pulse: add a small pulseaudio daemon

Add a small application that loads the pulse server and makes it
listen on the pulseaudio socket.
Add some systemd activation files to start the service.

src/daemon/meson.build

@@ -41,6 +41,14 @@ executable('pipewire',
   dependencies : [pipewire_dep, ],
 )
 
+executable('pipewire-pulse',
+  'pipewire-pulse.c',
+  install: true,
+  c_args : pipewire_c_args,
+  include_directories : [configinc, spa_inc],
+  dependencies : [pipewire_dep, ],
+)
+
 if get_option('systemd') and systemd.found()
   subdir('systemd')
 endif

src/daemon/pipewire-pulse.c

+/* PipeWire
+ *
+ * Copyright © 2020 Wim Taymans
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <signal.h>
+#include <getopt.h>
+
+#include <spa/utils/result.h>
+
+#include <pipewire/impl.h>
+
+#include "config.h"
+
+static const char *address;
+
+static void do_quit(void *data, int signal_number)
+{
+	struct pw_main_loop *loop = data;
+	pw_main_loop_quit(loop);
+}
+
+static void show_help(const char *name)
+{
+	fprintf(stdout, "%s [options]\n"
+		"  -h, --help                            Show this help\n"
+		"      --version                         Show version\n"
+		"  -a  --address                         comma separated list of addresses (Default %s)\n",
+		name,
+		address);
+}
+
+int main(int argc, char *argv[])
+{
+	struct pw_context *context;
+	struct pw_main_loop *loop;
+	struct pw_properties *properties;
+	char *args;
+	static const struct option long_options[] = {
+		{ "help",	no_argument,		NULL, 'h' },
+		{ "version",	no_argument,		NULL, 'V' },
+		{ "address",	required_argument,	NULL, 'a' },
+		{ NULL, 0, NULL, 0}
+	};
+	int c;
+
+	pw_init(&argc, &argv);
+
+	address = "unix:native";
+
+	while ((c = getopt_long(argc, argv, "hVa:", long_options, NULL)) != -1) {
+		switch (c) {
+		case 'h':
+			show_help(argv[0]);
+			return 0;
+		case 'V':
+			fprintf(stdout, "%s\n"
+				"Compiled with libpipewire %s\n"
+				"Linked with libpipewire %s\n",
+				argv[0],
+				pw_get_headers_version(),
+				pw_get_library_version());
+			return 0;
+		case 'a':
+			address = optarg;
+			fprintf(stdout, "set address %s\n", address);
+			break;
+		default:
+			return -1;
+		}
+	}
+
+	properties = pw_properties_new(
+				PW_KEY_CONTEXT_PROFILE_MODULES, "default,rtkit",
+				NULL);
+
+	loop = pw_main_loop_new(&properties->dict);
+	if (loop == NULL) {
+		pw_log_error("failed to create main-loop: %m");
+		return -1;
+	}
+
+	pw_loop_add_signal(pw_main_loop_get_loop(loop), SIGINT, do_quit, loop);
+	pw_loop_add_signal(pw_main_loop_get_loop(loop), SIGTERM, do_quit, loop);
+
+	context = pw_context_new(pw_main_loop_get_loop(loop), properties, 0);
+	if (context == NULL) {
+		pw_log_error("failed to create context: %m");
+		return -1;
+	}
+
+	args = spa_aprintf("server.address=%s", address);
+	if (pw_context_load_module(context,
+				"libpipewire-module-protocol-pulse",
+				args, NULL) == NULL) {
+		pw_log_error("failed to create pulse module: %m");
+		return -1;
+	}
+
+	pw_log_info("start main loop");
+	pw_main_loop_run(loop);
+	pw_log_info("leave main loop");
+
+	free(args);
+	pw_context_destroy(context);
+	pw_main_loop_destroy(loop);
+	pw_deinit();
+
+	return 0;
+}

src/daemon/systemd/user/meson.build

 systemd_user_services_dir = systemd.get_pkgconfig_variable('systemduserunitdir', define_variable : [ 'prefix', prefix])
 
-install_data(sources : 'pipewire.socket', install_dir : systemd_user_services_dir)
+install_data(
+  sources : ['pipewire.socket', 'pipewire-pulse.socket'],
+  install_dir : systemd_user_services_dir)
 
 systemd_config = configuration_data()
 systemd_config.set('PW_BINARY', join_paths(pipewire_bindir, 'pipewire'))
+systemd_config.set('PW_PULSE_BINARY', join_paths(pipewire_bindir, 'pipewire-pulse'))
 
 configure_file(input : 'pipewire.service.in',
                output : 'pipewire.service',
                configuration : systemd_config,
                install_dir : systemd_user_services_dir)
+
+configure_file(input : 'pipewire-pulse.service.in',
+               output : 'pipewire-pulse.service',
+               configuration : systemd_config,
+               install_dir : systemd_user_services_dir)

src/daemon/systemd/user/pipewire-pulse.service.in

+[Unit]
+Description=PipeWire PulseAudio
+
+# We require pipewire-pulse.socket to be active before starting the daemon, because
+# while it is possible to use the service without the socket, it is not clear
+# why it would be desirable.
+#
+# A user installing pipewire and doing `systemctl --user start pipewire-pulse`
+# will not get the socket started, which might be confusing and problematic if
+# the server is to be restarted later on, as the client autospawn feature
+# might kick in. Also, a start of the socket unit will fail, adding to the
+# confusion.
+#
+# After=pipewire-pulse.socket is not needed, as it is already implicit in the
+# socket-service relationship, see systemd.socket(5).
+Requires=pipewire-pulse.socket
+
+[Service]
+Type=simple
+ExecStart=@PW_PULSE_BINARY@
+Restart=on-failure
+
+[Install]
+Also=pipewire-pulse.socket
+WantedBy=default.target

src/daemon/systemd/user/pipewire-pulse.socket

+[Unit]
+Description=PipeWire PulseAudio
+
+[Socket]
+Priority=6
+Backlog=5
+ListenStream=%t/pulse/native
+
+[Install]
+WantedBy=sockets.target