lldb/source/Plugins/Process/MacOSX-Kernel/CommunicationKDP.cpp

//===-- CommunicationKDP.cpp ------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//


#include "CommunicationKDP.h"

// C Includes
#include <errno.h>
#include <limits.h>
#include <string.h>

// C++ Includes

// Other libraries and framework includes
#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/State.h"
#include "lldb/Core/UUID.h"
#include "lldb/Host/FileSpec.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/TimeValue.h"
#include "lldb/Target/Process.h"

// Project includes
#include "ProcessKDPLog.h"

using namespace lldb;
using namespace lldb_private;

//----------------------------------------------------------------------
// CommunicationKDP constructor
//----------------------------------------------------------------------
CommunicationKDP::CommunicationKDP(const char *comm_name)
    : Communication(comm_name),
      m_addr_byte_size(4),
      m_byte_order(eByteOrderLittle),
      m_packet_timeout(5),
      m_sequence_mutex(),
      m_is_running(false),
      m_session_key(0u),
      m_request_sequence_id(0u),
      m_exception_sequence_id(0u),
      m_kdp_version_version(0u),
      m_kdp_version_feature(0u),
      m_kdp_hostinfo_cpu_mask(0u),
      m_kdp_hostinfo_cpu_type(0u),
      m_kdp_hostinfo_cpu_subtype(0u)
{
}

//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
CommunicationKDP::~CommunicationKDP()
{
    if (IsConnected())
    {
        Disconnect();
    }
}

bool
CommunicationKDP::SendRequestPacket (const PacketStreamType &request_packet)
{
    std::lock_guard<std::recursive_mutex> guard(m_sequence_mutex);
    return SendRequestPacketNoLock (request_packet);
}

#if 0
typedef struct {
	uint8_t     request;	// Either: CommandType | ePacketTypeRequest, or CommandType | ePacketTypeReply
	uint8_t     sequence;
	uint16_t    length;		// Length of entire packet including this header
	uint32_t	key;		// Session key
} kdp_hdr_t;
#endif

void
CommunicationKDP::MakeRequestPacketHeader (CommandType request_type,
                                           PacketStreamType &request_packet,
                                           uint16_t request_length)
{
    request_packet.Clear();
    request_packet.PutHex8 (request_type | ePacketTypeRequest); // Set the request type
    request_packet.PutHex8 (m_request_sequence_id++);           // Sequence number
    request_packet.PutHex16 (request_length);                   // Length of the packet including this header
    request_packet.PutHex32 (m_session_key);                    // Session key
}

bool
CommunicationKDP::SendRequestAndGetReply (const CommandType command,
                                          const PacketStreamType &request_packet,
                                          DataExtractor &reply_packet)
{
    if (IsRunning())
    {
        Log *log (ProcessKDPLog::GetLogIfAllCategoriesSet (KDP_LOG_PACKETS));
        if (log)
        {
            PacketStreamType log_strm;
            DumpPacket (log_strm, request_packet.GetData(), request_packet.GetSize());
            log->Printf("error: kdp running, not sending packet: %.*s", (uint32_t)log_strm.GetSize(), log_strm.GetData());
        }
        return false;
    }

    std::lock_guard<std::recursive_mutex> guard(m_sequence_mutex);
#ifdef LLDB_CONFIGURATION_DEBUG
    // NOTE: this only works for packets that are in native endian byte order
    assert (request_packet.GetSize() == *((uint16_t *)(request_packet.GetData() + 2)));
#endif
    lldb::offset_t offset = 1;
    const uint32_t num_retries = 3;
    for (uint32_t i=0; i<num_retries; ++i)
    {
        if (SendRequestPacketNoLock(request_packet))
        {
            const uint8_t request_sequence_id = (uint8_t)request_packet.GetData()[1];
            while (1)
            {
                if (WaitForPacketWithTimeoutMicroSecondsNoLock (reply_packet, GetPacketTimeoutInMicroSeconds ()))
                {
                    offset = 0;
                    const uint8_t reply_command = reply_packet.GetU8 (&offset);
                    const uint8_t reply_sequence_id = reply_packet.GetU8 (&offset);
                    if (request_sequence_id == reply_sequence_id)
                    {
                        // The sequent ID was correct, now verify we got the response we were looking for
                        if ((reply_command & eCommandTypeMask) == command)
                        {
                            // Success
                            if (command == KDP_RESUMECPUS)
                                m_is_running.SetValue(true, eBroadcastAlways);
                            return true;
                        }
                        else
                        {
                            // Failed to get the correct response, bail
                            reply_packet.Clear();
                            return false;
                        }
                    }
                    else if (reply_sequence_id > request_sequence_id)
                    {
                        // Sequence ID was greater than the sequence ID of the packet we sent, something
                        // is really wrong...
                        reply_packet.Clear();
                        return false;
                    }
                    else
                    {
                        // The reply sequence ID was less than our current packet's sequence ID
                        // so we should keep trying to get a response because this was a response
                        // for a previous packet that we must have retried.
                    }
                }
                else
                {
                    // Break and retry sending the packet as we didn't get a response due to timeout
                    break;
                }
            }
        }
    }
    reply_packet.Clear();
    return false;
}

