aboutsummaryrefslogtreecommitdiff
path: root/src/bin/pg_dump/pg_dumpall.c
blob: c3a769237407b50181763c2d71cc9afa77bad784 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
/*-------------------------------------------------------------------------
 *
 * pg_dumpall
 *
 * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dumpall.c,v 1.11 2002/11/29 16:38:42 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres_fe.h"

#include <unistd.h>
#ifdef ENABLE_NLS
#include <locale.h>
#endif
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#ifndef HAVE_STRDUP
#include "strdup.h"
#endif
#include <errno.h>

#include "dumputils.h"
#include "libpq-fe.h"
#include "pg_backup.h"
#include "pqexpbuffer.h"

#define _(x) gettext((x))


static char *progname;

static void help(void);

static void dumpUsers(PGconn *conn);
static void dumpGroups(PGconn *conn);
static void dumpCreateDB(PGconn *conn);
static void dumpDatabaseConfig(PGconn *conn, const char *dbname);
static void dumpUserConfig(PGconn *conn, const char *username);
static void makeAlterConfigCommand(const char *arrayitem, const char *type, const char *name);
static void dumpDatabases(PGconn *conn);

static int	runPgDump(const char *dbname);
static PGconn *connectDatabase(const char *dbname, const char *pghost, const char *pgport,
				const char *pguser, bool require_password);
static PGresult *executeQuery(PGconn *conn, const char *query);
static char *findPgDump(const char *argv0);


char	   *pgdumploc;
PQExpBuffer pgdumpopts;
bool		output_clean = false;
bool		verbose = false;
int			server_version;



int
main(int argc, char *argv[])
{
	char	   *pghost = NULL;
	char	   *pgport = NULL;
	char	   *pguser = NULL;
	bool		force_password = false;
	bool		globals_only = false;
	PGconn	   *conn;
	int			c;

#ifdef HAVE_GETOPT_LONG
	static struct option long_options[] = {
		{"clean", no_argument, NULL, 'c'},
		{"inserts", no_argument, NULL, 'd'},
		{"attribute-inserts", no_argument, NULL, 'D'},
		{"column-inserts", no_argument, NULL, 'D'},
		{"host", required_argument, NULL, 'h'},
		{"ignore-version", no_argument, NULL, 'i'},
		{"oids", no_argument, NULL, 'o'},
		{"port", required_argument, NULL, 'p'},
		{"password", no_argument, NULL, 'W'},
		{"username", required_argument, NULL, 'U'},
		{"verbose", no_argument, NULL, 'v'},
		{NULL, 0, NULL, 0}
	};

	int			optindex;
#endif

#ifdef ENABLE_NLS
	setlocale(LC_ALL, "");
	bindtextdomain("pg_dump", LOCALEDIR);
	textdomain("pg_dump");
#endif

	if (!strrchr(argv[0], '/'))
		progname = argv[0];
	else
		progname = strrchr(argv[0], '/') + 1;

	if (argc > 1)
	{
		if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
		{
			help();
			exit(0);
		}
		if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
		{
			puts("pg_dumpall (PostgreSQL) " PG_VERSION);
			exit(0);
		}
	}

	pgdumploc = findPgDump(argv[0]);
	pgdumpopts = createPQExpBuffer();

#ifdef HAVE_GETOPT_LONG
	while ((c = getopt_long(argc, argv, "cdDgh:iop:U:vW", long_options, &optindex)) != -1)
#else
	while ((c = getopt(argc, argv, "cdDgh:iop:U:vW")) != -1)
#endif
	{
		switch (c)
		{
			case 'c':
				output_clean = true;
				break;

			case 'd':
			case 'D':
				appendPQExpBuffer(pgdumpopts, " -%c", c);
				break;

			case 'g':
				globals_only = true;
				break;

			case 'h':
				pghost = optarg;
				appendPQExpBuffer(pgdumpopts, " -h '%s'", pghost);
				break;

			case 'i':
			case 'o':
				appendPQExpBuffer(pgdumpopts, " -%c", c);
				break;

			case 'p':
				pgport = optarg;
				appendPQExpBuffer(pgdumpopts, " -p '%s'", pgport);
				break;

			case 'U':
				pguser = optarg;
				appendPQExpBuffer(pgdumpopts, " -U '%s'", pguser);
				break;

			case 'v':
				verbose = true;
				appendPQExpBuffer(pgdumpopts, " -v");
				break;

