/*

 * Copyright (C) the libgit2 contributors. All rights reserved.

 *

 * This file is part of libgit2, distributed under the GNU GPL v2 with

 * a Linking Exception. For full terms see the included COPYING file.

 */

#include "git2.h"

#include "smart.h"

#include "refs.h"

#include "refspec.h"

#include "proxy.h"

static int git_smart__recv_cb(gitno_buffer *buf)

{

	transport_smart *t = (transport_smart *) buf->cb_data;

	size_t old_len, bytes_read;

	int error;

	assert(t->current_stream);

	old_len = buf->offset;

	if ((error = t->current_stream->read(t->current_stream, buf->data + buf->offset, buf->len - buf->offset, &bytes_read)) < 0)

		return error;

	buf->offset += bytes_read;

	if (t->packetsize_cb && !t->cancelled.val) {

		error = t->packetsize_cb(bytes_read, t->packetsize_payload);

		if (error) {

			git_atomic_set(&t->cancelled, 1);

			return GIT_EUSER;

		}

	}

	return (int)(buf->offset - old_len);

}

GIT_INLINE(int) git_smart__reset_stream(transport_smart *t, bool close_subtransport)

{

	if (t->current_stream) {

		t->current_stream->free(t->current_stream);

		t->current_stream = NULL;

	}

	if (t->url) {

		git__free(t->url);

		t->url = NULL;

	}

	if (close_subtransport &&

		t->wrapped->close(t->wrapped) < 0)

		return -1;

	return 0;

}

static int git_smart__set_callbacks(

	git_transport *transport,

	git_transport_message_cb progress_cb,

	git_transport_message_cb error_cb,

	git_transport_certificate_check_cb certificate_check_cb,

	void *message_cb_payload)

{

	transport_smart *t = (transport_smart *)transport;

	t->progress_cb = progress_cb;

	t->error_cb = error_cb;

	t->certificate_check_cb = certificate_check_cb;

	t->message_cb_payload = message_cb_payload;

	return 0;

}

static int http_header_name_length(const char *http_header)

{

	const char *colon = strchr(http_header, ':');

	if (!colon)

		return 0;

	return colon - http_header;

}

static bool is_malformed_http_header(const char *http_header)

{

	const char *c;

	int name_len;

	// Disallow \r and \n

	c = strchr(http_header, '\r');

	if (c)

		return true;

	c = strchr(http_header, '\n');

	if (c)

		return true;

	// Require a header name followed by :

	name_len = http_header_name_length(http_header);

	if (name_len < 1)

		return true;

	return false;

}

static char *forbidden_custom_headers[] = {

	"User-Agent",

	"Host",

	"Accept",

	"Content-Type",

	"Transfer-Encoding",

	"Content-Length",

};

static bool is_forbidden_custom_header(const char *custom_header)

{

	unsigned long i;

	int name_len = http_header_name_length(custom_header);

	// Disallow headers that we set

	for (i = 0; i < ARRAY_SIZE(forbidden_custom_headers); i++)

		if (strncmp(forbidden_custom_headers[i], custom_header, name_len) == 0)

			return true;

	return false;

}

static int git_smart__set_custom_headers(

	git_transport *transport,

	const git_strarray *custom_headers)

{

	transport_smart *t = (transport_smart *)transport;

	size_t i;

	if (t->custom_headers.count)

		git_strarray_free(&t->custom_headers);

	if (!custom_headers)

		return 0;

	for (i = 0; i < custom_headers->count; i++) {

		if (is_malformed_http_header(custom_headers->strings[i])) {

			giterr_set(GITERR_INVALID, "custom HTTP header '%s' is malformed", custom_headers->strings[i]);

			return -1;

		}

		if (is_forbidden_custom_header(custom_headers->strings[i])) {

			giterr_set(GITERR_INVALID, "custom HTTP header '%s' is already set by libgit2", custom_headers->strings[i]);

			return -1;

		}

	}

	return git_strarray_copy(&t->custom_headers, custom_headers);

}

int git_smart__update_heads(transport_smart *t, git_vector *symrefs)

{

	size_t i;

	git_pkt *pkt;

	git_vector_clear(&t->heads);

	git_vector_foreach(&t->refs, i, pkt) {

		git_pkt_ref *ref = (git_pkt_ref *) pkt;

		if (pkt->type != GIT_PKT_REF)

			continue;

		if (symrefs) {

			git_refspec *spec;

			git_buf buf = GIT_BUF_INIT;

			size_t j;

			int error = 0;

			git_vector_foreach(symrefs, j, spec) {

				git_buf_clear(&buf;;

				if (git_refspec_src_matches(spec, ref->head.name) &&

				    !(error = git_refspec_transform(&buf, spec, ref->head.name)))

					ref->head.symref_target = git_buf_detach(&buf;;

			}

			git_buf_free(&buf;;

			if (error < 0)

				return error;

		}

		if (git_vector_insert(&t->heads, &ref->head) < 0)

			return -1;

	}

	return 0;

}

static void free_symrefs(git_vector *symrefs)

