trkgdbadapter.cpp

/**************************************************************************
**
** This file is part of Qt Creator
**
** Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).
**
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** Commercial Usage
**
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
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#include "trkgdbadapter.h"

#include "launcher.h"
#include "trkoptions.h"
#include "trkoptionspage.h"
#include "s60debuggerbluetoothstarter.h"
#include "bluetoothlistener_gui.h"

#include "registerhandler.h"
#include "debuggeractions.h"
#include "debuggerstringutils.h"
#ifndef STANDALONE_RUNNER
#include "gdbengine.h"
#endif

#include <utils/qtcassert.h>

#include <QtCore/QTimer>
#include <QtCore/QDir>

#ifdef Q_OS_WIN
#  include <windows.h>
#else
#  include <sys/types.h>
#  include <unistd.h>
#endif

#define CB(callback) \
    static_cast<GdbEngine::AdapterCallback>(&TrkGdbAdapter::callback), \
    STRINGIFY(callback)

#define TrkCB(s) TrkCallback(this, &TrkGdbAdapter::s)

//#define DEBUG_MEMORY  1
#if DEBUG_MEMORY
#   define MEMORY_DEBUG(s) qDebug() << s
#else
#   define MEMORY_DEBUG(s)
#endif
#define MEMORY_DEBUGX(s) qDebug() << s

using namespace trk;

namespace Debugger {
namespace Internal {

enum { KnownRegisters = RegisterPSGdb + 1};

static inline void appendByte(QByteArray *ba, trk::byte b) { ba->append(b); }

static const char *registerNames[KnownRegisters] =
{
    "A1", "A2", "A3", "A4",
    0, 0, 0, 0,
    0, 0, 0, "AP",
    "IP", "SP", "LR", "PC",
    "PSTrk", 0, 0, 0,
    0, 0, 0, 0,
    0, "PSGdb"
};

static QByteArray dumpRegister(uint n, uint value)
{
    QByteArray ba;
    ba += ' ';
    if (n < KnownRegisters && registerNames[n]) {
        ba += registerNames[n];
    } else {
        ba += '#';
        ba += QByteArray::number(n);
    }
    ba += '=';
    ba += hexxNumber(value);
    return ba;
}

static void appendRegister(QByteArray *ba, uint regno, uint value)
{
    ba->append(hexNumber(regno, 2));
    ba->append(':');
    ba->append(hexNumber(swapEndian(value), 8));
    ba->append(';');
}

QDebug operator<<(QDebug d, MemoryRange range)
{
    return d << QString("[%1,%2] (size %3) ")
        .arg(range.from, 0, 16).arg(range.to, 0, 16).arg(range.size());
}

///////////////////////////////////////////////////////////////////////////
//
// MemoryRange
//
///////////////////////////////////////////////////////////////////////////

MemoryRange::MemoryRange(uint f, uint t)
    : from(f), to(t)
{
    QTC_ASSERT(f <= t, qDebug() << "F: " << f << " T: " << t);
}

bool MemoryRange::intersects(const MemoryRange &other) const
{
    Q_UNUSED(other);
    QTC_ASSERT(false, /**/);
    return false; // FIXME
}

void MemoryRange::operator-=(const MemoryRange &other)
{
    if (from == 0 && to == 0)
        return;
    MEMORY_DEBUG("      SUB: "  << *this << " - " << other);
    if (other.from <= from && to <= other.to) {
        from = to = 0;
        return;
    }
    if (other.from <= from && other.to <= to) {
        from = qMax(from, other.to);
        return;
    }
    if (from <= other.from && to <= other.to) {
        to = qMin(other.from, to);
        return;
    }
    // This would split the range.
    QTC_ASSERT(false, qDebug() << "Memory::operator-() not handled for: "
        << *this << " - " << other);
}

///////////////////////////////////////////////////////////////////////////
//
// Snapshot
//
///////////////////////////////////////////////////////////////////////////

void Snapshot::reset()
{
    memory.clear();
    for (int i = 0; i < RegisterCount; ++i)
        registers[i] = 0;
    registerValid = false;
    wantedMemory = MemoryRange();
    lineFromAddress = 0;
    lineToAddress = 0;
}

void Snapshot::insertMemory(const MemoryRange &range, const QByteArray &ba)
{
    QTC_ASSERT(range.size() == uint(ba.size()),
        qDebug() << "RANGE: " << range << " BA SIZE: " << ba.size(); return);

