1 /*-------------------------------------------------------------------------
2 *
3 * xlogfuncs.c
4 *
5 * PostgreSQL write-ahead log manager user interface functions
6 *
7 * This file contains WAL control and information functions.
8 *
9 *
10 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
11 * Portions Copyright (c) 1994, Regents of the University of California
12 *
13 * src/backend/access/transam/xlogfuncs.c
14 *
15 *-------------------------------------------------------------------------
16 */
17 #include "postgres.h"
18
19 #include "access/htup_details.h"
20 #include "access/xlog.h"
21 #include "access/xlog_internal.h"
22 #include "access/xlogutils.h"
23 #include "catalog/catalog.h"
24 #include "catalog/pg_type.h"
25 #include "funcapi.h"
26 #include "miscadmin.h"
27 #include "replication/walreceiver.h"
28 #include "storage/smgr.h"
29 #include "utils/builtins.h"
30 #include "utils/memutils.h"
31 #include "utils/numeric.h"
32 #include "utils/guc.h"
33 #include "utils/pg_lsn.h"
34 #include "utils/timestamp.h"
35 #include "utils/tuplestore.h"
36 #include "storage/fd.h"
37 #include "storage/ipc.h"
38
39
40 /*
41 * Store label file and tablespace map during non-exclusive backups.
42 */
43 static StringInfo label_file;
44 static StringInfo tblspc_map_file;
45
46 /*
47 * Called when the backend exits with a running non-exclusive base backup,
48 * to clean up state.
49 */
50 static void
nonexclusive_base_backup_cleanup(int code,Datum arg)51 nonexclusive_base_backup_cleanup(int code, Datum arg)
52 {
53 do_pg_abort_backup();
54 ereport(WARNING,
55 (errmsg("aborting backup due to backend exiting before pg_stop_backup was called")));
56 }
57
58 /*
59 * pg_start_backup: set up for taking an on-line backup dump
60 *
61 * Essentially what this does is to create a backup label file in $PGDATA,
62 * where it will be archived as part of the backup dump. The label file
63 * contains the user-supplied label string (typically this would be used
64 * to tell where the backup dump will be stored) and the starting time and
65 * starting WAL location for the dump.
66 *
67 * Permission checking for this function is managed through the normal
68 * GRANT system.
69 */
70 Datum
pg_start_backup(PG_FUNCTION_ARGS)71 pg_start_backup(PG_FUNCTION_ARGS)
72 {
73 text *backupid = PG_GETARG_TEXT_PP(0);
74 bool fast = PG_GETARG_BOOL(1);
75 bool exclusive = PG_GETARG_BOOL(2);
76 char *backupidstr;
77 XLogRecPtr startpoint;
78 DIR *dir;
79 SessionBackupState status = get_backup_status();
80
81 backupidstr = text_to_cstring(backupid);
82
83 if (status == SESSION_BACKUP_NON_EXCLUSIVE)
84 ereport(ERROR,
85 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
86 errmsg("a backup is already in progress in this session")));
87
88 /* Make sure we can open the directory with tablespaces in it */
89 dir = AllocateDir("pg_tblspc");
90 if (!dir)
91 ereport(ERROR,
92 (errmsg("could not open directory \"%s\": %m", "pg_tblspc")));
93
94 if (exclusive)
95 {
96 startpoint = do_pg_start_backup(backupidstr, fast, NULL, NULL,
97 dir, NULL, NULL, false, true);
98 }
99 else
100 {
101 MemoryContext oldcontext;
102
103 /*
104 * Label file and tablespace map file need to be long-lived, since
105 * they are read in pg_stop_backup.
106 */
107 oldcontext = MemoryContextSwitchTo(TopMemoryContext);
108 label_file = makeStringInfo();
109 tblspc_map_file = makeStringInfo();
110 MemoryContextSwitchTo(oldcontext);
111
112 startpoint = do_pg_start_backup(backupidstr, fast, NULL, label_file,
113 dir, NULL, tblspc_map_file, false, true);
114
115 before_shmem_exit(nonexclusive_base_backup_cleanup, (Datum) 0);
116 }
117
118 FreeDir(dir);
119
120 PG_RETURN_LSN(startpoint);
121 }
122
123 /*
124 * pg_stop_backup: finish taking an on-line backup dump
125 *
126 * We write an end-of-backup WAL record, and remove the backup label file
127 * created by pg_start_backup, creating a backup history file in pg_wal
128 * instead (whence it will immediately be archived). The backup history file
129 * contains the same info found in the label file, plus the backup-end time
130 * and WAL location. Before 9.0, the backup-end time was read from the backup
131 * history file at the beginning of archive recovery, but we now use the WAL
132 * record for that and the file is for informational and debug purposes only.
