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	#include "cache.h"
	#include "transport.h"
	#include "quote.h"
	#include "run-command.h"
	#include "commit.h"
	#include "diff.h"
	#include "revision.h"
	#include "remote.h"
	#include "string-list.h"
	#include "thread-utils.h"
	#include "sigchain.h"
	#include "strvec.h"
	#include "refs.h"
	#include "refspec.h"
	#include "transport-internal.h"
	#include "protocol.h"

	static int debug;

	struct helper_data {
	const char *name;
	struct child_process *helper;
	FILE *out;
	unsigned fetch : 1,
	import : 1,
	bidi_import : 1,
	export : 1,
	option : 1,
	push : 1,
	connect : 1,
	stateless_connect : 1,
	signed_tags : 1,
	check_connectivity : 1,
	no_disconnect_req : 1,
	no_private_update : 1,
	object_format : 1;

	/*
	* As an optimization, the transport code may invoke fetch before
	* get_refs_list. If this happens, and if the transport helper doesn't
	* support connect or stateless_connect, we need to invoke
	* get_refs_list ourselves if we haven't already done so. Keep track of
	* whether we have invoked get_refs_list.
	*/
	unsigned get_refs_list_called : 1;

	char *export_marks;
	char *import_marks;
	/* These go from remote name (as in "list") to private name */
	struct refspec rs;
	/* Transport options for fetch-pack/send-pack (should one of
	* those be invoked).
	*/
	struct git_transport_options transport_options;
	};

	static void sendline(struct helper_data helper, struct strbuf buffer)
	{
	if (debug)
	fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
	if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
	die_errno(_("full write to remote helper failed"));
	}

	static int recvline_fh(FILE helper, struct strbuf buffer)
	{
	strbuf_reset(buffer);
	if (debug)
	fprintf(stderr, "Debug: Remote helper: Waiting...\n");
	if (strbuf_getline(buffer, helper) == EOF) {
	if (debug)
	fprintf(stderr, "Debug: Remote helper quit.\n");
	return 1;
	}

	if (debug)
	fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
	return 0;
	}

	static int recvline(struct helper_data helper, struct strbuf buffer)
	{
	return recvline_fh(helper->out, buffer);
	}

	static void write_constant(int fd, const char *str)
	{
	if (debug)
	fprintf(stderr, "Debug: Remote helper: -> %s", str);
	if (write_in_full(fd, str, strlen(str)) < 0)
	die_errno(_("full write to remote helper failed"));
	}

	static const char remove_ext_force(const char url)
	{
	if (url) {
	const char *colon = strchr(url, ':');
	if (colon && colon[1] == ':')
	return colon + 2;
	}
	return url;
	}

	static void do_take_over(struct transport *transport)
	{
	struct helper_data *data;
	data = (struct helper_data *)transport->data;
	transport_take_over(transport, data->helper);
	fclose(data->out);
	free(data);
	}

	static void standard_options(struct transport *t);

	static struct child_process get_helper(struct transport transport)
	{
	struct helper_data *data = transport->data;
	struct strbuf buf = STRBUF_INIT;
	struct child_process *helper;
	int duped;
	int code;

	if (data->helper)
	return data->helper;

	helper = xmalloc(sizeof(*helper));
	child_process_init(helper);
	helper->in = -1;
	helper->out = -1;
	helper->err = 0;
	strvec_pushf(&helper->args, "remote-%s", data->name);
	strvec_push(&helper->args, transport->remote->name);
	strvec_push(&helper->args, remove_ext_force(transport->url));
	helper->git_cmd = 1;
	helper->silent_exec_failure = 1;

	if (have_git_dir())
	strvec_pushf(&helper->env_array, "%s=%s",
	GIT_DIR_ENVIRONMENT, get_git_dir());

	helper->trace2_child_class = helper->args.v[0]; /* "remote-<name>" */

	code = start_command(helper);
	if (code < 0 && errno == ENOENT)
	die(_("unable to find remote helper for '%s'"), data->name);
	else if (code != 0)
	exit(code);

	data->helper = helper;
	data->no_disconnect_req = 0;
	refspec_init(&data->rs, REFSPEC_FETCH);

	/*
	* Open the output as FILE* so strbuf_getline_*() family of
	* functions can be used.
	* Do this with duped fd because fclose() will close the fd,
	* and stuff like taking over will require the fd to remain.
	*/
	duped = dup(helper->out);
	if (duped < 0)
	die_errno(_("can't dup helper output fd"));
	data->out = xfdopen(duped, "r");

	write_constant(helper->in, "capabilities\n");

	while (1) {
	const char capname, arg;
	int mandatory = 0;
	if (recvline(data, &buf))
	exit(128);

	if (!*buf.buf)
	break;

	if (buf.buf == '') {
	capname = buf.buf + 1;
	mandatory = 1;
	} else
	capname = buf.buf;

	if (debug)
	fprintf(stderr, "Debug: Got cap %s\n", capname);
	if (!strcmp(capname, "fetch"))
	data->fetch = 1;
	else if (!strcmp(capname, "option"))
	data->option = 1;
	else if (!strcmp(capname, "push"))
	data->push = 1;
	else if (!strcmp(capname, "import"))
	data->import = 1;
	else if (!strcmp(capname, "bidi-import"))
	data->bidi_import = 1;
	else if (!strcmp(capname, "export"))
	data->export = 1;
	else if (!strcmp(capname, "check-connectivity"))
	data->check_connectivity = 1;
	else if (skip_prefix(capname, "refspec ", &arg)) {
	refspec_append(&data->rs, arg);
	} else if (!strcmp(capname, "connect")) {
	data->connect = 1;
	} else if (!strcmp(capname, "stateless-connect")) {
	data->stateless_connect = 1;
	} else if (!strcmp(capname, "signed-tags")) {
	data->signed_tags = 1;
	} else if (skip_prefix(capname, "export-marks ", &arg)) {
	data->export_marks = xstrdup(arg);
	} else if (skip_prefix(capname, "import-marks ", &arg)) {
	data->import_marks = xstrdup(arg);
	} else if (starts_with(capname, "no-private-update")) {
	data->no_private_update = 1;
	} else if (starts_with(capname, "object-format")) {
	data->object_format = 1;
	} else if (mandatory) {
	die(_("unknown mandatory capability %s; this remote "
	"helper probably needs newer version of Git"),
	capname);
	}
	}
	if (!data->rs.nr && (data->import \|\| data->bidi_import \|\| data->export)) {
	warning(_("this remote helper should implement refspec capability"));
	}
	strbuf_release(&buf);
	if (debug)
	fprintf(stderr, "Debug: Capabilities complete.\n");
	standard_options(transport);
	return data->helper;
	}