bool
CommunicationKDP::SendRequestPacketNoLock (const PacketStreamType &request_packet)
{
    if (IsConnected())
    {
        const char *packet_data = request_packet.GetData();
        const size_t packet_size = request_packet.GetSize();

        Log *log (ProcessKDPLog::GetLogIfAllCategoriesSet (KDP_LOG_PACKETS));
        if (log)
        {
            PacketStreamType log_strm;            
            DumpPacket (log_strm, packet_data, packet_size);
            log->Printf("%.*s", (uint32_t)log_strm.GetSize(), log_strm.GetData());
        }
        ConnectionStatus status = eConnectionStatusSuccess;

        size_t bytes_written = Write (packet_data, 
                                      packet_size, 
                                      status, 
                                      NULL);

        if (bytes_written == packet_size)
            return true;
        
        if (log)
            log->Printf ("error: failed to send packet entire packet %" PRIu64 " of %" PRIu64 " bytes sent", (uint64_t)bytes_written, (uint64_t)packet_size);
    }
    return false;
}

bool
CommunicationKDP::GetSequenceMutex(std::unique_lock<std::recursive_mutex> &lock)
{
    return (lock = std::unique_lock<std::recursive_mutex>(m_sequence_mutex, std::try_to_lock)).owns_lock();
}


bool
CommunicationKDP::WaitForNotRunningPrivate (const TimeValue *timeout_ptr)
{
    return m_is_running.WaitForValueEqualTo (false, timeout_ptr, NULL);
}

size_t
CommunicationKDP::WaitForPacketWithTimeoutMicroSeconds (DataExtractor &packet, uint32_t timeout_usec)
{
    std::lock_guard<std::recursive_mutex> guard(m_sequence_mutex);
    return WaitForPacketWithTimeoutMicroSecondsNoLock (packet, timeout_usec);
}

size_t
CommunicationKDP::WaitForPacketWithTimeoutMicroSecondsNoLock (DataExtractor &packet, uint32_t timeout_usec)
{
    uint8_t buffer[8192];
    Error error;

    Log *log (ProcessKDPLog::GetLogIfAllCategoriesSet (KDP_LOG_PACKETS | KDP_LOG_VERBOSE));

    // Check for a packet from our cache first without trying any reading...
    if (CheckForPacket (NULL, 0, packet))
        return packet.GetByteSize();

    bool timed_out = false;
    while (IsConnected() && !timed_out)
    {
        lldb::ConnectionStatus status = eConnectionStatusNoConnection;
        size_t bytes_read = Read (buffer, sizeof(buffer), timeout_usec, status, &error);
        
        if (log)
            log->Printf ("%s: Read (buffer, (sizeof(buffer), timeout_usec = 0x%x, status = %s, error = %s) => bytes_read = %" PRIu64,
                         __PRETTY_FUNCTION__,
                         timeout_usec, 
                         Communication::ConnectionStatusAsCString (status),
                         error.AsCString(), 
                         (uint64_t)bytes_read);

        if (bytes_read > 0)
        {
            if (CheckForPacket (buffer, bytes_read, packet))
                return packet.GetByteSize();
        }
        else
        {
            switch (status)
            {
            case eConnectionStatusInterrupted:
            case eConnectionStatusTimedOut:
                timed_out = true;
                break;
            case eConnectionStatusSuccess:
                //printf ("status = success but error = %s\n", error.AsCString("<invalid>"));
                break;
                
