GNOME prototype: detect GNOME/GDM, GDM autologin and session switching

lib/backend.sh

@@ -178,8 +178,7 @@ backend_apply() {
 
     backend_sudo || return 1
 
-    LOGIN_MANAGER=plasmalogin
-    [[ "${WANTED[single]}" == 1 ]] && LOGIN_MANAGER=sddm
+    choose_login_manager
     local -a failed=()
     for c in "${TO_DISABLE[@]}"; do
         if backend_run_component "$c" disable; then feature_record "$c" disable; else failed+=("$c"); fi

lib/boot-session.sh

@@ -23,7 +23,7 @@ boot_enable() {
     # the session into the base config; run it right away rather than rely
     # on its path unit, which could still be pending when the login manager
     # starts.
-    service_file "$BOOT_UNIT_NAME" SESSION_SYNC="$SESSION_SYNC" | sudo tee "$BOOT_UNIT" > /dev/null
+    service_file "$BOOT_UNIT_NAME" SESSION_SYNC="$SESSION_SYNC" DESKTOP_SESSION="$(desktop_session_file)" | sudo tee "$BOOT_UNIT" > /dev/null
     sudo systemctl daemon-reload
     sudo systemctl enable "$BOOT_UNIT_NAME" || { err "Enabling $BOOT_UNIT_NAME failed."; return 1; }
     ok "Boots into the desktop from the next boot on (Return to Gaming Mode still works)."

lib/desktop-shortcut.sh

@@ -23,7 +23,10 @@ create_desktop_shortcut() {
     # the shortcut can't sudo for interactively (Terminal=false), so it gets
     # a password-less rule scoped to exactly those two commands.
     local exec_line="steamos-session-select gamescope"
-    if [[ "$LOGIN_MANAGER" == "plasmalogin" ]]; then
+    if [[ "$LOGIN_MANAGER" == "gdm" ]]; then
+        # Its own steamos-session-select (lib/login-manager.sh) restarts GDM, through the helper and rule gdm_fix_install adds.
+        :
+    elif [[ "$LOGIN_MANAGER" == "plasmalogin" ]]; then
         exec_line="sh -c 'steamos-session-select gamescope && sudo -n /usr/bin/systemctl start sync-steamos-session.service && sudo -n /usr/bin/systemctl restart plasmalogin'"
         local sudoers_tmp
         sudoers_tmp="$(mktemp)"
@@ -40,6 +43,9 @@ EOF
     else
         sudo rm -f /etc/sudoers.d/gamescope-session-switch
     fi
+    # GNOME shows no icons on the desktop: the application grid gets the shortcut too.
+    gnome_app_shortcut=false
+    [[ "$(desktop_kind)" == gnome ]] && gnome_app_shortcut=true
 
     # SteamOS itself uses Valve's "gaming-return" icon (Steam logo with a
     # return arrow; the Deck-style arrow is only used on Steam Deck
@@ -66,6 +72,12 @@ EOF
 
     # Fix permissions for the target user and KDE Plasma desktop ecosystem
     chmod +x "$shortcut_path"
+    if [[ "$gnome_app_shortcut" == true ]]; then
+        mkdir -p "$user_home/.local/share/applications"
+        cp "$shortcut_path" "$user_home/.local/share/applications/steamify-return-to-gaming-mode.desktop"
+        # GNOME only starts launchers it trusts.
+        gio set "$shortcut_path" metadata::trusted true 2>/dev/null || true
+    fi
 
     ok "Desktop shortcut created successfully."
 }
@@ -81,6 +93,6 @@ set_shortcut_icon() {
 remove_desktop_shortcut() {
     local desktop_dir
     desktop_dir="$(xdg-user-dir DESKTOP 2>/dev/null || echo "$HOME/Desktop")"
-    rm -f "$desktop_dir/Return to Gaming Mode.desktop"
+    rm -f "$desktop_dir/Return to Gaming Mode.desktop" "$HOME/.local/share/applications/steamify-return-to-gaming-mode.desktop"
     sudo rm -f /etc/sudoers.d/gamescope-session-switch
 }

