xref: /external/adhd/cras/src/libcras/cras_client.c

/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/*
 * Basic playback flow:
 *  cras_client_create - Create new structure and set to defaults.
 *  cras_client_connect - Connect client to server - sets up server_fd to
 *    communicate with the audio server.  After the client connects, the server
 *    will send back a message containing the client id.
 *  cras_client_add_stream - Add a playback or capture stream. Creates a
 *    client_stream struct and send a file descriptor to server. That file
 *    descriptor and aud_fd are a pair created from socketpair().
 *  client_connected - The server will send a connected message to indicate that
 *    the client should start receving audio events from aud_fd. This message
 *    also specifies the shared memory region to use to share audio samples.
 *    This region will be shmat'd.
 *  running - Once the connections are established, the client will listen for
 *    requests on aud_fd and fill the shm region with the requested number of
 *    samples. This happens in the aud_cb specified in the stream parameters.
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE /* For ppoll() */
#endif

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <poll.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdint.h>
#include <sys/eventfd.h>
#include <sys/ipc.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/signal.h>
#include <sys/socket.h>
#include <sys/timerfd.h>
#include <sys/types.h>
#include <sys/un.h>
#include <syslog.h>
#include <unistd.h>

#include "cras_client.h"
#include "cras_config.h"
#include "cras_file_wait.h"
#include "cras_messages.h"
#include "cras_observer_ops.h"
#include "cras_shm.h"
#include "cras_types.h"
#include "cras_util.h"
#include "utlist.h"

static const size_t MAX_CMD_MSG_LEN = 256;
static const size_t SERVER_SHUTDOWN_TIMEOUT_US = 500000;
static const size_t SERVER_CONNECT_TIMEOUT_MS = 1000;

/* Commands sent from the user to the running client. */
enum {
	CLIENT_STOP,
	CLIENT_ADD_STREAM,
	CLIENT_REMOVE_STREAM,
	CLIENT_SET_STREAM_VOLUME_SCALER,
	CLIENT_SERVER_CONNECT,
	CLIENT_SERVER_CONNECT_ASYNC,
};

struct command_msg {
	unsigned len;
	unsigned msg_id;
	cras_stream_id_t stream_id;
};

struct set_stream_volume_command_message {
	struct command_msg header;
	float volume_scaler;
};

/* Adds a stream to the client.
 *  stream - The stream to add.
 *  stream_id_out - Filled with the stream id of the new stream.
 *  dev_idx - Index of the device to attach the newly created stream.
 *      NO_DEVICE means not to pin the stream to a device.
 */
struct add_stream_command_message {
	struct command_msg header;
	struct client_stream *stream;
	cras_stream_id_t *stream_id_out;
	uint32_t dev_idx;
};

/* Commands send from a running stream to the client. */
enum {
	CLIENT_STREAM_EOF,
};

struct stream_msg {
	unsigned msg_id;
	cras_stream_id_t stream_id;
};

enum CRAS_THREAD_STATE {
	CRAS_THREAD_STOP,	/* Isn't (shouldn't be) running. */
	CRAS_THREAD_WARMUP,	/* Is started, but not fully functional: waiting
				 * for resources to be ready for example. */
	CRAS_THREAD_RUNNING,	/* Is running and fully functional. */
};

/* Manage information for a thread. */
struct thread_state {
	pthread_t tid;
	enum CRAS_THREAD_STATE state;
};

/* Parameters used when setting up a capture or playback stream. See comment
 * above cras_client_create_stream_params in the header for descriptions. */
struct cras_stream_params {
	enum CRAS_STREAM_DIRECTION direction;
	size_t buffer_frames;
	size_t cb_threshold;
	enum CRAS_STREAM_TYPE stream_type;
	uint32_t flags;
	void *user_data;
	cras_playback_cb_t aud_cb;
	cras_unified_cb_t unified_cb;
	cras_error_cb_t err_cb;
	struct cras_audio_format format;
};

/* Represents an attached audio stream.
 * id - Unique stream identifier.
 * aud_fd - After server connects audio messages come in here.
 * direction - playback, capture, both, or loopback (see CRAS_STREAM_DIRECTION).
 * flags - Currently not used.
 * volume_scaler - Amount to scale the stream by, 0.0 to 1.0.
 * tid - Thread id of the audio thread spawned for this stream.
 * running - Audio thread runs while this is non-zero.
 * wake_fds - Pipe to wake the audio thread.
 * client - The client this stream is attached to.
 * config - Audio stream configuration.
 * capture_shm - Shared memory used to exchange audio samples with the server.
 * play_shm - Shared memory used to exchange audio samples with the server.
 * prev, next - Form a linked list of streams attached to a client.
 */
struct client_stream {
	cras_stream_id_t id;
	int aud_fd; /* audio messages from server come in here. */
	enum CRAS_STREAM_DIRECTION direction;
	uint32_t flags;
	float volume_scaler;
	struct thread_state thread;
	int wake_fds[2]; /* Pipe to wake the thread */
	struct cras_client *client;
	struct cras_stream_params *config;
	struct cras_audio_shm capture_shm;
	int capture_shm_size;
	struct cras_audio_shm play_shm;
	int play_shm_size;
	struct client_stream *prev, *next;
};

/* State of the socket. */
typedef enum cras_socket_state {
	CRAS_SOCKET_STATE_DISCONNECTED,
		/* Not connected. Also used to cleanup the current connection
		 * before restarting the connection attempt. */
	CRAS_SOCKET_STATE_WAIT_FOR_SOCKET,
		/* Waiting for the socket file to exist. Socket file existence
		 * is monitored using cras_file_wait. */
	CRAS_SOCKET_STATE_WAIT_FOR_WRITABLE,
		/* Waiting for the socket to have something at the other end. */
	CRAS_SOCKET_STATE_FIRST_MESSAGE,
		/* Waiting for the first messages from the server and set our
		 * client ID. */
	CRAS_SOCKET_STATE_CONNECTED,
		/* The socket is connected and working. */
	CRAS_SOCKET_STATE_ERROR_DELAY,
		/* There was an error during one of the above states. Sleep for
		 * a bit before continuing. If this state could not be initiated
		 * then we move to the DISCONNECTED state and notify via the
		 * connection callback. */
} cras_socket_state_t;

/* Represents a client used to communicate with the audio server.
 * id - Unique identifier for this client, negative until connected.
 * server_fd - Incoming messages from server.
 * server_fd_state - State of the server's socket.
 * server_event_fd - Eventfd to wait on until a connection is established.
 * stream_fds - Pipe for attached streams.
 * command_fds - Pipe for user commands to thread.
 * command_reply_fds - Pipe for acking/nacking command messages from thread.
 * sock_file - Server communication socket file.
 * sock_file_wait - Structure used to monitor existence of the socket file.
 * sock_file_exists - Set to true when the socket file exists.
 * running - The client thread will run while this is non zero.
 * next_stream_id - ID to give the next stream.
 * stream_start_cond - Condition used during stream startup.
 * stream_start_lock - Lock used during stream startup.
 * tid - Thread ID of the client thread started by "cras_client_run_thread".
 * last_command_result - Passes back the result of the last user command.
 * streams - Linked list of streams attached to this client.
 * server_state - RO shared memory region holding server state.
 * debug_info_callback - Function to call when debug info is received.
 * get_hotword_models_cb_t - Function to call when hotword models info is ready.
 * server_err_cb - Function to call when failed to read messages from server.
 * server_err_user_arg - User argument for server_err_cb.
 * server_connection_cb - Function to called when a connection state changes.
 * server_connection_user_arg - User argument for server_connection_cb.
 * thread_priority_cb - Function to call for setting audio thread priority.
 * observer_ops - Functions to call when system state changes.
 * observer_context - Context passed to client in state change callbacks.
 */
struct cras_client {
	int id;
	int server_fd;
	cras_socket_state_t server_fd_state;
	int server_event_fd;
	int stream_fds[2];
	int command_fds[2];
	int command_reply_fds[2];
	const char *sock_file;
	struct cras_file_wait *sock_file_wait;
	bool sock_file_exists;
	struct thread_state thread;
	cras_stream_id_t next_stream_id;
	pthread_cond_t stream_start_cond;
	pthread_mutex_t stream_start_lock;
	int last_command_result;
	struct client_stream *streams;
	const struct cras_server_state *server_state;
	void (*debug_info_callback)(struct cras_client *);
	get_hotword_models_cb_t get_hotword_models_cb;
	cras_server_error_cb_t server_err_cb;
	cras_connection_status_cb_t server_connection_cb;
	void *server_connection_user_arg;
	cras_thread_priority_cb_t thread_priority_cb;
	struct cras_observer_ops observer_ops;
	void *observer_context;
};

/*
 * Holds the client pointer plus internal book keeping.
 *
 * client - The client
 * server_state_rwlock - lock to make the client's server_state thread-safe.
 */
struct client_int {
	struct cras_client client;
	pthread_rwlock_t server_state_rwlock;
};

#define to_client_int(cptr) \
((struct client_int *)((char *)cptr - offsetof(struct client_int, client)))

/*
 * Local Helpers
 */

static int client_thread_rm_stream(struct cras_client *client,
				   cras_stream_id_t stream_id);
static int handle_message_from_server(struct cras_client *client);
static int reregister_notifications(struct cras_client *client);

/*
 * Unlock the server_state_rwlock if lock_rc is 0.
 *
 * Args:
 *    client - The CRAS client pointer.
 *    lock_rc - The result of server_state_rdlock or
 *              server_state_wrlock.
 */
static void server_state_unlock(const struct cras_client *client,
				int lock_rc)
{
	struct client_int *client_int;

	if (!client)
		return;
	client_int = to_client_int(client);
	if (lock_rc == 0)
		pthread_rwlock_unlock(&client_int->server_state_rwlock);
}

/*
 * Lock the server_state_rwlock for reading.
 *
 * Also checks that the server_state pointer is valid.
 *
 * Args:
 *    client - The CRAS client pointer.
 * Returns:
 *    0 for success, positive error code on error.
 *    Returns EINVAL if the server state pointer is NULL.
 */
static int server_state_rdlock(const struct cras_client *client)
{
	struct client_int *client_int;
	int lock_rc;

	if (!client)
		return EINVAL;
	client_int = to_client_int(client);
	lock_rc = pthread_rwlock_rdlock(&client_int->server_state_rwlock);
	if (lock_rc != 0)
		return lock_rc;
	if (!client->server_state) {
		pthread_rwlock_unlock(&client_int->server_state_rwlock);
		return EINVAL;
	}
	return 0;
}

/*
 * Lock the server_state_rwlock for writing.
 *
 * Args:
 *    client - The CRAS client pointer.
 * Returns:
 *    0 for success, positive error code on error.
 */
static int server_state_wrlock(const struct cras_client *client)
{
	struct client_int *client_int;

	if (!client)
		return EINVAL;
	client_int = to_client_int(client);
	return pthread_rwlock_wrlock(&client_int->server_state_rwlock);
}

/* Get the stream pointer from a stream id. */
static struct client_stream *stream_from_id(const struct cras_client *client,
					    unsigned int id)
{
	struct client_stream *out;

	DL_SEARCH_SCALAR(client->streams, out, id, id);
	return out;
}

/*
 * Fill a pollfd structure with the current server fd and events.
 */
void server_fill_pollfd(const struct cras_client *client,
			struct pollfd *poll_fd)
{
	int events = 0;

	poll_fd->fd = client->server_fd;
	switch (client->server_fd_state) {
	case CRAS_SOCKET_STATE_DISCONNECTED:
		break;
	case CRAS_SOCKET_STATE_WAIT_FOR_SOCKET:
	case CRAS_SOCKET_STATE_FIRST_MESSAGE:
	case CRAS_SOCKET_STATE_CONNECTED:
	case CRAS_SOCKET_STATE_ERROR_DELAY:
		events = POLLIN;
		break;
	case CRAS_SOCKET_STATE_WAIT_FOR_WRITABLE:
		events = POLLOUT;
		break;
	}
	poll_fd->events = events;
	poll_fd->revents = 0;
}

