/*
* Attempt to read an XLOG record into readRecordBuf.
*/
static bool
ReadRecord(void)
{
char *buffer;
XLogRecord *record;
XLogContRecord *contrecord;
uint32 len,
total_len;
int retries = 0;
restart:
while (logRecOff <= 0 || logRecOff > XLOG_BLCKSZ - SizeOfXLogRecord)
{
/* Need to advance to new page */
if (! readXLogPage())
return false;
logRecOff = XLogPageHeaderSize((XLogPageHeader) pageBuffer);
if ((((XLogPageHeader) pageBuffer)->xlp_info & ~XLP_LONG_HEADER) != 0)
{
printf("Unexpected page info flags %04X at offset %X\n",
((XLogPageHeader) pageBuffer)->xlp_info, logPageOff);
/* Check for a continuation record */
if (((XLogPageHeader) pageBuffer)->xlp_info & XLP_FIRST_IS_CONTRECORD)
{
printf("Skipping unexpected continuation record at offset %X\n",
logPageOff);
contrecord = (XLogContRecord *) (pageBuffer + logRecOff);
logRecOff += MAXALIGN(contrecord->xl_rem_len + SizeOfXLogContRecord);
}
}
}
curRecPtr.xlogid = logId;
curRecPtr.xrecoff = logSeg * XLogSegSize + logPageOff + logRecOff;
record = (XLogRecord *) (pageBuffer + logRecOff);
if (record->xl_len == 0)
{
/* Stop if XLOG_SWITCH was found. */
if (record->xl_rmid == RM_XLOG_ID && record->xl_info == XLOG_SWITCH)
{
dumpXLogRecord(record, false);
return false;
}
printf("ReadRecord: record with zero len at %u/%08X\n",
curRecPtr.xlogid, curRecPtr.xrecoff);
/* Attempt to recover on new page, but give up after a few... */
logRecOff = 0;
if (++retries > 4)
return false;
goto restart;
}
if (record->xl_tot_len < SizeOfXLogRecord + record->xl_len ||
record->xl_tot_len > SizeOfXLogRecord + record->xl_len +
XLR_MAX_BKP_BLOCKS * (sizeof(BkpBlock) + BLCKSZ))
{
printf(
"invalid record length(expected %lu ~ %lu, actual %d) at %X/%X\n",
(unsigned long) (SizeOfXLogRecord + record->xl_len),
(unsigned long) (SizeOfXLogRecord + record->xl_len +
XLR_MAX_BKP_BLOCKS * (sizeof(BkpBlock) + BLCKSZ)),
record->xl_tot_len,
curRecPtr.xlogid, curRecPtr.xrecoff);
printf("HINT: Make sure you're using the correct xlogdump binary built against\n"
" the same architecture and version of PostgreSQL where the WAL file\n"
" comes from.\n");
return false;
}
total_len = record->xl_tot_len;
/*
* Allocate or enlarge readRecordBuf as needed. To avoid useless
* small increases, round its size to a multiple of XLOG_BLCKSZ, and make
* sure it's at least 4*BLCKSZ to start with. (That is enough for all
* "normal" records, but very large commit or abort records might need
* more space.)
*/
if (total_len > readRecordBufSize)
{
uint32 newSize = total_len;
newSize += XLOG_BLCKSZ - (newSize % XLOG_BLCKSZ);
newSize = Max(newSize, 4 * XLOG_BLCKSZ);
if (readRecordBuf)
free(readRecordBuf);
readRecordBuf = (char *) malloc(newSize);
if (!readRecordBuf)
{
readRecordBufSize = 0;
/* We treat this as a "bogus data" condition */
fprintf(stderr, "record length %u at %X/%X too long\n",
total_len, curRecPtr.xlogid, curRecPtr.xrecoff);
return false;
}
readRecordBufSize = newSize;
}
buffer = readRecordBuf;
len = XLOG_BLCKSZ - curRecPtr.xrecoff % XLOG_BLCKSZ; /* available in block */
if (total_len > len)
{
/* Need to reassemble record */
uint32 gotlen = len;
memcpy(buffer, record, len);
record = (XLogRecord *) buffer;
buffer += len;
for (;;)
{
uint32 pageHeaderSize;
if (! readXLogPage())
{
/* XXX ought to be able to advance to new input file! */
fprintf(stderr, "Unable to read continuation page?\n");
dumpXLogRecord(record, true);
return false;
}
if (!(((XLogPageHeader) pageBuffer)->xlp_info & XLP_FIRST_IS_CONTRECORD))
{
printf("ReadRecord: there is no ContRecord flag in logfile %u seg %u off %u\n",
logId, logSeg, logPageOff);
return false;
}
pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) pageBuffer);
contrecord = (XLogContRecord *) (pageBuffer + pageHeaderSize);
if (contrecord->xl_rem_len == 0 ||
total_len != (contrecord->xl_rem_len + gotlen))
{
printf("ReadRecord: invalid cont-record len %u in logfile %u seg %u off %u\n",
contrecord->xl_rem_len, logId, logSeg, logPageOff);
return false;
}
len = XLOG_BLCKSZ - pageHeaderSize - SizeOfXLogContRecord;
if (contrecord->xl_rem_len > len)
{
memcpy(buffer, (char *)contrecord + SizeOfXLogContRecord, len);
gotlen += len;
buffer += len;
continue;
}
memcpy(buffer, (char *) contrecord + SizeOfXLogContRecord,
contrecord->xl_rem_len);
logRecOff = MAXALIGN(pageHeaderSize + SizeOfXLogContRecord + contrecord->xl_rem_len);
break;
}
if (!RecordIsValid(record, curRecPtr))
return false;
return true;
}
/* Record is contained in this page */
memcpy(buffer, record, total_len);
record = (XLogRecord *) buffer;
logRecOff += MAXALIGN(total_len);
if (!RecordIsValid(record, curRecPtr))
return false;
return true;
}
/*
* Attempt to read an XLOG record into readRecordBuf.
