching
2394 : * src_pkattvals. We used to use "SELECT *" here, but it's simpler to
2395 : * generate a result tuple that matches the table's physical structure,
2396 : * with NULLs for any dropped columns. Otherwise we have to deal with two
2397 : * different tupdescs and everything's very confusing.
2398 : */
2399 16 : appendStringInfoString(&buf, "SELECT ");
2400 :
2401 76 : for (i = 0; i < natts; i++)
2402 : {
2403 60 : Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
2404 :
2405 60 : if (i > 0)
2406 44 : appendStringInfoString(&buf, ", ");
2407 :
2408 60 : if (attr->attisdropped)
2409 8 : appendStringInfoString(&buf, "NULL");
2410 : else
2411 52 : appendStringInfoString(&buf,
2412 52 : quote_ident_cstr(NameStr(attr->attname)));
2413 : }
2414 :
2415 16 : appendStringInfo(&buf, " FROM %s WHERE ", relname);
2416 :
2417 44 : for (i = 0; i < pknumatts; i++)
2418 : {
2419 28 : int pkattnum = pkattnums[i];
2420 28 : Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2421 :
2422 28 : if (i > 0)
2423 12 : appendStringInfoString(&buf, " AND ");
2424 :
2425 28 : appendStringInfoString(&buf,
2426 28 : quote_ident_cstr(NameStr(attr->attname)));
2427 :
2428 28 : if (src_pkattvals[i] != NULL)
2429 28 : appendStringInfo(&buf, " = %s",
2430 28 : quote_literal_cstr(src_pkattvals[i]));
2431 : else
2432 0 : appendStringInfoString(&buf, " IS NULL");
2433 : }
2434 :
2435 : /*
2436 : * Retrieve the desired tuple
2437 : */
2438 16 : ret = SPI_exec(buf.data, 0);
2439 16 : pfree(buf.data);
2440 :
2441 : /*
2442 : * Only allow one qualifying tuple
2443 : */
2444 16 : if ((ret == SPI_OK_SELECT) && (SPI_processed > 1))
2445 0 : ereport(ERROR,
2446 : (errcode(ERRCODE_CARDINALITY_VIOLATION),
2447 : errmsg("source criteria matched more than one record")));
2448 :
2449 16 : else if (ret == SPI_OK_SELECT && SPI_processed == 1)
2450 : {
2451 16 : SPITupleTable *tuptable = SPI_tuptable;
2452 :
2453 16 : tuple = SPI_copytuple(tuptable->vals[0]);
2454 16 : SPI_finish();
2455 :
2456 16 : return tuple;
2457 : }
2458 : else
2459 : {
2460 : /*
2461 : * no qualifying tuples
2462 : */
2463 0 : SPI_finish();
2464 :
2465 0 : return NULL;
2466 : }
2467 :
2468 : /*
2469 : * never reached, but keep compiler quiet
2470 : */
2471 : return NULL;
2472 : }
2473 :
2474 : /*
2475 : * Open the relation named by relname_text, acquire specified type of lock,
2476 : * verify we have specified permissions.
2477 : * Caller must close rel when done with it.
2478 : */
2479 : static Relation
2480 42 : get_rel_from_relname(text *relname_text, LOCKMODE lockmode, AclMode aclmode)
2481 : {
2482 : RangeVar *relvar;
2483 : Relation rel;
2484 : AclResult aclresult;
2485 :
2486 42 : relvar = makeRangeVarFromNameList(textToQualifiedNameList(relname_text));
2487 42 : rel = table_openrv(relvar, lockmode);
2488 :
2489 42 : aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
2490 : aclmode);
2491 42 : if (aclresult != ACLCHECK_OK)
2492 0 : aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
2493 0 : RelationGetRelationName(rel));
2494 :
2495 42 : return rel;
2496 : }
2497 :
2498 : /*
2499 : * generate_relation_name - copied from ruleutils.c
2500 : * Compute the name to display for a relation
2501 : *
2502 : * The result includes all necessary quoting and schema-prefixing.
