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xlogreader.c
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1 /*-------------------------------------------------------------------------
2  *
3  * xlogreader.c
4  * Generic XLog reading facility
5  *
6  * Portions Copyright (c) 2013-2019, PostgreSQL Global Development Group
7  *
8  * IDENTIFICATION
9  * src/backend/access/transam/xlogreader.c
10  *
11  * NOTES
12  * See xlogreader.h for more notes on this facility.
13  *
14  * This file is compiled as both front-end and backend code, so it
15  * may not use ereport, server-defined static variables, etc.
16  *-------------------------------------------------------------------------
17  */
18 #include "postgres.h"
19 
20 #include "access/transam.h"
21 #include "access/xlogrecord.h"
22 #include "access/xlog_internal.h"
23 #include "access/xlogreader.h"
24 #include "catalog/pg_control.h"
25 #include "common/pg_lzcompress.h"
26 #include "replication/origin.h"
27 
28 #ifndef FRONTEND
29 #include "miscadmin.h"
30 #include "utils/memutils.h"
31 #endif
32 
33 
34 static void report_invalid_record(XLogReaderState *state, const char *fmt,...)
35  pg_attribute_printf(2, 3);
36 static bool allocate_recordbuf(XLogReaderState *state, uint32 reclength);
37 static int ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr,
38  int reqLen);
39 static void XLogReaderInvalReadState(XLogReaderState *state);
40 static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr,
41  XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess);
42 static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record,
43  XLogRecPtr recptr);
44 static void ResetDecoder(XLogReaderState *state);
45 
46 /* size of the buffer allocated for error message. */
47 #define MAX_ERRORMSG_LEN 1000
48 
49 /*
50  * Construct a string in state->errormsg_buf explaining what's wrong with
51  * the current record being read.
52  */
53 static void
54 report_invalid_record(XLogReaderState *state, const char *fmt,...)
55 {
56  va_list args;
57 
58  fmt = _(fmt);
59 
60  va_start(args, fmt);
61  vsnprintf(state->errormsg_buf, MAX_ERRORMSG_LEN, fmt, args);
62  va_end(args);
63 }
64 
65 /*
66  * Allocate and initialize a new XLogReader.
67  *
68  * Returns NULL if the xlogreader couldn't be allocated.
69  */
71 XLogReaderAllocate(int wal_segment_size, const char *waldir,
72  XLogPageReadCB pagereadfunc, void *private_data)
73 {
74  XLogReaderState *state;
75 
76  state = (XLogReaderState *)
79  if (!state)
80  return NULL;
81 
82  state->max_block_id = -1;
83 
84  /*
85  * Permanently allocate readBuf. We do it this way, rather than just
86  * making a static array, for two reasons: (1) no need to waste the
87  * storage in most instantiations of the backend; (2) a static char array
88  * isn't guaranteed to have any particular alignment, whereas
89  * palloc_extended() will provide MAXALIGN'd storage.
90  */
91  state->readBuf = (char *) palloc_extended(XLOG_BLCKSZ,
93  if (!state->readBuf)
94  {
95  pfree(state);
96  return NULL;
97  }
98 
99  /* Initialize segment info. */
100  WALOpenSegmentInit(&state->seg, &state->segcxt, wal_segment_size,
101  waldir);
102 
103  state->read_page = pagereadfunc;
104  /* system_identifier initialized to zeroes above */
105  state->private_data = private_data;
106  /* ReadRecPtr, EndRecPtr and readLen initialized to zeroes above */
109  if (!state->errormsg_buf)
110  {
111  pfree(state->readBuf);
112  pfree(state);
113  return NULL;
114  }
115  state->errormsg_buf[0] = '\0';
116 
117  /*
118  * Allocate an initial readRecordBuf of minimal size, which can later be
119  * enlarged if necessary.
120  */
121  if (!allocate_recordbuf(state, 0))
122  {
123  pfree(state->errormsg_buf);
124  pfree(state->readBuf);
125  pfree(state);
126  return NULL;
127  }
128 
129  return state;
130 }
131 
132 void
134 {
135  int block_id;
136 
137  for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++)
138  {
139  if (state->blocks[block_id].data)
140  pfree(state->blocks[block_id].data);
141  }
142  if (state->main_data)
143  pfree(state->main_data);
144 
145  pfree(state->errormsg_buf);
146  if (state->readRecordBuf)
147  pfree(state->readRecordBuf);
148  pfree(state->readBuf);
149  pfree(state);
150 }
151 
152 /*
153  * Allocate readRecordBuf to fit a record of at least the given length.
154  * Returns true if successful, false if out of memory.
155  *
156  * readRecordBufSize is set to the new buffer size.
157  *
158  * To avoid useless small increases, round its size to a multiple of
159  * XLOG_BLCKSZ, and make sure it's at least 5*Max(BLCKSZ, XLOG_BLCKSZ) to start
160  * with. (That is enough for all "normal" records, but very large commit or
161  * abort records might need more space.)
162  */
163 static bool
165 {
166  uint32 newSize = reclength;
167 
168  newSize += XLOG_BLCKSZ - (newSize % XLOG_BLCKSZ);
169  newSize = Max(newSize, 5 * Max(BLCKSZ, XLOG_BLCKSZ));
170 
171 #ifndef FRONTEND
172 
173  /*
174  * Note that in much unlucky circumstances, the random data read from a
175  * recycled segment can cause this routine to be called with a size
176  * causing a hard failure at allocation. For a standby, this would cause
177  * the instance to stop suddenly with a hard failure, preventing it to
178  * retry fetching WAL from one of its sources which could allow it to move
179  * on with replay without a manual restart. If the data comes from a past
180  * recycled segment and is still valid, then the allocation may succeed
181  * but record checks are going to fail so this would be short-lived. If
182  * the allocation fails because of a memory shortage, then this is not a
183  * hard failure either per the guarantee given by MCXT_ALLOC_NO_OOM.
184  */
185  if (!AllocSizeIsValid(newSize))
186  return false;
187 
188 #endif
189 
190  if (state->readRecordBuf)
191  pfree(state->readRecordBuf);
192  state->readRecordBuf =
193  (char *) palloc_extended(newSize, MCXT_ALLOC_NO_OOM);
194  if (state->readRecordBuf == NULL)
195  {
196  state->readRecordBufSize = 0;
197  return false;
198  }
199  state->readRecordBufSize = newSize;
200  return true;
201 }
202 
203 /*
204  * Initialize the passed segment structs.
205  */
206 void
208  int segsize, const char *waldir)
209 {
210  seg->ws_file = -1;
211  seg->ws_segno = 0;
212  seg->ws_off = 0;
213  seg->ws_tli = 0;
214 
215  segcxt->ws_segsize = segsize;
216  if (waldir)
217  snprintf(segcxt->ws_dir, MAXPGPATH, "%s", waldir);
218 }
219 
220 /*
221  * Attempt to read an XLOG record.
222  *
223  * If RecPtr is valid, try to read a record at that position. Otherwise
224  * try to read a record just after the last one previously read.
225  *
226  * If the read_page callback fails to read the requested data, NULL is
227  * returned. The callback is expected to have reported the error; errormsg
228  * is set to NULL.