            case eConnectionStatusEndOfFile:
            case eConnectionStatusNoConnection:
            case eConnectionStatusLostConnection:
            case eConnectionStatusError:
                Disconnect();
                break;
            }
        }
    }
    packet.Clear ();    
    return 0;
}

bool
CommunicationKDP::CheckForPacket (const uint8_t *src, size_t src_len, DataExtractor &packet)
{
    // Put the packet data into the buffer in a thread safe fashion
    std::lock_guard<std::recursive_mutex> guard(m_bytes_mutex);

    Log *log (ProcessKDPLog::GetLogIfAllCategoriesSet (KDP_LOG_PACKETS));

    if (src && src_len > 0)
    {
        if (log && log->GetVerbose())
        {
            PacketStreamType log_strm;
            DataExtractor::DumpHexBytes (&log_strm, src, src_len, UINT32_MAX, LLDB_INVALID_ADDRESS);
            log->Printf ("CommunicationKDP::%s adding %u bytes: %s",
                         __FUNCTION__, 
                         (uint32_t)src_len, 
                         log_strm.GetData());
        }
        m_bytes.append ((const char *)src, src_len);
    }

    // Make sure we at least have enough bytes for a packet header
    const size_t bytes_available = m_bytes.size();
    if (bytes_available >= 8)
    {
        packet.SetData (&m_bytes[0], bytes_available, m_byte_order);
        lldb::offset_t offset = 0;
        uint8_t reply_command = packet.GetU8(&offset);
        switch (reply_command)
        {
        case ePacketTypeRequest | KDP_EXCEPTION:
        case ePacketTypeRequest | KDP_TERMINATION:
            // We got an exception request, so be sure to send an ACK
            {
                PacketStreamType request_ack_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
                // Set the reply but and make the ACK packet
                request_ack_packet.PutHex8 (reply_command | ePacketTypeReply);
                request_ack_packet.PutHex8 (packet.GetU8(&offset));
                request_ack_packet.PutHex16 (packet.GetU16(&offset));
                request_ack_packet.PutHex32 (packet.GetU32(&offset));
                m_is_running.SetValue(false, eBroadcastAlways);
                // Ack to the exception or termination
                SendRequestPacketNoLock (request_ack_packet);
            }
            // Fall through to case below to get packet contents
            LLVM_FALLTHROUGH;
        case ePacketTypeReply | KDP_CONNECT:
        case ePacketTypeReply | KDP_DISCONNECT:
        case ePacketTypeReply | KDP_HOSTINFO:
        case ePacketTypeReply | KDP_VERSION:
        case ePacketTypeReply | KDP_MAXBYTES:
        case ePacketTypeReply | KDP_READMEM:
        case ePacketTypeReply | KDP_WRITEMEM:
        case ePacketTypeReply | KDP_READREGS:
        case ePacketTypeReply | KDP_WRITEREGS:
        case ePacketTypeReply | KDP_LOAD:
        case ePacketTypeReply | KDP_IMAGEPATH:
        case ePacketTypeReply | KDP_SUSPEND:
        case ePacketTypeReply | KDP_RESUMECPUS:
        case ePacketTypeReply | KDP_BREAKPOINT_SET:
        case ePacketTypeReply | KDP_BREAKPOINT_REMOVE:
        case ePacketTypeReply | KDP_REGIONS:
        case ePacketTypeReply | KDP_REATTACH:
        case ePacketTypeReply | KDP_HOSTREBOOT:
        case ePacketTypeReply | KDP_READMEM64:
        case ePacketTypeReply | KDP_WRITEMEM64:
        case ePacketTypeReply | KDP_BREAKPOINT_SET64:
        case ePacketTypeReply | KDP_BREAKPOINT_REMOVE64:
        case ePacketTypeReply | KDP_KERNELVERSION:
        case ePacketTypeReply | KDP_READPHYSMEM64:
        case ePacketTypeReply | KDP_WRITEPHYSMEM64:
        case ePacketTypeReply | KDP_READIOPORT:
        case ePacketTypeReply | KDP_WRITEIOPORT:
        case ePacketTypeReply | KDP_READMSR64:
        case ePacketTypeReply | KDP_WRITEMSR64:
        case ePacketTypeReply | KDP_DUMPINFO:
            {
                offset = 2;
                const uint16_t length = packet.GetU16 (&offset);
                if (length <= bytes_available)
                {
                    // We have an entire packet ready, we need to copy the data
                    // bytes into a buffer that will be owned by the packet and
                    // erase the bytes from our communcation buffer "m_bytes"
                    packet.SetData (DataBufferSP (new DataBufferHeap (&m_bytes[0], length)));
                    m_bytes.erase (0, length);
                    