133 *
134 * Note: different from CancelBackup which just cancels online backup mode.
135 *
136 * Note: this version is only called to stop an exclusive backup. The function
137 * pg_stop_backup_v2 (overloaded as pg_stop_backup in SQL) is called to
138 * stop non-exclusive backups.
139 *
140 * Permission checking for this function is managed through the normal
141 * GRANT system.
142 */
143 Datum
pg_stop_backup(PG_FUNCTION_ARGS)144 pg_stop_backup(PG_FUNCTION_ARGS)
145 {
146 XLogRecPtr stoppoint;
147 SessionBackupState status = get_backup_status();
148
149 if (status == SESSION_BACKUP_NON_EXCLUSIVE)
150 ereport(ERROR,
151 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
152 errmsg("non-exclusive backup in progress"),
153 errhint("Did you mean to use pg_stop_backup('f')?")));
154
155 /*
156 * Exclusive backups were typically started in a different connection, so
157 * don't try to verify that status of backup is set to
158 * SESSION_BACKUP_EXCLUSIVE in this function. Actual verification that an
159 * exclusive backup is in fact running is handled inside
160 * do_pg_stop_backup.
161 */
162 stoppoint = do_pg_stop_backup(NULL, true, NULL);
163
164 PG_RETURN_LSN(stoppoint);
165 }
166
167
168 /*
169 * pg_stop_backup_v2: finish taking exclusive or nonexclusive on-line backup.
170 *
171 * Works the same as pg_stop_backup, except for non-exclusive backups it returns
172 * the backup label and tablespace map files as text fields in as part of the
173 * resultset.
174 *
175 * The first parameter (variable 'exclusive') allows the user to tell us if
176 * this is an exclusive or a non-exclusive backup.
177 *
178 * The second parameter (variable 'waitforarchive'), which is optional,
179 * allows the user to choose if they want to wait for the WAL to be archived
180 * or if we should just return as soon as the WAL record is written.
181 *
182 * Permission checking for this function is managed through the normal
183 * GRANT system.
184 */
185 Datum
pg_stop_backup_v2(PG_FUNCTION_ARGS)186 pg_stop_backup_v2(PG_FUNCTION_ARGS)
187 {
188 ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
189 TupleDesc tupdesc;
190 Tuplestorestate *tupstore;
191 MemoryContext per_query_ctx;
192 MemoryContext oldcontext;
193 Datum values[3];
194 bool nulls[3];
195
196 bool exclusive = PG_GETARG_BOOL(0);
197 bool waitforarchive = PG_GETARG_BOOL(1);
198 XLogRecPtr stoppoint;
199 SessionBackupState status = get_backup_status();
200
201 /* check to see if caller supports us returning a tuplestore */
202 if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
203 ereport(ERROR,
204 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
205 errmsg("set-valued function called in context that cannot accept a set")));
206 if (!(rsinfo->allowedModes & SFRM_Materialize))
207 ereport(ERROR,
208 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
209 errmsg("materialize mode required, but it is not " \
210 "allowed in this context")));
211
212 /* Build a tuple descriptor for our result type */
213 if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
214 elog(ERROR, "return type must be a row type");
215
216 per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
217 oldcontext = MemoryContextSwitchTo(per_query_ctx);
218
219 tupstore = tuplestore_begin_heap(true, false, work_mem);
220 rsinfo->returnMode = SFRM_Materialize;
221 rsinfo->setResult = tupstore;
222 rsinfo->setDesc = tupdesc;
223
224 MemoryContextSwitchTo(oldcontext);
225
226 MemSet(values, 0, sizeof(values));
227 MemSet(nulls, 0, sizeof(nulls));
228
229 if (exclusive)
230 {
231 if (status == SESSION_BACKUP_NON_EXCLUSIVE)
232 ereport(ERROR,
233 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
234 errmsg("non-exclusive backup in progress"),
235 errhint("Did you mean to use pg_stop_backup('f')?")));
236
237 /*
238 * Stop the exclusive backup, and since we're in an exclusive backup
239 * return NULL for both backup_label and tablespace_map.