lib/desktop.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+# Which desktop Steamify is running on (KDE Plasma or GNOME), and the
+# session the login manager has to start for it. GNOME (GDM) is a prototype.
+# Sourced by steamify.sh; not meant to be run on its own.
+
+desktop_kind() {
+    # gnome or kde: the running session first, else what the login manager
+    # is (GDM means GNOME), else KDE, which Steamify was made for.
+    case ":${STEAMIFY_DESKTOP:-${XDG_CURRENT_DESKTOP:-}}:" in
+        *:GNOME:*|*:gnome:*) echo gnome; return ;;
+        *:KDE:*|*:kde:*) echo kde; return ;;
+    esac
+    [[ "$(current_display_manager)" == gdm ]] && { echo gnome; return; }
+    echo kde
+}
+
+desktop_session_file() {
+    # The login manager's session entry for the desktop: plasma.desktop, or
+    # whichever GNOME one is installed (gnome.desktop, gnome-xorg.desktop).
+    local f
+    if [[ "$(desktop_kind)" == gnome ]]; then
+        for f in /usr/share/wayland-sessions/gnome*.desktop /usr/share/xsessions/gnome*.desktop; do
+            [[ -f "$f" ]] && { basename "$f"; return; }
+        done
+        echo gnome.desktop
+    else
+        echo plasma.desktop
+    fi
+}
+
+choose_login_manager() {
+    # LOGIN_MANAGER for gaming_enable: gdm on GNOME, else sddm with single
+    # user mode and plasmalogin without.
+    if [[ "$(desktop_kind)" == gnome ]]; then LOGIN_MANAGER=gdm
+    elif [[ "${WANTED[single]:-0}" == 1 ]]; then LOGIN_MANAGER=sddm
+    else LOGIN_MANAGER=plasmalogin; fi
+}

lib/login-manager.sh

@@ -4,6 +4,11 @@
 # Sourced by steamify.sh; not meant to be run on its own.
 
 BASE_CONF="/etc/plasmalogin.conf"
+GDM_CONF="/etc/gdm/custom.conf"
+GDM_FIX_DIR=/usr/local/share/steamify-gdm
+GDM_HOOK=/etc/pacman.d/hooks/95-steamify-gdm.hook
+GDM_SUDOERS=/etc/sudoers.d/steamify-gdm-relogin
+GDM_RELOGIN=/usr/local/libexec/steamify-gdm-relogin
 
