#include "postgres.h"
#include "access/transam.h"
#include "access/xlogrecord.h"
#include "access/xlog_internal.h"
#include "access/xlogreader.h"
#include "catalog/pg_control.h"
#include "common/pg_lzcompress.h"
#include "replication/origin.h"

Include dependency graph for xlogreader.c:

Macros
#define	MAX_ERRORMSG_LEN 1000

#define	COPY_HEADER_FIELD(_dst, _size)

Functions
static bool	allocate_recordbuf (XLogReaderState *state, uint32 reclength)

static bool	ValidXLogPageHeader (XLogReaderState *state, XLogRecPtr recptr, XLogPageHeader hdr)

static bool	ValidXLogRecordHeader (XLogReaderState state, XLogRecPtr RecPtr, XLogRecPtr PrevRecPtr, XLogRecord record, bool randAccess)

static bool	ValidXLogRecord (XLogReaderState state, XLogRecord record, XLogRecPtr recptr)

static int	ReadPageInternal (XLogReaderState *state, XLogRecPtr pageptr, int reqLen)

static void	report_invalid_record (XLogReaderState state, const char fmt,...) pg_attribute_printf(2

static void static void	ResetDecoder (XLogReaderState *state)

XLogReaderState *	XLogReaderAllocate (XLogPageReadCB pagereadfunc, void *private_data)

void	XLogReaderFree (XLogReaderState *state)

XLogRecord *	XLogReadRecord (XLogReaderState state, XLogRecPtr RecPtr, char *errormsg)

void	XLogReaderInvalReadState (XLogReaderState *state)

bool	DecodeXLogRecord (XLogReaderState state, XLogRecord record, char **errormsg)

bool	XLogRecGetBlockTag (XLogReaderState record, uint8 block_id, RelFileNode rnode, ForkNumber forknum, BlockNumber blknum)

char *	XLogRecGetBlockData (XLogReaderState record, uint8 block_id, Size len)

bool	RestoreBlockImage (XLogReaderState record, uint8 block_id, char page)

Macro Definition Documentation

#define COPY_HEADER_FIELD	(	_dst,
		_size
	)

Value:

do {                                        \
        if (remaining < _size)                  \
            goto shortdata_err;                 \
        memcpy(_dst, ptr, _size);               \
        ptr += _size;                           \
		remaining -= _size;                       \
    } while(0)

Referenced by DecodeXLogRecord().

#define MAX_ERRORMSG_LEN 1000

Definition at line 43 of file xlogreader.c.

Referenced by report_invalid_record(), and XLogReaderAllocate().

Function Documentation

static bool allocate_recordbuf	(	XLogReaderState *	state,
		uint32	reclength
	)

static

Definition at line 156 of file xlogreader.c.

References Max, MCXT_ALLOC_NO_OOM, NULL, palloc_extended(), pfree(), XLogReaderState::readRecordBuf, and XLogReaderState::readRecordBufSize.

Referenced by XLogReaderAllocate(), and XLogReadRecord().

 {
     uint32      newSize = reclength;
 
     newSize += XLOG_BLCKSZ - (newSize % XLOG_BLCKSZ);
     newSize = Max(newSize, 5 * Max(BLCKSZ, XLOG_BLCKSZ));
 
     if (state->readRecordBuf)
         pfree(state->readRecordBuf);
     state->readRecordBuf =
         (char *) palloc_extended(newSize, MCXT_ALLOC_NO_OOM);
     if (state->readRecordBuf == NULL)
     {
         state->readRecordBufSize = 0;
         return false;
     }
     state->readRecordBufSize = newSize;
     return true;
 }

bool DecodeXLogRecord	(	XLogReaderState *	state,
		XLogRecord *	record,
		char **	errormsg
	)

Definition at line 1012 of file xlogreader.c.

References DecodedBkpBlock::apply_image, Assert, DecodedBkpBlock::bimg_info, DecodedBkpBlock::bimg_len, DecodedBkpBlock::bkp_image, BKPBLOCK_FORK_MASK, BKPBLOCK_HAS_DATA, BKPBLOCK_HAS_IMAGE, BKPBLOCK_SAME_REL, BKPIMAGE_APPLY, BKPIMAGE_HAS_HOLE, BKPIMAGE_IS_COMPRESSED, DecodedBkpBlock::blkno, XLogReaderState::blocks, COPY_HEADER_FIELD, DecodedBkpBlock::data, DecodedBkpBlock::data_bufsz, DecodedBkpBlock::data_len, XLogReaderState::decoded_record, XLogReaderState::errormsg_buf, DecodedBkpBlock::flags, DecodedBkpBlock::forknum, DecodedBkpBlock::has_data, DecodedBkpBlock::has_image, DecodedBkpBlock::hole_length, DecodedBkpBlock::hole_offset, DecodedBkpBlock::in_use, InvalidRepOriginId, XLogReaderState::main_data, XLogReaderState::main_data_bufsz, XLogReaderState::main_data_len, XLogReaderState::max_block_id, NULL, palloc(), pfree(), XLogReaderState::ReadRecPtr, XLogReaderState::record_origin, remaining, report_invalid_record(), ResetDecoder(), DecodedBkpBlock::rnode, SizeOfXLogRecord, XLogRecord::xl_tot_len, XLR_BLOCK_ID_DATA_LONG, XLR_BLOCK_ID_DATA_SHORT, XLR_BLOCK_ID_ORIGIN, and XLR_MAX_BLOCK_ID.

Referenced by XLogInsertRecord(), and XLogReadRecord().

