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[Qemu-devel] [PATCH 2/4] vmdk: Read footer for streamOptimized images
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 2/4] vmdk: Read footer for streamOptimized images |
Date: |
Fri, 17 Aug 2012 21:25:06 +0200 |
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>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Reviewed-by: Jeff Cody <address@hidden>
---
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) {
--
1.7.6.5