			case 'W':
				force_password = true;
				appendPQExpBuffer(pgdumpopts, " -W");
				break;

			default:
				fprintf(stderr, _("Try '%s --help' for more information.\n"), progname);
				exit(1);
		}
	}

	if (optind < argc)
	{
		fprintf(stderr,
				_("%s: too many command line options (first is '%s')\n"
				  "Try '%s --help' for more information.\n"),
				progname, argv[optind], progname);
		exit(1);
	}


	conn = connectDatabase("template1", pghost, pgport, pguser, force_password);

	printf("--\n");
	printf("-- PostgreSQL database cluster dump\n");
	printf("--\n\n");
	printf("\\connect \"template1\"\n\n");

	dumpUsers(conn);
	dumpGroups(conn);

	if (globals_only)
		goto end;

	dumpCreateDB(conn);
	dumpDatabases(conn);

end:
	PQfinish(conn);
	exit(0);
}



static void
help(void)
{
	printf(_("%s extracts a PostgreSQL database cluster into an SQL script file.\n\n"), progname);
	printf(_("Usage:\n"));
	printf(_("  %s [OPTION]...\n"), progname);

	printf(_("\nOptions:\n"));
#ifdef HAVE_GETOPT_LONG
	printf(_("  -c, --clean              clean (drop) databases prior to create\n"));
	printf(_("  -d, --inserts            dump data as INSERT, rather than COPY, commands\n"));
	printf(_("  -D, --column-inserts     dump data as INSERT commands with column names\n"));
	printf(_("  -g, --globals-only       dump only global objects, no databases\n"));
	printf(_("  -i, --ignore-version     proceed even when server version mismatches\n"
			 "                           pg_dumpall version\n"));
	printf(_("  -o, --oids               include OIDs in dump\n"));
	printf(_("  -v, --verbose            verbose mode\n"));
#else /* not HAVE_GETOPT_LONG */
	printf(_("  -c                       clean (drop) databases prior to create\n"));
	printf(_("  -d                       dump data as INSERT, rather than COPY, commands\n"));
	printf(_("  -D                       dump data as INSERT commands with column names\n"));
	printf(_("  -g                       dump only global objects, no databases\n"));
	printf(_("  -i                       proceed even when server version mismatches\n"
			 "                           pg_dumpall version\n"));
	printf(_("  -o                       include OIDs in dump\n"));
	printf(_("  -v                       verbose mode\n"));
#endif /* not HAVE_GETOPT_LONG */
	printf(_("  --help                   show this help, then exit\n"));
	printf(_("  --version                output version information, then exit\n"));

	printf(_("\nConnection options:\n"));
#ifdef HAVE_GETOPT_LONG
	printf(_("  -h, --host=HOSTNAME      database server host name\n"));
	printf(_("  -p, --port=PORT          database server port number\n"));
	printf(_("  -U, --username=NAME      connect as specified database user\n"));
	printf(_("  -W, --password           force password prompt (should happen automatically)\n"));
#else /* not HAVE_GETOPT_LONG */
	printf(_("  -h HOSTNAME              database server host name\n"));
	printf(_("  -p PORT                  database server port number\n"));
	printf(_("  -U NAME                  connect as specified database user\n"));
	printf(_("  -W                       force password prompt (should happen automatically)\n"));
#endif /* not HAVE_GETOPT_LONG */

	printf(_("\nThe SQL script will be written to the standard output.\n\n"));
	printf(_("Report bugs to <pgsql-bugs@postgresql.org>.\n"));
}



/*
 * Dump users (but not the user created by initdb).
 */
static void
dumpUsers(PGconn *conn)
{
	PGresult   *res;
	int			i;

	printf("--\n-- Users\n--\n\n");
	printf("DELETE FROM pg_shadow WHERE usesysid <> (SELECT datdba FROM pg_database WHERE datname = 'template0');\n\n");

	res = executeQuery(conn,
					   "SELECT usename, usesysid, passwd, usecreatedb, usesuper, CAST(valuntil AS timestamp) "
					   "FROM pg_shadow "
					   "WHERE usesysid <> (SELECT datdba FROM pg_database WHERE datname = 'template0');");

	for (i = 0; i < PQntuples(res); i++)
	{
		PQExpBuffer buf = createPQExpBuffer();
		const char *username;

		username = PQgetvalue(res, i, 0);
		appendPQExpBuffer(buf, "CREATE USER %s WITH SYSID %s",
						  fmtId(username),
						  PQgetvalue(res, i, 1));