/*
 * Change the server_fd_state.
 */
static void server_fd_move_to_state(struct cras_client *client,
				    cras_socket_state_t state)
{
	if (state == client->server_fd_state)
		return;

	client->server_fd_state = state;
}

/*
 * Action to take when in state ERROR_DELAY.
 *
 * In this state we want to sleep for a few seconds before retrying the
 * connection to the audio server.
 *
 * If server_fd is negative: create a timer and setup server_fd with the
 * timer's fd. If server_fd is not negative and there is input, then assume
 * that the timer has expired, and restart the connection by moving to
 * WAIT_FOR_SOCKET state.
 */
static int error_delay_next_action(struct cras_client *client,
				   int poll_revents)
{
	int rc;
	struct itimerspec timeout;

	if (client->server_fd == -1) {
		client->server_fd = timerfd_create(
					CLOCK_MONOTONIC,
					TFD_NONBLOCK|TFD_CLOEXEC);
		if (client->server_fd == -1) {
			rc = -errno;
			syslog(LOG_ERR,
			       "cras_client: Could not create timerfd: %s",
			       strerror(-rc));
			return rc;
		}

		/* Setup a relative timeout of 2 seconds. */
		memset(&timeout, 0, sizeof(timeout));
		timeout.it_value.tv_sec = 2;
		rc = timerfd_settime(client->server_fd, 0, &timeout, NULL);
		if (rc != 0) {
			rc = -errno;
			syslog(LOG_ERR,
			       "cras_client: Could not set timeout: %s",
			       strerror(-rc));
			return rc;
		}
		return 0;
	} else if ((poll_revents & POLLIN) == 0) {
		return 0;
	}

	/* Move to the next state: close the timer fd first. */
	close(client->server_fd);
	client->server_fd = -1;
	server_fd_move_to_state(client, CRAS_SOCKET_STATE_WAIT_FOR_SOCKET);
	return 0;
}

/*
 * Action to take when in WAIT_FOR_SOCKET state.
 *
 * In this state we are waiting for the socket file to exist. The existence of
 * the socket file is continually monitored using the cras_file_wait structure
 * and a separate fd. When the sock_file_exists boolean is modified, the state
 * machine is invoked.
 *
 * If the socket file exists, then we move to the WAIT_FOR_WRITABLE state.
 */
static void wait_for_socket_next_action(struct cras_client *client)
{
	if (client->sock_file_exists)
		server_fd_move_to_state(
			client, CRAS_SOCKET_STATE_WAIT_FOR_WRITABLE);
}

/*
 * Action to take when in WAIT_FOR_WRITABLE state.
 *
 * In this state we are initiating a connection the server and waiting for the
 * server to ready for incoming messages.
 *
 * Create the socket to the server, and wait while a connect request results in
 * -EINPROGRESS. Otherwise, we assume that the socket file will be deleted by
 * the server and the server_fd_state will be changed in
 * sock_file_wait_dispatch().
 */
static int wait_for_writable_next_action(struct cras_client *client,
					 int poll_revents)
{
	int rc;
	struct sockaddr_un address;

	if (client->server_fd == -1) {
		client->server_fd = socket(PF_UNIX, SOCK_SEQPACKET, 0);
		if (client->server_fd < 0) {
			rc = -errno;
			syslog(LOG_ERR, "cras_client: server socket failed: %s",
			       strerror(-rc));
			return rc;
		}
	}
	else if ((poll_revents & POLLOUT) == 0) {
		return 0;
	}

	/* We make the file descriptor non-blocking when we do connect(), so we
	 * don't block indefinitely. */
	cras_make_fd_nonblocking(client->server_fd);

	memset(&address, 0, sizeof(struct sockaddr_un));
	address.sun_family = AF_UNIX;
	strcpy(address.sun_path, client->sock_file);
	rc = connect(client->server_fd, (struct sockaddr *)&address,
		     sizeof(struct sockaddr_un));
	if (rc != 0) {
		rc = -errno;
		/* For -EINPROGRESS, we wait for POLLOUT on the server_fd.
		 * Otherwise CRAS is not running and we assume that the socket
		 * file will be deleted and recreated. Notification of that will
		 * happen via the sock_file_wait_dispatch(). */
		if (rc == -ECONNREFUSED) {
			/* CRAS is not running, don't log this error and just
			 * stay in this state waiting sock_file_wait_dispatch()
			 * to move the state machine. */
			close(client->server_fd);
			client->server_fd = -1;
		}
		else if (rc != -EINPROGRESS) {
			syslog(LOG_ERR,
			       "cras_client: server connect failed: %s",
			       strerror(-rc));
			return rc;
		}
		return 0;
	}

	cras_make_fd_blocking(client->server_fd);
	server_fd_move_to_state(client, CRAS_SOCKET_STATE_FIRST_MESSAGE);
	return 0;
}

/*
 * Action to take when transitioning to the CONNECTED state.
 */
static int connect_transition_action(struct cras_client *client)
{
	eventfd_t event_value;
	int rc;

	rc = reregister_notifications(client);
	if (rc < 0)
		return rc;

	server_fd_move_to_state(client, CRAS_SOCKET_STATE_CONNECTED);
	/* Notify anyone waiting on this state change that we're
	 * connected. */
	eventfd_read(client->server_event_fd, &event_value);
	eventfd_write(client->server_event_fd, 1);
	if (client->server_connection_cb)
		client->server_connection_cb(
				client, CRAS_CONN_STATUS_CONNECTED,
				client->server_connection_user_arg);
	return 0;
}

/*
 * Action to take when in the FIRST_MESSAGE state.
 *
 * We are waiting for the first message from the server. When our client ID has
 * been set, then we can move to the CONNECTED state.
 */
static int first_message_next_action(struct cras_client *client,
				     int poll_revents)
{
	int rc;

	if (client->server_fd < 0)
		return -EINVAL;

	if ((poll_revents & POLLIN) == 0)
		return 0;

	rc = handle_message_from_server(client);
	if (rc < 0) {
		syslog(LOG_ERR, "handle first message: %s", strerror(-rc));
	} else if (client->id >= 0) {
		rc = connect_transition_action(client);
	} else {
		syslog(LOG_ERR, "did not get ID after first message!");
		rc = -EINVAL;
	}
	return rc;
}

/*
 * Play nice and shutdown the server socket.
 */
static inline int shutdown_and_close_socket(int sockfd)
{
	int rc;
	uint8_t buffer[CRAS_CLIENT_MAX_MSG_SIZE];
	struct timeval tv;

	tv.tv_sec = 0;
	tv.tv_usec = SERVER_SHUTDOWN_TIMEOUT_US;
	setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv, sizeof(tv));

	rc = shutdown(sockfd, SHUT_WR);
	if (rc < 0)
		return rc;
	/* Wait until the socket is closed by the peer. */
	for (;;) {
		rc = recv(sockfd, buffer, sizeof(buffer), 0);
		if (rc <= 0)
			break;
	}
	return close(sockfd);
}

/*
 * Action to take when disconnecting from the server.
 *
 * Clean up the server socket, and the server_state pointer. Move to the next
 * logical state.
 */
static void disconnect_transition_action(struct cras_client *client, bool force)
{
	eventfd_t event_value;
	cras_socket_state_t old_state = client->server_fd_state;
	struct client_stream *s;
	int lock_rc;

	/* Stop all playing streams.
	 * TODO(muirj): Pause and resume streams. */
	DL_FOREACH(client->streams, s) {
		s->config->err_cb(client, s->id, -ENOTCONN,
				  s->config->user_data);
		client_thread_rm_stream(client, s->id);
	}

	/* Clean up the server_state pointer. */
	lock_rc = server_state_wrlock(client);
	if (client->server_state) {
		munmap((void *)client->server_state,
		       sizeof(*client->server_state));
		client->server_state = NULL;
	}
	server_state_unlock(client, lock_rc);

	/* Our ID is unknown now. */
	client->id = -1;

	/* Clean up the server fd. */
	if (client->server_fd >= 0) {
		if (!force)
			shutdown_and_close_socket(client->server_fd);
		else
			close(client->server_fd);
		client->server_fd = -1;
	}

	/* Reset the server_event_fd value to 0 (and cause subsequent threads
	 * waiting on the connection to wait). */
	eventfd_read(client->server_event_fd, &event_value);

	switch (old_state) {
	case CRAS_SOCKET_STATE_DISCONNECTED:
		/* Do nothing: already disconnected. */
		break;
	case CRAS_SOCKET_STATE_ERROR_DELAY:
		/* We're disconnected and there was a failure to setup
		 * automatic reconnection, so call the server error
		 * callback now. */
		server_fd_move_to_state(
			client, CRAS_SOCKET_STATE_DISCONNECTED);
		if (client->server_connection_cb)
			client->server_connection_cb(
					client, CRAS_CONN_STATUS_FAILED,
					client->server_connection_user_arg);
		else if (client->server_err_cb)
			client->server_err_cb(
				client, client->server_connection_user_arg);
		break;
	case CRAS_SOCKET_STATE_WAIT_FOR_SOCKET:
	case CRAS_SOCKET_STATE_WAIT_FOR_WRITABLE:
	case CRAS_SOCKET_STATE_FIRST_MESSAGE:
		/* We are running this state transition while a connection is
		 * in progress for an error case. When there is no error, we
		 * come into this function in the DISCONNECTED state. */
		server_fd_move_to_state(
			client, CRAS_SOCKET_STATE_ERROR_DELAY);
		break;
	case CRAS_SOCKET_STATE_CONNECTED:
		/* Disconnected from CRAS (for an error), wait for the socket
		 * file to be (re)created. */
		server_fd_move_to_state(
			client, CRAS_SOCKET_STATE_WAIT_FOR_SOCKET);
		/* Notify the caller that we aren't connected anymore. */
		if (client->server_connection_cb)
			client->server_connection_cb(
					client, CRAS_CONN_STATUS_DISCONNECTED,
					client->server_connection_user_arg);
		break;
	}
}

static int server_fd_dispatch(struct cras_client *client, int poll_revents)
{
	int rc = 0;
	cras_socket_state_t old_state;

	if ((poll_revents & POLLHUP) != 0) {
		/* Error or disconnect: cleanup and make a state change now. */
		disconnect_transition_action(client, true);
	}
	old_state = client->server_fd_state;

	switch (client->server_fd_state) {
	case CRAS_SOCKET_STATE_DISCONNECTED:
		/* Assume that we've taken the necessary actions. */
		return -ENOTCONN;
	case CRAS_SOCKET_STATE_ERROR_DELAY:
		rc = error_delay_next_action(client, poll_revents);
		break;
	case CRAS_SOCKET_STATE_WAIT_FOR_SOCKET:
		wait_for_socket_next_action(client);
		break;
	case CRAS_SOCKET_STATE_WAIT_FOR_WRITABLE:
		rc = wait_for_writable_next_action(client, poll_revents);
		break;
	case CRAS_SOCKET_STATE_FIRST_MESSAGE:
		rc = first_message_next_action(client, poll_revents);
		break;
	case CRAS_SOCKET_STATE_CONNECTED:
		if ((poll_revents & POLLIN) != 0)
			rc = handle_message_from_server(client);
		break;
	}

	if (rc != 0) {
		/* If there is an error, then start-over. */
		rc = server_fd_dispatch(client, POLLHUP);
	} else if (old_state != client->server_fd_state) {
		/* There was a state change, process the new state now. */
		rc = server_fd_dispatch(client, 0);
	}
	return rc;
}

/*
 * Start connecting to the server if we aren't already.
 */
static int server_connect(struct cras_client *client)
{
	if (client->server_fd_state != CRAS_SOCKET_STATE_DISCONNECTED)
		return 0;
	/* Start waiting for the server socket to exist. */
	server_fd_move_to_state(client, CRAS_SOCKET_STATE_WAIT_FOR_SOCKET);
	return server_fd_dispatch(client, 0);
}

/*
 * Disconnect from the server if we haven't already.
 */
static void server_disconnect(struct cras_client *client)
{
	if (client->server_fd_state == CRAS_SOCKET_STATE_DISCONNECTED)
		return;
	/* Set the disconnected state first so that the disconnect
	 * transition doesn't move the server state to ERROR_DELAY. */
	server_fd_move_to_state(client, CRAS_SOCKET_STATE_DISCONNECTED);
	disconnect_transition_action(client, false);
}