 # The "SteamOS conversion" menu item: gaming mode boot, the Return to
 # Gaming Mode shortcut and Steam on the desktop (lib/steam-desktop.sh).
@@ -14,6 +19,9 @@ gaming_status() {
         plasmalogin)
             sed -n '/^\[Autologin\]/,/^\[/p' "$BASE_CONF" 2>/dev/null | grep -qx "User=$USER" &&
                 [[ -f /etc/systemd/system/sync-steamos-session.path ]] ;;
+        gdm)
+            sed -n '/^\[daemon\]/,/^\[/p' /etc/gdm/custom.conf 2>/dev/null | grep -qx "AutomaticLogin=$USER" &&
+                [[ -f "$GDM_FIX_DIR/steam-set-session" ]] ;;
         *) return 1 ;;
     esac
 }
@@ -108,6 +116,14 @@ gaming_enable() {
             configure_autologin
             install_session_sync
             ;;
+        gdm)
+            # GNOME (prototype): GDM autologin, plus CachyOS's session tools made GDM-aware.
+            remove_sddm_autologin
+            remove_session_sync
+            switch_to_gdm || return 1
+            configure_gdm_autologin || return 1
+            gdm_fix_install || return 1
+            ;;
     esac
     # (NVIDIA with single user mode from before the conversion: its desktop autologin would pin the Plasma session.)
     single_login_release
@@ -122,8 +138,13 @@ gaming_disable() {
     info "Turning off booting into gaming mode..."
     remove_sddm_autologin
     remove_session_sync
-    restore_plasmalogin_config
-    switch_to_plasmalogin
+    if [[ "$(current_display_manager)" == gdm ]]; then
+        gdm_fix_remove
+        restore_gdm_config
+    else
+        restore_plasmalogin_config
+        switch_to_plasmalogin
+    fi
     remove_desktop_shortcut
     steam_disable
     gsn_disable
@@ -297,3 +318,75 @@ install_session_sync() {
     sudo cat "$BASE_CONF"
     echo
 }
+
+switch_to_gdm() {
+    # Already the login manager on a GNOME install; this only makes sure it is installed and enabled.
+    [[ "$(current_display_manager)" == gdm ]] && return 0
+    info "Installing and enabling GDM..."
+    sudo pacman -S --needed --noconfirm gdm || { err "Installing gdm failed."; return 1; }
+    local current
+    current="$(systemctl show -p Id --value display-manager 2>/dev/null)"
+    [[ -n "$current" && "$current" != gdm.service ]] && sudo systemctl disable "$current"
+    sudo systemctl enable -f gdm.service || { err "Enabling gdm failed."; return 1; }
+    ok "GDM is the login manager from the next boot on."
+}
+
+configure_gdm_autologin() {
+    # [daemon] AutomaticLogin: GDM reads it when it starts, which is why the
+    # session tools restart GDM to log in again (see patches/steamify-gdm-session-select.sh).
+    info "Configuring GDM autologin for $TARGET_USER"
+    sudo mkdir -p /etc/gdm
+    sudo touch "$GDM_CONF"
+    [[ -f "$GDM_CONF.bak-steamify" ]] || sudo cp -a "$GDM_CONF" "$GDM_CONF.bak-steamify"
+    sudo awk '
+        /^\[daemon\]/ { print; indaemon=1; next }
+        /^\[/ { indaemon=0 }
+        indaemon && /^(AutomaticLoginEnable|AutomaticLogin)=/ { next }
+        { print }
+    ' "$GDM_CONF" | sudo tee "$GDM_CONF.tmp" > /dev/null
+    grep -q '^\[daemon\]' "$GDM_CONF.tmp" || printf '[daemon]\n' | sudo tee -a "$GDM_CONF.tmp" > /dev/null
+    sudo sed -i "/^\[daemon\]/a AutomaticLoginEnable=True\nAutomaticLogin=$TARGET_USER" "$GDM_CONF.tmp"
+    sudo mv "$GDM_CONF.tmp" "$GDM_CONF"
+    ok "GDM autologin configured."
+}
+
+restore_gdm_config() {
+    if [[ -f "$GDM_CONF.bak-steamify" ]]; then
+        sudo cp -a "$GDM_CONF.bak-steamify" "$GDM_CONF" && sudo rm -f "$GDM_CONF.bak-steamify"
+    else
+        sudo sed -i '/^AutomaticLoginEnable=/d;/^AutomaticLogin=/d' "$GDM_CONF" 2>/dev/null
+    fi
+}
+
+gdm_fix_install() {
+    # CachyOS's steam-set-session and steamos-session-select only know
+    # plasma-login-manager/SDDM and KDE. Ours replace them at the same paths
+    # (Steam's Switch to Desktop calls them by path); a pacman hook puts them
+    # back after every update of gamescope-session-cachyos.
+    info "Making the session switching GDM-aware..."
+    sudo mkdir -p "$GDM_FIX_DIR"
+    patch_file steamify-gdm-steam-set-session.sh | sudo install -Dm755 /dev/stdin "$GDM_FIX_DIR/steam-set-session" &&
+        patch_file steamify-gdm-session-select.sh | fill DESKTOP_SESSION="$(desktop_session_file)" |
+            sudo install -Dm755 /dev/stdin "$GDM_FIX_DIR/steamos-session-select" || { err "Installing the GDM session tools failed."; return 1; }
+    patch_file steamify-gdm.hook | fill DIR="$GDM_FIX_DIR" | sudo install -Dm644 /dev/stdin "$GDM_HOOK"
+    # steamos-session-select logs in again through this helper (no password: it runs from the gaming session and from a shortcut).
+    patch_file steamify-gdm-relogin.sh | sudo install -Dm755 /dev/stdin "$GDM_RELOGIN"
+    echo "$TARGET_USER ALL=(root) NOPASSWD: $GDM_RELOGIN" | sudo install -Dm440 /dev/stdin "$GDM_SUDOERS"
+    sudo visudo -cf "$GDM_SUDOERS" > /dev/null || { sudo rm -f "$GDM_SUDOERS"; err "The sudoers rule for GDM is invalid."; return 1; }
+    for f in /usr/lib/steamos/steam-set-session /usr/bin/steamos-session-select; do
+        [[ -f "$f" && ! -f "$f.bak-steamify" ]] && sudo cp -a "$f" "$f.bak-steamify"
+    done
+    sudo install -m755 "$GDM_FIX_DIR/steam-set-session" /usr/lib/steamos/steam-set-session &&
+        sudo install -m755 "$GDM_FIX_DIR/steamos-session-select" /usr/bin/steamos-session-select || return 1
+    # Start in gamescope, as with the other login managers.
+    sudo /usr/lib/steamos/steam-set-session gamescope-session.desktop
+    ok "GDM autologin into gamescope is set up."
+}
+
+gdm_fix_remove() {
+    sudo rm -f "$GDM_HOOK" "$GDM_SUDOERS" "$GDM_RELOGIN"
+    for f in /usr/lib/steamos/steam-set-session /usr/bin/steamos-session-select; do
+        [[ -f "$f.bak-steamify" ]] && sudo mv "$f.bak-steamify" "$f"
+    done
+    sudo rm -rf "$GDM_FIX_DIR"
+}

