Simple process communication

1 files changed, 242 insertions, 2 deletions

diff --git a/audio/ctl_bluetooth.c b/audio/ctl_bluetooth.c
index 511a1b24..4e55058e 100644
--- a/audio/ctl_bluetooth.c
+++ b/audio/ctl_bluetooth.c
@@ -25,14 +25,254 @@
 #include <config.h>
 #endif
 
+#include <sys/socket.h>
+#include <sys/un.h>
+
 #include <alsa/asoundlib.h>
 #include <alsa/control_external.h>
 
+#ifndef UNIX_PATH_MAX
+#define UNIX_PATH_MAX 108
+#endif
+
+#define DBG(fmt, arg...)  printf("DEBUG: %s: " fmt "\n" , __FUNCTION__ , ## arg)
+
+#define SOCKET_NAME "/org/bluez/audio"
+
+#define BLUETOOTH_MINVOL 0
+#define BLUETOOTH_MAXVOL 15
+
+struct bluetooth_data {
+	snd_ctl_ext_t ext;
+	int sock;
+};
+
+enum {
+	BLUETOOTH_PLAYBACK,
+	BLUETOOTH_CAPTURE,
+};
+
+static const char *vol_devices[2] = {
+	[BLUETOOTH_PLAYBACK]	= "Playback volume",
+	[BLUETOOTH_CAPTURE]	= "Capture volume",
+};
+
+static void bluetooth_close(snd_ctl_ext_t *ext)
+{
+	struct bluetooth_data *data = ext->private_data;
+
+	DBG("ext %p", ext);
+
+	close(data->sock);
+
+	free(data);
+}
+
+static int bluetooth_elem_count(snd_ctl_ext_t *ext)
+{
+	DBG("ext %p", ext);
+
+	return 2;
+}
+
+static int bluetooth_elem_list(snd_ctl_ext_t *ext,
+				unsigned int offset, snd_ctl_elem_id_t *id)
+{
+	DBG("ext %p offset %d id %p", ext, offset, id);
+
+	snd_ctl_elem_id_set_interface(id, SND_CTL_ELEM_IFACE_MIXER);
+
+	if (offset > 1)
+		return -EINVAL;
+
+	snd_ctl_elem_id_set_name(id, vol_devices[offset]);
+
+	return 0;
+}
+
+static snd_ctl_ext_key_t bluetooth_find_elem(snd_ctl_ext_t *ext,
+						const snd_ctl_elem_id_t *id)
+{
+	const char *name = snd_ctl_elem_id_get_name(id);
+	int i;
+
+	DBG("ext %p id %p name '%s'", ext, id, name);
+
+	for (i = 0; i < 2; i++)
+		if (strcmp(name, vol_devices[i]) == 0)
+			return i;
+
+	return SND_CTL_EXT_KEY_NOT_FOUND;
+}
+
+static int bluetooth_get_attribute(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
+			int *type, unsigned int *acc, unsigned int *count)
+{
+	DBG("ext %p key %td", ext, key);
+
+	*type  = SND_CTL_ELEM_TYPE_INTEGER;
+	*acc   = SND_CTL_EXT_ACCESS_READWRITE;
+	*count = 1;
+
+	return 0;
+}
+
+static int bluetooth_get_integer_info(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
+					long *imin, long *imax, long *istep)
+{
+	DBG("ext %p key %td", ext, key);
+
+	*istep = 1;
+	*imin  = BLUETOOTH_MINVOL;
+	*imax  = BLUETOOTH_MAXVOL;
+
+	return 0;
+}
+
+static int bluetooth_read_integer(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
+								long *value)
+{
+	struct bluetooth_data *data = ext->private_data;
+	unsigned char buf[] = { 0x00, 0x00 };
+	int len;
+
+	DBG("ext %p key %td", ext, key);
+
+	len = write(data->sock, buf, sizeof(buf));
+
+	*value = 0;
+
+	return 0;
+}
+
+static int bluetooth_write_integer(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
+								long *value)
+{
+	struct bluetooth_data *data = ext->private_data;
+	unsigned char buf[] = { 0xff, 0xff };
+	int len;
+
+	DBG("ext %p key %td", ext, key);
+