/*
 * Called when something happens to the socket file.
 */
static void sock_file_wait_callback(void *context, cras_file_wait_event_t event,
				    const char *filename)
{
	struct cras_client *client = (struct cras_client *)context;
	switch (event) {
	case CRAS_FILE_WAIT_EVENT_CREATED:
		client->sock_file_exists = 1;
		switch (client->server_fd_state) {
		case CRAS_SOCKET_STATE_DISCONNECTED:
		case CRAS_SOCKET_STATE_ERROR_DELAY:
		case CRAS_SOCKET_STATE_FIRST_MESSAGE:
		case CRAS_SOCKET_STATE_CONNECTED:
			break;
		case CRAS_SOCKET_STATE_WAIT_FOR_SOCKET:
		case CRAS_SOCKET_STATE_WAIT_FOR_WRITABLE:
			/* The socket file exists. Tell the server state
			 * machine. */
			server_fd_dispatch(client, 0);
			break;
		}
		break;
	case CRAS_FILE_WAIT_EVENT_DELETED:
		client->sock_file_exists = 0;
		switch (client->server_fd_state) {
		case CRAS_SOCKET_STATE_DISCONNECTED:
			break;
		case CRAS_SOCKET_STATE_WAIT_FOR_SOCKET:
		case CRAS_SOCKET_STATE_WAIT_FOR_WRITABLE:
		case CRAS_SOCKET_STATE_ERROR_DELAY:
		case CRAS_SOCKET_STATE_FIRST_MESSAGE:
		case CRAS_SOCKET_STATE_CONNECTED:
			/* Restart the connection process. */
			server_disconnect(client);
			server_connect(client);
			break;
		}
		break;
	case CRAS_FILE_WAIT_EVENT_NONE:
		break;
	}
}

/*
 * Service the sock_file_wait's fd.
 *
 * If the socket file is deleted, then cause a disconnect from the server.
 * Otherwise, start a reconnect depending on the server_fd_state.
 */
static int sock_file_wait_dispatch(struct cras_client *client,
				   int poll_revents)
{
	int rc;

	if ((poll_revents & POLLIN) == 0)
		return 0;

	rc = cras_file_wait_dispatch(client->sock_file_wait);
	if (rc == -EAGAIN || rc == -EWOULDBLOCK)
		rc = 0;
	else if (rc != 0)
		syslog(LOG_ERR, "cras_file_wait_dispatch: %s", strerror(-rc));
	return rc;
}

/*
 * Waits until we have heard back from the server so that we know we are
 * connected.
 *
 * The connected success/failure message is always the first message the server
 * sends. Return non zero if client is connected to the server. A return code
 * of zero means that the client is not connected to the server.
 */
static int check_server_connected_wait(struct cras_client *client,
				       struct timespec *timeout)
{
	int rc = 0;
	struct pollfd poll_fd;

	poll_fd.fd = client->server_event_fd;
	poll_fd.events = POLLIN;
	poll_fd.revents = 0;

	/* The server_event_fd is only read and written by the functions
	 * that connect to the server. When a connection is established the
	 * eventfd has a value of 1 and cras_poll will return immediately
	 * with 1. When there is no connection to the server, then this
	 * function waits until the timeout has expired or a non-zero value
	 * is written to the server_event_fd. */
	while (rc == 0)
		rc = cras_poll(&poll_fd, 1, timeout, NULL);
	return rc > 0;
}

/* Returns non-zero if the thread is running (not stopped). */
static inline int thread_is_running(struct thread_state *thread)
{
	return thread->state != CRAS_THREAD_STOP;
}

/*
 * Opens the server socket and connects to it.
 * Args:
 *    client - Client pointer created with cras_client_create().
 *    timeout - Connection timeout.
 * Returns:
 *    0 for success, negative error code on failure.
 */
static int connect_to_server(struct cras_client *client,
			     struct timespec *timeout,
			     bool use_command_thread)
{
	int rc;
	struct pollfd poll_fd[2];
	struct timespec connected_timeout;

	if (!client)
		return -EINVAL;

	if (thread_is_running(&client->thread) && use_command_thread) {
		rc = cras_client_connect_async(client);
		if (rc == 0) {
			rc = check_server_connected_wait(client, timeout);
			return rc ? 0 : -ESHUTDOWN;
		}
	}

	connected_timeout.tv_sec = 0;
	connected_timeout.tv_nsec = 0;
	if (check_server_connected_wait(client, &connected_timeout))
		return 0;

	poll_fd[0].fd = cras_file_wait_get_fd(client->sock_file_wait);
	poll_fd[0].events = POLLIN;

	rc = server_connect(client);
	while(rc == 0) {
		// Wait until we've connected or until there is a timeout.
		// Meanwhile handle incoming actions on our fds.

		server_fill_pollfd(client, &(poll_fd[1]));
		rc = cras_poll(poll_fd, 2, timeout, NULL);
		if (rc <= 0)
			continue;

		if (poll_fd[0].revents) {
			rc = sock_file_wait_dispatch(
					client, poll_fd[0].revents);
			continue;
		}

		if (poll_fd[1].revents) {
			rc = server_fd_dispatch(client, poll_fd[1].revents);
			if (rc == 0 &&
			    client->server_fd_state ==
					CRAS_SOCKET_STATE_CONNECTED)
				break;
		}
	}

	if (rc != 0)
		syslog(LOG_ERR, "cras_client: Connect server failed: %s",
		       strerror(-rc));

	return rc;
}

static int connect_to_server_wait_retry(struct cras_client *client,
					int timeout_ms,
					bool use_command_thread)
{
	struct timespec timeout_value;
	struct timespec *timeout;

	if (timeout_ms < 0) {
		timeout = NULL;
	} else {
		timeout = &timeout_value;
		ms_to_timespec(timeout_ms, timeout);
	}

	/* If connected, wait for the first message from the server
	 * indicating it's ready. */
	return connect_to_server(client, timeout, use_command_thread);
}

/*
 * Tries to connect to the server.  Waits for the initial message from the
 * server.  This will happen near instantaneously if the server is already
 * running.
 */
static int connect_to_server_wait(struct cras_client *client,
				  bool use_command_thread)
{
	return connect_to_server_wait_retry(
			client, SERVER_CONNECT_TIMEOUT_MS, use_command_thread);
}

/*
 * Audio thread.
 */

/* Sends a message from the stream to the client to indicate an error.
 * If the running stream encounters an error, then it must tell the client
 * to stop running it.
 */
static int send_stream_message(const struct client_stream *stream,
			       unsigned msg_id)
{
	int res;
	struct stream_msg msg;

	msg.stream_id = stream->id;
	msg.msg_id = msg_id;
	res = write(stream->client->stream_fds[1], &msg, sizeof(msg));
	if (res != sizeof(msg))
		return -EPIPE;

	return 0;
}

/* Blocks until there is data to be read from the read_fd or until woken by an
 * incoming "poke" on wake_fd. Up to "len" bytes are read into "buf". */
static int read_with_wake_fd(int wake_fd, int read_fd, uint8_t *buf, size_t len)
{
	struct pollfd pollfds[2];
	int nread = 0;
	int nfds = 1;
	int rc;
	char tmp;

	pollfds[0].fd = wake_fd;
	pollfds[0].events = POLLIN;
	if (read_fd >= 0) {
		nfds++;
		pollfds[1].fd = read_fd;
		pollfds[1].events = POLLIN;
	}

	rc = poll(pollfds, nfds, -1);
	if (rc < 0)
		return rc;
	if (read_fd >= 0 && pollfds[1].revents & POLLIN) {
		nread = read(read_fd, buf, len);
		if (nread != (int)len)
			return -EIO;
	}
	if (pollfds[0].revents & POLLIN) {
		rc = read(wake_fd, &tmp, 1);
		if (rc < 0)
			return rc;
	}

	return nread;
}
/* Check the availability and configures a capture buffer.
 * Args:
 *     stream - The input stream to configure buffer for.
 *     captured_frames - To be filled with the pointer to the beginning of
 *         captured buffer.
 *     num_frames - Number of captured frames.
 * Returns:
 *     Number of frames available in captured_frames.
 */
static unsigned int config_capture_buf(struct client_stream *stream,
				       uint8_t **captured_frames,
				       unsigned int num_frames)
{
	/* Always return the beginning of the read buffer because Chrome expects
	 * so. */
	*captured_frames = cras_shm_get_read_buffer_base(&stream->capture_shm);

	/* Don't ask for more frames than the client desires. */
	if (stream->flags & BULK_AUDIO_OK)
		num_frames = MIN(num_frames, stream->config->buffer_frames);
	else
		num_frames = MIN(num_frames, stream->config->cb_threshold);

	/* If shm readable frames is less than client requests, that means
	 * overrun has happened in server side. Don't send partial corrupted
	 * buffer to client. */
	if (cras_shm_get_curr_read_frames(&stream->capture_shm) < num_frames)
		return 0;

	return num_frames;
}

static void complete_capture_read_current(struct client_stream *stream,
					  unsigned int num_frames)
{
	cras_shm_buffer_read_current(&stream->capture_shm, num_frames);
}

/* For capture streams this handles the message signalling that data is ready to
 * be passed to the user of this stream.  Calls the audio callback with the new
 * samples, and mark them as read.
 * Args:
 *    stream - The stream the message was received for.
 *    num_frames - The number of captured frames.
 * Returns:
 *    0, unless there is a fatal error or the client declares enod of file.
 */
static int handle_capture_data_ready(struct client_stream *stream,
				     unsigned int num_frames)
{
	int frames;
	struct cras_stream_params *config;
	uint8_t *captured_frames;
	struct timespec ts;

	config = stream->config;
	/* If this message is for an output stream, log error and drop it. */
	if (!cras_stream_has_input(stream->direction)) {
		syslog(LOG_ERR, "cras_client: Play data to input\n");
		return 0;
	}

	num_frames = config_capture_buf(stream, &captured_frames, num_frames);
	if (num_frames == 0)
		return 0;

	cras_timespec_to_timespec(&ts, &stream->capture_shm.area->ts);

	if (config->unified_cb)
		frames = config->unified_cb(stream->client,
					    stream->id,
					    captured_frames,
					    NULL,
					    num_frames,
					    &ts,
					    NULL,
					    config->user_data);
	else
		frames = config->aud_cb(stream->client,
					stream->id,
					captured_frames,
					num_frames,
					&ts,
					config->user_data);
	if (frames == EOF) {
		send_stream_message(stream, CLIENT_STREAM_EOF);
		return EOF;
	}
	if (frames == 0)
		return 0;

	complete_capture_read_current(stream, frames);
	return 0;
}

/* Notifies the server that "frames" samples have been written. */
static int send_playback_reply(struct client_stream *stream,
			       unsigned int frames,
			       int error)
{
	struct audio_message aud_msg;
	int rc;

	if (!cras_stream_uses_output_hw(stream->direction))
		return 0;

	aud_msg.id = AUDIO_MESSAGE_DATA_READY;
	aud_msg.frames = frames;
	aud_msg.error = error;

	rc = write(stream->aud_fd, &aud_msg, sizeof(aud_msg));
	if (rc != sizeof(aud_msg))
		return -EPIPE;

	return 0;
}

/* For playback streams when current buffer is empty, this handles the request
 * for more samples by calling the audio callback for the thread, and signaling
 * the server that the samples have been written. */
static int handle_playback_request(struct client_stream *stream,
				   unsigned int num_frames)
{
	uint8_t *buf;
	int frames;
	int rc = 0;
	struct cras_stream_params *config;
	struct cras_audio_shm *shm = &stream->play_shm;
	struct timespec ts;

	config = stream->config;

	/* If this message is for an input stream, log error and drop it. */
	if (stream->direction != CRAS_STREAM_OUTPUT) {
		syslog(LOG_ERR, "cras_client: Record data from output\n");
		return 0;
	}

	buf = cras_shm_get_write_buffer_base(&stream->play_shm);

	/* Limit the amount of frames to the configured amount. */
	num_frames = MIN(num_frames, config->cb_threshold);

	cras_timespec_to_timespec(&ts, &shm->area->ts);

	/* Get samples from the user */
	if (config->unified_cb)
		frames = config->unified_cb(stream->client,
				stream->id,
				NULL,
				buf,
				num_frames,
				NULL,
				&ts,
				config->user_data);
	else
		frames = config->aud_cb(stream->client,
				stream->id,
				buf,
				num_frames,
				&ts,
				config->user_data);
	if (frames < 0) {
		send_stream_message(stream, CLIENT_STREAM_EOF);
		rc = frames;
		goto reply_written;
	}

	cras_shm_buffer_written_start(shm, frames);

reply_written:
	/* Signal server that data is ready, or that an error has occurred. */
	rc = send_playback_reply(stream, frames, rc);
	return rc;
}

static void audio_thread_set_priority(struct client_stream *stream)
{
	/* Use provided callback to set priority if available. */
	if (stream->client->thread_priority_cb) {
		stream->client->thread_priority_cb(stream->client);
		return;
	}

