int cmd_upload_archive(int argc, const char **argv, const char *prefix)
{
	const char *sent_argv[MAX_ARGS];
	struct child_process cld = { sent_argv };
	cld.out = cld.err = -1;
	cld.git_cmd = 1;

	if (argc != 2)
		usage(upload_archive_usage);

	if (!enter_repo(argv[1], 0))
		die("'%s' does not appear to be a git repository", argv[1]);

	prepare_argv(sent_argv, argv);
	if (start_command(&cld)) {
		int err = errno;
		packet_write(1, "NACK fork failed on the remote side\n");
		die("upload-archive: %s", strerror(err));
	}

	/* parent - read from child, multiplex and send out to fd#1 */
	packet_write(1, "ACK\n");
	packet_flush(1);

	while (1) {
		struct pollfd pfd[2];
		int status;

		pfd[0].fd = cld.out;
		pfd[0].events = POLLIN;
		pfd[1].fd = cld.err;
		pfd[1].events = POLLIN;
		if (poll(pfd, 2, -1) < 0) {
			if (errno != EINTR) {
				error("poll failed resuming: %s",
				      strerror(errno));
				sleep(1);
			}
			continue;
		}
		if (pfd[1].revents & POLLIN)
			/* Status stream ready */
			if (process_input(pfd[1].fd, 2))
				continue;
		if (pfd[0].revents & POLLIN)
			/* Data stream ready */
			if (process_input(pfd[0].fd, 1))
				continue;

		if (waitpid(cld.pid, &status, 0) < 0)
			error_clnt("%s", lostchild);
		else if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
			error_clnt("%s", deadchild);
		packet_flush(1);
		break;
	}
	return 0;
}

static struct ref *do_fetch_pack(int fd[2],
		const struct ref *orig_ref,
		int nr_match,
		char **match,
		char **pack_lockfile)
{
	struct ref *ref = copy_ref_list(orig_ref);
	unsigned char sha1[20];

	if (is_repository_shallow() && !server_supports("shallow"))
		die("Server does not support shallow clients");
	if (server_supports("multi_ack_detailed")) {
		if (args.verbose)
			fprintf(stderr, "Server supports multi_ack_detailed\n");
		multi_ack = 2;
	}
	else if (server_supports("multi_ack")) {
		if (args.verbose)
			fprintf(stderr, "Server supports multi_ack\n");
		multi_ack = 1;
	}
	if (server_supports("side-band-64k")) {
		if (args.verbose)
			fprintf(stderr, "Server supports side-band-64k\n");
		use_sideband = 2;
	}
	else if (server_supports("side-band")) {
		if (args.verbose)
			fprintf(stderr, "Server supports side-band\n");
		use_sideband = 1;
	}
	if (server_supports("ofs-delta")) {
		if (args.verbose)
			fprintf(stderr, "Server supports ofs-delta\n");
	} else
		prefer_ofs_delta = 0;
	if (everything_local(&ref, nr_match, match)) {
		packet_flush(fd[1]);
		goto all_done;
	}
	if (find_common(fd, sha1, ref) < 0)
		if (!args.keep_pack)
			/* When cloning, it is not unusual to have
			 * no common commit.
			 */
			warning("no common commits");

	if (args.stateless_rpc)
		packet_flush(fd[1]);
	if (get_pack(fd, pack_lockfile))
		die("git fetch-pack: fetch failed.");

 all_done:
	return ref;
}

int cmd_upload_archive(int argc, const char **argv, const char *prefix)
{
	struct child_process writer = { argv };

	/*
	 * Set up sideband subprocess.
	 *
	 * We (parent) monitor and read from child, sending its fd#1 and fd#2
	 * multiplexed out to our fd#1.  If the child dies, we tell the other
	 * end over channel #3.
	 */
	argv[0] = "upload-archive--writer";
	writer.out = writer.err = -1;
	writer.git_cmd = 1;
	if (start_command(&writer)) {
		int err = errno;
		packet_write(1, "NACK unable to spawn subprocess\n");
		die("upload-archive: %s", strerror(err));
	}

	packet_write(1, "ACK\n");
	packet_flush(1);

	while (1) {
		struct pollfd pfd[2];

