multi-client support

.github/iwyu.imp

@@ -43,4 +43,6 @@
 
 	{ include: [ '<spandsp/plc.h>', private, '<spandsp.h>', public ] },
 
+	{ include: [ '<bits/types/struct_itimerspec.h>', private, '<sys/timerfd.h>', public ] },
+
 ]

.github/spellcheck-wordlist.txt

@@ -157,6 +157,8 @@ BTRH
 BTT
 bttransport
 btusb
+# aspell considers PIPE_BUF to be 2 words :(
+BUF
 CCE
 CIEV
 CIND
@@ -183,6 +185,7 @@ ENODEV
 EP
 EPIPE
 EPMR
+epoll
 EQMID
 errno
 FB

doc/bluealsa.8.rst

@@ -58,6 +58,12 @@ OPTIONS
     Without this option, **bluealsa** registers itself as an "org.bluealsa"
     D-Bus service.  For more information see the EXAMPLES_ below.
 
+-M, --multi-client
+    Permit multiple clients to connect to the same PCM stream.
+    Without this option, only one client can connect to a PCM.
+    With this option, for playback clients, the streams are mixed together;
+    for capture each client receives a copy of the stream.
+
 -i hciX, --device=hciX
     HCI device to use. Can be specified multiple times to select more than one
     HCI.  Because HCI numbering can change after a system reboot, this option

src/Makefile.am

@@ -35,6 +35,9 @@ bluealsa_SOURCES = \
 	ba-transport-pcm.c \
 	bluealsa-dbus.c \
 	bluealsa-iface.xml \
+	bluealsa-mix-buffer.c \
+	bluealsa-pcm-client.c \
+	bluealsa-pcm-multi.c \
 	bluez.c \
 	bluez-iface.xml \
 	codec-sbc.c \

src/a2dp-aac.c

@@ -30,6 +30,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-pcm-multi.h"
 #include "io.h"
 #include "rtp.h"
 #include "utils.h"
@@ -288,6 +289,11 @@ void *a2dp_aac_enc_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	rtp_header_t *rtp_header;
 	/* initialize RTP header and get anchor for payload */
 	uint8_t *rtp_payload = rtp_a2dp_init(bt.data, &rtp_header, NULL, 0);
@@ -468,6 +474,11 @@ void *a2dp_aac_dec_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	struct rtp_state rtp = { .synced = false };
 	/* RTP clock frequency equal to 90kHz */
 	rtp_state_init(&rtp, samplerate, 90000);

src/a2dp-aptx-hd.c

@@ -26,6 +26,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-pcm-multi.h"
 #include "codec-aptx.h"
 #include "io.h"
 #include "rtp.h"
@@ -138,6 +139,11 @@ void *a2dp_aptx_hd_enc_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	rtp_header_t *rtp_header;
 	/* initialize RTP header and get anchor for payload */
 	uint8_t *rtp_payload = rtp_a2dp_init(bt.data, &rtp_header, NULL, 0);
@@ -271,6 +277,11 @@ void *a2dp_aptx_hd_dec_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	struct rtp_state rtp = { .synced = false };
 	/* RTP clock frequency equal to audio samplerate */
 	rtp_state_init(&rtp, samplerate, samplerate);

src/a2dp-aptx.c

@@ -25,6 +25,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-pcm-multi.h"
 #include "codec-aptx.h"
 #include "io.h"
 #include "shared/a2dp-codecs.h"
@@ -135,6 +136,11 @@ void *a2dp_aptx_enc_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	debug_transport_pcm_thread_loop(t_pcm, "START");
 	for (ba_transport_pcm_state_set_running(t_pcm);;) {
 
@@ -249,6 +255,11 @@ void *a2dp_aptx_dec_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	debug_transport_pcm_thread_loop(t_pcm, "START");
 	for (ba_transport_pcm_state_set_running(t_pcm);;) {
 

src/a2dp-faststream.c

@@ -24,6 +24,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-pcm-multi.h"
 #include "codec-sbc.h"
 #include "io.h"
 #include "shared/a2dp-codecs.h"
@@ -150,6 +151,11 @@ void *a2dp_faststream_enc_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	debug_transport_pcm_thread_loop(t_pcm, "START");
 	for (ba_transport_pcm_state_set_running(t_pcm);;) {
 