    MEMORY_DEBUG("INSERT: " << range);
    // Try to combine with existing chunk.
    Snapshot::Memory::iterator it = memory.begin();
    Snapshot::Memory::iterator et = memory.end();
    for ( ; it != et; ++it) {
        if (range.from == it.key().to) {
            MEMORY_DEBUG("COMBINING " << it.key() << " AND " << range);
            QByteArray data = *it;
            data.append(ba);
            const MemoryRange res(it.key().from, range.to);
            memory.remove(it.key());
            MEMORY_DEBUG(" TO(1)  " << res);
            insertMemory(res, data);
            return;
        }
        if (it.key().from == range.to) {
            MEMORY_DEBUG("COMBINING " << range << " AND " << it.key());
            QByteArray data = ba;
            data.append(*it);
            const MemoryRange res(range.from, it.key().to);
            memory.remove(it.key());
            MEMORY_DEBUG(" TO(2)  " << res);
            insertMemory(res, data);
            return;
        }
    }

    // Not combinable, add chunk.
    memory.insert(range, ba);
}

///////////////////////////////////////////////////////////////////////////
//
// TrkGdbAdapter
//
///////////////////////////////////////////////////////////////////////////

TrkGdbAdapter::TrkGdbAdapter(GdbEngine *engine, const TrkOptionsPtr &options) :
    AbstractGdbAdapter(engine),
    m_options(options),
    m_overrideTrkDeviceType(-1),
    m_running(false),
    m_trkDevice(new trk::TrkDevice),
    m_gdbAckMode(true),
    m_verbose(0)
{
    m_bufferedMemoryRead = true;
    // Disable buffering if gdb's dcache is used.
    m_bufferedMemoryRead = false;

    m_gdbServer = 0;
    m_gdbConnection = 0;
    m_snapshot.reset();
#ifdef Q_OS_WIN
    const DWORD portOffset = GetCurrentProcessId() % 100;
#else
    const uid_t portOffset = getuid();
#endif
    m_gdbServerName = _("127.0.0.1:%1").arg(2222 + portOffset);

    connect(m_trkDevice.data(), SIGNAL(messageReceived(trk::TrkResult)),
        this, SLOT(handleTrkResult(trk::TrkResult)));
    connect(m_trkDevice.data(), SIGNAL(error(QString)),
        this, SLOT(handleTrkError(QString)));

    setVerbose(theDebuggerBoolSetting(VerboseLog));
    m_trkDevice->setSerialFrame(effectiveTrkDeviceType() != TrkOptions::BlueTooth);

    connect(m_trkDevice.data(), SIGNAL(logMessage(QString)),
        this, SLOT(trkLogMessage(QString)));
    connect(theDebuggerAction(VerboseLog), SIGNAL(valueChanged(QVariant)),
        this, SLOT(setVerbose(QVariant)));
}

TrkGdbAdapter::~TrkGdbAdapter()
{
    cleanup();
    logMessage("Shutting down.\n");
}

void TrkGdbAdapter::setVerbose(const QVariant &value)
{
    setVerbose(value.toInt());
}

void TrkGdbAdapter::setVerbose(int verbose)
{
    m_verbose = verbose;
    m_trkDevice->setVerbose(m_verbose);
}

QString TrkGdbAdapter::effectiveTrkDevice() const
{
    if (!m_overrideTrkDevice.isEmpty())
        return m_overrideTrkDevice;
    if (m_options->mode == TrkOptions::BlueTooth)
        return m_options->blueToothDevice;
    return m_options->serialPort;
}

int TrkGdbAdapter::effectiveTrkDeviceType() const
{
    if (m_overrideTrkDeviceType >= 0)
        return m_overrideTrkDeviceType;
    return m_options->mode;
}

void TrkGdbAdapter::trkLogMessage(const QString &msg)
{
    logMessage("TRK " + msg);
}

void TrkGdbAdapter::setGdbServerName(const QString &name)
{
    m_gdbServerName = name;
}

QString TrkGdbAdapter::gdbServerIP() const
{
    int pos = m_gdbServerName.indexOf(':');
    if (pos == -1)
        return m_gdbServerName;
    return m_gdbServerName.left(pos);
}

uint TrkGdbAdapter::gdbServerPort() const
{
    int pos = m_gdbServerName.indexOf(':');
    if (pos == -1)
        return 0;
    return m_gdbServerName.mid(pos + 1).toUInt();
}