{

	git_refspec *spec;

	size_t i;

	git_vector_foreach(symrefs, i, spec) {

		git_refspec__free(spec);

		git__free(spec);

	}

	git_vector_free(symrefs);

}

static int git_smart__connect(

	git_transport *transport,

	const char *url,

	git_cred_acquire_cb cred_acquire_cb,

	void *cred_acquire_payload,

	const git_proxy_options *proxy,

	int direction,

	int flags)

{

	transport_smart *t = (transport_smart *)transport;

	git_smart_subtransport_stream *stream;

	int error;

	git_pkt *pkt;

	git_pkt_ref *first;

	git_vector symrefs;

	git_smart_service_t service;

	if (git_smart__reset_stream(t, true) < 0)

		return -1;

	t->url = git__strdup(url);

	GITERR_CHECK_ALLOC(t->url);

	if (git_proxy_options_dup(&t->proxy, proxy) < 0)

		return -1;

	t->direction = direction;

	t->flags = flags;

	t->cred_acquire_cb = cred_acquire_cb;

	t->cred_acquire_payload = cred_acquire_payload;

	if (GIT_DIRECTION_FETCH == t->direction)

		service = GIT_SERVICE_UPLOADPACK_LS;

	else if (GIT_DIRECTION_PUSH == t->direction)

		service = GIT_SERVICE_RECEIVEPACK_LS;

	else {

		giterr_set(GITERR_NET, "invalid direction");

		return -1;

	}

	if ((error = t->wrapped->action(&stream, t->wrapped, t->url, service)) < 0)

		return error;

	/* Save off the current stream (i.e. socket) that we are working with */

	t->current_stream = stream;

	gitno_buffer_setup_callback(&t->buffer, t->buffer_data, sizeof(t->buffer_data), git_smart__recv_cb, t);

	/* 2 flushes for RPC; 1 for stateful */

	if ((error = git_smart__store_refs(t, t->rpc ? 2 : 1)) < 0)

		return error;

	/* Strip the comment packet for RPC */

	if (t->rpc) {

		pkt = (git_pkt *)git_vector_get(&t->refs, 0);

		if (!pkt || GIT_PKT_COMMENT != pkt->type) {

			giterr_set(GITERR_NET, "invalid response");

			return -1;

		} else {

			/* Remove the comment pkt from the list */

			git_vector_remove(&t->refs, 0);

			git__free(pkt);

		}

	}

	/* We now have loaded the refs. */

	t->have_refs = 1;

	first = (git_pkt_ref *)git_vector_get(&t->refs, 0);

	if ((error = git_vector_init(&symrefs, 1, NULL)) < 0)

		return error;

	/* Detect capabilities */

	if (git_smart__detect_caps(first, &t->caps, &symrefs) < 0)

		return -1;

	/* If the only ref in the list is capabilities^{} with OID_ZERO, remove it */

	if (1 == t->refs.length && !strcmp(first->head.name, "capabilities^{}") &&

		git_oid_iszero(&first->head.oid)) {

		git_vector_clear(&t->refs);

		git_pkt_free((git_pkt *)first);

	}

	/* Keep a list of heads for _ls */

	git_smart__update_heads(t, &symrefs);

	free_symrefs(&symrefs);

	if (t->rpc && git_smart__reset_stream(t, false) < 0)

		return -1;

	/* We're now logically connected. */

	t->connected = 1;

	return 0;

}

static int git_smart__ls(const git_remote_head ***out, size_t *size, git_transport *transport)

{

	transport_smart *t = (transport_smart *)transport;

	if (!t->have_refs) {

		giterr_set(GITERR_NET, "the transport has not yet loaded the refs");

		return -1;

	}

	*out = (const git_remote_head **) t->heads.contents;

	*size = t->heads.length;

	return 0;

}

int git_smart__negotiation_step(git_transport *transport, void *data, size_t len)

{

	transport_smart *t = (transport_smart *)transport;

	git_smart_subtransport_stream *stream;

	int error;

	if (t->rpc && git_smart__reset_stream(t, false) < 0)

		return -1;

	if (GIT_DIRECTION_FETCH != t->direction) {

		giterr_set(GITERR_NET, "this operation is only valid for fetch");

		return -1;

	}

	if ((error = t->wrapped->action(&stream, t->wrapped, t->url, GIT_SERVICE_UPLOADPACK)) < 0)

		return error;

	/* If this is a stateful implementation, the stream we get back should be the same */

	assert(t->rpc || t->current_stream == stream);

	/* Save off the current stream (i.e. socket) that we are working with */

	t->current_stream = stream;

	if ((error = stream->write(stream, (const char *)data, len)) < 0)

		return error;

	gitno_buffer_setup_callback(&t->buffer, t->buffer_data, sizeof(t->buffer_data), git_smart__recv_cb, t);

	return 0;

}

int git_smart__get_push_stream(transport_smart *t, git_smart_subtransport_stream **stream)

{

	int error;

	if (t->rpc && git_smart__reset_stream(t, false) < 0)

		return -1;

	if (GIT_DIRECTION_PUSH != t->direction) {

		giterr_set(GITERR_NET, "this operation is only valid for push");

		return -1;

