System-wide single instance for all users, fix shadowsocks#451

README.md

@@ -19,20 +19,11 @@ Features
 - Use multiple profiles simultaneously
 - `config.ini` is located under `~/.config/shadowsocks-qt5/` on \*nix platforms, or under the application's directory on Windows.
 
-Note
-----
-
-If `ss-qt5` crashes and the **only one instance** mode is checked,
-you may need to manually delete `/tmp/qipc_sharedmemory_ShadowsocksQt*`
-and `/tmp/qipc_systemsem_ShadowsocksQt*`.
-Otherwise, `ss-qt5` will complain that another instance is already running.
-Run `ss-qt5` again is also expected to work.
-
 LICENSE
 -------
 
 ![](http://www.gnu.org/graphics/lgplv3-147x51.png)
 
-Copyright © 2014-2016 Symeon Huang
+Copyright © 2014-2017 Symeon Huang
 
 This project is licensed under version 3 of the GNU Lesser General Public License.

shadowsocks-qt5.pro

@@ -11,7 +11,7 @@ CONFIG    += c++11
 
 TARGET     = ss-qt5
 TEMPLATE   = app
-VERSION    = 2.8.1
+VERSION    = 2.9.0
 DEFINES   += APP_VERSION=\\\"$$VERSION\\\"
 
 include(src/ss-qt5.pri)

src/main.cpp

@@ -3,7 +3,6 @@
 #include <QLibraryInfo>
 #include <QLocale>
 #include <QMessageBox>
-#include <QSharedMemory>
 #include <QDebug>
 #include <QDir>
 #include <QCommandLineParser>
@@ -15,23 +14,17 @@ MainWindow *mainWindow = nullptr;
 
 static void onSignalRecv(int sig)
 {
-#ifdef Q_OS_UNIX
-    if (sig == SIGUSR1) {
-        if (mainWindow) {
-            mainWindow->show();
-        }
+    if (sig == SIGINT || sig == SIGTERM) {
+        qApp->quit();
+    } else {
+        qWarning("Unhandled signal %d", sig);
     }
-#endif
-    if (sig == SIGINT || sig == SIGTERM) qApp->quit();
 }
 
 void setupApplication(QApplication &a)
 {
     signal(SIGINT, onSignalRecv);
     signal(SIGTERM, onSignalRecv);
-#ifdef Q_OS_UNIX
-    signal(SIGUSR1, onSignalRecv);
-#endif
 
     a.setApplicationName(QString("shadowsocks-qt5"));
     a.setApplicationDisplayName(QString("Shadowsocks-Qt5"));

src/mainwindow.cpp

@@ -21,7 +21,8 @@
 MainWindow::MainWindow(ConfigHelper *confHelper, QWidget *parent) :
     QMainWindow(parent),
     ui(new Ui::MainWindow),
-    configHelper(confHelper)
+    configHelper(confHelper),
+    instanceRunning(false)
 {
     Q_ASSERT(configHelper);
 
@@ -448,7 +449,7 @@ void MainWindow::onAbout()
     QString text = QString("<h1>Shadowsocks-Qt5</h1><p><b>Version %1</b><br />"
             "Using libQtShadowsocks %2<br />"
             "Using Botan %3.%4.%5</p>"
-            "<p>Copyright © 2014-2016 Symeon Huang "
+            "<p>Copyright © 2014-2017 Symeon Huang "
             "(<a href='https://twitter.com/librehat'>"
             "@librehat</a>)</p>"
             "<p>License: <a href='http://www.gnu.org/licenses/lgpl.html'>"
@@ -558,31 +559,28 @@ bool MainWindow::isInstanceRunning() const
 
 void MainWindow::initSingleInstance()
 {
-    instanceRunning = false;
-
-    QString username = qgetenv("USER");
-    if (username.isEmpty()) {
-        username = qgetenv("USERNAME");
-    }
-
-    QString serverName = QCoreApplication::applicationName() + "_" + username;
+    const QString serverName = QCoreApplication::applicationName();
     QLocalSocket socket;
     socket.connectToServer(serverName);
     if (socket.waitForConnected(500)) {
         instanceRunning = true;
         if (configHelper->isOnlyOneInstance()) {
-            qWarning() << "A instance from the same user is already running";
+            qWarning() << "An instance of ss-qt5 is already running";
         }
-        socket.write(serverName.toUtf8());
+        QByteArray username = qgetenv("USER");
+        if (username.isEmpty()) {
+            username = qgetenv("USERNAME");
+        }
+        socket.write(username);
         socket.waitForBytesWritten();
         return;
     }
 
-    /* Cann't connect to server, indicating it's the first instance of the user */
+    /* Can't connect to server, indicating it's the first instance of the user */
     instanceServer = new QLocalServer(this);
-    instanceServer->setSocketOptions(QLocalServer::UserAccessOption);
+    instanceServer->setSocketOptions(QLocalServer::WorldAccessOption);
     connect(instanceServer, &QLocalServer::newConnection,
-            this,&MainWindow::onSingleInstanceConnect);
+            this, &MainWindow::onSingleInstanceConnect);
     if (instanceServer->listen(serverName)) {
         /* Remove server in case of crashes */
         if (instanceServer->serverError() == QAbstractSocket::AddressInUseError &&
@@ -601,16 +599,18 @@ void MainWindow::onSingleInstanceConnect()
     }
 
     if (socket->waitForReadyRead(1000)) {
-        QString username = qgetenv("USER");
+        QByteArray username = qgetenv("USER");
         if (username.isEmpty()) {
             username = qgetenv("USERNAME");
         }
 
-        QByteArray byteArray = socket->readAll();
-        QString magic(byteArray);
-        if (magic == QCoreApplication::applicationName() + "_" + username) {
+        QByteArray recvUsername = socket->readAll();
+        if (recvUsername == username) {
+            // Only show the window if it's the same user
             show();
+        } else {
+            qWarning("Another user is trying to run another instance of ss-qt5");
         }
     }
-    delete socket;
+    socket->deleteLater();
 }