android/audio: Add listener thread on the Audio HAL socket

This patch add thread which is reponsible for listen on audio HAL
socket, open a2dp endpoint(s) and maintain socket.
When bluetooth daemon goes down, HAL audio plugin starts to listen on
Audio HAL socket again.

android/Makefile.am

@@ -112,7 +112,8 @@ android_android_tester_LDFLAGS = -pthread
 
 noinst_LTLIBRARIES += android/libaudio-internal.la
 
-android_libaudio_internal_la_SOURCES = android/hal-audio.c \
+android_libaudio_internal_la_SOURCES = androdid/audio-msg.h \
+					android/hal-audio.c \
 					android/hardware/audio.h \
 					android/hardware/audio_effect.h \
 					android/hardware/hardware.h \
@@ -120,6 +121,8 @@ android_libaudio_internal_la_SOURCES = android/hal-audio.c \
 
 android_libaudio_internal_la_CFLAGS = -I$(srcdir)/android
 
+android_libaudio_internal_la_LDFLAGS = -pthread
+
 endif
 
 EXTRA_DIST += android/Android.mk android/hal-ipc-api.txt android/README \

android/hal-audio.c

@@ -16,15 +16,27 @@
  */
 
 #include <errno.h>
+#include <pthread.h>
+#include <poll.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
 
 #include <hardware/audio.h>
 #include <hardware/hardware.h>
 
+#include "audio-msg.h"
 #include "hal-log.h"
 
+static int audio_sk = -1;
+static bool close_thread = false;
+
+static pthread_t ipc_th = 0;
+static pthread_mutex_t close_mutex = PTHREAD_MUTEX_INITIALIZER;
+
 struct a2dp_audio_dev {
 	struct audio_hw_device dev;
 	struct audio_stream_out *out;
@@ -384,15 +396,116 @@ static int audio_dump(const audio_hw_device_t *device, int fd)
 
 static int audio_close(hw_device_t *device)
 {
+	struct a2dp_audio_dev *a2dp_dev = (struct a2dp_audio_dev *)device;
+
 	DBG("");
-	free(device);
+
+	pthread_mutex_lock(&close_mutex);
+	shutdown(audio_sk, SHUT_RDWR);
+	close_thread = true;
+	pthread_mutex_unlock(&close_mutex);
+
+	pthread_join(ipc_th, NULL);
+
+	free(a2dp_dev);
 	return 0;
 }
 
+static bool create_audio_ipc(void)
+{
+	struct sockaddr_un addr;
+	int err;
+	int sk;
+
+	DBG("");
+
+	sk = socket(PF_LOCAL, SOCK_SEQPACKET, 0);
+	if (sk < 0) {
+		err = errno;
+		error("Failed to create socket: %d (%s)", err, strerror(err));
+		return false;
+	}
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sun_family = AF_UNIX;
+
+	memcpy(addr.sun_path, BLUEZ_AUDIO_SK_PATH,
+					sizeof(BLUEZ_AUDIO_SK_PATH));
+
+	if (bind(sk, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		err = errno;
+		error("Failed to bind socket: %d (%s)", err, strerror(err));
+		goto failed;
+	}
+
+	if (listen(sk, 1) < 0) {
+		err = errno;
+		error("Failed to listen on the socket: %d (%s)", err,
+								strerror(err));
+		goto failed;
+	}
+
+	audio_sk = accept(sk, NULL, NULL);
+	if (audio_sk < 0) {
+		err = errno;
+		error("Failed to accept socket: %d (%s)", err, strerror(err));
+		goto failed;
+	}
+
+	close(sk);
+	return true;
+
+failed:
+	close(sk);
+	return false;
+}
+
+static void *ipc_handler(void *data)
+{
+	bool done = false;
+	struct pollfd pfd;
+
+	DBG("");
+
+	while (!done) {
+		if(!create_audio_ipc()) {
+			error("Failed to create listening socket");
+			sleep(1);
+			continue;
+		}
+
+		DBG("Audio IPC: Connected");
+
+		/* TODO: Register ENDPOINT here */
+
+		memset(&pfd, 0, sizeof(pfd));
+		pfd.fd = audio_sk;
+		pfd.events = POLLHUP | POLLERR | POLLNVAL;
+
+		/* Check if socket is still alive. Empty while loop.*/
+		while (poll(&pfd, 1, -1) < 0 && errno == EINTR);
+
+		if (pfd.revents & (POLLHUP | POLLERR | POLLNVAL)) {
+			info("Audio HAL: Socket closed");
+			audio_sk = -1;
+		}
+
+		/*Check if audio_dev is closed */
+		pthread_mutex_lock(&close_mutex);
+		done = close_thread;
+		close_thread = false;
+		pthread_mutex_unlock(&close_mutex);
+	}
+
+	info("Closing bluetooth_watcher thread");
+	return NULL;
+}
+
 static int audio_open(const hw_module_t *module, const char *name,
 							hw_device_t **device)
 {
 	struct a2dp_audio_dev *a2dp_dev;
+	int err;
 
 	DBG("");
 
@@ -430,6 +543,14 @@ static int audio_open(const hw_module_t *module, const char *name,
 	 * audio_hw_device. We will rely on this later in the code.*/
 	*device = &a2dp_dev->dev.common;
 
+	err = pthread_create(&ipc_th, NULL, ipc_handler, NULL);
+	if (err < 0) {
+		ipc_th = 0;
+		error("Failed to start Audio IPC thread: %d (%s)",
+							-err, strerror(-err));
+		return (-err);
+	}
+
 	return 0;
 }