Retrieve output from journald

Qt nowadays logs into journald in some setups, so retrieve the output
from there and put it into the application output pane.

Change-Id: Ia2199a1420e1d80541f2f455e242d0b473922125
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/plugins/projectexplorer/applicationlauncher.cpp

@@ -32,6 +32,9 @@
 #ifdef Q_OS_WIN
 #include "windebuginterface.h"
 #endif
+#ifdef WITH_JOURNALD
+#include "journaldwatcher.h"
+#endif
 
 #include <coreplugin/icore.h>
 
@@ -125,6 +128,10 @@ ApplicationLauncher::ApplicationLauncher(QObject *parent)
     connect(WinDebugInterface::instance(), SIGNAL(debugOutput(qint64,QString)),
             this, SLOT(checkDebugOutput(qint64,QString)));
 #endif
+#ifdef WITH_JOURNALD
+    connect(JournaldWatcher::instance(), &JournaldWatcher::journaldOutput,
+            this, &ApplicationLauncher::checkDebugOutput);
+#endif
 }
 
 ApplicationLauncher::~ApplicationLauncher()
@@ -277,13 +284,13 @@ void ApplicationLauncher::cannotRetrieveDebugOutput()
     disconnect(WinDebugInterface::instance(), 0, this, 0);
     emit appendMessage(msgWinCannotRetrieveDebuggingOutput(), Utils::ErrorMessageFormat);
 }
+#endif
 
 void ApplicationLauncher::checkDebugOutput(qint64 pid, const QString &message)
 {
     if (applicationPID() == pid)
         emit appendMessage(message, Utils::DebugFormat);
 }
-#endif
 
 void ApplicationLauncher::processDone(int exitCode, QProcess::ExitStatus status)
 {

src/plugins/projectexplorer/applicationlauncher.h

@@ -87,8 +87,8 @@ private slots:
     void readStandardError();
 #ifdef Q_OS_WIN
     void cannotRetrieveDebugOutput();
-    void checkDebugOutput(qint64 pid, const QString &message);
 #endif
+    void checkDebugOutput(qint64 pid, const QString &message);
     void processDone(int, QProcess::ExitStatus);
     void bringToForeground();
 

