Reset properly errno before calling write()

michaelpq · michaelpq · commit f5b4bb88120f · 2018-08-05T05:32:27.000+09:00
6cb3372 enforces errno to ENOSPC when less bytes than what is expected have been written when it is unset, though it forgot to properly reset errno before doing a system call to write(), causing errno to potentially come from a previous system call. Reported-by: Tom Lane Author: Michael Paquier Reviewed-by: Tom Lane Discussion: https://postgr.es/m/31797.1533326676@sss.pgh.pa.us
diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
@@ -1162,6 +1162,7 @@ heap_xlog_logical_rewrite(XLogReaderState *r)
 	len = xlrec->num_mappings * sizeof(LogicalRewriteMappingData);
 
 	/* write out tail end of mapping file (again) */
+	errno = 0;
 	if (write(fd, data, len) != len)
 	{
 		/* if write didn't set errno, assume problem is no disk space */
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
@@ -1553,6 +1553,7 @@ RecreateTwoPhaseFile(TransactionId xid, void *content, int len)
 						path)));
 
 	/* Write content and CRC */
+	errno = 0;
 	if (write(fd, content, len) != len)
 	{
 		int			save_errno = errno;
diff --git a/src/backend/replication/logical/origin.c b/src/backend/replication/logical/origin.c
@@ -547,6 +547,7 @@ CheckPointReplicationOrigin(void)
 						tmppath)));
 
 	/* write magic */
+	errno = 0;
 	if ((write(tmpfd, &magic, sizeof(magic))) != sizeof(magic))
 	{
 		int			save_errno = errno;
@@ -590,6 +591,7 @@ CheckPointReplicationOrigin(void)
 		/* make sure we only write out a commit that's persistent */
 		XLogFlush(local_lsn);
 
+		errno = 0;
 		if ((write(tmpfd, &disk_state, sizeof(disk_state))) !=
 			sizeof(disk_state))
 		{
@@ -612,6 +614,7 @@ CheckPointReplicationOrigin(void)
 
 	/* write out the CRC */
 	FIN_CRC32C(crc);
+	errno = 0;
 	if ((write(tmpfd, &crc, sizeof(crc))) != sizeof(crc))
 	{
 		int			save_errno = errno;
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
@@ -2479,6 +2479,7 @@ ReorderBufferSerializeChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 
 	ondisk->size = sz;
 
+	errno = 0;
 	if (write(fd, rb->outbuf, ondisk->size) != ondisk->size)
 	{
 		int			save_errno = errno;
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
@@ -1588,6 +1588,7 @@ SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn)
 		ereport(ERROR,
 				(errmsg("could not open file \"%s\": %m", path)));
 
+	errno = 0;
 	if ((write(fd, ondisk, needed_length)) != needed_length)
 	{
 		int			save_errno = errno;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
@@ -1080,6 +1080,7 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel)
 				SnapBuildOnDiskChecksummedSize);
 	FIN_CRC32C(cp.checksum);
 
+	errno = 0;
 	if ((write(fd, &cp, sizeof(cp))) != sizeof(cp))
 	{
 		int			save_errno = errno;
diff --git a/src/bin/pg_basebackup/receivelog.c b/src/bin/pg_basebackup/receivelog.c
@@ -147,6 +147,7 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
 	zerobuf = pg_malloc0(XLOG_BLCKSZ);
 	for (bytes = 0; bytes < XLogSegSize; bytes += XLOG_BLCKSZ)
 	{
+		errno = 0;
 		if (write(f, zerobuf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
 		{
 			/* if write didn't set errno, assume problem is no disk space */
@@ -1189,6 +1190,7 @@ ProcessXLogDataMsg(PGconn *conn, StreamCtl *stream, char *copybuf, int len,
 			}
 		}
 
+		errno = 0;
 		if (write(walfile,
 				  copybuf + hdr_len + bytes_written,
 				  bytes_to_write) != bytes_to_write)