	/* Try to get RT scheduling, if that fails try to set the nice value. */
	if (cras_set_rt_scheduling(CRAS_CLIENT_RT_THREAD_PRIORITY) ||
	    cras_set_thread_priority(CRAS_CLIENT_RT_THREAD_PRIORITY))
		cras_set_nice_level(CRAS_CLIENT_NICENESS_LEVEL);
}

/* Listens to the audio socket for messages from the server indicating that
 * the stream needs to be serviced.  One of these runs per stream. */
static void *audio_thread(void *arg)
{
	struct client_stream *stream = (struct client_stream *)arg;
	int thread_terminated = 0;
	struct audio_message aud_msg;
	int aud_fd;
	int num_read;

	if (arg == NULL)
		return (void *)-EIO;

	audio_thread_set_priority(stream);

	/* Notify the control thread that we've started. */
	pthread_mutex_lock(&stream->client->stream_start_lock);
	pthread_cond_broadcast(&stream->client->stream_start_cond);
	pthread_mutex_unlock(&stream->client->stream_start_lock);

	while (thread_is_running(&stream->thread) && !thread_terminated) {
		/* While we are warming up, aud_fd may not be valid and some
		 * shared memory resources may not yet be available. */
		aud_fd = (stream->thread.state == CRAS_THREAD_WARMUP) ?
			 -1 : stream->aud_fd;
		num_read = read_with_wake_fd(stream->wake_fds[0],
					     aud_fd,
					     (uint8_t *)&aud_msg,
					     sizeof(aud_msg));
		if (num_read < 0)
			return (void *)-EIO;
		if (num_read == 0)
			continue;

		switch (aud_msg.id) {
		case AUDIO_MESSAGE_DATA_READY:
			thread_terminated = handle_capture_data_ready(
					stream,
					aud_msg.frames);
			break;
		case AUDIO_MESSAGE_REQUEST_DATA:
			thread_terminated = handle_playback_request(
					stream,
					aud_msg.frames);
			break;
		default:
			break;
		}
	}

	return NULL;
}

/* Pokes the audio thread so that it can notice if it has been terminated. */
static int wake_aud_thread(struct client_stream *stream)
{
	int rc;

	rc = write(stream->wake_fds[1], &rc, 1);
	if (rc != 1)
		return rc;
	return 0;
}

/* Stop the audio thread for the given stream.
 * Args:
 *    stream - Stream for which to stop the audio thread.
 *    join - When non-zero, attempt to join the audio thread (wait for it to
 *           complete).
 */
static void stop_aud_thread(struct client_stream *stream, int join)
{
	if (thread_is_running(&stream->thread)) {
		stream->thread.state = CRAS_THREAD_STOP;
		wake_aud_thread(stream);
		if (join)
			pthread_join(stream->thread.tid, NULL);
	}

	if (stream->wake_fds[0] >= 0) {
		close(stream->wake_fds[0]);
		close(stream->wake_fds[1]);
		stream->wake_fds[0] = -1;
	}
}

/* Start the audio thread for this stream.
 * Returns when the thread has started and is waiting.
 * Args:
 *    stream - The stream that needs an audio thread.
 * Returns:
 *    0 for success, or a negative error code.
 */
static int start_aud_thread(struct client_stream *stream)
{
	int rc;
	struct timespec future;

	rc = pipe(stream->wake_fds);
	if (rc < 0) {
		rc = -errno;
		syslog(LOG_ERR, "cras_client: pipe: %s", strerror(-rc));
		return rc;
	}

	stream->thread.state = CRAS_THREAD_WARMUP;

	pthread_mutex_lock(&stream->client->stream_start_lock);
	rc = pthread_create(&stream->thread.tid, NULL, audio_thread, stream);
	if (rc) {
		pthread_mutex_unlock(&stream->client->stream_start_lock);
		syslog(LOG_ERR,
		       "cras_client: Couldn't create audio stream: %s",
		       strerror(rc));
		stream->thread.state = CRAS_THREAD_STOP;
		stop_aud_thread(stream, 0);
		return -rc;
	}

	clock_gettime(CLOCK_MONOTONIC, &future);
	future.tv_sec += 2; /* Wait up to two seconds. */
	rc = pthread_cond_timedwait(&stream->client->stream_start_cond,
				    &stream->client->stream_start_lock, &future);
	pthread_mutex_unlock(&stream->client->stream_start_lock);
	if (rc != 0) {
		/* Something is very wrong: try to cancel the thread and don't
		 * wait for it. */
		syslog(LOG_ERR, "cras_client: Client thread not responding: %s",
		       strerror(rc));
		stop_aud_thread(stream, 0);
		return -rc;
	}
	return 0;
}

/*
 * Client thread.
 */

/* Gets the update_count of the server state shm region. */
static inline
unsigned begin_server_state_read(const struct cras_server_state *state)
{
	unsigned count;

	/* Version will be odd when the server is writing. */
	while ((count = *(volatile unsigned *)&state->update_count) & 1)
		sched_yield();
	__sync_synchronize();
	return count;
}

/* Checks if the update count of the server state shm region has changed from
 * count.  Returns 0 if the count still matches.
 */
static inline
int end_server_state_read(const struct cras_server_state *state, unsigned count)
{
	__sync_synchronize();
	if (count != *(volatile unsigned *)&state->update_count)
		return -EAGAIN;
	return 0;

}

/* Gets the shared memory region used to share audio data with the server. */
static int config_shm(struct cras_audio_shm *shm, int shm_fd, size_t size)
{
	shm->area = (struct cras_audio_shm_area *)mmap(
			NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED,
			shm_fd, 0);
	if (shm->area == (struct cras_audio_shm_area *)-1) {
		syslog(LOG_ERR,
		       "cras_client: mmap failed to map shm for stream.");
		return errno;
	}
	/* Copy server shm config locally. */
	cras_shm_copy_shared_config(shm);

	return 0;
}

/* Release shm areas if references to them are held. */
static void free_shm(struct client_stream *stream)
{
	if (stream->capture_shm.area) {
		munmap(stream->capture_shm.area, stream->capture_shm_size);
	}
	if (stream->play_shm.area) {
		munmap(stream->play_shm.area, stream->play_shm_size);
	}
	stream->capture_shm.area = NULL;
	stream->play_shm.area = NULL;
}

/* Handles the stream connected message from the server.  Check if we need a
 * format converter, configure the shared memory region, and start the audio
 * thread that will handle requests from the server. */
static int stream_connected(struct client_stream *stream,
			    const struct cras_client_stream_connected *msg,
			    const int stream_fds[2], const unsigned int num_fds)
{
	int rc;
	struct cras_audio_format mfmt;

	if (msg->err || num_fds != 2) {
		syslog(LOG_ERR, "cras_client: Error Setting up stream %d\n",
		       msg->err);
		rc = msg->err;
		goto err_ret;
	}

	unpack_cras_audio_format(&mfmt, &msg->format);

	if (cras_stream_has_input(stream->direction)) {
		rc = config_shm(&stream->capture_shm,
				stream_fds[0],
				msg->shm_max_size);
		if (rc < 0) {
			syslog(LOG_ERR,
			       "cras_client: Error configuring capture shm");
			goto err_ret;
		}
		stream->capture_shm_size = msg->shm_max_size;
	}

	if (cras_stream_uses_output_hw(stream->direction)) {
		rc = config_shm(&stream->play_shm,
				stream_fds[1],
				msg->shm_max_size);
		if (rc < 0) {
			syslog(LOG_ERR,
			       "cras_client: Error configuring playback shm");
			goto err_ret;
		}
		stream->play_shm_size = msg->shm_max_size;

		cras_shm_set_volume_scaler(&stream->play_shm,
					   stream->volume_scaler);
	}

	stream->thread.state = CRAS_THREAD_RUNNING;
	wake_aud_thread(stream);

	close(stream_fds[0]);
	close(stream_fds[1]);
	return 0;
err_ret:
	stop_aud_thread(stream, 1);
	close(stream_fds[0]);
	close(stream_fds[1]);
	free_shm(stream);
	return rc;
}

static int send_connect_message(struct cras_client *client,
				struct client_stream *stream,
				uint32_t dev_idx)
{
	int rc;
	struct cras_connect_message serv_msg;
	int sock[2] = {-1, -1};

	/* Create a socket pair for the server to notify of audio events. */
	rc = socketpair(AF_UNIX, SOCK_STREAM, 0, sock);
	if (rc != 0) {
		rc = -errno;
		syslog(LOG_ERR, "cras_client: socketpair: %s", strerror(-rc));
		goto fail;
	}

	cras_fill_connect_message(&serv_msg,
				  stream->config->direction,
				  stream->id,
				  stream->config->stream_type,
				  stream->config->buffer_frames,
				  stream->config->cb_threshold,
				  stream->flags,
				  stream->config->format,
				  dev_idx);
	rc = cras_send_with_fds(client->server_fd, &serv_msg, sizeof(serv_msg),
			       &sock[1], 1);
	if (rc != sizeof(serv_msg)) {
		rc = EIO;
		syslog(LOG_ERR,
		       "cras_client: add_stream: Send server message failed.");
		goto fail;
	}

	stream->aud_fd = sock[0];
	close(sock[1]);
	return 0;

fail:
	if (sock[0] != -1)
		close(sock[0]);
	if (sock[1] != -1)
		close(sock[1]);
	return rc;
}

/* Adds a stream to a running client.  Checks to make sure that the client is
 * attached, waits if it isn't.  The stream is prepared on the  main thread and
 * passed here. */
static int client_thread_add_stream(struct cras_client *client,
				    struct client_stream *stream,
				    cras_stream_id_t *stream_id_out,
				    uint32_t dev_idx)
{
	int rc;
	cras_stream_id_t new_id;
	struct client_stream *out;

	/* Find the hotword device index. */
	if ((stream->flags & HOTWORD_STREAM) == HOTWORD_STREAM &&
			dev_idx == NO_DEVICE) {
		int hotword_idx;
		hotword_idx = cras_client_get_first_dev_type_idx(client,
				CRAS_NODE_TYPE_HOTWORD, CRAS_STREAM_INPUT);
		if (hotword_idx < 0) {
			syslog(LOG_ERR,
			       "cras_client: add_stream: Finding hotword dev");
			return hotword_idx;
		}
		dev_idx = hotword_idx;
	}

	/* Find an available stream id. */
	do {
		new_id = cras_get_stream_id(client->id, client->next_stream_id);
		client->next_stream_id++;
		DL_SEARCH_SCALAR(client->streams, out, id, new_id);
	} while (out != NULL);

	stream->id = new_id;
	*stream_id_out = new_id;
	stream->client = client;

	/* Start the audio thread. */
	rc = start_aud_thread(stream);
	if (rc != 0)
		return rc;

	/* Start the thread associated with this stream. */
	/* send a message to the server asking that the stream be started. */
	rc = send_connect_message(client, stream, dev_idx);
	if (rc != 0) {
		stop_aud_thread(stream, 1);
		return rc;
	}

	/* Add the stream to the linked list */
	DL_APPEND(client->streams, stream);

	return 0;
}

/* Removes a stream from a running client from within the running client's
 * context. */
static int client_thread_rm_stream(struct cras_client *client,
				   cras_stream_id_t stream_id)
{
	struct cras_disconnect_stream_message msg;
	struct client_stream *stream =
		stream_from_id(client, stream_id);
	int rc;

	if (stream == NULL)
		return 0;

	/* Tell server to remove. */
	if (client->server_fd_state == CRAS_SOCKET_STATE_CONNECTED) {
		cras_fill_disconnect_stream_message(&msg, stream_id);
		rc = write(client->server_fd, &msg, sizeof(msg));
		if (rc < 0)
			syslog(LOG_ERR,
			       "cras_client: error removing stream from server\n");
	}

	/* And shut down locally. */
	stop_aud_thread(stream, 1);

	free_shm(stream);