 {
     /*
      * read next _size bytes from record buffer, but check for overrun first.
      */
 #define COPY_HEADER_FIELD(_dst, _size)          \
     do {                                        \
         if (remaining < _size)                  \
             goto shortdata_err;                 \
         memcpy(_dst, ptr, _size);               \
         ptr += _size;                           \
         remaining -= _size;                     \
     } while(0)
 
     char       *ptr;
     uint32      remaining;
     uint32      datatotal;
     RelFileNode *rnode = NULL;
     uint8       block_id;
 
     ResetDecoder(state);
 
     state->decoded_record = record;
     state->record_origin = InvalidRepOriginId;
 
     ptr = (char *) record;
     ptr += SizeOfXLogRecord;
     remaining = record->xl_tot_len - SizeOfXLogRecord;
 
     /* Decode the headers */
     datatotal = 0;
     while (remaining > datatotal)
     {
         COPY_HEADER_FIELD(&block_id, sizeof(uint8));
 
         if (block_id == XLR_BLOCK_ID_DATA_SHORT)
         {
             /* XLogRecordDataHeaderShort */
             uint8       main_data_len;
 
             COPY_HEADER_FIELD(&main_data_len, sizeof(uint8));
 
             state->main_data_len = main_data_len;
             datatotal += main_data_len;
             break;              /* by convention, the main data fragment is
                                  * always last */
         }
         else if (block_id == XLR_BLOCK_ID_DATA_LONG)
         {
             /* XLogRecordDataHeaderLong */
             uint32      main_data_len;
 
             COPY_HEADER_FIELD(&main_data_len, sizeof(uint32));
             state->main_data_len = main_data_len;
             datatotal += main_data_len;
             break;              /* by convention, the main data fragment is
                                  * always last */
         }
         else if (block_id == XLR_BLOCK_ID_ORIGIN)
         {
             COPY_HEADER_FIELD(&state->record_origin, sizeof(RepOriginId));
         }
         else if (block_id <= XLR_MAX_BLOCK_ID)
         {
             /* XLogRecordBlockHeader */
             DecodedBkpBlock *blk;
             uint8       fork_flags;
 
             if (block_id <= state->max_block_id)
             {
                 report_invalid_record(state,
                                       "out-of-order block_id %u at %X/%X",
                                       block_id,
                                       (uint32) (state->ReadRecPtr >> 32),
                                       (uint32) state->ReadRecPtr);
                 goto err;
             }
             state->max_block_id = block_id;
 
             blk = &state->blocks[block_id];
             blk->in_use = true;
             blk->apply_image = false;
 
             COPY_HEADER_FIELD(&fork_flags, sizeof(uint8));
             blk->forknum = fork_flags & BKPBLOCK_FORK_MASK;
             blk->flags = fork_flags;
             blk->has_image = ((fork_flags & BKPBLOCK_HAS_IMAGE) != 0);
             blk->has_data = ((fork_flags & BKPBLOCK_HAS_DATA) != 0);
 
             COPY_HEADER_FIELD(&blk->data_len, sizeof(uint16));
             /* cross-check that the HAS_DATA flag is set iff data_length > 0 */
             if (blk->has_data && blk->data_len == 0)
             {
                 report_invalid_record(state,
                                       "BKPBLOCK_HAS_DATA set, but no data included at %X/%X",
                                       (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
                 goto err;
             }
             if (!blk->has_data && blk->data_len != 0)
             {
                 report_invalid_record(state,
                                       "BKPBLOCK_HAS_DATA not set, but data length is %u at %X/%X",
                                       (unsigned int) blk->data_len,
                                       (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
                 goto err;
             }
             datatotal += blk->data_len;
 
             if (blk->has_image)
             {
                 COPY_HEADER_FIELD(&blk->bimg_len, sizeof(uint16));
                 COPY_HEADER_FIELD(&blk->hole_offset, sizeof(uint16));
                 COPY_HEADER_FIELD(&blk->bimg_info, sizeof(uint8));
 
                 blk->apply_image = ((blk->bimg_info & BKPIMAGE_APPLY) != 0);
 
                 if (blk->bimg_info & BKPIMAGE_IS_COMPRESSED)
                 {
                     if (blk->bimg_info & BKPIMAGE_HAS_HOLE)
                         COPY_HEADER_FIELD(&blk->hole_length, sizeof(uint16));
                     else
                         blk->hole_length = 0;
                 }
                 else
                     blk->hole_length = BLCKSZ - blk->bimg_len;
                 datatotal += blk->bimg_len;
 
                 /*
                  * cross-check that hole_offset > 0, hole_length > 0 and
                  * bimg_len < BLCKSZ if the HAS_HOLE flag is set.
                  */
                 if ((blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
                     (blk->hole_offset == 0 ||
                      blk->hole_length == 0 ||
                      blk->bimg_len == BLCKSZ))
                 {
                     report_invalid_record(state,
                                           "BKPIMAGE_HAS_HOLE set, but hole offset %u length %u block image length %u at %X/%X",
                                           (unsigned int) blk->hole_offset,
                                           (unsigned int) blk->hole_length,
                                           (unsigned int) blk->bimg_len,
                                           (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
                     goto err;
                 }
 
                 /*
                  * cross-check that hole_offset == 0 and hole_length == 0 if
                  * the HAS_HOLE flag is not set.
                  */
                 if (!(blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
                     (blk->hole_offset != 0 || blk->hole_length != 0))
                 {
                     report_invalid_record(state,
                                           "BKPIMAGE_HAS_HOLE not set, but hole offset %u length %u at %X/%X",
                                           (unsigned int) blk->hole_offset,
                                           (unsigned int) blk->hole_length,
                                           (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
                     goto err;
                 }
 
                 /*
                  * cross-check that bimg_len < BLCKSZ if the IS_COMPRESSED
                  * flag is set.
                  */
                 if ((blk->bimg_info & BKPIMAGE_IS_COMPRESSED) &&
                     blk->bimg_len == BLCKSZ)
                 {
                     report_invalid_record(state,
                                           "BKPIMAGE_IS_COMPRESSED set, but block image length %u at %X/%X",
                                           (unsigned int) blk->bimg_len,
                                           (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
                     goto err;
                 }
 