QByteArray TrkGdbAdapter::trkContinueMessage()
{
    QByteArray ba;
    appendInt(&ba, m_session.pid);
    appendInt(&ba, m_session.tid);
    return ba;
}

QByteArray TrkGdbAdapter::trkReadRegistersMessage()
{
    QByteArray ba;
    appendByte(&ba, 0); // Register set, only 0 supported
    appendShort(&ba, 0);
    appendShort(&ba, RegisterCount - 1); // last register
    appendInt(&ba, m_session.pid);
    appendInt(&ba, m_session.tid);
    return ba;
}

   QByteArray TrkGdbAdapter::trkWriteRegisterMessage(trk::byte reg, uint value)
{
    QByteArray ba;
    appendByte(&ba, 0); // ?
    appendShort(&ba, reg);
    appendShort(&ba, reg);
    appendInt(&ba, m_session.pid);
    appendInt(&ba, m_session.tid);
    appendInt(&ba, value);
    return ba;
}

QByteArray TrkGdbAdapter::trkReadMemoryMessage(uint from, uint len)
{
    QByteArray ba;
    ba.reserve(11);
    appendByte(&ba, 0x08); // Options, FIXME: why?
    appendShort(&ba, len);
    appendInt(&ba, from);
    appendInt(&ba, m_session.pid);
    appendInt(&ba, m_session.tid);
    return ba;
}

QByteArray TrkGdbAdapter::trkReadMemoryMessage(const MemoryRange &range)
{
    return trkReadMemoryMessage(range.from, range.size());
}

QByteArray TrkGdbAdapter::trkWriteMemoryMessage(uint addr, const QByteArray &data)
{
    QByteArray ba;
    ba.reserve(11 + data.size());
    appendByte(&ba, 0x08); // Options, FIXME: why?
    appendShort(&ba, data.size());
    appendInt(&ba, addr);
    appendInt(&ba, m_session.pid);
    appendInt(&ba, m_session.tid);
    ba.append(data);
    return ba;
}

QByteArray TrkGdbAdapter::trkStepRangeMessage(trk::byte option)
{
    QByteArray ba;
    ba.reserve(17);
    appendByte(&ba, option);
    //qDebug() << "STEP ON " << hexxNumber(m_snapshot.registers[RegisterPC]);
    uint from = m_snapshot.lineFromAddress;
    uint to = m_snapshot.lineToAddress;
    uint pc = m_snapshot.registers[RegisterPC];
    if (from <= pc && pc <= to) {
        to = qMax(to - 4, from);
        debugMessage("STEP IN " + hexxNumber(from) + " " + hexxNumber(to)
            + " INSTEAD OF " + hexxNumber(pc));
    } else {
        from = pc;
        to = pc;
    }
    appendInt(&ba, from); // Start address
    appendInt(&ba, to); // End address
    appendInt(&ba, m_session.pid);
    appendInt(&ba, m_session.tid);
    return ba;
}

QByteArray TrkGdbAdapter::trkDeleteProcessMessage()
{
    QByteArray ba;
    ba.reserve(6);
    appendByte(&ba, 0); // ?
    appendByte(&ba, 0); // Sub-command: Delete Process
    appendInt(&ba, m_session.pid);
    return ba;
}

QByteArray TrkGdbAdapter::trkInterruptMessage()
{
    QByteArray ba;
    ba.reserve(9);
    // Stop the thread (2) or the process (1) or the whole system (0).
    // We choose 2, as 1 does not seem to work.
    appendByte(&ba, 2);
    appendInt(&ba, m_session.pid);
    appendInt(&ba, m_session.tid); // threadID: 4 bytes Variable number of bytes.
    return ba;
}

void TrkGdbAdapter::emitDelayedInferiorStartFailed(const QString &msg)
{
    m_adapterFailMessage = msg;
    QTimer::singleShot(0, this, SLOT(slotEmitDelayedInferiorStartFailed()));
}

void TrkGdbAdapter::slotEmitDelayedInferiorStartFailed()
{
    emit inferiorStartFailed(m_adapterFailMessage);
}


void TrkGdbAdapter::logMessage(const QString &msg)
{
    if (m_verbose)
        debugMessage("TRK LOG: " + msg);
}