2503 : */
2504 : static char *
2505 40 : generate_relation_name(Relation rel)
2506 : {
2507 : char *nspname;
2508 : char *result;
2509 :
2510 : /* Qualify the name if not visible in search path */
2511 40 : if (RelationIsVisible(RelationGetRelid(rel)))
2512 30 : nspname = NULL;
2513 : else
2514 10 : nspname = get_namespace_name(rel->rd_rel->relnamespace);
2515 :
2516 40 : result = quote_qualified_identifier(nspname, RelationGetRelationName(rel));
2517 :
2518 40 : return result;
2519 : }
2520 :
2521 :
2522 : static remoteConn *
2523 150 : getConnectionByName(const char *name)
2524 : {
2525 : remoteConnHashEnt *hentry;
2526 : char *key;
2527 :
2528 150 : if (!remoteConnHash)
2529 4 : remoteConnHash = createConnHash();
2530 :
2531 150 : key = pstrdup(name);
2532 150 : truncate_identifier(key, strlen(key), false);
2533 150 : hentry = (remoteConnHashEnt *) hash_search(remoteConnHash,
2534 : key, HASH_FIND, NULL);
2535 :
2536 150 : if (hentry)
2537 136 : return hentry->rconn;
2538 :
2539 14 : return NULL;
2540 : }
2541 :
2542 : static HTAB *
2543 6 : createConnHash(void)
2544 : {
2545 : HASHCTL ctl;
2546 :
2547 6 : ctl.keysize = NAMEDATALEN;
2548 6 : ctl.entrysize = sizeof(remoteConnHashEnt);
2549 :
2550 6 : return hash_create("Remote Con hash", NUMCONN, &ctl,
2551 : HASH_ELEM | HASH_STRINGS);
2552 : }
2553 :
2554 : static void
2555 20 : createNewConnection(const char *name, remoteConn *rconn)
2556 : {
2557 : remoteConnHashEnt *hentry;
2558 : bool found;
2559 : char *key;
2560 :
2561 20 : if (!remoteConnHash)
2562 2 : remoteConnHash = createConnHash();
2563 :
2564 20 : key = pstrdup(name);
2565 20 : truncate_identifier(key, strlen(key), true);
2566 20 : hentry = (remoteConnHashEnt *) hash_search(remoteConnHash, key,
2567 : HASH_ENTER, &found);
2568 :
2569 20 : if (found)
2570 : {
2571 2 : libpqsrv_disconnect(rconn->conn);
2572 2 : pfree(rconn);
2573 :
2574 2 : ereport(ERROR,
2575 : (errcode(ERRCODE_DUPLICATE_OBJECT),
2576 : errmsg("duplicate connection name")));
2577 : }
2578 :
2579 18 : hentry->rconn = rconn;
2580 18 : }
2581 :
2582 : static void
2583 16 : deleteConnection(const char *name)
2584 : {
2585 : remoteConnHashEnt *hentry;
2586 : bool found;
2587 : char *key;
2588 :
2589 16 : if (!remoteConnHash)
2590 0 : remoteConnHash = createConnHash();
2591 :
2592 16 : key = pstrdup(name);
2593 16 : truncate_identifier(key, strlen(key), false);
2594 16 : hentry = (remoteConnHashEnt *) hash_search(remoteConnHash,
2595 : key, HASH_REMOVE, &found);
2596 :
2597 16 : if (!hentry)
2598 0 : ereport(ERROR,
2599 : (errcode(ERRCODE_UNDEFINED_OBJECT),
2600 : errmsg("undefined connection name")));
2601 16 : }
2602 :
2603 : /*
2604 : * We need to make sure that the connection made used credentials
2605 : * which were provided by the user, so check what credentials were
2606 : * used to connect and then make sure that they came from the user.