                 /*
                  * cross-check that bimg_len = BLCKSZ if neither HAS_HOLE nor
                  * IS_COMPRESSED flag is set.
                  */
                 if (!(blk->bimg_info & BKPIMAGE_HAS_HOLE) &&
                     !(blk->bimg_info & BKPIMAGE_IS_COMPRESSED) &&
                     blk->bimg_len != BLCKSZ)
                 {
                     report_invalid_record(state,
                                           "neither BKPIMAGE_HAS_HOLE nor BKPIMAGE_IS_COMPRESSED set, but block image length is %u at %X/%X",
                                           (unsigned int) blk->data_len,
                                           (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
                     goto err;
                 }
             }
             if (!(fork_flags & BKPBLOCK_SAME_REL))
             {
                 COPY_HEADER_FIELD(&blk->rnode, sizeof(RelFileNode));
                 rnode = &blk->rnode;
             }
             else
             {
                 if (rnode == NULL)
                 {
                     report_invalid_record(state,
                                           "BKPBLOCK_SAME_REL set but no previous rel at %X/%X",
                                           (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
                     goto err;
                 }
 
                 blk->rnode = *rnode;
             }
             COPY_HEADER_FIELD(&blk->blkno, sizeof(BlockNumber));
         }
         else
         {
             report_invalid_record(state,
                                   "invalid block_id %u at %X/%X",
                                   block_id,
                                   (uint32) (state->ReadRecPtr >> 32),
                                   (uint32) state->ReadRecPtr);
             goto err;
         }
     }
 
     if (remaining != datatotal)
         goto shortdata_err;
 
     /*
      * Ok, we've parsed the fragment headers, and verified that the total
      * length of the payload in the fragments is equal to the amount of data
      * left. Copy the data of each fragment to a separate buffer.
      *
      * We could just set up pointers into readRecordBuf, but we want to align
      * the data for the convenience of the callers. Backup images are not
      * copied, however; they don't need alignment.
      */
 
     /* block data first */
     for (block_id = 0; block_id <= state->max_block_id; block_id++)
     {
         DecodedBkpBlock *blk = &state->blocks[block_id];
 
         if (!blk->in_use)
             continue;
 
         Assert(blk->has_image || !blk->apply_image);
 
         if (blk->has_image)
         {
             blk->bkp_image = ptr;
             ptr += blk->bimg_len;
         }
         if (blk->has_data)
         {
             if (!blk->data || blk->data_len > blk->data_bufsz)
             {
                 if (blk->data)
                     pfree(blk->data);
                 blk->data_bufsz = blk->data_len;
                 blk->data = palloc(blk->data_bufsz);
             }
             memcpy(blk->data, ptr, blk->data_len);
             ptr += blk->data_len;
         }
     }
 
     /* and finally, the main data */
     if (state->main_data_len > 0)
     {
         if (!state->main_data || state->main_data_len > state->main_data_bufsz)
         {
             if (state->main_data)
                 pfree(state->main_data);
             state->main_data_bufsz = state->main_data_len;
             state->main_data = palloc(state->main_data_bufsz);
         }
         memcpy(state->main_data, ptr, state->main_data_len);
         ptr += state->main_data_len;
     }
 
     return true;
 
 shortdata_err:
     report_invalid_record(state,
                           "record with invalid length at %X/%X",
                           (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr);
 err:
     *errormsg = state->errormsg_buf;
 
     return false;
 }

static int ReadPageInternal	(	XLogReaderState *	state,
		XLogRecPtr	pageptr,
		int	reqLen
	)

static

Definition at line 503 of file xlogreader.c.

References Assert, XLogReaderState::currRecPtr, Max, XLogReaderState::read_page, XLogReaderState::readBuf, XLogReaderState::readLen, readLen, XLogReaderState::readOff, XLogReaderState::readPageTLI, XLogReaderState::readSegNo, SizeOfXLogShortPHD, ValidXLogPageHeader(), XLByteToSeg, XLogPageHeaderSize, XLogReaderInvalReadState(), and XLogSegSize.

Referenced by XLogReadRecord().

 {
     int         readLen;
     uint32      targetPageOff;
     XLogSegNo   targetSegNo;
     XLogPageHeader hdr;
 
     Assert((pageptr % XLOG_BLCKSZ) == 0);
 
     XLByteToSeg(pageptr, targetSegNo);
     targetPageOff = (pageptr % XLogSegSize);
 
     /* check whether we have all the requested data already */
     if (targetSegNo == state->readSegNo && targetPageOff == state->readOff &&
         reqLen < state->readLen)
         return state->readLen;
 
     /*
      * Data is not in our buffer.
      *
      * Every time we actually read the page, even if we looked at parts of it
      * before, we need to do verification as the read_page callback might now
      * be rereading data from a different source.
      *
      * Whenever switching to a new WAL segment, we read the first page of the
      * file and validate its header, even if that's not where the target
      * record is.  This is so that we can check the additional identification
      * info that is present in the first page's "long" header.
      */
     if (targetSegNo != state->readSegNo && targetPageOff != 0)
     {
         XLogPageHeader hdr;
         XLogRecPtr  targetSegmentPtr = pageptr - targetPageOff;
 
         readLen = state->read_page(state, targetSegmentPtr, XLOG_BLCKSZ,
                                    state->currRecPtr,
                                    state->readBuf, &state->readPageTLI);
         if (readLen < 0)
             goto err;
 
         /* we can be sure to have enough WAL available, we scrolled back */
         Assert(readLen == XLOG_BLCKSZ);
 
         hdr = (XLogPageHeader) state->readBuf;
 
         if (!ValidXLogPageHeader(state, targetSegmentPtr, hdr))
             goto err;
     }
 
     /*
      * First, read the requested data length, but at least a short page header
      * so that we can validate it.
      */
     readLen = state->read_page(state, pageptr, Max(reqLen, SizeOfXLogShortPHD),
                                state->currRecPtr,
                                state->readBuf, &state->readPageTLI);
     if (readLen < 0)
         goto err;
 
     Assert(readLen <= XLOG_BLCKSZ);
 
     /* Do we have enough data to check the header length? */
     if (readLen <= SizeOfXLogShortPHD)
         goto err;
 
     Assert(readLen >= reqLen);
 
     hdr = (XLogPageHeader) state->readBuf;
 
     /* still not enough */
     if (readLen < XLogPageHeaderSize(hdr))
     {
         readLen = state->read_page(state, pageptr, XLogPageHeaderSize(hdr),
                                    state->currRecPtr,
                                    state->readBuf, &state->readPageTLI);
         if (readLen < 0)
             goto err;
     }
 
     /*
      * Now that we know we have the full header, validate it.
      */
     if (!ValidXLogPageHeader(state, pageptr, hdr))
         goto err;
 
     /* update read state information */
     state->readSegNo = targetSegNo;
     state->readOff = targetPageOff;
     state->readLen = readLen;
 
     return readLen;
 
 err:
     XLogReaderInvalReadState(state);
     return -1;
 }

static void report_invalid_record	(	XLogReaderState *	state,
		const char *	fmt,
			...
	)

static

Definition at line 50 of file xlogreader.c.

