meta-pipewire: add recipe to build the bluez-alsa-pipewire gstreamer helper

Unfortunately, the bluez-alsa PCM plugin does not work correctly
when it is used through pipewire (or gstreamer, or anywhere really...).
For this reason I have built a helper client that uses GStreamer
to glue together the bluez-alsa sockets with pipewire.

This helper is implemented as a patch to bluez-alsa so that it can
use its internal private API. In the future this needs some re-thinking

The helper is meant to run in the background as a service and it will
create the appropriate streams in pipewire when it detects a new
device on the bluealsa d-bus interface. Currently it only supports
a2dp-sink and hfp modes (i.e. media player from a phone + calls).
Bluetooth speakers need further policy work in wireplumber that is
too complex to support on the current halibut version of
pipewire/wireplumber.

Bug-AGL: SPEC-2792

Change-Id: I369b40eb1cf6d940ac233fff18605f400bce3628
Signed-off-by: George Kiagiadakis <george.kiagiadakis@collabora.com>

4 files changed, 518 insertions, 0 deletions

diff --git a/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa/0001-utils-add-a-gstreamer-helper-application-for-interco.patch b/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa/0001-utils-add-a-gstreamer-helper-application-for-interco.patch
new file mode 100644
index 00000000..37c03218
--- /dev/null
+++ b/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa/0001-utils-add-a-gstreamer-helper-application-for-interco.patch
@@ -0,0 +1,464 @@
+From 33555a493af67f3acc2129764a1b093aec6254d8 Mon Sep 17 00:00:00 2001
+From: George Kiagiadakis <george.kiagiadakis@collabora.com>
+Date: Fri, 4 Oct 2019 20:51:24 +0300
+Subject: [PATCH] utils: add a gstreamer helper application for interconnection
+ with pipewire
+
+Unfortunately, the bluez-alsa PCM plugin does not work correctly
+when it is used through pipewire (or gstreamer, or anywhere really...).
+
+Thanfully, the bluez-alsa PCM plugin is only a simple client that
+reads/writes on a file descriptor that was opened by bluealsa.
+This allows us to use bluealsa without the PCM plugin, just like it
+is done in the aplay.c util.
+
+This one uses GStreamer to implement the plumbing between pipewire
+and the file descriptor. On the reading side we are also doing some
+tricks to ensure a smooth stream, which is not the case for the
+stream that is coming out of bluealsa.
+
+This helper is implemented as a patch to bluez-alsa so that it can
+use its internal private API. In the future this needs some re-thinking.
+
+Upstream-Status: Inappropriate
+---
+ configure.ac       |   7 +
+ utils/Makefile.am  |  20 +++
+ utils/gst-helper.c | 379 +++++++++++++++++++++++++++++++++++++++++++++
+ 3 files changed, 406 insertions(+)
+ create mode 100644 utils/gst-helper.c
+
+diff --git a/configure.ac b/configure.ac
+index 4825afa..9125871 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -141,6 +141,13 @@ AM_COND_IF([ENABLE_HCITOP], [
+ 	PKG_CHECK_MODULES([NCURSES], [ncurses])
+ ])
+ 
++AC_ARG_ENABLE([gsthelper],
++	[AS_HELP_STRING([--enable-gsthelper], [enable building of gsthelper tool])])
++AM_CONDITIONAL([ENABLE_GSTHELPER], [test "x$enable_gsthelper" = "xyes"])
++AM_COND_IF([ENABLE_GSTHELPER], [
++	PKG_CHECK_MODULES([GST], [gstreamer-1.0 glib-2.0])
++])
++
+ AC_ARG_ENABLE([test],
+ 	[AS_HELP_STRING([--enable-test], [enable unit test])])
+ AM_CONDITIONAL([ENABLE_TEST], [test "x$enable_test" = "xyes"])
+diff --git a/utils/Makefile.am b/utils/Makefile.am
+index 9057f2c..9790474 100644
+--- a/utils/Makefile.am
++++ b/utils/Makefile.am
+@@ -47,3 +47,23 @@ hcitop_LDADD = \
+ 	@LIBBSD_LIBS@ \
+ 	@NCURSES_LIBS@
+ endif
++
++if ENABLE_GSTHELPER
