add perf query interface and untangle it from recordpage

moving the query part of the recordpage into its own class will make
implementing remote recording much easier

Author: lievenhey

src/CMakeLists.txt

@@ -53,6 +53,7 @@ set(HOTSPOT_SRCS
     initiallystoppedprocess.cpp
     perfcontrolfifowrapper.cpp
     errnoutil.cpp
+    recordhost.cpp
     # ui files:
     mainwindow.ui
     aboutdialog.ui
@@ -73,6 +74,7 @@ set(HOTSPOT_SRCS
     callgraphsettingspage.ui
     frequencypage.ui
     sourcepathsettings.ui
+    perfsettingspage.ui
     # resources:
     resources.qrc
 )

src/jobtracker.h

@@ -0,0 +1,63 @@
+/*
+    SPDX-FileCopyrightText: Milian Wolff <[email protected]>
+    SPDX-FileCopyrightText: 2022 Klarälvdalens Datakonsult AB, a KDAB Group company, [email protected]
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include <ThreadWeaver/ThreadWeaver>
+#include <QObject>
+#include <QPointer>
+
+class JobTracker
+{
+public:
+    explicit JobTracker(QObject* context)
+        : m_context(context)
+    {
+    }
+
+    bool isJobRunning() const
+    {
+        return m_context && m_isRunning;
+    }
+
+    template<typename Job, typename SetData>
+    void startJob(Job&& job, SetData&& setData)
+    {
+        using namespace ThreadWeaver;
+        const auto jobId = ++m_currentJobId;
+        auto jobCancelled = [context = m_context, jobId, currentJobId = &m_currentJobId]() {
+            return !context || jobId != (*currentJobId);
+        };
+        auto maybeSetData = [jobCancelled, setData = std::forward<SetData>(setData),
+                             isRunning = &m_isRunning](auto&& results) {
+            if (!jobCancelled()) {
+                setData(std::forward<decltype(results)>(results));
+                *isRunning = false;
+            }
+        };
+
+        m_isRunning = true;
+        stream() << make_job([context = m_context, job = std::forward<Job>(job), maybeSetData = std::move(maybeSetData),
+                              jobCancelled = std::move(jobCancelled)]() mutable {
+            auto results = job(jobCancelled);
+            if (jobCancelled())
+                return;
+
+            QMetaObject::invokeMethod(
+                context.data(),
+                [results = std::move(results), maybeSetData = std::move(maybeSetData)]() mutable {
+                    maybeSetData(std::move(results));
+                },
+                Qt::QueuedConnection);
+        });
+    }
+
+private:
+    QPointer<QObject> m_context;
+    std::atomic<uint> m_currentJobId;
+    bool m_isRunning = false;
+};

src/perfrecord.cpp

@@ -8,6 +8,8 @@
 
 #include "perfrecord.h"
 
+#include "recordhost.h"
+
 #include <QDebug>
 #include <QDir>
 #include <QFileInfo>
@@ -19,20 +21,13 @@
 #include <csignal>
 #include <unistd.h>
 
-#include <KUser>
-
 #include <kwindowsystem_version.h>
 #if KWINDOWSYSTEM_VERSION >= QT_VERSION_CHECK(5, 101, 0)
 #include <KX11Extras>
 #else
 #include <KWindowSystem>
 #endif
 
-#include <hotspot-config.h>
-
-#include <fstream>
-#include <sys/stat.h>
-
 namespace {
 void createOutputFile(const QString& outputPath)
 {
@@ -44,17 +39,11 @@ void createOutputFile(const QString& outputPath)
     QFile::rename(outputPath, bakPath);
     QFile(outputPath).open(QIODevice::WriteOnly);
 }
-
-QString findPkexec()
-{
-    return QStandardPaths::findExecutable(QStringLiteral("pkexec"));
-}
 }
 
-PerfRecord::PerfRecord(QObject* parent)
+PerfRecord::PerfRecord(const RecordHost *host, QObject* parent)
     : QObject(parent)
-    , m_perfRecordProcess(nullptr)
-    , m_userTerminated(false)
+    , m_host(host)
 {
     connect(&m_perfControlFifo, &PerfControlFifoWrapper::started, this,
             [this]() { m_targetProcessForPrivilegedPerf.continueStoppedProcess(); });
@@ -72,38 +61,6 @@ PerfRecord::~PerfRecord()
     }
 }
 