240 */
241 stoppoint = do_pg_stop_backup(NULL, waitforarchive, NULL);
242
243 nulls[1] = true;
244 nulls[2] = true;
245 }
246 else
247 {
248 if (status != SESSION_BACKUP_NON_EXCLUSIVE)
249 ereport(ERROR,
250 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
251 errmsg("non-exclusive backup is not in progress"),
252 errhint("Did you mean to use pg_stop_backup('t')?")));
253
254 /*
255 * Stop the non-exclusive backup. Return a copy of the backup label
256 * and tablespace map so they can be written to disk by the caller.
257 */
258 stoppoint = do_pg_stop_backup(label_file->data, waitforarchive, NULL);
259 cancel_before_shmem_exit(nonexclusive_base_backup_cleanup, (Datum) 0);
260
261 values[1] = CStringGetTextDatum(label_file->data);
262 values[2] = CStringGetTextDatum(tblspc_map_file->data);
263
264 /* Free structures allocated in TopMemoryContext */
265 pfree(label_file->data);
266 pfree(label_file);
267 label_file = NULL;
268 pfree(tblspc_map_file->data);
269 pfree(tblspc_map_file);
270 tblspc_map_file = NULL;
271 }
272
273 /* Stoppoint is included on both exclusive and nonexclusive backups */
274 values[0] = LSNGetDatum(stoppoint);
275
276 tuplestore_putvalues(tupstore, tupdesc, values, nulls);
277 tuplestore_donestoring(typstore);
278
279 return (Datum) 0;
280 }
281
282 /*
283 * pg_switch_wal: switch to next xlog file
284 *
285 * Permission checking for this function is managed through the normal
286 * GRANT system.
287 */
288 Datum
pg_switch_wal(PG_FUNCTION_ARGS)289 pg_switch_wal(PG_FUNCTION_ARGS)
290 {
291 XLogRecPtr switchpoint;
292
293 if (RecoveryInProgress())
294 ereport(ERROR,
295 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
296 errmsg("recovery is in progress"),
297 errhint("WAL control functions cannot be executed during recovery.")));
298
299 switchpoint = RequestXLogSwitch(false);
300
301 /*
302 * As a convenience, return the WAL location of the switch record
303 */
304 PG_RETURN_LSN(switchpoint);
305 }
306
307 /*
308 * pg_create_restore_point: a named point for restore
309 *
310 * Permission checking for this function is managed through the normal
311 * GRANT system.
312 */
313 Datum
pg_create_restore_point(PG_FUNCTION_ARGS)314 pg_create_restore_point(PG_FUNCTION_ARGS)
315 {
316 text *restore_name = PG_GETARG_TEXT_PP(0);
317 char *restore_name_str;
318 XLogRecPtr restorepoint;
319
320 if (RecoveryInProgress())
321 ereport(ERROR,
322 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
323 (errmsg("recovery is in progress"),
324 errhint("WAL control functions cannot be executed during recovery."))));
325
326 if (!XLogIsNeeded())
327 ereport(ERROR,
328 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
329 errmsg("WAL level not sufficient for creating a restore point"),
330 errhint("wal_level must be set to \"replica\" or \"logical\" at server start.")));
331
332 restore_name_str = text_to_cstring(restore_name);
333
334 if (strlen(restore_name_str) >= MAXFNAMELEN)
335 ereport(ERROR,
336 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
337 errmsg("value too long for restore point (maximum %d characters)", MAXFNAMELEN - 1)));
338
339 restorepoint = XLogRestorePoint(restore_name_str);
340
341 /*
342 * As a convenience, return the WAL location of the restore point record
343 */
344 PG_RETURN_LSN(restorepoint);
345 }
346
347 /*
348 * Report the current WAL write location (same format as pg_start_backup etc)
349 *
350 * This is useful for determining how much of WAL is visible to an external
351 * archiving process. Note that the data before this point is written out
352 * to the kernel, but is not necessarily synced to disk.