src/plugins/projectexplorer/journaldwatcher.cpp

@@ -0,0 +1,221 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://www.qt.io/licensing.  For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "journaldwatcher.h"
+
+#include <utils/algorithm.h>
+#include <utils/qtcassert.h>
+
+#include <QDebug>
+#include <QSocketNotifier>
+
+#include <systemd/sd-journal.h>
+
+namespace ProjectExplorer {
+
+JournaldWatcher *JournaldWatcher::m_instance = 0;
+
+namespace Internal {
+
+class JournaldWatcherPrivate
+{
+public:
+    JournaldWatcherPrivate() :
+        m_journalContext(0),
+        m_notifier(0)
+    { }
+
+    ~JournaldWatcherPrivate()
+    {
+        teardown();
+    }
+
+    bool setup();
+    void teardown();
+
+    JournaldWatcher::LogEntry retrieveEntry();
+
+    class SubscriberInformation {
+    public:
+        SubscriberInformation(QObject *sr, const JournaldWatcher::Subscription &sn) :
+            subscriber(sr), subscription(sn)
+        { }
+
+        QObject *subscriber;
+        JournaldWatcher::Subscription subscription;
+    };
+    QList<SubscriberInformation> m_subscriptions;
+
+    sd_journal *m_journalContext;
+    QSocketNotifier *m_notifier;
+};
+
+bool JournaldWatcherPrivate::setup()
+{
+    QTC_ASSERT(!m_journalContext, return false);
+    int r = sd_journal_open(&m_journalContext, 0);
+    if (r != 0)
+        return false;
+
+    r = sd_journal_seek_tail(m_journalContext);
+    if (r != 0)
+        return false;
+
+    // Work around https://bugs.freedesktop.org/show_bug.cgi?id=64614
+    sd_journal_previous(m_journalContext);
+
+    int fd = sd_journal_get_fd(m_journalContext);
+    if (fd < 0)
+        return false;
+
+    m_notifier = new QSocketNotifier(fd, QSocketNotifier::Read);
+    return true;
+}
+
+void JournaldWatcherPrivate::teardown()
+{
+    delete m_notifier;
+    m_notifier = 0;
+
+    if (m_journalContext) {
+        sd_journal_close(m_journalContext);
+        m_journalContext = 0;
+    }
+}
+
+JournaldWatcher::LogEntry JournaldWatcherPrivate::retrieveEntry()
+{
+    JournaldWatcher::LogEntry result;
+
+    // Advance:
+    int r = sd_journal_next(m_journalContext);
+    if (r == 0)
+        return result;
+
+    const void *rawData;
+    size_t length;
+    SD_JOURNAL_FOREACH_DATA(m_journalContext, rawData, length) {
+        QByteArray tmp = QByteArray::fromRawData(static_cast<const char *>(rawData), length);
+        int offset = tmp.indexOf('=');
+        if (offset < 0)
+            continue;
+        result.insert(tmp.left(offset), tmp.mid(offset + 1));
+    }
+
+    return result;
+}
+
+} // namespace Internal
+
+using namespace Internal;
+
+static JournaldWatcherPrivate *d = 0;
+
+JournaldWatcher::~JournaldWatcher()
+{
+    d->teardown();
+
+    m_instance = 0;
+
+    delete d;
+    d = 0;
+}
+
+JournaldWatcher *JournaldWatcher::instance()
+{
+    return m_instance;
+}
+
+bool JournaldWatcher::subscribe(QObject *subscriber, const Subscription &subscription)
+{
+    // Check that we do not have that subscriber yet:
+    int pos = Utils::indexOf(d->m_subscriptions,
+                             [subscriber](const JournaldWatcherPrivate::SubscriberInformation &info) {
+                                 return info.subscriber == subscriber;
+                             });
+    QTC_ASSERT(pos >= 0, return false);
+
+    d->m_subscriptions.append(JournaldWatcherPrivate::SubscriberInformation(subscriber, subscription));
+    connect(subscriber, &QObject::destroyed, m_instance, &JournaldWatcher::unsubscribe);
+
+    return true;
+}
+
+void JournaldWatcher::unsubscribe(QObject *subscriber)
+{
+    int pos = Utils::indexOf(d->m_subscriptions,
+                            [subscriber](const JournaldWatcherPrivate::SubscriberInformation &info) {
+                                return info.subscriber == subscriber;
+                            });
+    if (pos < 0)
+        return;
+
+    d->m_subscriptions.removeAt(pos);
+}
+
+JournaldWatcher::JournaldWatcher()
+{
+    QTC_ASSERT(!m_instance, return);
+
+    d = new JournaldWatcherPrivate;
+    m_instance = this;
+
+    if (!d->setup())
+        d->teardown();
+    else
+        connect(d->m_notifier, &QSocketNotifier::activated, m_instance, &JournaldWatcher::handleEntry);
+    m_instance->handleEntry(); // advance to the end of file...
+}
+
+void JournaldWatcher::handleEntry()
+{
+    // process events:
+    if (!d->m_notifier || sd_journal_process(d->m_journalContext) == SD_JOURNAL_NOP)
+        return;
+
+    LogEntry logEntry;
+    forever {
+        logEntry = d->retrieveEntry();
+        if (logEntry.isEmpty())
+            break;
+
+        foreach (const JournaldWatcherPrivate::SubscriberInformation &info, d->m_subscriptions)
+            info.subscription(logEntry);
+
+        QByteArray tmp = logEntry.value(QByteArrayLiteral("_PID"));
+        quint64 pid = tmp.isEmpty() ? 0 : QString::fromLatin1(tmp).toInt();
+
+        QString message = QString::fromUtf8(logEntry.value(QByteArrayLiteral("MESSAGE")));
+
+        emit journaldOutput(pid, message);
+    }
+}
+
+} // namespace ProjectExplorer

