From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40861) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XmpNy-0005z1-PQ for qemu-devel@nongnu.org; Fri, 07 Nov 2014 14:40:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XmpNs-0004FV-Iu for qemu-devel@nongnu.org; Fri, 07 Nov 2014 14:39:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58806) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XmpNs-0004FR-8Q for qemu-devel@nongnu.org; Fri, 07 Nov 2014 14:39:48 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sA7JdloW018360 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Fri, 7 Nov 2014 14:39:47 -0500 From: Kevin Wolf Date: Fri, 7 Nov 2014 20:39:22 +0100 Message-Id: <1415389165-16157-7-git-send-email-kwolf@redhat.com> In-Reply-To: <1415389165-16157-1-git-send-email-kwolf@redhat.com> References: <1415389165-16157-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH v2 6/9] block: Read only one sector for format probing List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, jcody@redhat.com, armbru@redhat.com, mreitz@redhat.com, stefanha@redhat.com 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 Reviewed-by: Stefan Hajnoczi --- block.c | 2 +- include/block/block_int.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 2fdc33f..1fd4b8e 100644 --- a/block.c +++ b/block.c @@ -682,7 +682,7 @@ 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