@@ -270,6 +276,11 @@ void *a2dp_faststream_dec_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	debug_transport_pcm_thread_loop(t_pcm, "START");
 	for (ba_transport_pcm_state_set_running(t_pcm);;) {
 

src/a2dp-ldac.c

@@ -27,6 +27,7 @@
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
 #include "ba-config.h"
+#include "bluealsa-pcm-multi.h"
 #include "io.h"
 #include "rtp.h"
 #include "utils.h"
@@ -166,6 +167,11 @@ void *a2dp_ldac_enc_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	rtp_header_t *rtp_header;
 	rtp_media_header_t *rtp_media_header;
 	/* initialize RTP headers and get anchor for payload */
@@ -323,6 +329,11 @@ void *a2dp_ldac_dec_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	struct rtp_state rtp = { .synced = false };
 	/* RTP clock frequency equal to audio samplerate */
 	rtp_state_init(&rtp, samplerate, samplerate);

src/a2dp-mpeg.c

@@ -35,6 +35,7 @@
 #include "ba-config.h"
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
+#include "bluealsa-pcm-multi.h"
 #include "io.h"
 #include "rtp.h"
 #include "utils.h"
@@ -226,6 +227,11 @@ void *a2dp_mp3_enc_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	rtp_header_t *rtp_header;
 	rtp_mpeg_audio_header_t *rtp_mpeg_audio_header;
 	/* initialize RTP headers and get anchor for payload */
@@ -411,6 +417,11 @@ void *a2dp_mpeg_dec_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	struct rtp_state rtp = { .synced = false };
 	/* RTP clock frequency equal to 90kHz */
 	rtp_state_init(&rtp, samplerate, 90000);

src/a2dp-sbc.c

@@ -29,6 +29,7 @@
 #include "ba-transport.h"
 #include "ba-transport-pcm.h"
 #include "ba-config.h"
+#include "bluealsa-pcm-multi.h"
 #include "codec-sbc.h"
 #include "io.h"
 #include "rtp.h"
@@ -177,6 +178,11 @@ void *a2dp_sbc_enc_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	rtp_header_t *rtp_header;
 	rtp_media_header_t *rtp_media_header;
 
@@ -320,6 +326,11 @@ void *a2dp_sbc_dec_thread(struct ba_transport_pcm *t_pcm) {
 		goto fail_ffb;
 	}
 
+	/* start multi client thread if required. */
+	if (t_pcm->multi &&
+			!bluealsa_pcm_multi_init(t_pcm->multi, pcm.nmemb))
+		goto fail_ffb;
+
 	struct rtp_state rtp = { .synced = false };
 	/* RTP clock frequency equal to audio samplerate */
 	rtp_state_init(&rtp, samplerate, samplerate);

src/asound/bluealsa-pcm.c

@@ -577,6 +577,10 @@ static int bluealsa_hw_params(snd_pcm_ioplug_t *io, snd_pcm_hw_params_t *params)
 		return ret;
 
 	if (pcm->ba_pcm.channels != channels || pcm->ba_pcm.sampling != sampling) {
+		if (pcm->ba_pcm.running) {
+			SNDERR("Couldn't change BlueALSA PCM configuration");
+			return -EINVAL;
+		}
 		debug2("Changing BlueALSA PCM configuration: %u ch, %u Hz -> %u ch, %u Hz",
 				pcm->ba_pcm.channels, pcm->ba_pcm.sampling, channels, sampling);
 
@@ -1330,6 +1334,21 @@ static int bluealsa_set_hw_constraint(struct bluealsa_pcm *pcm) {
 	unsigned int list[ARRAYSIZE(codec->sampling)];
 	unsigned int n;
 