229  *
230  * If the reading fails for some other reason, NULL is also returned, and
231  * *errormsg is set to a string with details of the failure.
232  *
233  * The returned pointer (or *errormsg) points to an internal buffer that's
234  * valid until the next call to XLogReadRecord.
235  */
236 XLogRecord *
237 XLogReadRecord(XLogReaderState *state, XLogRecPtr RecPtr, char **errormsg)
238 {
239  XLogRecord *record;
240  XLogRecPtr targetPagePtr;
241  bool randAccess;
242  uint32 len,
243  total_len;
244  uint32 targetRecOff;
245  uint32 pageHeaderSize;
246  bool gotheader;
247  int readOff;
248 
249  /*
250  * randAccess indicates whether to verify the previous-record pointer of
251  * the record we're reading. We only do this if we're reading
252  * sequentially, which is what we initially assume.
253  */
254  randAccess = false;
255 
256  /* reset error state */
257  *errormsg = NULL;
258  state->errormsg_buf[0] = '\0';
259 
260  ResetDecoder(state);
261 
262  if (RecPtr == InvalidXLogRecPtr)
263  {
264  /* No explicit start point; read the record after the one we just read */
265  RecPtr = state->EndRecPtr;
266 
267  if (state->ReadRecPtr == InvalidXLogRecPtr)
268  randAccess = true;
269 
270  /*
271  * RecPtr is pointing to end+1 of the previous WAL record. If we're
272  * at a page boundary, no more records can fit on the current page. We
273  * must skip over the page header, but we can't do that until we've
274  * read in the page, since the header size is variable.
275  */
276  }
277  else
278  {
279  /*
280  * Caller supplied a position to start at.
281  *
282  * In this case, the passed-in record pointer should already be
283  * pointing to a valid record starting position.
284  */
285  Assert(XRecOffIsValid(RecPtr));
286  randAccess = true;
287  }
288 
289  state->currRecPtr = RecPtr;
290 
291  targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ);
292  targetRecOff = RecPtr % XLOG_BLCKSZ;
293 
294  /*
295  * Read the page containing the record into state->readBuf. Request enough
296  * byte to cover the whole record header, or at least the part of it that
297  * fits on the same page.
298  */
299  readOff = ReadPageInternal(state,
300  targetPagePtr,
301  Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ));
302  if (readOff < 0)
303  goto err;
304 
305  /*
306  * ReadPageInternal always returns at least the page header, so we can
307  * examine it now.
308  */
309  pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf);
310  if (targetRecOff == 0)
311  {
312  /*
313  * At page start, so skip over page header.
314  */
315  RecPtr += pageHeaderSize;
316  targetRecOff = pageHeaderSize;
317  }
318  else if (targetRecOff < pageHeaderSize)
319  {
320  report_invalid_record(state, "invalid record offset at %X/%X",
321  (uint32) (RecPtr >> 32), (uint32) RecPtr);
322  goto err;
323  }
324 
325  if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) &&
326  targetRecOff == pageHeaderSize)
327  {
328  report_invalid_record(state, "contrecord is requested by %X/%X",
329  (uint32) (RecPtr >> 32), (uint32) RecPtr);
330  goto err;
331  }
332 
333  /* ReadPageInternal has verified the page header */
334  Assert(pageHeaderSize <= readOff);
335 
336  /*
337  * Read the record length.
338  *
339  * NB: Even though we use an XLogRecord pointer here, the whole record
340  * header might not fit on this page. xl_tot_len is the first field of the
341  * struct, so it must be on this page (the records are MAXALIGNed), but we
342  * cannot access any other fields until we've verified that we got the
343  * whole header.
344  */
345  record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ);
346  total_len = record->xl_tot_len;
347 
348  /*
349  * If the whole record header is on this page, validate it immediately.
350  * Otherwise do just a basic sanity check on xl_tot_len, and validate the
351  * rest of the header after reading it from the next page. The xl_tot_len
352  * check is necessary here to ensure that we enter the "Need to reassemble
353  * record" code path below; otherwise we might fail to apply
354  * ValidXLogRecordHeader at all.
355  */
356  if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord)
357  {
358  if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record,
359  randAccess))
360  goto err;
361  gotheader = true;
362  }
363  else
364  {
365  /* XXX: more validation should be done here */
366  if (total_len < SizeOfXLogRecord)
367  {
368  report_invalid_record(state,
369  "invalid record length at %X/%X: wanted %u, got %u",
370  (uint32) (RecPtr >> 32), (uint32) RecPtr,
371  (uint32) SizeOfXLogRecord, total_len);
372  goto err;
373  }
374  gotheader = false;
375  }
376 
377  len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ;
378  if (total_len > len)
379  {
380  /* Need to reassemble record */
381  char *contdata;
382  XLogPageHeader pageHeader;
383  char *buffer;
384  uint32 gotlen;
385 
386  /*
387  * Enlarge readRecordBuf as needed.
388  */
389  if (total_len > state->readRecordBufSize &&
390  !allocate_recordbuf(state, total_len))
391  {
392  /* We treat this as a "bogus data" condition */
393  report_invalid_record(state, "record length %u at %X/%X too long",
394  total_len,
395  (uint32) (RecPtr >> 32), (uint32) RecPtr);
396  goto err;
397  }
398 
399  /* Copy the first fragment of the record from the first page. */
400  memcpy(state->readRecordBuf,
401  state->readBuf + RecPtr % XLOG_BLCKSZ, len);
402  buffer = state->readRecordBuf + len;
403  gotlen = len;
404 
405  do
406  {
407  /* Calculate pointer to beginning of next page */
408  targetPagePtr += XLOG_BLCKSZ;
409 
410  /* Wait for the next page to become available */
411  readOff = ReadPageInternal(state, targetPagePtr,
412  Min(total_len - gotlen + SizeOfXLogShortPHD,
413  XLOG_BLCKSZ));
414 
415  if (readOff < 0)
416  goto err;
417 
418  Assert(SizeOfXLogShortPHD <= readOff);
419 
420  /* Check that the continuation on next page looks valid */
421  pageHeader = (XLogPageHeader) state->readBuf;
422  if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD))
423  {
424  report_invalid_record(state,
425  "there is no contrecord flag at %X/%X",
426  (uint32) (RecPtr >> 32), (uint32) RecPtr);
427  goto err;
428  }
429 
430  /*
431  * Cross-check that xlp_rem_len agrees with how much of the record
432  * we expect there to be left.