* Function adapted from xlogdump utility.
*/
XLogRecord *
readRecord(int *logFd, int *logRecOff, int32 *logPageOff, XLogRecPtr *curRecPtr, uint32 logId, uint32 logSeg, bool ignore_errors)
{
char *buffer;
char *readRecordBuf = NULL;
XLogRecord *record;
XLogContRecord *contrecord;
uint32 len,
total_len;
int retries = 0;
static char pageBuffer[BLCKSZ];
uint32 readRecordBufSize = 0;
restart:
while (*logRecOff <= 0 || *logRecOff > BLCKSZ - SizeOfXLogRecord)
{
/* Need to advance to new page */
if (! readXLogPage(logFd, logPageOff, pageBuffer))
return false;
*logRecOff = XLogPageHeaderSize((XLogPageHeader) pageBuffer);
if ((((XLogPageHeader) pageBuffer)->xlp_info & ~XLP_LONG_HEADER) != 0)
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Unexpected page info flags %04X at offset %X",
((XLogPageHeader) pageBuffer)->xlp_info, *logPageOff)));
/* Check for a continuation record */
if (((XLogPageHeader) pageBuffer)->xlp_info & XLP_FIRST_IS_CONTRECORD)
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Skipping unexpected continuation record at offset %X",
*logPageOff)));
contrecord = (XLogContRecord *) (pageBuffer + *logRecOff);
*logRecOff += MAXALIGN(contrecord->xl_rem_len + SizeOfXLogContRecord);
}
}
}
curRecPtr->xlogid = logId;
curRecPtr->xrecoff = logSeg * XLogSegSize + *logPageOff + *logRecOff;
record = (XLogRecord *) (pageBuffer + *logRecOff);
if (record->xl_len == 0)
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("ReadRecord: record with zero len at %u/%08X",
curRecPtr->xlogid, curRecPtr->xrecoff)));
/* Attempt to recover on new page, but give up after a few... */
*logRecOff = 0;
if (++retries > 4)
return false;
goto restart;
}
if (record->xl_tot_len < SizeOfXLogRecord + record->xl_len ||
record->xl_tot_len > SizeOfXLogRecord + record->xl_len +
XLR_MAX_BKP_BLOCKS * (sizeof(BkpBlock) + BLCKSZ))
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("invalid record length at %X/%X",
curRecPtr->xlogid, curRecPtr->xrecoff)));
return false;
}
total_len = record->xl_tot_len;
/*
* Allocate or enlarge readRecordBuf as needed. To avoid useless
* small increases, round its size to a multiple of BLCKSZ, and make
* sure it's at least 4*BLCKSZ to start with. (That is enough for all
* "normal" records, but very large commit or abort records might need
* more space.)
*/
if (total_len > readRecordBufSize)
{
uint32 newSize = total_len;
newSize += BLCKSZ - (newSize % BLCKSZ);
newSize = Max(newSize, 4 * BLCKSZ);
if (readRecordBuf)
pfree(readRecordBuf);
readRecordBuf = (char *) palloc(newSize);
if (!readRecordBuf)
{
readRecordBufSize = 0;
/* We treat this as a "bogus data" condition */
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("record length %u at %X/%X too long",
total_len, curRecPtr->xlogid, curRecPtr->xrecoff)));
return false;
}
readRecordBufSize = newSize;
}
buffer = readRecordBuf;
len = BLCKSZ - curRecPtr->xrecoff % BLCKSZ; /* available in block */
if (total_len > len)
{
/* Need to reassemble record */
uint32 gotlen = len;
memcpy(buffer, record, len);
record = (XLogRecord *) buffer;
buffer += len;
for (;;)
{
uint32 pageHeaderSize;
if (! readXLogPage(logFd, logPageOff, pageBuffer))
{
/* XXX ought to be able to advance to new input file! */
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Unable to read continuation page?")));
return false;
}
if (!(((XLogPageHeader) pageBuffer)->xlp_info & XLP_FIRST_IS_CONTRECORD))
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("ReadRecord: there is no ContRecord flag in logfile %u seg %u off %u",
logId, logSeg, *logPageOff)));
return false;
}
pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) pageBuffer);
contrecord = (XLogContRecord *) (pageBuffer + pageHeaderSize);
if (contrecord->xl_rem_len == 0 ||
total_len != (contrecord->xl_rem_len + gotlen))
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("ReadRecord: invalid cont-record len %u in logfile %u seg %u off %u",
contrecord->xl_rem_len, logId, logSeg, *logPageOff)));
return false;
}
len = BLCKSZ - pageHeaderSize - SizeOfXLogContRecord;
if (contrecord->xl_rem_len > len)
{
memcpy(buffer, (char *)contrecord + SizeOfXLogContRecord, len);
gotlen += len;
buffer += len;
continue;
}
memcpy(buffer, (char *) contrecord + SizeOfXLogContRecord,
contrecord->xl_rem_len);
*logRecOff = MAXALIGN(pageHeaderSize + SizeOfXLogContRecord + contrecord->xl_rem_len);
break;
}
if (!recordIsValid(record, curRecPtr) && !ignore_errors)
return false;
return record;
}
/* Record is contained in this page */
memcpy(buffer, record, total_len);
record = (XLogRecord *) buffer;
*logRecOff += MAXALIGN(total_len);
if (!recordIsValid(record, curRecPtr) && !ignore_errors)
return false;
return record;
}