//
// Gdb
//
void TrkGdbAdapter::handleGdbConnection()
{
    logMessage("HANDLING GDB CONNECTION");
    QTC_ASSERT(m_gdbConnection == 0, /**/);
    m_gdbConnection = m_gdbServer->nextPendingConnection();
    QTC_ASSERT(m_gdbConnection, return);
    connect(m_gdbConnection, SIGNAL(disconnected()),
            m_gdbConnection, SLOT(deleteLater()));
    connect(m_gdbConnection, SIGNAL(readyRead()),
            this, SLOT(readGdbServerCommand()));
}

static inline QString msgGdbPacket(const QString &p)
{
    return QLatin1String("gdb:                              ") + p;
}

void TrkGdbAdapter::readGdbServerCommand()
{
    QTC_ASSERT(m_gdbConnection, return);
    QByteArray packet = m_gdbConnection->readAll();
    m_gdbReadBuffer.append(packet);

    logMessage("gdb: -> " + QString::fromAscii(packet));
    if (packet != m_gdbReadBuffer)
        logMessage("buffer: " + m_gdbReadBuffer);

    QByteArray &ba = m_gdbReadBuffer;
    while (ba.size()) {
        char code = ba.at(0);
        ba = ba.mid(1);

        if (code == '+') {
            //logMessage("ACK");
            continue;
        }

        if (code == '-') {
            logMessage("NAK: Retransmission requested");
            // This seems too harsh.
            //emit adapterCrashed("Communication problem encountered.");
            continue;
        }

        if (code == char(0x03)) {
            logMessage("INTERRUPT RECEIVED");
            interruptInferior();
            continue;
        }

        if (code != '$') {
            logMessage("Broken package (2) " + quoteUnprintableLatin1(ba)
                + hexNumber(code));
            continue;
        }

        int pos = ba.indexOf('#');
        if (pos == -1) {
            logMessage("Invalid checksum format in "
                + quoteUnprintableLatin1(ba));
            continue;
        }

        bool ok = false;
        uint checkSum = ba.mid(pos + 1, 2).toUInt(&ok, 16);
        if (!ok) {
            logMessage("Invalid checksum format 2 in "
                + quoteUnprintableLatin1(ba));
            return;
        }

        //logMessage(QString("Packet checksum: %1").arg(checkSum));
        trk::byte sum = 0;
        for (int i = 0; i < pos; ++i)
            sum += ba.at(i);

        if (sum != checkSum) {
            logMessage(QString("ERROR: Packet checksum wrong: %1 %2 in "
                + quoteUnprintableLatin1(ba)).arg(checkSum).arg(sum));
        }

        QByteArray cmd = ba.left(pos);
        ba.remove(0, pos + 3);
        handleGdbServerCommand(cmd);
    }
}

bool TrkGdbAdapter::sendGdbServerPacket(const QByteArray &packet, bool doFlush)
{
    if (!m_gdbConnection) {
        logMessage(_("Cannot write to gdb: No connection (%1)")
            .arg(_(packet)));
        return false;
    }
    if (m_gdbConnection->state() != QAbstractSocket::ConnectedState) {
        logMessage(_("Cannot write to gdb: Not connected (%1)")
            .arg(_(packet)));
        return false;
    }
    if (m_gdbConnection->write(packet) == -1) {
        logMessage(_("Cannot write to gdb: %1 (%2)")
            .arg(m_gdbConnection->errorString()).arg(_(packet)));
        return false;
    }
    if (doFlush)
        m_gdbConnection->flush();
    return true;
}

void TrkGdbAdapter::sendGdbServerAck()
{
    if (!m_gdbAckMode)
        return;
    logMessage("gdb: <- +");
    sendGdbServerPacket(QByteArray(1, '+'), false);
}

void TrkGdbAdapter::sendGdbServerMessage(const QByteArray &msg, const QByteArray &logNote)
{
    trk::byte sum = 0;
    for (int i = 0; i != msg.size(); ++i)
        sum += msg.at(i);

    char checkSum[30];
    qsnprintf(checkSum, sizeof(checkSum) - 1, "%02x ", sum);

    //logMessage(QString("Packet checksum: %1").arg(sum));

