Support PipeWire audio on more systems

First, support is added for using pipewire-media-session on systems that
haven't yet been migrated to WirePlumber. While pipewire-media-session
is effectively deprecated, it is still the only session manager on
enough systems to be worth supporting.

Second, the script now calls the pipewire binary directly to launch the
PulseAudio compatibility layer instead of via the pipewire-pulse
symlink. Support for the PulseAudio protocol is built into PipeWire, but
Debian has a separate package to install the pipewire-pulse symlink,
config file, user service, and documentation. Since CRD doesn't use the
user service and provides its own config file, bypassing the symlink
allows PipeWire audio forwarding to work even on systems without the
pipewire-pulse package installed.

(cherry picked from commit b253792)

Bug: 1457635
Change-Id: I542ef3b25b9f5bd9bdf6f5dcd0c674be1d11bbd3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4641281
Auto-Submit: Erik Jensen <rkjnsn@chromium.org>
Commit-Queue: Erik Jensen <rkjnsn@chromium.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1161964}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4643563
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Jamie Walch <jamiewalch@chromium.org>
Cr-Commit-Position: refs/branch-heads/5845@{#65}
Cr-Branched-From: 5a5dff6-refs/heads/main@{#1160321}

remoting/host/installer/linux/BUILD.gn

@@ -66,6 +66,7 @@ action("remoting_me2me_host_deb_installer") {
     "//remoting/host/linux/configure_url_forwarder.py",
     "//remoting/host/linux/linux_me2me_host.py",
     "//remoting/host/linux/pipewire.conf.template",
+    "//remoting/host/linux/pipewire-media-session.conf.template",
     "//remoting/host/linux/pipewire-pulse.conf.template",
     "//remoting/host/linux/wireplumber.conf.template",
     "$root_gen_dir/remoting/CREDITS.txt",

remoting/host/installer/linux/Makefile

@@ -64,6 +64,9 @@ install:
 	install -m 0644 \
 	  "$(SRC_DIR)/remoting/host/linux/pipewire.conf.template" \
 	  "$(INSTALL_DIR)/pipewire.conf.template"
+	install -m 0644 \
+	  "$(SRC_DIR)/remoting/host/linux/pipewire-media-session.conf.template" \
+	  "$(INSTALL_DIR)/pipewire-media-session.conf.template"
 	install -m 0644 \
 	  "$(SRC_DIR)/remoting/host/linux/pipewire-pulse.conf.template" \
 	  "$(INSTALL_DIR)/pipewire-pulse.conf.template"

remoting/host/installer/linux/debian/control

@@ -13,7 +13,7 @@ Homepage: https://chrome.google.com/remotedesktop
 Package: chrome-remote-desktop
 Architecture: any
 Depends: adduser, xvfb, xserver-xorg-video-dummy (>= 1:0.3.8-1), policykit-1, xbase-clients, psmisc, python3 (>= 3.5), python3-packaging, python3-psutil, python3-xdg (>= 0.25), ${shlibs:Depends}, ${misc:Depends}, ${python3:Depends}
-Recommends: xserver-xorg-video-dummy (>= 1:0.4.0), pipewire (>= 0.3.53), pipewire-pulse, wireplumber
+Recommends: xserver-xorg-video-dummy (>= 1:0.4.0), pipewire (>= 0.3.53)
 Suggests: google-chrome-stable | google-chrome-beta | google-chrome-unstable
 Description: Chrome Remote Desktop Beta
  Chrome Remote Desktop allows you to securely access your computer over the

remoting/host/linux/BUILD.gn

@@ -26,6 +26,7 @@ if (enable_me2me_host) {
 
   copy("remoting_me2me_host_copy_pipewire_templates") {
     sources = [
+      "pipewire-media-session.conf.template",
       "pipewire-pulse.conf.template",
       "pipewire.conf.template",
       "wireplumber.conf.template",

remoting/host/linux/linux_me2me_host.py

@@ -293,40 +293,53 @@ def is_googler_owned(config):
     return False
 
 
-def is_pipewire_supported():
-  for binary in ["pipewire", "pipewire-pulse", "wireplumber"]:
-    if shutil.which(binary) is None:
-      logging.warning(binary
-                      + " not found. Not enabling PipeWire audio support.")
-      return False
+def get_pipewire_session_manager():
+  """Returns the PipeWire session manager supported on this system (either
+  "wireplumber" or "pipewire-media-session"), or None if a supported PipeWire
+  installation is not found."""
+
+  if shutil.which("pipewire") is None:
+    logging.warning("PipeWire not found. Not enabling PipeWire audio support.")
+    return None
 
