map_file_extents: avoid theoretical race condition

The second FS_IOC_FIEMAP call might result in a different number for
fm_mapped_extents if the file changed. So just use the size we allocated.

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/util.c b/util.c
index 709d427..874cc3d 100644
--- a/util.c
+++ b/util.c
@@ -363,8 +363,8 @@ static int map_file_extents(struct image *image, const char *filename, int f,
 		goto err_out;
 
 	/* Build extent array */
-	*extent_count = fiemap->fm_mapped_extents;
-	*extents = xzalloc(fiemap->fm_mapped_extents * sizeof(struct extent));
+	*extent_count = fiemap->fm_extent_count;
+	*extents = xzalloc(*extent_count * sizeof(struct extent));
 	for (i = 0; i < fiemap->fm_mapped_extents; i++) {
 		(*extents)[i].start = fiemap->fm_extents[i].fe_logical;
 		(*extents)[i].end = fiemap->fm_extents[i].fe_logical + fiemap->fm_extents[i].fe_length;