    QByteArray packet;
    packet.append('$');
    packet.append(msg);
    packet.append('#');
    packet.append(checkSum);
    int pad = qMax(0, 24 - packet.size());
    logMessage("gdb: <- " + packet + QByteArray(pad, ' ') + logNote);
    sendGdbServerPacket(packet, true);
}

void TrkGdbAdapter::sendGdbServerMessageAfterTrkResponse(const QByteArray &msg,
    const QByteArray &logNote)
{
    QByteArray ba = msg + char(1) + logNote;
    sendTrkMessage(TRK_WRITE_QUEUE_NOOP_CODE, TrkCB(reportToGdb), "", ba); // Answer gdb
}

void TrkGdbAdapter::reportToGdb(const TrkResult &result)
{
    QByteArray message = result.cookie.toByteArray();
    QByteArray note;
    int pos = message.lastIndexOf(char(1)); // HACK
    if (pos != -1) {
        note = message.mid(pos + 1);
        message = message.left(pos);
    }
    message.replace("@CODESEG@", hexNumber(m_session.codeseg));
    message.replace("@DATASEG@", hexNumber(m_session.dataseg));
    message.replace("@PID@", hexNumber(m_session.pid));
    message.replace("@TID@", hexNumber(m_session.tid));
    sendGdbServerMessage(message, note);
}

QByteArray TrkGdbAdapter::trkBreakpointMessage(uint addr, uint len, bool armMode)
{
    QByteArray ba;
    appendByte(&ba, 0x82);  // unused option
    appendByte(&ba, armMode /*bp.mode == ArmMode*/ ? 0x00 : 0x01);
    appendInt(&ba, addr);
    appendInt(&ba, len);
    appendInt(&ba, 0x00000001);
    appendInt(&ba, m_session.pid);
    appendInt(&ba, 0xFFFFFFFF);
    return ba;
}

void TrkGdbAdapter::handleGdbServerCommand(const QByteArray &cmd)
{
    // http://sourceware.org/gdb/current/onlinedocs/gdb_34.html
    if (0) {}

    else if (cmd == "!") {
        sendGdbServerAck();
        //sendGdbServerMessage("", "extended mode not enabled");
        sendGdbServerMessage("OK", "extended mode enabled");
    }

    else if (cmd.startsWith('?')) {
        logMessage(msgGdbPacket(QLatin1String("Query halted")));
        // Indicate the reason the target halted.
        // The reply is the same as for step and continue.
        sendGdbServerAck();
        // The command below will trigger fetching a stack trace while
        // the process does not seem to be fully functional. Most notably
        // the PC points to a 0x9..., which is not in "our" range
        //sendGdbServerMessage("T05library:r;", "target halted (library load)");
        //sendGdbServerMessage("S05", "target halted (trap)");
        sendGdbServerMessage("S00", "target halted (trap)");
        //sendGdbServerMessage("O" + QByteArray("Starting...").toHex());
    }

    else if (cmd == "c") {
        logMessage(msgGdbPacket(QLatin1String("Continue")));
        sendGdbServerAck();
        QByteArray ba;
        appendByte(&ba, 0); // options
        appendInt(&ba, 0); // start address
        appendInt(&ba, 0); // end address
        appendInt(&ba, m_session.pid);
        appendInt(&ba, m_session.tid);
        sendTrkMessage(0x18, TrkCallback(), ba);
    }

    else if (cmd.startsWith('C')) {
        logMessage(msgGdbPacket(QLatin1String("Continue with signal")));
        // C sig[;addr] Continue with signal sig (hex signal number)
        //Reply: See section D.3 Stop Reply Packets, for the reply specifications.
        sendGdbServerAck();
        bool ok = false;
        uint signalNumber = cmd.mid(1).toUInt(&ok, 16);
        QByteArray ba;
        appendInt(&ba, m_session.pid);
        appendInt(&ba, m_session.tid);
        sendTrkMessage(0x18, TrkCB(handleSignalContinue), ba, signalNumber);
    }

    else if (cmd.startsWith('D')) {
        sendGdbServerAck();
        sendGdbServerMessage("OK", "shutting down");
    }

    else if (cmd == "g") {
        // Read general registers.
        if (m_snapshot.registerValid) {
            //qDebug() << "Using cached register contents";
            logMessage(msgGdbPacket(QLatin1String("Read registers")));
            sendGdbServerAck();
            reportRegisters();
        } else {
            //qDebug() << "Fetching register contents";
            sendGdbServerAck();
            sendTrkMessage(0x12,
                TrkCB(handleAndReportReadRegisters),
                trkReadRegistersMessage());
        }
    }

