pipewire/pipewire/modules/module-protocol-native.c

/* PipeWire
 * Copyright (C) 2015 Wim Taymans <wim.taymans@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/file.h>

#include "config.h"

#include "pipewire/client/pipewire.h"
#include "pipewire/client/log.h"
#include "pipewire/client/interfaces.h"

#include "pipewire/server/core.h"
#include "pipewire/server/protocol-native.h"
#include "pipewire/server/node.h"
#include "pipewire/server/module.h"
#include "pipewire/server/client-node.h"
#include "pipewire/server/client.h"
#include "pipewire/server/resource.h"
#include "pipewire/server/link.h"
#include "pipewire/server/node-factory.h"
#include "pipewire/server/data-loop.h"
#include "pipewire/server/main-loop.h"

#ifndef UNIX_PATH_MAX
#define UNIX_PATH_MAX   108
#endif

#define LOCK_SUFFIX     ".lock"
#define LOCK_SUFFIXLEN  5

typedef bool(*demarshal_func_t) (void *object, void *data, size_t size);

struct socket {
	int fd;
	int fd_lock;
	struct sockaddr_un addr;
	char lock_addr[UNIX_PATH_MAX + LOCK_SUFFIXLEN];

	struct pw_loop *loop;
	struct spa_source *source;
	char *core_name;
	struct spa_list link;
};

struct impl {
	struct pw_core *core;
	struct spa_list link;

	struct pw_properties *properties;

	struct spa_list socket_list;
	struct spa_list client_list;

	struct pw_listener before_iterate;
};

struct native_client {
	struct impl *impl;
	struct spa_list link;
	struct pw_client *client;
	int fd;
	struct spa_source *source;
	struct pw_connection *connection;
	struct pw_listener resource_added;
	struct pw_listener busy_changed;
};

static void client_destroy(struct native_client *this)
{
	pw_loop_destroy_source(this->impl->core->main_loop->loop, this->source);
	pw_client_destroy(this->client);
	spa_list_remove(&this->link);

	pw_connection_destroy(this->connection);
	close(this->fd);
	free(this);
}

static void
process_messages(struct native_client *client)
{
	struct pw_connection *conn = client->connection;
	uint8_t opcode;
	uint32_t id;
	uint32_t size;
	struct pw_client *c = client->client;
	void *message;

	while (pw_connection_get_next(conn, &opcode, &id, &message, &size)) {
		struct pw_resource *resource;
		const demarshal_func_t *demarshal;

		pw_log_trace("protocol-native %p: got message %d from %u", client->impl,
			     opcode, id);

		resource = pw_map_lookup(&c->objects, id);
		if (resource == NULL) {
			pw_log_error("protocol-native %p: unknown resource %u",
				     client->impl, id);
			continue;
		}
		if (opcode >= resource->iface->n_methods) {
			pw_log_error("protocol-native %p: invalid method %u %u", client->impl,
				     id,  opcode);
			client_destroy(client);
			break;
		}
		demarshal = resource->iface->methods;
		if (!demarshal[opcode] || !demarshal[opcode] (resource, message, size)) {
			pw_log_error("protocol-native %p: invalid message received %u %u",
				     client->impl, id, opcode);
			client_destroy(client);
			break;
		}
		if (c->busy) {
			break;
		}
	}
}

static void
on_resource_added(struct pw_listener *listener,
		  struct pw_client *client, struct pw_resource *resource)
{
	pw_protocol_native_server_setup(resource);
}

static void
on_busy_changed(struct pw_listener *listener,
		struct pw_client *client)
{
	struct native_client *c = SPA_CONTAINER_OF(listener, struct native_client, busy_changed);
	enum spa_io mask = SPA_IO_ERR | SPA_IO_HUP;

	if (!client->busy)
		mask |= SPA_IO_IN;

	pw_loop_update_io(c->impl->core->main_loop->loop, c->source, mask);

	if (!client->busy)
		process_messages(c);

