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 ed7ba181c79672d849a06214b5ed1116649b37be..85f92973c95cf6f05fd7139e6d2332aabd4ceebb 100644 (file)
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1166,6 +1166,7 @@ heap_xlog_logical_rewrite(XLogReaderState *r)
        len = xlrec->num_mappings * sizeof(LogicalRewriteMappingData);
 
        /* write out tail end of mapping file (again) */
+       errno = 0;
        pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_MAPPING_WRITE);
        if (write(fd, data, len) != len)
        {

diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 306861bb793bc215e7607206199a35d5148a5ad9..0ae0722794147c1909a45bbed8bd2d2999ae5b57 100644 (file)
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -1669,6 +1669,7 @@ RecreateTwoPhaseFile(TransactionId xid, void *content, int len)
                                 errmsg("could not recreate file \"%s\": %m", path)));
 
        /* Write content and CRC */
+       errno = 0;
        pgstat_report_wait_start(WAIT_EVENT_TWOPHASE_FILE_WRITE);
        if (write(fd, content, len) != len)
        {

diff --git a/src/backend/replication/logical/origin.c b/src/backend/replication/logical/origin.c
index 822c96d1c2f82cd8c2548d8aa35175d5312122f6..bf97dcdee4b02f22e5386aa008b825c3b1dfad73 100644 (file)
--- a/src/backend/replication/logical/origin.c
+++ b/src/backend/replication/logical/origin.c
@@ -576,6 +576,7 @@ CheckPointReplicationOrigin(void)
                                                tmppath)));
 
        /* write magic */
+       errno = 0;
        if ((write(tmpfd, &magic, sizeof(magic))) != sizeof(magic))
        {
                int                     save_errno = errno;
@@ -619,6 +620,7 @@ 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))
                {
@@ -641,6 +643,7 @@ 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 9b55b94227b09686281e347ada53cf9f78563b6d..1d43a165ad04f07d5c691d0a81f13a08c56c553c 100644 (file)
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -2421,6 +2421,7 @@ ReorderBufferSerializeChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 
        ondisk->size = sz;
 
+       errno = 0;
        pgstat_report_wait_start(WAIT_EVENT_REORDER_BUFFER_WRITE);
        if (write(fd, rb->outbuf, ondisk->size) != ondisk->size)
        {

diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 1359d9b20a3578f4d59374ee68acc8d44e216925..a6cd6c67d16d8ad24bb966fbcc16f944182eed90 100644 (file)
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1609,6 +1609,7 @@ SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn)
                ereport(ERROR,
                                (errmsg("could not open file \"%s\": %m", path)));
 
+       errno = 0;
        pgstat_report_wait_start(WAIT_EVENT_SNAPBUILD_WRITE);
        if ((write(fd, ondisk, needed_length)) != needed_length)
        {

diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 6c3639805833992e76d43c3aff50a4bf33780d88..19978d9a9edc4429dae68b9f08342d86919467d8 100644 (file)
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -1275,6 +1275,7 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel)
                                SnapBuildOnDiskChecksummedSize);
        FIN_CRC32C(cp.checksum);
 
+       errno = 0;
        pgstat_report_wait_start(WAIT_EVENT_REPLICATION_SLOT_WRITE);
        if ((write(fd, &cp, sizeof(cp))) != sizeof(cp))
        {

diff --git a/src/bin/pg_basebackup/walmethods.c b/src/bin/pg_basebackup/walmethods.c
index fbfee05a5a6b2aed88e673bc7eb486fc797e61d6..42e3f3023a0f22378c4d6a082de9b6379176bf8b 100644 (file)
--- a/src/bin/pg_basebackup/walmethods.c
+++ b/src/bin/pg_basebackup/walmethods.c
@@ -122,6 +122,7 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
                zerobuf = pg_malloc0(XLOG_BLCKSZ);
                for (bytes = 0; bytes < pad_to_size; bytes += XLOG_BLCKSZ)
                {
+                       errno = 0;
                        if (write(fd, zerobuf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
                        {
                                int                     save_errno = errno;
@@ -445,6 +446,7 @@ tar_write_compressed_data(void *buf, size_t count, bool flush)
                {
                        size_t          len = ZLIB_OUT_SIZE - tar_data->zp->avail_out;
 
+                       errno = 0;
                        if (write(tar_data->fd, tar_data->zlibOut, len) != len)
                        {
                                /*
@@ -629,6 +631,7 @@ tar_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
 
        if (!tar_data->compression)
        {
+               errno = 0;
                if (write(tar_data->fd, tar_data->currentfile->header, 512) != 512)
                {
                        save_errno = errno;
@@ -829,6 +832,7 @@ tar_close(Walfile f, WalCloseMethod method)
                return -1;
        if (!tar_data->compression)
        {
+               errno = 0;
                if (write(tar_data->fd, tf->header, 512) != 512)
                {
                        /* if write didn't set errno, assume problem is no disk space */
@@ -901,6 +905,7 @@ tar_finish(void)
        MemSet(zerobuf, 0, sizeof(zerobuf));
        if (!tar_data->compression)
        {
+               errno = 0;
                if (write(tar_data->fd, zerobuf, sizeof(zerobuf)) != sizeof(zerobuf))
                {
                        /* if write didn't set errno, assume problem is no disk space */
@@ -933,6 +938,7 @@ tar_finish(void)
                        {
                                size_t          len = ZLIB_OUT_SIZE - tar_data->zp->avail_out;
 
+                               errno = 0;
                                if (write(tar_data->fd, tar_data->zlibOut, len) != len)
                                {
                                        /*