                    if (log)
                    {
                        PacketStreamType log_strm;
                        DumpPacket (log_strm, packet);
                        
                        log->Printf("%.*s", (uint32_t)log_strm.GetSize(), log_strm.GetData());
                    }
                    return true;
                }
            }
            break;

        default:
            // Unrecognized reply command byte, erase this byte and try to get back on track
            if (log)
                log->Printf ("CommunicationKDP::%s: tossing junk byte: 0x%2.2x", 
                             __FUNCTION__, 
                             (uint8_t)m_bytes[0]);
            m_bytes.erase(0, 1);
            break;
        }
    }
    packet.Clear();
    return false;
}


bool
CommunicationKDP::SendRequestConnect (uint16_t reply_port, 
                                      uint16_t exc_port, 
                                      const char *greeting)
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    if (greeting == NULL)
        greeting = "";

    const CommandType command = KDP_CONNECT;
    // Length is 82 uint16_t and the length of the greeting C string with the terminating NULL
    const uint32_t command_length = 8 + 2 + 2 + ::strlen(greeting) + 1;
    MakeRequestPacketHeader (command, request_packet, command_length);
    // Always send connect ports as little endian
    request_packet.SetByteOrder (eByteOrderLittle);
    request_packet.PutHex16 (htons(reply_port));
    request_packet.PutHex16 (htons(exc_port));
    request_packet.SetByteOrder (m_byte_order);
    request_packet.PutCString (greeting);
    DataExtractor reply_packet;
    return SendRequestAndGetReply (command, request_packet, reply_packet);
}

void
CommunicationKDP::ClearKDPSettings ()
{
    m_request_sequence_id = 0;
    m_kdp_version_version = 0;
    m_kdp_version_feature = 0;
    m_kdp_hostinfo_cpu_mask = 0;
    m_kdp_hostinfo_cpu_type = 0;
    m_kdp_hostinfo_cpu_subtype = 0;
}

bool
CommunicationKDP::SendRequestReattach (uint16_t reply_port)
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_REATTACH;
    // Length is 8 bytes for the header plus 2 bytes for the reply UDP port
    const uint32_t command_length = 8 + 2;
    MakeRequestPacketHeader (command, request_packet, command_length);
    // Always send connect ports as little endian
    request_packet.SetByteOrder (eByteOrderLittle);
    request_packet.PutHex16(htons(reply_port));
    request_packet.SetByteOrder (m_byte_order);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        // Reset the sequence ID to zero for reattach
        ClearKDPSettings ();
        lldb::offset_t offset = 4;
        m_session_key = reply_packet.GetU32 (&offset);
        return true;
    }
    return false;
}

uint32_t
CommunicationKDP::GetVersion ()
{
    if (!VersionIsValid())
        SendRequestVersion();
    return m_kdp_version_version;
}

uint32_t
CommunicationKDP::GetFeatureFlags ()
{
    if (!VersionIsValid())
        SendRequestVersion();
    return m_kdp_version_feature;
}

bool
CommunicationKDP::SendRequestVersion ()
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_VERSION;
    const uint32_t command_length = 8;
    MakeRequestPacketHeader (command, request_packet, command_length);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        lldb::offset_t offset = 8;
        m_kdp_version_version = reply_packet.GetU32 (&offset);
        m_kdp_version_feature = reply_packet.GetU32 (&offset);
        return true;
    }
    return false;
}