++bin_PROGRAMS += bluealsa-gst-helper
++bluealsa_gst_helper_SOURCES = \
++	../src/shared/dbus-client.c \
++	../src/shared/ffb.c \
++	../src/shared/log.c \
++	gst-helper.c
++bluealsa_gst_helper_CFLAGS = \
++	-I$(top_srcdir)/src \
++	@ALSA_CFLAGS@ \
++	@BLUEZ_CFLAGS@ \
++	@DBUS1_CFLAGS@ \
++	@GST_CFLAGS@
++bluealsa_gst_helper_LDADD = \
++	@ALSA_LIBS@ \
++	@BLUEZ_LIBS@ \
++	@DBUS1_LIBS@ \
++	@GST_LIBS@
++endif
+diff --git a/utils/gst-helper.c b/utils/gst-helper.c
+new file mode 100644
+index 0000000..1b021ee
+--- /dev/null
++++ b/utils/gst-helper.c
+@@ -0,0 +1,379 @@
++/* Bluez-Alsa PipeWire integration GStreamer helper
++ *
++ * Copyright © 2016-2019 Arkadiusz Bokowy
++ * Copyright © 2019 Collabora Ltd.
++ *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
++ *
++ * SPDX-License-Identifier: MIT
++ */
++
++#if HAVE_CONFIG_H
++# include <config.h>
++#endif
++
++#include <errno.h>
++#include <getopt.h>
++#include <poll.h>
++#include <pthread.h>
++#include <signal.h>
++#include <stdbool.h>
++#include <stdint.h>
++#include <stdio.h>
++#include <stdlib.h>
++#include <string.h>
++#include <unistd.h>
++
++#include <bluetooth/bluetooth.h>
++#include <dbus/dbus.h>
++#include <gst/gst.h>
++
++#include "shared/dbus-client.h"
++#include "shared/defs.h"
++#include "shared/ffb.h"
++#include "shared/log.h"
++
++struct worker {
++	/* used BlueALSA PCM device */
++	struct ba_pcm ba_pcm;
++	/* file descriptor of PCM FIFO */
++	int ba_pcm_fd;
++	/* file descriptor of PCM control */
++	int ba_pcm_ctrl_fd;
++	/* the gstreamer pipelines (sink & source) */
++	GstElement *pipeline[2];
++};
++
++static struct ba_dbus_ctx dbus_ctx;
++static GHashTable *workers;
++static bool main_loop_on = true;
++
++static void
++main_loop_stop(int sig)
++{
++	/* Call to this handler restores the default action, so on the
++	 * second call the program will be forcefully terminated. */
++
++	struct sigaction sigact = { .sa_handler = SIG_DFL };
++	sigaction(sig, &sigact, NULL);
++
++	main_loop_on = false;
++}
++
++static int
++worker_start_pipeline(struct worker *w, int id, int mode, int profile)
++{
++	GError *gerr = NULL;
++	DBusError err = DBUS_ERROR_INIT;
++
++	if (w->pipeline[id])
++		return 0;
++
++	if (!bluealsa_dbus_pcm_open(&dbus_ctx, w->ba_pcm.pcm_path, mode,
++				&w->ba_pcm_fd, &w->ba_pcm_ctrl_fd, &err)) {
++		error("Couldn't open PCM: %s", err.message);
++		dbus_error_free(&err);
++		goto fail;
++	}
++
++	if (mode == BA_PCM_FLAG_SINK) {
++		debug("sink start");
++		w->pipeline[id] = gst_parse_launch(
++			/* add a silent live source to ensure a perfect live stream on the
++			   output, even when the bt device is not sending or has gaps;
++			   this also effectively changes the clock to be the system clock,
++			   which is the same clock used by bluez-alsa on the sending side */
++			"audiotestsrc is-live=true wave=silence ! capsfilter name=capsf "
++			"! audiomixer name=m "
++			/* mix the input from bluez-alsa using fdsrc; rawaudioparse
++			   is necessary to convert bytes to time and align the buffers */
++			"fdsrc name=fdelem do-timestamp=true ! capsfilter name=capsf2 "
++			"! rawaudioparse use-sink-caps=true ! m. "
++			/* take the mixer output, convert and push to pipewire */
++			"m.src ! capsfilter name=capsf3 ! audioconvert ! audioresample "
++			"! audio/x-raw,format=F32LE,rate=48000 ! pwaudiosink name=pwelem",
++			&gerr);
++	} else if (mode == BA_PCM_FLAG_SOURCE && profile == BA_PCM_FLAG_PROFILE_SCO) {
++		debug("source start");
++		w->pipeline[id] = gst_parse_launch(
++			/* read from pipewire and put the buffers on a leaky queue, which
++			   will essentially allow pwaudiosrc to continue working while
++			   the fdsink is blocked (when there is no phone call in progress).