References _, generate_unaccent_rules::args, XLogReaderState::errormsg_buf, MAX_ERRORMSG_LEN, and vsnprintf().

Referenced by DecodeXLogRecord(), RestoreBlockImage(), ValidXLogPageHeader(), ValidXLogRecord(), ValidXLogRecordHeader(), and XLogReadRecord().

 {
     va_list     args;
 
     fmt = _(fmt);
 
     va_start(args, fmt);
     vsnprintf(state->errormsg_buf, MAX_ERRORMSG_LEN, fmt, args);
     va_end(args);
 }

static void ResetDecoder ( XLogReaderState * state )

static

Definition at line 987 of file xlogreader.c.

References DecodedBkpBlock::apply_image, XLogReaderState::blocks, XLogReaderState::decoded_record, DecodedBkpBlock::has_data, DecodedBkpBlock::has_image, DecodedBkpBlock::in_use, XLogReaderState::main_data_len, XLogReaderState::max_block_id, and NULL.

Referenced by DecodeXLogRecord(), and XLogReadRecord().

 {
     int         block_id;
 
     state->decoded_record = NULL;
 
     state->main_data_len = 0;
 
     for (block_id = 0; block_id <= state->max_block_id; block_id++)
     {
         state->blocks[block_id].in_use = false;
         state->blocks[block_id].has_image = false;
         state->blocks[block_id].has_data = false;
         state->blocks[block_id].apply_image = false;
     }
     state->max_block_id = -1;
 }

bool RestoreBlockImage	(	XLogReaderState *	record,
		uint8	block_id,
		char *	page
	)

Definition at line 1360 of file xlogreader.c.

References DecodedBkpBlock::bimg_info, DecodedBkpBlock::bimg_len, DecodedBkpBlock::bkp_image, BKPIMAGE_IS_COMPRESSED, XLogReaderState::blocks, DecodedBkpBlock::has_image, DecodedBkpBlock::hole_length, DecodedBkpBlock::hole_offset, DecodedBkpBlock::in_use, MemSet, pglz_decompress(), XLogReaderState::ReadRecPtr, and report_invalid_record().

Referenced by checkXLogConsistency(), and XLogReadBufferForRedoExtended().

 {
     DecodedBkpBlock *bkpb;
     char       *ptr;
     char        tmp[BLCKSZ];
 
     if (!record->blocks[block_id].in_use)
         return false;
     if (!record->blocks[block_id].has_image)
         return false;
 
     bkpb = &record->blocks[block_id];
     ptr = bkpb->bkp_image;
 
     if (bkpb->bimg_info & BKPIMAGE_IS_COMPRESSED)
     {
         /* If a backup block image is compressed, decompress it */
         if (pglz_decompress(ptr, bkpb->bimg_len, tmp,
                             BLCKSZ - bkpb->hole_length) < 0)
         {
             report_invalid_record(record, "invalid compressed image at %X/%X, block %d",
                                   (uint32) (record->ReadRecPtr >> 32),
                                   (uint32) record->ReadRecPtr,
                                   block_id);
             return false;
         }
         ptr = tmp;
     }
 
     /* generate page, taking into account hole if necessary */
     if (bkpb->hole_length == 0)
     {
         memcpy(page, ptr, BLCKSZ);
     }
     else
     {
         memcpy(page, ptr, bkpb->hole_offset);
         /* must zero-fill the hole */
         MemSet(page + bkpb->hole_offset, 0, bkpb->hole_length);
         memcpy(page + (bkpb->hole_offset + bkpb->hole_length),
                ptr + bkpb->hole_offset,
                BLCKSZ - (bkpb->hole_offset + bkpb->hole_length));
     }
 
     return true;
 }

static bool ValidXLogPageHeader	(	XLogReaderState *	state,
		XLogRecPtr	recptr,
		XLogPageHeader	hdr
	)

static

Definition at line 713 of file xlogreader.c.

References Assert, XLogReaderState::latestPagePtr, XLogReaderState::latestPageTLI, MAXFNAMELEN, XLogReaderState::readPageTLI, report_invalid_record(), snprintf(), XLogReaderState::system_identifier, UINT64_FORMAT, XLByteToSeg, XLOG_PAGE_MAGIC, XLogFileName, XLogSegNoOffsetToRecPtr, XLogSegSize, XLP_ALL_FLAGS, XLogPageHeaderData::xlp_info, XLP_LONG_HEADER, XLogPageHeaderData::xlp_magic, XLogPageHeaderData::xlp_pageaddr, XLogLongPageHeaderData::xlp_seg_size, XLogLongPageHeaderData::xlp_sysid, XLogPageHeaderData::xlp_tli, and XLogLongPageHeaderData::xlp_xlog_blcksz.

Referenced by ReadPageInternal().

 {
     XLogRecPtr  recaddr;
     XLogSegNo   segno;
     int32       offset;
 
     Assert((recptr % XLOG_BLCKSZ) == 0);
 
     XLByteToSeg(recptr, segno);
     offset = recptr % XLogSegSize;
 
     XLogSegNoOffsetToRecPtr(segno, offset, recaddr);
 
     if (hdr->xlp_magic != XLOG_PAGE_MAGIC)
     {
         char        fname[MAXFNAMELEN];
 
         XLogFileName(fname, state->readPageTLI, segno);
 
         report_invalid_record(state,
                               "invalid magic number %04X in log segment %s, offset %u",
                               hdr->xlp_magic,
                               fname,
                               offset);
         return false;
     }
 
     if ((hdr->xlp_info & ~XLP_ALL_FLAGS) != 0)
     {
         char        fname[MAXFNAMELEN];
 
         XLogFileName(fname, state->readPageTLI, segno);
 
         report_invalid_record(state,
                               "invalid info bits %04X in log segment %s, offset %u",
                               hdr->xlp_info,
                               fname,
                               offset);
         return false;
     }
 
     if (hdr->xlp_info & XLP_LONG_HEADER)
     {
         XLogLongPageHeader longhdr = (XLogLongPageHeader) hdr;
 
         if (state->system_identifier &&
             longhdr->xlp_sysid != state->system_identifier)
         {
             char        fhdrident_str[32];
             char        sysident_str[32];
 
