File indexing completed on 2024-12-08 10:52:35

 /*
     SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
     SPDX-FileCopyrightText: 2019-2022 Harald Sitter <sitter@kde.org>
 */
 
 #include <QCoreApplication>
 #include <QDebug>
 #include <QFile>
 #include <QJsonDocument>
 #include <QLibraryInfo>
 #include <QPluginLoader>
 #include <QProcess>
 #include <QScopeGuard>
 #include <QSettings>
 #include <QStandardPaths>
 
 #include <cerrno>
 #include <chrono>
 #include <memory>
 #include <tuple>
 #include <utility>
 
 #include <poll.h>
 #include <systemd/sd-daemon.h>
 #include <unistd.h>
 
 #include "../coredump.h"
 #include "../metadata.h"
 #include "../socket.h"
 #include "DumpTruckInterface.h"
 
 using namespace std::chrono_literals;
 
 static QString drkonqiExe()
 {
     // Borrowed from kcrash.cpp
     static QStringList paths = QFile::decodeName(qgetenv("LIBEXEC_PATH")).split(QLatin1Char(':'), Qt::SkipEmptyParts)
         + QStringList{
             QCoreApplication::applicationDirPath(), // then look where our application binary is located
             QLibraryInfo::location(QLibraryInfo::LibraryExecutablesPath), // look where libexec path is (can be set in qt.conf)
             QFile::decodeName(KDE_INSTALL_FULL_LIBEXECDIR), // look at our installation location
         };
     static QString exec = QStandardPaths::findExecutable(QStringLiteral("drkonqi"), paths);
     return exec;
 }
 
 using ArgumentsPidTuple = std::tuple<QStringList, bool>;
 
 static ArgumentsPidTuple metadataArguments(const Coredump &dump, const QString &metadataPath)
 {
     QStringList arguments;
     bool foundPID = false;
 
     // Parse the metadata file. Ideally we'd should even stop passing a gazillion options
     // and instead rely on this file, then drkonqi
     // would also be in charge of removing it instead of us here.
     QSettings metadata(metadataPath, QSettings::IniFormat);
     metadata.beginGroup(QStringLiteral("KCrash"));
     const QStringList keys = metadata.allKeys();
     for (const QString &key : keys) {
         const QString value = metadata.value(key).toString();
 
         if (key == QLatin1String("exe")) {
             if (value.endsWith(QStringLiteral("/drkonqi"))) {
                 qWarning() << "drkonqi crashed, we aren't going to invoke it again, we might be the reason it crashd :O";
                 return {};
             }
             if (value != dump.exe) {
                 qWarning() << "the exe in the metadata file doesn't match the exe in the journal entry! aborting" << value << dump.exe;
                 return {};
             }
             // exe purely exists for our benefit, don't forward it to drkonqi.
             continue;
         }
 
         if (key == QLatin1String("pid")) {
             foundPID = true;
         }
 
         arguments << QStringLiteral("--%1").arg(key);
         if (value != QLatin1String("true") && value != QLatin1String("false")) { // not a bool value, append as arg
             arguments << value;
         }
     }
     metadata.endGroup();
 
     return {arguments, foundPID};
 }
 
 static ArgumentsPidTuple includeAllArguments(const Coredump &dump)
 {
     // Synthesize drkonqi arguments from the dump alone, this has limited functionality and is meant for use with
     // non-KDE apps.
     QStringList arguments;
     arguments << QStringLiteral("--signal") << QString::fromUtf8(dump.m_rawData.value(QByteArrayLiteral("COREDUMP_SIGNAL")));
     arguments << QStringLiteral("--pid") << QString::fromUtf8(dump.m_rawData.value(QByteArrayLiteral("COREDUMP_PID")));
     arguments << QStringLiteral("--restarted"); // Cannot restart foreign apps!
     return {arguments, true};
 }
 
 static ArgumentsPidTuple includeKWinWaylandArguments(const Coredump &dump)
 {
     auto [arguments, foundPID] = includeAllArguments(dump);
     arguments << QStringLiteral("--bugaddress") << QStringLiteral("submit@bugs.kde.org") << QStringLiteral("--appname") << dump.exe;
     return {arguments, foundPID};
 }
 
 static bool tryDrkonqi(const Coredump &dump)
 {
     const QString metadataPath = Metadata::resolveMetadataPath(dump.pid);
     const QString configFile = QStandardPaths::locate(QStandardPaths::ConfigLocation, QStringLiteral("drkonqirc"));
 
     // Arm removal. If we return early this will ensure clean up, otherwise we dismiss it later
     auto deleteFile = qScopeGuard([metadataPath] {
         QFile::remove(metadataPath);
     });
 
     if (qEnvironmentVariableIsSet("KDE_DEBUG")) {
         qWarning() << "KDE_DEBUG set. Not invoking DrKonqi.";
         return false;
     }
 
     if (drkonqiExe().isEmpty()) {
         qWarning() << "Couldn't find drkonqi exe";
         return false;
     }
 
