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[Qemu-devel] [PULL for-2.0 37/51] dmg: drop broken bdrv_pread() loop
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL for-2.0 37/51] dmg: drop broken bdrv_pread() loop |
Date: |
Tue, 1 Apr 2014 19:19:15 +0200 |
It is not necessary to check errno for EINTR and the block layer does
not produce short reads. Therefore we can drop the loop that attempts
to read a compressed chunk.
The loop is buggy because it incorrectly adds the transferred bytes
twice:
do {
ret = bdrv_pread(...);
i += ret;
} while (ret >= 0 && ret + i < s->lengths[chunk]);
Luckily we can drop the loop completely and perform a single
bdrv_pread().
Signed-off-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block/dmg.c | 15 ++-------------
1 file changed, 2 insertions(+), 13 deletions(-)
diff --git a/block/dmg.c b/block/dmg.c
index f4f3e8e..1cc5426 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -298,21 +298,10 @@ static inline int dmg_read_chunk(BlockDriverState *bs,
int sector_num)
s->current_chunk = s->n_chunks;
switch (s->types[chunk]) {
case 0x80000005: { /* zlib compressed */
- int i;
-
/* we need to buffer, because only the chunk as whole can be
* inflated. */
- i = 0;
- do {
- ret = bdrv_pread(bs->file, s->offsets[chunk] + i,
- s->compressed_chunk + i,
- s->lengths[chunk] - i);
- if (ret < 0 && errno == EINTR) {
- ret = 0;
- }
- i += ret;
- } while (ret >= 0 && ret + i < s->lengths[chunk]);
-
+ ret = bdrv_pread(bs->file, s->offsets[chunk],
+ s->compressed_chunk, s->lengths[chunk]);
if (ret != s->lengths[chunk]) {
return -1;
}
--
1.9.0
- [Qemu-devel] [PULL for-2.0 27/51] qcow2: Validate active L1 table offset and size (CVE-2014-0144), (continued)
- [Qemu-devel] [PULL for-2.0 27/51] qcow2: Validate active L1 table offset and size (CVE-2014-0144), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 28/51] qcow2: Fix backing file name length check, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 29/51] qcow2: Don't rely on free_cluster_index in alloc_refcount_block() (CVE-2014-0147), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 30/51] qcow2: Avoid integer overflow in get_refcount (CVE-2014-0143), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 31/51] qcow2: Check new refcount table size on growth, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 35/51] dmg: coding style and indentation cleanup, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 36/51] dmg: prevent out-of-bounds array access on terminator, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 34/51] qcow2: Fix new L1 table size check (CVE-2014-0143), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 32/51] qcow2: Fix types in qcow2_alloc_clusters and alloc_clusters_noref, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 33/51] qcow2: Protect against some integer overflows in bdrv_check, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 37/51] dmg: drop broken bdrv_pread() loop,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL for-2.0 38/51] dmg: use appropriate types when reading chunks, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 39/51] dmg: sanitize chunk length and sectorcount (CVE-2014-0145), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 41/51] dmg: prevent chunk buffer overflow (CVE-2014-0145), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 42/51] block: vdi bounds check qemu-io tests, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 40/51] dmg: use uint64_t consistently for sectors and lengths, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 44/51] qcow2: Fix copy_sectors() with VM state, Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 43/51] block: Limit request size (CVE-2014-0143), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 45/51] qcow2: Fix NULL dereference in qcow2_open() error path (CVE-2014-0146), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 46/51] qcow2: Fix L1 allocation size in qcow2_snapshot_load_tmp() (CVE-2014-0145), Stefan Hajnoczi, 2014/04/01
- [Qemu-devel] [PULL for-2.0 47/51] qcow2: Check maximum L1 size in qcow2_snapshot_load_tmp() (CVE-2014-0143), Stefan Hajnoczi, 2014/04/01