		pfd[0].fd = writer.out;
		pfd[0].events = POLLIN;
		pfd[1].fd = writer.err;
		pfd[1].events = POLLIN;
		if (poll(pfd, 2, -1) < 0) {
			if (errno != EINTR) {
				error("poll failed resuming: %s",
				      strerror(errno));
				sleep(1);
			}
			continue;
		}
		if (pfd[1].revents & POLLIN)
			/* Status stream ready */
			if (process_input(pfd[1].fd, 2))
				continue;
		if (pfd[0].revents & POLLIN)
			/* Data stream ready */
			if (process_input(pfd[0].fd, 1))
				continue;

		if (finish_command(&writer))
			error_clnt("%s", deadchild);
		packet_flush(1);
		break;
	}
	return 0;
}

struct ref *fetch_pack(struct fetch_pack_args *args,
		       int fd[], struct child_process *conn,
		       const struct ref *ref,
		       const char *dest,
		       struct ref **sought, int nr_sought,
		       struct sha1_array *shallow,
		       char **pack_lockfile)
{
	struct ref *ref_cpy;
	struct shallow_info si;

	fetch_pack_setup();
	if (nr_sought)
		nr_sought = remove_duplicates_in_refs(sought, nr_sought);

	if (!ref) {
		packet_flush(fd[1]);
		die("no matching remote head");
	}
	prepare_shallow_info(&si, shallow);
	ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
				&si, pack_lockfile);
	reprepare_packed_git();
	update_shallow(args, sought, nr_sought, &si);
	clear_shallow_info(&si);
	return ref_cpy;
}

static void upload_pack(void)
{
	struct string_list symref = STRING_LIST_INIT_DUP;

	head_ref_namespaced(find_symref, &symref);

	if (advertise_refs || !stateless_rpc) {
		reset_timeout();
		head_ref_namespaced(send_ref, &symref);
		for_each_namespaced_ref(send_ref, &symref);
		advertise_shallow_grafts(1);
		packet_flush(1);
	} else {
		head_ref_namespaced(mark_our_ref, NULL);
		for_each_namespaced_ref(mark_our_ref, NULL);
	}
	string_list_clear(&symref, 1);
	if (advertise_refs)
		return;

	receive_needs();
	if (want_obj.nr) {
		get_common_commits();
		create_pack_file();
	}
}

void upload_pack(struct upload_pack_options *options)
{
	struct string_list symref = STRING_LIST_INIT_DUP;

	stateless_rpc = options->stateless_rpc;
	timeout = options->timeout;
	daemon_mode = options->daemon_mode;

	git_config(upload_pack_config, NULL);

	head_ref_namespaced(find_symref, &symref);

	if (options->advertise_refs || !stateless_rpc) {
		reset_timeout();
		head_ref_namespaced(send_ref, &symref);
		for_each_namespaced_ref(send_ref, &symref);
		advertise_shallow_grafts(1);
		packet_flush(1);
	} else {
		head_ref_namespaced(check_ref, NULL);
		for_each_namespaced_ref(check_ref, NULL);
	}
	string_list_clear(&symref, 1);
	if (options->advertise_refs)
		return;

	receive_needs();
	if (want_obj.nr) {
		get_common_commits();
		create_pack_file();
	}
}

static void deepen(int depth, int deepen_relative,
		   struct object_array *shallows)
{
	if (depth == INFINITE_DEPTH && !is_repository_shallow()) {
		int i;

		for (i = 0; i < shallows->nr; i++) {
			struct object *object = shallows->objects[i].item;
			object->flags |= NOT_SHALLOW;
		}
	} else if (deepen_relative) {
		struct object_array reachable_shallows = OBJECT_ARRAY_INIT;
		struct commit_list *result;

		get_reachable_list(shallows, &reachable_shallows);
		result = get_shallow_commits(&reachable_shallows,
					     depth + 1,
					     SHALLOW, NOT_SHALLOW);
		send_shallow(result);
		free_commit_list(result);
		object_array_clear(&reachable_shallows);
	} else {
		struct commit_list *result;

		result = get_shallow_commits(&want_obj, depth,
					     SHALLOW, NOT_SHALLOW);
		send_shallow(result);
		free_commit_list(result);
	}