353 */
354 Datum
pg_current_wal_lsn(PG_FUNCTION_ARGS)355 pg_current_wal_lsn(PG_FUNCTION_ARGS)
356 {
357 XLogRecPtr current_recptr;
358
359 if (RecoveryInProgress())
360 ereport(ERROR,
361 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
362 errmsg("recovery is in progress"),
363 errhint("WAL control functions cannot be executed during recovery.")));
364
365 current_recptr = GetXLogWriteRecPtr();
366
367 PG_RETURN_LSN(current_recptr);
368 }
369
370 /*
371 * Report the current WAL insert location (same format as pg_start_backup etc)
372 *
373 * This function is mostly for debugging purposes.
374 */
375 Datum
pg_current_wal_insert_lsn(PG_FUNCTION_ARGS)376 pg_current_wal_insert_lsn(PG_FUNCTION_ARGS)
377 {
378 XLogRecPtr current_recptr;
379
380 if (RecoveryInProgress())
381 ereport(ERROR,
382 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
383 errmsg("recovery is in progress"),
384 errhint("WAL control functions cannot be executed during recovery.")));
385
386 current_recptr = GetXLogInsertRecPtr();
387
388 PG_RETURN_LSN(current_recptr);
389 }
390
391 /*
392 * Report the current WAL flush location (same format as pg_start_backup etc)
393 *
394 * This function is mostly for debugging purposes.
395 */
396 Datum
pg_current_wal_flush_lsn(PG_FUNCTION_ARGS)397 pg_current_wal_flush_lsn(PG_FUNCTION_ARGS)
398 {
399 XLogRecPtr current_recptr;
400
401 if (RecoveryInProgress())
402 ereport(ERROR,
403 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
404 errmsg("recovery is in progress"),
405 errhint("WAL control functions cannot be executed during recovery.")));
406
407 current_recptr = GetFlushRecPtr();
408
409 PG_RETURN_LSN(current_recptr);
410 }
411
412 /*
413 * Report the last WAL receive location (same format as pg_start_backup etc)
414 *
415 * This is useful for determining how much of WAL is guaranteed to be received
416 * and synced to disk by walreceiver.
417 */
418 Datum
pg_last_wal_receive_lsn(PG_FUNCTION_ARGS)419 pg_last_wal_receive_lsn(PG_FUNCTION_ARGS)
420 {
421 XLogRecPtr recptr;
422
423 recptr = GetWalRcvWriteRecPtr(NULL, NULL);
424
425 if (recptr == 0)
426 PG_RETURN_NULL();
427
428 PG_RETURN_LSN(recptr);
429 }
430
431 /*
432 * Report the last WAL replay location (same format as pg_start_backup etc)
433 *
434 * This is useful for determining how much of WAL is visible to read-only
435 * connections during recovery.
436 */
437 Datum
pg_last_wal_replay_lsn(PG_FUNCTION_ARGS)438 pg_last_wal_replay_lsn(PG_FUNCTION_ARGS)
439 {
440 XLogRecPtr recptr;
441
442 recptr = GetXLogReplayRecPtr(NULL);
443
444 if (recptr == 0)
445 PG_RETURN_NULL();
446
447 PG_RETURN_LSN(recptr);
448 }
449
450 /*
451 * Compute an xlog file name and decimal byte offset given a WAL location,
452 * such as is returned by pg_stop_backup() or pg_switch_wal().
453 *
454 * Note that a location exactly at a segment boundary is taken to be in
455 * the previous segment. This is usually the right thing, since the
456 * expected usage is to determine which xlog file(s) are ready to archive.