433  */
434  if (pageHeader->xlp_rem_len == 0 ||
435  total_len != (pageHeader->xlp_rem_len + gotlen))
436  {
437  report_invalid_record(state,
438  "invalid contrecord length %u at %X/%X",
439  pageHeader->xlp_rem_len,
440  (uint32) (RecPtr >> 32), (uint32) RecPtr);
441  goto err;
442  }
443 
444  /* Append the continuation from this page to the buffer */
445  pageHeaderSize = XLogPageHeaderSize(pageHeader);
446 
447  if (readOff < pageHeaderSize)
448  readOff = ReadPageInternal(state, targetPagePtr,
449  pageHeaderSize);
450 
451  Assert(pageHeaderSize <= readOff);
452 
453  contdata = (char *) state->readBuf + pageHeaderSize;
454  len = XLOG_BLCKSZ - pageHeaderSize;
455  if (pageHeader->xlp_rem_len < len)
456  len = pageHeader->xlp_rem_len;
457 
458  if (readOff < pageHeaderSize + len)
459  readOff = ReadPageInternal(state, targetPagePtr,
460  pageHeaderSize + len);
461 
462  memcpy(buffer, (char *) contdata, len);
463  buffer += len;
464  gotlen += len;
465 
466  /* If we just reassembled the record header, validate it. */
467  if (!gotheader)
468  {
469  record = (XLogRecord *) state->readRecordBuf;
470  if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr,
471  record, randAccess))
472  goto err;
473  gotheader = true;
474  }
475  } while (gotlen < total_len);
476 
477  Assert(gotheader);
478 
479  record = (XLogRecord *) state->readRecordBuf;
480  if (!ValidXLogRecord(state, record, RecPtr))
481  goto err;
482 
483  pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf);
484  state->ReadRecPtr = RecPtr;
485  state->EndRecPtr = targetPagePtr + pageHeaderSize
486  + MAXALIGN(pageHeader->xlp_rem_len);
487  }
488  else
489  {
490  /* Wait for the record data to become available */
491  readOff = ReadPageInternal(state, targetPagePtr,
492  Min(targetRecOff + total_len, XLOG_BLCKSZ));
493  if (readOff < 0)
494  goto err;
495 
496  /* Record does not cross a page boundary */
497  if (!ValidXLogRecord(state, record, RecPtr))
498  goto err;
499 
500  state->EndRecPtr = RecPtr + MAXALIGN(total_len);
501 
502  state->ReadRecPtr = RecPtr;
503  }
504 
505  /*
506  * Special processing if it's an XLOG SWITCH record
507  */
508  if (record->xl_rmid == RM_XLOG_ID &&
509  (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH)
510  {
511  /* Pretend it extends to end of segment */
512  state->EndRecPtr += state->segcxt.ws_segsize - 1;
513  state->EndRecPtr -= XLogSegmentOffset(state->EndRecPtr, state->segcxt.ws_segsize);
514  }
515 
516  if (DecodeXLogRecord(state, record, errormsg))
517  return record;
518  else
519  return NULL;
520 
521 err:
522 
523  /*
524  * Invalidate the read state. We might read from a different source after
525  * failure.
526  */
528 
529  if (state->errormsg_buf[0] != '\0')
530  *errormsg = state->errormsg_buf;
531 
532  return NULL;
533 }
534 
535 /*
536  * Read a single xlog page including at least [pageptr, reqLen] of valid data
537  * via the read_page() callback.
538  *
539  * Returns -1 if the required page cannot be read for some reason; errormsg_buf
540  * is set in that case (unless the error occurs in the read_page callback).
541  *
542  * We fetch the page from a reader-local cache if we know we have the required
543  * data and if there hasn't been any error since caching the data.
544  */
545 static int
546 ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
547 {
548  int readLen;
549  uint32 targetPageOff;
550  XLogSegNo targetSegNo;
551  XLogPageHeader hdr;
552 
553  Assert((pageptr % XLOG_BLCKSZ) == 0);
554 
555  XLByteToSeg(pageptr, targetSegNo, state->segcxt.ws_segsize);
556  targetPageOff = XLogSegmentOffset(pageptr, state->segcxt.ws_segsize);
557 
558  /* check whether we have all the requested data already */
559  if (targetSegNo == state->seg.ws_segno &&
560  targetPageOff == state->seg.ws_off && reqLen <= state->readLen)
561  return state->readLen;
562 
563  /*
564  * Data is not in our buffer.
565  *
566  * Every time we actually read the page, even if we looked at parts of it
567  * before, we need to do verification as the read_page callback might now
568  * be rereading data from a different source.
569  *
570  * Whenever switching to a new WAL segment, we read the first page of the
571  * file and validate its header, even if that's not where the target
572  * record is. This is so that we can check the additional identification
573  * info that is present in the first page's "long" header.
574  */
575  if (targetSegNo != state->seg.ws_segno && targetPageOff != 0)
576  {
577  XLogRecPtr targetSegmentPtr = pageptr - targetPageOff;
578 
579  readLen = state->read_page(state, targetSegmentPtr, XLOG_BLCKSZ,
580  state->currRecPtr,
581  state->readBuf);
582  if (readLen < 0)
583  goto err;
584 
585  /* we can be sure to have enough WAL available, we scrolled back */
586  Assert(readLen == XLOG_BLCKSZ);
587 
588  if (!XLogReaderValidatePageHeader(state, targetSegmentPtr,
589  state->readBuf))
590  goto err;
591  }
592 
593  /*
594  * First, read the requested data length, but at least a short page header
595  * so that we can validate it.
596  */
597  readLen = state->read_page(state, pageptr, Max(reqLen, SizeOfXLogShortPHD),
598  state->currRecPtr,
599  state->readBuf);
600  if (readLen < 0)
601  goto err;
602 
603  Assert(readLen <= XLOG_BLCKSZ);
604 
605  /* Do we have enough data to check the header length? */
606  if (readLen <= SizeOfXLogShortPHD)
607  goto err;
608 
609  Assert(readLen >= reqLen);
610 
611  hdr = (XLogPageHeader) state->readBuf;
612 
613  /* still not enough */
614  if (readLen < XLogPageHeaderSize(hdr))
615  {
616  readLen = state->read_page(state, pageptr, XLogPageHeaderSize(hdr),
617  state->currRecPtr,
618  state->readBuf);
619  if (readLen < 0)
620  goto err;
621  }
622 
623  /*
624  * Now that we know we have the full header, validate it.
625  */
626  if (!XLogReaderValidatePageHeader(state, pageptr, (char *) hdr))
627  goto err;
628 
629  /* update read state information */
630  state->seg.ws_segno = targetSegNo;
631  state->seg.ws_off = targetPageOff;
632  state->readLen = readLen;
633 
634  return readLen;
635 
636 err:
638  return -1;
639 }
640 
641 /*
642  * Invalidate the xlogreader's read state to force a re-read.
643  */
644 static void
646 {
647  state->seg.ws_segno = 0;
648  state->seg.ws_off = 0;
649  state->readLen = 0;
650 }
651 
652 /*
653  * Validate an XLOG record header.
654  *
655  * This is just a convenience subroutine to avoid duplicated code in
656  * XLogReadRecord. It's not intended for use from anywhere else.
657  */
658 static bool
660  XLogRecPtr PrevRecPtr, XLogRecord *record,
661  bool randAccess)
662 {
663  if (record->xl_tot_len < SizeOfXLogRecord)
664  {
665  report_invalid_record(state,
666  "invalid record length at %X/%X: wanted %u, got %u",
667  (uint32) (RecPtr >> 32), (uint32) RecPtr,
668  (uint32) SizeOfXLogRecord, record->xl_tot_len);
669  return false;
670  }
671  if (record->xl_rmid > RM_MAX_ID)
672  {
673  report_invalid_record(state,
674  "invalid resource manager ID %u at %X/%X",
675  record->xl_rmid, (uint32) (RecPtr >> 32),
676  (uint32) RecPtr);
677  return false;
678  }
679  if (randAccess)
680  {
681  /*
682  * We can't exactly verify the prev-link, but surely it should be less
683  * than the record's own address.