2607 : */
2608 : static void
2609 38 : dblink_security_check(PGconn *conn, remoteConn *rconn, const char *connstr)
2610 : {
2611 : /* Superuser bypasses security check */
2612 38 : if (superuser())
2613 38 : return;
2614 :
2615 : /* If password was used to connect, make sure it was one provided */
2616 0 : if (PQconnectionUsedPassword(conn) && dblink_connstr_has_pw(connstr))
2617 0 : return;
2618 :
2619 : #ifdef ENABLE_GSS
2620 : /* If GSSAPI creds used to connect, make sure it was one delegated */
2621 : if (PQconnectionUsedGSSAPI(conn) && be_gssapi_get_delegation(MyProcPort))
2622 : return;
2623 : #endif
2624 :
2625 : /* Otherwise, fail out */
2626 0 : libpqsrv_disconnect(conn);
2627 0 : if (rconn)
2628 0 : pfree(rconn);
2629 :
2630 0 : ereport(ERROR,
2631 : (errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
2632 : errmsg("password or GSSAPI delegated credentials required"),
2633 : errdetail("Non-superusers may only connect using credentials they provide, eg: password in connection string or delegated GSSAPI credentials"),
2634 : errhint("Ensure provided credentials match target server's authentication method.")));
2635 : }
2636 :
2637 : /*
2638 : * Function to check if the connection string includes an explicit
2639 : * password, needed to ensure that non-superuser password-based auth
2640 : * is using a provided password and not one picked up from the
2641 : * environment.
2642 : */
2643 : static bool
2644 2 : dblink_connstr_has_pw(const char *connstr)
2645 : {
2646 : PQconninfoOption *options;
2647 : PQconninfoOption *option;
2648 2 : bool connstr_gives_password = false;
2649 :
2650 2 : options = PQconninfoParse(connstr, NULL);
2651 2 : if (options)
2652 : {
2653 84 : for (option = options; option->keyword != NULL; option++)
2654 : {
2655 82 : if (strcmp(option->keyword, "password") == 0)
2656 : {
2657 2 : if (option->val != NULL && option->val[0] != '\0')
2658 : {
2659 0 : connstr_gives_password = true;
2660 0 : break;
2661 : }
2662 : }
2663 : }
2664 2 : PQconninfoFree(options);
2665 : }
2666 :
2667 2 : return connstr_gives_password;
2668 : }
2669 :
2670 : /*
2671 : * For non-superusers, insist that the connstr specify a password, except
2672 : * if GSSAPI credentials have been delegated (and we check that they are used
2673 : * for the connection in dblink_security_check later). This prevents a
2674 : * password or GSSAPI credentials from being picked up from .pgpass, a
2675 : * service file, the environment, etc. We don't want the postgres user's
2676 : * passwords or Kerberos credentials to be accessible to non-superusers.
2677 : */
2678 : static void
2679 44 : dblink_connstr_check(const char *connstr)
2680 : {
2681 44 : if (superuser())
2682 42 : return;
2683 :
2684 2 : if (dblink_connstr_has_pw(connstr))
2685 0 : return;
2686 :
2687 : #ifdef ENABLE_GSS
2688 : if (be_gssapi_get_delegation(MyProcPort))
2689 : return;
2690 : #endif
2691 :
2692 2 : ereport(ERROR,
2693 : (errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
2694 : errmsg("password or GSSAPI delegated credentials required"),
2695 : errdetail("Non-superusers must provide a password in the connection string or send delegated GSSAPI credentials.")));
2696 : }
2697 :
2698 : /*
2699 : * Report an error received from the remote server
2700 : *
2701 : * res: the received error result (will be freed)
2702 : * fail: true for ERROR ereport, false for NOTICE
2703 : * fmt and following args: sprintf-style format and values for errcontext;
2704 : * the resulting string should be worded like "while <some action>"
2705 : */
2706 : static void
2707 24 : dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
2708 : bool fail, const char *fmt,...)
