From 84bf6ece1fffaf6d56e7de52c8dbc2d33d433618 Mon Sep 17 00:00:00 2001
From: Andrew Dunstan <andrew@dunslane.net>
Date: Sat, 25 Jul 2015 17:14:36 -0400
Subject: [PATCH] Restore use of zlib default compression in pg_dump directory
 mode.

This was broken by commit 0e7e355f27302b62af3e1add93853ccd45678443 and
friends, which ignored the fact that gzopen() will treat "-1" in the
mode argument as an invalid character, which it ignores, and a flag for
compression level 1. Now, when this value is encountered no compression
level flag is passed  to gzopen, leaving it to use the zlib default.

Also, enforce the documented allowed range for pg_dump's -Z option,
namely 0 .. 9, and remove some consequently dead code from
pg_backup_tar.c.

Problem reported by Marc Mamin.

Backpatch to 9.1, like the patch that introduced the bug.
---
 src/bin/pg_dump/compress_io.c   | 18 ++++++++++++++----
 src/bin/pg_dump/pg_backup_tar.c |  7 -------
 src/bin/pg_dump/pg_dump.c       |  5 +++++
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/src/bin/pg_dump/compress_io.c b/src/bin/pg_dump/compress_io.c
index a5f550399fd..3ba4c3969bd 100644
--- a/src/bin/pg_dump/compress_io.c
+++ b/src/bin/pg_dump/compress_io.c
@@ -560,11 +560,21 @@ cfopen(const char *path, const char *mode, int compression)
 	if (compression != 0)
 	{
 #ifdef HAVE_LIBZ
-		char		mode_compression[32];
+		if (compression != Z_DEFAULT_COMPRESSION)
+		{
+			/* user has specified a compression level, so tell zlib to use it */
+			char		mode_compression[32];
+
+			snprintf(mode_compression, sizeof(mode_compression), "%s%d",
+					 mode, compression);
+			fp->compressedfp = gzopen(path, mode_compression);
+		}
+		else
+		{
+			/* don't specify a level, just use the zlib default */
+			fp->compressedfp = gzopen(path, mode);
+		}
 
-		snprintf(mode_compression, sizeof(mode_compression), "%s%d",
-				 mode, compression);
-		fp->compressedfp = gzopen(path, mode_compression);
 		fp->uncompressedfp = NULL;
 		if (fp->compressedfp == NULL)
 		{
diff --git a/src/bin/pg_dump/pg_backup_tar.c b/src/bin/pg_dump/pg_backup_tar.c
index 2358b9d160c..0e3186caac9 100644
--- a/src/bin/pg_dump/pg_backup_tar.c
+++ b/src/bin/pg_dump/pg_backup_tar.c
@@ -209,13 +209,6 @@ InitArchiveFmt_Tar(ArchiveHandle *AH)
 
 		ctx->hasSeek = checkSeek(ctx->tarFH);
 
-		if (AH->compression < 0 || AH->compression > 9)
-			AH->compression = Z_DEFAULT_COMPRESSION;
-
-		/* Don't compress into tar files unless asked to do so */
-		if (AH->compression == Z_DEFAULT_COMPRESSION)
-			AH->compression = 0;
-
 		/*
 		 * We don't support compression because reading the files back is not
 		 * possible since gzdopen uses buffered IO which totally screws file
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index e962107c9ec..4c38ece01d8 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -514,6 +514,11 @@ main(int argc, char **argv)
 
 			case 'Z':			/* Compression Level */
 				compressLevel = atoi(optarg);
+				if (compressLevel < 0 || compressLevel > 9)
+				{
+					write_msg(NULL, "compression level must be in range 0..9\n");
+					exit_nicely(1);
+				}
 				break;
 
 			case 0: