Ensure write failure reports no-disk-space

A few places calling fwrite and gzwrite were not setting errno to ENOSPC
when reporting errors, as is customary; this led to some failures being
reported as
"could not write file: Success"
which makes us look silly.  Make a few of these places in pg_dump and
pg_basebackup use our customary pattern.

Backpatch-to: 9.5
Author: Justin Pryzby <pryzby@telsasoft.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/20200611153753.GU14879@telsasoft.com

diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c
index dfd45aecc5642d96aeeb01367ed2e3a4a0aaae24..d472f4d1c237373e7d12fa658e6bd3f723064994 100644 (file)
--- a/src/bin/pg_basebackup/pg_basebackup.c
+++ b/src/bin/pg_basebackup/pg_basebackup.c
@@ -892,8 +892,12 @@ writeTarData(
 #ifdef HAVE_LIBZ
        if (ztarfile != NULL)
        {
+               errno = 0;
                if (gzwrite(ztarfile, buf, r) != r)
                {
+                       /* if write didn't set errno, assume problem is no disk space */
+                       if (errno == 0)
+                               errno = ENOSPC;
                        pg_log_error("could not write to compressed file \"%s\": %s",
                                                 current_file, get_gz_error(ztarfile));
                        exit(1);
@@ -902,8 +906,12 @@ writeTarData(
        else
 #endif
        {
+               errno = 0;
                if (fwrite(buf, r, 1, tarfile) != 1)
                {
+                       /* if write didn't set errno, assume problem is no disk space */
+                       if (errno == 0)
+                               errno = ENOSPC;
                        pg_log_error("could not write to file \"%s\": %m", current_file);
                        exit(1);
                }
@@ -1596,8 +1604,12 @@ ReceiveAndUnpackTarFile(PGconn *conn, PGresult *res, int rownum)
                                continue;
                        }
 
+                       errno = 0;
                        if (fwrite(copybuf, r, 1, file) != 1)
                        {
+                               /* if write didn't set errno, assume problem is no disk space */
+                               if (errno == 0)
+                                       errno = ENOSPC;
                                pg_log_error("could not write to file \"%s\": %m", filename);
                                exit(1);
                        }

diff --git a/src/bin/pg_dump/pg_backup_directory.c b/src/bin/pg_dump/pg_backup_directory.c
index dbe8b3836df8ebf45df2e8ddaf6acd94a95a1342..ffea0f7fd73e403dd6ebc5d899017a310cc7440e 100644 (file)
--- a/src/bin/pg_dump/pg_backup_directory.c
+++ b/src/bin/pg_dump/pg_backup_directory.c
@@ -346,10 +346,15 @@ _WriteData(ArchiveHandle *AH, const void *data, size_t dLen)
 {
        lclContext *ctx = (lclContext *) AH->formatData;
 
+       errno = 0;
        if (dLen > 0 && cfwrite(data, dLen, ctx->dataFH) != dLen)
+       {
+               /* if write didn't set errno, assume problem is no disk space */
+               if (errno == 0)
+                       errno = ENOSPC;
                fatal("could not write to output file: %s",
                          get_cfp_error(ctx->dataFH));
-
+       }
 
        return;
 }
@@ -484,9 +489,15 @@ _WriteByte(ArchiveHandle *AH, const int i)
        unsigned char c = (unsigned char) i;
        lclContext *ctx = (lclContext *) AH->formatData;
 
+       errno = 0;
        if (cfwrite(&c, 1, ctx->dataFH) != 1)
+       {
+               /* if write didn't set errno, assume problem is no disk space */
+               if (errno == 0)
+                       errno = ENOSPC;
                fatal("could not write to output file: %s",
                          get_cfp_error(ctx->dataFH));
+       }
 
        return 1;
 }
@@ -514,9 +525,15 @@ _WriteBuf(ArchiveHandle *AH, const void *buf, size_t len)
 {
        lclContext *ctx = (lclContext *) AH->formatData;
 
+       errno = 0;
        if (cfwrite(buf, len, ctx->dataFH) != len)
+       {
+               /* if write didn't set errno, assume problem is no disk space */
+               if (errno == 0)
+                       errno = ENOSPC;
                fatal("could not write to output file: %s",
                          get_cfp_error(ctx->dataFH));
+       }
 
        return;
 }