2709 : {
2710 : int level;
2711 24 : char *pg_diag_sqlstate = PQresultErrorField(res, PG_DIAG_SQLSTATE);
2712 24 : char *pg_diag_message_primary = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
2713 24 : char *pg_diag_message_detail = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
2714 24 : char *pg_diag_message_hint = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
2715 24 : char *pg_diag_context = PQresultErrorField(res, PG_DIAG_CONTEXT);
2716 : int sqlstate;
2717 : char *message_primary;
2718 : char *message_detail;
2719 : char *message_hint;
2720 : char *message_context;
2721 : va_list ap;
2722 : char dblink_context_msg[512];
2723 :
2724 24 : if (fail)
2725 6 : level = ERROR;
2726 : else
2727 18 : level = NOTICE;
2728 :
2729 24 : if (pg_diag_sqlstate)
2730 24 : sqlstate = MAKE_SQLSTATE(pg_diag_sqlstate[0],
2731 : pg_diag_sqlstate[1],
2732 : pg_diag_sqlstate[2],
2733 : pg_diag_sqlstate[3],
2734 : pg_diag_sqlstate[4]);
2735 : else
2736 0 : sqlstate = ERRCODE_CONNECTION_FAILURE;
2737 :
2738 24 : message_primary = xpstrdup(pg_diag_message_primary);
2739 24 : message_detail = xpstrdup(pg_diag_message_detail);
2740 24 : message_hint = xpstrdup(pg_diag_message_hint);
2741 24 : message_context = xpstrdup(pg_diag_context);
2742 :
2743 : /*
2744 : * If we don't get a message from the PGresult, try the PGconn. This is
2745 : * needed because for connection-level failures, PQgetResult may just
2746 : * return NULL, not a PGresult at all.
2747 : */
2748 24 : if (message_primary == NULL)
2749 0 : message_primary = pchomp(PQerrorMessage(conn));
2750 :
2751 : /*
2752 : * Now that we've copied all the data we need out of the PGresult, it's
2753 : * safe to free it. We must do this to avoid PGresult leakage. We're
2754 : * leaking all the strings too, but those are in palloc'd memory that will
2755 : * get cleaned up eventually.
2756 : */
2757 24 : PQclear(res);
2758 :
2759 : /*
2760 : * Format the basic errcontext string. Below, we'll add on something
2761 : * about the connection name. That's a violation of the translatability
2762 : * guidelines about constructing error messages out of parts, but since
2763 : * there's no translation support for dblink, there's no need to worry
2764 : * about that (yet).
2765 : */
2766 24 : va_start(ap, fmt);
2767 24 : vsnprintf(dblink_context_msg, sizeof(dblink_context_msg), fmt, ap);
2768 24 : va_end(ap);
2769 :
2770 24 : ereport(level,
2771 : (errcode(sqlstate),
2772 : (message_primary != NULL && message_primary[0] != '\0') ?
2773 : errmsg_internal("%s", message_primary) :
2774 : errmsg("could not obtain message string for remote error"),
2775 : message_detail ? errdetail_internal("%s", message_detail) : 0,
2776 : message_hint ? errhint("%s", message_hint) : 0,
2777 : message_context ? (errcontext("%s", message_context)) : 0,
2778 : conname ?
2779 : (errcontext("%s on dblink connection named \"%s\"",
2780 : dblink_context_msg, conname)) :
2781 : (errcontext("%s on unnamed dblink connection",
2782 : dblink_context_msg))));
2783 18 : }
2784 :
2785 : /*
2786 : * Obtain connection string for a foreign server
2787 : */
2788 : static char *
2789 44 : get_connect_string(const char *servername)
2790 : {
2791 44 : ForeignServer *foreign_server = NULL;
2792 : UserMapping *user_mapping;
2793 : ListCell *cell;
2794 : StringInfoData buf;
2795 : ForeignDataWrapper *fdw;
2796 : AclResult aclresult;
2797 : char *srvname;
2798 :
2799 : static const PQconninfoOption *options = NULL;
2800 :
2801 44 : initStringInfo(&buf);
2802 :
2803 : /*
2804 : * Get list of valid libpq options.
