Reset properly errno before calling write()

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
index e628c9bd89d74a33923f3a3311285a381ce15909..bbb04d90e8265d41ee55e27eb9bebcadf0f2cd31 100644 (file)
--- 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
index a23eed568318f391e46b100d3579eccc412fe00e..4429dc20083d915ad70c15c675f73b48abb02b41 100644 (file)
--- 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
index d6bae6cc89768bb740ee1cce38456b005c32fd8f..7b1385968cafb114629f48dd9f9864fd6d854c1a 100644 (file)
--- 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
index 47e669578f2a2109d0768552c19d577787a0506a..de5d2c6a1861482d2192dcec22840a933e4509f4 100644 (file)
--- 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
index 77997ec2e351b60b8b633e05b8510f069b84ff41..d8d8f03cdf9ca6cec2912541b2ee6c102f586f5e 100644 (file)
--- 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
index 59b0d846226689d203aee8613c6077a0eca40c39..62cdf2d9eacef00b830c6390fd109a87a6784756 100644 (file)
--- 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
index c9fb4198b07f1869c115b3d4db2ae7d4012c3dfc..79072a7939a6c4b91c77e7683d04364650fc8c0f 100644 (file)
--- 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)