commit 94fb16b7c69c5a1e14a3a068038fd7c952546b58
Author: Harald Sitter <sitter@kde.org>
Date: Wed Feb 20 14:32:38 2019 +0100
wip fix race on kcrash restarts
diff --git a/src/kdbusservice.cpp b/src/kdbusservice.cpp
index 35dfe36..c39f72d 100644
--- a/src/kdbusservice.cpp
+++ b/src/kdbusservice.cpp
@@ -2,6 +2,7 @@
Copyright (c) 2011 David Faure <faure@kde.org>
Copyright (c) 2011 Kevin Ottens <ervin@kde.org>
+ Copyright (c) 2019 Harald Sitter <sitter@kde.org>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
@@ -74,26 +75,45 @@ public:
int exitValue;
};
-KDBusService::KDBusService(StartupOptions options, QObject *parent)
- : QObject(parent), d(new KDBusServicePrivate)
-{
- new KDBusServiceAdaptor(this);
- new KDBusServiceExtensionsAdaptor(this);
- QDBusConnectionInterface *bus = nullptr;
+// Wraps a serviceName registration.
+class Registration : public QObject {
+ Q_OBJECT
+public:
+ Registration(KDBusServicePrivate *d_, KDBusService::StartupOptions options_)
+ : d(d_)
+ , options(options_)
+ {
+ if (!QDBusConnection::sessionBus().isConnected() || !(bus = QDBusConnection::sessionBus().interface())) {
+ d->errorMessage = QLatin1String("Session bus not found\n"
+ "To circumvent this problem try the following command (with Linux and bash)\n"
+ "export $(dbus-launch)");
+ } else {
+ generateServiceName();
+ }
+ }
- if (!QDBusConnection::sessionBus().isConnected() || !(bus = QDBusConnection::sessionBus().interface())) {
- d->errorMessage = QLatin1String("Session bus not found\n"
- "To circumvent this problem try the following command (with Linux and bash)\n"
- "export $(dbus-launch)");
+ void run() {
+ qDebug() << "dbus start";
+ if (bus) {
+ registerOnBus();
+ }
+
+ if (!d->registered && ((options & KDBusService::NoExitOnFailure) == 0)) {
+ qCritical() << d->errorMessage;
+ exit(1);
+ }
}
- if (bus) {
+ private:
+
+ void generateServiceName()
+ {
d->serviceName = d->generateServiceName();
- QString objectPath = QLatin1Char('/') + d->serviceName;
+ objectPath = QLatin1Char('/') + d->serviceName;
objectPath.replace(QLatin1Char('.'), QLatin1Char('/'));
objectPath.replace(QLatin1Char('-'), QLatin1Char('_')); // see spec change at https://bugs.freedesktop.org/show_bug.cgi?id=95129
- if (options & Multiple) {
+ if (options & KDBusService::Multiple) {
bool inSandbox = false;
if (!qEnvironmentVariableIsEmpty("XDG_RUNTIME_DIR")) {
inSandbox = QFileInfo::exists(QString::fromUtf8(qgetenv("XDG_RUNTIME_DIR")) + QLatin1String("/flatpak-info"));
@@ -105,57 +125,121 @@ KDBusService::KDBusService(StartupOptions options, QObject *parent)
d->serviceName += QLatin1Char('-') + QString::number(QCoreApplication::applicationPid());
}
}
+ }
+ void registerOnBus()
+ {
QDBusConnection::sessionBus().registerObject(QStringLiteral("/MainApplication"), QCoreApplication::instance(),
- QDBusConnection::ExportAllSlots |
- QDBusConnection::ExportScriptableProperties |
- QDBusConnection::ExportAdaptors);
+ QDBusConnection::ExportAllSlots |
+ QDBusConnection::ExportScriptableProperties |
+ QDBusConnection::ExportAdaptors);
QDBusConnection::sessionBus().registerObject(objectPath, this,
- QDBusConnection::ExportAdaptors);
+ QDBusConnection::ExportAdaptors);
+
+ qDebug() << "registered objects -> trying to register service";
+
+ attemptRegistration();
+ if (!d->registered && options & KDBusService::Unique) {
+ qDebug() << "failed to register or activate; let's wait a bit";
+
+ // If we got here the activation failed for whatever reason.
+ // This may be a timing issue if the previous instance crashed and
+ // this new instance is already attempt to claim the service name
+ // before DBus takes away the name from the defunct previous
+ // instance. To prevent this reace condition we'll wait a sensible
+ // amount of time for the service name to get lost and then try
+ // to claim it again.
+ // This notably happens with KCrash autostarts of Unique services.