++			   9600 bytes = 50ms @ F32LE/1ch/48000
++			*/
++			"pwaudiosrc name=pwelem ! audio/x-raw,format=F32LE,rate=48000 "
++			"! queue leaky=downstream max-size-time=0 max-size-buffers=0 max-size-bytes=9600 "
++			"! audioconvert ! audioresample ! capsfilter name=capsf "
++			"! fdsink name=fdelem", &gerr);
++	}
++
++	if (gerr) {
++		error("Failed to start pipeline: %s", gerr->message);
++		g_error_free(gerr);
++		goto fail;
++	}
++
++	if (w->pipeline[id]) {
++		g_autofree gchar *capsstr = NULL;
++		g_autoptr (GstElement) fdelem = gst_bin_get_by_name(GST_BIN(w->pipeline[id]), "fdelem");
++		g_autoptr (GstElement) pwelem = gst_bin_get_by_name(GST_BIN(w->pipeline[id]), "pwelem");
++		g_autoptr (GstElement) capsf = gst_bin_get_by_name(GST_BIN(w->pipeline[id]), "capsf");
++		g_autoptr (GstElement) capsf2 = gst_bin_get_by_name(GST_BIN(w->pipeline[id]), "capsf2");
++		g_autoptr (GstElement) capsf3 = gst_bin_get_by_name(GST_BIN(w->pipeline[id]), "capsf3");
++		g_autoptr (GstCaps) caps = gst_caps_new_simple("audio/x-raw",
++				"format", G_TYPE_STRING, "S16LE",
++				"layout", G_TYPE_STRING, "interleaved",
++				"channels", G_TYPE_INT, w->ba_pcm.channels,
++				"rate", G_TYPE_INT, w->ba_pcm.sampling,
++				NULL);
++		g_autoptr (GstStructure) stream_props = gst_structure_new("props",
++				"media.role", G_TYPE_STRING, "Communication",
++				"wireplumber.keep-linked", G_TYPE_STRING, "1",
++				NULL);
++
++		g_object_set(capsf, "caps", caps, NULL);
++		if (capsf2)
++			g_object_set(capsf2, "caps", caps, NULL);
++		if (capsf3)
++			g_object_set(capsf3, "caps", caps, NULL);
++
++		capsstr = gst_caps_to_string (caps);
++		debug("  caps: %s", capsstr);
++
++		g_object_set(fdelem, "fd", w->ba_pcm_fd, NULL);
++		g_object_set(pwelem, "stream-properties", stream_props, NULL);
++
++		gst_element_set_state(w->pipeline[id], GST_STATE_PLAYING);
++	}
++
++	return 0;
++fail:
++	g_clear_object(&w->pipeline[id]);
++	return -1;
++}
++
++static int
++worker_start(struct worker *w)
++{
++	int mode = w->ba_pcm.flags & (BA_PCM_FLAG_SOURCE | BA_PCM_FLAG_SINK);
++	int profile = w->ba_pcm.flags & (BA_PCM_FLAG_PROFILE_A2DP | BA_PCM_FLAG_PROFILE_SCO);
++	/* human-readable BT address */
++	char addr[18];
++
++	g_return_val_if_fail (profile != 0 && profile != (BA_PCM_FLAG_PROFILE_A2DP | BA_PCM_FLAG_PROFILE_SCO), -1);
++
++	ba2str(&w->ba_pcm.addr, addr);
++	debug("%p: worker start addr:%s, mode:0x%x, profile:0x%x", w, addr, mode, profile);
++
++	if (mode & BA_PCM_FLAG_SINK)
++		worker_start_pipeline(w, 0, BA_PCM_FLAG_SINK, profile);
++	if (mode & BA_PCM_FLAG_SOURCE)
++		worker_start_pipeline(w, 1, BA_PCM_FLAG_SOURCE, profile);
++}
++
++static int
++worker_stop(struct worker *w)
++{
++	debug("stop worker %p", w);
++	if (w->pipeline[0]) {
++		gst_element_set_state(w->pipeline[0], GST_STATE_NULL);
++		g_clear_object(&w->pipeline[0]);