}

static void on_before_iterate(struct pw_listener *listener, struct pw_loop *loop)
{
	struct impl *this = SPA_CONTAINER_OF(listener, struct impl, before_iterate);
	struct native_client *client, *tmp;

	spa_list_for_each_safe(client, tmp, &this->client_list, link)
		pw_connection_flush(client->connection);
}

static void
connection_data(struct spa_loop_utils *utils,
		struct spa_source *source, int fd, enum spa_io mask, void *data)
{
	struct native_client *client = data;

	if (mask & (SPA_IO_ERR | SPA_IO_HUP)) {
		pw_log_error("protocol-native %p: got connection error", client->impl);
		client_destroy(client);
		return;
	}

	if (mask & SPA_IO_IN)
		process_messages(client);
}

static struct native_client *client_new(struct impl *impl, int fd)
{
	struct native_client *this;
	struct pw_client *client;
	socklen_t len;
	struct ucred ucred, *ucredp;

	this = calloc(1, sizeof(struct native_client));
	if (this == NULL)
		goto no_native_client;

	this->impl = impl;
	this->fd = fd;
	this->source = pw_loop_add_io(impl->core->main_loop->loop,
				      this->fd,
				      SPA_IO_ERR | SPA_IO_HUP, false, connection_data, this);
	if (this->source == NULL)
		goto no_source;

	this->connection = pw_connection_new(fd);
	if (this->connection == NULL)
		goto no_connection;

	len = sizeof(ucred);
	if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &len) < 0) {
		pw_log_error("no peercred: %m");
		ucredp = NULL;
	} else {
		ucredp = &ucred;
	}

	client = pw_client_new(impl->core, ucredp, NULL);
	if (client == NULL)
		goto no_client;

	client->protocol_private = this->connection;

	this->client = client;

	spa_list_insert(impl->client_list.prev, &this->link);

	pw_signal_add(&client->resource_added, &this->resource_added, on_resource_added);
	pw_signal_add(&client->busy_changed, &this->busy_changed, on_busy_changed);

	pw_global_bind(impl->core->global, client, 0, 0);
	return this;

      no_client:
	pw_connection_destroy(this->connection);
      no_connection:
	pw_loop_destroy_source(impl->core->main_loop->loop, this->source);
      no_source:
	free(this);
      no_native_client:
	return NULL;
}

static struct socket *create_socket(void)
{
	struct socket *s;

	if ((s = calloc(1, sizeof(struct socket))) == NULL)
		return NULL;

	s->fd = -1;
	s->fd_lock = -1;
	return s;
}

static void destroy_socket(struct socket *s)
{
	if (s->source)
		pw_loop_destroy_source(s->loop, s->source);
	if (s->addr.sun_path[0])
		unlink(s->addr.sun_path);
	if (s->fd >= 0)
		close(s->fd);
	if (s->lock_addr[0])
		unlink(s->lock_addr);
	if (s->fd_lock >= 0)
		close(s->fd_lock);
	free(s);
}

static bool init_socket_name(struct socket *s, const char *name)
{
	int name_size;
	const char *runtime_dir;

	if ((runtime_dir = getenv("XDG_RUNTIME_DIR")) == NULL) {
		pw_log_error("XDG_RUNTIME_DIR not set in the environment");
		return false;
	}

	s->addr.sun_family = AF_LOCAL;
	name_size = snprintf(s->addr.sun_path, sizeof(s->addr.sun_path),
			     "%s/%s", runtime_dir, name) + 1;

	s->core_name = (s->addr.sun_path + name_size - 1) - strlen(name);

	if (name_size > (int) sizeof(s->addr.sun_path)) {
		pw_log_error("socket path \"%s/%s\" plus null terminator exceeds 108 bytes",
			     runtime_dir, name);
		*s->addr.sun_path = 0;
		return false;
	}
	return true;
}

static bool lock_socket(struct socket *s)
{
	struct stat socket_stat;

	snprintf(s->lock_addr, sizeof(s->lock_addr), "%s%s", s->addr.sun_path, LOCK_SUFFIX);

	s->fd_lock = open(s->lock_addr, O_CREAT | O_CLOEXEC,
			  (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP));

	if (s->fd_lock < 0) {
		pw_log_error("unable to open lockfile %s check permissions", s->lock_addr);
		goto err;
	}