	DL_DELETE(client->streams, stream);
	if (stream->aud_fd >= 0)
		close(stream->aud_fd);

	free(stream->config);
	free(stream);

	return 0;
}

/* Sets the volume scaling factor for a playing stream. */
static int client_thread_set_stream_volume(struct cras_client *client,
					   cras_stream_id_t stream_id,
					   float volume_scaler)
{
	struct client_stream *stream;

	stream = stream_from_id(client, stream_id);
	if (stream == NULL || volume_scaler > 1.0 || volume_scaler < 0.0)
		return -EINVAL;

	stream->volume_scaler = volume_scaler;
	if (stream->play_shm.area != NULL)
		cras_shm_set_volume_scaler(&stream->play_shm, volume_scaler);

	return 0;
}

/* Attach to the shm region containing the server state. */
static int client_attach_shm(struct cras_client *client, int shm_fd)
{
	int lock_rc;
	int rc;

	lock_rc = server_state_wrlock(client);
	if (client->server_state) {
		rc = -EBUSY;
		goto error;
	}

	client->server_state = (struct cras_server_state *)mmap(
			NULL, sizeof(*client->server_state),
			PROT_READ, MAP_SHARED, shm_fd, 0);
	rc = -errno;
	close(shm_fd);
	if (client->server_state == (struct cras_server_state *)-1) {
		syslog(LOG_ERR,
		       "cras_client: mmap failed to map shm for client: %s",
		       strerror(-rc));
		goto error;
	}

	if (client->server_state->state_version != CRAS_SERVER_STATE_VERSION) {
		munmap((void *)client->server_state,
		       sizeof(*client->server_state));
		client->server_state = NULL;
		rc = -EINVAL;
		syslog(LOG_ERR, "cras_client: Unknown server_state version.");
	} else {
		rc = 0;
	}

error:
	server_state_unlock(client, lock_rc);
	return rc;
}

static void cras_client_get_hotword_models_ready(
		struct cras_client *client,
		const char *hotword_models)
{
	if (!client->get_hotword_models_cb)
		return;
	client->get_hotword_models_cb(client, hotword_models);
	client->get_hotword_models_cb = NULL;
}

/* Handles messages from the cras server. */
static int handle_message_from_server(struct cras_client *client)
{
	uint8_t buf[CRAS_CLIENT_MAX_MSG_SIZE];
	struct cras_client_message *msg;
	int rc = 0;
	int nread;
	int server_fds[2];
	unsigned int num_fds = 2;

	msg = (struct cras_client_message *)buf;
	nread = cras_recv_with_fds(client->server_fd, buf, sizeof(buf),
				   server_fds, &num_fds);
	if (nread < (int)sizeof(msg->length) || (int)msg->length != nread)
		return -EIO;

	switch (msg->id) {
	case CRAS_CLIENT_CONNECTED: {
		struct cras_client_connected *cmsg =
			(struct cras_client_connected *)msg;
		if (num_fds != 1)
			return -EINVAL;
		rc = client_attach_shm(client, server_fds[0]);
		if (rc)
			return rc;
		client->id = cmsg->client_id;

		break;
	}
	case CRAS_CLIENT_STREAM_CONNECTED: {
		struct cras_client_stream_connected *cmsg =
			(struct cras_client_stream_connected *)msg;
		struct client_stream *stream =
			stream_from_id(client, cmsg->stream_id);
		if (stream == NULL)
			break;
		rc = stream_connected(stream, cmsg, server_fds, num_fds);
		if (rc < 0)
			stream->config->err_cb(stream->client,
					       stream->id,
					       rc,
					       stream->config->user_data);
		break;
	}
	case CRAS_CLIENT_AUDIO_DEBUG_INFO_READY:
		if (client->debug_info_callback)
			client->debug_info_callback(client);
		break;
	case CRAS_CLIENT_GET_HOTWORD_MODELS_READY: {
		struct cras_client_get_hotword_models_ready *cmsg =
			(struct cras_client_get_hotword_models_ready *)msg;
		cras_client_get_hotword_models_ready(client,
				(const char *)cmsg->hotword_models);
		break;
	}
	case CRAS_CLIENT_OUTPUT_VOLUME_CHANGED: {
		struct cras_client_volume_changed *cmsg =
			(struct cras_client_volume_changed *)msg;
		if (client->observer_ops.output_volume_changed)
			client->observer_ops.output_volume_changed(
					client->observer_context,
					cmsg->volume);
		break;
	}
	case CRAS_CLIENT_OUTPUT_MUTE_CHANGED: {
		struct cras_client_mute_changed *cmsg =
			(struct cras_client_mute_changed *)msg;
		if (client->observer_ops.output_mute_changed)
			client->observer_ops.output_mute_changed(
					client->observer_context,
					cmsg->muted,
					cmsg->user_muted,
					cmsg->mute_locked);
		break;
	}
	case CRAS_CLIENT_CAPTURE_GAIN_CHANGED: {
		struct cras_client_volume_changed *cmsg =
			(struct cras_client_volume_changed *)msg;
		if (client->observer_ops.capture_gain_changed)
			client->observer_ops.capture_gain_changed(
					client->observer_context,
					cmsg->volume);
		break;
	}
	case CRAS_CLIENT_CAPTURE_MUTE_CHANGED: {
		struct cras_client_mute_changed *cmsg =
			(struct cras_client_mute_changed *)msg;
		if (client->observer_ops.capture_mute_changed)
			client->observer_ops.capture_mute_changed(
					client->observer_context,
					cmsg->muted,
					cmsg->mute_locked);
		break;
	}
	case CRAS_CLIENT_NODES_CHANGED: {
		if (client->observer_ops.nodes_changed)
			client->observer_ops.nodes_changed(
					client->observer_context);
		break;
	}
	case CRAS_CLIENT_ACTIVE_NODE_CHANGED: {
		struct cras_client_active_node_changed *cmsg =
			(struct cras_client_active_node_changed *)msg;
		enum CRAS_STREAM_DIRECTION direction =
			(enum CRAS_STREAM_DIRECTION)cmsg->direction;
		if (client->observer_ops.active_node_changed)
			client->observer_ops.active_node_changed(
					client->observer_context,
					direction, cmsg->node_id);
		break;
	}
	case CRAS_CLIENT_OUTPUT_NODE_VOLUME_CHANGED: {
		struct cras_client_node_value_changed *cmsg =
			(struct cras_client_node_value_changed *)msg;
		if (client->observer_ops.output_node_volume_changed)
			client->observer_ops.output_node_volume_changed(
					client->observer_context,
					cmsg->node_id,
					cmsg->value);
		break;
	}
	case CRAS_CLIENT_NODE_LEFT_RIGHT_SWAPPED_CHANGED: {
		struct cras_client_node_value_changed *cmsg =
			(struct cras_client_node_value_changed *)msg;
		if (client->observer_ops.node_left_right_swapped_changed)
			client->observer_ops.node_left_right_swapped_changed(
					client->observer_context,
					cmsg->node_id,
					cmsg->value);
		break;
	}
	case CRAS_CLIENT_INPUT_NODE_GAIN_CHANGED: {
		struct cras_client_node_value_changed *cmsg =
			(struct cras_client_node_value_changed *)msg;
		if (client->observer_ops.input_node_gain_changed)
			client->observer_ops.input_node_gain_changed(
					client->observer_context,
					cmsg->node_id,
					cmsg->value);
		break;
	}
	case CRAS_CLIENT_NUM_ACTIVE_STREAMS_CHANGED: {
		struct cras_client_num_active_streams_changed *cmsg =
		    (struct cras_client_num_active_streams_changed *)msg;
		enum CRAS_STREAM_DIRECTION direction =
			(enum CRAS_STREAM_DIRECTION)cmsg->direction;
		if (client->observer_ops.num_active_streams_changed)
			client->observer_ops.num_active_streams_changed(
					client->observer_context,
					direction, cmsg->num_active_streams);
		break;
	}
	default:
		break;
	}

	return 0;
}

/* Handles messages from streams to this client. */
static int handle_stream_message(struct cras_client *client,
				 int poll_revents)
{
	struct stream_msg msg;
	int rc;

	if ((poll_revents & POLLIN) == 0)
		return 0;

	rc = read(client->stream_fds[0], &msg, sizeof(msg));
	if (rc < 0)
		syslog(LOG_ERR, "cras_client: Stream read failed %d\n", errno);
	/* The only reason a stream sends a message is if it needs to be
	 * removed. An error on read would mean the same thing so regardless of
	 * what gets us here, just remove the stream */
	client_thread_rm_stream(client, msg.stream_id);
	return 0;
}

/* Handles messages from users to this client. */
static int handle_command_message(struct cras_client *client,
				  int poll_revents)
{
	uint8_t buf[MAX_CMD_MSG_LEN];
	struct command_msg *msg = (struct command_msg *)buf;
	int rc, to_read;

	if ((poll_revents & POLLIN) == 0)
		return 0;

	rc = read(client->command_fds[0], buf, sizeof(msg->len));
	if (rc != sizeof(msg->len) || msg->len > MAX_CMD_MSG_LEN) {
		rc = -EIO;
		goto cmd_msg_complete;
	}
	to_read = msg->len - rc;
	rc = read(client->command_fds[0], &buf[0] + rc, to_read);
	if (rc != to_read) {
		rc = -EIO;
		goto cmd_msg_complete;
	}

	switch (msg->msg_id) {
	case CLIENT_STOP: {
		struct client_stream *s;

		/* Stop all playing streams */
		DL_FOREACH(client->streams, s)
			client_thread_rm_stream(client, s->id);

		/* And stop this client */
		client->thread.state = CRAS_THREAD_STOP;
		rc = 0;
		break;
	}
	case CLIENT_ADD_STREAM: {
		struct add_stream_command_message *add_msg =
			(struct add_stream_command_message *)msg;
		rc = client_thread_add_stream(client,
					      add_msg->stream,
					      add_msg->stream_id_out,
					      add_msg->dev_idx);
		break;
	}
	case CLIENT_REMOVE_STREAM:
		rc = client_thread_rm_stream(client, msg->stream_id);
		break;
	case CLIENT_SET_STREAM_VOLUME_SCALER: {
		struct set_stream_volume_command_message *vol_msg =
			(struct set_stream_volume_command_message *)msg;
		rc = client_thread_set_stream_volume(client,
						     vol_msg->header.stream_id,
						     vol_msg->volume_scaler);
		break;
	}
	case CLIENT_SERVER_CONNECT:
		rc = connect_to_server_wait(client, false);
		break;
	case CLIENT_SERVER_CONNECT_ASYNC:
		rc = server_connect(client);
		break;
	default:
		assert(0);
		break;
	}

cmd_msg_complete:
	/* Wake the waiting main thread with the result of the command. */
	if (write(client->command_reply_fds[1], &rc, sizeof(rc)) != sizeof(rc))
		return -EIO;
	return rc;
}

/*  This thread handles non audio sample communication with the audio server.
 *  The client program will call fucntions below to send messages to this thread
 *  to add or remove streams or change parameters.
 */
static void *client_thread(void *arg)
{
	struct cras_client *client = (struct cras_client *)arg;
	struct pollfd pollfds[4];
	int (*cbs[4])(struct cras_client *client, int poll_revents);
	unsigned int num_pollfds, i;
	int rc;

	if (arg == NULL)
		return (void *)-EINVAL;

	while (thread_is_running(&client->thread)) {
		num_pollfds = 0;

		rc = cras_file_wait_get_fd(client->sock_file_wait);
		if (rc >= 0) {
			cbs[num_pollfds] = sock_file_wait_dispatch;
			pollfds[num_pollfds].fd = rc;
			pollfds[num_pollfds].events = POLLIN;
			pollfds[num_pollfds].revents = 0;
			num_pollfds++;
		}
		else
			syslog(LOG_ERR, "file wait fd: %d", rc);
		if (client->server_fd >= 0) {
			cbs[num_pollfds] = server_fd_dispatch;
			server_fill_pollfd(client, &(pollfds[num_pollfds]));
			num_pollfds++;
		}
		if (client->command_fds[0] >= 0) {
			cbs[num_pollfds] = handle_command_message;
			pollfds[num_pollfds].fd = client->command_fds[0];
			pollfds[num_pollfds].events = POLLIN;
			pollfds[num_pollfds].revents = 0;
			num_pollfds++;
		}
		if (client->stream_fds[0] >= 0) {
			cbs[num_pollfds] = handle_stream_message;
			pollfds[num_pollfds].fd = client->stream_fds[0];
			pollfds[num_pollfds].events = POLLIN;
			pollfds[num_pollfds].revents = 0;
			num_pollfds++;
		}

		rc = poll(pollfds, num_pollfds, -1);
		if (rc <= 0)
			continue;

		for (i = 0; i < num_pollfds; i++) {
			/* Only do one at a time, since some messages may
			 * result in change to other fds. */
			if (pollfds[i].revents) {
				cbs[i](client, pollfds[i].revents);
				break;
			}
		}
	}