2805 : *
2806 : * To avoid unnecessary work, we get the list once and use it throughout
2807 : * the lifetime of this backend process. We don't need to care about
2808 : * memory context issues, because PQconndefaults allocates with malloc.
2809 : */
2810 44 : if (!options)
2811 : {
2812 6 : options = PQconndefaults();
2813 6 : if (!options) /* assume reason for failure is OOM */
2814 0 : ereport(ERROR,
2815 : (errcode(ERRCODE_FDW_OUT_OF_MEMORY),
2816 : errmsg("out of memory"),
2817 : errdetail("Could not get libpq's default connection options.")));
2818 : }
2819 :
2820 : /* first gather the server connstr options */
2821 44 : srvname = pstrdup(servername);
2822 44 : truncate_identifier(srvname, strlen(srvname), false);
2823 44 : foreign_server = GetForeignServerByName(srvname, true);
2824 :
2825 44 : if (foreign_server)
2826 : {
2827 4 : Oid serverid = foreign_server->serverid;
2828 4 : Oid fdwid = foreign_server->fdwid;
2829 4 : Oid userid = GetUserId();
2830 :
2831 4 : user_mapping = GetUserMapping(userid, serverid);
2832 4 : fdw = GetForeignDataWrapper(fdwid);
2833 :
2834 : /* Check permissions, user must have usage on the server. */
2835 4 : aclresult = object_aclcheck(ForeignServerRelationId, serverid, userid, ACL_USAGE);
2836 4 : if (aclresult != ACLCHECK_OK)
2837 0 : aclcheck_error(aclresult, OBJECT_FOREIGN_SERVER, foreign_server->servername);
2838 :
2839 4 : foreach(cell, fdw->options)
2840 : {
2841 0 : DefElem *def = lfirst(cell);
2842 :
2843 0 : if (is_valid_dblink_option(options, def->defname, ForeignDataWrapperRelationId))
2844 0 : appendStringInfo(&buf, "%s='%s' ", def->defname,
2845 0 : escape_param_str(strVal(def->arg)));
2846 : }
2847 :
2848 12 : foreach(cell, foreign_server->options)
2849 : {
2850 8 : DefElem *def = lfirst(cell);
2851 :
2852 8 : if (is_valid_dblink_option(options, def->defname, ForeignServerRelationId))
2853 8 : appendStringInfo(&buf, "%s='%s' ", def->defname,
2854 8 : escape_param_str(strVal(def->arg)));
2855 : }
2856 :
2857 8 : foreach(cell, user_mapping->options)
2858 : {
2859 :
2860 4 : DefElem *def = lfirst(cell);
2861 :
2862 4 : if (is_valid_dblink_option(options, def->defname, UserMappingRelationId))
2863 4 : appendStringInfo(&buf, "%s='%s' ", def->defname,
2864 4 : escape_param_str(strVal(def->arg)));
2865 : }
2866 :
2867 4 : return buf.data;
2868 : }
2869 : else
2870 40 : return NULL;
2871 : }
2872 :
2873 : /*
2874 : * Escaping libpq connect parameter strings.
2875 : *
2876 : * Replaces "'" with "\'" and "\" with "\\".
2877 : */
2878 : static char *
2879 12 : escape_param_str(const char *str)
2880 : {
2881 : const char *cp;
2882 : StringInfoData buf;
2883 :
2884 12 : initStringInfo(&buf);
2885 :
2886 136 : for (cp = str; *cp; cp++)
2887 : {
2888 124 : if (*cp == '\\' || *cp == '\'')
2889 0 : appendStringInfoChar(&buf, '\\');
2890 124 : appendStringInfoChar(&buf, *cp);
2891 : }
2892 :
2893 12 : return buf.data;
2894 : }
2895 :
2896 : /*
2897 : * Validate the PK-attnums argument for dblink_build_sql_insert() and related
2898 : * functions, and translate to the internal representation.
