btrfs-progs: check for null string in parse_size

Because it's better than a segfault if it's called improperly,
and it makes static checkers happier.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

diff --git a/utils.c b/utils.c
index 71da787..629b40b 100644 (file)
--- a/utils.c
+++ b/utils.c
@@ -1382,7 +1382,7 @@ u64 parse_size(char *s)
        char c;
        u64 mult = 1;
 
-       for (i=0 ; s[i] && isdigit(s[i]) ; i++) ;
+       for (i = 0; s && s[i] && isdigit(s[i]); i++) ;
        if (!i) {
                fprintf(stderr, "ERROR: size value is empty\n");
                exit(50);