	/* close the command reply pipe. */
	close(client->command_reply_fds[1]);
	client->command_reply_fds[1] = -1;

	return NULL;
}

/* Sends a message to the client thread to complete an action requested by the
 * user.  Then waits for the action to complete and returns the result. */
static int send_command_message(struct cras_client *client,
				struct command_msg *msg)
{
	int rc, cmd_res;
	if (client == NULL || !thread_is_running(&client->thread))
		return -EINVAL;

	rc = write(client->command_fds[1], msg, msg->len);
	if (rc != (int)msg->len)
		return -EPIPE;

	/* Wait for command to complete. */
	rc = read(client->command_reply_fds[0], &cmd_res, sizeof(cmd_res));
	if (rc != sizeof(cmd_res))
		return -EPIPE;
	return cmd_res;
}

/* Send a simple message to the client thread that holds no data. */
static int send_simple_cmd_msg(struct cras_client *client,
			       cras_stream_id_t stream_id,
			       unsigned msg_id)
{
	struct command_msg msg;

	msg.len = sizeof(msg);
	msg.stream_id = stream_id;
	msg.msg_id = msg_id;

	return send_command_message(client, &msg);
}

/* Sends the set volume message to the client thread. */
static int send_stream_volume_command_msg(struct cras_client *client,
					  cras_stream_id_t stream_id,
					  float volume_scaler)
{
	struct set_stream_volume_command_message msg;

	msg.header.len = sizeof(msg);
	msg.header.stream_id = stream_id;
	msg.header.msg_id = CLIENT_SET_STREAM_VOLUME_SCALER;
	msg.volume_scaler = volume_scaler;

	return send_command_message(client, &msg.header);
}

/* Sends a message back to the client and returns the error code. */
static int write_message_to_server(struct cras_client *client,
				   const struct cras_server_message *msg)
{
	ssize_t write_rc = -EPIPE;

	if (client->server_fd_state == CRAS_SOCKET_STATE_CONNECTED ||
	    client->server_fd_state == CRAS_SOCKET_STATE_FIRST_MESSAGE) {
		write_rc = write(client->server_fd, msg, msg->length);
		if (write_rc < 0)
			write_rc = -errno;
	}

	if (write_rc != (ssize_t)msg->length &&
	    client->server_fd_state != CRAS_SOCKET_STATE_FIRST_MESSAGE)
		return -EPIPE;

	if (write_rc < 0)
		return write_rc;
	else if (write_rc != (ssize_t)msg->length)
		return -EIO;
	else
		return 0;
}

/*
 * Exported Client Interface
 */

int cras_client_create(struct cras_client **client)
{
	const char *sock_dir;
	size_t sock_file_size;
	int rc;
	struct client_int *client_int;
	pthread_condattr_t cond_attr;

	/* Ignore SIGPIPE while using this API. */
	signal(SIGPIPE, SIG_IGN);

	sock_dir = cras_config_get_system_socket_file_dir();
	if (!sock_dir)
		return -ENOMEM;

	client_int = (struct client_int *)calloc(1, sizeof(*client_int));
	if (!client_int)
		return -ENOMEM;
	*client = &client_int->client;
	(*client)->server_fd = -1;
	(*client)->id = -1;

	rc = pthread_rwlock_init(&client_int->server_state_rwlock, NULL);
	if (rc != 0) {
		syslog(LOG_ERR, "cras_client: Could not init state rwlock.");
		rc = -rc;
		goto free_client;
	}

	rc = pthread_mutex_init(&(*client)->stream_start_lock, NULL);
	if (rc != 0) {
		syslog(LOG_ERR, "cras_client: Could not init start lock.");
		rc = -rc;
		goto free_rwlock;
	}

	pthread_condattr_init(&cond_attr);
	pthread_condattr_setclock(&cond_attr, CLOCK_MONOTONIC);
	rc = pthread_cond_init(&(*client)->stream_start_cond, &cond_attr);
	pthread_condattr_destroy(&cond_attr);
	if (rc != 0) {
		syslog(LOG_ERR, "cras_client: Could not init start cond.");
		rc = -rc;
		goto free_lock;
	}

	(*client)->server_event_fd = eventfd(0, EFD_CLOEXEC|EFD_NONBLOCK);
	if ((*client)->server_event_fd < 0) {
		syslog(LOG_ERR, "cras_client: Could not setup server eventfd.");
		rc = -errno;
		goto free_cond;
	}

	sock_file_size = strlen(sock_dir) + strlen(CRAS_SOCKET_FILE) + 2;
	(*client)->sock_file = (const char *)malloc(sock_file_size);
	if (!(*client)->sock_file) {
		rc = -ENOMEM;
		goto free_error;
	}
	snprintf((char *)(*client)->sock_file, sock_file_size, "%s/%s", sock_dir,
		 CRAS_SOCKET_FILE);

	rc = cras_file_wait_create((*client)->sock_file,
				   CRAS_FILE_WAIT_FLAG_NONE,
				   sock_file_wait_callback, *client,
				   &(*client)->sock_file_wait);
	if (rc != 0 && rc != -ENOENT) {
		syslog(LOG_ERR, "cras_client: Could not setup watch for '%s'.",
		       (*client)->sock_file);
		goto free_error;
	}
	(*client)->sock_file_exists = (rc == 0);

	/* Pipes used by the main thread and the client thread to send commands
	 * and replies. */
	rc = pipe((*client)->command_fds);
	if (rc < 0)
		goto free_error;
	/* Pipe used to communicate between the client thread and the audio
	 * thread. */
	rc = pipe((*client)->stream_fds);
	if (rc < 0) {
		close((*client)->command_fds[0]);
		close((*client)->command_fds[1]);
		goto free_error;
	}
	(*client)->command_reply_fds[0] = -1;
	(*client)->command_reply_fds[1] = -1;

	return 0;
free_error:
	if ((*client)->server_event_fd >= 0)
		close((*client)->server_event_fd);
	cras_file_wait_destroy((*client)->sock_file_wait);
	free((void *)(*client)->sock_file);
free_cond:
	pthread_cond_destroy(&(*client)->stream_start_cond);
free_lock:
	pthread_mutex_destroy(&(*client)->stream_start_lock);
free_rwlock:
	pthread_rwlock_destroy(&client_int->server_state_rwlock);
free_client:
	*client = NULL;
	free(client_int);
	return rc;
}

void cras_client_destroy(struct cras_client *client)
{
	struct client_int *client_int;
	if (client == NULL)
		return;
	client_int = to_client_int(client);
	client->server_connection_cb = NULL;
	client->server_err_cb = NULL;
	cras_client_stop(client);
	server_disconnect(client);
	close(client->command_fds[0]);
	close(client->command_fds[1]);
	close(client->stream_fds[0]);
	close(client->stream_fds[1]);
	cras_file_wait_destroy(client->sock_file_wait);
	pthread_rwlock_destroy(&client_int->server_state_rwlock);
	free((void *)client->sock_file);
	free(client_int);
}

int cras_client_connect(struct cras_client *client)
{
	return connect_to_server(client, NULL, true);
}

int cras_client_connect_timeout(struct cras_client *client,
				unsigned int timeout_ms)
{
	return connect_to_server_wait_retry(client, timeout_ms, true);
}

int cras_client_connected_wait(struct cras_client *client)
{
	return send_simple_cmd_msg(client, 0, CLIENT_SERVER_CONNECT);
}

int cras_client_connect_async(struct cras_client *client)
{
	return send_simple_cmd_msg(client, 0, CLIENT_SERVER_CONNECT_ASYNC);
}

struct cras_stream_params *cras_client_stream_params_create(
		enum CRAS_STREAM_DIRECTION direction,
		size_t buffer_frames,
		size_t cb_threshold,
		size_t unused,
		enum CRAS_STREAM_TYPE stream_type,
		uint32_t flags,
		void *user_data,
		cras_playback_cb_t aud_cb,
		cras_error_cb_t err_cb,
		struct cras_audio_format *format)
{
	struct cras_stream_params *params;

	params = (struct cras_stream_params *)malloc(sizeof(*params));
	if (params == NULL)
		return NULL;

	params->direction = direction;
	params->buffer_frames = buffer_frames;
	params->cb_threshold = cb_threshold;

	params->stream_type = stream_type;
	params->flags = flags;
	params->user_data = user_data;
	params->aud_cb = aud_cb;
	params->unified_cb = 0;
	params->err_cb = err_cb;
	memcpy(&(params->format), format, sizeof(*format));
	return params;
}

struct cras_stream_params *cras_client_unified_params_create(
		enum CRAS_STREAM_DIRECTION direction,
		unsigned int block_size,
		enum CRAS_STREAM_TYPE stream_type,
		uint32_t flags,
		void *user_data,
		cras_unified_cb_t unified_cb,
		cras_error_cb_t err_cb,
		struct cras_audio_format *format)
{
	struct cras_stream_params *params;

	params = (struct cras_stream_params *)malloc(sizeof(*params));
	if (params == NULL)
		return NULL;

	params->direction = direction;
	params->buffer_frames = block_size * 2;
	params->cb_threshold = block_size;
	params->stream_type = stream_type;
	params->flags = flags;
	params->user_data = user_data;
	params->aud_cb = 0;
	params->unified_cb = unified_cb;
	params->err_cb = err_cb;
	memcpy(&(params->format), format, sizeof(*format));

	return params;
}

void cras_client_stream_params_destroy(struct cras_stream_params *params)
{
	free(params);
}

static inline int cras_client_send_add_stream_command_message(
		struct cras_client *client,
		uint32_t dev_idx,
		cras_stream_id_t *stream_id_out,
		struct cras_stream_params *config)
{
	struct add_stream_command_message cmd_msg;
	struct client_stream *stream;
	int rc = 0;

	if (client == NULL || config == NULL || stream_id_out == NULL)
		return -EINVAL;

	if (config->aud_cb == NULL && config->unified_cb == NULL)
		return -EINVAL;

	if (config->err_cb == NULL)
		return -EINVAL;

	stream = (struct client_stream *)calloc(1, sizeof(*stream));
	if (stream == NULL) {
		rc = -ENOMEM;
		goto add_failed;
	}
	stream->config = (struct cras_stream_params *)
			malloc(sizeof(*(stream->config)));
	if (stream->config == NULL) {
		rc = -ENOMEM;
		goto add_failed;
	}
	memcpy(stream->config, config, sizeof(*config));
	stream->aud_fd = -1;
	stream->wake_fds[0] = -1;
	stream->wake_fds[1] = -1;
	stream->direction = config->direction;
	stream->volume_scaler = 1.0;
	stream->flags = config->flags;

	cmd_msg.header.len = sizeof(cmd_msg);
	cmd_msg.header.msg_id = CLIENT_ADD_STREAM;
	cmd_msg.header.stream_id = stream->id;
	cmd_msg.stream = stream;
	cmd_msg.stream_id_out = stream_id_out;
	cmd_msg.dev_idx = dev_idx;
	rc = send_command_message(client, &cmd_msg.header);
	if (rc < 0) {
		syslog(LOG_ERR,
		       "cras_client: adding stream failed in thread %d", rc);
		goto add_failed;
	}

	return 0;

add_failed:
	if (stream) {
		if (stream->config)
			free(stream->config);
		free(stream);
	}
	return rc;
}

int cras_client_add_stream(struct cras_client *client,
			   cras_stream_id_t *stream_id_out,
			   struct cras_stream_params *config)
{
	return cras_client_send_add_stream_command_message(
			client,
			NO_DEVICE,
			stream_id_out,
			config);
}

int cras_client_add_pinned_stream(struct cras_client *client,
				  uint32_t dev_idx,
				  cras_stream_id_t *stream_id_out,
				  struct cras_stream_params *config)
{
	return cras_client_send_add_stream_command_message(
			client,
			dev_idx,
			stream_id_out,
			config);
}

int cras_client_rm_stream(struct cras_client *client,
			  cras_stream_id_t stream_id)
{
	if (client == NULL)
		return -EINVAL;

