qemu-img: initialize MapEntry object
Commit 16b0d555 introduced an issue where we are not initializing
has_filename for the 'next' MapEntry object, which leads to interesting
errors in both Valgrind and Clang -fsanitize=undefined.
Zero the stack object at allocation AND make sure the utility to
populate the fields properly marks has_filename as false if applicable.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qemu-img.c b/qemu-img.c
index 7030107..fb9ab1f 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2194,6 +2194,7 @@
int64_t ret;
int depth;
BlockDriverState *file;
+ bool has_offset;
/* As an optimization, we could cache the current range of unallocated
* clusters in each file of the chain, and avoid querying the same
@@ -2220,17 +2221,20 @@
depth++;
}
- e->start = sector_num * BDRV_SECTOR_SIZE;
- e->length = nb_sectors * BDRV_SECTOR_SIZE;
- e->data = !!(ret & BDRV_BLOCK_DATA);
- e->zero = !!(ret & BDRV_BLOCK_ZERO);
- e->offset = ret & BDRV_BLOCK_OFFSET_MASK;
- e->has_offset = !!(ret & BDRV_BLOCK_OFFSET_VALID);
- e->depth = depth;
- if (file && e->has_offset) {
- e->has_filename = true;
- e->filename = file->filename;
- }
+ has_offset = !!(ret & BDRV_BLOCK_OFFSET_VALID);
+
+ *e = (MapEntry) {
+ .start = sector_num * BDRV_SECTOR_SIZE,
+ .length = nb_sectors * BDRV_SECTOR_SIZE,
+ .data = !!(ret & BDRV_BLOCK_DATA),
+ .zero = !!(ret & BDRV_BLOCK_ZERO),
+ .offset = ret & BDRV_BLOCK_OFFSET_MASK,
+ .has_offset = has_offset,
+ .depth = depth,
+ .has_filename = file && has_offset,
+ .filename = file && has_offset ? file->filename : NULL,
+ };
+
return 0;
}