2899 : *
2900 : * The user supplies an int2vector of 1-based logical attnums, plus a count
2901 : * argument (the need for the separate count argument is historical, but we
2902 : * still check it). We check that each attnum corresponds to a valid,
2903 : * non-dropped attribute of the rel. We do *not* prevent attnums from being
2904 : * listed twice, though the actual use-case for such things is dubious.
2905 : * Note that before Postgres 9.0, the user's attnums were interpreted as
2906 : * physical not logical column numbers; this was changed for future-proofing.
2907 : *
2908 : * The internal representation is a palloc'd int array of 0-based physical
2909 : * attnums.
2910 : */
2911 : static void
2912 36 : validate_pkattnums(Relation rel,
2913 : int2vector *pkattnums_arg, int32 pknumatts_arg,
2914 : int **pkattnums, int *pknumatts)
2915 : {
2916 36 : TupleDesc tupdesc = rel->rd_att;
2917 36 : int natts = tupdesc->natts;
2918 : int i;
2919 :
2920 : /* Don't take more array elements than there are */
2921 36 : pknumatts_arg = Min(pknumatts_arg, pkattnums_arg->dim1);
2922 :
2923 : /* Must have at least one pk attnum selected */
2924 36 : if (pknumatts_arg <= 0)
2925 0 : ereport(ERROR,
2926 : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2927 : errmsg("number of key attributes must be > 0")));
2928 :
2929 : /* Allocate output array */
2930 36 : *pkattnums = palloc_array(int, pknumatts_arg);
2931 36 : *pknumatts = pknumatts_arg;
2932 :
2933 : /* Validate attnums and convert to internal form */
2934 114 : for (i = 0; i < pknumatts_arg; i++)
2935 : {
2936 90 : int pkattnum = pkattnums_arg->values[i];
2937 : int lnum;
2938 : int j;
2939 :
2940 : /* Can throw error immediately if out of range */
2941 90 : if (pkattnum <= 0 || pkattnum > natts)
2942 12 : ereport(ERROR,
2943 : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2944 : errmsg("invalid attribute number %d", pkattnum)));
2945 :
2946 : /* Identify which physical column has this logical number */
2947 78 : lnum = 0;
2948 138 : for (j = 0; j < natts; j++)
2949 : {
2950 : /* dropped columns don't count */
2951 138 : if (TupleDescAttr(tupdesc, j)->attisdropped)
2952 6 : continue;
2953 :
2954 132 : if (++lnum == pkattnum)
2955 78 : break;
2956 : }
2957 :
2958 78 : if (j < natts)
2959 78 : (*pkattnums)[i] = j;
2960 : else
2961 0 : ereport(ERROR,
2962 : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2963 : errmsg("invalid attribute number %d", pkattnum)));
2964 : }
2965 24 : }
2966 :
2967 : /*
2968 : * Check if the specified connection option is valid.
2969 : *
2970 : * We basically allow whatever libpq thinks is an option, with these
2971 : * restrictions:
2972 : * debug options: disallowed
2973 : * "client_encoding": disallowed
2974 : * "user": valid only in USER MAPPING options
2975 : * secure options (eg password): valid only in USER MAPPING options
2976 : * others: valid only in FOREIGN SERVER options
2977 : *
2978 : * We disallow client_encoding because it would be overridden anyway via
2979 : * PQclientEncoding; allowing it to be specified would merely promote
2980 : * confusion.
