[libvirt] [PATCH 08/30] storagefile: Push 'start' into qcow2GetBackingStoreFormat
This is a step towards making this qcow2GetBackingStoreFormat into
a generic qcow2 extensions parser
Signed-off-by: Cole Robinson <crobinso(a)redhat.com>
---
src/util/virstoragefile.c | 33 +++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index a9a6c3e132..4a3c9df7a2 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -430,10 +430,22 @@ static int
qcow2GetBackingStoreFormat(int *format,
const char *buf,
size_t buf_size,
- size_t extension_start,
size_t extension_end)
{
- size_t offset = extension_start;
+ size_t offset;
+ size_t extension_start;
+ int version = virReadBufInt32BE(buf + QCOWX_HDR_VERSION);
+
+ if (version < 2) {
+ /* QCow1 doesn't have the extensions capability
+ * used to store backing format */
+ return 0;
+ }
+
+ if (version == 2)
+ extension_start = QCOW2_HDR_TOTAL_SIZE;
+ else
+ extension_start = virReadBufInt32BE(buf + QCOW2v3_HDR_SIZE);
/*
* The extensions take format of
@@ -445,6 +457,7 @@ qcow2GetBackingStoreFormat(int *format,
* Unknown extensions can be ignored by skipping
* over "length" bytes in the data stream.
*/
+ offset = extension_start;
while (offset < (buf_size-8) &&
offset < (extension_end-8)) {
unsigned int magic = virReadBufInt32BE(buf + offset);
@@ -487,8 +500,6 @@ qcowXGetBackingStore(char **res,
{
unsigned long long offset;
unsigned int size;
- unsigned long long start;
- int version;
*res = NULL;
*format = VIR_STORAGE_FILE_AUTO;
@@ -546,18 +557,8 @@ qcowXGetBackingStore(char **res,
* is stored at QCOW2v3_HDR_SIZE
*/
- version = virReadBufInt32BE(buf + QCOWX_HDR_VERSION);
- if (version >= 2) {
- /* QCow1 doesn't have the extensions capability
- * used to store backing format */
- if (version == 2)
- start = QCOW2_HDR_TOTAL_SIZE;
- else
- start = virReadBufInt32BE(buf + QCOW2v3_HDR_SIZE);
- if (qcow2GetBackingStoreFormat(format, buf, buf_size,
- start, offset) < 0)
- return BACKING_STORE_INVALID;
- }
+ if (qcow2GetBackingStoreFormat(format, buf, buf_size, offset) < 0)
+ return BACKING_STORE_INVALID;
return BACKING_STORE_OK;
}
--
2.23.0