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[Qemu-devel] [PATCH v2] allow reading variable size vmdk descriptor file
From: |
Evgeny Budilovsky |
Subject: |
[Qemu-devel] [PATCH v2] allow reading variable size vmdk descriptor files |
Date: |
Wed, 12 Jun 2013 14:06:30 +0300 |
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 | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/block/vmdk.c b/block/vmdk.c
index 608daaf..751b63b 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -719,27 +719,40 @@ 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_getlength(bs->file);
+ if (size < 0) {
+ return -EINVAL;
+ }
+
+ size = MIN(size, 1 << 20); /* avoid unbounded allocation */
+ 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:
+ g_free(buf);
+ return ret;
}
static int vmdk_open(BlockDriverState *bs, QDict *options, int flags)
--
1.7.9.5