++	}
++	if (w->pipeline[1]) {
++		gst_element_set_state(w->pipeline[1], GST_STATE_NULL);
++		g_clear_object(&w->pipeline[1]);
++	}
++	if (w->ba_pcm_fd != -1) {
++		close(w->ba_pcm_fd);
++		w->ba_pcm_fd = -1;
++	}
++	if (w->ba_pcm_ctrl_fd != -1) {
++		close(w->ba_pcm_ctrl_fd);
++		w->ba_pcm_ctrl_fd = -1;
++	}
++	return 0;
++}
++
++static int
++supervise_pcm_worker(struct worker *worker)
++{
++	if (worker == NULL)
++		return -1;
++
++	/* no mode? */
++	if (worker->ba_pcm.flags & (BA_PCM_FLAG_SOURCE | BA_PCM_FLAG_SINK) == 0)
++		goto stop;
++
++	/* no profile? */
++	if (worker->ba_pcm.flags & (BA_PCM_FLAG_PROFILE_A2DP | BA_PCM_FLAG_PROFILE_SCO) == 0)
++		goto stop;
++
++	/* check whether SCO has selected codec */
++	if (worker->ba_pcm.flags & BA_PCM_FLAG_PROFILE_SCO &&
++			worker->ba_pcm.codec == 0) {
++		debug("Skipping SCO with codec not selected");
++		goto stop;
++	}
++
++start:
++	return worker_start(worker);
++stop:
++	return worker_stop(worker);
++}
++
++static void
++worker_new(struct ba_pcm *pcm)
++{
++	struct worker *w = g_slice_new0 (struct worker);
++	memcpy(&w->ba_pcm, pcm, sizeof(struct ba_pcm));
++	w->ba_pcm_fd = -1;
++	w->ba_pcm_ctrl_fd = -1;
++	g_hash_table_insert(workers, w->ba_pcm.pcm_path, w);
++	supervise_pcm_worker(w);
++}
++
++static DBusHandlerResult
++dbus_signal_handler(DBusConnection *conn, DBusMessage *message, void *data)
++{
++	(void)conn;
++	(void)data;
++
++	const char *path = dbus_message_get_path(message);
++	const char *interface = dbus_message_get_interface(message);
++	const char *signal = dbus_message_get_member(message);
++
++	DBusMessageIter iter;
++	struct worker *worker;
++
++	if (strcmp(interface, BLUEALSA_INTERFACE_MANAGER) == 0) {
++
++		if (strcmp(signal, "PCMAdded") == 0) {
++			struct ba_pcm pcm;
++			if (!dbus_message_iter_init(message, &iter) ||
++					!bluealsa_dbus_message_iter_get_pcm(&iter, NULL, &pcm)) {
++				error("Couldn't add new PCM: %s", "Invalid signal signature");
++				goto fail;
++			}
++			worker_new(&pcm);
++			return DBUS_HANDLER_RESULT_HANDLED;
++		}
++
++		if (strcmp(signal, "PCMRemoved") == 0) {
++			if (!dbus_message_iter_init(message, &iter) ||
++					dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_OBJECT_PATH) {
++				error("Couldn't remove PCM: %s", "Invalid signal signature");
++				goto fail;
++			}
++			dbus_message_iter_get_basic(&iter, &path);
++			g_hash_table_remove(workers, path);
++			return DBUS_HANDLER_RESULT_HANDLED;
++		}
++
++	}
++
++	if (strcmp(interface, DBUS_INTERFACE_PROPERTIES) == 0) {
++		worker = g_hash_table_lookup(workers, path);
++		if (!worker)
++			goto fail;
++		if (!dbus_message_iter_init(message, &iter) ||
++				dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_STRING) {
++			error("Couldn't update PCM: %s", "Invalid signal signature");
++			goto fail;
++		}