             /*
              * Format sysids separately to keep platform-dependent format code
              * out of the translatable message string.
              */
             snprintf(fhdrident_str, sizeof(fhdrident_str), UINT64_FORMAT,
                      longhdr->xlp_sysid);
             snprintf(sysident_str, sizeof(sysident_str), UINT64_FORMAT,
                      state->system_identifier);
             report_invalid_record(state,
                                   "WAL file is from different database system: WAL file database system identifier is %s, pg_control database system identifier is %s",
                                   fhdrident_str, sysident_str);
             return false;
         }
         else if (longhdr->xlp_seg_size != XLogSegSize)
         {
             report_invalid_record(state,
                                   "WAL file is from different database system: incorrect XLOG_SEG_SIZE in page header");
             return false;
         }
         else if (longhdr->xlp_xlog_blcksz != XLOG_BLCKSZ)
         {
             report_invalid_record(state,
                                   "WAL file is from different database system: incorrect XLOG_BLCKSZ in page header");
             return false;
         }
     }
     else if (offset == 0)
     {
         char        fname[MAXFNAMELEN];
 
         XLogFileName(fname, state->readPageTLI, segno);
 
         /* hmm, first page of file doesn't have a long header? */
         report_invalid_record(state,
                               "invalid info bits %04X in log segment %s, offset %u",
                               hdr->xlp_info,
                               fname,
                               offset);
         return false;
     }
 
     if (hdr->xlp_pageaddr != recaddr)
     {
         char        fname[MAXFNAMELEN];
 
         XLogFileName(fname, state->readPageTLI, segno);
 
         report_invalid_record(state,
                               "unexpected pageaddr %X/%X in log segment %s, offset %u",
                               (uint32) (hdr->xlp_pageaddr >> 32), (uint32) hdr->xlp_pageaddr,
                               fname,
                               offset);
         return false;
     }
 
     /*
      * Since child timelines are always assigned a TLI greater than their
      * immediate parent's TLI, we should never see TLI go backwards across
      * successive pages of a consistent WAL sequence.
      *
      * Sometimes we re-read a segment that's already been (partially) read. So
      * we only verify TLIs for pages that are later than the last remembered
      * LSN.
      */
     if (recptr > state->latestPagePtr)
     {
         if (hdr->xlp_tli < state->latestPageTLI)
         {
             char        fname[MAXFNAMELEN];
 
             XLogFileName(fname, state->readPageTLI, segno);
 
             report_invalid_record(state,
                                   "out-of-sequence timeline ID %u (after %u) in log segment %s, offset %u",
                                   hdr->xlp_tli,
                                   state->latestPageTLI,
                                   fname,
                                   offset);
             return false;
         }
     }
     state->latestPagePtr = recptr;
     state->latestPageTLI = hdr->xlp_tli;
 
     return true;
 }

static bool ValidXLogRecord	(	XLogReaderState *	state,
		XLogRecord *	record,
		XLogRecPtr	recptr
	)

static

Definition at line 687 of file xlogreader.c.

References COMP_CRC32C, EQ_CRC32C, FIN_CRC32C, INIT_CRC32C, offsetof, report_invalid_record(), SizeOfXLogRecord, XLogRecord::xl_crc, and XLogRecord::xl_tot_len.

Referenced by XLogReadRecord().

 {
     pg_crc32c   crc;
 
     /* Calculate the CRC */
     INIT_CRC32C(crc);
     COMP_CRC32C(crc, ((char *) record) + SizeOfXLogRecord, record->xl_tot_len - SizeOfXLogRecord);
     /* include the record header last */
     COMP_CRC32C(crc, (char *) record, offsetof(XLogRecord, xl_crc));
     FIN_CRC32C(crc);
 
     if (!EQ_CRC32C(record->xl_crc, crc))
     {
         report_invalid_record(state,
                               "incorrect resource manager data checksum in record at %X/%X",
                               (uint32) (recptr >> 32), (uint32) recptr);
         return false;
     }
 
     return true;
 }

static bool ValidXLogRecordHeader	(	XLogReaderState *	state,
		XLogRecPtr	RecPtr,
		XLogRecPtr	PrevRecPtr,
		XLogRecord *	record,
		bool	randAccess
	)

static

Definition at line 618 of file xlogreader.c.

References report_invalid_record(), RM_MAX_ID, SizeOfXLogRecord, XLogRecord::xl_prev, XLogRecord::xl_rmid, and XLogRecord::xl_tot_len.

Referenced by XLogReadRecord().

 {
     if (record->xl_tot_len < SizeOfXLogRecord)
     {
         report_invalid_record(state,
                               "invalid record length at %X/%X: wanted %u, got %u",
                               (uint32) (RecPtr >> 32), (uint32) RecPtr,
                               (uint32) SizeOfXLogRecord, record->xl_tot_len);
         return false;
     }
     if (record->xl_rmid > RM_MAX_ID)
     {
         report_invalid_record(state,
                               "invalid resource manager ID %u at %X/%X",
                               record->xl_rmid, (uint32) (RecPtr >> 32),
                               (uint32) RecPtr);
         return false;
     }
     if (randAccess)
     {
         /*
          * We can't exactly verify the prev-link, but surely it should be less
          * than the record's own address.
          */
         if (!(record->xl_prev < RecPtr))
         {
             report_invalid_record(state,
                                   "record with incorrect prev-link %X/%X at %X/%X",
                                   (uint32) (record->xl_prev >> 32),
                                   (uint32) record->xl_prev,
                                   (uint32) (RecPtr >> 32), (uint32) RecPtr);
             return false;
         }
     }
     else
     {
         /*
          * Record's prev-link should exactly match our previous location. This
          * check guards against torn WAL pages where a stale but valid-looking
          * WAL record starts on a sector boundary.
          */
         if (record->xl_prev != PrevRecPtr)
         {
             report_invalid_record(state,
                                   "record with incorrect prev-link %X/%X at %X/%X",
                                   (uint32) (record->xl_prev >> 32),
                                   (uint32) record->xl_prev,
                                   (uint32) (RecPtr >> 32), (uint32) RecPtr);
             return false;
         }
     }
 
     return true;
 }

XLogReaderState* XLogReaderAllocate	(	XLogPageReadCB	pagereadfunc,
		void *	private_data
	)

Definition at line 67 of file xlogreader.c.