457 */
458 Datum
pg_walfile_name_offset(PG_FUNCTION_ARGS)459 pg_walfile_name_offset(PG_FUNCTION_ARGS)
460 {
461 XLogSegNo xlogsegno;
462 uint32 xrecoff;
463 XLogRecPtr locationpoint = PG_GETARG_LSN(0);
464 char xlogfilename[MAXFNAMELEN];
465 Datum values[2];
466 bool isnull[2];
467 TupleDesc resultTupleDesc;
468 HeapTuple resultHeapTuple;
469 Datum result;
470
471 if (RecoveryInProgress())
472 ereport(ERROR,
473 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
474 errmsg("recovery is in progress"),
475 errhint("pg_walfile_name_offset() cannot be executed during recovery.")));
476
477 /*
478 * Construct a tuple descriptor for the result row. This must match this
479 * function's pg_proc entry!
480 */
481 resultTupleDesc = CreateTemplateTupleDesc(2, false);
482 TupleDescInitEntry(resultTupleDesc, (AttrNumber) 1, "file_name",
483 TEXTOID, -1, 0);
484 TupleDescInitEntry(resultTupleDesc, (AttrNumber) 2, "file_offset",
485 INT4OID, -1, 0);
486
487 resultTupleDesc = BlessTupleDesc(resultTupleDesc);
488
489 /*
490 * xlogfilename
491 */
492 XLByteToPrevSeg(locationpoint, xlogsegno);
493 XLogFileName(xlogfilename, ThisTimeLineID, xlogsegno);
494
495 values[0] = CStringGetTextDatum(xlogfilename);
496 isnull[0] = false;
497
498 /*
499 * offset
500 */
501 xrecoff = locationpoint % XLogSegSize;
502
503 values[1] = UInt32GetDatum(xrecoff);
504 isnull[1] = false;
505
506 /*
507 * Tuple jam: Having first prepared your Datums, then squash together
508 */
509 resultHeapTuple = heap_form_tuple(resultTupleDesc, values, isnull);
510
511 result = HeapTupleGetDatum(resultHeapTuple);
512
513 PG_RETURN_DATUM(result);
514 }
515
516 /*
517 * Compute an xlog file name given a WAL location,
518 * such as is returned by pg_stop_backup() or pg_switch_wal().
519 */
520 Datum
pg_walfile_name(PG_FUNCTION_ARGS)521 pg_walfile_name(PG_FUNCTION_ARGS)
522 {
523 XLogSegNo xlogsegno;
524 XLogRecPtr locationpoint = PG_GETARG_LSN(0);
525 char xlogfilename[MAXFNAMELEN];
526
527 if (RecoveryInProgress())
528 ereport(ERROR,
529 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
530 errmsg("recovery is in progress"),
531 errhint("pg_walfile_name() cannot be executed during recovery.")));
532
533 XLByteToPrevSeg(locationpoint, xlogsegno);
534 XLogFileName(xlogfilename, ThisTimeLineID, xlogsegno);
535
536 PG_RETURN_TEXT_P(cstring_to_text(xlogfilename));
537 }
538
539 /*
540 * pg_wal_replay_pause - pause recovery now
541 *
542 * Permission checking for this function is managed through the normal
543 * GRANT system.
544 */
545 Datum
pg_wal_replay_pause(PG_FUNCTION_ARGS)546 pg_wal_replay_pause(PG_FUNCTION_ARGS)
547 {
548 if (!RecoveryInProgress())
549 ereport(ERROR,
550 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
551 errmsg("recovery is not in progress"),
552 errhint("Recovery control functions can only be executed during recovery.")));
553
554 SetRecoveryPause(true);
555
556 PG_RETURN_VOID();
557 }
558
559 /*
560 * pg_wal_replay_resume - resume recovery now
561 *
562 * Permission checking for this function is managed through the normal
563 * GRANT system.
564 */
565 Datum
pg_wal_replay_resume(PG_FUNCTION_ARGS)566 pg_wal_replay_resume(PG_FUNCTION_ARGS)
567 {
568 if (!RecoveryInProgress())
569 ereport(ERROR,
570 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
571 errmsg("recovery is not in progress"),
572 errhint("Recovery control functions can only be executed during recovery.")));
573
574 SetRecoveryPause(false);
575
576 PG_RETURN_VOID();
577 }
578
579 /*
580 * pg_is_wal_replay_paused
581 */
582 Datum
pg_is_wal_replay_paused(PG_FUNCTION_ARGS)583 pg_is_wal_replay_paused(PG_FUNCTION_ARGS)
584 {
585 if (!RecoveryInProgress())
586 ereport(ERROR,
587 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
588 errmsg("recovery is not in progress"),
589 errhint("Recovery control functions can only be executed during recovery.")));
590
591 PG_RETURN_BOOL(RecoveryIsPaused());
592 }
593
594 /*
595 * Returns timestamp of latest processed commit/abort record.