Original file line number	Diff line number	Diff line change
`@@ -1162,6 +1162,7 @@ heap_xlog_logical_rewrite(XLogReaderState *r)`
`1162`	`1162`	`len = xlrec->num_mappings * sizeof(LogicalRewriteMappingData);`
`1163`	`1163`
`1164`	`1164`	`/* write out tail end of mapping file (again) */`
	`1165`	`+ errno = 0;`
`1165`	`1166`	`if (write(fd, data, len) != len)`
`1166`	`1167`	`{`
`1167`	`1168`	`/* if write didn't set errno, assume problem is no disk space */`
Original file line number	Diff line number	Diff line change
`@@ -1553,6 +1553,7 @@ RecreateTwoPhaseFile(TransactionId xid, void *content, int len)`
`1553`	`1553`	`path)));`
`1554`	`1554`
`1555`	`1555`	`/* Write content and CRC */`
	`1556`	`+ errno = 0;`
`1556`	`1557`	`if (write(fd, content, len) != len)`
`1557`	`1558`	`{`
`1558`	`1559`	`int save_errno = errno;`
Original file line number	Diff line number	Diff line change
`@@ -547,6 +547,7 @@ CheckPointReplicationOrigin(void)`
`547`	`547`	`tmppath)));`
`548`	`548`
`549`	`549`	`/* write magic */`
	`550`	`+ errno = 0;`
`550`	`551`	`if ((write(tmpfd, &magic, sizeof(magic))) != sizeof(magic))`
`551`	`552`	`{`
`552`	`553`	`int save_errno = errno;`
`@@ -590,6 +591,7 @@ CheckPointReplicationOrigin(void)`
`590`	`591`	`/* make sure we only write out a commit that's persistent */`
`591`	`592`	`XLogFlush(local_lsn);`
`592`	`593`
	`594`	`+ errno = 0;`
`593`	`595`	`if ((write(tmpfd, &disk_state, sizeof(disk_state))) !=`
`594`	`596`	`sizeof(disk_state))`
`595`	`597`	`{`
`@@ -612,6 +614,7 @@ CheckPointReplicationOrigin(void)`
`612`	`614`
`613`	`615`	`/* write out the CRC */`
`614`	`616`	`FIN_CRC32C(crc);`
	`617`	`+ errno = 0;`
`615`	`618`	`if ((write(tmpfd, &crc, sizeof(crc))) != sizeof(crc))`
`616`	`619`	`{`
`617`	`620`	`int save_errno = errno;`
Original file line number	Diff line number	Diff line change
`@@ -2479,6 +2479,7 @@ ReorderBufferSerializeChange(ReorderBuffer rb, ReorderBufferTXN txn,`
`2479`	`2479`
`2480`	`2480`	`ondisk->size = sz;`
`2481`	`2481`
	`2482`	`+ errno = 0;`
`2482`	`2483`	`if (write(fd, rb->outbuf, ondisk->size) != ondisk->size)`
`2483`	`2484`	`{`
`2484`	`2485`	`int save_errno = errno;`
Original file line number	Diff line number	Diff line change
`@@ -1588,6 +1588,7 @@ SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn)`
`1588`	`1588`	`ereport(ERROR,`
`1589`	`1589`	`(errmsg("could not open file \"%s\": %m", path)));`
`1590`	`1590`
	`1591`	`+ errno = 0;`
`1591`	`1592`	`if ((write(fd, ondisk, needed_length)) != needed_length)`
`1592`	`1593`	`{`
`1593`	`1594`	`int save_errno = errno;`
Original file line number	Diff line number	Diff line change
`@@ -1080,6 +1080,7 @@ SaveSlotToPath(ReplicationSlot slot, const char dir, int elevel)`
`1080`	`1080`	`SnapBuildOnDiskChecksummedSize);`
`1081`	`1081`	`FIN_CRC32C(cp.checksum);`
`1082`	`1082`
	`1083`	`+ errno = 0;`
`1083`	`1084`	`if ((write(fd, &cp, sizeof(cp))) != sizeof(cp))`
`1084`	`1085`	`{`
`1085`	`1086`	`int save_errno = errno;`
Original file line number	Diff line number	Diff line change
`@@ -147,6 +147,7 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)`
`147`	`147`	`zerobuf = pg_malloc0(XLOG_BLCKSZ);`
`148`	`148`	`for (bytes = 0; bytes < XLogSegSize; bytes += XLOG_BLCKSZ)`
`149`	`149`	`{`
	`150`	`+ errno = 0;`
`150`	`151`	`if (write(f, zerobuf, XLOG_BLCKSZ) != XLOG_BLCKSZ)`
`151`	`152`	`{`
`152`	`153`	`/* if write didn't set errno, assume problem is no disk space */`
`@@ -1189,6 +1190,7 @@ ProcessXLogDataMsg(PGconn conn, StreamCtl stream, char *copybuf, int len,`
`1189`	`1190`	`}`
`1190`	`1191`	`}`
`1191`	`1192`
	`1193`	`+ errno = 0;`
`1192`	`1194`	`if (write(walfile,`
`1193`	`1195`	`copybuf + hdr_len + bytes_written,`
`1194`	`1196`	`bytes_to_write) != bytes_to_write)`