From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49921) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YC8y0-0001gO-Mn for qemu-devel@nongnu.org; Fri, 16 Jan 2015 10:37:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YC8xz-0000jQ-Go for qemu-devel@nongnu.org; Fri, 16 Jan 2015 10:37:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46995) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YC8xz-0000j1-9x for qemu-devel@nongnu.org; Fri, 16 Jan 2015 10:37:43 -0500 From: Stefan Hajnoczi Date: Fri, 16 Jan 2015 15:37:07 +0000 Message-Id: <1421422633-25536-11-git-send-email-stefanha@redhat.com> In-Reply-To: <1421422633-25536-1-git-send-email-stefanha@redhat.com> References: <1421422633-25536-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PULL 10/16] block/dmg: use SectorNumber from BLKX header List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Peter Wu , Stefan Hajnoczi From: Peter Wu 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 Reviewed-by: John Snow Message-id: 1420566495-13284-10-git-send-email-peter@lekensteyn.nl Signed-off-by: Stefan Hajnoczi --- 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