-static bool privsAlreadyElevated()
-{
-    auto readSysctl = [](const char* path) {
-        std::ifstream ifs {path};
-        int i = std::numeric_limits<int>::min();
-        if (ifs) {
-            ifs >> i;
-        }
-        return i;
-    };
-
-    bool isElevated = readSysctl("/proc/sys/kernel/kptr_restrict") == 0;
-    if (!isElevated) {
-        return false;
-    }
-
-    isElevated = readSysctl("/proc/sys/kernel/perf_event_paranoid") == -1;
-    if (!isElevated) {
-        return false;
-    }
-
-    auto checkPerms = [](const char* path) {
-        const mode_t required = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH; // 755
-        struct stat buf;
-        return stat(path, &buf) == 0 && ((buf.st_mode & 07777) & required) == required;
-    };
-    static const auto paths = {"/sys/kernel/debug", "/sys/kernel/debug/tracing"};
-    isElevated = std::all_of(paths.begin(), paths.end(), checkPerms);
-
-    return isElevated;
-}
-
 bool PerfRecord::runPerf(bool elevatePrivileges, const QStringList& perfOptions, const QString& outputPath,
                          const QString& workingDirectory)
 {
@@ -176,14 +133,14 @@ bool PerfRecord::runPerf(bool elevatePrivileges, const QStringList& perfOptions,
     perfCommand += perfOptions;
 
     if (elevatePrivileges) {
-        const auto pkexec = findPkexec();
+        const auto pkexec = m_host->pkexecBinaryPath();
         if (pkexec.isEmpty()) {
             emit recordingFailed(tr("The pkexec utility was not found, cannot elevate privileges."));
             return false;
         }
 
         auto options = QStringList();
-        options.append(perfBinaryPath());
+        options.append(m_host->perfBinaryPath());
         options += perfCommand;
 
         if (!m_perfControlFifo.open()) {
@@ -198,7 +155,7 @@ bool PerfRecord::runPerf(bool elevatePrivileges, const QStringList& perfOptions,
 
         m_perfRecordProcess->start(pkexec, options);
     } else {
-        m_perfRecordProcess->start(perfBinaryPath(), perfCommand);
+        m_perfRecordProcess->start(m_host->perfBinaryPath(), perfCommand);
     }
 
     return true;
@@ -295,106 +252,13 @@ void PerfRecord::sendInput(const QByteArray& input)
     m_perfRecordProcess->write(input);
 }
 
-QString PerfRecord::currentUsername()
-{
-    return KUser().loginName();
-}
-
-bool PerfRecord::canTrace(const QString& path)
-{
-    const auto info = QFileInfo(QLatin1String("/sys/kernel/debug/tracing/") + path);
-    if (!info.isDir() || !info.isReadable()) {
-        return false;
-    }
-    QFile paranoid(QStringLiteral("/proc/sys/kernel/perf_event_paranoid"));
-    return paranoid.open(QIODevice::ReadOnly) && paranoid.readAll().trimmed() == "-1";
-}
-
-static QByteArray perfOutput(const QStringList& arguments)
-{
-    QProcess process;
-
-    auto reportError = [&]() {
-        qWarning() << "Failed to run perf" << process.arguments() << process.error() << process.errorString()
-                   << process.readAllStandardError();
-    };
-
-    QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
-    env.insert(QStringLiteral("LANG"), QStringLiteral("C"));
-    process.setProcessEnvironment(env);
-
-    QObject::connect(&process, &QProcess::errorOccurred, &process, reportError);
-    process.start(PerfRecord::perfBinaryPath(), arguments);
-    if (!process.waitForFinished(1000) || process.exitCode() != 0)
-        reportError();
-    return process.readAllStandardOutput();
-}
-
-static QByteArray perfRecordHelp()
-{
-    static const QByteArray recordHelp = []() {
-        static QByteArray help = perfOutput({QStringLiteral("record"), QStringLiteral("--help")});
-        if (help.isEmpty()) {
-            // no man page installed, assume the best
-            help = "--sample-cpu --switch-events";
-        }
-        return help;
-    }();
-    return recordHelp;
-}
-
-static QByteArray perfBuildOptions()
-{
-    static const QByteArray buildOptions = perfOutput({QStringLiteral("version"), QStringLiteral("--build-options")});
-    return buildOptions;
-}
-
-bool PerfRecord::canProfileOffCpu()
-{
-    return canTrace(QStringLiteral("events/sched/sched_switch"));
-}
-
 QStringList PerfRecord::offCpuProfilingOptions()
 {
     return {QStringLiteral("--switch-events"), QStringLiteral("--event"), QStringLiteral("sched:sched_switch")};
 }
 