    else if (cmd == "gg") {
        // Force re-reading general registers for debugging purpose.
        sendGdbServerAck();
        m_snapshot.registerValid = false;
        sendTrkMessage(0x12,
            TrkCB(handleAndReportReadRegisters),
            trkReadRegistersMessage());
    }

    else if (cmd.startsWith("sal")) {
        // Receive address range for current line for future use when stepping.
        sendGdbServerAck();
        int pos = cmd.indexOf(',');
        //qDebug() << "SAL: " << cmd << cmd.mid(3, pos - 3) << cmd.mid(pos + 1);
        m_snapshot.lineFromAddress = cmd.mid(3, pos - 3).toUInt(0, 16);
        m_snapshot.lineToAddress = cmd.mid(pos + 1).toUInt(0, 16);
        //qDebug() << "SAL: " << hexxNumber(m_snapshot.lineFromAddress)
        //    << hexxNumber(m_snapshot.lineToAddress);
        sendGdbServerMessage("", "Stepping range received");
    }

    else if (cmd.startsWith("Hc")) {
        logMessage(msgGdbPacket(QLatin1String("Set thread & continue")));
        // Set thread for subsequent operations (`m', `M', `g', `G', et.al.).
        // for step and continue operations
        //$Hc-1#09
        sendGdbServerAck();
        sendGdbServerMessage("OK", "Set current thread for step & continue");
    }

    else if (cmd.startsWith("Hg")) {
        logMessage(msgGdbPacket(QLatin1String("Set thread")));
        // Set thread for subsequent operations (`m', `M', `g', `G', et.al.).
        // for 'other operations.  0 - any thread
        //$Hg0#df
        sendGdbServerAck();
        m_session.currentThread = cmd.mid(2).toUInt(0, 16);
        sendGdbServerMessage("OK", "Set current thread "
            + QByteArray::number(m_session.currentThread));
    }

    else if (cmd == "k" || cmd.startsWith("vKill")) {
        // Kill inferior process
        logMessage(msgGdbPacket(QLatin1String("kill")));
        sendTrkMessage(0x41, TrkCB(handleDeleteProcess),
            trkDeleteProcessMessage(), "Delete process");
    }

    else if (cmd.startsWith('m')) {
        logMessage(msgGdbPacket(QLatin1String("Read memory")));
        // m addr,length
        sendGdbServerAck();
        uint addr = 0, len = 0;
        do {
            const int pos = cmd.indexOf(',');
            if (pos == -1)
                break;
            bool ok;
            addr = cmd.mid(1, pos - 1).toUInt(&ok, 16);
            if (!ok)
                break;
            len = cmd.mid(pos + 1).toUInt(&ok, 16);
            if (!ok)
                break;
        } while (false);
        if (len) {
            readMemory(addr, len, m_bufferedMemoryRead);
        } else {
            sendGdbServerMessage("E20", "Error " + cmd);
        }
    }

    else if (cmd.startsWith('p')) {
        logMessage(msgGdbPacket(QLatin1String("read register")));
        // 0xf == current instruction pointer?
        //sendGdbServerMessage("0000", "current IP");
        sendGdbServerAck();
        bool ok = false;
        const uint registerNumber = cmd.mid(1).toUInt(&ok, 16);
        if (m_snapshot.registerValid) {
            QByteArray logMsg = "Read Register";
            if (registerNumber == RegisterPSGdb) {
                QByteArray ba;
                appendInt(&ba, m_snapshot.registers[RegisterPSTrk], LittleEndian);
                logMsg += dumpRegister(registerNumber, m_snapshot.registers[RegisterPSTrk]);
                sendGdbServerMessage(ba.toHex(), logMsg);
            } else if (registerNumber < 16) {
                QByteArray ba;
                appendInt(&ba, m_snapshot.registers[registerNumber], LittleEndian);
                logMsg += dumpRegister(registerNumber, m_snapshot.registers[registerNumber]);
                sendGdbServerMessage(ba.toHex(), logMsg);
            } else {
                sendGdbServerMessage("0000", "read single unknown register #"
                    + QByteArray::number(registerNumber));
                //sendGdbServerMessage("E01", "read single unknown register");
            }
        } else {
            //qDebug() << "Fetching single register";
            sendTrkMessage(0x12,
                TrkCB(handleAndReportReadRegister),
                trkReadRegistersMessage(), registerNumber);
        }
    }