lib/menu.sh

@@ -60,6 +60,8 @@ component_available() {
         # The SteamOS conversion is offered on NVIDIA PCs too: it installs the patched gamescope there (lib/gamescope-nvidia.sh)
         # and turns off "Gaming on NVIDIA" (lib/nvidia.sh), which is not offered any more (nvidia_available).
         nvidia|bigpicture|nvsilent) nvidia_available ;;
+        # Plasma only: the Vapor theme and single user mode (KDE Wallet, screen locker, Plasma's menu). Not on GNOME.
+        theme|single) [[ "$(desktop_kind)" == kde ]] ;;
         machine|poweroff) machine_available ;;
         vram) vram_available ;;
         # Steamify in the Steam library is for gaming mode's controller: not needed for Big Picture on the desktop (NVIDIA PCs;
@@ -503,8 +505,7 @@ plan_changes() {
 
 apply_changes() {
     local c failed=()
-    LOGIN_MANAGER=plasmalogin
-    [[ "${WANTED[single]}" == 1 ]] && LOGIN_MANAGER=sddm
+    choose_login_manager
 
     for c in "${TO_DISABLE[@]}"; do
         if [[ "$c" == boot ]]; then echo; echo -e "${c_bold}Boot into: gamescope${c_reset}"

lib/packages.sh

@@ -84,9 +84,11 @@ python_hid_shim_ensure() {
 
 install_required_packages() {
     # Step 2: gamescope/Steam and the desktop helpers the rest of the setup uses.
-    local -a MISSING
-    info "Checking required packages: gamescope-session-cachyos, steam, mangohud, xterm, ttf-liberation, wqy-zenhei, plasma-keyboard"
-    mapfile -t MISSING < <(pacman -T gamescope-session-cachyos steam mangohud xterm ttf-liberation wqy-zenhei plasma-keyboard)
+    local -a MISSING required=(gamescope-session-cachyos steam mangohud xterm ttf-liberation wqy-zenhei)
+    # Plasma's on-screen keyboard; on GNOME kconfig instead, for the kreadconfig6/kwriteconfig6 Steamify's undo journal uses.
+    if [[ "$(desktop_kind)" == gnome ]]; then required+=(kconfig accountsservice); else required+=(plasma-keyboard); fi
+    info "Checking required packages: ${required[*]}"
+    mapfile -t MISSING < <(pacman -T "${required[@]}")
 
     if [[ ${#MISSING[@]} -gt 0 ]]; then
         python_hid_shim_ensure || return 1

lib/steam-desktop.sh

@@ -9,8 +9,8 @@ steam_enable() {
     steam_env_dir="$HOME/.config/environment.d"
     mkdir -p "$steam_env_dir"
 