	return send_simple_cmd_msg(client, stream_id, CLIENT_REMOVE_STREAM);
}

int cras_client_set_stream_volume(struct cras_client *client,
				  cras_stream_id_t stream_id,
				  float volume_scaler)
{
	if (client == NULL)
		return -EINVAL;

	return send_stream_volume_command_msg(client, stream_id, volume_scaler);
}

int cras_client_set_system_volume(struct cras_client *client, size_t volume)
{
	struct cras_set_system_volume msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_system_volume(&msg, volume);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_system_capture_gain(struct cras_client *client, long gain)
{
	struct cras_set_system_capture_gain msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_system_capture_gain(&msg, gain);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_system_mute(struct cras_client *client, int mute)
{
	struct cras_set_system_mute msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_system_mute(&msg, mute);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_user_mute(struct cras_client *client, int mute)
{
	struct cras_set_system_mute msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_user_mute(&msg, mute);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_system_mute_locked(struct cras_client *client, int locked)
{
	struct cras_set_system_mute msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_system_mute_locked(&msg, locked);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_system_capture_mute(struct cras_client *client, int mute)
{
	struct cras_set_system_mute msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_system_capture_mute(&msg, mute);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_system_capture_mute_locked(struct cras_client *client,
					       int locked)
{
	struct cras_set_system_mute msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_system_capture_mute_locked(&msg, locked);
	return write_message_to_server(client, &msg.header);
}

size_t cras_client_get_system_volume(const struct cras_client *client)
{
	size_t volume;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	volume = client->server_state->volume;
	server_state_unlock(client, lock_rc);
	return volume;
}

long cras_client_get_system_capture_gain(const struct cras_client *client)
{
	long gain;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	gain = client->server_state->capture_gain;
	server_state_unlock(client, lock_rc);
	return gain;
}

int cras_client_get_system_muted(const struct cras_client *client)
{
	int muted;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	muted = client->server_state->mute;
	server_state_unlock(client, lock_rc);
	return muted;
}

int cras_client_get_user_muted(const struct cras_client *client)
{
	int muted;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	muted = client->server_state->user_mute;
	server_state_unlock(client, lock_rc);
	return muted;
}

int cras_client_get_system_capture_muted(const struct cras_client *client)
{
	int muted;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	muted = client->server_state->capture_mute;
	server_state_unlock(client, lock_rc);
	return muted;
}

long cras_client_get_system_min_volume(const struct cras_client *client)
{
	long min_volume;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	min_volume = client->server_state->min_volume_dBFS;
	server_state_unlock(client, lock_rc);
	return min_volume;
}

long cras_client_get_system_max_volume(const struct cras_client *client)
{
	long max_volume;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	max_volume = client->server_state->max_volume_dBFS;
	server_state_unlock(client, lock_rc);
	return max_volume;
}

long cras_client_get_system_min_capture_gain(const struct cras_client *client)
{
	long min_gain;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	min_gain = client->server_state->min_capture_gain;
	server_state_unlock(client, lock_rc);
	return min_gain;
}

long cras_client_get_system_max_capture_gain(const struct cras_client *client)
{
	long max_gain;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	max_gain = client->server_state->max_capture_gain;
	server_state_unlock(client, lock_rc);
	return max_gain;
}

const struct audio_debug_info *cras_client_get_audio_debug_info(
		const struct cras_client *client)
{
	const struct audio_debug_info *debug_info;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

	debug_info = &client->server_state->audio_debug_info;
	server_state_unlock(client, lock_rc);
	return debug_info;
}

unsigned cras_client_get_num_active_streams(const struct cras_client *client,
					    struct timespec *ts)
{
	unsigned num_streams, version, i;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return 0;

read_active_streams_again:
	version = begin_server_state_read(client->server_state);
	num_streams = 0;
	for (i = 0; i < CRAS_NUM_DIRECTIONS; i++)
		num_streams += client->server_state->num_active_streams[i];
	if (ts) {
		if (num_streams)
			clock_gettime(CLOCK_MONOTONIC_RAW, ts);
		else
			cras_timespec_to_timespec(ts,
				&client->server_state->last_active_stream_time);
	}
	if (end_server_state_read(client->server_state, version))
		goto read_active_streams_again;

	server_state_unlock(client, lock_rc);
	return num_streams;
}

int cras_client_run_thread(struct cras_client *client)
{
	int rc;

	if (client == NULL)
		return -EINVAL;
	if (thread_is_running(&client->thread))
		return 0;

	assert(client->command_reply_fds[0] == -1 &&
	       client->command_reply_fds[1] == -1);

	if (pipe(client->command_reply_fds) < 0)
		return -EIO;
	client->thread.state = CRAS_THREAD_RUNNING;
	rc = pthread_create(&client->thread.tid, NULL, client_thread, client);
	if (rc) {
		client->thread.state = CRAS_THREAD_STOP;
		return -rc;
	}

	return 0;
}

int cras_client_stop(struct cras_client *client)
{
	if (client == NULL)
		return -EINVAL;
	if (!thread_is_running(&client->thread))
		return 0;

	send_simple_cmd_msg(client, 0, CLIENT_STOP);
	pthread_join(client->thread.tid, NULL);

	/* The other end of the reply pipe is closed by the client thread, just
	 * clost the read end here. */
	close(client->command_reply_fds[0]);
	client->command_reply_fds[0] = -1;

	return 0;
}

void cras_client_set_server_error_cb(struct cras_client *client,
				     cras_server_error_cb_t err_cb,
				     void *user_arg)
{
	client->server_err_cb = err_cb;
	client->server_connection_user_arg = user_arg;
}

void cras_client_set_connection_status_cb(
		struct cras_client *client,
		cras_connection_status_cb_t connection_cb,
		void *user_arg)
{
	client->server_connection_cb = connection_cb;
	client->server_connection_user_arg = user_arg;
}

void cras_client_set_thread_priority_cb(struct cras_client *client,
					cras_thread_priority_cb_t cb)
{
	client->thread_priority_cb = cb;
}

int cras_client_get_output_devices(const struct cras_client *client,
				   struct cras_iodev_info *devs,
				   struct cras_ionode_info *nodes,
				   size_t *num_devs, size_t *num_nodes)
{
	const struct cras_server_state *state;
	unsigned avail_devs, avail_nodes, version;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return -EINVAL;
	state = client->server_state;

read_outputs_again:
	version = begin_server_state_read(state);
	avail_devs = MIN(*num_devs, state->num_output_devs);
	memcpy(devs, state->output_devs, avail_devs * sizeof(*devs));
	avail_nodes = MIN(*num_nodes, state->num_output_nodes);
	memcpy(nodes, state->output_nodes, avail_nodes * sizeof(*nodes));
	if (end_server_state_read(state, version))
		goto read_outputs_again;
	server_state_unlock(client, lock_rc);

	*num_devs = avail_devs;
	*num_nodes = avail_nodes;

	return 0;
}

int cras_client_get_input_devices(const struct cras_client *client,
				  struct cras_iodev_info *devs,
				  struct cras_ionode_info *nodes,
				  size_t *num_devs, size_t *num_nodes)
{
	const struct cras_server_state *state;
	unsigned avail_devs, avail_nodes, version;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (!client)
		return -EINVAL;
	state = client->server_state;

read_inputs_again:
	version = begin_server_state_read(state);
	avail_devs = MIN(*num_devs, state->num_input_devs);
	memcpy(devs, state->input_devs, avail_devs * sizeof(*devs));
	avail_nodes = MIN(*num_nodes, state->num_input_nodes);
	memcpy(nodes, state->input_nodes, avail_nodes * sizeof(*nodes));
	if (end_server_state_read(state, version))
		goto read_inputs_again;
	server_state_unlock(client, lock_rc);

	*num_devs = avail_devs;
	*num_nodes = avail_nodes;

	return 0;
}

int cras_client_get_attached_clients(const struct cras_client *client,
				     struct cras_attached_client_info *clients,
				     size_t max_clients)
{
	const struct cras_server_state *state;
	unsigned num, version;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return -EINVAL;
	state = client->server_state;

read_clients_again:
	version = begin_server_state_read(state);
	num = MIN(max_clients, state->num_attached_clients);
	memcpy(clients, state->client_info, num * sizeof(*clients));
	if (end_server_state_read(state, version))
		goto read_clients_again;
	server_state_unlock(client, lock_rc);

	return num;
}

/* Find an output ionode on an iodev with the matching name.
 *
 * Args:
 *    dev_name - The prefix of the iodev name.
 *    node_name - The prefix of the ionode name.
 *    dev_info - The information about the iodev will be returned here.
 *    node_info - The information about the ionode will be returned here.
 * Returns:
 *    0 if successful, -1 if the node cannot be found.
 */
static int cras_client_find_output_node(const struct cras_client *client,
					const char *dev_name,
					const char *node_name,
					struct cras_iodev_info *dev_info,
					struct cras_ionode_info *node_info)
{
	size_t ndevs, nnodes;
	struct cras_iodev_info *devs = NULL;
	struct cras_ionode_info *nodes = NULL;
	int rc = -1;
	unsigned i, j;

	if (!client || !dev_name || !node_name)
		goto quit;

	devs = (struct cras_iodev_info *)
			malloc(CRAS_MAX_IODEVS * sizeof(*devs));
	if (!devs)
		goto quit;

	nodes = (struct cras_ionode_info *)
			malloc(CRAS_MAX_IONODES * sizeof(*nodes));
	if (!nodes)
		goto quit;

	ndevs = CRAS_MAX_IODEVS;
	nnodes = CRAS_MAX_IONODES;
	rc = cras_client_get_output_devices(client, devs, nodes, &ndevs,
					    &nnodes);
	if (rc < 0)
		goto quit;

	for (i = 0; i < ndevs; i++)
		if (!strncmp(dev_name, devs[i].name, strlen(dev_name)))
			goto found_dev;
	rc = -1;
	goto quit;

found_dev:
	for (j = 0; j < nnodes; j++)
		if (nodes[j].iodev_idx == devs[i].idx &&
		    !strncmp(node_name, nodes[j].name, strlen(node_name)))
			goto found_node;
	rc = -1;
	goto quit;

found_node:
	*dev_info = devs[i];
	*node_info = nodes[j];
	rc = 0;

quit:
	free(devs);
	free(nodes);
	return rc;
}

int cras_client_get_node_by_id(const struct cras_client *client,
			       int input,
			       const cras_node_id_t node_id,
			       struct cras_ionode_info* node_info)
{
	size_t ndevs, nnodes;
	struct cras_iodev_info *devs = NULL;
	struct cras_ionode_info *nodes = NULL;
	int rc = -EINVAL;
	unsigned i;

	if (!client || !node_info) {
		rc = -EINVAL;
		goto quit;
	}

	devs = (struct cras_iodev_info *)
			malloc(CRAS_MAX_IODEVS * sizeof(*devs));
	if (!devs) {
		rc = -ENOMEM;
		goto quit;
	}

	nodes = (struct cras_ionode_info *)
			malloc(CRAS_MAX_IONODES * sizeof(*nodes));
	if (!nodes) {
		rc = -ENOMEM;
		goto quit;
	}

	ndevs = CRAS_MAX_IODEVS;
	nnodes = CRAS_MAX_IONODES;
	if (input)
		rc = cras_client_get_input_devices(client, devs, nodes,
						&ndevs, &nnodes);
	else
		rc = cras_client_get_output_devices(client, devs, nodes,
						&ndevs, &nnodes);
	if (rc < 0)
		goto quit;

	rc = -ENOENT;
	for (i = 0; i < nnodes; i++) {
		if (node_id == cras_make_node_id(nodes[i].iodev_idx,
						 nodes[i].ionode_idx)) {
			memcpy(node_info, &nodes[i], sizeof(*node_info));
			rc = 0;
			break;
		}
	}

quit:
	free(devs);
	free(nodes);
	return rc;
}

int cras_client_output_dev_plugged(const struct cras_client *client,
				   const char *name)
{
	struct cras_iodev_info dev_info;
	struct cras_ionode_info node_info = { 0 };

	if (cras_client_find_output_node(client, name, "Front Headphone Jack",
					 &dev_info, &node_info) < 0)
		return 0;

	return node_info.plugged;
}

int cras_client_set_node_attr(struct cras_client *client,
			      cras_node_id_t node_id,
			      enum ionode_attr attr, int value)
{
	struct cras_set_node_attr msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_node_attr(&msg, node_id, attr, value);
	return write_message_to_server(client, &msg.header);
}

int cras_client_select_node(struct cras_client *client,
			    enum CRAS_STREAM_DIRECTION direction,
			    cras_node_id_t node_id)
{
	struct cras_select_node msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_select_node(&msg, direction, node_id);
	return write_message_to_server(client, &msg.header);
}

int cras_client_add_active_node(struct cras_client *client,
				enum CRAS_STREAM_DIRECTION direction,
				cras_node_id_t node_id)
{
	struct cras_add_active_node msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_add_active_node(&msg, direction, node_id);
	return write_message_to_server(client, &msg.header);
}

int cras_client_rm_active_node(struct cras_client *client,
			       enum CRAS_STREAM_DIRECTION direction,
			       cras_node_id_t node_id)
{
	struct cras_rm_active_node msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_rm_active_node(&msg, direction, node_id);
	return write_message_to_server(client, &msg.header);
}

int cras_client_format_bytes_per_frame(struct cras_audio_format *fmt)
{
	if (fmt == NULL)
		return -EINVAL;

	return cras_get_format_bytes(fmt);
}

int cras_client_calc_playback_latency(const struct timespec *sample_time,
				      struct timespec *delay)
{
	struct timespec now;

	if (delay == NULL)
		return -EINVAL;

	clock_gettime(CLOCK_MONOTONIC_RAW, &now);