     QStringList arguments;
     bool foundPID = false;
 
     if (!metadataPath.isEmpty()) {
         // A KDE app crash has metadata, build arguments from that
         std::tie(arguments, foundPID) = metadataArguments(dump, metadataPath);
     } else if (dump.exe.endsWith(QLatin1String("/kwin_wayland"))) {
         // When the compositor goes down it may not have time to store metadata, in that case we'll fake them.
         std::tie(arguments, foundPID) = includeKWinWaylandArguments(dump);
     } else if (QSettings(configFile, QSettings::IniFormat).value(QStringLiteral("IncludeAll")).toBool()) {
         // Handle non-KDE apps when in IncludeAll mode.
         std::tie(arguments, foundPID) = includeAllArguments(dump);
     } else {
         return false;
     }
 
     if (arguments.isEmpty() || !foundPID) {
         // There is a chance that somehow the metadata file writing failed or is incomplete. Do some trivial
         // checks to catch and ignore such cases. Otherwise we risk drkonqi crashing due to internally failed
         // assertions.
         qWarning() << "Failed to read metadata from crash" << arguments << foundPID;
         return false;
     }
 
     // Append Coredump data. This allow us to not have to talk to journald again on the drkonqi side.
     QSettings metadata(Metadata::metadataPath(dump.pid), QSettings::IniFormat);
     metadata.beginGroup(QStringLiteral("Journal"));
     for (auto it = dump.m_rawData.cbegin(); it != dump.m_rawData.cend(); ++it) {
         metadata.setValue(QString::fromUtf8(it.key()), it.value());
     }
     metadata.endGroup();
     metadata.sync();
 
     setenv("DRKONQI_BACKEND", "COREDUMPD", 1);
     setenv("DRKONQI_METADATA_FILE", qPrintable(metadataPath), 1);
 
     deleteFile.dismiss(); // let drkonqi handle cleanup if we get here
 
     // We must start drkonqi in a new slice. This launcher will want to terminate quickly and we enforce that
     // through maximum run time in the unit configuration. If drkonqi wasn't in a new slice it'd get killed with us.
     QProcess::execute(drkonqiExe(), arguments);
 
     return true; // always considered handled, even if drkonqi crashes or something
 }
 
 class DrKonqiTruck : public DumpTruckInterface
 {
 public:
     DrKonqiTruck() = default;
     ~DrKonqiTruck() override = default;
 
     bool handle(const Coredump &dump) override
     {
         if (!QFile::exists(dump.filename)) {
             QFile::remove(Metadata::resolveMetadataPath(dump.pid)); // without trace we'll never run drkonqi as it can't file a bug anyway
             return false;
         }
 
         return tryDrkonqi(dump);
     }
 
 private:
     Q_DISABLE_COPY_MOVE(DrKonqiTruck)
 };
 
 static void onNewDump(const Coredump &dump)
 {
     static DrKonqiTruck drkonqi;
     if (drkonqi.handle(dump)) {
         return;
     }
 
     if (qEnvironmentVariableIntValue("KDE_COREDUMP_NOTIFY") >= 1) {
         // Developers need to explicitly opt into the notifications. They
         // have no l10n and are also uniquely useless to users.
         static QPluginLoader loader(QStringLiteral("drkonqi/KDECoredumpNotifierTruck"));
         if (!loader.load()) {
             qWarning() << "failed to load" << loader.fileName() << loader.errorString();
             return;
         }
         auto notifier = qobject_cast<DumpTruckInterface *>(loader.instance());
         Q_ASSERT(notifier);
         if (notifier->handle(dump)) {
             return;
         }
     }
 
     qWarning() << "Nothing handled the dump :O";
 }
 
 int main(int argc, char **argv)
 {
     QCoreApplication app(argc, argv);
     app.setApplicationName(QStringLiteral("drkonqi-coredump-launcher"));
     app.setOrganizationDomain(QStringLiteral("kde.org"));
 
     if (sd_listen_fds(false) != 1) {
         qFatal("Not exactly one fd passed by systemd. Quel malheur!");
         return 1;
     }
 
     // Reading is very awkward and I'm not even sure why.
     // It seems like QLocalSocket doesn't manage to model stream sockets properly or at least not SOCK_SEQPACKET.
     // The socket on our end never notices that the remote has closed and even terminated already.
     //
     // Since we don't really need to do anything fancy we'll simply poll on our own instead of relying on QLS.
 
     QByteArray json;
     QByteArray segment;
     segment.resize(Socket::DatagramSize);
     while (true) {
         struct pollfd poll {
         };
         poll.fd = SD_LISTEN_FDS_START;
         poll.events = POLLIN;
         struct timespec time {
         };
         time.tv_nsec = (2500ns).count();
         ppoll(&poll, 1, &time, nullptr);
 
         if (poll.revents & POLLERR) {
             qFatal("Socket had an error");
             break;
         }
 
         if (poll.revents & POLLNVAL) {
             qFatal("Socket was invalid");
             break;
         }
 
         if (poll.revents & POLLIN) {
             const size_t size = read(poll.fd, segment.data(), segment.size());
             if (size == 0 && poll.revents & POLLHUP) {
                 break; // zero read + POLLHUP = EOS says the manpage
             }
             json.append(segment.data(), size);
         }
     }
     close(SD_LISTEN_FDS_START);
 
     QJsonParseError error{};
     const QJsonDocument document = QJsonDocument::fromJson(json, &error);
     if (error.error != QJsonParseError::NoError) {
         qWarning() << "json parse error" << error.errorString();
         return 1;
     }
 
     // Unset a slew of systemd variables.
     unsetenv("JOURNAL_STREAM");
     unsetenv("INVOCATION_ID");
     unsetenv("LISTEN_FDNAMES");
     unsetenv("LISTEN_FDS");
     unsetenv("LISTEN_PID");
     unsetenv("MANAGERPID");
 
     onNewDump(Coredump(document));
 
     return 0;
 }