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Make libpqsrv_cancel's return const char *, not char *
[pgsql.git] / contrib / dblink / dblink.c
blob755293456fff687183c969aeb9724db24af13c35
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 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 xpstrdup(const char *in)
157 {
158 if (in == NULL)
159 return NULL;
160 return pstrdup(in);
161 }
162
163 static void
164 pg_attribute_noreturn()
165 dblink_res_internalerror(PGconn *conn, PGresult *res, const char *p2)
166 {
167 char *msg = pchomp(PQerrorMessage(conn));
168
169 PQclear(res);
170 elog(ERROR, "%s: %s", p2, msg);
171 }
172
173 static void
174 pg_attribute_noreturn()
175 dblink_conn_not_avail(const char *conname)
176 {
177 if (conname)
178 ereport(ERROR,
179 (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
180 errmsg("connection \"%s\" not available", conname)));
181 else
182 ereport(ERROR,
183 (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
184 errmsg("connection not available")));
185 }
186
187 static void
188 dblink_get_conn(char *conname_or_str,
189 PGconn *volatile *conn_p, char **conname_p, volatile bool *freeconn_p)
190 {
191 remoteConn *rconn = getConnectionByName(conname_or_str);
192 PGconn *conn;
193 char *conname;
194 bool freeconn;
195
196 if (rconn)
197 {
198 conn = rconn->conn;
199 conname = conname_or_str;
200 freeconn = false;
201 }
202 else
203 {
204 const char *connstr;
205
206 connstr = get_connect_string(conname_or_str);
207 if (connstr == NULL)
208 connstr = conname_or_str;
209 dblink_connstr_check(connstr);
210
211 /* first time, allocate or get the custom wait event */
212 if (dblink_we_get_conn == 0)
213 dblink_we_get_conn = WaitEventExtensionNew("DblinkGetConnect");
214
215 /* OK to make connection */
216 conn = libpqsrv_connect(connstr, dblink_we_get_conn);
217
218 if (PQstatus(conn) == CONNECTION_BAD)
219 {
220 char *msg = pchomp(PQerrorMessage(conn));
221
222 libpqsrv_disconnect(conn);
223 ereport(ERROR,
224 (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
225 errmsg("could not establish connection"),
226 errdetail_internal("%s", msg)));
227 }
228 dblink_security_check(conn, rconn, connstr);
229 if (PQclientEncoding(conn) != GetDatabaseEncoding())
230 PQsetClientEncoding(conn, GetDatabaseEncodingName());
231 freeconn = true;
232 conname = NULL;
233 }
234
235 *conn_p = conn;
236 *conname_p = conname;
237 *freeconn_p = freeconn;
238 }
239
240 static PGconn *
241 dblink_get_named_conn(const char *conname)
242 {
243 remoteConn *rconn = getConnectionByName(conname);
244
245 if (rconn)
246 return rconn->conn;
247
248 dblink_conn_not_avail(conname);
249 return NULL; /* keep compiler quiet */
250 }
251
252 static void
253 dblink_init(void)
254 {
255 if (!pconn)
256 {
257 if (dblink_we_get_result == 0)
258 dblink_we_get_result = WaitEventExtensionNew("DblinkGetResult");
259
260 pconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext, sizeof(remoteConn));
261 pconn->conn = NULL;
262 pconn->openCursorCount = 0;
263 pconn->newXactForCursor = false;
264 }
265 }
266
267 /*
268 * Create a persistent connection to another database
269 */
270 PG_FUNCTION_INFO_V1(dblink_connect);
271 Datum
272 dblink_connect(PG_FUNCTION_ARGS)
273 {
274 char *conname_or_str = NULL;
275 char *connstr = NULL;
276 char *connname = NULL;
277 char *msg;
278 PGconn *conn = NULL;
279 remoteConn *rconn = NULL;
280
281 dblink_init();
282
283 if (PG_NARGS() == 2)
284 {
285 conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(1));
286 connname = text_to_cstring(PG_GETARG_TEXT_PP(0));
287 }
288 else if (PG_NARGS() == 1)
289 conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0));
290
291 if (connname)
292 {
293 rconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext,
294 sizeof(remoteConn));
295 rconn->conn = NULL;
296 rconn->openCursorCount = 0;
297 rconn->newXactForCursor = false;
298 }
299
300 /* first check for valid foreign data server */
301 connstr = get_connect_string(conname_or_str);
302 if (connstr == NULL)
303 connstr = conname_or_str;
304
305 /* check password in connection string if not superuser */
306 dblink_connstr_check(connstr);
307
308 /* first time, allocate or get the custom wait event */
309 if (dblink_we_connect == 0)
310 dblink_we_connect = WaitEventExtensionNew("DblinkConnect");
311
312 /* OK to make connection */
313 conn = libpqsrv_connect(connstr, dblink_we_connect);
314
315 if (PQstatus(conn) == CONNECTION_BAD)
316 {
317 msg = pchomp(PQerrorMessage(conn));
318 libpqsrv_disconnect(conn);
319 if (rconn)
320 pfree(rconn);
321
322 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 dblink_security_check(conn, rconn, connstr);
330
331 /* attempt to set client encoding to match server encoding, if needed */
332 if (PQclientEncoding(conn) != GetDatabaseEncoding())
333 PQsetClientEncoding(conn, GetDatabaseEncodingName());
334
335 if (connname)
336 {
337 rconn->conn = conn;
338 createNewConnection(connname, rconn);
339 }
340 else
341 {
342 if (pconn->conn)
343 libpqsrv_disconnect(pconn->conn);
344 pconn->conn = conn;
345 }
346
347 PG_RETURN_TEXT_P(cstring_to_text("OK"));
348 }
349
350 /*
351 * Clear a persistent connection to another database
352 */
353 PG_FUNCTION_INFO_V1(dblink_disconnect);
354 Datum
355 dblink_disconnect(PG_FUNCTION_ARGS)
356 {
357 char *conname = NULL;
358 remoteConn *rconn = NULL;
359 PGconn *conn = NULL;
360
361 dblink_init();
362
363 if (PG_NARGS() == 1)
364 {
365 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
366 rconn = getConnectionByName(conname);
367 if (rconn)
368 conn = rconn->conn;
369 }
370 else
371 conn = pconn->conn;
372
373 if (!conn)
374 dblink_conn_not_avail(conname);
375
376 libpqsrv_disconnect(conn);
377 if (rconn)
378 {
379 deleteConnection(conname);
380 pfree(rconn);
381 }
382 else
383 pconn->conn = NULL;
384
385 PG_RETURN_TEXT_P(cstring_to_text("OK"));
386 }
387
388 /*
389 * opens a cursor using a persistent connection
390 */
391 PG_FUNCTION_INFO_V1(dblink_open);
392 Datum
393 dblink_open(PG_FUNCTION_ARGS)
394 {
395 PGresult *res = NULL;
396 PGconn *conn;
397 char *curname = NULL;
398 char *sql = NULL;
399 char *conname = NULL;
400 StringInfoData buf;
401 remoteConn *rconn = NULL;
402 bool fail = true; /* default to backward compatible behavior */
403
404 dblink_init();
405 initStringInfo(&buf);
406
407 if (PG_NARGS() == 2)
408 {
409 /* text,text */
410 curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
411 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
412 rconn = pconn;
413 }
414 else if (PG_NARGS() == 3)
415 {
416 /* might be text,text,text or text,text,bool */
417 if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID)
418 {
419 curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
420 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
421 fail = PG_GETARG_BOOL(2);
422 rconn = pconn;
423 }
424 else
425 {
426 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
427 curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
428 sql = text_to_cstring(PG_GETARG_TEXT_PP(2));
429 rconn = getConnectionByName(conname);
430 }
431 }
432 else if (PG_NARGS() == 4)
433 {
434 /* text,text,text,bool */
435 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
436 curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
437 sql = text_to_cstring(PG_GETARG_TEXT_PP(2));
438 fail = PG_GETARG_BOOL(3);
439 rconn = getConnectionByName(conname);
440 }
441
442 if (!rconn || !rconn->conn)
443 dblink_conn_not_avail(conname);
444
445 conn = rconn->conn;
446
447 /* If we are not in a transaction, start one */
448 if (PQtransactionStatus(conn) == PQTRANS_IDLE)
449 {
450 res = libpqsrv_exec(conn, "BEGIN", dblink_we_get_result);