	static int disconnect_helper(struct transport *transport)
	{
	struct helper_data *data = transport->data;
	int res = 0;

	if (data->helper) {
	if (debug)
	fprintf(stderr, "Debug: Disconnecting.\n");
	if (!data->no_disconnect_req) {
	/*
	* Ignore write errors; there's nothing we can do,
	* since we're about to close the pipe anyway. And the
	* most likely error is EPIPE due to the helper dying
	* to report an error itself.
	*/
	sigchain_push(SIGPIPE, SIG_IGN);
	xwrite(data->helper->in, "\n", 1);
	sigchain_pop(SIGPIPE);
	}
	close(data->helper->in);
	close(data->helper->out);
	fclose(data->out);
	res = finish_command(data->helper);
	FREE_AND_NULL(data->helper);
	}
	return res;
	}

	static const char *unsupported_options[] = {
	TRANS_OPT_UPLOADPACK,
	TRANS_OPT_RECEIVEPACK,
	TRANS_OPT_THIN,
	TRANS_OPT_KEEP
	};

	static const char *boolean_options[] = {
	TRANS_OPT_THIN,
	TRANS_OPT_KEEP,
	TRANS_OPT_FOLLOWTAGS,
	TRANS_OPT_DEEPEN_RELATIVE
	};

	static int strbuf_set_helper_option(struct helper_data *data,
	struct strbuf *buf)
	{
	int ret;

	sendline(data, buf);
	if (recvline(data, buf))
	exit(128);

	if (!strcmp(buf->buf, "ok"))
	ret = 0;
	else if (starts_with(buf->buf, "error"))
	ret = -1;
	else if (!strcmp(buf->buf, "unsupported"))
	ret = 1;
	else {
	warning(_("%s unexpectedly said: '%s'"), data->name, buf->buf);
	ret = 1;
	}
	return ret;
	}

	static int string_list_set_helper_option(struct helper_data *data,
	const char *name,
	struct string_list *list)
	{
	struct strbuf buf = STRBUF_INIT;
	int i, ret = 0;

	for (i = 0; i < list->nr; i++) {
	strbuf_addf(&buf, "option %s ", name);
	quote_c_style(list->items[i].string, &buf, NULL, 0);
	strbuf_addch(&buf, '\n');

	if ((ret = strbuf_set_helper_option(data, &buf)))
	break;
	strbuf_reset(&buf);
	}
	strbuf_release(&buf);
	return ret;
	}

	static int set_helper_option(struct transport *transport,
	const char name, const char value)
	{
	struct helper_data *data = transport->data;
	struct strbuf buf = STRBUF_INIT;
	int i, ret, is_bool = 0;

	get_helper(transport);

	if (!data->option)
	return 1;

	if (!strcmp(name, "deepen-not"))
	return string_list_set_helper_option(data, name,
	(struct string_list *)value);

	for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
	if (!strcmp(name, unsupported_options[i]))
	return 1;
	}

	for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
	if (!strcmp(name, boolean_options[i])) {
	is_bool = 1;
	break;
	}
	}

	strbuf_addf(&buf, "option %s ", name);
	if (is_bool)
	strbuf_addstr(&buf, value ? "true" : "false");
	else
	quote_c_style(value, &buf, NULL, 0);
	strbuf_addch(&buf, '\n');

	ret = strbuf_set_helper_option(data, &buf);
	strbuf_release(&buf);
	return ret;
	}

	static void standard_options(struct transport *t)
	{
	char buf[16];
	int v = t->verbose;

	set_helper_option(t, "progress", t->progress ? "true" : "false");

	xsnprintf(buf, sizeof(buf), "%d", v + 1);
	set_helper_option(t, "verbosity", buf);

	switch (t->family) {
	case TRANSPORT_FAMILY_ALL:
	/*
	* this is already the default,
	* do not break old remote helpers by setting "all" here
	*/
	break;
	case TRANSPORT_FAMILY_IPV4:
	set_helper_option(t, "family", "ipv4");
	break;
	case TRANSPORT_FAMILY_IPV6:
	set_helper_option(t, "family", "ipv6");
	break;
	}
	}

	static int release_helper(struct transport *transport)
	{
	int res = 0;
	struct helper_data *data = transport->data;
	refspec_clear(&data->rs);
	res = disconnect_helper(transport);
	free(transport->data);
	return res;
	}

	static int fetch_with_fetch(struct transport *transport,
	int nr_heads, struct ref **to_fetch)
	{
	struct helper_data *data = transport->data;
	int i;
	struct strbuf buf = STRBUF_INIT;

	for (i = 0; i < nr_heads; i++) {
	const struct ref *posn = to_fetch[i];
	if (posn->status & REF_STATUS_UPTODATE)
	continue;

	strbuf_addf(&buf, "fetch %s %s\n",
	oid_to_hex(&posn->old_oid),
	posn->symref ? posn->symref : posn->name);
	}

	strbuf_addch(&buf, '\n');
	sendline(data, &buf);

	while (1) {
	const char *name;

	if (recvline(data, &buf))
	exit(128);

	if (skip_prefix(buf.buf, "lock ", &name)) {
	if (transport->pack_lockfiles.nr)
	warning(_("%s also locked %s"), data->name, name);
	else
	string_list_append(&transport->pack_lockfiles,
	name);
	}
	else if (data->check_connectivity &&
	data->transport_options.check_self_contained_and_connected &&
	!strcmp(buf.buf, "connectivity-ok"))
	data->transport_options.self_contained_and_connected = 1;
	else if (!buf.len)
	break;
	else
	warning(_("%s unexpectedly said: '%s'"), data->name, buf.buf);
	}
	strbuf_release(&buf);
	return 0;
	}