-    # 2. Prevent KDE Wayland from blocking the virtual keyboard overlay
-    echo "KWIN_IM_SHOW_ALWAYS=1" > "$steam_env_dir/99-kde-virtual-keyboard.conf"
+    # 2. Prevent KDE Wayland from blocking the virtual keyboard overlay (KWin only)
+    [[ "$(desktop_kind)" == kde ]] && echo "KWIN_IM_SHOW_ALWAYS=1" > "$steam_env_dir/99-kde-virtual-keyboard.conf"
 
     ok "Steam UI parameters and keyboard fix deployed successfully."
 }

patches/steamify-gdm-relogin.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+# Log the autologin user in again, into the session steam-set-session picked
+# (Steamify prototype, GDM). Run as root through sudo, from inside the session
+# that is being left. GDM logs in by itself only when the daemon starts, and
+# a new session refuses to start while the old user manager still runs
+# ("A graphical session is already running!"): so the user is ended first,
+# then GDM restarted. That work runs in its own transient unit, because
+# ending the user kills this process too.
+if [[ "$1" != --work ]]; then
+    [[ -n "${SUDO_USER:-}" ]] || exit 1
+    exec systemd-run --no-block --collect --unit=steamify-gdm-relogin "$0" --work "$SUDO_USER"
+fi
+USER_NAME="$2"
+# No waiting for the old user manager to go: systemd starts the new login
+# after it, and waiting only keeps GDM's login screen up in the meantime.
+loginctl terminate-user "$USER_NAME"
+systemctl restart gdm.service

patches/steamify-gdm-session-select.sh

@@ -0,0 +1,45 @@
+#!/bin/bash
+# steamos-session-select for GDM (Steamify prototype): CachyOS's own ends the
+# session with a KDE-only D-Bus call. GDM logs in by itself only when it
+# starts, so after the new session is set the user is ended and GDM restarted
+# (patches/steamify-gdm-relogin.sh): it then logs the autologin user straight into it.
+set -e
+
+DM_ID="$(systemctl show -p Id --value display-manager)"
+DM_ID="${DM_ID%.service}"
+DESKTOP_SESSION=@DESKTOP_SESSION@
+
+relogin() {
+    # Out of the running session into the one that was set.
+    case "$DM_ID" in
+        gdm) sudo -n /usr/local/libexec/steamify-gdm-relogin ;;
+        *) qdbus6 org.kde.Shutdown /Shutdown org.kde.Shutdown.logout ;;
+    esac
+}
+
+case "$1" in
+    persistent)
+        systemctl --user mask cachyos-gamescope-autologin.service
+        pkexec /usr/lib/steamos/steam-set-session "$DESKTOP_SESSION" ;;
+    oneshot)
+        systemctl --user unmask cachyos-gamescope-autologin.service
+        pkexec /usr/lib/steamos/steam-set-session gamescope-session.desktop ;;
+    gamescope)
+        pkexec /usr/lib/steamos/steam-set-session gamescope-session.desktop
+        relogin ;;
+    desktop|plasma|gnome)
+        pkexec /usr/lib/steamos/steam-set-session "$DESKTOP_SESSION"
+        steam -shutdown || true
+        systemctl --user stop gamescope-session.target || true
+        # Under GDM nothing logs in again by itself after the session ends.
+        [[ "$DM_ID" == gdm ]] && relogin ;;
+    *)
+        [[ -n "$1" ]] && echo -e "Unknown session '$1'\n"
+        echo "Usage: $(basename "$0") persistent|oneshot|gamescope|desktop"
+        exit 1 ;;
+esac
+
+if [[ -e /dev/input/.hidden ]]; then
+    pkexec mv /dev/input/.hidden/* /dev/input
+    pkexec rm -r /dev/input/.hidden
+fi