+ waitForNameLost();
+
+ attemptRegistration();
+ }
+
+ if (d->registered) {
+ qDebug() << "registered weeh!";
+ if (QCoreApplication *app = QCoreApplication::instance()) {
+ connect(app, SIGNAL(aboutToQuit()), this, SLOT(unregister()));
+ }
+ }
+ }
+
+ void attemptRegistration()
+ {
+ qDebug() << Q_FUNC_INFO;
+ Q_ASSERT(!d->registered);
d->registered = bus->registerService(d->serviceName) == QDBusConnectionInterface::ServiceRegistered;
- if (!d->registered) {
- if (options & Unique) {
- // Already running so it's ok!
- QVariantMap platform_data;
- platform_data.insert(QStringLiteral("desktop-startup-id"), QString::fromUtf8(qgetenv("DESKTOP_STARTUP_ID")));
- if (QCoreApplication::arguments().count() > 1) {
- OrgKdeKDBusServiceInterface iface(d->serviceName, objectPath, QDBusConnection::sessionBus());
- iface.setTimeout(5 * 60 * 1000); // Application can take time to answer
- QDBusReply<int> reply = iface.CommandLine(QCoreApplication::arguments(), QDir::currentPath(), platform_data);
- if (reply.isValid()) {
- exit(reply.value());
- } else {
- d->errorMessage = reply.error().message();
- }
+ if (d->registered) {
+ return;
+ }
+
+ if (options & KDBusService::Unique) {
+ // Already running so it's ok!
+ QVariantMap platform_data;
+ platform_data.insert(QStringLiteral("desktop-startup-id"), QString::fromUtf8(qgetenv("DESKTOP_STARTUP_ID")));
+ if (QCoreApplication::arguments().count() > 1) {
+ OrgKdeKDBusServiceInterface iface(d->serviceName, objectPath, QDBusConnection::sessionBus());
+ iface.setTimeout(5 * 60 * 1000); // Application can take time to answer
+ QDBusReply<int> reply = iface.CommandLine(QCoreApplication::arguments(), QDir::currentPath(), platform_data);
+ if (reply.isValid()) {
+ exit(reply.value());
} else {
- OrgFreedesktopApplicationInterface iface(d->serviceName, objectPath, QDBusConnection::sessionBus());
- iface.setTimeout(5 * 60 * 1000); // Application can take time to answer
- QDBusReply<void> reply = iface.Activate(platform_data);
- if (reply.isValid()) {
- exit(0);
- } else {
- d->errorMessage = reply.error().message();
- }
+ d->errorMessage = reply.error().message();
}
} else {
- d->errorMessage = QLatin1String("Couldn't register name '")
- + d->serviceName
- + QLatin1String("' with DBUS - another process owns it already!");
+ OrgFreedesktopApplicationInterface iface(d->serviceName, objectPath, QDBusConnection::sessionBus());
+ iface.setTimeout(5 * 60 * 1000); // Application can take time to answer
+ QDBusReply<void> reply = iface.Activate(platform_data);
+ if (reply.isValid()) {
+ exit(0);
+ } else {
+ d->errorMessage = reply.error().message();
+ }
}
-
} else {
- if (QCoreApplication *app = QCoreApplication::instance()) {
- connect(app, SIGNAL(aboutToQuit()), this, SLOT(unregister()));
- }
+ d->errorMessage = QLatin1String("Couldn't register name '")
+ + d->serviceName
+ + QLatin1String("' with DBUS - another process owns it already!");
}
}
- if (!d->registered && ((options & NoExitOnFailure) == 0)) {
- qCritical() << d->errorMessage;
- exit(1);
+ void waitForNameLost()
+ {
+ bus->connection().connect(QStringLiteral("org.freedesktop.DBus"),
+ QStringLiteral("/org/freedesktop/DBus"),
+ QStringLiteral("org.freedesktop.DBus"),
+ QStringLiteral("NameLost"),
+ this,
+ SLOT(onNameLost(QString,QDBusMessage)));
+ QTimer quitTimer;
+ quitTimer.start(250);
+ connect(&quitTimer, &QTimer::timeout, &nameLostLoop, &QEventLoop::quit);
+ nameLostLoop.exec();
}
+
+ void onNameLost(const QString &name, QDBusMessage)
+ {
+ qDebug() << Q_FUNC_INFO << name;
+ // our name got free'd
+ nameLostLoop.quit();
+ }
+
+ QDBusConnectionInterface *bus = nullptr;
+ KDBusServicePrivate *d = nullptr;
+ KDBusService::StartupOptions options;
+ QEventLoop nameLostLoop;
+ QString objectPath;
+};
+
+KDBusService::KDBusService(StartupOptions options, QObject *parent)
+ : QObject(parent), d(new KDBusServicePrivate)
+{
+ new KDBusServiceAdaptor(this);
+ new KDBusServiceExtensionsAdaptor(this);
+
+ Registration registration(d, options);
+ registration.run();
}
KDBusService::~KDBusService()
@@ -240,3 +324,5 @@ int KDBusService::CommandLine(const QStringList &arguments, const QString &worki
// TODO (via hook) KStartupInfo::appStarted(platform_data.value("desktop-startup-id"))
return d->exitValue;
}
+
+#include "kdbusservice.moc"