	static int get_importer(struct transport transport, struct child_process fastimport)
	{
	struct child_process *helper = get_helper(transport);
	struct helper_data *data = transport->data;
	int cat_blob_fd, code;
	child_process_init(fastimport);
	fastimport->in = xdup(helper->out);
	strvec_push(&fastimport->args, "fast-import");
	strvec_push(&fastimport->args, "--allow-unsafe-features");
	strvec_push(&fastimport->args, debug ? "--stats" : "--quiet");

	if (data->bidi_import) {
	cat_blob_fd = xdup(helper->in);
	strvec_pushf(&fastimport->args, "--cat-blob-fd=%d", cat_blob_fd);
	}
	fastimport->git_cmd = 1;

	code = start_command(fastimport);
	return code;
	}

	static int get_exporter(struct transport *transport,
	struct child_process *fastexport,
	struct string_list *revlist_args)
	{
	struct helper_data *data = transport->data;
	struct child_process *helper = get_helper(transport);
	int i;

	child_process_init(fastexport);

	/* we need to duplicate helper->in because we want to use it after
	* fastexport is done with it. */
	fastexport->out = dup(helper->in);
	strvec_push(&fastexport->args, "fast-export");
	strvec_push(&fastexport->args, "--use-done-feature");
	strvec_push(&fastexport->args, data->signed_tags ?
	"--signed-tags=verbatim" : "--signed-tags=warn-strip");
	if (data->export_marks)
	strvec_pushf(&fastexport->args, "--export-marks=%s.tmp", data->export_marks);
	if (data->import_marks)
	strvec_pushf(&fastexport->args, "--import-marks=%s", data->import_marks);

	for (i = 0; i < revlist_args->nr; i++)
	strvec_push(&fastexport->args, revlist_args->items[i].string);

	fastexport->git_cmd = 1;
	return start_command(fastexport);
	}

	static int fetch_with_import(struct transport *transport,
	int nr_heads, struct ref **to_fetch)
	{
	struct child_process fastimport;
	struct helper_data *data = transport->data;
	int i;
	struct ref *posn;
	struct strbuf buf = STRBUF_INIT;

	get_helper(transport);

	if (get_importer(transport, &fastimport))
	die(_("couldn't run fast-import"));

	for (i = 0; i < nr_heads; i++) {
	posn = to_fetch[i];
	if (posn->status & REF_STATUS_UPTODATE)
	continue;

	strbuf_addf(&buf, "import %s\n",
	posn->symref ? posn->symref : posn->name);
	sendline(data, &buf);
	strbuf_reset(&buf);
	}

	write_constant(data->helper->in, "\n");
	/*
	* remote-helpers that advertise the bidi-import capability are required to
	* buffer the complete batch of import commands until this newline before
	* sending data to fast-import.
	* These helpers read back data from fast-import on their stdin, which could
	* be mixed with import commands, otherwise.
	*/

	if (finish_command(&fastimport))
	die(_("error while running fast-import"));

	/*
	* The fast-import stream of a remote helper that advertises
	* the "refspec" capability writes to the refs named after the
	* right hand side of the first refspec matching each ref we
	* were fetching.
	*
	* (If no "refspec" capability was specified, for historical
	* reasons we default to the equivalent of :.)
	*
	* Store the result in to_fetch[i].old_sha1. Callers such
	* as "git fetch" can use the value to write feedback to the
	* terminal, populate FETCH_HEAD, and determine what new value
	* should be written to peer_ref if the update is a
	* fast-forward or this is a forced update.
	*/
	for (i = 0; i < nr_heads; i++) {
	char private, name;
	posn = to_fetch[i];
	if (posn->status & REF_STATUS_UPTODATE)
	continue;
	name = posn->symref ? posn->symref : posn->name;
	if (data->rs.nr)
	private = apply_refspecs(&data->rs, name);
	else
	private = xstrdup(name);
	if (private) {
	if (read_ref(private, &posn->old_oid) < 0)
	die(_("could not read ref %s"), private);
	free(private);
	}
	}
	strbuf_release(&buf);
	return 0;
	}

	static int run_connect(struct transport transport, struct strbuf cmdbuf)
	{
	struct helper_data *data = transport->data;
	int ret = 0;
	int duped;
	FILE *input;
	struct child_process *helper;

	helper = get_helper(transport);

	/*
	* Yes, dup the pipe another time, as we need unbuffered version
	* of input pipe as FILE*. fclose() closes the underlying fd and
	* stream buffering only can be changed before first I/O operation
	* on it.
	*/
	duped = dup(helper->out);
	if (duped < 0)
	die_errno(_("can't dup helper output fd"));
	input = xfdopen(duped, "r");
	setvbuf(input, NULL, _IONBF, 0);

	sendline(data, cmdbuf);
	if (recvline_fh(input, cmdbuf))
	exit(128);

	if (!strcmp(cmdbuf->buf, "")) {
	data->no_disconnect_req = 1;
	if (debug)
	fprintf(stderr, "Debug: Smart transport connection "
	"ready.\n");
	ret = 1;
	} else if (!strcmp(cmdbuf->buf, "fallback")) {
	if (debug)
	fprintf(stderr, "Debug: Falling back to dumb "
	"transport.\n");
	} else {
	die(_("unknown response to connect: %s"),
	cmdbuf->buf);
	}

	fclose(input);
	return ret;
	}

	static int process_connect_service(struct transport *transport,
	const char name, const char exec)
	{
	struct helper_data *data = transport->data;
	struct strbuf cmdbuf = STRBUF_INIT;
	int ret = 0;

