[PATCH 2/4] sha1_file: use strncmp for string comparison

["René Scharfe" <l.s.r@web.de>]

Avoid overrunning the existing pack name (p->pack_name, a C string) in
the case that the new path is longer by using strncmp instead of memcmp
for comparing.  While at it, replace the magic constant 4 with a
strlen call to document its meaning.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
 sha1_file.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sha1_file.c b/sha1_file.c
index 0c3cada..72b8fcb 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1206,7 +1206,8 @@ static void prepare_packed_git_one(char *objdir, int local)
 		if (has_extension(de->d_name, ".idx")) {
 			/* Don't reopen a pack we already have. */
 			for (p = packed_git; p; p = p->next) {
-				if (!memcmp(path.buf, p->pack_name, path.len - 4))
+				if (!strncmp(path.buf, p->pack_name,
+					     path.len - strlen(".idx")))
 					break;
 			}
 			if (p == NULL &&
-- 
2.0.0