Felix Förtsch
1ece944a45
Share one Steam game library across multiple Linux users with fully isolated Proton prefixes. Uses bubblewrap to create a per-user kernel overlay on /opt/steam/steamapps/compatdata/ so game files stay shared while Proton prefixes are isolated per user, with no compatibility tool selection or per-game configuration required. Includes: - steam-shared launcher that sets up the per-user overlay and execs Steam inside a bwrap mount namespace - activate/uninstall scripts plus an add-user helper for steamshare group membership - permission watcher (steam-fix-perms.path/.service) to keep ACLs correct under pressure-vessel's restrictive mode bits - .desktop override that routes the system Steam launcher through steam-shared - Nix flake exposing activate, uninstall, and add-user packages - design doc and implementation plan covering the approach
117 lines
3.8 KiB
Bash
Executable File
117 lines
3.8 KiB
Bash
Executable File
#!/usr/bin/env bash
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# activate.sh — set up the shared Steam library system
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# Requires sudo. Idempotent — safe to re-run.
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set -euo pipefail
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STEAM_GROUP="steamshare"
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STEAM_DIR="/opt/steam"
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SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
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PROJECT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
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# --- preflight ---
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if [[ $EUID -ne 0 ]]; then
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echo "error: run this script with sudo" >&2
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exit 1
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fi
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if ! command -v bwrap &>/dev/null; then
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echo "error: bubblewrap (bwrap) is not installed" >&2
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echo " arch/cachyos: pacman -S bubblewrap" >&2
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echo " debian/ubuntu: apt install bubblewrap" >&2
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exit 1
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fi
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echo "[1/7] Group"
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if ! getent group "$STEAM_GROUP" >/dev/null; then
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groupadd "$STEAM_GROUP"
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echo " created group $STEAM_GROUP"
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else
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echo " group $STEAM_GROUP exists"
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fi
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echo "[2/7] Shared library directory"
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mkdir -p "$STEAM_DIR/steamapps/compatdata"
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find "$STEAM_DIR" -type d -exec chmod 2775 {} +
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chown -R root:"$STEAM_GROUP" "$STEAM_DIR"
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setfacl -R -m g:"$STEAM_GROUP":rwx "$STEAM_DIR"
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setfacl -dR -m g:"$STEAM_GROUP":rwx "$STEAM_DIR"
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echo " $STEAM_DIR ready (setgid + ACLs)"
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echo "[3/7] Clean stale compatdata prefixes"
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# Only wipe compatdata contents on first activation. Re-running activate.sh
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# on a live system would otherwise delete every user's Proton prefixes
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# (they live inside compatdata/<appid>/pfx, not in the per-user overlay
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# until the game is launched at least once under the shared-library setup).
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# A launcher at /usr/local/bin/steam-shared is proof the system has been
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# activated before — skip the wipe in that case.
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if [[ -e /usr/local/bin/steam-shared ]]; then
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echo " skipped (steam-shared already installed — refusing to wipe live prefixes)"
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else
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# remove all contents inside compatdata app dirs (not the dirs themselves —
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# Steam recreates empty ones and they're harmless as lower-layer placeholders)
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find "$STEAM_DIR/steamapps/compatdata" -mindepth 2 -delete 2>/dev/null || true
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echo " compatdata cleaned"
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fi
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echo "[4/7] Install launcher"
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install -m 755 "$PROJECT_DIR/scripts/steam-shared.sh" /usr/local/bin/steam-shared
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echo " /usr/local/bin/steam-shared installed"
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echo "[5/7] Install .desktop override"
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mkdir -p /usr/local/share/applications
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install -m 644 "$PROJECT_DIR/desktop/steam.desktop" /usr/local/share/applications/steam.desktop
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echo " .desktop override installed"
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echo "[6/7] Install permission watcher"
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install -m 755 "$PROJECT_DIR/scripts/fix-perms.sh" /usr/local/bin/steam-fix-perms
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cat > /etc/systemd/system/steam-fix-perms.service << 'UNIT'
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[Unit]
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Description=Fix shared Steam library permissions after pressure-vessel changes
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[Service]
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Type=oneshot
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ExecStart=/usr/local/bin/steam-fix-perms
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UNIT
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cat > /etc/systemd/system/steam-fix-perms.path << UNIT
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[Unit]
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Description=Watch shared Steam library for permission changes
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[Path]
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PathChanged=$STEAM_DIR/steamapps/common
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PathChanged=$STEAM_DIR/steamapps/shadercache
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TriggerLimitIntervalSec=10
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TriggerLimitBurst=1
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[Install]
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WantedBy=multi-user.target
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UNIT
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systemctl daemon-reload
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systemctl enable --now steam-fix-perms.path
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echo " permission watcher enabled"
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echo "[7/7] Fix current permissions"
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bash "$PROJECT_DIR/scripts/fix-perms.sh"
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echo " permissions fixed"
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echo
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echo "========================================"
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echo " Activation complete."
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echo
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echo " Shared library: $STEAM_DIR"
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echo " Launcher: /usr/local/bin/steam-shared"
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echo " Desktop file: /usr/local/share/applications/steam.desktop"
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echo
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echo " To add a user:"
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echo " sudo usermod -aG $STEAM_GROUP <username>"
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echo " (user must log out and back in)"
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echo
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echo " Each user must:"
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echo " 1. Launch Steam (it uses the shared library launcher automatically)"
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echo " 2. Steam → Settings → Storage → add $STEAM_DIR"
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echo " 3. Use any Proton version — isolation is automatic"
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echo "========================================"
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