	/*
	* Handle --upload-pack and friends. This is fire and forget...
	* just warn if it fails.
	*/
	if (strcmp(name, exec)) {
	int r = set_helper_option(transport, "servpath", exec);
	if (r > 0)
	warning(_("setting remote service path not supported by protocol"));
	else if (r < 0)
	warning(_("invalid remote service path"));
	}

	if (data->connect) {
	strbuf_addf(&cmdbuf, "connect %s\n", name);
	ret = run_connect(transport, &cmdbuf);
	} else if (data->stateless_connect &&
	(get_protocol_version_config() == protocol_v2) &&
	!strcmp("git-upload-pack", name)) {
	strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
	ret = run_connect(transport, &cmdbuf);
	if (ret)
	transport->stateless_rpc = 1;
	}

	strbuf_release(&cmdbuf);
	return ret;
	}

	static int process_connect(struct transport *transport,
	int for_push)
	{
	struct helper_data *data = transport->data;
	const char *name;
	const char *exec;

	name = for_push ? "git-receive-pack" : "git-upload-pack";
	if (for_push)
	exec = data->transport_options.receivepack;
	else
	exec = data->transport_options.uploadpack;

	return process_connect_service(transport, name, exec);
	}

	static int connect_helper(struct transport transport, const char name,
	const char *exec, int fd[2])
	{
	struct helper_data *data = transport->data;

	/* Get_helper so connect is inited. */
	get_helper(transport);
	if (!data->connect)
	die(_("operation not supported by protocol"));

	if (!process_connect_service(transport, name, exec))
	die(_("can't connect to subservice %s"), name);

	fd[0] = data->helper->out;
	fd[1] = data->helper->in;
	return 0;
	}

	static struct ref get_refs_list_using_list(struct transport transport,
	int for_push);

	static int fetch(struct transport *transport,
	int nr_heads, struct ref **to_fetch)
	{
	struct helper_data *data = transport->data;
	int i, count;

	get_helper(transport);

	if (process_connect(transport, 0)) {
	do_take_over(transport);
	return transport->vtable->fetch(transport, nr_heads, to_fetch);
	}

	/*
	* If we reach here, then the server, the client, and/or the transport
	* helper does not support protocol v2. --negotiate-only requires
	* protocol v2.
	*/
	if (data->transport_options.acked_commits) {
	warning(_("--negotiate-only requires protocol v2"));
	return -1;
	}

	if (!data->get_refs_list_called)
	get_refs_list_using_list(transport, 0);

	count = 0;
	for (i = 0; i < nr_heads; i++)
	if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
	count++;

	if (!count)
	return 0;

	if (data->check_connectivity &&
	data->transport_options.check_self_contained_and_connected)
	set_helper_option(transport, "check-connectivity", "true");

	if (transport->cloning)
	set_helper_option(transport, "cloning", "true");

	if (data->transport_options.update_shallow)
	set_helper_option(transport, "update-shallow", "true");

	if (data->transport_options.filter_options.choice) {
	const char *spec = expand_list_objects_filter_spec(
	&data->transport_options.filter_options);
	set_helper_option(transport, "filter", spec);
	}

	if (data->transport_options.negotiation_tips)
	warning("Ignoring --negotiation-tip because the protocol does not support it.");

	if (data->fetch)
	return fetch_with_fetch(transport, nr_heads, to_fetch);

	if (data->import)
	return fetch_with_import(transport, nr_heads, to_fetch);

	return -1;
	}

	struct push_update_ref_state {
	struct ref *hint;
	struct ref_push_report *report;
	int new_report;
	};

	static int push_update_ref_status(struct strbuf *buf,
	struct push_update_ref_state *state,
	struct ref *remote_refs)
	{
	char refname, msg;
	int status, forced = 0;

	if (starts_with(buf->buf, "option ")) {
	struct object_id old_oid, new_oid;
	const char key, val;
	char *p;

	if (!state->hint \|\| !(state->report \|\| state->new_report))
	die(_("'option' without a matching 'ok/error' directive"));
	if (state->new_report) {
	if (!state->hint->report) {
	CALLOC_ARRAY(state->hint->report, 1);
	state->report = state->hint->report;
	} else {
	state->report = state->hint->report;
	while (state->report->next)
	state->report = state->report->next;
	CALLOC_ARRAY(state->report->next, 1);
	state->report = state->report->next;
	}
	state->new_report = 0;
	}
	key = buf->buf + 7;
	p = strchr(key, ' ');
	if (p)
	*p++ = '\0';
	val = p;
	if (!strcmp(key, "refname"))
	state->report->ref_name = xstrdup_or_null(val);
	else if (!strcmp(key, "old-oid") && val &&
	!parse_oid_hex(val, &old_oid, &val))
	state->report->old_oid = oiddup(&old_oid);
	else if (!strcmp(key, "new-oid") && val &&
	!parse_oid_hex(val, &new_oid, &val))
	state->report->new_oid = oiddup(&new_oid);
	else if (!strcmp(key, "forced-update"))
	state->report->forced_update = 1;
	/* Not update remote namespace again. */
	return 1;
	}

	state->report = NULL;
	state->new_report = 0;

	if (starts_with(buf->buf, "ok ")) {
	status = REF_STATUS_OK;
	refname = buf->buf + 3;
	} else if (starts_with(buf->buf, "error ")) {
	status = REF_STATUS_REMOTE_REJECT;
	refname = buf->buf + 6;
	} else
	die(_("expected ok/error, helper said '%s'"), buf->buf);

	msg = strchr(refname, ' ');
	if (msg) {
	struct strbuf msg_buf = STRBUF_INIT;
	const char *end;

	*msg++ = '\0';
	if (!unquote_c_style(&msg_buf, msg, &end))
	msg = strbuf_detach(&msg_buf, NULL);
	else
	msg = xstrdup(msg);
	strbuf_release(&msg_buf);

	if (!strcmp(msg, "no match")) {
	status = REF_STATUS_NONE;
	FREE_AND_NULL(msg);
	}
	else if (!strcmp(msg, "up to date")) {
	status = REF_STATUS_UPTODATE;
	FREE_AND_NULL(msg);
	}
	else if (!strcmp(msg, "non-fast forward")) {
	status = REF_STATUS_REJECT_NONFASTFORWARD;
	FREE_AND_NULL(msg);
	}
	else if (!strcmp(msg, "already exists")) {
	status = REF_STATUS_REJECT_ALREADY_EXISTS;
	FREE_AND_NULL(msg);
	}
	else if (!strcmp(msg, "fetch first")) {
	status = REF_STATUS_REJECT_FETCH_FIRST;
	FREE_AND_NULL(msg);
	}
	else if (!strcmp(msg, "needs force")) {
	status = REF_STATUS_REJECT_NEEDS_FORCE;
	FREE_AND_NULL(msg);
	}
	else if (!strcmp(msg, "stale info")) {
	status = REF_STATUS_REJECT_STALE;
	FREE_AND_NULL(msg);
	}
	else if (!strcmp(msg, "remote ref updated since checkout")) {
	status = REF_STATUS_REJECT_REMOTE_UPDATED;
	FREE_AND_NULL(msg);
	}
	else if (!strcmp(msg, "forced update")) {
	forced = 1;
	FREE_AND_NULL(msg);
	}
	}