   try:
     version_output = subprocess.check_output(["pipewire", "--version"],
                                              universal_newlines=True)
   except subprocess.CalledProcessError as e:
     logging.warning("Failed to execute pipewire. Not enabling PipeWire audio"
                     + " support: " + str(e))
-    return False
+    return None
 
   match = re.search(r"pipewire (\S+)$", version_output, re.MULTILINE)
   if not match:
     logging.warning("Failed to determine pipewire version. Not enabling"
                     + " PipeWire audio support.")
-    return False
+    return None
 
   try:
     pipewire_version = version.parse(match[1])
   except version.InvalidVersion as e:
     logging.warning("Failed to parse pipewire version. Not enabling PipeWire"
                     + " audio support: " + str(e))
-    return False
+    return None
 
   if pipewire_version < version.parse("0.3.53"):
     logging.warning("Installed pipewire version is too old. Not enabling"
                     + " PipeWire audio support.")
-    return False
+    return None
+
+  session_manager = None
+  for binary in ["wireplumber", "pipewire-media-session"]:
+    if shutil.which(binary) is not None:
+      session_manager = binary
+      break
 
-  return True
+  if session_manager is None:
+    logging.warning("No session manager found. Not enabling PipeWire audio"
+                    + " support.")
+    return None
+
+  return session_manager
 
 
 def terminate_process(pid, name):
@@ -544,7 +557,8 @@ def __init__(self, sizes, server_inhibitor=None, pipewire_inhibitor=None,
     self.server_proc = None
     self.pipewire_proc = None
     self.pipewire_pulse_proc = None
-    self.wireplumber_proc = None
+    self.pipewire_session_manager = None
+    self.pipewire_session_manager_proc = None
     self.pre_session_proc = None
     self.session_proc = None
     self.host_proc = None
@@ -624,12 +638,13 @@ def _setup_gnubby(self):
     self.child_env["SSH_AUTH_SOCK"] = self.ssh_auth_sockname
 
   def _launch_pipewire(self, instance_name, runtime_path, sink_name):
-    if not is_pipewire_supported():
+    self.pipewire_session_manager = get_pipewire_session_manager()
+    if self.pipewire_session_manager is None:
       return False
 
     try:
       for config_file in ["pipewire.conf", "pipewire-pulse.conf",
-                          "wireplumber.conf"]:
+                          self.pipewire_session_manager + ".conf"]:
         with (open(os.path.join(SCRIPT_DIR, config_file + ".template"), "r")
                 as infile,
               open(os.path.join(runtime_path, config_file), "w") as outfile):
@@ -642,20 +657,28 @@ def _launch_pipewire(self, instance_name, runtime_path, sink_name):
       logging.info("Launching pipewire")
       pipewire_cmd = ["pipewire", "-c",
                       os.path.join(runtime_path, "pipewire.conf")]
-      pipewire_pulse_cmd = ["pipewire-pulse", "-c",
+      # PulseAudio protocol support is built into PipeWire for the versions we
+      # support. Invoking the pipewire binary directly instead of via the
+      # pipewire-pulse symlink allows this to work even if the pipewire-pulse
+      # package is not installed (e.g., if the user is still using PulseAudio
+      # for local sessions).
+      pipewire_pulse_cmd = ["pipewire", "-c",
                       os.path.join(runtime_path, "pipewire-pulse.conf")]
-      wireplumber_cmd = ["wireplumber", "-c",
-                      os.path.join(runtime_path, "wireplumber.conf")]
+      session_manager_cmd = [
+          self.pipewire_session_manager, "-c",
+          os.path.join(runtime_path, self.pipewire_session_manager + ".conf")]
 
       # Terminate any stale processes before relaunching.
-      for command in [pipewire_cmd, pipewire_pulse_cmd, wireplumber_cmd]:
+      for command in [pipewire_cmd, pipewire_pulse_cmd, session_manager_cmd]:
         terminate_command_if_running(command)
 
       self.pipewire_proc = subprocess.Popen(pipewire_cmd, env=self.child_env)
       self.pipewire_pulse_proc = subprocess.Popen(pipewire_pulse_cmd,
                                                   env=self.child_env)
-      self.wireplumber_proc = subprocess.Popen(wireplumber_cmd,
-                                               env=self.child_env)
+      # MEDIA_SESSION_CONFIG_DIR is needed to use an absolute path with
+      # pipewire-media-session.
+      self.pipewire_session_manager_proc = subprocess.Popen(session_manager_cmd,
+          env={**self.child_env, "MEDIA_SESSION_CONFIG_DIR": "/"})
 