patches/steamify-gdm-steam-set-session.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+# steam-set-session with GDM support (Steamify prototype). CachyOS's own only
+# knows plasma-login-manager and SDDM and quietly does nothing on GDM. GDM
+# has no autologin fragment: it takes the user's session from
+# AccountsService, so that is where the session goes.
+set -e
+
+DM_ID="$(systemctl show -p Id --value display-manager)"
+DM_ID="${DM_ID%.service}"
+SESSION="${1:-gamescope-session.desktop}"
+
+case "$DM_ID" in
+    plasmalogin) CONF_FILE="/etc/plasmalogin.conf.d/zz-steamos-autologin.conf" ;;
+    sddm) CONF_FILE="/etc/sddm.conf.d/zz-steamos-autologin.conf" ;;
+    gdm)
+        if [[ -n "${PKEXEC_UID:-}" ]]; then TARGET_USER="$(id -un "$PKEXEC_UID")"
+        else TARGET_USER="${SUDO_USER:-$(logname 2>/dev/null)}"; fi
+        # At boot (steamify-boot-desktop.service) nobody is logged in: the autologin user.
+        [[ -n "$TARGET_USER" ]] || TARGET_USER="$(sed -n 's/^AutomaticLogin=//p' /etc/gdm/custom.conf 2>/dev/null)"
+        [[ -n "$TARGET_USER" ]] || exit 0
+        ACCOUNT="/var/lib/AccountsService/users/$TARGET_USER"
+        SESSION_ID="${SESSION%.desktop}"
+        mkdir -p /var/lib/AccountsService/users
+        touch "$ACCOUNT"
+        grep -q '^\[User\]' "$ACCOUNT" || echo "[User]" >> "$ACCOUNT"
+        for key in Session XSession; do
+            if grep -q "^$key=" "$ACCOUNT"; then sed -i "s|^$key=.*|$key=$SESSION_ID|" "$ACCOUNT"
+            else sed -i "/^\[User\]/a $key=$SESSION_ID" "$ACCOUNT"; fi
+        done
+        systemctl restart accounts-daemon 2>/dev/null || true
+        exit 0 ;;
+esac
+
+# Any other login manager: nothing to do.
+[[ -n "${CONF_FILE:-}" ]] || exit 0
+mkdir -p "$(dirname "$CONF_FILE")"
+printf '[Autologin]\nSession=%s\n' "$SESSION" > "$CONF_FILE"

patches/steamify-gdm.hook

@@ -0,0 +1,10 @@
+[Trigger]
+Operation = Install
+Operation = Upgrade
+Type = Package
+Target = gamescope-session-cachyos
+
+[Action]
+Description = Steamify: GDM support for gamescope-session-cachyos...
+When = PostTransaction
+Exec = /bin/sh -c 'install -m755 @DIR@/steam-set-session /usr/lib/steamos/steam-set-session && install -m755 @DIR@/steamos-session-select /usr/bin/steamos-session-select'

services/steamify-boot-desktop.service

@@ -1,10 +1,10 @@
 [Unit]
 Description=Steamify CachyOS: boot into the desktop instead of gaming mode
-Before=display-manager.service sddm.service plasmalogin.service
+Before=display-manager.service sddm.service plasmalogin.service gdm.service
 
 [Service]
 Type=oneshot
-ExecStart=/usr/lib/steamos/steam-set-session plasma.desktop
+ExecStart=/usr/lib/steamos/steam-set-session @DESKTOP_SESSION@
 ExecStart=/bin/sh -c '[ -x @SESSION_SYNC@ ] && exec @SESSION_SYNC@ || true'
 
 [Install]

steamify.sh

@@ -19,7 +19,7 @@ VERSION=2.12.0
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
-for lib in common state packages login-manager single-user steam-desktop steam-machine fremont-poweroff vram-booster hdmi-refresh nvidia gamescope-nvidia controllers cec boot-session vapor-theme steamos-extras bios desktop-shortcut wizard-shortcut steam-game update-notifier first-login menu backend; do
+for lib in common state desktop packages login-manager single-user steam-desktop steam-machine fremont-poweroff vram-booster hdmi-refresh nvidia gamescope-nvidia controllers cec boot-session vapor-theme steamos-extras bios desktop-shortcut wizard-shortcut steam-game update-notifier first-login menu backend; do
     # shellcheck source=/dev/null
     source "$SCRIPT_DIR/lib/$lib.sh"
 done