replace trivial malloc + sprintf / strcpy calls with xstrfmt

It's a common pattern to do:

  foo = xmalloc(strlen(one) + strlen(two) + 1 + 1);
  sprintf(foo, "%s %s", one, two);

(or possibly some variant with strcpy()s or a more
complicated length computation).  We can switch these to use
xstrfmt, which is shorter, involves less error-prone manual
computation, and removes many sprintf and strcpy calls which
make it harder to audit the code for real buffer overflows.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/reflog-walk.c b/reflog-walk.c
index f8e743a23b..85b8a54241 100644
--- a/reflog-walk.c
+++ b/reflog-walk.c
@@ -56,12 +56,11 @@ static struct complete_reflogs *read_complete_reflog(const char *ref)
 		}
 	}
 	if (reflogs->nr == 0) {
-		int len = strlen(ref);
-		char *refname = xmalloc(len + 12);
-		sprintf(refname, "refs/%s", ref);
+		char *refname = xstrfmt("refs/%s", ref);
 		for_each_reflog_ent(refname, read_one_reflog, reflogs);
 		if (reflogs->nr == 0) {
-			sprintf(refname, "refs/heads/%s", ref);
+			free(refname);
+			refname = xstrfmt("refs/heads/%s", ref);
 			for_each_reflog_ent(refname, read_one_reflog, reflogs);
 		}
 		free(refname);