Roll forward of 49346b0b

This add fix to avoid session specific environement variable to be
leaked into new session.

Also, it will restore the old systemd session variable upon shutting
down.

startkde/startplasma-wayland.cpp

@@ -26,6 +26,7 @@
 int main(int argc, char **argv)
 {
     QCoreApplication app(argc, argv);
+
     createConfigDirectory();
     setupCursor(true);
 
@@ -71,11 +72,17 @@ int main(int argc, char **argv)
 
     qputenv("XDG_SESSION_TYPE", "wayland");
 
+    auto oldSystemdEnvironment = getSystemdEnvironment();
     if (!syncDBusEnvironment()) {
         out << "Could not sync environment to dbus.\n";
         return 1;
     }
 
+    // We import systemd environment after we sync the dbus environment here.
+    // Otherwise it may leads to some unwanted order of applying environment
+    // variables (e.g. LANG and LC_*)
+    importSystemdEnvrionment();
+
     QStringList args;
     if (argc > 1) {
         args.reserve(argc);
@@ -88,7 +95,7 @@ int main(int argc, char **argv)
     runSync(QStringLiteral("kwin_wayland_wrapper"), args);
 
     out << "startplasmacompositor: Shutting down...\n";
-    cleanupPlasmaEnvironment();
+    cleanupPlasmaEnvironment(oldSystemdEnvironment);
     out << "startplasmacompositor: Done.\n";
 
     return 0;

startkde/startplasma-x11.cpp

@@ -95,12 +95,18 @@ int main(int argc, char **argv)
     setupPlasmaEnvironment();
     setupX11();
 
+    auto oldSystemdEnvironment = getSystemdEnvironment();
     if (!syncDBusEnvironment()) {
         // Startup error
         messageBox(QStringLiteral("Could not sync environment to dbus.\n"));
         return 1;
     }
 
+    // We import systemd environment after we sync the dbus environment here.
+    // Otherwise it may leads to some unwanted order of applying environment
+    // variables (e.g. LANG and LC_*)
+    importSystemdEnvrionment();
+
     if (!startPlasmaSession(false))
         return 1;
 
@@ -112,7 +118,7 @@ int main(int argc, char **argv)
 
     runSync(QStringLiteral("kdeinit5_shutdown"), {});
 
-    cleanupPlasmaEnvironment();
+    cleanupPlasmaEnvironment(oldSystemdEnvironment);
     cleanupX11();
 
     out << "startkde: Done.\n";

startkde/startplasma.cpp

@@ -88,6 +88,24 @@ int runSync(const QString &program, const QStringList &args, const QStringList &
     return p.exitCode();
 }
 
+bool isShellVariable(const QByteArray &name) {
+    return name == "_" || name.startsWith("SHLVL");
+}
+
+bool isSessionVariable(const QByteArray &name) {
+    // Check is variable is specific to session.
+    return name == "DISPLAY" || name == "XAUTHORITY" ||
+           name == "WAYLAND_DISPLAY" || name == "WAYLAND_SOCKET" ||
+           name.startsWith("XDG_");
+}
+
+void setEnvironmentVariable(const QByteArray &name, const QByteArray &value) {
+    if (qgetenv(name) != value) {
+        //        qCDebug(PLASMA_STARTUP) << "setting..." << env.left(idx) << env.mid(idx+1) << "was" << qgetenv(env.left(idx));
+        qputenv(name, value);
+    }
+}
+
 void sourceFiles(const QStringList &files)
 {
     QStringList filteredFiles;
@@ -108,17 +126,16 @@ void sourceFiles(const QStringList &files)
     auto envs = fullEnv.split('\0');
 
     for (auto &env : envs) {
-        if (env.startsWith("_=") || env.startsWith("SHLVL"))
-            continue;
-
         const int idx = env.indexOf('=');
-        if (Q_UNLIKELY(idx <= 0))
+        if (Q_UNLIKELY(idx <= 0)) {
             continue;
+        }
 
-        if (qgetenv(env.left(idx)) != env.mid(idx + 1)) {
-            //             qCDebug(PLASMA_STARTUP) << "setting..." << env.left(idx) << env.mid(idx+1) << "was" << qgetenv(env.left(idx));
-            qputenv(env.left(idx), env.mid(idx + 1));
+        const auto name = env.left(idx);
+        if (isShellVariable(name)) {
+            continue;
         }
+        setEnvironmentVariable(name, env.mid(idx + 1));
     }
 }
 
@@ -182,6 +199,56 @@ void setupCursor(bool wayland)
     qputenv("XCURSOR_SIZE", QByteArray::number(kcminputrc_mouse_cursorsize));
 }
 
