Avoid conflicts on Linux desktops by using a non-standard Wayland socket

If not specified differently via command line option or $WAYLAND_DISPLAY,
the AM would just rely on libwayland to pick a name for its Wayland socket.
The problem here is that some desktop environments would see "wayland-0"
(the first compositor registered) and think that they are running in
Wayland mode and consequentially start client applications on this
compositor.

The default for the AM is now "qtam-wayland-0".

Change-Id: I508ac8fb051735dc64de35ea8dfc44491786c7d7
Reviewed-by: Dominik Holland <dominik.holland@pelagicore.com>

2 files changed, 19 insertions, 4 deletions

diff --git a/src/main-lib/defaultconfiguration.cpp b/src/main-lib/defaultconfiguration.cpp
index c79da1d7..6ee6b2e0 100644
--- a/src/main-lib/defaultconfiguration.cpp
+++ b/src/main-lib/defaultconfiguration.cpp
@@ -42,6 +42,7 @@
 
 #include <QFileInfo>
 #include <QCoreApplication>
+#include <QFile>
 #include <QDebug>
 
 #include <QtAppManCommon/logging.h>
@@ -447,7 +448,21 @@ int DefaultConfiguration::quickLaunchRuntimesPerContainer() const
 
 QString DefaultConfiguration::waylandSocketName() const
 {
-    return value<QString>("wayland-socket-name");
+    const QString socket = m_clp.value(qSL("wayland-socket-name")); // get the default value
+    if (!socket.isEmpty())
+        return socket;
+
+    const char *envName = "WAYLAND_DISPLAY";
+    if (qEnvironmentVariableIsSet(envName))
+        return qEnvironmentVariable(envName);
+
+    const QString lockPattern = qEnvironmentVariable("XDG_RUNTIME_DIR") + qSL("/qtam-wayland-%1.lock");
+    for (int i = 0; i < 32; ++i) {
+        QFile lock(lockPattern.arg(i));
+        if (lock.open(QIODevice::ReadWrite | QIODevice::NewOnly))
+            return qSL("qtam-wayland-%1").arg(i);
+    }
+    return QString();
 }
 
 QString DefaultConfiguration::telnetAddress() const
diff --git a/src/window-lib/windowmanager.cpp b/src/window-lib/windowmanager.cpp
index 19297bdd..096db273 100644
--- a/src/window-lib/windowmanager.cpp
+++ b/src/window-lib/windowmanager.cpp
@@ -570,7 +570,7 @@ void WindowManager::registerCompositorView(QQuickWindow *view)
 
             // export the actual socket name for our child processes.
             qputenv("WAYLAND_DISPLAY", d->waylandCompositor->socketName());
-            qCDebug(LogGraphics).nospace() << "WindowManager: running in Wayland mode [socket: "
+            qCInfo(LogGraphics).nospace() << "WindowManager: running in Wayland mode [socket: "
                                            << d->waylandCompositor->socketName() << "]";
             ApplicationManager::instance()->setWindowManagerCompositorReady(true);
         } else {
@@ -578,11 +578,11 @@ void WindowManager::registerCompositorView(QQuickWindow *view)
         }
     } else {
         if (!once)
-            qCDebug(LogGraphics) << "WindowManager: running in single-process mode [forced at run-time]";
+            qCInfo(LogGraphics) << "WindowManager: running in single-process mode [forced at run-time]";
     }
 #else
     if (!once)
-        qCDebug(LogGraphics) << "WindowManager: running in single-process mode [forced at compile-time]";
+        qCInfo(LogGraphics) << "WindowManager: running in single-process mode [forced at compile-time]";
 #endif
     emit compositorViewRegistered(view);