+	len = write(data->sock, buf, sizeof(buf));
+
+	return 0;
+}
+
+static int bluetooth_read_event(snd_ctl_ext_t *ext, snd_ctl_elem_id_t *id,
+						unsigned int *event_mask)
+{
+	struct bluetooth_data *data = ext->private_data;
+	unsigned char buf[128];
+	int len;
+
+	//DBG("ext %p id %p", ext, id);
+
+	len = recv(data->sock, buf, sizeof(buf), MSG_DONTWAIT);
+
+	return 0;
+}
+
+static snd_ctl_ext_callback_t bluetooth_callback = {
+	.close			= bluetooth_close,
+	.elem_count		= bluetooth_elem_count,
+	.elem_list		= bluetooth_elem_list,
+	.find_elem		= bluetooth_find_elem,
+	.get_attribute		= bluetooth_get_attribute,
+	.get_integer_info	= bluetooth_get_integer_info,
+	.read_integer		= bluetooth_read_integer,
+	.write_integer		= bluetooth_write_integer,
+	.read_event		= bluetooth_read_event,
+};
+
 SND_CTL_PLUGIN_DEFINE_FUNC(bluetooth)
 {
-	printf("Bluetooth control plugin\n");
+	snd_config_iterator_t iter, next;
+	struct bluetooth_data *data;
+	struct sockaddr_un addr;
+	unsigned int id;
+	int sk, err;
+
+	DBG("");
+
+	snd_config_for_each(iter, next, conf) {
+		snd_config_t *n = snd_config_iterator_entry(iter);
+		const char *id;
+
+		if (snd_config_get_id(n, &id) < 0)
+			continue;
+
+		if (strcmp(id, "comment") == 0 || strcmp(id, "type") == 0)
+			continue;
+
+		SNDERR("Unknown field %s", id);
+
+		return -EINVAL;
+	}
+
+	id = abs(getpid() * rand());
+
+	sk = socket(PF_LOCAL, SOCK_DGRAM, 0);
+	if (sk < 0) {
+		SNDERR("Can't open socket");
+		return -errno;
+	}
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sun_family = AF_UNIX;
+	snprintf(addr.sun_path + 1, UNIX_PATH_MAX - 2, "%s/%d", SOCKET_NAME, id);
+
+	if (bind(sk, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		SNDERR("Can't bind socket");
+		close(sk);
+		return -errno;
+	}
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sun_family = AF_UNIX;
+	snprintf(addr.sun_path + 1, UNIX_PATH_MAX - 2, "%s", SOCKET_NAME);
+
+	if (connect(sk, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		SNDERR("Can't connect socket");
+		close(sk);
+		return -errno;
+	}
+
+	data = malloc(sizeof(*data));
+	if (!data) {
+		close(sk);
+		return -ENOMEM;
+	}
+
+	memset(data, 0, sizeof(*data));
+
+	data->sock = sk;
+
+	data->ext.version = SND_CTL_EXT_VERSION;
+	data->ext.card_idx = -1;
+
+	strncpy(data->ext.id, "bluetooth", sizeof(data->ext.id) - 1);
+	strncpy(data->ext.driver, "Bluetooth-Audio", sizeof(data->ext.driver) - 1);
+	strncpy(data->ext.name, "Bluetooth Audio", sizeof(data->ext.name) - 1);
+	strncpy(data->ext.longname, "Bluetooth Audio", sizeof(data->ext.longname) - 1);
+	strncpy(data->ext.mixername, "Bluetooth Audio", sizeof(data->ext.mixername) - 1);
+
+	data->ext.callback = &bluetooth_callback;
+	data->ext.poll_fd = sk;
+	data->ext.private_data = data;
+
+	err = snd_ctl_ext_create(&data->ext, name, mode);
+	if (err < 0)
+		goto error;
+
+	*handlep = data->ext.handle;
+
+	return 0;
+
+error:
+	free(data);
 
-	return -EIO;
+	return err;
 }
 
 SND_CTL_PLUGIN_SYMBOL(bluetooth);