    else if (cmd.startsWith('P')) {
        logMessage(msgGdbPacket(QLatin1String("write register")));
        // $Pe=70f96678#d3
        sendGdbServerAck();
        int pos = cmd.indexOf('=');
        QByteArray regName = cmd.mid(1, pos - 1);
        QByteArray valueName = cmd.mid(pos + 1);
        bool ok = false;
        const uint registerNumber = regName.toUInt(&ok, 16);
        const uint value = swapEndian(valueName.toUInt(&ok, 16));
        // FIXME: Assume all goes well.
        m_snapshot.registers[registerNumber] = value;
        QByteArray ba = trkWriteRegisterMessage(registerNumber, value);
        sendTrkMessage(0x13, TrkCB(handleWriteRegister), ba, "Write register");
        // Note that App TRK refuses to write registers 13 and 14
    }

    else if (cmd == "qAttached") {
        //$qAttached#8f
        // 1: attached to an existing process
        // 0: created a new process
        sendGdbServerAck();
        sendGdbServerMessage(QByteArray(1, '0'), "new process created");
        //sendGdbServerMessage('1', "attached to existing process");
        //sendGdbServerMessage("E01", "new process created");
    }

    else if (cmd.startsWith("qC")) {
        logMessage(msgGdbPacket(QLatin1String("query thread id")));
        // Return the current thread ID
        //$qC#b4
        sendGdbServerAck();
        sendGdbServerMessageAfterTrkResponse("QC@TID@");
    }

    else if (cmd.startsWith("qSupported")) {
        //$qSupported#37
        //$qSupported:multiprocess+#c6
        //logMessage("Handling 'qSupported'");
        sendGdbServerAck();
        sendGdbServerMessage(
            "PacketSize=7cf;"
            "QPassSignals+;"
            "QStartNoAckMode+;"
            "qXfer:libraries:read+;"
            //"qXfer:auxv:read+;"
            "qXfer:features:read+");
    }

    else if (cmd.startsWith("qThreadExtraInfo")) {
        // $qThreadExtraInfo,1f9#55
        sendGdbServerAck();
        sendGdbServerMessage(QByteArray("Nothing special").toHex());
    }

    else if (cmd == "qfDllInfo") {
        // That's the _first_ query package.
        // Happens with  gdb 6.4.50.20060226-cvs / CodeSourcery.
        // Never made it into FSF gdb that got qXfer:libraries:read instead.
        // http://sourceware.org/ml/gdb/2007-05/msg00038.html
        // Name=hexname,TextSeg=textaddr[,DataSeg=dataaddr]
        sendGdbServerAck();
        if (!m_session.libraries.isEmpty()) {
            QByteArray response(1, 'm');
            // FIXME: Limit packet length by using qsDllInfo packages?
            for (int i = 0; i != m_session.libraries.size(); ++i) {
                if (i)
                    response += ';';
                const Library &lib = m_session.libraries.at(i);
                response += "Name=" + lib.name.toHex()
                            + ",TextSeg=" + hexNumber(lib.codeseg)
                            + ",DataSeg=" + hexNumber(lib.dataseg);
            }
            sendGdbServerMessage(response, "library information transferred");
        } else {
            sendGdbServerMessage(QByteArray(1, 'l'), "library information transfer finished");
        }
    }

    else if (cmd == "qsDllInfo") {
        // That's a following query package
        sendGdbServerAck();
        sendGdbServerMessage(QByteArray(1, 'l'), "library information transfer finished");
    }

    else if (cmd == "qPacketInfo") {
        // happens with  gdb 6.4.50.20060226-cvs / CodeSourcery
        // deprecated by qSupported?
        sendGdbServerAck();
        sendGdbServerMessage("", "FIXME: nothing?");
    }

    else if (cmd == "qOffsets") {
        sendGdbServerAck();
        sendGdbServerMessageAfterTrkResponse("TextSeg=@CODESEG@;DataSeg=@DATASEG@");
    }

    else if (cmd == "qSymbol::") {
        if (m_verbose)
            logMessage(msgGdbPacket(QLatin1String("notify can handle symbol lookup")));
        // Notify the target that GDB is prepared to serve symbol lookup requests.
        sendGdbServerAck();
        if (1)
            sendGdbServerMessage("OK", "no further symbols needed");
        else
            sendGdbServerMessage("qSymbol:" + QByteArray("_Z7E32Mainv").toHex(),
                "ask for more");
    }