	send_unshallow(shallows);
	packet_flush(1);
}

static void get_info_refs(char *arg)
{
	const char *service_name = get_parameter("service");
	struct strbuf buf = STRBUF_INIT;

	hdr_nocache();

	if (service_name) {
		const char *argv[] = {NULL /* service name */,
			"--stateless-rpc", "--advertise-refs",
			".", NULL};
		struct rpc_service *svc = select_service(service_name);

		strbuf_addf(&buf, "application/x-git-%s-advertisement",
			svc->name);
		hdr_str(content_type, buf.buf);
		end_headers();

		packet_write(1, "# service=git-%s\n", svc->name);
		packet_flush(1);

		argv[0] = svc->name;
		run_service(argv);

	} else {
		select_getanyfile();
		for_each_namespaced_ref(show_text_ref, &buf);
		send_strbuf("text/plain", &buf);
	}
	strbuf_release(&buf);
}

struct ref *fetch_pack(struct fetch_pack_args *args,
		       int fd[], struct child_process *conn,
		       const struct ref *ref,
		       const char *dest,
		       struct ref **sought, int nr_sought,
		       char **pack_lockfile)
{
	struct ref *ref_cpy;

	fetch_pack_setup();
	if (nr_sought)
		nr_sought = remove_duplicates_in_refs(sought, nr_sought);

	if (!ref) {
		packet_flush(fd[1]);
		die("no matching remote head");
	}
	ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought, pack_lockfile);

	if (args->depth > 0 && alternate_shallow_file) {
		if (*alternate_shallow_file == '\0') { /* --unshallow */
			unlink_or_warn(git_path("shallow"));
			rollback_lock_file(&shallow_lock);
		} else
			commit_lock_file(&shallow_lock);
	}

	reprepare_packed_git();
	return ref_cpy;
}

struct ref *fetch_pack(struct fetch_pack_args *my_args,
		       int fd[], struct child_process *conn,
		       const struct ref *ref,
		const char *dest,
		int nr_heads,
		char **heads,
		char **pack_lockfile)
{
	struct stat st;
	struct ref *ref_cpy;

	fetch_pack_setup();
	if (&args != my_args)
		memcpy(&args, my_args, sizeof(args));
	if (args.depth > 0) {
		if (stat(git_path("shallow"), &st))
			st.st_mtime = 0;
	}

	if (heads && nr_heads)
		nr_heads = remove_duplicates(nr_heads, heads);
	if (!ref) {
		packet_flush(fd[1]);
		die("no matching remote head");
	}
	ref_cpy = do_fetch_pack(fd, ref, nr_heads, heads, pack_lockfile);

	if (args.depth > 0) {
		struct cache_time mtime;
		struct strbuf sb = STRBUF_INIT;
		char *shallow = git_path("shallow");
		int fd;

		mtime.sec = st.st_mtime;
		mtime.nsec = ST_MTIME_NSEC(st);
		if (stat(shallow, &st)) {
			if (mtime.sec)
				die("shallow file was removed during fetch");
		} else if (st.st_mtime != mtime.sec
#ifdef USE_NSEC
				|| ST_MTIME_NSEC(st) != mtime.nsec
#endif
			  )
			die("shallow file was changed during fetch");

		fd = hold_lock_file_for_update(&lock, shallow,
					       LOCK_DIE_ON_ERROR);
		if (!write_shallow_commits(&sb, 0)
		 || write_in_full(fd, sb.buf, sb.len) != sb.len) {
			unlink_or_warn(shallow);
			rollback_lock_file(&lock);
		} else {
			commit_lock_file(&lock);
		}
		strbuf_release(&sb);
	}

	reprepare_packed_git();
	return ref_cpy;
}

static void send_request(int fd, struct strbuf *buf)
{
	if (args.stateless_rpc) {
		send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
		packet_flush(fd);
	} else
		safe_write(fd, buf->buf, buf->len);
}

int cmd_receive_pack(int argc, const char **argv, const char *prefix)
{
	int i;
	char *dir = NULL;

	argv++;
	for (i = 1; i < argc; i++) {
		const char *arg = *argv++;