       # Directs native PipeWire clients to the correct instance
       self.child_env["PIPEWIRE_REMOTE"] = instance_name
@@ -667,12 +690,13 @@ def _launch_pipewire(self, instance_name, runtime_path, sink_name):
       # Clean up any processes that did start
       for proc, name in [(self.pipewire_proc, "pipewire"),
                          (self.pipewire_pulse_proc, "pipewire-pulse"),
-                         (self.wireplumber_proc, "wireplumber")]:
+                         (self.pipewire_session_manager_proc,
+                          self.pipewire_session_manager)]:
         if proc is not None:
           terminate_process(proc.pid, name)
       self.pipewire_proc = None
       self.pipewire_pulse_proc = None
-      self.wireplumber_proc = None
+      self.pipewire_session_manager_proc = None
 
     return False
 
@@ -799,14 +823,15 @@ def cleanup(self):
                        (self.pre_session_proc, "pre-session"),
                        (self.pipewire_proc, "pipewire"),
                        (self.pipewire_pulse_proc, "pipewire-pulse"),
-                       (self.wireplumber_proc, "wireplumber"),
+                       (self.pipewire_session_manager_proc,
+                        self.pipewire_session_manager),
                        (self.server_proc, "display server")]:
       if proc is not None:
         terminate_process(proc.pid, name)
     self.server_proc = None
     self.pipewire_proc = None
     self.pipewire_pulse_proc = None
-    self.wireplumber_proc = None
+    self.pipewire_session_manager_proc = None
     self.pre_session_proc = None
     self.session_proc = None
     self.host_proc = None
@@ -864,22 +889,24 @@ def on_process_exit(self, pid, status):
       self.pipewire_pulse_proc = None
       pipewire_process = True
 
-    if self.wireplumber_proc is not None and pid == self.wireplumber_proc.pid:
-      logging.info("WirePlumber process terminated")
-      self.wireplumber_proc = None
+    if (self.pipewire_session_manager_proc is not None
+        and pid == self.pipewire_session_manager_proc.pid):
+      logging.info(self.pipewire_session_manager + " process terminated")
+      self.pipewire_session_manager_proc = None
       pipewire_process = True
 
     if pipewire_process:
       self.pipewire_inhibitor.record_stopped(expected=False)
       # Terminate other PipeWire-related processes to start fresh.
       for proc, name in [(self.pipewire_proc, "pipewire"),
                          (self.pipewire_pulse_proc, "pipewire-pulse"),
-                         (self.wireplumber_proc, "wireplumber")]:
+                         (self.pipewire_session_manager_proc,
+                          self.pipewire_session_manager)]:
         if proc is not None:
           terminate_process(proc.pid, name)
       self.pipewire_proc = None
       self.pipewire_pulse_proc = None
-      self.wireplumber_proc = None
+      self.pipewire_session_manager_proc = None
 
     if self.session_proc is not None and pid == self.session_proc.pid:
       logging.info("Session process terminated")
@@ -2543,7 +2570,7 @@ def main():
       logging.info("Waiting before relaunching")
     else:
       if (desktop.pipewire_proc is None and desktop.pipewire_pulse_proc is None
-          and desktop.wireplumber_proc is None
+          and desktop.pipewire_session_manager_proc is None
           and not desktop.pipewire_inhibitor.disabled
           and desktop.pipewire_inhibitor.failures < MAX_LAUNCH_FAILURES):
         desktop.setup_audio(host.host_id, backoff_time)

remoting/host/linux/pipewire-media-session.conf.template

@@ -0,0 +1,24 @@
+context.properties = {
+    remote.name = "$instance_name"
+}
+
+context.modules = [
+    { name = libpipewire-module-protocol-native }
+    { name = libpipewire-module-client-node }
+    { name = libpipewire-module-client-device }
+    { name = libpipewire-module-adapter }
+    { name = libpipewire-module-metadata }
+
+    { name = libpipewire-module-session-manager }
+]
+
+session.modules = {
+    default = [
+        flatpak                 # manages flatpak access
+        portal                  # manage portal permissions
+        suspend-node            # suspend inactive nodes
+        policy-node             # configure and link nodes
+        metadata                # export metadata API
+        streams-follow-default  # move streams when default changes
+    ]
+}