- path = resolve_ref(git_path("%s", refname), currsha1, !!oldval);
- if (!path)
- die("No such ref: %s", refname);
-
- if (oldval) {
- if (memcmp(currsha1, oldsha1, 20))
- die("Ref %s is at %s but expected %s", refname, sha1_to_hex(currsha1), sha1_to_hex(oldsha1));
- /* Nothing to do? */
- if (!memcmp(oldsha1, sha1, 20))
- exit(0);
- }
- path = strdup(path);
- lockpath = mkpath("%s.lock", path);
- if (safe_create_leading_directories(lockpath) < 0)
- die("Unable to create all of %s", lockpath);
-
- fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
- if (fd < 0)
- die("Unable to create %s", lockpath);
- hex = sha1_to_hex(sha1);
- hex[40] = '\n';
- written = write(fd, hex, 41);
- close(fd);
- if (written != 41) {
- unlink(lockpath);
- die("Unable to write to %s", lockpath);
- }
-
- /*
- * Re-read the ref after getting the lock to verify
- */
- if (oldval && re_verify(path, oldsha1, currsha1) < 0) {
- unlink(lockpath);
- die("Ref lock failed");
- }
-
- /*
- * Finally, replace the old ref with the new one
- */
- if (rename(lockpath, path) < 0) {
- unlink(lockpath);
- die("Unable to create %s", path);
- }