684  */
685  if (!(record->xl_prev < RecPtr))
686  {
687  report_invalid_record(state,
688  "record with incorrect prev-link %X/%X at %X/%X",
689  (uint32) (record->xl_prev >> 32),
690  (uint32) record->xl_prev,
691  (uint32) (RecPtr >> 32), (uint32) RecPtr);
692  return false;
693  }
694  }
695  else
696  {
697  /*
698  * Record's prev-link should exactly match our previous location. This
699  * check guards against torn WAL pages where a stale but valid-looking
700  * WAL record starts on a sector boundary.
701  */
702  if (record->xl_prev != PrevRecPtr)
703  {
704  report_invalid_record(state,
705  "record with incorrect prev-link %X/%X at %X/%X",
706  (uint32) (record->xl_prev >> 32),
707  (uint32) record->xl_prev,
708  (uint32) (RecPtr >> 32), (uint32) RecPtr);
709  return false;
710  }
711  }
712 
713  return true;
714 }
715 
716 
717 /*
718  * CRC-check an XLOG record. We do not believe the contents of an XLOG
719  * record (other than to the minimal extent of computing the amount of
720  * data to read in) until we've checked the CRCs.
721  *
722  * We assume all of the record (that is, xl_tot_len bytes) has been read
723  * into memory at *record. Also, ValidXLogRecordHeader() has accepted the
724  * record's header, which means in particular that xl_tot_len is at least
725  * SizeOfXLogRecord.
726  */
727 static bool
729 {
730  pg_crc32c crc;
731 
732  /* Calculate the CRC */
733  INIT_CRC32C(crc);
734  COMP_CRC32C(crc, ((char *) record) + SizeOfXLogRecord, record->xl_tot_len - SizeOfXLogRecord);
735  /* include the record header last */
736  COMP_CRC32C(crc, (char *) record, offsetof(XLogRecord, xl_crc));
737  FIN_CRC32C(crc);
738 
739  if (!EQ_CRC32C(record->xl_crc, crc))
740  {
741  report_invalid_record(state,
742  "incorrect resource manager data checksum in record at %X/%X",
743  (uint32) (recptr >> 32), (uint32) recptr);
744  return false;
745  }
746 
747  return true;
748 }
749 
750 /*
751  * Validate a page header.
752  *
753  * Check if 'phdr' is valid as the header of the XLog page at position
754  * 'recptr'.
755  */
756 bool
758  char *phdr)
759 {
760  XLogRecPtr recaddr;
761  XLogSegNo segno;
762  int32 offset;
763  XLogPageHeader hdr = (XLogPageHeader) phdr;
764 
765  Assert((recptr % XLOG_BLCKSZ) == 0);
766 
767  XLByteToSeg(recptr, segno, state->segcxt.ws_segsize);
768  offset = XLogSegmentOffset(recptr, state->segcxt.ws_segsize);
769 
770  XLogSegNoOffsetToRecPtr(segno, offset, state->segcxt.ws_segsize, recaddr);
771 
772  if (hdr->xlp_magic != XLOG_PAGE_MAGIC)
773  {
774  char fname[MAXFNAMELEN];
775 
776  XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
777 
778  report_invalid_record(state,
779  "invalid magic number %04X in log segment %s, offset %u",
780  hdr->xlp_magic,
781  fname,
782  offset);
783  return false;
784  }
785 
786  if ((hdr->xlp_info & ~XLP_ALL_FLAGS) != 0)
787  {
788  char fname[MAXFNAMELEN];
789 
790  XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
791 
792  report_invalid_record(state,
793  "invalid info bits %04X in log segment %s, offset %u",
794  hdr->xlp_info,
795  fname,
796  offset);
797  return false;
798  }
799 
800  if (hdr->xlp_info & XLP_LONG_HEADER)
801  {
802  XLogLongPageHeader longhdr = (XLogLongPageHeader) hdr;
803 
804  if (state->system_identifier &&
805  longhdr->xlp_sysid != state->system_identifier)
806  {
807  report_invalid_record(state,
808  "WAL file is from different database system: WAL file database system identifier is %llu, pg_control database system identifier is %llu",
809  (unsigned long long) longhdr->xlp_sysid,
810  (unsigned long long) state->system_identifier);
811  return false;
812  }
813  else if (longhdr->xlp_seg_size != state->segcxt.ws_segsize)
814  {
815  report_invalid_record(state,
816  "WAL file is from different database system: incorrect segment size in page header");
817  return false;
818  }
819  else if (longhdr->xlp_xlog_blcksz != XLOG_BLCKSZ)
820  {
821  report_invalid_record(state,
822  "WAL file is from different database system: incorrect XLOG_BLCKSZ in page header");
823  return false;
824  }
825  }
826  else if (offset == 0)
827  {
828  char fname[MAXFNAMELEN];
829 
830  XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
831 
832  /* hmm, first page of file doesn't have a long header? */
833  report_invalid_record(state,
834  "invalid info bits %04X in log segment %s, offset %u",
835  hdr->xlp_info,
836  fname,
837  offset);
838  return false;
839  }
840 
841  /*
842  * Check that the address on the page agrees with what we expected. This
843  * check typically fails when an old WAL segment is recycled, and hasn't
844  * yet been overwritten with new data yet.
845  */
846  if (hdr->xlp_pageaddr != recaddr)
847  {
848  char fname[MAXFNAMELEN];
849 
850  XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
851 
852  report_invalid_record(state,
853  "unexpected pageaddr %X/%X in log segment %s, offset %u",
854  (uint32) (hdr->xlp_pageaddr >> 32), (uint32) hdr->xlp_pageaddr,
855  fname,
856  offset);
857  return false;
858  }
859 
860  /*
861  * Since child timelines are always assigned a TLI greater than their
862  * immediate parent's TLI, we should never see TLI go backwards across
863  * successive pages of a consistent WAL sequence.
864  *
865  * Sometimes we re-read a segment that's already been (partially) read. So
866  * we only verify TLIs for pages that are later than the last remembered
867  * LSN.
868  */
869  if (recptr > state->latestPagePtr)
870  {
871  if (hdr->xlp_tli < state->latestPageTLI)
872  {
873  char fname[MAXFNAMELEN];
874 
875  XLogFileName(fname, state->seg.ws_tli, segno, state->segcxt.ws_segsize);
876 
877  report_invalid_record(state,
878  "out-of-sequence timeline ID %u (after %u) in log segment %s, offset %u",
879  hdr->xlp_tli,
880  state->latestPageTLI,
881  fname,
882  offset);
883  return false;
884  }
885  }
886  state->latestPagePtr = recptr;
887  state->latestPageTLI = hdr->xlp_tli;
888 
889  return true;
890 }
891 
892 #ifdef FRONTEND
893 /*
894  * Functions that are currently not needed in the backend, but are better
895  * implemented inside xlogreader.c because of the internal facilities available
896  * here.