src/plugins/projectexplorer/journaldwatcher.h

@@ -0,0 +1,72 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://www.qt.io/licensing.  For further information
+** use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#ifndef JOURNALDWATCHER_H
+#define JOURNALDWATCHER_H
+
+#include <QObject>
+
+#include <functional>
+
+namespace ProjectExplorer {
+
+class ProjectExplorerPlugin;
+
+class JournaldWatcher : public QObject
+{
+    Q_OBJECT
+
+public:
+    typedef QMap<QByteArray, QByteArray> LogEntry;
+    typedef std::function<void(LogEntry)> Subscription;
+
+    ~JournaldWatcher();
+
+    static JournaldWatcher *instance();
+
+    static bool subscribe(QObject *subscriber, const Subscription &subscription);
+    static void unsubscribe(QObject *subscriber);
+
+signals:
+    void journaldOutput(quint64 pid, const QString &message);
+
+private:
+    JournaldWatcher();
+
+    void handleEntry();
+
+    static JournaldWatcher *m_instance;
+
+    friend class ProjectExplorerPlugin;
+};
+
+} // namespace ProjectExplorer
+
+#endif // JOURNALDWATCHER_H

src/plugins/projectexplorer/projectexplorer.cpp

@@ -36,6 +36,9 @@
 #include "deployablefile.h"
 #include "deployconfiguration.h"
 #include "gcctoolchainfactories.h"
+#ifdef WITH_JOURNALD
+#include "journaldwatcher.h"
+#endif
 #include "jsonwizard/jsonwizardfactory.h"
 #include "jsonwizard/jsonwizardgeneratorfactory.h"
 #include "jsonwizard/jsonwizardpagefactory_p.h"
@@ -284,6 +287,9 @@ public:
     QStringList m_arguments;
     QList<ProjectPanelFactory *> m_panelFactories;
     QString m_renameFileError;
+#ifdef WITH_JOURNALD
+    JournaldWatcher *m_journalWatcher;
+#endif
 };
 
 ProjectExplorerPluginPrivate::ProjectExplorerPluginPrivate() :
@@ -293,6 +299,9 @@ ProjectExplorerPluginPrivate::ProjectExplorerPluginPrivate() :
     m_kitManager(0),
     m_toolChainManager(0),
     m_shuttingDown(false)
+#ifdef WITH_JOURNALD
+    , m_journalWatcher(0)
+#endif
 {
 }
 
@@ -331,6 +340,9 @@ ProjectExplorerPlugin::~ProjectExplorerPlugin()
     // Force sequence of deletion:
     delete dd->m_kitManager; // remove all the profile information
     delete dd->m_toolChainManager;
+#ifdef WITH_JOURNALD
+    delete dd->m_journalWatcher;
+#endif
     ProjectPanelFactory::destroyFactories();
     delete dd;
 }
@@ -354,6 +366,10 @@ bool ProjectExplorerPlugin::initialize(const QStringList &arguments, QString *er
 
     addAutoReleasedObject(new DeviceManager);
 
+#ifdef WITH_JOURNALD
+    dd->m_journalWatcher = new JournaldWatcher;
+#endif
+
     // Add ToolChainFactories:
 #ifdef Q_OS_WIN
     addAutoReleasedObject(new WinDebugInterface);

src/plugins/projectexplorer/projectexplorer.pro

@@ -333,6 +333,13 @@ equals(TEST, 1) {
         outputparser_test.h
 }
 
+journald {
+    SOURCES += journaldwatcher.cpp
+    HEADERS += journaldwatcher.h
+    DEFINES += WITH_JOURNALD
+    LIBS += -lsystemd
+}
+
 macx:LIBS += -framework Carbon
 
 RESOURCES += projectexplorer.qrc