451 if (PQresultStatus(res) != PGRES_COMMAND_OK)
452 dblink_res_internalerror(conn, res, "begin error");
453 PQclear(res);
454 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 rconn->openCursorCount = 0;
462 }
463
464 /* if we started a transaction, increment cursor count */
465 if (rconn->newXactForCursor)
466 (rconn->openCursorCount)++;
467
468 appendStringInfo(&buf, "DECLARE %s CURSOR FOR %s", curname, sql);
469 res = libpqsrv_exec(conn, buf.data, dblink_we_get_result);
470 if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
471 {
472 dblink_res_error(conn, conname, res, fail,
473 "while opening cursor \"%s\"", curname);
474 PG_RETURN_TEXT_P(cstring_to_text("ERROR"));
475 }
476
477 PQclear(res);
478 PG_RETURN_TEXT_P(cstring_to_text("OK"));
479 }
480
481 /*
482 * closes a cursor
483 */
484 PG_FUNCTION_INFO_V1(dblink_close);
485 Datum
486 dblink_close(PG_FUNCTION_ARGS)
487 {
488 PGconn *conn;
489 PGresult *res = NULL;
490 char *curname = NULL;
491 char *conname = NULL;
492 StringInfoData buf;
493 remoteConn *rconn = NULL;
494 bool fail = true; /* default to backward compatible behavior */
495
496 dblink_init();
497 initStringInfo(&buf);
498
499 if (PG_NARGS() == 1)
500 {
501 /* text */
502 curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
503 rconn = pconn;
504 }
505 else if (PG_NARGS() == 2)
506 {
507 /* might be text,text or text,bool */
508 if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
509 {
510 curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
511 fail = PG_GETARG_BOOL(1);
512 rconn = pconn;
513 }
514 else
515 {
516 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
517 curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
518 rconn = getConnectionByName(conname);
519 }
520 }
521 if (PG_NARGS() == 3)
522 {
523 /* text,text,bool */
524 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
525 curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
526 fail = PG_GETARG_BOOL(2);
527 rconn = getConnectionByName(conname);
528 }
529
530 if (!rconn || !rconn->conn)
531 dblink_conn_not_avail(conname);
532
533 conn = rconn->conn;
534
535 appendStringInfo(&buf, "CLOSE %s", curname);
536
537 /* close the cursor */
538 res = libpqsrv_exec(conn, buf.data, dblink_we_get_result);
539 if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
540 {
541 dblink_res_error(conn, conname, res, fail,
542 "while closing cursor \"%s\"", curname);
543 PG_RETURN_TEXT_P(cstring_to_text("ERROR"));
544 }
545
546 PQclear(res);
547
548 /* if we started a transaction, decrement cursor count */
549 if (rconn->newXactForCursor)
550 {
551 (rconn->openCursorCount)--;
552
553 /* if count is zero, commit the transaction */
554 if (rconn->openCursorCount == 0)
555 {
556 rconn->newXactForCursor = false;
557
558 res = libpqsrv_exec(conn, "COMMIT", dblink_we_get_result);
559 if (PQresultStatus(res) != PGRES_COMMAND_OK)
560 dblink_res_internalerror(conn, res, "commit error");
561 PQclear(res);
562 }
563 }
564
565 PG_RETURN_TEXT_P(cstring_to_text("OK"));
566 }
567
568 /*
569 * Fetch results from an open cursor
570 */
571 PG_FUNCTION_INFO_V1(dblink_fetch);
572 Datum
573 dblink_fetch(PG_FUNCTION_ARGS)
574 {
575 PGresult *res = NULL;
576 char *conname = NULL;
577 remoteConn *rconn = NULL;
578 PGconn *conn = NULL;
579 StringInfoData buf;
580 char *curname = NULL;
581 int howmany = 0;
582 bool fail = true; /* default to backward compatible */
583
584 prepTuplestoreResult(fcinfo);
585
586 dblink_init();
587
588 if (PG_NARGS() == 4)
589 {
590 /* text,text,int,bool */
591 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
592 curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
593 howmany = PG_GETARG_INT32(2);
594 fail = PG_GETARG_BOOL(3);
595
596 rconn = getConnectionByName(conname);
597 if (rconn)
598 conn = rconn->conn;
599 }
600 else if (PG_NARGS() == 3)
601 {
602 /* text,text,int or text,int,bool */
603 if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID)
604 {
605 curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
606 howmany = PG_GETARG_INT32(1);
607 fail = PG_GETARG_BOOL(2);
608 conn = pconn->conn;
609 }
610 else
611 {
612 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
613 curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
614 howmany = PG_GETARG_INT32(2);
615
616 rconn = getConnectionByName(conname);
617 if (rconn)
618 conn = rconn->conn;
619 }
620 }
621 else if (PG_NARGS() == 2)
622 {
623 /* text,int */
624 curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
625 howmany = PG_GETARG_INT32(1);
626 conn = pconn->conn;
627 }
628
629 if (!conn)
630 dblink_conn_not_avail(conname);
631
632 initStringInfo(&buf);
633 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 res = libpqsrv_exec(conn, buf.data, dblink_we_get_result);
641 if (!res ||
642 (PQresultStatus(res) != PGRES_COMMAND_OK &&
643 PQresultStatus(res) != PGRES_TUPLES_OK))
644 {
645 dblink_res_error(conn, conname, res, fail,
646 "while fetching from cursor \"%s\"", curname);
647 return (Datum) 0;
648 }
649 else if (PQresultStatus(res) == PGRES_COMMAND_OK)
650 {
651 /* cursor does not exist - closed already or bad name */
652 PQclear(res);
653 ereport(ERROR,
654 (errcode(ERRCODE_INVALID_CURSOR_NAME),
655 errmsg("cursor \"%s\" does not exist", curname)));
656 }
657
658 materializeResult(fcinfo, conn, res);
659 return (Datum) 0;
660 }
661
662 /*
663 * Note: this is the new preferred version of dblink
664 */
665 PG_FUNCTION_INFO_V1(dblink_record);
666 Datum
667 dblink_record(PG_FUNCTION_ARGS)
668 {
669 return dblink_record_internal(fcinfo, false);
670 }
671
672 PG_FUNCTION_INFO_V1(dblink_send_query);
673 Datum
674 dblink_send_query(PG_FUNCTION_ARGS)
675 {
676 PGconn *conn;
677 char *sql;
678 int retval;
679
680 if (PG_NARGS() == 2)
681 {
682 conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
683 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
684 }
685 else
686 /* shouldn't happen */
687 elog(ERROR, "wrong number of arguments");
688
689 /* async query send */
690 retval = PQsendQuery(conn, sql);
691 if (retval != 1)
692 elog(NOTICE, "could not send query: %s", pchomp(PQerrorMessage(conn)));
693
694 PG_RETURN_INT32(retval);
695 }
696
697 PG_FUNCTION_INFO_V1(dblink_get_result);
698 Datum
699 dblink_get_result(PG_FUNCTION_ARGS)
700 {
701 return dblink_record_internal(fcinfo, true);
702 }
703
704 static Datum
705 dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
706 {
707 PGconn *volatile conn = NULL;
708 volatile bool freeconn = false;
709
710 prepTuplestoreResult(fcinfo);
711
712 dblink_init();
713
714 PG_TRY();
715 {
716 char *sql = NULL;
717 char *conname = NULL;
718 bool fail = true; /* default to backward compatible */
719
720 if (!is_async)
721 {
722 if (PG_NARGS() == 3)
723 {
724 /* text,text,bool */
725 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
726 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
727 fail = PG_GETARG_BOOL(2);
728 dblink_get_conn(conname, &conn, &conname, &freeconn);
729 }
730 else if (PG_NARGS() == 2)
731 {
732 /* text,text or text,bool */
733 if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
734 {
735 sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
736 fail = PG_GETARG_BOOL(1);
737 conn = pconn->conn;
738 }
739 else
740 {
741 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
742 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
743 dblink_get_conn(conname, &conn, &conname, &freeconn);
744 }
745 }
746 else if (PG_NARGS() == 1)
747 {
748 /* text */
749 conn = pconn->conn;
750 sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
751 }
752 else
753 /* shouldn't happen */
754 elog(ERROR, "wrong number of arguments");
