Patchwork [15/21] dmg: fix reading of uncompressed chunks

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Submitter Kevin Wolf
Date May 14, 2010, 5:10 p.m.
Message ID <1273857055-26715-16-git-send-email-kwolf@redhat.com>
Download mbox | patch
Permalink /patch/52644/
State New
Headers show

Comments

Kevin Wolf - May 14, 2010, 5:10 p.m.
From: Christoph Hellwig <hch@lst.de>

When dmg_read_chunk encounters an uncompressed chunk it currently
calls read without any previous adjustment of the file postion.

This seems very wrong, and the "reference" implementation in
dmg2img does a search to the same offset as done in the various
compression cases, so do the same here.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/dmg.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

Patch

diff --git a/block/dmg.c b/block/dmg.c
index d5c1a68..02a3d67 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -239,7 +239,8 @@  static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
 		return -1;
 	    break; }
 	case 1: /* copy */
-	    ret = read(s->fd, s->uncompressed_chunk, s->lengths[chunk]);
+	    ret = pread(s->fd, s->uncompressed_chunk, s->lengths[chunk],
+                        s->offsets[chunk]);
 	    if (ret != s->lengths[chunk])
 		return -1;
 	    break;