2981 : */
2982 : static bool
2983 186 : is_valid_dblink_option(const PQconninfoOption *options, const char *option,
2984 : Oid context)
2985 : {
2986 : const PQconninfoOption *opt;
2987 :
2988 : /* Look up the option in libpq result */
2989 3726 : for (opt = options; opt->keyword; opt++)
2990 : {
2991 3722 : if (strcmp(opt->keyword, option) == 0)
2992 182 : break;
2993 : }
2994 186 : if (opt->keyword == NULL)
2995 4 : return false;
2996 :
2997 : /* Disallow debug options (particularly "replication") */
2998 182 : if (strchr(opt->dispchar, 'D'))
2999 4 : return false;
3000 :
3001 : /* Disallow "client_encoding" */
3002 178 : if (strcmp(opt->keyword, "client_encoding") == 0)
3003 4 : return false;
3004 :
3005 : /*
3006 : * If the option is "user" or marked secure, it should be specified only
3007 : * in USER MAPPING. Others should be specified only in SERVER.
3008 : */
3009 174 : if (strcmp(opt->keyword, "user") == 0 || strchr(opt->dispchar, '*'))
3010 : {
3011 18 : if (context != UserMappingRelationId)
3012 6 : return false;
3013 : }
3014 : else
3015 : {
3016 156 : if (context != ForeignServerRelationId)
3017 144 : return false;
3018 : }
3019 :
3020 24 : return true;
3021 : }
3022 :
3023 : /*
3024 : * Copy the remote session's values of GUCs that affect datatype I/O
3025 : * and apply them locally in a new GUC nesting level. Returns the new
3026 : * nestlevel (which is needed by restoreLocalGucs to undo the settings),
3027 : * or -1 if no new nestlevel was needed.
3028 : *
3029 : * We use the equivalent of a function SET option to allow the settings to
3030 : * persist only until the caller calls restoreLocalGucs. If an error is
3031 : * thrown in between, guc.c will take care of undoing the settings.
3032 : */
3033 : static int
3034 64 : applyRemoteGucs(PGconn *conn)
3035 : {
3036 : static const char *const GUCsAffectingIO[] = {
3037 : "DateStyle",
3038 : "IntervalStyle"
3039 : };
3040 :
3041 64 : int nestlevel = -1;
3042 : int i;
3043 :
3044 192 : for (i = 0; i < lengthof(GUCsAffectingIO); i++)
3045 : {
3046 128 : const char *gucName = GUCsAffectingIO[i];
3047 128 : const char *remoteVal = PQparameterStatus(conn, gucName);
3048 : const char *localVal;
3049 :
3050 : /*
3051 : * If the remote server is pre-8.4, it won't have IntervalStyle, but
3052 : * that's okay because its output format won't be ambiguous. So just
3053 : * skip the GUC if we don't get a value for it. (We might eventually
3054 : * need more complicated logic with remote-version checks here.)
3055 : */
3056 128 : if (remoteVal == NULL)
3057 0 : continue;
3058 :
3059 : /*
3060 : * Avoid GUC-setting overhead if the remote and local GUCs already
3061 : * have the same value.
3062 : */
3063 128 : localVal = GetConfigOption(gucName, false, false);
3064 : Assert(localVal != NULL);
3065 :
3066 128 : if (strcmp(remoteVal, localVal) == 0)
3067 94 : continue;
3068 :
3069 : /* Create new GUC nest level if we didn't already */
3070 34 : if (nestlevel < 0)
3071 18 : nestlevel = NewGUCNestLevel();
3072 :
3073 : /* Apply the option (this will throw error on failure) */
3074 34 : (void) set_config_option(gucName, remoteVal,
3075 : PGC_USERSET, PGC_S_SESSION,
3076 : GUC_ACTION_SAVE, true, 0, false);
3077 : }
3078 :
3079 64 : return nestlevel;
3080 : }
3081 :
3082 : /*
3083 : * Restore local GUCs after they have been overlaid with remote settings.
3084 : */
3085 : static void
3086 66 : restoreLocalGucs(int nestlevel)
3087 : {
3088 : /* Do nothing if no new nestlevel was created */
3089 66 : if (nestlevel > 0)
3090 16 : AtEOXact_GUC(true, nestlevel);
3091 66 : }
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