755 }
756 else /* is_async */
757 {
758 /* get async result */
759 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
760
761 if (PG_NARGS() == 2)
762 {
763 /* text,bool */
764 fail = PG_GETARG_BOOL(1);
765 conn = dblink_get_named_conn(conname);
766 }
767 else if (PG_NARGS() == 1)
768 {
769 /* text */
770 conn = dblink_get_named_conn(conname);
771 }
772 else
773 /* shouldn't happen */
774 elog(ERROR, "wrong number of arguments");
775 }
776
777 if (!conn)
778 dblink_conn_not_avail(conname);
779
780 if (!is_async)
781 {
782 /* synchronous query, use efficient tuple collection method */
783 materializeQueryResult(fcinfo, conn, conname, sql, fail);
784 }
785 else
786 {
787 /* async result retrieval, do it the old way */
788 PGresult *res = libpqsrv_get_result(conn, dblink_we_get_result);
789
790 /* NULL means we're all done with the async results */
791 if (res)
792 {
793 if (PQresultStatus(res) != PGRES_COMMAND_OK &&
794 PQresultStatus(res) != PGRES_TUPLES_OK)
795 {
796 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 materializeResult(fcinfo, conn, res);
803 }
804 }
805 }
806 }
807 PG_FINALLY();
808 {
809 /* if needed, close the connection to the database */
810 if (freeconn)
811 libpqsrv_disconnect(conn);
812 }
813 PG_END_TRY();
814
815 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 prepTuplestoreResult(FunctionCallInfo fcinfo)
826 {
827 ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
828
829 /* check to see if query supports us returning a tuplestore */
830 if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
831 ereport(ERROR,
832 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
833 errmsg("set-valued function called in context that cannot accept a set")));
834 if (!(rsinfo->allowedModes & SFRM_Materialize))
835 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 rsinfo->returnMode = SFRM_Materialize;
841
842 /* caller must fill these to return a non-empty result */
843 rsinfo->setResult = NULL;
844 rsinfo->setDesc = NULL;
845 }
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 materializeResult(FunctionCallInfo fcinfo, PGconn *conn, PGresult *res)
854 {
855 ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
856
857 /* prepTuplestoreResult must have been called previously */
858 Assert(rsinfo->returnMode == SFRM_Materialize);
859
860 PG_TRY();
861 {
862 TupleDesc tupdesc;
863 bool is_sql_cmd;
864 int ntuples;
865 int nfields;
866
867 if (PQresultStatus(res) == PGRES_COMMAND_OK)
868 {
869 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 tupdesc = CreateTemplateTupleDesc(1);
876 TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
877 TEXTOID, -1, 0);
878 ntuples = 1;
879 nfields = 1;
880 }
881 else
882 {
883 Assert(PQresultStatus(res) == PGRES_TUPLES_OK);
884
885 is_sql_cmd = false;
886
887 /* get a tuple descriptor for our result type */
888 switch (get_call_result_type(fcinfo, NULL, &tupdesc))
889 {
890 case TYPEFUNC_COMPOSITE:
891 /* success */
892 break;
893 case TYPEFUNC_RECORD:
894 /* failed to determine actual type of RECORD */
895 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 default:
901 /* result type isn't composite */
902 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 tupdesc = CreateTupleDescCopy(tupdesc);
908 ntuples = PQntuples(res);
909 nfields = PQnfields(res);
910 }
911
912 /*
913 * check result and tuple descriptor have the same number of columns
914 */
915 if (nfields != tupdesc->natts)
916 ereport(ERROR,
917 (errcode(ERRCODE_DATATYPE_MISMATCH),
918 errmsg("remote query result rowtype does not match "
919 "the specified FROM clause rowtype")));
920
921 if (ntuples > 0)
922 {
923 AttInMetadata *attinmeta;
924 int nestlevel = -1;
925 Tuplestorestate *tupstore;
926 MemoryContext oldcontext;
927 int row;
928 char **values;
929
930 attinmeta = TupleDescGetAttInMetadata(tupdesc);
931
932 /* Set GUCs to ensure we read GUC-sensitive data types correctly */
933 if (!is_sql_cmd)
934 nestlevel = applyRemoteGucs(conn);
935
936 oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
937 tupstore = tuplestore_begin_heap(true, false, work_mem);
938 rsinfo->setResult = tupstore;
939 rsinfo->setDesc = tupdesc;
940 MemoryContextSwitchTo(oldcontext);
941
942 values = palloc_array(char *, nfields);
943
944 /* put all tuples into the tuplestore */
945 for (row = 0; row < ntuples; row++)
946 {
947 HeapTuple tuple;
948
949 if (!is_sql_cmd)
950 {
951 int i;
952
953 for (i = 0; i < nfields; i++)
954 {
955 if (PQgetisnull(res, row, i))
956 values[i] = NULL;
957 else
958 values[i] = PQgetvalue(res, row, i);
959 }
960 }
961 else
962 {
963 values[0] = PQcmdStatus(res);
964 }
965
966 /* build the tuple and put it into the tuplestore. */
967 tuple = BuildTupleFromCStrings(attinmeta, values);
968 tuplestore_puttuple(tupstore, tuple);
969 }
970
971 /* clean up GUC settings, if we changed any */
972 restoreLocalGucs(nestlevel);
973 }
974 }
975 PG_FINALLY();
976 {
977 /* be sure to release the libpq result */
978 PQclear(res);
979 }
980 PG_END_TRY();
981 }
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 materializeQueryResult(FunctionCallInfo fcinfo,
993 PGconn *conn,
994 const char *conname,
995 const char *sql,
996 bool fail)
997 {
998 ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
999 PGresult *volatile res = NULL;
1000 volatile storeInfo sinfo = {0};
1001
1002 /* prepTuplestoreResult must have been called previously */
1003 Assert(rsinfo->returnMode == SFRM_Materialize);
1004
1005 sinfo.fcinfo = fcinfo;
1006
1007 PG_TRY();
1008 {
1009 /* Create short-lived memory context for data conversions */
1010 sinfo.tmpcontext = AllocSetContextCreate(CurrentMemoryContext,
1011 "dblink temporary context",
1012 ALLOCSET_DEFAULT_SIZES);
1013
1014 /* execute query, collecting any tuples into the tuplestore */
1015 res = storeQueryResult(&sinfo, conn, sql);
1016
1017 if (!res ||
1018 (PQresultStatus(res) != PGRES_COMMAND_OK &&
1019 PQresultStatus(res) != PGRES_TUPLES_OK))
1020 {
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 PGresult *res1 = res;
1026
1027 res = NULL;
1028 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 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 tupdesc = CreateTemplateTupleDesc(1);
1050 TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
1051 TEXTOID, -1, 0);
1052 attinmeta = TupleDescGetAttInMetadata(tupdesc);
1053
1054 oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
1055 tupstore = tuplestore_begin_heap(true, false, work_mem);
1056 rsinfo->setResult = tupstore;
1057 rsinfo->setDesc = tupdesc;
1058 MemoryContextSwitchTo(oldcontext);
1059
1060 values[0] = PQcmdStatus(res);
1061
1062 /* build the tuple and put it into the tuplestore. */
1063 tuple = BuildTupleFromCStrings(attinmeta, values);
1064 tuplestore_puttuple(tupstore, tuple);
1065
1066 PQclear(res);
1067 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 PQclear(res);
1076 res = NULL;
1077 }
1078
1079 /* clean up data conversion short-lived memory context */
1080 if (sinfo.tmpcontext != NULL)
1081 MemoryContextDelete(sinfo.tmpcontext);
1082 sinfo.tmpcontext = NULL;
1083
1084 PQclear(sinfo.last_res);
1085 sinfo.last_res = NULL;
1086 PQclear(sinfo.cur_res);
1087 sinfo.cur_res = NULL;
1088 }
1089 PG_CATCH();
1090 {
1091 /* be sure to release any libpq result we collected */
1092 PQclear(res);
1093 PQclear(sinfo.last_res);
1094 PQclear(sinfo.cur_res);
1095 /* and clear out any pending data in libpq */
1096 while ((res = libpqsrv_get_result(conn, dblink_we_get_result)) !=
1097 NULL)
1098 PQclear(res);
1099 PG_RE_THROW();
1100 }
1101 PG_END_TRY();
1102 }
1103
1104 /*
1105 * Execute query, and send any result rows to sinfo->tuplestore.
