[Qemu-devel] [PULL 08/16] block/dmg: set virtual size to a non-zero value

[Stefan Hajnoczi <stefanha@redhat.com>]

From: Peter Wu <peter@lekensteyn.nl>

Right now the virtual size is always reported as zero which makes it
impossible to convert between formats.

After this patch, the number of sectors will be read from the trailer
("koly" block).

To verify the behavior, the output of `dmg2img foo.dmg foo.img` was
compared against `qemu-img convert -f dmg -O raw foo.dmg foo.raw`. The
tests showed that the file contents are exactly the same, except that
QEMU creates a slightly larger file (it matches the total sectors
count).

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-8-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/dmg.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/block/dmg.c b/block/dmg.c
index d4a7520..3f8f1cc 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -451,6 +451,14 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
         ret = -EINVAL;
         goto fail;
     }
+    ret = read_uint64(bs, offset + 0x1ec, (uint64_t *)&bs->total_sectors);
+    if (ret < 0) {
+        goto fail;
+    }
+    if (bs->total_sectors < 0) {
+        ret = -EINVAL;
+        goto fail;
+    }
     if (rsrc_fork_length != 0) {
         ret = dmg_read_resource_fork(bs, &ds,
                                      rsrc_fork_offset, rsrc_fork_length);
-- 
2.1.0