session: add disable-able systemd session target (#15776)

* add systemd session target

* session: stop graphical-session so we block, near other systemd cleanup

* session: don't start session ourselves if MANAGERPID is set

This avoids doing systemd stuff if we're already in a systemd-managed
session, like UWSM. Env vars and targets and such should already be
handled for us.

* session: store state, rather than rechecking env var at exit

---------

Co-authored-by: Dregu <dregu@dreg.us>

CMakeLists.txt

@@ -417,6 +417,9 @@ else()
   message(STATUS "SYSTEMD support is requested (NO_SYSTEMD not defined)...")
   add_compile_definitions(USES_SYSTEMD)
 
+  install(FILES ${CMAKE_SOURCE_DIR}/systemd/hyprland-session.target
+          DESTINATION ${CMAKE_INSTALL_LIBDIR}/systemd/user)
+
   # session file -uwsm
   if(NO_UWSM)
     message(STATUS "UWSM support is disabled...")

src/Compositor.cpp

@@ -542,7 +542,12 @@ void CCompositor::cleanEnvironment() {
     if (m_desktopEnvSet)
         unsetenv("XDG_CURRENT_DESKTOP");
 
-    if (m_aqBackend->hasSession() && !Env::envEnabled("HYPRLAND_NO_SD_VARS")) {
+    if (m_aqBackend->hasSession() && !Env::envEnabled("HYPRLAND_NO_SD_VARS") && !getenv("MANAGERPID")) {
+#ifdef USES_SYSTEMD
+        if (m_sdSessionTarget)
+            // stopping hyprland-session doesn't wait for dependent services; this does
+            Config::Supplementary::executor()->spawn("systemctl --user stop graphical-session.target");
+#endif
         const auto CMD =
 #ifdef USES_SYSTEMD
             "systemctl --user unset-environment DISPLAY WAYLAND_DISPLAY HYPRLAND_INSTANCE_SIGNATURE XDG_CURRENT_DESKTOP QT_QPA_PLATFORMTHEME PATH XDG_DATA_DIRS && hash "
@@ -789,7 +794,9 @@ void CCompositor::startCompositor() {
         /* Session-less Hyprland usually means a nest, don't update the env in that case */
         m_aqBackend->hasSession() &&
         /* Activation environment management is not disabled */
-        !Env::envEnabled("HYPRLAND_NO_SD_VARS")) {
+        !Env::envEnabled("HYPRLAND_NO_SD_VARS") &&
+        /* Being executed under systemd */
+        !getenv("MANAGERPID")) {
         const auto CMD =
 #ifdef USES_SYSTEMD
             "systemctl --user import-environment DISPLAY WAYLAND_DISPLAY HYPRLAND_INSTANCE_SIGNATURE XDG_CURRENT_DESKTOP QT_QPA_PLATFORMTHEME PATH XDG_DATA_DIRS && hash "
@@ -797,6 +804,12 @@ void CCompositor::startCompositor() {
 #endif
             "dbus-update-activation-environment --systemd WAYLAND_DISPLAY XDG_CURRENT_DESKTOP HYPRLAND_INSTANCE_SIGNATURE QT_QPA_PLATFORMTHEME PATH XDG_DATA_DIRS";
         Config::Supplementary::executor()->spawn(CMD);
+#ifdef USES_SYSTEMD
+        if (!Env::envEnabled("HYPRLAND_NO_SD_TARGET")) {
+            m_sdSessionTarget = true;
+            Config::Supplementary::executor()->spawn("systemctl --user start hyprland-session.target");
+        }
+#endif
     }
 
     Log::logger->log(Log::DEBUG, "Running on WAYLAND_DISPLAY: {}", m_wlDisplaySocket);

src/Compositor.hpp

@@ -74,6 +74,7 @@ class CCompositor {
     bool                     m_desktopEnvSet          = false;
     bool                     m_wantsXwayland          = true;
     bool                     m_onlyConfigVerification = false;
+    bool                     m_sdSessionTarget        = false;
 
     // ------------------------------------------------- //
 

systemd/hyprland-session.target

@@ -0,0 +1,6 @@
+[Unit]
+Description=Hyprland session
+BindsTo=graphical-session.target
+Wants=graphical-session-pre.target
+After=graphical-session-pre.target
+PropagatesStopTo=graphical-session.target