		if (!PQgetisnull(res, i, 2))
		{
			appendPQExpBuffer(buf, " PASSWORD ");
			appendStringLiteral(buf, PQgetvalue(res, i, 2), true);
		}

		if (strcmp(PQgetvalue(res, i, 3), "t") == 0)
			appendPQExpBuffer(buf, " CREATEDB");
		else
			appendPQExpBuffer(buf, " NOCREATEDB");

		if (strcmp(PQgetvalue(res, i, 4), "t") == 0)
			appendPQExpBuffer(buf, " CREATEUSER");
		else
			appendPQExpBuffer(buf, " NOCREATEUSER");

		if (!PQgetisnull(res, i, 5))
			appendPQExpBuffer(buf, " VALID UNTIL '%s'", PQgetvalue(res, i, 5));

		appendPQExpBuffer(buf, ";\n");

		printf("%s", buf->data);
		destroyPQExpBuffer(buf);

		if (server_version >= 70300)
			dumpUserConfig(conn, username);
	}

	PQclear(res);
	printf("\n\n");
}



/*
 * Dump groups.
 */
static void
dumpGroups(PGconn *conn)
{
	PGresult   *res;
	int			i;

	printf("--\n-- Groups\n--\n\n");
	printf("DELETE FROM pg_group;\n\n");

	res = executeQuery(conn, "SELECT groname, grosysid, grolist FROM pg_group;");

	for (i = 0; i < PQntuples(res); i++)
	{
		PQExpBuffer buf = createPQExpBuffer();
		char	   *val;
		char	   *tok;

		appendPQExpBuffer(buf, "CREATE GROUP %s WITH SYSID %s;\n",
						  fmtId(PQgetvalue(res, i, 0)),
						  PQgetvalue(res, i, 1));

		val = strdup(PQgetvalue(res, i, 2));
		tok = strtok(val, ",{}");
		do
		{
			PGresult   *res2;
			PQExpBuffer buf2 = createPQExpBuffer();
			int			j;

			appendPQExpBuffer(buf2, "SELECT usename FROM pg_shadow WHERE usesysid = %s;", tok);
			res2 = executeQuery(conn, buf2->data);
			destroyPQExpBuffer(buf2);

			for (j = 0; j < PQntuples(res2); j++)
			{
				appendPQExpBuffer(buf, "ALTER GROUP %s ", fmtId(PQgetvalue(res, i, 0)));
				appendPQExpBuffer(buf, "ADD USER %s;\n", fmtId(PQgetvalue(res2, j, 0)));
			}

			PQclear(res2);

			tok = strtok(NULL, "{},");
		}
		while (tok);

		printf("%s", buf->data);
		destroyPQExpBuffer(buf);
	}

	PQclear(res);
	printf("\n\n");
}



/*
 * Dump commands to create each database.
 *
 * To minimize the number of reconnections (and possibly ensuing
 * password prompts) required by the output script, we emit all CREATE
 * DATABASE commands during the initial phase of the script, and then
 * run pg_dump for each database to dump the contents of that
 * database.  We skip databases marked not datallowconn, since we'd be
 * unable to connect to them anyway (and besides, we don't want to
 * dump template0).
 */
static void
dumpCreateDB(PGconn *conn)
{
	PGresult   *res;
	int			i;

	printf("--\n-- Database creation\n--\n\n");

	/*
	 * Basically this query returns: dbname, dbowner, encoding,
	 * istemplate, dbpath
	 */
	res = executeQuery(conn, "SELECT datname, coalesce(usename, (select usename from pg_shadow where usesysid=(select datdba from pg_database where datname='template0'))), pg_encoding_to_char(d.encoding), datistemplate, datpath FROM pg_database d LEFT JOIN pg_shadow u ON (datdba = usesysid) WHERE datallowconn ORDER BY 1;");

	for (i = 0; i < PQntuples(res); i++)
	{
		PQExpBuffer buf;
		char	   *dbname = PQgetvalue(res, i, 0);
		char	   *dbowner = PQgetvalue(res, i, 1);
		char	   *dbencoding = PQgetvalue(res, i, 2);
		char	   *dbistemplate = PQgetvalue(res, i, 3);
		char	   *dbpath = PQgetvalue(res, i, 4);

		if (strcmp(dbname, "template1") == 0)
			continue;

		buf = createPQExpBuffer();

		if (output_clean)
			appendPQExpBuffer(buf, "DROP DATABASE %s\n;", fmtId(dbname));