		if (*arg == '-') {
			/* Do flag handling here */
			usage(receive_pack_usage);
		}
		if (dir)
			usage(receive_pack_usage);
		dir = xstrdup(arg);
	}
	if (!dir)
		usage(receive_pack_usage);

	setup_path();

	if (!enter_repo(dir, 0))
		die("'%s': unable to chdir or not a git archive", dir);

	if (is_repository_shallow())
		die("attempt to push into a shallow repository");

	git_config(receive_pack_config, NULL);

	if (0 <= transfer_unpack_limit)
		unpack_limit = transfer_unpack_limit;
	else if (0 <= receive_unpack_limit)
		unpack_limit = receive_unpack_limit;

	add_alternate_refs();
	write_head_info();
	clear_extra_refs();

	/* EOF */
	packet_flush(1);

	read_head_info();
	if (commands) {
		const char *unpack_status = NULL;

		if (!delete_only(commands))
			unpack_status = unpack();
		execute_commands(unpack_status);
		if (pack_lockfile)
			unlink(pack_lockfile);
		if (report_status)
			report(unpack_status);
		run_receive_hook(post_receive_hook);
		run_update_post_hook(commands);
	}
	return 0;
}

struct ref *fetch_pack(struct fetch_pack_args *my_args,
		       int fd[], struct child_process *conn,
		       const struct ref *ref,
		const char *dest,
		int nr_heads,
		char **heads,
		char **pack_lockfile)
{
	struct stat st;
	struct ref *ref_cpy;

	fetch_pack_setup();
	memcpy(&args, my_args, sizeof(args));
	if (args.depth > 0) {
		if (stat(git_path("shallow"), &st))
			st.st_mtime = 0;
	}

	if (heads && nr_heads)
		nr_heads = remove_duplicates(nr_heads, heads);
	if (!ref) {
		packet_flush(fd[1]);
		die("no matching remote head");
	}
	ref_cpy = do_fetch_pack(fd, ref, nr_heads, heads, pack_lockfile);

	if (args.depth > 0) {
		struct cache_time mtime;
		char *shallow = git_path("shallow");
		int fd;

		mtime.sec = st.st_mtime;
#ifdef USE_NSEC
		mtime.usec = st.st_mtim.usec;
#endif
		if (stat(shallow, &st)) {
			if (mtime.sec)
				die("shallow file was removed during fetch");
		} else if (st.st_mtime != mtime.sec
#ifdef USE_NSEC
				|| st.st_mtim.usec != mtime.usec
#endif
			  )
			die("shallow file was changed during fetch");

		fd = hold_lock_file_for_update(&lock, shallow, 1);
		if (!write_shallow_commits(fd, 0)) {
			unlink(shallow);
			rollback_lock_file(&lock);
		} else {
			commit_lock_file(&lock);
		}
	}

	reprepare_packed_git();
	return ref_cpy;
}

static void send_request(struct fetch_pack_args *args,
			 int fd, struct strbuf *buf)
{
	if (args->stateless_rpc) {
		send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
		packet_flush(fd);
	} else
		write_or_die(fd, buf->buf, buf->len);
}

static void deepen_by_rev_list(int ac, const char **av,
			       struct object_array *shallows)
{
	struct commit_list *result;

	result = get_shallow_commits_by_rev_list(ac, av, SHALLOW, NOT_SHALLOW);
	send_shallow(result);
	free_commit_list(result);
	send_unshallow(shallows);
	packet_flush(1);
}

static void upload_pack(void)
{
	reset_timeout();
	head_ref(send_ref, NULL);
	for_each_ref(send_ref, NULL);
	packet_flush(1);
	receive_needs();
	if (want_obj.nr) {
		get_common_commits();
		create_pack_file();
	}
}

/*
 * Serialize the list of changes to the given file.  The goal of this
 * is to just serialize the key fields in wt_status so that a
 * later command can rebuilt it and do the printing.
 *
 * We DO NOT include the contents of wt_status_state NOR
 * current branch info.  This info easily gets stale and
 * is relatively quick for the status consumer to compute
 * as necessary.
 */
void wt_status_serialize_v1(int fd, struct wt_status *s)
{
	struct string_list_item *iter;
	int k;