-bool PerfRecord::canSampleCpu()
-{
-    return perfRecordHelp().contains("--sample-cpu");
-}
-
-bool PerfRecord::canSwitchEvents()
-{
-    return perfRecordHelp().contains("--switch-events");
-}
-
-bool PerfRecord::canUseAio()
-{
-    return perfBuildOptions().contains("aio: [ on  ]");
-}
-
-bool PerfRecord::canCompress()
-{
-    return Zstd_FOUND && perfBuildOptions().contains("zstd: [ on  ]");
-}
-
-bool PerfRecord::canElevatePrivileges()
-{
-    return !findPkexec().isEmpty();
-}
-
-QString PerfRecord::perfBinaryPath()
-{
-    return QStandardPaths::findExecutable(QStringLiteral("perf"));
-}
-
-bool PerfRecord::isPerfInstalled()
-{
-    return !perfBinaryPath().isEmpty();
-}
-
-bool PerfRecord::actuallyElevatePrivileges(bool elevatePrivileges)
+bool PerfRecord::actuallyElevatePrivileges(bool elevatePrivileges) const
 {
-    return elevatePrivileges && canElevatePrivileges() && geteuid() != 0 && !privsAlreadyElevated();
+    const auto capabilities = m_host->perfCapabilities();
+    return elevatePrivileges && capabilities.canElevatePrivileges && !capabilities.privilegesAlreadyElevated;
 }

src/perfrecord.h

@@ -15,12 +15,13 @@
 #include <QPointer>
 
 class QProcess;
+class RecordHost;
 
 class PerfRecord : public QObject
 {
     Q_OBJECT
 public:
-    explicit PerfRecord(QObject* parent = nullptr);
+    explicit PerfRecord(const RecordHost *host, QObject* parent = nullptr);
     ~PerfRecord();
 
     void record(const QStringList& perfOptions, const QString& outputPath, bool elevatePrivileges,
@@ -33,21 +34,8 @@ class PerfRecord : public QObject
     void stopRecording();
     void sendInput(const QByteArray& input);
 
-    static QString currentUsername();
-
-    static bool canTrace(const QString& path);
-    static bool canProfileOffCpu();
-    static bool canSampleCpu();
-    static bool canSwitchEvents();
-    static bool canUseAio();
-    static bool canCompress();
-    static bool canElevatePrivileges();
-
     static QStringList offCpuProfilingOptions();
 
-    static QString perfBinaryPath();
-    static bool isPerfInstalled();
-
 signals:
     void recordingStarted(const QString& perfBinary, const QStringList& arguments);
     void recordingFinished(const QString& fileLocation);
@@ -56,13 +44,14 @@ class PerfRecord : public QObject
     void debuggeeCrashed();
 
 private:
+    const RecordHost *m_host = nullptr;
     QPointer<QProcess> m_perfRecordProcess;
     InitiallyStoppedProcess m_targetProcessForPrivilegedPerf;
     PerfControlFifoWrapper m_perfControlFifo;
     QString m_outputPath;
-    bool m_userTerminated;
+    bool m_userTerminated = false;
 
-    static bool actuallyElevatePrivileges(bool elevatePrivileges);
+    bool actuallyElevatePrivileges(bool elevatePrivileges) const;
 
     bool runPerf(bool elevatePrivileges, const QStringList& perfOptions, const QString& outputPath,
                  const QString& workingDirectory = QString());

src/perfsettingspage.ui

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>PerfSettingsPage</class>
+ <widget class="QWidget" name="PerfSettingsPage">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>300</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QFormLayout" name="formLayout">
+   <item row="1" column="0">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>Perf Binary:</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="1">
+    <widget class="KUrlRequester" name="perfPathEdit"/>
+   </item>
+  </layout>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>KUrlRequester</class>
+   <extends>QWidget</extends>
+   <header>kurlrequester.h</header>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections/>
+</ui>