		appendPQExpBuffer(buf, "CREATE DATABASE %s", fmtId(dbname));
		appendPQExpBuffer(buf, " WITH OWNER = %s TEMPLATE = template0", fmtId(dbowner));

		if (strcmp(dbpath, "") != 0)
		{
			appendPQExpBuffer(buf, " LOCATION = ");
			appendStringLiteral(buf, dbpath, true);
		}

		appendPQExpBuffer(buf, " ENCODING = ");
		appendStringLiteral(buf, dbencoding, true);

		appendPQExpBuffer(buf, ";\n");

		if (strcmp(dbistemplate, "t") == 0)
		{
			appendPQExpBuffer(buf, "UPDATE pg_database SET datistemplate = 't' WHERE datname = ");
			appendStringLiteral(buf, dbname, true);
			appendPQExpBuffer(buf, ";\n");
		}
		printf("%s", buf->data);
		destroyPQExpBuffer(buf);

		if (server_version >= 70300)
			dumpDatabaseConfig(conn, dbname);
	}

	PQclear(res);
	printf("\n\n");
}



/*
 * Dump database-specific configuration
 */
static void
dumpDatabaseConfig(PGconn *conn, const char *dbname)
{
	PQExpBuffer buf = createPQExpBuffer();
	int			count = 1;

	for (;;)
	{
		PGresult   *res;

		printfPQExpBuffer(buf, "SELECT datconfig[%d] FROM pg_database WHERE datname = ", count);
		appendStringLiteral(buf, dbname, true);
		appendPQExpBuffer(buf, ";");

		res = executeQuery(conn, buf->data);
		if (!PQgetisnull(res, 0, 0))
		{
			makeAlterConfigCommand(PQgetvalue(res, 0, 0), "DATABASE", dbname);
			PQclear(res);
			count++;
		}
		else
		{
			PQclear(res);
			break;
		}
	}

	destroyPQExpBuffer(buf);
}



/*
 * Dump user-specific configuration
 */
static void
dumpUserConfig(PGconn *conn, const char *username)
{
	PQExpBuffer buf = createPQExpBuffer();
	int			count = 1;

	for (;;)
	{
		PGresult   *res;

		printfPQExpBuffer(buf, "SELECT useconfig[%d] FROM pg_shadow WHERE usename = ", count);
		appendStringLiteral(buf, username, true);
		appendPQExpBuffer(buf, ";");

		res = executeQuery(conn, buf->data);
		if (!PQgetisnull(res, 0, 0))
		{
			makeAlterConfigCommand(PQgetvalue(res, 0, 0), "USER", username);
			PQclear(res);
			count++;
		}
		else
		{
			PQclear(res);
			break;
		}
	}

	destroyPQExpBuffer(buf);
}



/*
 * Helper function for dumpXXXConfig().
 */
static void
makeAlterConfigCommand(const char *arrayitem, const char *type, const char *name)
{
	char	   *pos;
	char	   *mine;
	PQExpBuffer buf = createPQExpBuffer();

	mine = strdup(arrayitem);
	pos = strchr(mine, '=');
	if (pos == NULL)
		return;

	*pos = 0;
	appendPQExpBuffer(buf, "ALTER %s %s ", type, fmtId(name));
	appendPQExpBuffer(buf, "SET %s TO ", fmtId(mine));
	appendStringLiteral(buf, pos + 1, false);
	appendPQExpBuffer(buf, ";\n");

	printf("%s", buf->data);
	destroyPQExpBuffer(buf);
	free(mine);
}



/*
 * Dump contents of databases.
 */
static void
dumpDatabases(PGconn *conn)
{
	PGresult   *res;
	int			i;

	res = executeQuery(conn, "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;");
	for (i = 0; i < PQntuples(res); i++)
	{
		int			ret;

		char	   *dbname = PQgetvalue(res, i, 0);

		if (verbose)
			fprintf(stderr, _("%s: dumping database \"%s\"...\n"), progname, dbname);

		printf("\\connect %s\n", fmtId(dbname));
		ret = runPgDump(dbname);
		if (ret != 0)
		{
			fprintf(stderr, _("%s: pg_dump failed on %s, exiting\n"), progname, dbname);
			exit(1);
		}
	}

	PQclear(res);
}



/*
 * Run pg_dump on dbname.
 */
static int
runPgDump(const char *dbname)
{
	PQExpBuffer cmd = createPQExpBuffer();
	const char *p;
	int			ret;

	appendPQExpBuffer(cmd, "%s %s -X use-set-session-authorization -Fp '",
					  pgdumploc, pgdumpopts->data);

