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Fix error handling of XLogReaderAllocate in case of OOM

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Similarly to previous fix 9b8d478, commit 2c03216 has switched
XLogReaderAllocate() to use a set of palloc calls instead of malloc,
causing any callers of this function to fail with an error instead of
receiving a NULL pointer in case of out-of-memory error. Fix this by
using palloc_extended with MCXT_ALLOC_NO_OOM that will safely return
NULL in case of an OOM.

Michael Paquier, slightly modified by me.
This commit is contained in:
Fujii Masao
2015-04-03 21:55:37 +09:00
parent f85155e18c
commit 6e4bf4ecd3
4 changed files with 39 additions and 9 deletions
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30
src/backend/access/transam/xlogreader.c
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@ -58,15 +58,18 @@ report_invalid_record(XLogReaderState *state, const char *fmt,...)
/*
* Allocate and initialize a new XLogReader.
*
* The returned XLogReader is palloc'd. (In FRONTEND code, that means that
* running out-of-memory causes an immediate exit(1).
* Returns NULL if the xlogreader couldn't be allocated.
*/
XLogReaderState *
XLogReaderAllocate(XLogPageReadCB pagereadfunc, void *private_data)
{
XLogReaderState *state;
state = (XLogReaderState *) palloc0(sizeof(XLogReaderState));
state = (XLogReaderState *)
palloc_extended(sizeof(XLogReaderState),
MCXT_ALLOC_NO_OOM | MCXT_ALLOC_ZERO);
if (!state)
return NULL;
state->max_block_id = -1;
@ -74,17 +77,30 @@ XLogReaderAllocate(XLogPageReadCB pagereadfunc, void *private_data)
* 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()
* will provide MAXALIGN'd storage.
* isn't guaranteed to have any particular alignment, whereas
* palloc_extended() will provide MAXALIGN'd storage.
*/
state->readBuf = (char *) palloc(XLOG_BLCKSZ);
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(MAX_ERRORMSG_LEN + 1);
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';
/*