References allocate_recordbuf(), XLogReaderState::errormsg_buf, XLogReaderState::max_block_id, MAX_ERRORMSG_LEN, MCXT_ALLOC_NO_OOM, MCXT_ALLOC_ZERO, NULL, palloc_extended(), pfree(), XLogReaderState::private_data, XLogReaderState::read_page, and XLogReaderState::readBuf.

Referenced by extractPageMap(), findLastCheckpoint(), main(), readOneRecord(), StartupDecodingContext(), StartupXLOG(), XLogInsertRecord(), and XlogReadTwoPhaseData().

 {
     XLogReaderState *state;
 
     state = (XLogReaderState *)
         palloc_extended(sizeof(XLogReaderState),
                         MCXT_ALLOC_NO_OOM | MCXT_ALLOC_ZERO);
     if (!state)
         return NULL;
 
     state->max_block_id = -1;
 
     /*
      * Permanently allocate readBuf.  We do it this way, rather than just
      * making a static array, for two reasons: (1) no need to waste the
      * storage in most instantiations of the backend; (2) a static char array
      * isn't guaranteed to have any particular alignment, whereas
      * palloc_extended() will provide MAXALIGN'd storage.
      */
     state->readBuf = (char *) palloc_extended(XLOG_BLCKSZ,
                                               MCXT_ALLOC_NO_OOM);
     if (!state->readBuf)
     {
         pfree(state);
         return NULL;
     }
 
     state->read_page = pagereadfunc;
     /* system_identifier initialized to zeroes above */
     state->private_data = private_data;
     /* ReadRecPtr and EndRecPtr initialized to zeroes above */
     /* readSegNo, readOff, readLen, readPageTLI initialized to zeroes above */
     state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1,
                                           MCXT_ALLOC_NO_OOM);
     if (!state->errormsg_buf)
     {
         pfree(state->readBuf);
         pfree(state);
         return NULL;
     }
     state->errormsg_buf[0] = '\0';
 
     /*
      * Allocate an initial readRecordBuf of minimal size, which can later be
      * enlarged if necessary.
      */
     if (!allocate_recordbuf(state, 0))
     {
         pfree(state->errormsg_buf);
         pfree(state->readBuf);
         pfree(state);
         return NULL;
     }
 
     return state;
 }

void XLogReaderFree ( XLogReaderState * state )

Definition at line 125 of file xlogreader.c.

References XLogReaderState::blocks, DecodedBkpBlock::data, XLogReaderState::errormsg_buf, XLogReaderState::main_data, pfree(), XLogReaderState::readBuf, XLogReaderState::readRecordBuf, and XLR_MAX_BLOCK_ID.

Referenced by extractPageMap(), findLastCheckpoint(), FreeDecodingContext(), main(), readOneRecord(), StartupXLOG(), and XlogReadTwoPhaseData().

 {
     int         block_id;
 
     for (block_id = 0; block_id <= XLR_MAX_BLOCK_ID; block_id++)
     {
         if (state->blocks[block_id].data)
             pfree(state->blocks[block_id].data);
     }
     if (state->main_data)
         pfree(state->main_data);
 
     pfree(state->errormsg_buf);
     if (state->readRecordBuf)
         pfree(state->readRecordBuf);
     pfree(state->readBuf);
     pfree(state);
 }

void XLogReaderInvalReadState ( XLogReaderState * state )

Definition at line 604 of file xlogreader.c.

References XLogReaderState::readLen, XLogReaderState::readOff, and XLogReaderState::readSegNo.

Referenced by ReadPageInternal(), and XLogReadRecord().

 {
     state->readSegNo = 0;
     state->readOff = 0;
     state->readLen = 0;
 }

XLogRecord* XLogReadRecord	(	XLogReaderState *	state,
		XLogRecPtr	RecPtr,
		char **	errormsg
	)

Definition at line 193 of file xlogreader.c.

References allocate_recordbuf(), Assert, buffer, XLogReaderState::currRecPtr, DecodeXLogRecord(), XLogReaderState::EndRecPtr, XLogReaderState::errormsg_buf, InvalidXLogRecPtr, MAXALIGN, Min, NULL, XLogReaderState::readBuf, readOff, ReadPageInternal(), XLogReaderState::readRecordBuf, XLogReaderState::readRecordBufSize, XLogReaderState::ReadRecPtr, report_invalid_record(), ResetDecoder(), SizeOfXLogRecord, SizeOfXLogShortPHD, ValidXLogRecord(), ValidXLogRecordHeader(), XLogRecord::xl_info, XLogRecord::xl_rmid, XLogRecord::xl_tot_len, XLOG_SWITCH, XLogPageHeaderSize, XLogReaderInvalReadState(), XLogSegSize, XLP_FIRST_IS_CONTRECORD, XLogPageHeaderData::xlp_info, XLogPageHeaderData::xlp_rem_len, XLR_INFO_MASK, and XRecOffIsValid.

Referenced by DecodingContextFindStartpoint(), extractPageMap(), findLastCheckpoint(), main(), pg_logical_slot_get_changes_guts(), readOneRecord(), ReadRecord(), XlogReadTwoPhaseData(), and XLogSendLogical().