897  */
898 
899 /*
900  * Find the first record with an lsn >= RecPtr.
901  *
902  * Useful for checking whether RecPtr is a valid xlog address for reading, and
903  * to find the first valid address after some address when dumping records for
904  * debugging purposes.
905  */
907 XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr)
908 {
909  XLogReaderState saved_state = *state;
910  XLogRecPtr tmpRecPtr;
913  char *errormsg;
914 
915  Assert(!XLogRecPtrIsInvalid(RecPtr));
916 
917  /*
918  * skip over potential continuation data, keeping in mind that it may span
919  * multiple pages
920  */
921  tmpRecPtr = RecPtr;
922  while (true)
923  {
924  XLogRecPtr targetPagePtr;
925  int targetRecOff;
926  uint32 pageHeaderSize;
927  int readLen;
928 
929  /*
930  * Compute targetRecOff. It should typically be equal or greater than
931  * short page-header since a valid record can't start anywhere before
932  * that, except when caller has explicitly specified the offset that
933  * falls somewhere there or when we are skipping multi-page
934  * continuation record. It doesn't matter though because
935  * ReadPageInternal() is prepared to handle that and will read at
936  * least short page-header worth of data
937  */
938  targetRecOff = tmpRecPtr % XLOG_BLCKSZ;
939 
940  /* scroll back to page boundary */
941  targetPagePtr = tmpRecPtr - targetRecOff;
942 
943  /* Read the page containing the record */
944  readLen = ReadPageInternal(state, targetPagePtr, targetRecOff);
945  if (readLen < 0)
946  goto err;
947 
948  header = (XLogPageHeader) state->readBuf;
949 
950  pageHeaderSize = XLogPageHeaderSize(header);
951 
952  /* make sure we have enough data for the page header */
953  readLen = ReadPageInternal(state, targetPagePtr, pageHeaderSize);
954  if (readLen < 0)
955  goto err;
956 
957  /* skip over potential continuation data */
958  if (header->xlp_info & XLP_FIRST_IS_CONTRECORD)
959  {
960  /*
961  * If the length of the remaining continuation data is more than
962  * what can fit in this page, the continuation record crosses over
963  * this page. Read the next page and try again. xlp_rem_len in the
964  * next page header will contain the remaining length of the
965  * continuation data
966  *
967  * Note that record headers are MAXALIGN'ed
968  */
969  if (MAXALIGN(header->xlp_rem_len) > (XLOG_BLCKSZ - pageHeaderSize))
970  tmpRecPtr = targetPagePtr + XLOG_BLCKSZ;
971  else
972  {
973  /*
974  * The previous continuation record ends in this page. Set
975  * tmpRecPtr to point to the first valid record
976  */
977  tmpRecPtr = targetPagePtr + pageHeaderSize
978  + MAXALIGN(header->xlp_rem_len);
979  break;
980  }
981  }
982  else
983  {
984  tmpRecPtr = targetPagePtr + pageHeaderSize;
985  break;
986  }
987  }
988 
989  /*
990  * we know now that tmpRecPtr is an address pointing to a valid XLogRecord
991  * because either we're at the first record after the beginning of a page
992  * or we just jumped over the remaining data of a continuation.
993  */
994  while (XLogReadRecord(state, tmpRecPtr, &errormsg) != NULL)
995  {
996  /* continue after the record */
997  tmpRecPtr = InvalidXLogRecPtr;
998 
999  /* past the record we've found, break out */
1000  if (RecPtr <= state->ReadRecPtr)
1001  {
1002  found = state->ReadRecPtr;
1003  goto out;
1004  }
1005  }
1006 
1007 err:
1008 out:
1009  /* Reset state to what we had before finding the record */
1010  state->ReadRecPtr = saved_state.ReadRecPtr;
1011  state->EndRecPtr = saved_state.EndRecPtr;
1012  XLogReaderInvalReadState(state);
1013 
1014  return found;
1015 }
1016 
1017 #endif /* FRONTEND */
1018 
1019 /* ----------------------------------------
1020  * Functions for decoding the data and block references in a record.
1021  * ----------------------------------------
1022  */
1023 
1024 /* private function to reset the state between records */
1025 static void
1027 {
1028  int block_id;
1029 
1030  state->decoded_record = NULL;
1031 
1032  state->main_data_len = 0;
1033 
1034  for (block_id = 0; block_id <= state->max_block_id; block_id++)
1035  {
1036  state->blocks[block_id].in_use = false;
1037  state->blocks[block_id].has_image = false;
1038  state->blocks[block_id].has_data = false;
1039  state->blocks[block_id].apply_image = false;
1040  }
1041  state->max_block_id = -1;
1042 }
1043 
1044 /*
1045  * Decode the previously read record.
1046  *
1047  * On error, a human-readable error message is returned in *errormsg, and
1048  * the return value is false.
1049  */
1050 bool
1051 DecodeXLogRecord(XLogReaderState *state, XLogRecord *record, char **errormsg)
1052 {
1053  /*
1054  * read next _size bytes from record buffer, but check for overrun first.