1106 */
1107 static PGresult *
1108 storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql)
1109 {
1110 bool first = true;
1111 int nestlevel = -1;
1112 PGresult *res;
1113
1114 if (!PQsendQuery(conn, sql))
1115 elog(ERROR, "could not send query: %s", pchomp(PQerrorMessage(conn)));
1116
1117 if (!PQsetSingleRowMode(conn)) /* shouldn't fail */
1118 elog(ERROR, "failed to set single-row mode for dblink query");
1119
1120 for (;;)
1121 {
1122 CHECK_FOR_INTERRUPTS();
1123
1124 sinfo->cur_res = libpqsrv_get_result(conn, dblink_we_get_result);
1125 if (!sinfo->cur_res)
1126 break;
1127
1128 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 if (first && nestlevel < 0)
1138 nestlevel = applyRemoteGucs(conn);
1139
1140 storeRow(sinfo, sinfo->cur_res, first);
1141
1142 PQclear(sinfo->cur_res);
1143 sinfo->cur_res = NULL;
1144 first = false;
1145 }
1146 else
1147 {
1148 /* if empty resultset, fill tuplestore header */
1149 if (first && PQresultStatus(sinfo->cur_res) == PGRES_TUPLES_OK)
1150 storeRow(sinfo, sinfo->cur_res, first);
1151
1152 /* store completed result at last_res */
1153 PQclear(sinfo->last_res);
1154 sinfo->last_res = sinfo->cur_res;
1155 sinfo->cur_res = NULL;
1156 first = true;
1157 }
1158 }
1159
1160 /* clean up GUC settings, if we changed any */
1161 restoreLocalGucs(nestlevel);
1162
1163 /* return last_res */
1164 res = sinfo->last_res;
1165 sinfo->last_res = NULL;
1166 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 storeRow(volatile storeInfo *sinfo, PGresult *res, bool first)
1177 {
1178 int nfields = PQnfields(res);
1179 HeapTuple tuple;
1180 int i;
1181 MemoryContext oldcontext;
1182
1183 if (first)
1184 {
1185 /* Prepare for new result set */
1186 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 if (sinfo->tuplestore)
1195 tuplestore_end(sinfo->tuplestore);
1196 sinfo->tuplestore = NULL;
1197
1198 /* get a tuple descriptor for our result type */
1199 switch (get_call_result_type(sinfo->fcinfo, NULL, &tupdesc))
1200 {
1201 case TYPEFUNC_COMPOSITE:
1202 /* success */
1203 break;
1204 case TYPEFUNC_RECORD:
1205 /* failed to determine actual type of RECORD */
1206 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 default:
1212 /* result type isn't composite */
1213 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 tupdesc = CreateTupleDescCopy(tupdesc);
1219
1220 /* check result and tuple descriptor have the same number of columns */
1221 if (nfields != tupdesc->natts)
1222 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 sinfo->attinmeta = TupleDescGetAttInMetadata(tupdesc);
1229
1230 /* Create a new, empty tuplestore */
1231 oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
1232 sinfo->tuplestore = tuplestore_begin_heap(true, false, work_mem);
1233 rsinfo->setResult = sinfo->tuplestore;
1234 rsinfo->setDesc = tupdesc;
1235 MemoryContextSwitchTo(oldcontext);
1236
1237 /* Done if empty resultset */
1238 if (PQntuples(res) == 0)
1239 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 if (sinfo->cstrs)
1246 pfree(sinfo->cstrs);
1247 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 oldcontext = MemoryContextSwitchTo(sinfo->tmpcontext);
1259
1260 /*
1261 * Fill cstrs with null-terminated strings of column values.
1262 */
1263 for (i = 0; i < nfields; i++)
1264 {
1265 if (PQgetisnull(res, 0, i))
1266 sinfo->cstrs[i] = NULL;
1267 else
1268 sinfo->cstrs[i] = PQgetvalue(res, 0, i);
1269 }
1270
1271 /* Convert row to a tuple, and add it to the tuplestore */
1272 tuple = BuildTupleFromCStrings(sinfo->attinmeta, sinfo->cstrs);
1273
1274 tuplestore_puttuple(sinfo->tuplestore, tuple);
1275
1276 /* Clean up */
1277 MemoryContextSwitchTo(oldcontext);
1278 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 PG_FUNCTION_INFO_V1(dblink_get_connections);
1287 Datum
1288 dblink_get_connections(PG_FUNCTION_ARGS)
1289 {
1290 HASH_SEQ_STATUS status;
1291 remoteConnHashEnt *hentry;
1292 ArrayBuildState *astate = NULL;
1293
1294 if (remoteConnHash)
1295 {
1296 hash_seq_init(&status, remoteConnHash);
1297 while ((hentry = (remoteConnHashEnt *) hash_seq_search(&status)) != NULL)
1298 {
1299 /* stash away current value */
1300 astate = accumArrayResult(astate,
1301 CStringGetTextDatum(hentry->name),
1302 false, TEXTOID, CurrentMemoryContext);
1303 }
1304 }
1305
1306 if (astate)
1307 PG_RETURN_DATUM(makeArrayResult(astate,
1308 CurrentMemoryContext));
1309 else
1310 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 PG_FUNCTION_INFO_V1(dblink_is_busy);
1322 Datum
1323 dblink_is_busy(PG_FUNCTION_ARGS)
1324 {
1325 PGconn *conn;
1326
1327 dblink_init();
1328 conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
1329
1330 PQconsumeInput(conn);
1331 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 PG_FUNCTION_INFO_V1(dblink_cancel_query);
1346 Datum
1347 dblink_cancel_query(PG_FUNCTION_ARGS)
1348 {
1349 PGconn *conn;
1350 const char *msg;
1351 TimestampTz endtime;
1352
1353 dblink_init();
1354 conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
1355 endtime = TimestampTzPlusMilliseconds(GetCurrentTimestamp(),
1356 30000);
1357 msg = libpqsrv_cancel(conn, endtime);
1358 if (msg == NULL)
1359 msg = "OK";
1360
1361 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 PG_FUNCTION_INFO_V1(dblink_error_message);
1376 Datum
1377 dblink_error_message(PG_FUNCTION_ARGS)
1378 {
1379 char *msg;
1380 PGconn *conn;
1381
1382 dblink_init();
1383 conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
1384
1385 msg = PQerrorMessage(conn);
1386 if (msg == NULL || msg[0] == '\0')
1387 PG_RETURN_TEXT_P(cstring_to_text("OK"));
1388 else
1389 PG_RETURN_TEXT_P(cstring_to_text(pchomp(msg)));
1390 }
1391
1392 /*
1393 * Execute an SQL non-SELECT command
1394 */
1395 PG_FUNCTION_INFO_V1(dblink_exec);
1396 Datum
1397 dblink_exec(PG_FUNCTION_ARGS)
1398 {
1399 text *volatile sql_cmd_status = NULL;
1400 PGconn *volatile conn = NULL;
1401 volatile bool freeconn = false;
1402
1403 dblink_init();
1404
1405 PG_TRY();
1406 {
1407 PGresult *res = NULL;
1408 char *sql = NULL;
1409 char *conname = NULL;
1410 bool fail = true; /* default to backward compatible behavior */
1411
1412 if (PG_NARGS() == 3)
1413 {
1414 /* must be text,text,bool */
1415 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
1416 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
1417 fail = PG_GETARG_BOOL(2);
1418 dblink_get_conn(conname, &conn, &conname, &freeconn);
1419 }
1420 else if (PG_NARGS() == 2)
1421 {
1422 /* might be text,text or text,bool */
1423 if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
1424 {
1425 sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
1426 fail = PG_GETARG_BOOL(1);
1427 conn = pconn->conn;