	/* for output return time until sample is played (t - now) */
	subtract_timespecs(sample_time, &now, delay);
	return 0;
}

int cras_client_calc_capture_latency(const struct timespec *sample_time,
				     struct timespec *delay)
{
	struct timespec now;

	if (delay == NULL)
		return -EINVAL;

	clock_gettime(CLOCK_MONOTONIC_RAW, &now);

	/* For input want time since sample read (now - t) */
	subtract_timespecs(&now, sample_time, delay);
	return 0;
}

int cras_client_reload_dsp(struct cras_client *client)
{
	struct cras_reload_dsp msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_reload_dsp(&msg);
	return write_message_to_server(client, &msg.header);
}

int cras_client_dump_dsp_info(struct cras_client *client)
{
	struct cras_dump_dsp_info msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_dump_dsp_info(&msg);
	return write_message_to_server(client, &msg.header);
}

int cras_client_update_audio_debug_info(
	struct cras_client *client,
	void (*debug_info_cb)(struct cras_client *))
{
	struct cras_dump_audio_thread msg;

	if (client == NULL)
		return -EINVAL;

	client->debug_info_callback = debug_info_cb;

	cras_fill_dump_audio_thread(&msg);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_node_volume(struct cras_client *client,
				cras_node_id_t node_id,
				uint8_t volume)
{
	struct cras_set_node_attr msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_node_attr(&msg, node_id, IONODE_ATTR_VOLUME, volume);
	return write_message_to_server(client, &msg.header);
}

int cras_client_swap_node_left_right(struct cras_client *client,
					cras_node_id_t node_id, int enable)
{
	struct cras_set_node_attr msg;

	if (client == NULL)
		return -EINVAL;

	cras_fill_set_node_attr(&msg, node_id, IONODE_ATTR_SWAP_LEFT_RIGHT,
				enable);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_node_capture_gain(struct cras_client *client,
				      cras_node_id_t node_id,
				      long gain)
{
	struct cras_set_node_attr msg;

	if (client == NULL)
		return -EINVAL;
	if (gain > INT_MAX || gain < INT_MIN)
		return -EINVAL;

	cras_fill_set_node_attr(&msg, node_id, IONODE_ATTR_CAPTURE_GAIN, gain);
	return write_message_to_server(client, &msg.header);
}

int cras_client_add_test_iodev(struct cras_client *client,
			       enum TEST_IODEV_TYPE type)
{
	struct cras_add_test_dev msg;

	cras_fill_add_test_dev(&msg, type);
	return write_message_to_server(client, &msg.header);
}

int cras_client_test_iodev_command(struct cras_client *client,
				   unsigned int iodev_idx,
				   enum CRAS_TEST_IODEV_CMD command,
				   unsigned int data_len,
				   const uint8_t *data)
{
	struct cras_test_dev_command *msg;
	int rc;

	msg = (struct cras_test_dev_command *)malloc(sizeof(*msg) + data_len);
	cras_fill_test_dev_command(msg, iodev_idx, command, data_len, data);
	rc = write_message_to_server(client, &msg->header);
	free(msg);
	return rc;
}

int cras_client_config_global_remix(struct cras_client *client,
				    unsigned num_channels,
				    float *coefficient)
{
	struct cras_config_global_remix *msg;
	int rc;

	msg = (struct cras_config_global_remix *)malloc(sizeof(*msg) +
			num_channels * num_channels * sizeof(*coefficient));
	cras_fill_config_global_remix_command(msg, num_channels,
					      coefficient,
					      num_channels * num_channels);
	rc = write_message_to_server(client, &msg->header);
	free(msg);
	return rc;
}

/* Return the index of the device used for listening to hotwords. */
int cras_client_get_first_dev_type_idx(const struct cras_client *client,
				       enum CRAS_NODE_TYPE type,
				       enum CRAS_STREAM_DIRECTION direction)
{
	const struct cras_server_state *state;
	unsigned int version;
	unsigned int i;
	const struct cras_ionode_info *node_list;
	unsigned int num_nodes;
	int lock_rc;

	lock_rc = server_state_rdlock(client);
	if (lock_rc)
		return -EINVAL;
	state = client->server_state;

read_nodes_again:
	version = begin_server_state_read(state);
	if (direction == CRAS_STREAM_OUTPUT) {
		node_list = state->output_nodes;
		num_nodes = state->num_output_nodes;
	} else {
		node_list = state->input_nodes;
		num_nodes = state->num_input_nodes;
	}
	for (i = 0; i < num_nodes; i++) {
		if ((enum CRAS_NODE_TYPE)node_list[i].type_enum == type) {
			int ret_idx = node_list[i].iodev_idx;
			server_state_unlock(client, lock_rc);
			return ret_idx;
		}
	}
	if (end_server_state_read(state, version))
		goto read_nodes_again;
	server_state_unlock(client, lock_rc);

	return -ENODEV;
}

int cras_client_set_suspend(struct cras_client *client, int suspend)
{
	struct cras_server_message msg;

	cras_fill_suspend_message(&msg, suspend);
	return write_message_to_server(client, &msg);
}

int cras_client_get_hotword_models(struct cras_client *client,
				     cras_node_id_t node_id,
				     get_hotword_models_cb_t cb)
{
	struct cras_get_hotword_models msg;

	if (!client)
		return -EINVAL;
	client->get_hotword_models_cb = cb;

	cras_fill_get_hotword_models_message(&msg, node_id);
	return write_message_to_server(client, &msg.header);
}

int cras_client_set_hotword_model(struct cras_client *client,
				  cras_node_id_t node_id,
				  const char *model_name)
{
	struct cras_set_hotword_model msg;

	cras_fill_set_hotword_model_message(&msg, node_id, model_name);
	return write_message_to_server(client, &msg.header);
}

void cras_client_set_state_change_callback_context(
		struct cras_client *client, void *context)
{
	if (!client)
		return;
	client->observer_context = context;
}

static int cras_send_register_notification(struct cras_client *client,
					   enum CRAS_CLIENT_MESSAGE_ID msg_id,
					   int do_register)
{
	struct cras_register_notification msg;
	int rc;

	/* This library automatically re-registers notifications when
	 * reconnecting, so we can ignore message send failure due to no
	 * connection. */
	cras_fill_register_notification_message(&msg, msg_id, do_register);
	rc = write_message_to_server(client, &msg.header);
	if (rc == -EPIPE)
		rc = 0;
	return rc;
}

int cras_client_set_output_volume_changed_callback(
		struct cras_client *client,
		cras_client_output_volume_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.output_volume_changed = cb;
	return cras_send_register_notification(
			client, CRAS_CLIENT_OUTPUT_VOLUME_CHANGED, cb != NULL);
}

int cras_client_set_output_mute_changed_callback(
		struct cras_client *client,
		cras_client_output_mute_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.output_mute_changed = cb;
	return cras_send_register_notification(
			client, CRAS_CLIENT_OUTPUT_MUTE_CHANGED, cb != NULL);
}

int cras_client_set_capture_gain_changed_callback(
		struct cras_client *client,
		cras_client_capture_gain_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.capture_gain_changed = cb;
	return cras_send_register_notification(
			client, CRAS_CLIENT_CAPTURE_GAIN_CHANGED, cb != NULL);
}

int cras_client_set_capture_mute_changed_callback(
		struct cras_client *client,
		cras_client_capture_mute_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.capture_mute_changed = cb;
	return cras_send_register_notification(
			client, CRAS_CLIENT_CAPTURE_MUTE_CHANGED, cb != NULL);
}

int cras_client_set_nodes_changed_callback(
		struct cras_client *client,
		cras_client_nodes_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.nodes_changed = cb;
	return cras_send_register_notification(
			client, CRAS_CLIENT_NODES_CHANGED, cb != NULL);
}

int cras_client_set_active_node_changed_callback(
		struct cras_client *client,
		cras_client_active_node_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.active_node_changed = cb;
	return cras_send_register_notification(
		   client, CRAS_CLIENT_ACTIVE_NODE_CHANGED, cb != NULL);
}

int cras_client_set_output_node_volume_changed_callback(
		struct cras_client *client,
		cras_client_output_node_volume_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.output_node_volume_changed = cb;
	return cras_send_register_notification(
		    client, CRAS_CLIENT_OUTPUT_NODE_VOLUME_CHANGED, cb != NULL);
}

int cras_client_set_node_left_right_swapped_changed_callback(
		struct cras_client *client,
		cras_client_node_left_right_swapped_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.node_left_right_swapped_changed = cb;
	return cras_send_register_notification(
	       client, CRAS_CLIENT_NODE_LEFT_RIGHT_SWAPPED_CHANGED, cb != NULL);
}

int cras_client_set_input_node_gain_changed_callback(
		struct cras_client *client,
		cras_client_input_node_gain_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.input_node_gain_changed = cb;
	return cras_send_register_notification(
		       client, CRAS_CLIENT_INPUT_NODE_GAIN_CHANGED, cb != NULL);
}

int cras_client_set_num_active_streams_changed_callback(
		struct cras_client *client,
		cras_client_num_active_streams_changed_callback cb)
{
	if (!client)
		return -EINVAL;
	client->observer_ops.num_active_streams_changed = cb;
	return cras_send_register_notification(
	      client, CRAS_CLIENT_NUM_ACTIVE_STREAMS_CHANGED, cb != NULL);
}

static int reregister_notifications(struct cras_client *client)
{
	int rc;

	if (client->observer_ops.output_volume_changed) {
		rc = cras_client_set_output_volume_changed_callback(
				client,
				client->observer_ops.output_volume_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.output_mute_changed) {
		rc = cras_client_set_output_mute_changed_callback(
				client,
				client->observer_ops.output_mute_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.capture_gain_changed) {
		rc = cras_client_set_capture_gain_changed_callback(
				client,
				client->observer_ops.capture_gain_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.capture_mute_changed) {
		rc = cras_client_set_capture_mute_changed_callback(
				client,
				client->observer_ops.capture_mute_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.nodes_changed) {
		rc = cras_client_set_nodes_changed_callback(
				client, client->observer_ops.nodes_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.active_node_changed) {
		rc = cras_client_set_active_node_changed_callback(
				client,
				client->observer_ops.active_node_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.output_node_volume_changed) {
		rc = cras_client_set_output_node_volume_changed_callback(
			    client,
			    client->observer_ops.output_node_volume_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.node_left_right_swapped_changed) {
		rc = cras_client_set_node_left_right_swapped_changed_callback(
			  client,
			  client->observer_ops.node_left_right_swapped_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.input_node_gain_changed) {
		rc = cras_client_set_input_node_gain_changed_callback(
				client,
				client->observer_ops.input_node_gain_changed);
		if (rc != 0)
			return rc;
	}
	if (client->observer_ops.num_active_streams_changed) {
		rc = cras_client_set_num_active_streams_changed_callback(
			       client,
			       client->observer_ops.num_active_streams_changed);
		if (rc != 0)
			return rc;
	}
	return 0;
}