+ revlist.in = -1;
+
+ err = start_command(&revlist);
+ if (err) {
+ error("could not run rev-list");
+ return err;
+ }
+
+ /*
+ * If rev-list --stdin encounters an unknown commit, it terminates,
+ * which will cause SIGPIPE in the write loop below.
+ */
+ sigchain_push(SIGPIPE, SIG_IGN);
+
+ for (ref = ref_map; ref; ref = ref->next) {
+ if (write_in_full(revlist.in, sha1_to_hex(ref->old_sha1), 40) < 0 ||
+ write_str_in_full(revlist.in, "\n") < 0) {
+ if (errno != EPIPE && errno != EINVAL)
+ error("failed write to rev-list: %s", strerror(errno));
+ err = -1;
+ break;
+ }
+ }
+
+ if (close(revlist.in)) {
+ error("failed to close rev-list's stdin: %s", strerror(errno));
+ err = -1;
+ }
+
+ sigchain_pop(SIGPIPE);