	if (state->hint)
	state->hint = find_ref_by_name(state->hint, refname);
	if (!state->hint)
	state->hint = find_ref_by_name(remote_refs, refname);
	if (!state->hint) {
	warning(_("helper reported unexpected status of %s"), refname);
	return 1;
	}

	if (state->hint->status != REF_STATUS_NONE) {
	/*
	* Earlier, the ref was marked not to be pushed, so ignore the ref
	* status reported by the remote helper if the latter is 'no match'.
	*/
	if (status == REF_STATUS_NONE)
	return 1;
	}

	if (status == REF_STATUS_OK)
	state->new_report = 1;
	state->hint->status = status;
	state->hint->forced_update \|= forced;
	state->hint->remote_status = msg;
	return !(status == REF_STATUS_OK);
	}

	static int push_update_refs_status(struct helper_data *data,
	struct ref *remote_refs,
	int flags)
	{
	struct ref *ref;
	struct ref_push_report *report;
	struct strbuf buf = STRBUF_INIT;
	struct push_update_ref_state state = { remote_refs, NULL, 0 };

	for (;;) {
	if (recvline(data, &buf)) {
	strbuf_release(&buf);
	return 1;
	}
	if (!buf.len)
	break;
	push_update_ref_status(&buf, &state, remote_refs);
	}
	strbuf_release(&buf);

	if (flags & TRANSPORT_PUSH_DRY_RUN \|\| !data->rs.nr \|\| data->no_private_update)
	return 0;

	/* propagate back the update to the remote namespace */
	for (ref = remote_refs; ref; ref = ref->next) {
	char *private;

	if (ref->status != REF_STATUS_OK)
	continue;

	if (!ref->report) {
	private = apply_refspecs(&data->rs, ref->name);
	if (!private)
	continue;
	update_ref("update by helper", private, &(ref->new_oid),
	NULL, 0, 0);
	free(private);
	} else {
	for (report = ref->report; report; report = report->next) {
	private = apply_refspecs(&data->rs,
	report->ref_name
	? report->ref_name
	: ref->name);
	if (!private)
	continue;
	update_ref("update by helper", private,
	report->new_oid
	? report->new_oid
	: &(ref->new_oid),
	NULL, 0, 0);
	free(private);
	}
	}
	}
	return 0;
	}

	static void set_common_push_options(struct transport *transport,
	const char *name, int flags)
	{
	if (flags & TRANSPORT_PUSH_DRY_RUN) {
	if (set_helper_option(transport, "dry-run", "true") != 0)
	die(_("helper %s does not support dry-run"), name);
	} else if (flags & TRANSPORT_PUSH_CERT_ALWAYS) {
	if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
	die(_("helper %s does not support --signed"), name);
	} else if (flags & TRANSPORT_PUSH_CERT_IF_ASKED) {
	if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "if-asked") != 0)
	die(_("helper %s does not support --signed=if-asked"), name);
	}

	if (flags & TRANSPORT_PUSH_ATOMIC)
	if (set_helper_option(transport, TRANS_OPT_ATOMIC, "true") != 0)
	die(_("helper %s does not support --atomic"), name);

	if (flags & TRANSPORT_PUSH_FORCE_IF_INCLUDES)
	if (set_helper_option(transport, TRANS_OPT_FORCE_IF_INCLUDES, "true") != 0)
	die(_("helper %s does not support --%s"),
	name, TRANS_OPT_FORCE_IF_INCLUDES);

	if (flags & TRANSPORT_PUSH_OPTIONS) {
	struct string_list_item *item;
	for_each_string_list_item(item, transport->push_options)
	if (set_helper_option(transport, "push-option", item->string) != 0)
	die(_("helper %s does not support 'push-option'"), name);
	}
	}

	static int push_refs_with_push(struct transport *transport,
	struct ref *remote_refs, int flags)
	{
	int force_all = flags & TRANSPORT_PUSH_FORCE;
	int mirror = flags & TRANSPORT_PUSH_MIRROR;
	int atomic = flags & TRANSPORT_PUSH_ATOMIC;
	struct helper_data *data = transport->data;
	struct strbuf buf = STRBUF_INIT;
	struct ref *ref;
	struct string_list cas_options = STRING_LIST_INIT_DUP;
	struct string_list_item *cas_option;

	get_helper(transport);
	if (!data->push)
	return 1;

	for (ref = remote_refs; ref; ref = ref->next) {
	if (!ref->peer_ref && !mirror)
	continue;

	/* Check for statuses set by set_ref_status_for_push() */
	switch (ref->status) {
	case REF_STATUS_REJECT_NONFASTFORWARD:
	case REF_STATUS_REJECT_STALE:
	case REF_STATUS_REJECT_ALREADY_EXISTS:
	case REF_STATUS_REJECT_REMOTE_UPDATED:
	if (atomic) {
	reject_atomic_push(remote_refs, mirror);
	string_list_clear(&cas_options, 0);
	return 0;
	} else
	continue;
	case REF_STATUS_UPTODATE:
	continue;
	default:
	; /* do nothing */
	}

	if (force_all)
	ref->force = 1;

	strbuf_addstr(&buf, "push ");
	if (!ref->deletion) {
	if (ref->force)
	strbuf_addch(&buf, '+');
	if (ref->peer_ref)
	strbuf_addstr(&buf, ref->peer_ref->name);
	else
	strbuf_addstr(&buf, oid_to_hex(&ref->new_oid));
	}
	strbuf_addch(&buf, ':');
	strbuf_addstr(&buf, ref->name);
	strbuf_addch(&buf, '\n');