1055  */
1056 #define COPY_HEADER_FIELD(_dst, _size) \
1057  do { \
1058  if (remaining < _size) \
1059  goto shortdata_err; \
1060  memcpy(_dst, ptr, _size); \
1061  ptr += _size; \
1062  remaining -= _size; \
1063  } while(0)
1064 
1065  char *ptr;
1066  uint32 remaining;
1067  uint32 datatotal;
1068  RelFileNode *rnode = NULL;
1069  uint8 block_id;
1070 
1071  ResetDecoder(state);
1072 
1073  state->decoded_record = record;
1075 
1076  ptr = (char *) record;
1077  ptr += SizeOfXLogRecord;
1078  remaining = record->xl_tot_len - SizeOfXLogRecord;
1079 
1080  /* Decode the headers */
1081  datatotal = 0;
1082  while (remaining > datatotal)
1083  {
1084  COPY_HEADER_FIELD(&block_id, sizeof(uint8));
1085 
1086  if (block_id == XLR_BLOCK_ID_DATA_SHORT)
1087  {
1088  /* XLogRecordDataHeaderShort */
1089  uint8 main_data_len;
1090 
1091  COPY_HEADER_FIELD(&main_data_len, sizeof(uint8));
1092 
1093  state->main_data_len = main_data_len;
1094  datatotal += main_data_len;
1095  break; /* by convention, the main data fragment is
1096  * always last */
1097  }
1098  else if (block_id == XLR_BLOCK_ID_DATA_LONG)
1099  {
1100  /* XLogRecordDataHeaderLong */
1101  uint32 main_data_len;
1102 
1103  COPY_HEADER_FIELD(&main_data_len, sizeof(uint32));
1104  state->main_data_len = main_data_len;
1105  datatotal += main_data_len;
1106  break; /* by convention, the main data fragment is
1107  * always last */
1108  }
1109  else if (block_id == XLR_BLOCK_ID_ORIGIN)
1110  {
1111  COPY_HEADER_FIELD(&state->record_origin, sizeof(RepOriginId));
1112  }
1113  else if (block_id <= XLR_MAX_BLOCK_ID)
1114  {
1115  /* XLogRecordBlockHeader */
1116  DecodedBkpBlock *blk;
1117  uint8 fork_flags;
1118 
1119  if (block_id <= state->max_block_id)
1120  {
1121  report_invalid_record(state,
1122  "out-of-order block_id %u at %X/%X",
1123  block_id,
1124  (uint32) (state->ReadRecPtr >> 32),
1125  (uint32) state->ReadRecPtr);
1126  goto err;
1127  }
1128  state->max_block_id = block_id;
1129 
1130  blk = &state->blocks[block_id];
1131  blk->in_use = true;
1132  blk->apply_image = false;
1133 
1134  COPY_HEADER_FIELD(&fork_flags, sizeof(uint8));
1135  blk->forknum = fork_flags & BKPBLOCK_FORK_MASK;
1136  blk->flags = fork_flags;
1137  blk->has_image = ((fork_flags & BKPBLOCK_HAS_IMAGE) != 0);
1138  blk->has_data = ((fork_flags & BKPBLOCK_HAS_DATA) != 0);
1139 
1140  COPY_HEADER_FIELD(&blk->data_len, sizeof(uint16));
1141  /* cross-check that the HAS_DATA flag is set iff data_length > 0 */
1142  if (blk->has_data && blk->data_len == 0)
1143  {
1144  report_invalid_record(state,
1145  "BKPBLOCK_HAS_DATA set, but no data included at %X/%X",
1146  (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
1147  goto err;
1148  }
1149  if (!blk->has_data && blk->data_len != 0)
1150  {
1151  report_invalid_record(state,
1152  "BKPBLOCK_HAS_DATA not set, but data length is %u at %X/%X",
1153  (unsigned int) blk->data_len,
1154  (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
1155  goto err;
1156  }
1157  datatotal += blk->data_len;
1158 
1159  if (blk->has_image)
1160  {
1161  COPY_HEADER_FIELD(&blk->bimg_len, sizeof(uint16));
1162  COPY_HEADER_FIELD(&blk->hole_offset, sizeof(uint16));
1163  COPY_HEADER_FIELD(&blk->bimg_info, sizeof(uint8));
1164 
1165  blk->apply_image = ((blk->bimg_info & BKPIMAGE_APPLY) != 0);
1166 
1167  if (blk->bimg_info & BKPIMAGE_IS_COMPRESSED)
1168  {
1169  if (blk->bimg_info & BKPIMAGE_HAS_HOLE)
1170  COPY_HEADER_FIELD(&blk->hole_length, sizeof(uint16));
1171  else
1172  blk->hole_length = 0;
1173  }
1174  else
1175  blk->hole_length = BLCKSZ - blk->bimg_len;
1176  datatotal += blk->bimg_len;
1177 
1178  /*
1179  * cross-check that hole_offset > 0, hole_length > 0 and
1180  * bimg_len < BLCKSZ if the HAS_HOLE flag is set.
1181  */
1182  if ((blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
1183  (blk->hole_offset == 0 ||
1184  blk->hole_length == 0 ||
1185  blk->bimg_len == BLCKSZ))
1186  {
1187  report_invalid_record(state,
1188  "BKPIMAGE_HAS_HOLE set, but hole offset %u length %u block image length %u at %X/%X",
1189  (unsigned int) blk->hole_offset,
1190  (unsigned int) blk->hole_length,
1191  (unsigned int) blk->bimg_len,
1192  (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
1193  goto err;
1194  }
1195 
1196  /*
1197  * cross-check that hole_offset == 0 and hole_length == 0 if
1198  * the HAS_HOLE flag is not set.
1199  */
1200  if (!(blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
1201  (blk->hole_offset != 0 || blk->hole_length != 0))
1202  {
1203  report_invalid_record(state,
1204  "BKPIMAGE_HAS_HOLE not set, but hole offset %u length %u at %X/%X",
1205  (unsigned int) blk->hole_offset,
1206  (unsigned int) blk->hole_length,
1207  (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
1208  goto err;
1209  }
1210 
1211  /*
1212  * cross-check that bimg_len < BLCKSZ if the IS_COMPRESSED
1213  * flag is set.
1214  */
1215  if ((blk->bimg_info & BKPIMAGE_IS_COMPRESSED) &&
1216  blk->bimg_len == BLCKSZ)
1217  {
1218  report_invalid_record(state,
1219  "BKPIMAGE_IS_COMPRESSED set, but block image length %u at %X/%X",
1220  (unsigned int) blk->bimg_len,
1221  (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
1222  goto err;
1223  }
1224 
1225  /*
1226  * cross-check that bimg_len = BLCKSZ if neither HAS_HOLE nor
1227  * IS_COMPRESSED flag is set.
1228  */
1229  if (!(blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
1230  !(blk->bimg_info & BKPIMAGE_IS_COMPRESSED) &&
1231  blk->bimg_len != BLCKSZ)
1232  {
1233  report_invalid_record(state,
1234  "neither BKPIMAGE_HAS_HOLE nor BKPIMAGE_IS_COMPRESSED set, but block image length is %u at %X/%X",
1235  (unsigned int) blk->data_len,
1236  (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
1237  goto err;
1238  }
1239  }
1240  if (!(fork_flags & BKPBLOCK_SAME_REL))
1241  {
1242  COPY_HEADER_FIELD(&blk->rnode, sizeof(RelFileNode));
1243  rnode = &blk->rnode;
1244  }
1245  else
1246  {
1247  if (rnode == NULL)
1248  {
1249  report_invalid_record(state,
1250  "BKPBLOCK_SAME_REL set but no previous rel at %X/%X",
1251  (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
1252  goto err;
1253  }
1254 
1255  blk->rnode = *rnode;
1256  }
1257  COPY_HEADER_FIELD(&blk->blkno, sizeof(BlockNumber));
1258  }
1259  else
1260  {
1261  report_invalid_record(state,
1262  "invalid block_id %u at %X/%X",
1263  block_id,
1264  (uint32) (state->ReadRecPtr >> 32),
1265  (uint32) state->ReadRecPtr);
1266  goto err;
1267  }
1268  }
1269 
1270  if (remaining != datatotal)
1271  goto shortdata_err;
1272 
1273  /*
1274  * Ok, we've parsed the fragment headers, and verified that the total
1275  * length of the payload in the fragments is equal to the amount of data
1276  * left. Copy the data of each fragment to a separate buffer.
1277  *
1278  * We could just set up pointers into readRecordBuf, but we want to align
1279  * the data for the convenience of the callers. Backup images are not
1280  * copied, however; they don't need alignment.
1281  */
1282 
1283  /* block data first */
1284  for (block_id = 0; block_id <= state->max_block_id; block_id++)
1285  {
1286  DecodedBkpBlock *blk = &state->blocks[block_id];
1287 
1288  if (!blk->in_use)
1289  continue;
1290 
1291  Assert(blk->has_image || !blk->apply_image);
1292 
1293  if (blk->has_image)
1294  {
1295  blk->bkp_image = ptr;
1296  ptr += blk->bimg_len;
1297  }
1298  if (blk->has_data)
1299  {
1300  if (!blk->data || blk->data_len > blk->data_bufsz)
1301  {
1302  if (blk->data)
1303  pfree(blk->data);
1304 
1305  /*
1306  * Force the initial request to be BLCKSZ so that we don't
1307  * waste time with lots of trips through this stanza as a
1308  * result of WAL compression.