596 *
597 * When the server has been started normally without recovery the function
598 * returns NULL.
599 */
600 Datum
pg_last_xact_replay_timestamp(PG_FUNCTION_ARGS)601 pg_last_xact_replay_timestamp(PG_FUNCTION_ARGS)
602 {
603 TimestampTz xtime;
604
605 xtime = GetLatestXTime();
606 if (xtime == 0)
607 PG_RETURN_NULL();
608
609 PG_RETURN_TIMESTAMPTZ(xtime);
610 }
611
612 /*
613 * Returns bool with current recovery mode, a global state.
614 */
615 Datum
pg_is_in_recovery(PG_FUNCTION_ARGS)616 pg_is_in_recovery(PG_FUNCTION_ARGS)
617 {
618 PG_RETURN_BOOL(RecoveryInProgress());
619 }
620
621 /*
622 * Compute the difference in bytes between two WAL locations.
623 */
624 Datum
pg_wal_lsn_diff(PG_FUNCTION_ARGS)625 pg_wal_lsn_diff(PG_FUNCTION_ARGS)
626 {
627 Datum result;
628
629 result = DirectFunctionCall2(pg_lsn_mi,
630 PG_GETARG_DATUM(0),
631 PG_GETARG_DATUM(1));
632
633 PG_RETURN_NUMERIC(result);
634 }
635
636 /*
637 * Returns bool with current on-line backup mode, a global state.
638 */
639 Datum
pg_is_in_backup(PG_FUNCTION_ARGS)640 pg_is_in_backup(PG_FUNCTION_ARGS)
641 {
642 PG_RETURN_BOOL(BackupInProgress());
643 }
644
645 /*
646 * Returns start time of an online exclusive backup.
647 *
648 * When there's no exclusive backup in progress, the function
649 * returns NULL.
650 */
651 Datum
pg_backup_start_time(PG_FUNCTION_ARGS)652 pg_backup_start_time(PG_FUNCTION_ARGS)
653 {
654 Datum xtime;
655 FILE *lfp;
656 char fline[MAXPGPATH];
657 char backup_start_time[30];
658
659 /*
660 * See if label file is present
661 */
662 lfp = AllocateFile(BACKUP_LABEL_FILE, "r");
663 if (lfp == NULL)
664 {
665 if (errno != ENOENT)
666 ereport(ERROR,
667 (errcode_for_file_access(),
668 errmsg("could not read file \"%s\": %m",
669 BACKUP_LABEL_FILE)));
670 PG_RETURN_NULL();
671 }
672
673 /*
674 * Parse the file to find the START TIME line.
675 */
676 backup_start_time[0] = '\0';
677 while (fgets(fline, sizeof(fline), lfp) != NULL)
678 {
679 if (sscanf(fline, "START TIME: %25[^\n]\n", backup_start_time) == 1)
680 break;
681 }
682
683 /* Check for a read error. */
684 if (ferror(lfp))
685 ereport(ERROR,
686 (errcode_for_file_access(),
687 errmsg("could not read file \"%s\": %m", BACKUP_LABEL_FILE)));
688
689 /* Close the backup label file. */
690 if (FreeFile(lfp))
691 ereport(ERROR,
692 (errcode_for_file_access(),
693 errmsg("could not close file \"%s\": %m", BACKUP_LABEL_FILE)));
694
695 if (strlen(backup_start_time) == 0)
696 ereport(ERROR,
697 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
698 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE)));
699
700 /*
701 * Convert the time string read from file to TimestampTz form.
702 */
703 xtime = DirectFunctionCall3(timestamptz_in,
704 CStringGetDatum(backup_start_time),
705 ObjectIdGetDatum(InvalidOid),
706 Int32GetDatum(-1));
707
708 PG_RETURN_DATUM(xtime);
709 }
710