1428 }
1429 else
1430 {
1431 conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
1432 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
1433 dblink_get_conn(conname, &conn, &conname, &freeconn);
1434 }
1435 }
1436 else if (PG_NARGS() == 1)
1437 {
1438 /* must be single text argument */
1439 conn = pconn->conn;
1440 sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
1441 }
1442 else
1443 /* shouldn't happen */
1444 elog(ERROR, "wrong number of arguments");
1445
1446 if (!conn)
1447 dblink_conn_not_avail(conname);
1448
1449 res = libpqsrv_exec(conn, sql, dblink_we_get_result);
1450 if (!res ||
1451 (PQresultStatus(res) != PGRES_COMMAND_OK &&
1452 PQresultStatus(res) != PGRES_TUPLES_OK))
1453 {
1454 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 sql_cmd_status = cstring_to_text("ERROR");
1462 }
1463 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 sql_cmd_status = cstring_to_text(PQcmdStatus(res));
1470 PQclear(res);
1471 }
1472 else
1473 {
1474 PQclear(res);
1475 ereport(ERROR,
1476 (errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
1477 errmsg("statement returning results not allowed")));
1478 }
1479 }
1480 PG_FINALLY();
1481 {
1482 /* if needed, close the connection to the database */
1483 if (freeconn)
1484 libpqsrv_disconnect(conn);
1485 }
1486 PG_END_TRY();
1487
1488 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 PG_FUNCTION_INFO_V1(dblink_get_pkey);
1499 Datum
1500 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 if (SRF_IS_FIRSTCALL())
1512 {
1513 Relation rel;
1514 TupleDesc tupdesc;
1515
1516 /* create a function context for cross-call persistence */
1517 funcctx = SRF_FIRSTCALL_INIT();
1518
1519 /*
1520 * switch to memory context appropriate for multiple function calls
1521 */
1522 oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
1523
1524 /* open target relation */
1525 rel = get_rel_from_relname(PG_GETARG_TEXT_PP(0), AccessShareLock, ACL_SELECT);
1526
1527 /* get the array of attnums */
1528 results = get_pkey_attnames(rel, &indnkeyatts);
1529
1530 relation_close(rel, AccessShareLock);
1531
1532 /*
1533 * need a tuple descriptor representing one INT and one TEXT column
1534 */
1535 tupdesc = CreateTemplateTupleDesc(2);
1536 TupleDescInitEntry(tupdesc, (AttrNumber) 1, "position",
1537 INT4OID, -1, 0);
1538 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 attinmeta = TupleDescGetAttInMetadata(tupdesc);
1546 funcctx->attinmeta = attinmeta;
1547
1548 if ((results != NULL) && (indnkeyatts > 0))
1549 {
1550 funcctx->max_calls = indnkeyatts;
1551
1552 /* got results, keep track of them */
1553 funcctx->user_fctx = results;
1554 }
1555 else
1556 {
1557 /* fast track when no results */
1558 MemoryContextSwitchTo(oldcontext);
1559 SRF_RETURN_DONE(funcctx);
1560 }
1561
1562 MemoryContextSwitchTo(oldcontext);
1563 }
1564
1565 /* stuff done on every call of the function */
1566 funcctx = SRF_PERCALL_SETUP();
1567
1568 /*
1569 * initialize per-call variables
1570 */
1571 call_cntr = funcctx->call_cntr;
1572 max_calls = funcctx->max_calls;
1573
1574 results = (char **) funcctx->user_fctx;
1575 attinmeta = funcctx->attinmeta;
1576
1577 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 values = palloc_array(char *, 2);
1584 values[0] = psprintf("%d", call_cntr + 1);
1585 values[1] = results[call_cntr];
1586
1587 /* build the tuple */
1588 tuple = BuildTupleFromCStrings(attinmeta, values);
1589
1590 /* make the tuple into a datum */
1591 result = HeapTupleGetDatum(tuple);
1592
1593 SRF_RETURN_NEXT(funcctx, result);
1594 }
1595 else
1596 {
1597 /* do when there is no more left */
1598 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 PG_FUNCTION_INFO_V1(dblink_build_sql_insert);
1623 Datum
1624 dblink_build_sql_insert(PG_FUNCTION_ARGS)
1625 {
1626 text *relname_text = PG_GETARG_TEXT_PP(0);
1627 int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1628 int32 pknumatts_arg = PG_GETARG_INT32(2);
1629 ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
1630 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 rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1644
1645 /*
1646 * Process pkattnums argument.
1647 */
1648 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 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 if (src_nitems != pknumatts)
1661 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 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 if (tgt_nitems != pknumatts)
1675 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 sql = get_sql_insert(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
1683
1684 /*
1685 * Now we can close the relation.
1686 */
1687 relation_close(rel, AccessShareLock);
1688
1689 /*
1690 * And send it
1691 */
1692 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 PG_FUNCTION_INFO_V1(dblink_build_sql_delete);
1712 Datum
1713 dblink_build_sql_delete(PG_FUNCTION_ARGS)
1714 {
1715 text *relname_text = PG_GETARG_TEXT_PP(0);
1716 int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1717 int32 pknumatts_arg = PG_GETARG_INT32(2);
1718 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 rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1730
1731 /*
1732 * Process pkattnums argument.
1733 */
1734 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 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 if (tgt_nitems != pknumatts)
1747 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 sql = get_sql_delete(rel, pkattnums, pknumatts, tgt_pkattvals);
1755
1756 /*
1757 * Now we can close the relation.
1758 */
1759 relation_close(rel, AccessShareLock);
1760
1761 /*
1762 * And send it
1763 */
1764 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 PG_FUNCTION_INFO_V1(dblink_build_sql_update);
1788 Datum
1789 dblink_build_sql_update(PG_FUNCTION_ARGS)
1790 {
1791 text *relname_text = PG_GETARG_TEXT_PP(0);
1792 int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1793 int32 pknumatts_arg = PG_GETARG_INT32(2);
1794 ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
1795 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 rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1809
1810 /*
1811 * Process pkattnums argument.
1812 */
1813 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 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 if (src_nitems != pknumatts)
1826 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 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 if (tgt_nitems != pknumatts)
1840 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 sql = get_sql_update(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
1848
1849 /*
1850 * Now we can close the relation.
