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[Qemu-devel] [PULL 10/16] block/dmg: use SectorNumber from BLKX header
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 10/16] block/dmg: use SectorNumber from BLKX header |
Date: |
Fri, 16 Jan 2015 15:37:07 +0000 |
From: Peter Wu <address@hidden>
Previously the sector table parsing relied on the previous offset of
the DMG file. Now it uses the sector number from the BLKX header
(see http://newosxbook.com/DMG.html).
The implementation of dmg2img (from vu1tur) does not base the output
sector on the location of the terminator (0xffffffff) either so it
should be safe to drop this dependency on the previous state.
(It makes somehow makes sense, a terminator should halt further
processing of a block and is perhaps used to preallocate some space.)
Signed-off-by: Peter Wu <address@hidden>
Reviewed-by: John Snow <address@hidden>
Message-id: address@hidden
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block/dmg.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/block/dmg.c b/block/dmg.c
index 65fc7fe..0f278c8 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -187,7 +187,6 @@ typedef struct DmgHeaderState {
/* used internally by dmg_read_mish_block to remember offsets of blocks
* across calls */
uint64_t data_fork_offset;
- uint64_t last_out_offset;
/* exported for dmg_open */
uint32_t max_compressed_size;
uint32_t max_sectors_per_chunk;
@@ -203,6 +202,7 @@ static int dmg_read_mish_block(BDRVDMGState *s,
DmgHeaderState *ds,
int64_t offset = 0;
uint64_t data_offset;
uint64_t in_offset = ds->data_fork_offset;
+ uint64_t out_offset;
type = buff_read_uint32(buffer, offset);
/* skip data that is not a valid MISH block (invalid magic or too small) */
@@ -211,6 +211,9 @@ static int dmg_read_mish_block(BDRVDMGState *s,
DmgHeaderState *ds,
return 0;
}
+ /* chunk offsets are relative to this sector number */
+ out_offset = buff_read_uint64(buffer, offset + 8);
+
/* location in data fork for (compressed) blob (in bytes) */
data_offset = buff_read_uint64(buffer, offset + 0x18);
in_offset += data_offset;
@@ -231,10 +234,6 @@ static int dmg_read_mish_block(BDRVDMGState *s,
DmgHeaderState *ds,
offset += 4;
if (s->types[i] != 0x80000005 && s->types[i] != 1 &&
s->types[i] != 2) {
- if (s->types[i] == 0xffffffff && i > 0) {
- ds->last_out_offset = s->sectors[i - 1] +
- s->sectorcounts[i - 1];
- }
chunk_count--;
i--;
offset += 36;
@@ -243,7 +242,7 @@ static int dmg_read_mish_block(BDRVDMGState *s,
DmgHeaderState *ds,
offset += 4;
s->sectors[i] = buff_read_uint64(buffer, offset);
- s->sectors[i] += ds->last_out_offset;
+ s->sectors[i] += out_offset;
offset += 8;
s->sectorcounts[i] = buff_read_uint64(buffer, offset);
@@ -417,7 +416,6 @@ static int dmg_open(BlockDriverState *bs, QDict *options,
int flags,
s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
/* used by dmg_read_mish_block to keep track of the current I/O position */
ds.data_fork_offset = 0;
- ds.last_out_offset = 0;
ds.max_compressed_size = 1;
ds.max_sectors_per_chunk = 1;
--
2.1.0
- [Qemu-devel] [PULL 00/16] Block patches, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 01/16] block: add event when disk usage exceeds threshold, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 02/16] block/dmg: properly detect the UDIF trailer, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 03/16] block/dmg: extract mish block decoding functionality, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 04/16] block/dmg: extract processing of resource forks, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 07/16] block/dmg: process XML plists, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 05/16] block/dmg: process a buffer instead of reading ints, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 06/16] block/dmg: validate chunk size to avoid overflow, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 10/16] block/dmg: use SectorNumber from BLKX header,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 08/16] block/dmg: set virtual size to a non-zero value, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 12/16] block/dmg: support bzip2 block entry types, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 09/16] block/dmg: fix sector data offset calculation, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 14/16] qed: check for header size overflow, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 11/16] block/dmg: factor out block type check, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 15/16] qemu-iotests: add 116 invalid QED input file tests, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 13/16] block/dmg: improve zeroes handling, Stefan Hajnoczi, 2015/01/16
- [Qemu-devel] [PULL 16/16] qemu-iotests: Fix supported_oses check, Stefan Hajnoczi, 2015/01/16
- Re: [Qemu-devel] [PULL 00/16] Block patches, Peter Maydell, 2015/01/16