 {
     XLogRecord *record;
     XLogRecPtr  targetPagePtr;
     bool        randAccess;
     uint32      len,
                 total_len;
     uint32      targetRecOff;
     uint32      pageHeaderSize;
     bool        gotheader;
     int         readOff;
 
     /*
      * randAccess indicates whether to verify the previous-record pointer of
      * the record we're reading.  We only do this if we're reading
      * sequentially, which is what we initially assume.
      */
     randAccess = false;
 
     /* reset error state */
     *errormsg = NULL;
     state->errormsg_buf[0] = '\0';
 
     ResetDecoder(state);
 
     if (RecPtr == InvalidXLogRecPtr)
     {
         /* No explicit start point; read the record after the one we just read */
         RecPtr = state->EndRecPtr;
 
         if (state->ReadRecPtr == InvalidXLogRecPtr)
             randAccess = true;
 
         /*
          * RecPtr is pointing to end+1 of the previous WAL record.  If we're
          * at a page boundary, no more records can fit on the current page. We
          * must skip over the page header, but we can't do that until we've
          * read in the page, since the header size is variable.
          */
     }
     else
     {
         /*
          * Caller supplied a position to start at.
          *
          * In this case, the passed-in record pointer should already be
          * pointing to a valid record starting position.
          */
         Assert(XRecOffIsValid(RecPtr));
         randAccess = true;
     }
 
     state->currRecPtr = RecPtr;
 
     targetPagePtr = RecPtr - (RecPtr % XLOG_BLCKSZ);
     targetRecOff = RecPtr % XLOG_BLCKSZ;
 
     /*
      * Read the page containing the record into state->readBuf. Request enough
      * byte to cover the whole record header, or at least the part of it that
      * fits on the same page.
      */
     readOff = ReadPageInternal(state,
                                targetPagePtr,
                                Min(targetRecOff + SizeOfXLogRecord, XLOG_BLCKSZ));
     if (readOff < 0)
         goto err;
 
     /*
      * ReadPageInternal always returns at least the page header, so we can
      * examine it now.
      */
     pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf);
     if (targetRecOff == 0)
     {
         /*
          * At page start, so skip over page header.
          */
         RecPtr += pageHeaderSize;
         targetRecOff = pageHeaderSize;
     }
     else if (targetRecOff < pageHeaderSize)
     {
         report_invalid_record(state, "invalid record offset at %X/%X",
                               (uint32) (RecPtr >> 32), (uint32) RecPtr);
         goto err;
     }
 
     if ((((XLogPageHeader) state->readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) &&
         targetRecOff == pageHeaderSize)
     {
         report_invalid_record(state, "contrecord is requested by %X/%X",
                               (uint32) (RecPtr >> 32), (uint32) RecPtr);
         goto err;
     }
 
     /* ReadPageInternal has verified the page header */
     Assert(pageHeaderSize <= readOff);
 
     /*
      * Read the record length.
      *
      * NB: Even though we use an XLogRecord pointer here, the whole record
      * header might not fit on this page. xl_tot_len is the first field of the
      * struct, so it must be on this page (the records are MAXALIGNed), but we
      * cannot access any other fields until we've verified that we got the
      * whole header.
      */
     record = (XLogRecord *) (state->readBuf + RecPtr % XLOG_BLCKSZ);
     total_len = record->xl_tot_len;
 
     /*
      * If the whole record header is on this page, validate it immediately.
      * Otherwise do just a basic sanity check on xl_tot_len, and validate the
      * rest of the header after reading it from the next page.  The xl_tot_len
      * check is necessary here to ensure that we enter the "Need to reassemble
      * record" code path below; otherwise we might fail to apply
      * ValidXLogRecordHeader at all.
      */
     if (targetRecOff <= XLOG_BLCKSZ - SizeOfXLogRecord)
     {
         if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr, record,
                                    randAccess))
             goto err;
         gotheader = true;
     }
     else
     {
         /* XXX: more validation should be done here */
         if (total_len < SizeOfXLogRecord)
         {
             report_invalid_record(state,
                                   "invalid record length at %X/%X: wanted %u, got %u",
                                   (uint32) (RecPtr >> 32), (uint32) RecPtr,
                                   (uint32) SizeOfXLogRecord, total_len);
             goto err;
         }
         gotheader = false;
     }
 
     /*
      * Enlarge readRecordBuf as needed.
      */
     if (total_len > state->readRecordBufSize &&
         !allocate_recordbuf(state, total_len))
     {
         /* We treat this as a "bogus data" condition */
         report_invalid_record(state, "record length %u at %X/%X too long",
                               total_len,
                               (uint32) (RecPtr >> 32), (uint32) RecPtr);
         goto err;
     }
 
     len = XLOG_BLCKSZ - RecPtr % XLOG_BLCKSZ;
     if (total_len > len)
     {
         /* Need to reassemble record */
         char       *contdata;
         XLogPageHeader pageHeader;
         char       *buffer;
         uint32      gotlen;
 
         /* Copy the first fragment of the record from the first page. */
         memcpy(state->readRecordBuf,
                state->readBuf + RecPtr % XLOG_BLCKSZ, len);
         buffer = state->readRecordBuf + len;
         gotlen = len;
 
         do
         {
             /* Calculate pointer to beginning of next page */
             targetPagePtr += XLOG_BLCKSZ;
 
             /* Wait for the next page to become available */
             readOff = ReadPageInternal(state, targetPagePtr,
                                        Min(total_len - gotlen + SizeOfXLogShortPHD,
                                            XLOG_BLCKSZ));
 
             if (readOff < 0)
                 goto err;
 
             Assert(SizeOfXLogShortPHD <= readOff);
 
             /* Check that the continuation on next page looks valid */
             pageHeader = (XLogPageHeader) state->readBuf;
             if (!(pageHeader->xlp_info & XLP_FIRST_IS_CONTRECORD))
             {
                 report_invalid_record(state,
                                       "there is no contrecord flag at %X/%X",
                                       (uint32) (RecPtr >> 32), (uint32) RecPtr);
                 goto err;
             }
 
             /*
              * Cross-check that xlp_rem_len agrees with how much of the record
              * we expect there to be left.
              */
             if (pageHeader->xlp_rem_len == 0 ||
                 total_len != (pageHeader->xlp_rem_len + gotlen))
             {
                 report_invalid_record(state,
                                       "invalid contrecord length %u at %X/%X",
                                       pageHeader->xlp_rem_len,
                                       (uint32) (RecPtr >> 32), (uint32) RecPtr);
                 goto err;
             }
 
             /* Append the continuation from this page to the buffer */
             pageHeaderSize = XLogPageHeaderSize(pageHeader);
 
             if (readOff < pageHeaderSize)
                 readOff = ReadPageInternal(state, targetPagePtr,
                                            pageHeaderSize);
 
