+static int safe_append(const char *filename, const char *fmt, ...)
+{
+ va_list ap;
+ struct lock_file lock = LOCK_INIT;
+ int fd = hold_lock_file_for_update(&lock, filename,
+ LOCK_REPORT_ON_ERROR);
+ struct strbuf buf = STRBUF_INIT;
+
+ if (fd < 0)
+ return -1;
+
+ if (strbuf_read_file(&buf, filename, 0) < 0 && errno != ENOENT) {
+ error_errno(_("could not read '%s'"), filename);
+ rollback_lock_file(&lock);
+ return -1;
+ }
+ strbuf_complete(&buf, '\n');
+ va_start(ap, fmt);
+ strbuf_vaddf(&buf, fmt, ap);
+ va_end(ap);
+
+ if (write_in_full(fd, buf.buf, buf.len) < 0) {
+ error_errno(_("could not write to '%s'"), filename);
+ strbuf_release(&buf);
+ rollback_lock_file(&lock);
+ return -1;
+ }
+ if (commit_lock_file(&lock) < 0) {
+ strbuf_release(&buf);
+ rollback_lock_file(&lock);
+ return error(_("failed to finalize '%s'"), filename);
+ }
+
+ strbuf_release(&buf);
+ return 0;
+}
+
+static int do_label(const char *name, int len)
+{
+ struct ref_store *refs = get_main_ref_store();
+ struct ref_transaction *transaction;
+ struct strbuf ref_name = STRBUF_INIT, err = STRBUF_INIT;
+ struct strbuf msg = STRBUF_INIT;
+ int ret = 0;
+ struct object_id head_oid;
+
+ if (len == 1 && *name == '#')
+ return error("Illegal label name: '%.*s'", len, name);
+
+ strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
+ strbuf_addf(&msg, "rebase -i (label) '%.*s'", len, name);
+
+ transaction = ref_store_transaction_begin(refs, &err);
+ if (!transaction) {
+ error("%s", err.buf);
+ ret = -1;
+ } else if (get_oid("HEAD", &head_oid)) {
+ error(_("could not read HEAD"));
+ ret = -1;
+ } else if (ref_transaction_update(transaction, ref_name.buf, &head_oid,
+ NULL, 0, msg.buf, &err) < 0 ||
+ ref_transaction_commit(transaction, &err)) {
+ error("%s", err.buf);
+ ret = -1;
+ }
+ ref_transaction_free(transaction);
+ strbuf_release(&err);
+ strbuf_release(&msg);
+
+ if (!ret)
+ ret = safe_append(rebase_path_refs_to_delete(),
+ "%s\n", ref_name.buf);
+ strbuf_release(&ref_name);
+
+ return ret;
+}
+
+static const char *reflog_message(struct replay_opts *opts,
+ const char *sub_action, const char *fmt, ...);
+
+static int do_reset(const char *name, int len, struct replay_opts *opts)
+{
+ struct strbuf ref_name = STRBUF_INIT;
+ struct object_id oid;
+ struct lock_file lock = LOCK_INIT;
+ struct tree_desc desc;
+ struct tree *tree;
+ struct unpack_trees_options unpack_tree_opts;
+ int ret = 0, i;
+
+ if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
+ return -1;
+
+ /* Determine the length of the label */
+ for (i = 0; i < len; i++)
+ if (isspace(name[i]))
+ len = i;
+
+ strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
+ if (get_oid(ref_name.buf, &oid) &&
+ get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
+ error(_("could not read '%s'"), ref_name.buf);
+ rollback_lock_file(&lock);
+ strbuf_release(&ref_name);
+ return -1;
+ }
+
+ memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
+ setup_unpack_trees_porcelain(&unpack_tree_opts, "reset");
+ unpack_tree_opts.head_idx = 1;
+ unpack_tree_opts.src_index = &the_index;
+ unpack_tree_opts.dst_index = &the_index;
+ unpack_tree_opts.fn = oneway_merge;
+ unpack_tree_opts.merge = 1;
+ unpack_tree_opts.update = 1;
+
+ if (read_cache_unmerged()) {
+ rollback_lock_file(&lock);
+ strbuf_release(&ref_name);
+ return error_resolve_conflict(_(action_name(opts)));
+ }
+
+ if (!fill_tree_descriptor(&desc, &oid)) {
+ error(_("failed to find tree of %s"), oid_to_hex(&oid));
+ rollback_lock_file(&lock);
+ free((void *)desc.buffer);
+ strbuf_release(&ref_name);
+ return -1;
+ }
+
+ if (unpack_trees(1, &desc, &unpack_tree_opts)) {
+ rollback_lock_file(&lock);
+ free((void *)desc.buffer);
+ strbuf_release(&ref_name);
+ return -1;
+ }
+
+ tree = parse_tree_indirect(&oid);
+ prime_cache_tree(&the_index, tree);
+
+ if (write_locked_index(&the_index, &lock, COMMIT_LOCK) < 0)
+ ret = error(_("could not write index"));
+ free((void *)desc.buffer);
+
+ if (!ret)
+ ret = update_ref(reflog_message(opts, "reset", "'%.*s'",
+ len, name), "HEAD", &oid,
+ NULL, 0, UPDATE_REFS_MSG_ON_ERR);
+
+ strbuf_release(&ref_name);
+ return ret;
+}
+