	if (flock(s->fd_lock, LOCK_EX | LOCK_NB) < 0) {
		pw_log_error("unable to lock lockfile %s, maybe another daemon is running",
			     s->lock_addr);
		goto err_fd;
	}

	if (stat(s->addr.sun_path, &socket_stat) < 0) {
		if (errno != ENOENT) {
			pw_log_error("did not manage to stat file %s\n", s->addr.sun_path);
			goto err_fd;
		}
	} else if (socket_stat.st_mode & S_IWUSR || socket_stat.st_mode & S_IWGRP) {
		unlink(s->addr.sun_path);
	}
	return true;

      err_fd:
	close(s->fd_lock);
	s->fd_lock = -1;
      err:
	*s->lock_addr = 0;
	*s->addr.sun_path = 0;
	return false;
}

static void
socket_data(struct spa_loop_utils *utils,
	    struct spa_source *source, int fd, enum spa_io mask, void *data)
{
	struct impl *impl = data;
	struct native_client *client;
	struct sockaddr_un name;
	socklen_t length;
	int client_fd;

	length = sizeof(name);
	client_fd = accept4(fd, (struct sockaddr *) &name, &length, SOCK_CLOEXEC);
	if (client_fd < 0) {
		pw_log_error("failed to accept: %m");
		return;
	}

	client = client_new(impl, client_fd);
	if (client == NULL) {
		pw_log_error("failed to create client");
		close(client_fd);
		return;
	}

	pw_loop_update_io(impl->core->main_loop->loop,
			  client->source, SPA_IO_IN | SPA_IO_ERR | SPA_IO_HUP);
}

static bool add_socket(struct impl *impl, struct socket *s)
{
	socklen_t size;

	if ((s->fd = socket(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0)) < 0)
		return false;

	size = offsetof(struct sockaddr_un, sun_path) +strlen(s->addr.sun_path);
	if (bind(s->fd, (struct sockaddr *) &s->addr, size) < 0) {
		pw_log_error("bind() failed with error: %m");
		return false;
	}

	if (listen(s->fd, 128) < 0) {
		pw_log_error("listen() failed with error: %m");
		return false;
	}

	s->loop = impl->core->main_loop->loop;
	s->source = pw_loop_add_io(s->loop, s->fd, SPA_IO_IN, false, socket_data, impl);
	if (s->source == NULL)
		return false;

	spa_list_insert(impl->socket_list.prev, &s->link);

	return true;
}


static struct impl *pw_protocol_native_new(struct pw_core *core, struct pw_properties *properties)
{
	struct impl *impl;
	struct socket *s;
	const char *name;

	impl = calloc(1, sizeof(struct impl));
	pw_log_debug("protocol-native %p: new", impl);

	impl->core = core;
	impl->properties = properties;

	name = NULL;
	if (impl->properties)
		name = pw_properties_get(impl->properties, "pipewire.core.name");
	if (name == NULL)
		name = getenv("PIPEWIRE_CORE");
	if (name == NULL)
		name = "pipewire-0";

	s = create_socket();

	spa_list_init(&impl->socket_list);
	spa_list_init(&impl->client_list);

	if (!init_socket_name(s, name))
		goto error;

	if (!lock_socket(s))
		goto error;

	if (!add_socket(impl, s))
		goto error;

	pw_signal_add(&impl->core->main_loop->loop->before_iterate,
		      &impl->before_iterate, on_before_iterate);

	return impl;

      error:
	destroy_socket(s);
	free(impl);
	return NULL;
}

#if 0
static void pw_protocol_native_destroy(struct impl *impl)
{
	struct impl *object, *tmp;

	pw_log_debug("protocol-native %p: destroy", impl);

	pw_signal_remove(&impl->before_iterate);

	pw_global_destroy(impl->global);

	spa_list_for_each_safe(object, tmp, &impl->object_list, link)
	    object_destroy(object);

	free(impl);
}
#endif

bool pipewire__module_init(struct pw_module *module, const char *args)
{
	pw_protocol_native_new(module->core, NULL);
	return true;
}