[Qemu-devel] [PATCH] allow reading variable size vmdk descriptor files

[Evgeny Budilovsky]

The hard-coded 2k buffer on the stack won't allow reading big descriptor

files which can be generated when storing big images (For example 500G

vmdk splitted to 2G chunks).

Signed-off-by: Evgeny Budilovsky <address@hidden>

---

 block/vmdk.c |   28 +++++++++++++++++++++-------

 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c

index 608daaf..1bc944b 100644

--- a/block/vmdk.c

+++ b/block/vmdk.c

@@ -719,27 +719,41 @@ static int vmdk_open_desc_file(BlockDriverState *bs, int flags,

                                int64_t desc_offset)

 {

     int ret;

-    char buf[2048];

+    char *buf = NULL;

     char ct[128];

     BDRVVmdkState *s = bs->opaque;

+    int64_t size;

-    ret = bdrv_pread(bs->file, desc_offset, buf, sizeof(buf));

+    size = bdrv_get_allocated_file_size(bs);

+    if (size < 0) {

+        return -EINVAL;

+    }

+

+    buf = g_malloc0(size+1);

+

+    ret = bdrv_pread(bs->file, desc_offset, buf, size);

     if (ret < 0) {

-        return ret;

+        goto exit;

     }

-    buf[2047] = '\0';

     if (vmdk_parse_description(buf, "createType", ct, sizeof(ct))) {

-        return -EMEDIUMTYPE;

+        ret = -EMEDIUMTYPE;

+        goto exit;

     }

     if (strcmp(ct, "monolithicFlat") &&

         strcmp(ct, "twoGbMaxExtentSparse") &&

         strcmp(ct, "twoGbMaxExtentFlat")) {

         fprintf(stderr,

                 "VMDK: Not supported image type \"%s\""".\n", ct);

-        return -ENOTSUP;

+        ret = -ENOTSUP;

+        goto exit;

     }

     s->desc_offset = 0;

-    return vmdk_parse_extents(buf, bs, bs->file->filename);

+    ret = vmdk_parse_extents(buf, bs, bs->file->filename);

+exit:

+    if (buf) {

+        g_free(buf);

+    }

+    return ret;

 }

 static int vmdk_open(BlockDriverState *bs, QDict *options, int flags)

--

1.7.9.5