1851 */
1852 relation_close(rel, AccessShareLock);
1853
1854 /*
1855 * And send it
1856 */
1857 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 PG_FUNCTION_INFO_V1(dblink_current_query);
1867 Datum
1868 dblink_current_query(PG_FUNCTION_ARGS)
1869 {
1870 /* This is now just an alias for the built-in function current_query() */
1871 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 PG_FUNCTION_INFO_V1(dblink_get_notify);
1885 Datum
1886 dblink_get_notify(PG_FUNCTION_ARGS)
1887 {
1888 PGconn *conn;
1889 PGnotify *notify;
1890 ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
1891
1892 dblink_init();
1893 if (PG_NARGS() == 1)
1894 conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
1895 else
1896 conn = pconn->conn;
1897
1898 InitMaterializedSRF(fcinfo, 0);
1899
1900 PQconsumeInput(conn);
1901 while ((notify = PQnotifies(conn)) != NULL)
1902 {
1903 Datum values[DBLINK_NOTIFY_COLS];
1904 bool nulls[DBLINK_NOTIFY_COLS];
1905
1906 memset(values, 0, sizeof(values));
1907 memset(nulls, 0, sizeof(nulls));
1908
1909 if (notify->relname != NULL)
1910 values[0] = CStringGetTextDatum(notify->relname);
1911 else
1912 nulls[0] = true;
1913
1914 values[1] = Int32GetDatum(notify->be_pid);
1915
1916 if (notify->extra != NULL)
1917 values[2] = CStringGetTextDatum(notify->extra);
1918 else
1919 nulls[2] = true;
1920
1921 tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
1922
1923 PQfreemem(notify);
1924 PQconsumeInput(conn);
1925 }
1926
1927 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 PG_FUNCTION_INFO_V1(dblink_fdw_validator);
1938 Datum
1939 dblink_fdw_validator(PG_FUNCTION_ARGS)
1940 {
1941 List *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
1942 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 if (!options)
1955 {
1956 options = PQconndefaults();
1957 if (!options) /* assume reason for failure is OOM */
1958 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 foreach(cell, options_list)
1966 {
1967 DefElem *def = (DefElem *) lfirst(cell);
1968
1969 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 bool has_valid_options = false;
1980
1981 initClosestMatch(&match_state, def->defname, 4);
1982 for (opt = options; opt->keyword; opt++)
1983 {
1984 if (is_valid_dblink_option(options, opt->keyword, context))
1985 {
1986 has_valid_options = true;
1987 updateClosestMatch(&match_state, opt->keyword);
1988 }
1989 }
1990
1991 closest_match = getClosestMatch(&match_state);
1992 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 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 get_pkey_attnames(Relation rel, int16 *indnkeyatts)
2019 {
2020 Relation indexRelation;
2021 ScanKeyData skey;
2022 SysScanDesc scan;
2023 HeapTuple indexTuple;
2024 int i;
2025 char **result = NULL;
2026 TupleDesc tupdesc;
2027
2028 /* initialize indnkeyatts to 0 in case no primary key exists */
2029 *indnkeyatts = 0;
2030
2031 tupdesc = rel->rd_att;
2032
2033 /* Prepare to scan pg_index for entries having indrelid = this rel. */
2034 indexRelation = table_open(IndexRelationId, AccessShareLock);
2035 ScanKeyInit(&skey,
2036 Anum_pg_index_indrelid,
2037 BTEqualStrategyNumber, F_OIDEQ,
2038 ObjectIdGetDatum(RelationGetRelid(rel)));
2039
2040 scan = systable_beginscan(indexRelation, IndexIndrelidIndexId, true,
2041 NULL, 1, &skey);
2042
2043 while (HeapTupleIsValid(indexTuple = systable_getnext(scan)))
2044 {
2045 Form_pg_index index = (Form_pg_index) GETSTRUCT(indexTuple);
2046
2047 /* we're only interested if it is the primary key */
2048 if (index->indisprimary)
2049 {
2050 *indnkeyatts = index->indnkeyatts;
2051 if (*indnkeyatts > 0)
2052 {
2053 result = palloc_array(char *, *indnkeyatts);
2054
2055 for (i = 0; i < *indnkeyatts; i++)
2056 result[i] = SPI_fname(tupdesc, index->indkey.values[i]);
2057 }
2058 break;
2059 }
2060 }
2061
2062 systable_endscan(scan);
2063 table_close(indexRelation, AccessShareLock);
2064
2065 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 get_text_array_contents(ArrayType *array, int *numitems)
2074 {
2075 int ndim = ARR_NDIM(array);
2076 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 *numitems = nitems = ArrayGetNItems(ndim, dims);
2090
2091 get_typlenbyvalalign(ARR_ELEMTYPE(array),
2092 &typlen, &typbyval, &typalign);
2093
2094 values = palloc_array(char *, nitems);
2095
2096 ptr = ARR_DATA_PTR(array);
2097 bitmap = ARR_NULLBITMAP(array);
2098 bitmask = 1;
2099
2100 for (i = 0; i < nitems; i++)
2101 {
2102 if (bitmap && (*bitmap & bitmask) == 0)
2103 {
2104 values[i] = NULL;
2105 }
2106 else
2107 {
2108 values[i] = TextDatumGetCString(PointerGetDatum(ptr));
2109 ptr = att_addlength_pointer(ptr, typlen, ptr);
2110 ptr = (char *) att_align_nominal(ptr, typalign);
2111 }
2112
2113 /* advance bitmap pointer if any */
2114 if (bitmap)
2115 {
2116 bitmask <<= 1;
2117 if (bitmask == 0x100)
2118 {
2119 bitmap++;
2120 bitmask = 1;
2121 }
2122 }
2123 }
2124
2125 return values;
2126 }
2127
2128 static char *
2129 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 initStringInfo(&buf);
2142
2143 /* get relation name including any needed schema prefix and quoting */
2144 relname = generate_relation_name(rel);
2145
2146 tupdesc = rel->rd_att;
2147 natts = tupdesc->natts;
2148
2149 tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
2150 if (!tuple)
2151 ereport(ERROR,
2152 (errcode(ERRCODE_CARDINALITY_VIOLATION),
2153 errmsg("source row not found")));
2154
2155 appendStringInfo(&buf, "INSERT INTO %s(", relname);
2156
2157 needComma = false;
2158 for (i = 0; i < natts; i++)
2159 {
2160 Form_pg_attribute att = TupleDescAttr(tupdesc, i);
2161
2162 if (att->attisdropped)
2163 continue;
2164
2165 if (needComma)
2166 appendStringInfoChar(&buf, ',');
2167
2168 appendStringInfoString(&buf,
2169 quote_ident_cstr(NameStr(att->attname)));
2170 needComma = true;
2171 }
2172
2173 appendStringInfoString(&buf, ") VALUES(");
2174
2175 /*
2176 * Note: i is physical column number (counting from 0).
2177 */
2178 needComma = false;
2179 for (i = 0; i < natts; i++)
2180 {
2181 if (TupleDescAttr(tupdesc, i)->attisdropped)
2182 continue;
2183
2184 if (needComma)
2185 appendStringInfoChar(&buf, ',');
2186
2187 key = get_attnum_pk_pos(pkattnums, pknumatts, i);
2188
2189 if (key >= 0)
2190 val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
2191 else
2192 val = SPI_getvalue(tuple, tupdesc, i + 1);
2193
2194 if (val != NULL)
2195 {
2196 appendStringInfoString(&buf, quote_literal_cstr(val));
2197 pfree(val);
2198 }
2199 else
2200 appendStringInfoString(&buf, "NULL");
2201 needComma = true;
2202 }
2203 appendStringInfoChar(&buf, ')');
2204
2205 return buf.data;
2206 }
2207
2208 static char *
2209 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 initStringInfo(&buf);
2217
2218 /* get relation name including any needed schema prefix and quoting */
2219 relname = generate_relation_name(rel);
2220
2221 tupdesc = rel->rd_att;
2222
2223 appendStringInfo(&buf, "DELETE FROM %s WHERE ", relname);
2224 for (i = 0; i < pknumatts; i++)
2225 {
2226 int pkattnum = pkattnums[i];
2227 Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2228
2229 if (i > 0)
2230 appendStringInfoString(&buf, " AND ");
2231
2232 appendStringInfoString(&buf,
2233 quote_ident_cstr(NameStr(attr->attname)));
2234
2235 if (tgt_pkattvals[i] != NULL)
2236 appendStringInfo(&buf, " = %s",
2237 quote_literal_cstr(tgt_pkattvals[i]));
2238 else
2239 appendStringInfoString(&buf, " IS NULL");
2240 }
2241
2242 return buf.data;
2243 }
2244
2245 static char *
2246 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 initStringInfo(&buf);
2259
2260 /* get relation name including any needed schema prefix and quoting */
2261 relname = generate_relation_name(rel);
2262
2263 tupdesc = rel->rd_att;
2264 natts = tupdesc->natts;
2265
2266 tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
2267 if (!tuple)
2268 ereport(ERROR,
2269 (errcode(ERRCODE_CARDINALITY_VIOLATION),
2270 errmsg("source row not found")));
2271
2272 appendStringInfo(&buf, "UPDATE %s SET ", relname);
2273
2274 /*
2275 * Note: i is physical column number (counting from 0).
2276 */
2277 needComma = false;
2278 for (i = 0; i < natts; i++)
2279 {
2280 Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
2281
2282 if (attr->attisdropped)
2283 continue;
2284
2285 if (needComma)
2286 appendStringInfoString(&buf, ", ");
2287
2288 appendStringInfo(&buf, "%s = ",
2289 quote_ident_cstr(NameStr(attr->attname)));
2290
2291 key = get_attnum_pk_pos(pkattnums, pknumatts, i);
2292
2293 if (key >= 0)
2294 val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
2295 else
2296 val = SPI_getvalue(tuple, tupdesc, i + 1);
2297
2298 if (val != NULL)
2299 {
2300 appendStringInfoString(&buf, quote_literal_cstr(val));
2301 pfree(val);
2302 }
2303 else
2304 appendStringInfoString(&buf, "NULL");
2305 needComma = true;
2306 }
2307
2308 appendStringInfoString(&buf, " WHERE ");
2309
2310 for (i = 0; i < pknumatts; i++)
2311 {
2312 int pkattnum = pkattnums[i];
2313 Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2314
2315 if (i > 0)
2316 appendStringInfoString(&buf, " AND ");
2317
2318 appendStringInfoString(&buf,
2319 quote_ident_cstr(NameStr(attr->attname)));
2320
2321 val = tgt_pkattvals[i];
2322
2323 if (val != NULL)
2324 appendStringInfo(&buf, " = %s", quote_literal_cstr(val));
2325 else
2326 appendStringInfoString(&buf, " IS NULL");
2327 }
2328
2329 return buf.data;
2330 }
2331
2332 /*
2333 * Return a properly quoted identifier.