    else if (cmd.startsWith("qXfer:features:read:target.xml:")) {
        //  $qXfer:features:read:target.xml:0,7ca#46...Ack
        sendGdbServerAck();
        //sendGdbServerMessage("l<target><architecture>symbianelf</architecture></target>");
        sendGdbServerMessage("l<target><architecture>arm</architecture></target>");
        //sendGdbServerMessage("l<target><architecture>arm-none-symbianelf</architecture></target>");
    }

    else if (cmd == "qfThreadInfo") {
        // That's the _first_ query package.
        sendGdbServerAck();
        if (!m_session.threads.isEmpty()) {
            QByteArray response(1, 'm');
            // FIXME: Limit packet length by using qsThreadInfo packages?
            qDebug()  << "CURRENT THREAD: " << m_session.tid;
            response += hexNumber(m_session.tid);
            sendGdbServerMessage(response, "thread information transferred");
        } else {
            sendGdbServerMessage(QByteArray(1, 'l'), "thread information transfer finished");
        }
    }

    else if (cmd == "qsThreadInfo") {
        // That's a following query package
        sendGdbServerAck();
        sendGdbServerMessage(QByteArray(1, 'l'), "thread information transfer finished");
    }

    else if (cmd.startsWith("qXfer:libraries:read")) {
        //qDebug() << "COMMAND: " << cmd;
        sendGdbServerAck();
        QByteArray response = "l<library-list>";
        for (int i = 0; i != m_session.libraries.size(); ++i) {
            const Library &lib = m_session.libraries.at(i);
            response += "<library name=\"" + lib.name + "\">";
            //response += "<segment address=\"0x" + hexNumber(lib.codeseg) + "\"/>";
            response += "<section address=\"0x" + hexNumber(lib.codeseg) + "\"/>";
            response += "<section address=\"0x" + hexNumber(lib.dataseg) + "\"/>";
            response += "<section address=\"0x" + hexNumber(lib.dataseg) + "\"/>";
            response += "</library>";
        }
        response += "</library-list>";
        sendGdbServerMessage(response, "library information transferred");
    }

    else if (cmd == "QStartNoAckMode") {
        //$qSupported#37
        logMessage("Handling 'QStartNoAckMode'");
        sendGdbServerAck();
        sendGdbServerMessage("OK", "ack no-ack mode");
        m_gdbAckMode = false;
    }

    else if (cmd.startsWith("QPassSignals")) {
        // list of signals to pass directly to inferior
        // $QPassSignals:e;10;14;17;1a;1b;1c;21;24;25;4c;#8f
        // happens only if "QPassSignals+;" is qSupported
        sendGdbServerAck();
        // FIXME: use the parameters
        sendGdbServerMessage("OK", "passing signals accepted");
    }

    else if (cmd == "s" || cmd.startsWith("vCont;s")) {
        logMessage(msgGdbPacket(QLatin1String("Step range")));
        logMessage("  from " + hexxNumber(m_snapshot.registers[RegisterPC]));
        sendGdbServerAck();
        //m_snapshot.reset();
        m_running = true;
        QByteArray ba = trkStepRangeMessage(0x01);  // options "step into"
        sendTrkMessage(0x19, TrkCB(handleStepInto), ba, "Step range");
    }

    else if (cmd.startsWith('T')) {
        // FIXME: check whether thread is alive
        sendGdbServerAck();
        sendGdbServerMessage("OK"); // pretend all is well
        //sendGdbServerMessage("E nn");
    }

    else if (cmd == "vCont?") {
        // actions supported by the vCont packet
        sendGdbServerAck();
        //sendGdbServerMessage("OK"); // we don't support vCont.
        sendGdbServerMessage("vCont;c;C;s;S");
    }

    else if (cmd == "vCont;c") {
        // vCont[;action[:thread-id]]...'
        sendGdbServerAck();
        //m_snapshot.reset();
        m_running = true;
        sendTrkMessage(0x18, TrkCallback(), trkContinueMessage(), "CONTINUE");
    }

    else if (cmd.startsWith("Z0,") || cmd.startsWith("Z1,")) {
        // Insert breakpoint
        sendGdbServerAck();
        logMessage(msgGdbPacket(QLatin1String("Insert breakpoint")));
        // $Z0,786a4ccc,4#99