+	/* If the PCM is already running, we must not change the codec config as
+	* that would terminate the stream for the running client */
+	if (pcm->ba_pcm.running) {
+		if ((err = snd_pcm_ioplug_set_param_minmax(io,
+					SND_PCM_IOPLUG_HW_CHANNELS, pcm->ba_pcm.channels,
+					pcm->ba_pcm.channels)) < 0)
+			return err;
+
+		if ((err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_RATE,
+					pcm->ba_pcm.sampling, pcm->ba_pcm.sampling)) < 0)
+			return err;
+
+		return 0;
+	}
+
 	/* Populate the list of supported channels and sampling rates. For codecs
 	 * with fixed configuration, the list will contain only one element. For
 	 * other codecs, the list might contain all supported configurations. */
@@ -1557,26 +1576,39 @@ SND_PCM_PLUGIN_DEFINE_FUNC(bluealsa) {
 		 * sampling rate and channels for HW constraints. */
 		const char *canonical = ba_dbus_pcm_codec_get_canonical_name(codec_name);
 		const bool name_changed = strcmp(canonical, pcm->ba_pcm.codec.name) != 0;
-		if (name_changed && !ba_dbus_pcm_select_codec(&pcm->dbus_ctx, pcm->ba_pcm.pcm_path,
-					canonical, NULL, 0, 0, 0, BA_PCM_SELECT_CODEC_FLAG_NONE, &err)) {
-			SNDERR("Couldn't select BlueALSA PCM codec: %s", err.message);
-			dbus_error_free(&err);
+
+		if (pcm->ba_pcm.running) {
+			if (name_changed)
+				SNDERR("Couldn't change BlueALSA PCM codec");
+			else if (codec_config_len > 0 && (
+						pcm->ba_pcm.codec.data_len != codec_config_len ||
+						memcmp(pcm->ba_pcm.codec.data, codec_config, codec_config_len) != 0))
+				SNDERR("Couldn't change BlueALSA PCM codec configuration");
 		}
 		else {
+			if (name_changed && !ba_dbus_pcm_select_codec(&pcm->dbus_ctx, pcm->ba_pcm.pcm_path,
+						canonical, NULL, 0, 0, 0, BA_PCM_SELECT_CODEC_FLAG_NONE, &err)) {
+				SNDERR("Couldn't select BlueALSA PCM codec: %s", err.message);
+				dbus_error_free(&err);
+			}
+			else {
 
-			memcpy(pcm->ba_pcm_codec_config, codec_config, codec_config_len);
-			pcm->ba_pcm_codec_config_len = codec_config_len;
+				memcpy(pcm->ba_pcm_codec_config, codec_config, codec_config_len);
+				pcm->ba_pcm_codec_config_len = codec_config_len;
+
+				/* Changing the codec may change the audio format, sampling rate
+				 * and/or channels. We need to refresh our cache of PCM
+				 * properties. */
+				if (name_changed &&
+						!ba_dbus_pcm_get(&pcm->dbus_ctx, &ba_addr, ba_profile,
+							stream == SND_PCM_STREAM_PLAYBACK ? BA_PCM_MODE_SINK : BA_PCM_MODE_SOURCE,
+							&pcm->ba_pcm, &err)) {
+					SNDERR("Couldn't get BlueALSA PCM: %s", err.message);
+					ret = -dbus_error_to_errno(&err);
+					goto fail;
+				}
 
-			/* Changing the codec may change the audio format, sampling rate and/or
-			 * channels. We need to refresh our cache of PCM properties. */
-			if (name_changed && !ba_dbus_pcm_get(&pcm->dbus_ctx, &ba_addr, ba_profile,
-						stream == SND_PCM_STREAM_PLAYBACK ? BA_PCM_MODE_SINK : BA_PCM_MODE_SOURCE,
-						&pcm->ba_pcm, &err)) {
-				SNDERR("Couldn't get BlueALSA PCM: %s", err.message);
-				ret = -dbus_error_to_errno(&err);
-				goto fail;
 			}
-
 		}
 	}
 

src/ba-config.c

@@ -41,6 +41,8 @@ struct ba_config config = {
 
 	.disable_realtek_usb_fix = false,
 
+	.multi_enabled = false,
+
 	/* CVSD is a mandatory codec */
 	.hfp.codecs.cvsd = true,
 #if ENABLE_MSBC

src/ba-config.h

@@ -75,6 +75,9 @@ struct ba_config {
 	/* disable alt-3 MTU for mSBC with Realtek USB adapters */
 	bool disable_realtek_usb_fix;
 
+	/* Is multi client support enabled? */
+	bool multi_enabled;
+
 	struct {
 
 		/* available HFP codecs */