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Re: [Qemu-devel] [PATCH v2 2/2] vmdk: Read footer for streamOptimized im
From: |
Jeff Cody |
Subject: |
Re: [Qemu-devel] [PATCH v2 2/2] vmdk: Read footer for streamOptimized images |
Date: |
Fri, 17 Aug 2012 07:16:20 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 |
On 08/16/2012 05:50 AM, Kevin Wolf wrote:
> The footer takes precedence over the header when it exists. It contains
> the real grain directory offset that is missing in the header. Without
> this patch, streamOptimized images with a footer cannot be read.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
> v2:
> - Enough footer sanity checks, I hope? :-)
>
> block/vmdk.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 56 insertions(+), 0 deletions(-)
>
> diff --git a/block/vmdk.c b/block/vmdk.c
> index 9648398..bba4c61 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -35,6 +35,7 @@
> #define VMDK4_FLAG_RGD (1 << 1)
> #define VMDK4_FLAG_COMPRESS (1 << 16)
> #define VMDK4_FLAG_MARKER (1 << 17)
> +#define VMDK4_GD_AT_END 0xffffffffffffffffULL
>
> typedef struct {
> uint32_t version;
> @@ -115,6 +116,13 @@ typedef struct VmdkGrainMarker {
> uint8_t data[0];
> } VmdkGrainMarker;
>
> +enum {
> + MARKER_END_OF_STREAM = 0,
> + MARKER_GRAIN_TABLE = 1,
> + MARKER_GRAIN_DIRECTORY = 2,
> + MARKER_FOOTER = 3,
> +};
> +
> static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
> {
> uint32_t magic;
> @@ -451,6 +459,54 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
> if (header.capacity == 0 && header.desc_offset) {
> return vmdk_open_desc_file(bs, flags, header.desc_offset << 9);
> }
> +
> + if (le64_to_cpu(header.gd_offset) == VMDK4_GD_AT_END) {
> + /*
> + * The footer takes precedence over the header, so read it in. The
> + * footer starts at offset -1024 from the end: One sector for the
> + * footer, and another one for the end-of-stream marker.
> + */
> + struct {
> + struct {
> + uint64_t val;
> + uint32_t size;
> + uint32_t type;
> + uint8_t pad[512 - 16];
> + } QEMU_PACKED footer_marker;
> +
> + uint32_t magic;
> + VMDK4Header header;
> + uint8_t pad[512 - 4 - sizeof(VMDK4Header)];
> +
> + struct {
> + uint64_t val;
> + uint32_t size;
> + uint32_t type;
> + uint8_t pad[512 - 16];
> + } QEMU_PACKED eos_marker;
> + } QEMU_PACKED footer;
> +
> + ret = bdrv_pread(file,
> + bs->file->total_sectors * 512 - 1536,
> + &footer, sizeof(footer));
> + if (ret < 0) {
> + return ret;
> + }
> +
> + /* Some sanity checks for the footer */
> + if (be32_to_cpu(footer.magic) != VMDK4_MAGIC ||
> + le32_to_cpu(footer.footer_marker.size) != 0 ||
> + le32_to_cpu(footer.footer_marker.type) != MARKER_FOOTER ||
> + le64_to_cpu(footer.eos_marker.val) != 0 ||
> + le32_to_cpu(footer.eos_marker.size) != 0 ||
> + le32_to_cpu(footer.eos_marker.type) != MARKER_END_OF_STREAM)
> + {
> + return -EINVAL;
> + }
> +
> + header = footer.header;
> + }
> +
> l1_entry_sectors = le32_to_cpu(header.num_gtes_per_gte)
> * le64_to_cpu(header.granularity);
> if (l1_entry_sectors == 0) {
>
Reviewed-by: Jeff Cody <address@hidden>