feat(image): PulseAudio in the box, and the GL dispatcher for 32-bit helpers

Most desktop applications and games speak PulseAudio, and the box served only PipeWire, so they played no sound. pipewire-pulse now runs beside PipeWire, on a socket the workload can reach, and the workload is told its address. A 32-bit launcher helper also has a 32-bit overlay preloaded into it that links libGL.so.1; libglvnd's dispatcher alone satisfies that, with Mesa assumed rather than installed.

apps/nesinit/src/services.rs

@@ -193,6 +193,9 @@ pub const SERVICE_GID: u32 = 1000;
 /// workload, which is the property [`crate::ticket::Untrusted`] depends on.
 pub const AUDIO_DIR: &str = "/run/pipewire";
 
+/// The PulseAudio socket PipeWire serves, beside its own in [`AUDIO_DIR`].
+pub const PULSE_SOCKET: &str = "/run/pipewire/pulse-native";
+
 /// Where a service's runtime sockets live.
 pub const RUNTIME_DIR: &str = "/run/user/1000";
 
@@ -354,6 +357,26 @@ pub const STACK: &[Service] = &[
         ready: Some("/run/pipewire/pipewire-0"),
         ready_name: None,
     },
+    Service {
+        name: "pipewire-pulse",
+        argv: &["/usr/bin/pipewire-pulse"],
+        env: &[
+            ("XDG_RUNTIME_DIR", RUNTIME_DIR),
+            ("PIPEWIRE_RUNTIME_DIR", AUDIO_DIR),
+            ("DBUS_SESSION_BUS_ADDRESS", "unix:path=/run/user/1000/bus"),
+        ],
+        user: Some((SERVICE_UID, SERVICE_GID)),
+        // Most desktop applications and games speak PulseAudio, not PipeWire.
+        cost: "applications that speak PulseAudio play no sound",
+        required: false,
+        // Beside PipeWire's socket and open to the workload the same way: its
+        // address is set in pipewire-pulse.conf.d and handed to the workload as
+        // PULSE_SERVER.
+        umask: Some(0),
+        realtime: true,
+        ready: Some(PULSE_SOCKET),
+        ready_name: None,
+    },
     Service {
         name: "wireplumber",
         argv: &["/usr/bin/wireplumber"],

apps/nesinit/src/workload.rs

@@ -1005,6 +1005,8 @@ const GRAPHICS: &[(&str, &str)] = &[
     // reach and both are told where. Without this a game renders and plays
     // silently, having looked under its own uid and found nothing.
     ("PIPEWIRE_RUNTIME_DIR", crate::services::AUDIO_DIR),
+    // And the same for PulseAudio, which most applications speak.
+    ("PULSE_SERVER", concat!("unix:", "/run/pipewire/pulse-native")),
 ];
 
 /// Mount one share where the descriptor says to put it.

build/Containerfile

@@ -393,7 +393,7 @@ RUN pacman -Syu --noconfirm --needed \
         libglvnd libdrm libepoxy libxxf86vm libinput wayland \
         expat zlib llvm-libs lm_sensors elfutils libva shaderc vulkan-icd-loader \
         pixman libxkbcommon xcb-util-keysyms xorg-xwayland \
-        pipewire pipewire-audio wireplumber opus \
+        pipewire pipewire-audio pipewire-pulse wireplumber opus \
         python libunwind sdl2-compat \
         python-xlib python-urllib3 python-pyzstd \
         libvpx speex libtheora libvdpau jsoncpp \
@@ -685,22 +685,30 @@ RUN umu-run --help >/dev/null 2>&1 \
     || { echo "umu-run does not start; run it by hand to see the module or interpreter it lacks" >&2; \
          umu-run --help >&2 || true; exit 1; }
 
-# The 32-bit C library, and nothing else 32-bit. A launcher's process helper
+# The 32-bit C library and GL dispatcher, and nothing else 32-bit. A launcher's process helper
 # is still a 32-bit program even in a 64-bit client -- Steam's `reaper`, which
 # every game is started through, needs only libc and libpthread -- and with no
 # 32-bit loader every launch exits 255 before the game runs, with no message.
-# No graphics stack comes with it: games bring their own runtime.
+# The launcher also preloads its 32-bit overlay into that helper, and the overlay
+# links libGL.so.1: libglvnd's dispatcher satisfies the link, and Mesa is
+# assumed rather than installed because the helper never draws. No graphics
+# driver comes with it: games bring their own runtime.
 RUN printf '\n[multilib]\nInclude = /etc/pacman.d/mirrorlist\n' >> /etc/pacman.conf \
     && pacman -Sy --noconfirm --needed lib32-glibc \
+    && pacman -S --noconfirm --needed \
+        --assume-installed lib32-mesa --assume-installed lib32-opengl-driver \
+        lib32-libglvnd \
     && pacman -Scc --noconfirm \
-    && test -x /usr/lib32/ld-linux.so.2
+    && test -x /usr/lib32/ld-linux.so.2 \
+    && test -e /usr/lib32/libGL.so.1
 
 # No other 32-bit libraries. The distribution's umu package would have brought a
 # long list of them for the container runtime this image never runs, which is
 # why it is built instead of installed; this is the check that stays true if
 # somebody swaps it back.
-RUN ! pacman -Qq | grep '^lib32-' | grep -qvx 'lib32-glibc' \
+RUN ! pacman -Qq | grep '^lib32-' \
-    || { echo "a lib32 package other than lib32-glibc is installed:" >&2; \
+        | grep -qvxE 'lib32-(glibc|libglvnd|libx11|libxext|libxcb|libxau|libxdmcp)' \
+    || { echo "a lib32 package beyond the helper's libc and GL dispatcher is installed:" >&2; \
          pacman -Qq | grep '^lib32-' >&2; exit 1; }
 
 # ───────────────────────────────────────────────────────────

build/etc/pipewire/pipewire-pulse.conf.d/50-nestri.conf

@@ -0,0 +1,5 @@
+# Serve PulseAudio beside PipeWire's own socket, where the workload -- another
+# user -- can reach it. The workload is told this address in PULSE_SERVER.
+pulse.properties = {
+    server.address = [ "unix:/run/pipewire/pulse-native" ]
+}