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[Qemu-devel] [PATCH v3 6/9] block: Read only one sector for format probi
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH v3 6/9] block: Read only one sector for format probing |
Date: |
Thu, 20 Nov 2014 16:27:11 +0100 |
The only image format driver that even potentially accesses anything
after 512 bytes in its bdrv_probe() implementation is VMDK, which reads
a plain-text descriptor file. In practice, the field it's looking for
seems to come first and will be well within the first 512 bytes, too.
Signed-off-by: Kevin Wolf <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
---
block.c | 6 +++---
include/block/block_int.h | 2 ++
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/block.c b/block.c
index a0051cb..9114cfa 100644
--- a/block.c
+++ b/block.c
@@ -654,8 +654,8 @@ BlockDriver *bdrv_find_protocol(const char *filename,
* we do it anyway for backward compatibility.
*
* @buf contains the image's first @buf_size bytes.
- * @buf_size is the buffer size in bytes (generally 2048, but can be smaller
- * if the image file is smaller)
+ * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE,
+ * but can be smaller if the image file is smaller)
* @filename is its filename.
*
* For all block drivers, call the bdrv_probe() method to get its
@@ -685,7 +685,7 @@ static int find_image_format(BlockDriverState *bs, const
char *filename,
BlockDriver **pdrv, Error **errp)
{
BlockDriver *drv;
- uint8_t buf[2048];
+ uint8_t buf[BLOCK_PROBE_BUF_SIZE];
int ret = 0;
/* Return the raw BlockDriver * to scsi-generic devices or empty drives */
diff --git a/include/block/block_int.h b/include/block/block_int.h
index a1c17b9..cd94559 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -57,6 +57,8 @@
#define BLOCK_OPT_REDUNDANCY "redundancy"
#define BLOCK_OPT_NOCOW "nocow"
+#define BLOCK_PROBE_BUF_SIZE 512
+
typedef struct BdrvTrackedRequest {
BlockDriverState *bs;
int64_t offset;
--
1.8.3.1
- [Qemu-devel] [PATCH v3 0/9] raw: Prohibit dangerous writes for probed images, Kevin Wolf, 2014/11/20
- [Qemu-devel] [PATCH v3 1/9] qemu-io: Allow explicitly specifying format, Kevin Wolf, 2014/11/20
- [Qemu-devel] [PATCH v3 2/9] qemu-iotests: Use qemu-io -f $IMGFMT, Kevin Wolf, 2014/11/20
- [Qemu-devel] [PATCH v3 3/9] qemu-iotests: Add qemu-io format option in Python tests, Kevin Wolf, 2014/11/20
- [Qemu-devel] [PATCH v3 4/9] qtests: Specify image format explicitly, Kevin Wolf, 2014/11/20
- [Qemu-devel] [PATCH v3 5/9] block: Factor bdrv_probe_all() out of find_image_format(), Kevin Wolf, 2014/11/20
- [Qemu-devel] [PATCH v3 6/9] block: Read only one sector for format probing,
Kevin Wolf <=
- [Qemu-devel] [PATCH v3 7/9] raw: Prohibit dangerous writes for probed images, Kevin Wolf, 2014/11/20
- Re: [Qemu-devel] [PATCH v3 7/9] raw: Prohibit dangerous writes for probed images, Stefan Hajnoczi, 2014/11/25
- [Qemu-devel] [PATCH v3 8/9] qemu-iotests: Fix stderr handling in common.qemu, Kevin Wolf, 2014/11/20
- [Qemu-devel] [PATCH v3 9/9] qemu-iotests: Test writing non-raw image headers to raw image, Kevin Wolf, 2014/11/20
- Re: [Qemu-devel] [PATCH v3 0/9] raw: Prohibit dangerous writes for probed images, Stefan Hajnoczi, 2014/11/26