	/*
	* The "--force-with-lease" options without explicit
	* values to expect have already been expanded into
	* the ref->old_oid_expect[] field; we can ignore
	* transport->smart_options->cas altogether and instead
	* can enumerate them from the refs.
	*/
	if (ref->expect_old_sha1) {
	struct strbuf cas = STRBUF_INIT;
	strbuf_addf(&cas, "%s:%s",
	ref->name, oid_to_hex(&ref->old_oid_expect));
	string_list_append_nodup(&cas_options,
	strbuf_detach(&cas, NULL));
	}
	}
	if (buf.len == 0) {
	string_list_clear(&cas_options, 0);
	return 0;
	}

	for_each_string_list_item(cas_option, &cas_options)
	set_helper_option(transport, "cas", cas_option->string);
	set_common_push_options(transport, data->name, flags);

	strbuf_addch(&buf, '\n');
	sendline(data, &buf);
	strbuf_release(&buf);
	string_list_clear(&cas_options, 0);

	return push_update_refs_status(data, remote_refs, flags);
	}

	static int push_refs_with_export(struct transport *transport,
	struct ref *remote_refs, int flags)
	{
	struct ref *ref;
	struct child_process *helper, exporter;
	struct helper_data *data = transport->data;
	struct string_list revlist_args = STRING_LIST_INIT_DUP;
	struct strbuf buf = STRBUF_INIT;

	if (!data->rs.nr)
	die(_("remote-helper doesn't support push; refspec needed"));

	set_common_push_options(transport, data->name, flags);
	if (flags & TRANSPORT_PUSH_FORCE) {
	if (set_helper_option(transport, "force", "true") != 0)
	warning(_("helper %s does not support 'force'"), data->name);
	}

	helper = get_helper(transport);

	write_constant(helper->in, "export\n");

	for (ref = remote_refs; ref; ref = ref->next) {
	char *private;
	struct object_id oid;

	private = apply_refspecs(&data->rs, ref->name);
	if (private && !get_oid(private, &oid)) {
	strbuf_addf(&buf, "^%s", private);
	string_list_append_nodup(&revlist_args,
	strbuf_detach(&buf, NULL));
	oidcpy(&ref->old_oid, &oid);
	}
	free(private);

	if (ref->peer_ref) {
	if (strcmp(ref->name, ref->peer_ref->name)) {
	if (!ref->deletion) {
	const char *name;
	int flag;

	/* Follow symbolic refs (mainly for HEAD). */
	name = resolve_ref_unsafe(ref->peer_ref->name,
	RESOLVE_REF_READING,
	&oid, &flag);
	if (!name \|\| !(flag & REF_ISSYMREF))
	name = ref->peer_ref->name;

	strbuf_addf(&buf, "%s:%s", name, ref->name);
	} else
	strbuf_addf(&buf, ":%s", ref->name);

	string_list_append(&revlist_args, "--refspec");
	string_list_append(&revlist_args, buf.buf);
	strbuf_release(&buf);
	}
	if (!ref->deletion)
	string_list_append(&revlist_args, ref->peer_ref->name);
	}
	}

	if (get_exporter(transport, &exporter, &revlist_args))
	die(_("couldn't run fast-export"));

	string_list_clear(&revlist_args, 1);

	if (finish_command(&exporter))
	die(_("error while running fast-export"));
	if (push_update_refs_status(data, remote_refs, flags))
	return 1;

	if (data->export_marks) {
	strbuf_addf(&buf, "%s.tmp", data->export_marks);
	rename(buf.buf, data->export_marks);
	strbuf_release(&buf);
	}

	return 0;
	}

	static int push_refs(struct transport *transport,
	struct ref *remote_refs, int flags)
	{
	struct helper_data *data = transport->data;

	if (process_connect(transport, 1)) {
	do_take_over(transport);
	return transport->vtable->push_refs(transport, remote_refs, flags);
	}

	if (!remote_refs) {
	fprintf(stderr,
	_("No refs in common and none specified; doing nothing.\n"
	"Perhaps you should specify a branch.\n"));
	return 0;
	}

	if (data->push)
	return push_refs_with_push(transport, remote_refs, flags);

	if (data->export)
	return push_refs_with_export(transport, remote_refs, flags);

	return -1;
	}


	static int has_attribute(const char attrs, const char attr)
	{
	int len;
	if (!attrs)
	return 0;

	len = strlen(attr);
	for (;;) {
	const char *space = strchrnul(attrs, ' ');
	if (len == space - attrs && !strncmp(attrs, attr, len))
	return 1;
	if (!*space)
	return 0;
	attrs = space + 1;
	}
	}

	static struct ref get_refs_list(struct transport transport, int for_push,
	struct transport_ls_refs_options *transport_options)
	{
	get_helper(transport);

	if (process_connect(transport, for_push)) {
	do_take_over(transport);
	return transport->vtable->get_refs_list(transport, for_push,
	transport_options);
	}

	return get_refs_list_using_list(transport, for_push);
	}

	static struct ref get_refs_list_using_list(struct transport transport,
	int for_push)
	{
	struct helper_data *data = transport->data;
	struct child_process *helper;
	struct ref *ret = NULL;
	struct ref **tail = &ret;
	struct ref *posn;
	struct strbuf buf = STRBUF_INIT;

	data->get_refs_list_called = 1;
	helper = get_helper(transport);

	if (data->object_format) {
	write_str_in_full(helper->in, "option object-format\n");
	if (recvline(data, &buf) \|\| strcmp(buf.buf, "ok"))
	exit(128);
	}

	if (data->push && for_push)
	write_str_in_full(helper->in, "list for-push\n");
	else
	write_str_in_full(helper->in, "list\n");

	while (1) {
	char eov, eon;
	if (recvline(data, &buf))
	exit(128);

	if (!*buf.buf)
	break;
	else if (buf.buf[0] == ':') {
	const char *value;
	if (skip_prefix(buf.buf, ":object-format ", &value)) {
	int algo = hash_algo_by_name(value);
	if (algo == GIT_HASH_UNKNOWN)
	die(_("unsupported object format '%s'"),
	value);
	transport->hash_algo = &hash_algos[algo];
	}
	continue;
	}