	}

	if ((error = t->wrapped->action(stream, t->wrapped, t->url, GIT_SERVICE_RECEIVEPACK)) < 0)

		return error;

	/* If this is a stateful implementation, the stream we get back should be the same */

	assert(t->rpc || t->current_stream == *stream);

	/* Save off the current stream (i.e. socket) that we are working with */

	t->current_stream = *stream;

	gitno_buffer_setup_callback(&t->buffer, t->buffer_data, sizeof(t->buffer_data), git_smart__recv_cb, t);

	return 0;

}

static void git_smart__cancel(git_transport *transport)

{

	transport_smart *t = (transport_smart *)transport;

	git_atomic_set(&t->cancelled, 1);

}

static int git_smart__is_connected(git_transport *transport)

{

	transport_smart *t = (transport_smart *)transport;

	return t->connected;

}

static int git_smart__read_flags(git_transport *transport, int *flags)

{

	transport_smart *t = (transport_smart *)transport;

	*flags = t->flags;

	return 0;

}

static int git_smart__close(git_transport *transport)

{

	transport_smart *t = (transport_smart *)transport;

	git_vector *common = &t->common;

	unsigned int i;

	git_pkt *p;

	int ret;

	git_smart_subtransport_stream *stream;

	const char flush[] = "0000";

	/*

	 * If we're still connected at this point and not using RPC,

	 * we should say goodbye by sending a flush, or git-daemon

	 * will complain that we disconnected unexpectedly.

	 */

	if (t->connected && !t->rpc &&

	    !t->wrapped->action(&stream, t->wrapped, t->url, GIT_SERVICE_UPLOADPACK)) {

		t->current_stream->write(t->current_stream, flush, 4);

	}

	ret = git_smart__reset_stream(t, true);

	git_vector_foreach(common, i, p)

		git_pkt_free(p);

	git_vector_free(common);

	if (t->url) {

		git__free(t->url);

		t->url = NULL;

	}

	t->connected = 0;

	return ret;

}

static void git_smart__free(git_transport *transport)

{

	transport_smart *t = (transport_smart *)transport;

	git_vector *refs = &t->refs;

	unsigned int i;

	git_pkt *p;

	/* Make sure that the current stream is closed, if we have one. */

	git_smart__close(transport);

	/* Free the subtransport */

	t->wrapped->free(t->wrapped);

	git_vector_free(&t->heads);

	git_vector_foreach(refs, i, p)

		git_pkt_free(p);

	git_vector_free(refs);

	git__free((char *)t->proxy.url);

	git_strarray_free(&t->custom_headers);

	git__free(t);

}

static int ref_name_cmp(const void *a, const void *b)

{

	const git_pkt_ref *ref_a = a, *ref_b = b;

	return strcmp(ref_a->head.name, ref_b->head.name);

}

int git_transport_smart_certificate_check(git_transport *transport, git_cert *cert, int valid, const char *hostname)

{

	transport_smart *t = (transport_smart *)transport;

	return t->certificate_check_cb(cert, valid, hostname, t->message_cb_payload);

}

int git_transport_smart_credentials(git_cred **out, git_transport *transport, const char *user, int methods)

{

	transport_smart *t = (transport_smart *)transport;

	return t->cred_acquire_cb(out, t->url, user, methods, t->cred_acquire_payload);

}

int git_transport_smart_proxy_options(git_proxy_options *out, git_transport *transport)

{

	transport_smart *t = (transport_smart *) transport;

	return git_proxy_options_dup(out, &t->proxy);

}

int git_transport_smart(git_transport **out, git_remote *owner, void *param)

{

	transport_smart *t;

	git_smart_subtransport_definition *definition = (git_smart_subtransport_definition *)param;

	if (!param)

		return -1;

	t = git__calloc(1, sizeof(transport_smart));

	GITERR_CHECK_ALLOC(t);

	t->parent.version = GIT_TRANSPORT_VERSION;

	t->parent.set_callbacks = git_smart__set_callbacks;

	t->parent.set_custom_headers = git_smart__set_custom_headers;

	t->parent.connect = git_smart__connect;

	t->parent.close = git_smart__close;

	t->parent.free = git_smart__free;

	t->parent.negotiate_fetch = git_smart__negotiate_fetch;

	t->parent.download_pack = git_smart__download_pack;

	t->parent.push = git_smart__push;

	t->parent.ls = git_smart__ls;

	t->parent.is_connected = git_smart__is_connected;

	t->parent.read_flags = git_smart__read_flags;

	t->parent.cancel = git_smart__cancel;

	t->owner = owner;

	t->rpc = definition->rpc;

	if (git_vector_init(&t->refs, 16, ref_name_cmp) < 0) {

		git__free(t);

		return -1;

	}

	if (git_vector_init(&t->heads, 16, ref_name_cmp) < 0) {

		git__free(t);

		return -1;

	}

	if (definition->callback(&t->wrapped, &t->parent, definition->param) < 0) {

		git__free(t);

		return -1;

	}

	*out = (git_transport *) t;

	return 0;

}