1309  */
1310  blk->data_bufsz = MAXALIGN(Max(blk->data_len, BLCKSZ));
1311  blk->data = palloc(blk->data_bufsz);
1312  }
1313  memcpy(blk->data, ptr, blk->data_len);
1314  ptr += blk->data_len;
1315  }
1316  }
1317 
1318  /* and finally, the main data */
1319  if (state->main_data_len > 0)
1320  {
1321  if (!state->main_data || state->main_data_len > state->main_data_bufsz)
1322  {
1323  if (state->main_data)
1324  pfree(state->main_data);
1325 
1326  /*
1327  * main_data_bufsz must be MAXALIGN'ed. In many xlog record
1328  * types, we omit trailing struct padding on-disk to save a few
1329  * bytes; but compilers may generate accesses to the xlog struct
1330  * that assume that padding bytes are present. If the palloc
1331  * request is not large enough to include such padding bytes then
1332  * we'll get valgrind complaints due to otherwise-harmless fetches
1333  * of the padding bytes.
1334  *
1335  * In addition, force the initial request to be reasonably large
1336  * so that we don't waste time with lots of trips through this
1337  * stanza. BLCKSZ / 2 seems like a good compromise choice.
1338  */
1339  state->main_data_bufsz = MAXALIGN(Max(state->main_data_len,
1340  BLCKSZ / 2));
1341  state->main_data = palloc(state->main_data_bufsz);
1342  }
1343  memcpy(state->main_data, ptr, state->main_data_len);
1344  ptr += state->main_data_len;
1345  }
1346 
1347  return true;
1348 
1349 shortdata_err:
1350  report_invalid_record(state,
1351  "record with invalid length at %X/%X",
1352  (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
1353 err:
1354  *errormsg = state->errormsg_buf;
1355 
1356  return false;
1357 }
1358 
1359 /*
1360  * Returns information about the block that a block reference refers to.
1361  *
1362  * If the WAL record contains a block reference with the given ID, *rnode,
1363  * *forknum, and *blknum are filled in (if not NULL), and returns true.
1364  * Otherwise returns false.
1365  */
1366 bool
1368  RelFileNode *rnode, ForkNumber *forknum, BlockNumber *blknum)
1369 {
1370  DecodedBkpBlock *bkpb;
1371 
1372  if (!record->blocks[block_id].in_use)
1373  return false;
1374 
1375  bkpb = &record->blocks[block_id];
1376  if (rnode)
1377  *rnode = bkpb->rnode;
1378  if (forknum)
1379  *forknum = bkpb->forknum;
1380  if (blknum)
1381  *blknum = bkpb->blkno;
1382  return true;
1383 }
1384 
1385 /*
1386  * Returns the data associated with a block reference, or NULL if there is
1387  * no data (e.g. because a full-page image was taken instead). The returned
1388  * pointer points to a MAXALIGNed buffer.
1389  */
1390 char *
1392 {
1393  DecodedBkpBlock *bkpb;
1394 
1395  if (!record->blocks[block_id].in_use)
1396  return NULL;
1397 
1398  bkpb = &record->blocks[block_id];
1399 
1400  if (!bkpb->has_data)
1401  {
1402  if (len)
1403  *len = 0;
1404  return NULL;
1405  }
1406  else
1407  {
1408  if (len)
1409  *len = bkpb->data_len;
1410  return bkpb->data;
1411  }
1412 }
1413 
1414 /*
1415  * Restore a full-page image from a backup block attached to an XLOG record.
1416  *
1417  * Returns the buffer number containing the page.
1418  */
1419 bool
1420 RestoreBlockImage(XLogReaderState *record, uint8 block_id, char *page)
1421 {
1422  DecodedBkpBlock *bkpb;
1423  char *ptr;
1424  PGAlignedBlock tmp;
1425 
1426  if (!record->blocks[block_id].in_use)
1427  return false;
1428  if (!record->blocks[block_id].has_image)
1429  return false;
1430 
1431  bkpb = &record->blocks[block_id];
1432  ptr = bkpb->bkp_image;
1433 
1434  if (bkpb->bimg_info & BKPIMAGE_IS_COMPRESSED)
1435  {
1436  /* If a backup block image is compressed, decompress it */
1437  if (pglz_decompress(ptr, bkpb->bimg_len, tmp.data,
1438  BLCKSZ - bkpb->hole_length, true) < 0)
1439  {
1440  report_invalid_record(record, "invalid compressed image at %X/%X, block %d",
1441  (uint32) (record->ReadRecPtr >> 32),
1442  (uint32) record->ReadRecPtr,
1443  block_id);
1444  return false;
1445  }
1446  ptr = tmp.data;
1447  }
1448 
1449  /* generate page, taking into account hole if necessary */
1450  if (bkpb->hole_length == 0)
1451  {
1452  memcpy(page, ptr, BLCKSZ);
1453  }
1454  else
1455  {
1456  memcpy(page, ptr, bkpb->hole_offset);
1457  /* must zero-fill the hole */
1458  MemSet(page + bkpb->hole_offset, 0, bkpb->hole_length);
1459  memcpy(page + (bkpb->hole_offset + bkpb->hole_length),
1460  ptr + bkpb->hole_offset,
1461  BLCKSZ - (bkpb->hole_offset + bkpb->hole_length));
1462  }
1463 
1464  return true;
1465 }
1466 
1467 #ifndef FRONTEND
1468 
1469 /*
1470  * Extract the FullTransactionId from a WAL record.
1471  */
1474 {
1475  TransactionId xid,
1476  next_xid;
1477  uint32 epoch;
1478 
1479  /*
1480  * This function is only safe during replay, because it depends on the
1481  * replay state. See AdvanceNextFullTransactionIdPastXid() for more.
1482  */
1484 
1485  xid = XLogRecGetXid(record);
1488 
1489  /*
1490  * If xid is numerically greater than next_xid, it has to be from the
1491  * last epoch.
