bdrv_img_create: Fix segfault
Block drivers that don't support creating images don't have a size option. Fail
gracefully instead of segfaulting when trying to access the option's value.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 3036a2d..24a25d5 100644
--- a/block.c
+++ b/block.c
@@ -2881,7 +2881,7 @@
char *options, uint64_t img_size, int flags)
{
QEMUOptionParameter *param = NULL, *create_options = NULL;
- QEMUOptionParameter *backing_fmt, *backing_file;
+ QEMUOptionParameter *backing_fmt, *backing_file, *size;
BlockDriverState *bs = NULL;
BlockDriver *drv, *proto_drv;
BlockDriver *backing_drv = NULL;
@@ -2964,7 +2964,8 @@
// The size for the image must always be specified, with one exception:
// If we are using a backing file, we can obtain the size from there
- if (get_option_parameter(param, BLOCK_OPT_SIZE)->value.n == -1) {
+ size = get_option_parameter(param, BLOCK_OPT_SIZE);
+ if (size && size->value.n == -1) {
if (backing_file && backing_file->value.s) {
uint64_t size;
char buf[32];
