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 <[email protected]>
Author: Tom Lane <[email protected]>
Author: Álvaro Herrera <[email protected]>
Discussion: https://postgr.es/m/20200611153753[email protected]

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;
 }