1492  */
1493  if (unlikely(xid > next_xid))
1494  --epoch;
1495 
1496  return FullTransactionIdFromEpochAndXid(epoch, xid);
1497 }
1498 
1499 #endif
int remaining
Definition: informix.c:687
BlockNumber blkno
Definition: xlogreader.h:67
#define INIT_CRC32C(crc)
Definition: pg_crc32c.h:41
#define AmStartupProcess()
Definition: miscadmin.h:412
XLogRecPtr xl_prev
Definition: xlogrecord.h:45
char ws_dir[MAXPGPATH]
Definition: xlogreader.h:46
#define InvalidXLogRecPtr
Definition: xlogdefs.h:28
#define BKPIMAGE_HAS_HOLE
Definition: xlogrecord.h:146
XLogPageReadCB read_page
Definition: xlogreader.h:115
char * readRecordBuf
Definition: xlogreader.h:204
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Definition: xlog.c:112
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Definition: c.h:507
#define XLogPageHeaderSize(hdr)
Definition: xlog_internal.h:85
#define XLR_BLOCK_ID_DATA_LONG
Definition: xlogrecord.h:224
static XLogRecPtr ReadRecPtr
Definition: xlog.c:825
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Definition: pg_crc32c.h:38
#define Min(x, y)
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Definition: xlogdefs.h:58
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Definition: mcxt.c:1013
static void report_invalid_record(XLogReaderState *state, const char *fmt,...) pg_attribute_printf(2
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void WALOpenSegmentInit(WALOpenSegment *seg, WALSegmentContext *segcxt, int segsize, const char *waldir)
Definition: xlogreader.c:207
#define MCXT_ALLOC_NO_OOM
Definition: fe_memutils.h:18
#define MemSet(start, val, len)
Definition: c.h:955
RmgrId xl_rmid
Definition: xlogrecord.h:47
XLogPageHeaderData * XLogPageHeader
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Definition: block.h:31
FullTransactionId nextFullXid
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Definition: xlogreader.h:78
bool DecodeXLogRecord(XLogReaderState *state, XLogRecord *record, char **errormsg)
Definition: xlogreader.c:1051
static int ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
Definition: xlogreader.c:546
int32 pglz_decompress(const char *source, int32 slen, char *dest, int32 rawsize, bool check_complete)
#define MAX_ERRORMSG_LEN
Definition: xlogreader.c:47
XLogRecord * XLogReadRecord(XLogReaderState *state, XLogRecPtr RecPtr, char **errormsg)
Definition: xlogreader.c:237
signed int int32
Definition: c.h:346
bool XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr, char *phdr)
Definition: xlogreader.c:757
#define pg_attribute_printf(f, a)
Definition: c.h:132
XLogRecPtr EndRecPtr
Definition: xlogreader.h:133
#define XidFromFullTransactionId(x)
Definition: transam.h:48
XLogLongPageHeaderData * XLogLongPageHeader
Definition: xlog_internal.h:74
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Definition: xlogreader.h:170
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Definition: c.h:1060
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Definition: c.h:357
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Definition: mcxt.c:1056
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Definition: xlogreader.h:176
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Definition: xlog.c:792
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Definition: xlogreader.h:77
static void XLogReaderInvalReadState(XLogReaderState *state)
Definition: xlogreader.c:645
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Definition: xlogrecord.h:43
#define XLOG_PAGE_MAGIC
Definition: xlog_internal.h:34
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Definition: xlogreader.h:146
#define vsnprintf
Definition: port.h:191
#define MAXPGPATH
static void static bool allocate_recordbuf(XLogReaderState *state, uint32 reclength)
Definition: xlogreader.c:164
#define BKPIMAGE_APPLY
Definition: xlogrecord.h:148
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Definition: globals.c:109
uint64 XLogSegNo
Definition: xlogdefs.h:41
XLogRecPtr ReadRecPtr
Definition: xlogreader.h:132
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Definition: xlogreader.h:143
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Definition: xlogreader.h:38
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Definition: varsup.c:34
#define COPY_HEADER_FIELD(_dst, _size)
unsigned int uint32
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#define EQ_CRC32C(c1, c2)
Definition: pg_crc32c.h:42
#define AllocSizeIsValid(size)
Definition: memutils.h:42
ForkNumber
Definition: relpath.h:40
TimeLineID xlp_tli
Definition: xlog_internal.h:40
#define XLR_MAX_BLOCK_ID
Definition: xlogrecord.h:221
XLogRecPtr xlp_pageaddr
Definition: xlog_internal.h:41
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
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Definition: xlogreader.h:205
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Definition: xlogrecord.h:55
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Definition: xlogreader.c:133
#define MAXFNAMELEN
#define RM_MAX_ID
Definition: rmgr.h:33
bool XLogRecGetBlockTag(XLogReaderState *record, uint8 block_id, RelFileNode *rnode, ForkNumber *forknum, BlockNumber *blknum)
Definition: xlogreader.c:1367
#define XLogRecGetXid(decoder)
Definition: xlogreader.h:244
char * XLogRecGetBlockData(XLogReaderState *record, uint8 block_id, Size *len)
Definition: xlogreader.c:1391
#define BKPBLOCK_SAME_REL
Definition: xlogrecord.h:183
#define BKPIMAGE_IS_COMPRESSED
Definition: xlogrecord.h:147
#define BKPBLOCK_HAS_IMAGE
Definition: xlogrecord.h:180
#define XLogSegmentOffset(xlogptr, wal_segsz_bytes)
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Definition: xlogreader.h:66
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Definition: transam.h:47
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Definition: xlog_internal.h:83
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Definition: xlogreader.h:84
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Definition: xlogreader.h:180
#define Max(x, y)
Definition: c.h:898
#define XLogSegNoOffsetToRecPtr(segno, offset, wal_segsz_bytes, dest)
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Definition: xlogdefs.h:21
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Definition: c.h:732
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Definition: xlogrecord.h:62
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Definition: xlog_internal.h:79
Definition: regguts.h:298
static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr, XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess)
Definition: xlogreader.c:659
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#define MCXT_ALLOC_ZERO
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#define SizeOfXLogShortPHD
Definition: xlog_internal.h:55
size_t Size
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#define XLogFileName(fname, tli, logSegNo, wal_segsz_bytes)
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Definition: xlogrecord.h:46
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Definition: xlogreader.c:1473
#define XLR_BLOCK_ID_ORIGIN
Definition: xlogrecord.h:225
#define XLP_FIRST_IS_CONTRECORD
Definition: xlog_internal.h:77
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Definition: transam.h:65
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Definition: c.h:685
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Definition: xlogreader.h:40
#define InvalidRepOriginId
Definition: origin.h:33
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Definition: xlogreader.h:75
bool RestoreBlockImage(XLogReaderState *record, uint8 block_id, char *page)
Definition: xlogreader.c:1420
#define XLR_BLOCK_ID_DATA_SHORT
Definition: xlogrecord.h:223
XLogReaderState * XLogReaderAllocate(int wal_segment_size, const char *waldir, XLogPageReadCB pagereadfunc, void *private_data)
Definition: xlogreader.c:71
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Definition: xlogreader.h:147
static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr)
Definition: xlogreader.c:728
#define BKPBLOCK_FORK_MASK
Definition: xlogrecord.h:178
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Definition: mcxt.c:949
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Definition: gettimeofday.c:34
#define unlikely(x)
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Definition: xlogreader.h:121
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Definition: xlogreader.h:169
int(* XLogPageReadCB)(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen, XLogRecPtr targetRecPtr, char *readBuf)
Definition: xlogreader.h:53
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Definition: xlogreader.h:208
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Definition: xlogreader.h:39
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Definition: xlogreader.h:145
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Definition: pg_crc32c.h:89
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Definition: xlogreader.h:177
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Definition: xlogreader.h:65
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Definition: pg_crc32c.h:94
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Definition: port.h:192
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#define _(x)
Definition: elog.c:84
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Definition: xlogreader.h:149
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Definition: xlogreader.c:1026
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Definition: c.h:655
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Definition: xlogreader.h:152
#define BKPBLOCK_HAS_DATA
Definition: xlogrecord.h:181
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