feat(packaging/arch): Arch + SteamOS install target (PKGBUILD + sysext)

Add packaging/arch: a PKGBUILD mirroring the rpm/deb artifact set (binary, udev rule, 32MB sysctl, systemd USER units with ExecStart rewritten, headless helpers, env templates, openapi), a pacman .install scriptlet, a systemd-sysext builder for immutable SteamOS, and a README. Builds the working tree via PF_SRCDIR (CI/dev) or a git tag (AUR). Arch's stock ffmpeg already ships NVENC, so deps collapse to ~10 packages with nvidia-utils/compositors as optdepends (never hard-depend on the driver, same invariant as rpm/deb). SteamOS delivery is a **systemd-sysext** (overlays /usr read-only from writable /var/lib/extensions/, survives A/B OS updates, no steamos-readonly disable) — pacman/distrobox/flatpak are all unsuitable for a host that needs uinput/uhid, the host PipeWire socket, the GPU node, and to spawn a compositor. KNOWN GAP, documented prominently: encode is NVENC-only (src/encode/linux.rs has no VAAPI backend), so this works on Arch+NVIDIA (and bazzite-deck-nvidia) but an AMD Steam Deck installs yet cannot encode until a hevc_vaapi backend is written — a code change, not packaging. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-14 11:43:48 +00:00
parent abc057fbfe
commit c548155dd9
4 changed files with 232 additions and 0 deletions
@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+# Wrap a built punktfunk-host pacman package into a systemd-sysext image — the update-survivable
+# way to add the host to an immutable Arch-derived distro (SteamOS 3): the .raw overlays /usr
+# read-only from the writable /var/lib/extensions/, so it persists across A/B OS updates with no
+# `steamos-readonly disable`. Needs `bsdtar`/`tar`, `squashfs-tools` (mksquashfs).
+#
+# Usage:  bash build-sysext.sh <punktfunk-host-*.pkg.tar.zst>
+# Output: punktfunk-host.raw
+set -euo pipefail
+
+PKG="${1:?usage: build-sysext.sh <punktfunk-host-*.pkg.tar.zst>}"
+[ -f "$PKG" ] || { echo "no such package: $PKG" >&2; exit 1; }
+NAME=punktfunk-host
+
+STAGE="$(mktemp -d)"
+trap 'rm -rf "$STAGE"' EXIT
+
+# A pacman package is a (zstd) tarball; a sysext only carries /usr (the host /etc, /var are the
+# system's). Extract just usr/ from the payload.
+if command -v bsdtar >/dev/null 2>&1; then
+  bsdtar -C "$STAGE" -xf "$PKG" usr
+else
+  tar -C "$STAGE" -xf "$PKG" usr
+fi
+
+# The marker systemd-sysext requires to merge the image. ID=_any merges onto ANY host os-release
+# (SteamOS, Arch, Bazzite); ARCHITECTURE pins it to x86-64 so it's never merged on the wrong arch.
+install -d "$STAGE/usr/lib/extension-release.d"
+cat > "$STAGE/usr/lib/extension-release.d/extension-release.$NAME" <<EOF
+ID=_any
+ARCHITECTURE=x86-64
+EOF
+
+OUT="$NAME.raw"
+rm -f "$OUT"
+mksquashfs "$STAGE" "$OUT" -all-root -noappend -quiet
+echo "built $OUT"
+echo "  install:  sudo cp $OUT /var/lib/extensions/ && sudo systemctl enable --now systemd-sysext"
+echo "  then:     systemctl --user enable --now $NAME"