++		dbus_message_iter_get_basic(&iter, &interface);
++		dbus_message_iter_next(&iter);
++		if (!bluealsa_dbus_message_iter_get_pcm_props(&iter, NULL, &worker->ba_pcm))
++			goto fail;
++		supervise_pcm_worker(worker);
++		return DBUS_HANDLER_RESULT_HANDLED;
++	}
++
++fail:
++	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
++}
++
++static void
++destroy_worker(void *worker)
++{
++	struct worker *w = worker;
++	worker_stop(w);
++	g_slice_free(struct worker, w);
++}
++
++int
++main(int argc, char *argv[])
++{
++	int ret = EXIT_SUCCESS;
++
++	log_open(argv[0], false, false);
++	gst_init(&argc, &argv);
++	dbus_threads_init_default();
++
++	DBusError err = DBUS_ERROR_INIT;
++	if (!bluealsa_dbus_connection_ctx_init(&dbus_ctx, BLUEALSA_SERVICE, &err)) {
++		error("Couldn't initialize D-Bus context: %s", err.message);
++		return EXIT_FAILURE;
++	}
++
++	bluealsa_dbus_connection_signal_match_add(&dbus_ctx,
++			BLUEALSA_SERVICE, NULL, BLUEALSA_INTERFACE_MANAGER, "PCMAdded", NULL);
++	bluealsa_dbus_connection_signal_match_add(&dbus_ctx,
++			BLUEALSA_SERVICE, NULL, BLUEALSA_INTERFACE_MANAGER, "PCMRemoved", NULL);
++	bluealsa_dbus_connection_signal_match_add(&dbus_ctx,
++			BLUEALSA_SERVICE, NULL, DBUS_INTERFACE_PROPERTIES, "PropertiesChanged",
++			"arg0='"BLUEALSA_INTERFACE_PCM"'");
++
++	if (!dbus_connection_add_filter(dbus_ctx.conn, dbus_signal_handler, NULL, NULL)) {
++		error("Couldn't add D-Bus filter: %s", err.message);
++		return EXIT_FAILURE;
++	}
++
++	workers = g_hash_table_new_full(g_str_hash, g_str_equal, NULL, destroy_worker);
++
++	{
++		struct ba_pcm *pcms = NULL;
++		size_t pcms_count = 0, i;
++
++		if (!bluealsa_dbus_get_pcms(&dbus_ctx, &pcms, &pcms_count, &err))
++			warn("Couldn't get BlueALSA PCM list: %s", err.message);
++
++		for (i = 0; i < pcms_count; i++) {
++			worker_new(&pcms[i]);
++		}
++
++		free(pcms);
++	}
++
++	struct sigaction sigact = { .sa_handler = main_loop_stop };
++	sigaction(SIGTERM, &sigact, NULL);
++	sigaction(SIGINT, &sigact, NULL);
++
++	/* Ignore SIGPIPE, which may be received when writing to the bluealsa
++	   socket when it is closed on the remote end */
++	signal(SIGPIPE, SIG_IGN);
++
++	debug("Starting main loop");
++	while (main_loop_on) {
++
++		struct pollfd pfds[10];
++		nfds_t pfds_len = ARRAYSIZE(pfds);
++
++		if (!bluealsa_dbus_connection_poll_fds(&dbus_ctx, pfds, &pfds_len)) {
++			error("Couldn't get D-Bus connection file descriptors");
++			ret = EXIT_FAILURE;
++			goto out;
++		}
++
++		if (poll(pfds, pfds_len, -1) == -1 &&
++				errno == EINTR)
++			continue;
++
++		if (bluealsa_dbus_connection_poll_dispatch(&dbus_ctx, pfds, pfds_len))
++			while (dbus_connection_dispatch(dbus_ctx.conn) == DBUS_DISPATCH_DATA_REMAINS)
++				continue;
++
++	}
++
++out:
++	g_hash_table_unref(workers);
++	return ret;
++}
+-- 
+2.23.0
+