	eov = strchr(buf.buf, ' ');
	if (!eov)
	die(_("malformed response in ref list: %s"), buf.buf);
	eon = strchr(eov + 1, ' ');
	*eov = '\0';
	if (eon)
	*eon = '\0';
	*tail = alloc_ref(eov + 1);
	if (buf.buf[0] == '@')
	(*tail)->symref = xstrdup(buf.buf + 1);
	else if (buf.buf[0] != '?')
	get_oid_hex_algop(buf.buf, &(*tail)->old_oid, transport->hash_algo);
	if (eon) {
	if (has_attribute(eon + 1, "unchanged")) {
	(*tail)->status \|= REF_STATUS_UPTODATE;
	if (read_ref((tail)->name, &(tail)->old_oid) < 0)
	die(_("could not read ref %s"),
	(*tail)->name);
	}
	}
	tail = &((*tail)->next);
	}
	if (debug)
	fprintf(stderr, "Debug: Read ref listing.\n");
	strbuf_release(&buf);

	for (posn = ret; posn; posn = posn->next)
	resolve_remote_symref(posn, ret);

	return ret;
	}

	static struct transport_vtable vtable = {
	set_helper_option,
	get_refs_list,
	fetch,
	push_refs,
	connect_helper,
	release_helper
	};

	int transport_helper_init(struct transport transport, const char name)
	{
	struct helper_data data = xcalloc(1, sizeof(data));
	data->name = name;

	transport_check_allowed(name);

	if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
	debug = 1;

	transport->data = data;
	transport->vtable = &vtable;
	transport->smart_options = &(data->transport_options);
	return 0;
	}

	/*
	* Linux pipes can buffer 65536 bytes at once (and most platforms can
	* buffer less), so attempt reads and writes with up to that size.
	*/
	#define BUFFERSIZE 65536
	/* This should be enough to hold debugging message. */
	#define PBUFFERSIZE 8192

	/* Print bidirectional transfer loop debug message. */
	__attribute__((format (printf, 1, 2)))
	static void transfer_debug(const char *fmt, ...)
	{
	/*
	* NEEDSWORK: This function is sometimes used from multiple threads, and
	* we end up using debug_enabled racily. That "should not matter" since
	* we always write the same value, but it's still wrong. This function
	* is listed in .tsan-suppressions for the time being.
	*/

	va_list args;
	char msgbuf[PBUFFERSIZE];
	static int debug_enabled = -1;

	if (debug_enabled < 0)
	debug_enabled = getenv("GIT_TRANSLOOP_DEBUG") ? 1 : 0;
	if (!debug_enabled)
	return;

	va_start(args, fmt);
	vsnprintf(msgbuf, PBUFFERSIZE, fmt, args);
	va_end(args);
	fprintf(stderr, "Transfer loop debugging: %s\n", msgbuf);
	}

	/* Stream state: More data may be coming in this direction. */
	#define SSTATE_TRANSFERRING 0
	/*
	* Stream state: No more data coming in this direction, flushing rest of
	* data.
	*/
	#define SSTATE_FLUSHING 1
	/* Stream state: Transfer in this direction finished. */
	#define SSTATE_FINISHED 2

	#define STATE_NEEDS_READING(state) ((state) <= SSTATE_TRANSFERRING)
	#define STATE_NEEDS_WRITING(state) ((state) <= SSTATE_FLUSHING)
	#define STATE_NEEDS_CLOSING(state) ((state) == SSTATE_FLUSHING)

	/* Unidirectional transfer. */
	struct unidirectional_transfer {
	/* Source */
	int src;
	/* Destination */
	int dest;
	/* Is source socket? */
	int src_is_sock;
	/* Is destination socket? */
	int dest_is_sock;
	/* Transfer state (TRANSFERRING/FLUSHING/FINISHED) */
	int state;
	/* Buffer. */
	char buf[BUFFERSIZE];
	/* Buffer used. */
	size_t bufuse;
	/* Name of source. */
	const char *src_name;
	/* Name of destination. */
	const char *dest_name;
	};

	/* Closes the target (for writing) if transfer has finished. */
	static void udt_close_if_finished(struct unidirectional_transfer *t)
	{
	if (STATE_NEEDS_CLOSING(t->state) && !t->bufuse) {
	t->state = SSTATE_FINISHED;
	if (t->dest_is_sock)
	shutdown(t->dest, SHUT_WR);
	else
	close(t->dest);
	transfer_debug("Closed %s.", t->dest_name);
	}
	}

	/*
	* Tries to read data from source into buffer. If buffer is full,
	* no data is read. Returns 0 on success, -1 on error.
	*/
	static int udt_do_read(struct unidirectional_transfer *t)
	{
	ssize_t bytes;

	if (t->bufuse == BUFFERSIZE)
	return 0; /* No space for more. */

	transfer_debug("%s is readable", t->src_name);
	bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
	if (bytes < 0) {
	error_errno(_("read(%s) failed"), t->src_name);
	return -1;
	} else if (bytes == 0) {
	transfer_debug("%s EOF (with %i bytes in buffer)",
	t->src_name, (int)t->bufuse);
	t->state = SSTATE_FLUSHING;
	} else if (bytes > 0) {
	t->bufuse += bytes;
	transfer_debug("Read %i bytes from %s (buffer now at %i)",
	(int)bytes, t->src_name, (int)t->bufuse);
	}
	return 0;
	}

	/* Tries to write data from buffer into destination. If buffer is empty,
	* no data is written. Returns 0 on success, -1 on error.
	*/
	static int udt_do_write(struct unidirectional_transfer *t)
	{
	ssize_t bytes;

	if (t->bufuse == 0)
	return 0; /* Nothing to write. */

	transfer_debug("%s is writable", t->dest_name);
	bytes = xwrite(t->dest, t->buf, t->bufuse);
	if (bytes < 0) {
	error_errno(_("write(%s) failed"), t->dest_name);
	return -1;
	} else if (bytes > 0) {
	t->bufuse -= bytes;
	if (t->bufuse)
	memmove(t->buf, t->buf + bytes, t->bufuse);
	transfer_debug("Wrote %i bytes to %s (buffer now at %i)",
	(int)bytes, t->dest_name, (int)t->bufuse);
	}
	return 0;
	}