+std::optional<QStringList> getSystemdEnvironment() {
+    QStringList list;
+    auto msg = QDBusMessage::createMethodCall(QStringLiteral("org.freedesktop.systemd1"),
+                                              QStringLiteral("/org/freedesktop/systemd1"),
+                                              QStringLiteral("org.freedesktop.DBus.Properties"),
+                                              QStringLiteral("Get"));
+    msg << QStringLiteral("org.freedesktop.systemd1.Manager") << QStringLiteral("Environment");
+    auto reply = QDBusConnection::sessionBus().call(msg);
+    if (reply.type() == QDBusMessage::ErrorMessage) {
+        return std::nullopt;
+    }
+
+    // Make sure the returned type is correct.
+    auto arguments = reply.arguments();
+    if (arguments.isEmpty() || arguments[0].userType() != qMetaTypeId<QDBusVariant>()) {
+        return std::nullopt;
+    }
+    auto variant = qdbus_cast<QVariant>(arguments[0]);
+    if (variant.type() != QVariant::StringList) {
+        return std::nullopt;
+    }
+
+    return variant.toStringList();
+}
+
+// Import systemd user environment.
+//
+// Systemd read ~/.config/environment.d which applies to all systemd user unit.
+// But it won't work if plasma is not started by systemd.
+void importSystemdEnvrionment() {
+    auto environment = getSystemdEnvironment();
+    if (!environment) {
+        return;
+    }
+
+    for (auto &envString : environment.value()) {
+        const auto env = envString.toLocal8Bit();
+        const int idx = env.indexOf('=');
+        if (Q_UNLIKELY(idx <= 0)) {
+            continue;
+        }
+
+        const auto name = env.left(idx);
+        if (isShellVariable(name) || isSessionVariable(name)) {
+            continue;
+        }
+        setEnvironmentVariable(name, env.mid(idx + 1));
+    }
+}
+
 // Source scripts found in <config locations>/plasma-workspace/env/*.sh
 // (where <config locations> correspond to the system and user's configuration
 // directory.
@@ -292,12 +359,43 @@ void cleanupX11()
     runSync(QStringLiteral("xprop"), {QStringLiteral("-root"), QStringLiteral("-remove"), QStringLiteral("KDE_SESSION_VERSION")});
 }
 
-// TODO: Check if Necessary
-void cleanupPlasmaEnvironment()
+void cleanupPlasmaEnvironment(const std::optional<QStringList> &oldSystemdEnvironment)
 {
     qunsetenv("KDE_FULL_SESSION");
     qunsetenv("KDE_SESSION_VERSION");
     qunsetenv("KDE_SESSION_UID");
+
+    if (!oldSystemdEnvironment) {
+        return;
+    }
+
+    auto currentEnv = getSystemdEnvironment();
+    if (!currentEnv) {
+        return;
+    }
+
+    QStringList vars;
+    for (auto &env : currentEnv.value()) {
+        const int idx = env.indexOf(QLatin1Char('='));
+        if (Q_UNLIKELY(idx <= 0)) {
+            continue;
+        }
+
+        vars.append(env.left(idx));
+    }
+
+    // According to systemd documentation:
+    // If a variable is listed in both, the variable is set after this method returns, i.e. the set list overrides the unset list.
+    // So this will effectively restore the state to the values in oldSystemdEnvironment.
+    QDBusMessage message = QDBusMessage::createMethodCall(QStringLiteral("org.freedesktop.systemd1"),
+                                                          QStringLiteral("/org/freedesktop/systemd1"),
+                                                          QStringLiteral("org.freedesktop.systemd1.Manager"),
+                                                          QStringLiteral("UnsetAndSetEnvironment"));
+    message.setArguments({vars, oldSystemdEnvironment.value()});
+
+    // The session program gonna quit soon, ensure the message is flushed.
+    auto reply = QDBusConnection::sessionBus().asyncCall(message);
+    reply.waitForFinished();
 }
 
 // kwin_wayland can possibly also start dbus-activated services which need env variables.

startkde/startplasma.h

@@ -23,6 +23,7 @@
 #include "config-startplasma.h"
 #include "kcheckrunning/kcheckrunning.h"
 #include <ksplashinterface.h>
+#include <optional>
 
 extern QTextStream out;
 
@@ -34,9 +35,11 @@ void messageBox(const QString &text);
 void createConfigDirectory();
 void runStartupConfig();
 void setupCursor(bool wayland);
+std::optional<QStringList> getSystemdEnvironment();
+void importSystemdEnvrionment();
 void runEnvironmentScripts();
 void setupPlasmaEnvironment();
-void cleanupPlasmaEnvironment();
+void cleanupPlasmaEnvironment(const std::optional<QStringList> &oldSystemdEnvironment);
 void cleanupX11();
 bool syncDBusEnvironment();
 void setupFontDpi();