diff --git a/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa/bluealsa-gst-helper@.service b/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa/bluealsa-gst-helper@.service
new file mode 100644
index 00000000..495ab622
--- /dev/null
+++ b/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa/bluealsa-gst-helper@.service
@@ -0,0 +1,18 @@
+[Unit]
+Description=Bluetooth audio helper for user %i
+Requires=pipewire@%i.socket bluez-alsa.service
+After=pipewire@%i.socket bluez-alsa.service
+
+[Service]
+Type=simple
+Restart=on-failure
+ExecStart=/usr/bin/bluealsa-gst-helper
+
+Environment=XDG_RUNTIME_DIR=/run/user/%i
+Environment=DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/%i/bus
+
+User=%i
+Slice=user-%i.slice
+SupplementaryGroups=audio
+UMask=0077
+CapabilityBoundingSet=
diff --git a/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa_git.bbappend b/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa_git.bbappend
new file mode 100644
index 00000000..2f9699a8
--- /dev/null
+++ b/meta-pipewire/recipes-connectivity/bluez-alsa/bluez-alsa_git.bbappend
@@ -0,0 +1,35 @@
+FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+
+SRC_URI += "\
+    file://0001-utils-add-a-gstreamer-helper-application-for-interco.patch \
+    file://bluealsa-gst-helper@.service \
+    "
+
+PACKAGECONFIG += "gsthelper"
+PACKAGECONFIG[gsthelper] = "--enable-gsthelper, --disable-gsthelper, gstreamer1.0"
+
+do_install_append() {
+    if ${@bb.utils.contains('DISTRO_FEATURES', 'systemd', 'true', 'false', d)}; then
+        # install the service file
+        mkdir -p ${D}${systemd_system_unitdir}/
+        install -m 0644 ${WORKDIR}/bluealsa-gst-helper@.service ${D}${systemd_system_unitdir}/bluealsa-gst-helper@.service
+
+        # enable the helper to start together with afm-user-session
+        mkdir -p ${D}${systemd_system_unitdir}/afm-user-session@.target.wants
+        ln -sf ../bluealsa-gst-helper@.service ${D}${systemd_system_unitdir}/afm-user-session@.target.wants/bluealsa-gst-helper@.service
+    fi
+}
+
+PACKAGES =+ "${PN}-pipewire"
+
+FILES_${PN}-pipewire = "\
+    ${bindir}/bluealsa-gst-helper \
+    ${systemd_system_unitdir}/bluealsa-gst-helper@.service \
+    ${systemd_system_unitdir}/afm-user-session@.target.wants/bluealsa-gst-helper@.service \
+    "
+RDEPENDS_${PN}-pipewire += "\
+    bluez-alsa \
+    pipewire \
+    gstreamer1.0-plugins-base \
+    gstreamer1.0-pipewire \
+    "
diff --git a/meta-pipewire/recipes-core/packagegroups/packagegroup-pipewire.bb b/meta-pipewire/recipes-core/packagegroups/packagegroup-pipewire.bb
index 470310ad..4020f1e2 100644
--- a/meta-pipewire/recipes-core/packagegroups/packagegroup-pipewire.bb
+++ b/meta-pipewire/recipes-core/packagegroups/packagegroup-pipewire.bb
@@ -13,4 +13,5 @@ RDEPENDS_${PN} += "\
     pipewire \
     pipewire-alsa \
     gstreamer1.0-pipewire \
+    bluez-alsa-pipewire \
 "