	/* Shell quoting is not quite like SQL quoting, so can't use fmtId */
	for (p = dbname; *p; p++)
	{
		if (*p == '\'')
			appendPQExpBuffer(cmd, "'\"'\"'");
		else
			appendPQExpBufferChar(cmd, *p);
	}

	appendPQExpBufferChar(cmd, '\'');

	if (verbose)
		fprintf(stderr, _("%s: running %s\n"), progname, cmd->data);

	fflush(stdout);
	fflush(stderr);

	ret = system(cmd->data);

	destroyPQExpBuffer(cmd);

	return ret;
}



/*
 * Make a database connection with the given parameters.  An
 * interactive password prompt is automatically issued if required.
 */
static PGconn *
connectDatabase(const char *dbname, const char *pghost, const char *pgport,
				const char *pguser, bool require_password)
{
	PGconn	   *conn;
	char	   *password = NULL;
	bool		need_pass = false;
	PGresult   *res;

	if (require_password)
		password = simple_prompt("Password: ", 100, false);

	/*
	 * Start the connection.  Loop until we have a password if requested
	 * by backend.
	 */
	do
	{
		need_pass = false;
		conn = PQsetdbLogin(pghost, pgport, NULL, NULL, dbname, pguser, password);

		if (!conn)
		{
			fprintf(stderr, _("%s: could not connect to database %s\n"),
					progname, dbname);
			exit(1);
		}

		if (PQstatus(conn) == CONNECTION_BAD &&
			strcmp(PQerrorMessage(conn), "fe_sendauth: no password supplied\n") == 0 &&
			!feof(stdin))
		{
			PQfinish(conn);
			need_pass = true;
			free(password);
			password = NULL;
			password = simple_prompt("Password: ", 100, false);
		}
	} while (need_pass);

	if (password)
		free(password);

	/* check to see that the backend connection was successfully made */
	if (PQstatus(conn) == CONNECTION_BAD)
	{
		fprintf(stderr, _("%s: could not connect to database %s: %s\n"),
				progname, dbname, PQerrorMessage(conn));
		exit(1);
	}

	res = executeQuery(conn, "SELECT version();");
	if (PQntuples(res) != 1)
	{
		fprintf(stderr, _("%s: could not get server version\n"), progname);
		exit(1);
	}
	else
	{
		char *val = PQgetvalue(res, 0, 0);
		server_version = parse_version(val + strcspn(val, "0123456789"));
		if (server_version < 0)
		{
			fprintf(stderr, _("%s: could not parse server version \"%s\"\n"), progname, val);
			exit(1);
		}
	}
	PQclear(res);

	return conn;
}



/*
 * Run a query, return the results, exit program on failure.
 */
static PGresult *
executeQuery(PGconn *conn, const char *query)
{
	PGresult   *res;

	res = PQexec(conn, query);
	if (!res ||
		PQresultStatus(res) != PGRES_TUPLES_OK)
	{
		fprintf(stderr, _("%s: query failed: %s"), progname, PQerrorMessage(conn));
		fprintf(stderr, _("%s: query was: %s\n"), progname, query);
		PQfinish(conn);
		exit(1);
	}

	return res;
}



/*
 * Find location of pg_dump executable.
 */
static char *
findPgDump(const char *argv0)
{
	char	   *last;
	PQExpBuffer cmd;
	static char *result = NULL;

	if (result)
		return result;

	cmd = createPQExpBuffer();
	last = strrchr(argv0, '/');

	if (!last)
		appendPQExpBuffer(cmd, "pg_dump");
	else
	{
		char	   *dir = strdup(argv0);

		*(dir + (last - argv0)) = '\0';
		appendPQExpBuffer(cmd, "%s/pg_dump", dir);
	}

	result = strdup(cmd->data);

	appendPQExpBuffer(cmd, " -V >/dev/null 2>&1");
	if (system(cmd->data) == 0)
		goto end;

	result = BINDIR "/pg_dump";
	if (system(BINDIR "/pg_dump -V >/dev/null 2>&1") == 0)
		goto end;

	fprintf(stderr, _("%s: could not find pg_dump\n"
		"Make sure it is in the path or in the same directory as %s.\n"),
			progname, progname);
	exit(1);

end:
	destroyPQExpBuffer(cmd);
	return result;
}