	/* State of bidirectional transfer loop. */
	struct bidirectional_transfer_state {
	/* Direction from program to git. */
	struct unidirectional_transfer ptg;
	/* Direction from git to program. */
	struct unidirectional_transfer gtp;
	};

	static void udt_copy_task_routine(void udt)
	{
	struct unidirectional_transfer t = (struct unidirectional_transfer )udt;
	while (t->state != SSTATE_FINISHED) {
	if (STATE_NEEDS_READING(t->state))
	if (udt_do_read(t))
	return NULL;
	if (STATE_NEEDS_WRITING(t->state))
	if (udt_do_write(t))
	return NULL;
	if (STATE_NEEDS_CLOSING(t->state))
	udt_close_if_finished(t);
	}
	return udt; /* Just some non-NULL value. */
	}

	#ifndef NO_PTHREADS

	/*
	* Join thread, with appropriate errors on failure. Name is name for the
	* thread (for error messages). Returns 0 on success, 1 on failure.
	*/
	static int tloop_join(pthread_t thread, const char *name)
	{
	int err;
	void *tret;
	err = pthread_join(thread, &tret);
	if (!tret) {
	error(_("%s thread failed"), name);
	return 1;
	}
	if (err) {
	error(_("%s thread failed to join: %s"), name, strerror(err));
	return 1;
	}
	return 0;
	}

	/*
	* Spawn the transfer tasks and then wait for them. Returns 0 on success,
	* -1 on failure.
	*/
	static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
	{
	pthread_t gtp_thread;
	pthread_t ptg_thread;
	int err;
	int ret = 0;
	err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
	&s->gtp);
	if (err)
	die(_("can't start thread for copying data: %s"), strerror(err));
	err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
	&s->ptg);
	if (err)
	die(_("can't start thread for copying data: %s"), strerror(err));

	ret \|= tloop_join(gtp_thread, "Git to program copy");
	ret \|= tloop_join(ptg_thread, "Program to git copy");
	return ret;
	}
	#else

	/* Close the source and target (for writing) for transfer. */
	static void udt_kill_transfer(struct unidirectional_transfer *t)
	{
	t->state = SSTATE_FINISHED;
	/*
	* Socket read end left open isn't a disaster if nobody
	* attempts to read from it (mingw compat headers do not
	* have SHUT_RD)...
	*
	* We can't fully close the socket since otherwise gtp
	* task would first close the socket it sends data to
	* while closing the ptg file descriptors.
	*/
	if (!t->src_is_sock)
	close(t->src);
	if (t->dest_is_sock)
	shutdown(t->dest, SHUT_WR);
	else
	close(t->dest);
	}

	/*
	* Join process, with appropriate errors on failure. Name is name for the
	* process (for error messages). Returns 0 on success, 1 on failure.
	*/
	static int tloop_join(pid_t pid, const char *name)
	{
	int tret;
	if (waitpid(pid, &tret, 0) < 0) {
	error_errno(_("%s process failed to wait"), name);
	return 1;
	}
	if (!WIFEXITED(tret) \|\| WEXITSTATUS(tret)) {
	error(_("%s process failed"), name);
	return 1;
	}
	return 0;
	}

	/*
	* Spawn the transfer tasks and then wait for them. Returns 0 on success,
	* -1 on failure.
	*/
	static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
	{
	pid_t pid1, pid2;
	int ret = 0;

	/* Fork thread #1: git to program. */
	pid1 = fork();
	if (pid1 < 0)
	die_errno(_("can't start thread for copying data"));
	else if (pid1 == 0) {
	udt_kill_transfer(&s->ptg);
	exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
	}

	/* Fork thread #2: program to git. */
	pid2 = fork();
	if (pid2 < 0)
	die_errno(_("can't start thread for copying data"));
	else if (pid2 == 0) {
	udt_kill_transfer(&s->gtp);
	exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);
	}

	/*
	* Close both streams in parent as to not interfere with
	* end of file detection and wait for both tasks to finish.
	*/
	udt_kill_transfer(&s->gtp);
	udt_kill_transfer(&s->ptg);
	ret \|= tloop_join(pid1, "Git to program copy");
	ret \|= tloop_join(pid2, "Program to git copy");
	return ret;
	}
	#endif

	/*
	* Copies data from stdin to output and from input to stdout simultaneously.
	* Additionally filtering through given filter. If filter is NULL, uses
	* identity filter.
	*/
	int bidirectional_transfer_loop(int input, int output)
	{
	struct bidirectional_transfer_state state;

	/* Fill the state fields. */
	state.ptg.src = input;
	state.ptg.dest = 1;
	state.ptg.src_is_sock = (input == output);
	state.ptg.dest_is_sock = 0;
	state.ptg.state = SSTATE_TRANSFERRING;
	state.ptg.bufuse = 0;
	state.ptg.src_name = "remote input";
	state.ptg.dest_name = "stdout";

	state.gtp.src = 0;
	state.gtp.dest = output;
	state.gtp.src_is_sock = 0;
	state.gtp.dest_is_sock = (input == output);
	state.gtp.state = SSTATE_TRANSFERRING;
	state.gtp.bufuse = 0;
	state.gtp.src_name = "stdin";
	state.gtp.dest_name = "remote output";

	return tloop_spawnwait_tasks(&state);
	}

	void reject_atomic_push(struct ref *remote_refs, int mirror_mode)
	{
	struct ref *ref;

	/* Mark other refs as failed */
	for (ref = remote_refs; ref; ref = ref->next) {
	if (!ref->peer_ref && !mirror_mode)
	continue;

	switch (ref->status) {
	case REF_STATUS_NONE:
	case REF_STATUS_OK:
	case REF_STATUS_EXPECTING_REPORT:
	ref->status = REF_STATUS_ATOMIC_PUSH_FAILED;
	continue;
	default:
	break; /* do nothing */
	}
	}
	return;
	}

Jul	AUG	Apr
	14
2017	2021	2023

git / git

git/transport-helper.c