	/*
	 * version header must be first line.
	 */
	packet_write_fmt(fd, "version 1\n");

	wt_serialize_v1_header(s, fd);

	if (s->change.nr > 0) {
		packet_write_fmt(fd, "changed %d\n", s->change.nr);
		for (k = 0; k < s->change.nr; k++) {
			iter = &(s->change.items[k]);
			wt_serialize_v1_changed(s, fd, iter);
		}
		packet_flush(fd);
	}

	if (s->untracked.nr > 0) {
		packet_write_fmt(fd, "untracked %d\n", s->untracked.nr);
		for (k = 0; k < s->untracked.nr; k++) {
			iter = &(s->untracked.items[k]);
			wt_serialize_v1_untracked(s, fd, iter);
		}
		packet_flush(fd);
	}

	if (s->ignored.nr > 0) {
		packet_write_fmt(fd, "ignored %d\n", s->ignored.nr);
		for (k = 0; k < s->ignored.nr; k++) {
			iter = &(s->ignored.items[k]);
			wt_serialize_v1_ignored(s, fd, iter);
		}
		packet_flush(fd);
	}
}

static void write_head_info(void)
{
	struct sha1_array sa = SHA1_ARRAY_INIT;
	for_each_alternate_ref(collect_one_alternate_ref, &sa);
	sha1_array_for_each_unique(&sa, show_one_alternate_sha1, NULL);
	sha1_array_clear(&sa);
	for_each_ref(show_ref_cb, NULL);
	if (!sent_capabilities)
		show_ref("capabilities^{}", null_sha1);

	/* EOF */
	packet_flush(1);
}

static int disconnect_git(struct transport *transport)
{
	struct git_transport_data *data = transport->data;
	if (data->conn) {
		packet_flush(data->fd[1]);
		close(data->fd[0]);
		close(data->fd[1]);
		finish_connect(data->conn);
	}

	free(data);
	return 0;
}

/*
 * Write V1 header fields.
 */
static void wt_serialize_v1_header(struct wt_status *s, int fd)
{
	/*
	 * Write select fields from the current index to help
	 * the deserializer recognize a stale data set.
	 */
	packet_write_fmt(fd, "index_mtime %d %d\n",
			 the_index.timestamp.sec,
			 the_index.timestamp.nsec);

	/*
	 * Write data from wt_status to qualify this status report.
	 * That is, if this run specified "-uno", the consumer of
	 * our serialization should know that.
	 */
	packet_write_fmt(fd, "is_initial %d\n", s->is_initial);
	if (s->branch)
		packet_write_fmt(fd, "branch %s\n", s->branch);
	if (s->reference)
		packet_write_fmt(fd, "reference %s\n", s->reference);
	/* pathspec */
	/* verbose */
	/* amend */
	packet_write_fmt(fd, "whence %d\n", s->whence);
	/* nowarn */
	/* use_color */
	/* no_gettext */
	/* display_comment_prefix */
	/* relative_paths */
	/* submodule_summary */
	packet_write_fmt(fd, "show_ignored_mode %d\n", s->show_ignored_mode);
	packet_write_fmt(fd, "show_untracked_files %d\n", s->show_untracked_files);
	if (s->ignore_submodule_arg)
		packet_write_fmt(fd, "ignore_submodule_arg %s\n", s->ignore_submodule_arg);
	/* color_palette */
	/* colopts */
	/* null_termination */
	/* commit_template */
	/* show_branch */
	/* show_stash */
	packet_write_fmt(fd, "hints %d\n", s->hints);
	packet_write_fmt(fd, "detect_rename %d\n", s->detect_rename);
	packet_write_fmt(fd, "rename_score %d\n", s->rename_score);
	packet_write_fmt(fd, "rename_limit %d\n", s->rename_limit);
	/* status_format */
	packet_write_fmt(fd, "sha1_commit %s\n", sha1_to_hex(s->sha1_commit));
	packet_write_fmt(fd, "commitable %d\n", s->commitable);
	packet_write_fmt(fd, "workdir_dirty %d\n", s->workdir_dirty);
	/* prefix */
	packet_flush(fd);
}