             Assert(pageHeaderSize <= readOff);
 
             contdata = (char *) state->readBuf + pageHeaderSize;
             len = XLOG_BLCKSZ - pageHeaderSize;
             if (pageHeader->xlp_rem_len < len)
                 len = pageHeader->xlp_rem_len;
 
             if (readOff < pageHeaderSize + len)
                 readOff = ReadPageInternal(state, targetPagePtr,
                                            pageHeaderSize + len);
 
             memcpy(buffer, (char *) contdata, len);
             buffer += len;
             gotlen += len;
 
             /* If we just reassembled the record header, validate it. */
             if (!gotheader)
             {
                 record = (XLogRecord *) state->readRecordBuf;
                 if (!ValidXLogRecordHeader(state, RecPtr, state->ReadRecPtr,
                                            record, randAccess))
                     goto err;
                 gotheader = true;
             }
         } while (gotlen < total_len);
 
         Assert(gotheader);
 
         record = (XLogRecord *) state->readRecordBuf;
         if (!ValidXLogRecord(state, record, RecPtr))
             goto err;
 
         pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) state->readBuf);
         state->ReadRecPtr = RecPtr;
         state->EndRecPtr = targetPagePtr + pageHeaderSize
             + MAXALIGN(pageHeader->xlp_rem_len);
     }
     else
     {
         /* Wait for the record data to become available */
         readOff = ReadPageInternal(state, targetPagePtr,
                                    Min(targetRecOff + total_len, XLOG_BLCKSZ));
         if (readOff < 0)
             goto err;
 
         /* Record does not cross a page boundary */
         if (!ValidXLogRecord(state, record, RecPtr))
             goto err;
 
         state->EndRecPtr = RecPtr + MAXALIGN(total_len);
 
         state->ReadRecPtr = RecPtr;
         memcpy(state->readRecordBuf, record, total_len);
     }
 
     /*
      * Special processing if it's an XLOG SWITCH record
      */
     if (record->xl_rmid == RM_XLOG_ID &&
         (record->xl_info & ~XLR_INFO_MASK) == XLOG_SWITCH)
     {
         /* Pretend it extends to end of segment */
         state->EndRecPtr += XLogSegSize - 1;
         state->EndRecPtr -= state->EndRecPtr % XLogSegSize;
     }
 
     if (DecodeXLogRecord(state, record, errormsg))
         return record;
     else
         return NULL;
 
 err:
 
     /*
      * Invalidate the read state. We might read from a different source after
      * failure.
      */
     XLogReaderInvalReadState(state);
 
     if (state->errormsg_buf[0] != '\0')
         *errormsg = state->errormsg_buf;
 
     return NULL;
 }

char* XLogRecGetBlockData	(	XLogReaderState *	record,
		uint8	block_id,
		Size *	len
	)

Definition at line 1331 of file xlogreader.c.

References XLogReaderState::blocks, DecodedBkpBlock::data, DecodedBkpBlock::data_len, DecodedBkpBlock::has_data, DecodedBkpBlock::in_use, and NULL.

Referenced by _bt_restore_meta(), brin_xlog_insert_update(), brin_xlog_samepage_update(), btree_xlog_insert(), btree_xlog_newroot(), btree_xlog_split(), btree_xlog_vacuum(), DecodeInsert(), DecodeMultiInsert(), DecodeUpdate(), generic_redo(), gin_desc(), ginRedoInsert(), ginRedoInsertListPage(), ginRedoUpdateMetapage(), ginRedoVacuumDataLeafPage(), gistRedoPageSplitRecord(), gistRedoPageUpdateRecord(), hash_xlog_add_ovfl_page(), hash_xlog_delete(), hash_xlog_insert(), hash_xlog_move_page_contents(), hash_xlog_split_allocate_page(), hash_xlog_squeeze_page(), heap_xlog_clean(), heap_xlog_freeze_page(), heap_xlog_inplace(), heap_xlog_insert(), heap_xlog_multi_insert(), and heap_xlog_update().

 {
     DecodedBkpBlock *bkpb;
 
     if (!record->blocks[block_id].in_use)
         return NULL;
 
     bkpb = &record->blocks[block_id];
 
     if (!bkpb->has_data)
     {
         if (len)
             *len = 0;
         return NULL;
     }
     else
     {
         if (len)
             *len = bkpb->data_len;
         return bkpb->data;
     }
 }

bool XLogRecGetBlockTag	(	XLogReaderState *	record,
		uint8	block_id,
		RelFileNode *	rnode,
		ForkNumber *	forknum,
		BlockNumber *	blknum
	)

Definition at line 1307 of file xlogreader.c.

References DecodedBkpBlock::blkno, XLogReaderState::blocks, DecodedBkpBlock::forknum, DecodedBkpBlock::in_use, and DecodedBkpBlock::rnode.

Referenced by brin_xlog_revmap_extend(), btree_xlog_delete(), btree_xlog_delete_get_latestRemovedXid(), btree_xlog_split(), btree_xlog_vacuum(), checkXLogConsistency(), DecodeDelete(), DecodeInsert(), DecodeMultiInsert(), DecodeSpecConfirm(), DecodeUpdate(), extractPageInfo(), gistRedoPageSplitRecord(), hash_xlog_add_ovfl_page(), hash_xlog_vacuum_get_latestRemovedXid(), hash_xlog_vacuum_one_page(), heap_xlog_clean(), heap_xlog_delete(), heap_xlog_freeze_page(), heap_xlog_insert(), heap_xlog_lock(), heap_xlog_lock_updated(), heap_xlog_multi_insert(), heap_xlog_update(), heap_xlog_visible(), spgRedoAddLeaf(), spgRedoAddNode(), spgRedoMoveLeafs(), spgRedoPickSplit(), spgRedoVacuumRedirect(), XLogDumpDisplayRecord(), and XLogReadBufferForRedoExtended().

 {
     DecodedBkpBlock *bkpb;
 
     if (!record->blocks[block_id].in_use)
         return false;
 
     bkpb = &record->blocks[block_id];
     if (rnode)
         *rnode = bkpb->rnode;
     if (forknum)
         *forknum = bkpb->forknum;
     if (blknum)
         *blknum = bkpb->blkno;
     return true;
 }

Macros

Functions

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Function Documentation