2334 * Uses quote_ident in quote.c
2335 */
2336 static char *
2337 quote_ident_cstr(char *rawstr)
2338 {
2339 text *rawstr_text;
2340 text *result_text;
2341 char *result;
2342
2343 rawstr_text = cstring_to_text(rawstr);
2344 result_text = DatumGetTextPP(DirectFunctionCall1(quote_ident,
2345 PointerGetDatum(rawstr_text)));
2346 result = text_to_cstring(result_text);
2347
2348 return result;
2349 }
2350
2351 static int
2352 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 for (i = 0; i < pknumatts; i++)
2360 if (key == pkattnums[i])
2361 return i;
2362
2363 return -1;
2364 }
2365
2366 static HeapTuple
2367 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 if ((ret = SPI_connect()) < 0)
2381 /* internal error */
2382 elog(ERROR, "SPI connect failure - returned %d", ret);
2383
2384 initStringInfo(&buf);
2385
2386 /* get relation name including any needed schema prefix and quoting */
2387 relname = generate_relation_name(rel);
2388
2389 tupdesc = rel->rd_att;
2390 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 appendStringInfoString(&buf, "SELECT ");
2400
2401 for (i = 0; i < natts; i++)
2402 {
2403 Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
2404
2405 if (i > 0)
2406 appendStringInfoString(&buf, ", ");
2407
2408 if (attr->attisdropped)
2409 appendStringInfoString(&buf, "NULL");
2410 else
2411 appendStringInfoString(&buf,
2412 quote_ident_cstr(NameStr(attr->attname)));
2413 }
2414
2415 appendStringInfo(&buf, " FROM %s WHERE ", relname);
2416
2417 for (i = 0; i < pknumatts; i++)
2418 {
2419 int pkattnum = pkattnums[i];
2420 Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2421
2422 if (i > 0)
2423 appendStringInfoString(&buf, " AND ");
2424
2425 appendStringInfoString(&buf,
2426 quote_ident_cstr(NameStr(attr->attname)));
2427
2428 if (src_pkattvals[i] != NULL)
2429 appendStringInfo(&buf, " = %s",
2430 quote_literal_cstr(src_pkattvals[i]));
2431 else
2432 appendStringInfoString(&buf, " IS NULL");
2433 }
2434
2435 /*
2436 * Retrieve the desired tuple
2437 */
2438 ret = SPI_exec(buf.data, 0);
2439 pfree(buf.data);
2440
2441 /*
2442 * Only allow one qualifying tuple
2443 */
2444 if ((ret == SPI_OK_SELECT) && (SPI_processed > 1))
2445 ereport(ERROR,
2446 (errcode(ERRCODE_CARDINALITY_VIOLATION),
2447 errmsg("source criteria matched more than one record")));
2448
2449 else if (ret == SPI_OK_SELECT && SPI_processed == 1)
2450 {
2451 SPITupleTable *tuptable = SPI_tuptable;
2452
2453 tuple = SPI_copytuple(tuptable->vals[0]);
2454 SPI_finish();
2455
2456 return tuple;
2457 }
2458 else
2459 {
2460 /*
2461 * no qualifying tuples
2462 */
2463 SPI_finish();
2464
2465 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 get_rel_from_relname(text *relname_text, LOCKMODE lockmode, AclMode aclmode)
2481 {
2482 RangeVar *relvar;
2483 Relation rel;
2484 AclResult aclresult;
2485
2486 relvar = makeRangeVarFromNameList(textToQualifiedNameList(relname_text));
2487 rel = table_openrv(relvar, lockmode);
2488
2489 aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
2490 aclmode);
2491 if (aclresult != ACLCHECK_OK)
2492 aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
2493 RelationGetRelationName(rel));
2494
2495 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 generate_relation_name(Relation rel)
2506 {
2507 char *nspname;
2508 char *result;
2509
2510 /* Qualify the name if not visible in search path */
2511 if (RelationIsVisible(RelationGetRelid(rel)))
2512 nspname = NULL;
2513 else
2514 nspname = get_namespace_name(rel->rd_rel->relnamespace);
2515
2516 result = quote_qualified_identifier(nspname, RelationGetRelationName(rel));
2517
2518 return result;
2519 }
2520
2521
2522 static remoteConn *
2523 getConnectionByName(const char *name)
2524 {
2525 remoteConnHashEnt *hentry;
2526 char *key;
2527
2528 if (!remoteConnHash)
2529 remoteConnHash = createConnHash();
2530
2531 key = pstrdup(name);
2532 truncate_identifier(key, strlen(key), false);
2533 hentry = (remoteConnHashEnt *) hash_search(remoteConnHash,
2534 key, HASH_FIND, NULL);
2535
2536 if (hentry)
2537 return hentry->rconn;
2538
2539 return NULL;
2540 }
2541
2542 static HTAB *
2543 createConnHash(void)
2544 {
2545 HASHCTL ctl;
2546
2547 ctl.keysize = NAMEDATALEN;
2548 ctl.entrysize = sizeof(remoteConnHashEnt);
2549
2550 return hash_create("Remote Con hash", NUMCONN, &ctl,
2551 HASH_ELEM | HASH_STRINGS);
2552 }
2553
2554 static void
2555 createNewConnection(const char *name, remoteConn *rconn)
2556 {
2557 remoteConnHashEnt *hentry;
2558 bool found;
2559 char *key;
2560
2561 if (!remoteConnHash)
2562 remoteConnHash = createConnHash();
2563
2564 key = pstrdup(name);
2565 truncate_identifier(key, strlen(key), true);
2566 hentry = (remoteConnHashEnt *) hash_search(remoteConnHash, key,
2567 HASH_ENTER, &found);
2568
2569 if (found)
2570 {
2571 libpqsrv_disconnect(rconn->conn);
2572 pfree(rconn);
2573
2574 ereport(ERROR,
2575 (errcode(ERRCODE_DUPLICATE_OBJECT),
2576 errmsg("duplicate connection name")));
2577 }
2578
2579 hentry->rconn = rconn;
2580 }
2581
2582 static void
2583 deleteConnection(const char *name)
2584 {
2585 remoteConnHashEnt *hentry;
2586 bool found;
2587 char *key;
2588
2589 if (!remoteConnHash)
2590 remoteConnHash = createConnHash();
2591
2592 key = pstrdup(name);
2593 truncate_identifier(key, strlen(key), false);
2594 hentry = (remoteConnHashEnt *) hash_search(remoteConnHash,
2595 key, HASH_REMOVE, &found);
2596
2597 if (!hentry)
2598 ereport(ERROR,
2599 (errcode(ERRCODE_UNDEFINED_OBJECT),
2600 errmsg("undefined connection name")));
2601 }
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 dblink_security_check(PGconn *conn, remoteConn *rconn, const char *connstr)
2610 {
2611 /* Superuser bypasses security check */
2612 if (superuser())
2613 return;
2614
2615 /* If password was used to connect, make sure it was one provided */
2616 if (PQconnectionUsedPassword(conn) && dblink_connstr_has_pw(connstr))
2617 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 libpqsrv_disconnect(conn);
2627 if (rconn)
2628 pfree(rconn);
2629
2630 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 dblink_connstr_has_pw(const char *connstr)
2645 {
2646 PQconninfoOption *options;
2647 PQconninfoOption *option;
2648 bool connstr_gives_password = false;
2649
2650 options = PQconninfoParse(connstr, NULL);
2651 if (options)
2652 {
2653 for (option = options; option->keyword != NULL; option++)
2654 {
2655 if (strcmp(option->keyword, "password") == 0)
2656 {
2657 if (option->val != NULL && option->val[0] != '\0')
2658 {
2659 connstr_gives_password = true;
2660 break;
2661 }
2662 }
2663 }
2664 PQconninfoFree(options);
2665 }
2666
2667 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 dblink_connstr_check(const char *connstr)
2680 {
2681 if (superuser())
2682 return;
2683
2684 if (dblink_connstr_has_pw(connstr))
2685 return;
2686
2687 #ifdef ENABLE_GSS
2688 if (be_gssapi_get_delegation(MyProcPort))
2689 return;
2690 #endif
2691
2692 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 dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
2708 bool fail, const char *fmt,...)
