[PATCH 3/3] libmtd: fix segmentation fault on lib->mtd

[Brian Norris <computersforpeace@gmail.com>]

Legacy systems do not initialize lib->mtd, so we shouldn't perform
strlen(lib->mtd); this produces a segmentation fault. As this code isn't
used in the legacy codepath, we can just move it down to an 'else' branch.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
 lib/libmtd.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/lib/libmtd.c b/lib/libmtd.c
index 2bb4e57..fb4586c 100644
--- a/lib/libmtd.c
+++ b/lib/libmtd.c
@@ -644,13 +644,15 @@ void libmtd_close(libmtd_t desc)
 int mtd_dev_present(libmtd_t desc, int mtd_num) {
 	struct stat st;
 	struct libmtd *lib = (struct libmtd *)desc;
-	char file[strlen(lib->mtd) + 10];
 
 	if (!lib->sysfs_supported)
 		return legacy_dev_present(mtd_num);
+	else {
+		char file[strlen(lib->mtd) + 10];
 
-	sprintf(file, lib->mtd, mtd_num);
-	return !stat(file, &st);
+		sprintf(file, lib->mtd, mtd_num);
+		return !stat(file, &st);
+	}
 }
 
 int mtd_get_info(libmtd_t desc, struct mtd_info *info)
-- 
1.7.5.4