2709 {
2710 int level;
2711 char *pg_diag_sqlstate = PQresultErrorField(res, PG_DIAG_SQLSTATE);
2712 char *pg_diag_message_primary = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
2713 char *pg_diag_message_detail = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
2714 char *pg_diag_message_hint = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
2715 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 if (fail)
2725 level = ERROR;
2726 else
2727 level = NOTICE;
2728
2729 if (pg_diag_sqlstate)
2730 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 sqlstate = ERRCODE_CONNECTION_FAILURE;
2737
2738 message_primary = xpstrdup(pg_diag_message_primary);
2739 message_detail = xpstrdup(pg_diag_message_detail);
2740 message_hint = xpstrdup(pg_diag_message_hint);
2741 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 if (message_primary == NULL)
2749 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 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 va_start(ap, fmt);
2767 vsnprintf(dblink_context_msg, sizeof(dblink_context_msg), fmt, ap);
2768 va_end(ap);
2769
2770 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 }
2784
2785 /*
2786 * Obtain connection string for a foreign server
2787 */
2788 static char *
2789 get_connect_string(const char *servername)
2790 {
2791 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 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 if (!options)
2811 {
2812 options = PQconndefaults();
2813 if (!options) /* assume reason for failure is OOM */
2814 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 srvname = pstrdup(servername);
2822 truncate_identifier(srvname, strlen(srvname), false);
2823 foreign_server = GetForeignServerByName(srvname, true);
2824
2825 if (foreign_server)
2826 {
2827 Oid serverid = foreign_server->serverid;
2828 Oid fdwid = foreign_server->fdwid;
2829 Oid userid = GetUserId();
2830
2831 user_mapping = GetUserMapping(userid, serverid);
2832 fdw = GetForeignDataWrapper(fdwid);
2833
2834 /* Check permissions, user must have usage on the server. */
2835 aclresult = object_aclcheck(ForeignServerRelationId, serverid, userid, ACL_USAGE);
2836 if (aclresult != ACLCHECK_OK)
2837 aclcheck_error(aclresult, OBJECT_FOREIGN_SERVER, foreign_server->servername);
2838
2839 foreach(cell, fdw->options)
2840 {
2841 DefElem *def = lfirst(cell);
2842
2843 if (is_valid_dblink_option(options, def->defname, ForeignDataWrapperRelationId))
2844 appendStringInfo(&buf, "%s='%s' ", def->defname,
2845 escape_param_str(strVal(def->arg)));
2846 }
2847
2848 foreach(cell, foreign_server->options)
2849 {
2850 DefElem *def = lfirst(cell);
2851
2852 if (is_valid_dblink_option(options, def->defname, ForeignServerRelationId))
2853 appendStringInfo(&buf, "%s='%s' ", def->defname,
2854 escape_param_str(strVal(def->arg)));
2855 }
2856
2857 foreach(cell, user_mapping->options)
2858 {
2859
2860 DefElem *def = lfirst(cell);
2861
2862 if (is_valid_dblink_option(options, def->defname, UserMappingRelationId))
2863 appendStringInfo(&buf, "%s='%s' ", def->defname,
2864 escape_param_str(strVal(def->arg)));
2865 }
2866
2867 return buf.data;
2868 }
2869 else
2870 return NULL;
2871 }
2872
2873 /*
2874 * Escaping libpq connect parameter strings.
2875 *
2876 * Replaces "'" with "\'" and "\" with "\\".
2877 */
2878 static char *
2879 escape_param_str(const char *str)
2880 {
2881 const char *cp;
2882 StringInfoData buf;
2883
2884 initStringInfo(&buf);
2885
2886 for (cp = str; *cp; cp++)
2887 {
2888 if (*cp == '\\' || *cp == '\'')
2889 appendStringInfoChar(&buf, '\\');
2890 appendStringInfoChar(&buf, *cp);
2891 }
2892
2893 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 validate_pkattnums(Relation rel,
2913 int2vector *pkattnums_arg, int32 pknumatts_arg,
2914 int **pkattnums, int *pknumatts)
2915 {
2916 TupleDesc tupdesc = rel->rd_att;
2917 int natts = tupdesc->natts;
2918 int i;
2919
2920 /* Don't take more array elements than there are */
2921 pknumatts_arg = Min(pknumatts_arg, pkattnums_arg->dim1);
2922
2923 /* Must have at least one pk attnum selected */
2924 if (pknumatts_arg <= 0)
2925 ereport(ERROR,
2926 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2927 errmsg("number of key attributes must be > 0")));
2928
2929 /* Allocate output array */
2930 *pkattnums = palloc_array(int, pknumatts_arg);
2931 *pknumatts = pknumatts_arg;
2932
2933 /* Validate attnums and convert to internal form */
2934 for (i = 0; i < pknumatts_arg; i++)
2935 {
2936 int pkattnum = pkattnums_arg->values[i];
2937 int lnum;
2938 int j;
2939
2940 /* Can throw error immediately if out of range */
2941 if (pkattnum <= 0 || pkattnum > natts)
2942 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 lnum = 0;
2948 for (j = 0; j < natts; j++)
2949 {
2950 /* dropped columns don't count */
2951 if (TupleDescAttr(tupdesc, j)->attisdropped)
2952 continue;
2953
2954 if (++lnum == pkattnum)
2955 break;
2956 }
2957
2958 if (j < natts)
2959 (*pkattnums)[i] = j;
2960 else
2961 ereport(ERROR,
2962 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2963 errmsg("invalid attribute number %d", pkattnum)));
2964 }
2965 }
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 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 for (opt = options; opt->keyword; opt++)
2990 {
2991 if (strcmp(opt->keyword, option) == 0)
2992 break;
2993 }
2994 if (opt->keyword == NULL)
2995 return false;
2996
2997 /* Disallow debug options (particularly "replication") */
2998 if (strchr(opt->dispchar, 'D'))
2999 return false;
3000
3001 /* Disallow "client_encoding" */
3002 if (strcmp(opt->keyword, "client_encoding") == 0)
3003 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 if (strcmp(opt->keyword, "user") == 0 || strchr(opt->dispchar, '*'))
3010 {
3011 if (context != UserMappingRelationId)
3012 return false;
3013 }
3014 else
3015 {
3016 if (context != ForeignServerRelationId)
3017 return false;
3018 }
3019
3020 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 applyRemoteGucs(PGconn *conn)
3035 {
3036 static const char *const GUCsAffectingIO[] = {
3037 "DateStyle",
3038 "IntervalStyle"
3039 };
3040
3041 int nestlevel = -1;
3042 int i;
3043
3044 for (i = 0; i < lengthof(GUCsAffectingIO); i++)
3045 {
3046 const char *gucName = GUCsAffectingIO[i];
3047 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 if (remoteVal == NULL)
3057 continue;
3058
3059 /*
3060 * Avoid GUC-setting overhead if the remote and local GUCs already
3061 * have the same value.
3062 */
3063 localVal = GetConfigOption(gucName, false, false);
3064 Assert(localVal != NULL);
3065
3066 if (strcmp(remoteVal, localVal) == 0)
3067 continue;
3068
3069 /* Create new GUC nest level if we didn't already */
3070 if (nestlevel < 0)
3071 nestlevel = NewGUCNestLevel();
3072
3073 /* Apply the option (this will throw error on failure) */
3074 (void) set_config_option(gucName, remoteVal,
3075 PGC_USERSET, PGC_S_SESSION,
3076 GUC_ACTION_SAVE, true, 0, false);
3077 }
3078
3079 return nestlevel;
3080 }
3081
3082 /*
3083 * Restore local GUCs after they have been overlaid with remote settings.
3084 */
3085 static void
3086 restoreLocalGucs(int nestlevel)
3087 {
3088 /* Do nothing if no new nestlevel was created */
3089 if (nestlevel > 0)
3090 AtEOXact_GUC(true, nestlevel);
3091 }
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