#if 0 // Disable KDP_IMAGEPATH for now, it seems to hang the KDP connection...
const char *
CommunicationKDP::GetImagePath ()
{
    if (m_image_path.empty())
        SendRequestImagePath();
    return m_image_path.c_str();
}

bool
CommunicationKDP::SendRequestImagePath ()
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_IMAGEPATH;
    const uint32_t command_length = 8;
    MakeRequestPacketHeader (command, request_packet, command_length);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        const char *path = reply_packet.PeekCStr(8);
        if (path && path[0])
            m_kernel_version.assign (path);
        return true;
    }
    return false;
}
#endif

uint32_t
CommunicationKDP::GetCPUMask ()
{
    if (!HostInfoIsValid())
        SendRequestHostInfo();
    return m_kdp_hostinfo_cpu_mask;
}

uint32_t
CommunicationKDP::GetCPUType ()
{
    if (!HostInfoIsValid())
        SendRequestHostInfo();
    return m_kdp_hostinfo_cpu_type;
}

uint32_t
CommunicationKDP::GetCPUSubtype ()
{
    if (!HostInfoIsValid())
        SendRequestHostInfo();
    return m_kdp_hostinfo_cpu_subtype;
}

lldb_private::UUID
CommunicationKDP::GetUUID ()
{
    UUID uuid;
    if (GetKernelVersion() == NULL)
        return uuid;

    if (m_kernel_version.find("UUID=") == std::string::npos)
        return uuid;

    size_t p = m_kernel_version.find("UUID=") + strlen ("UUID=");
    std::string uuid_str = m_kernel_version.substr(p, 36);
    if (uuid_str.size() < 32)
        return uuid;

    if (uuid.SetFromCString (uuid_str.c_str()) == 0)
    {
        UUID invalid_uuid;
        return invalid_uuid;
    }

    return uuid;
}

bool
CommunicationKDP::RemoteIsEFI ()
{
    if (GetKernelVersion() == NULL)
        return false;
    if (strncmp (m_kernel_version.c_str(), "EFI", 3) == 0)
        return true;
    else
        return false;
}

bool
CommunicationKDP::RemoteIsDarwinKernel ()
{
    if (GetKernelVersion() == NULL)
        return false;
    if (m_kernel_version.find("Darwin Kernel") != std::string::npos)
        return true;
    else
        return false;
}

lldb::addr_t
CommunicationKDP::GetLoadAddress ()
{
    if (GetKernelVersion() == NULL)
        return LLDB_INVALID_ADDRESS;

    if (m_kernel_version.find("stext=") == std::string::npos)
        return LLDB_INVALID_ADDRESS;
    size_t p = m_kernel_version.find("stext=") + strlen ("stext=");
    if (m_kernel_version[p] != '0' || m_kernel_version[p + 1] != 'x')
        return LLDB_INVALID_ADDRESS;

    addr_t kernel_load_address;
    errno = 0;
    kernel_load_address = ::strtoul (m_kernel_version.c_str() + p, NULL, 16);
    if (errno != 0 || kernel_load_address == 0)
        return LLDB_INVALID_ADDRESS;

    return kernel_load_address;
}

bool
CommunicationKDP::SendRequestHostInfo ()
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_HOSTINFO;
    const uint32_t command_length = 8;
    MakeRequestPacketHeader (command, request_packet, command_length);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        lldb::offset_t offset = 8;
        m_kdp_hostinfo_cpu_mask     = reply_packet.GetU32 (&offset);
        m_kdp_hostinfo_cpu_type     = reply_packet.GetU32 (&offset);
        m_kdp_hostinfo_cpu_subtype  = reply_packet.GetU32 (&offset);
        
        ArchSpec kernel_arch;
        kernel_arch.SetArchitecture (eArchTypeMachO, 
                                     m_kdp_hostinfo_cpu_type, 
                                     m_kdp_hostinfo_cpu_subtype);
    
        m_addr_byte_size = kernel_arch.GetAddressByteSize();
        m_byte_order = kernel_arch.GetByteOrder();
        return true;
    }
    return false;
}

const char *
CommunicationKDP::GetKernelVersion ()
{
    if (m_kernel_version.empty())
        SendRequestKernelVersion ();
    return m_kernel_version.c_str();
}

bool
CommunicationKDP::SendRequestKernelVersion ()
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_KERNELVERSION;
    const uint32_t command_length = 8;
    MakeRequestPacketHeader (command, request_packet, command_length);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        const char *kernel_version_cstr = reply_packet.PeekCStr(8);
        if (kernel_version_cstr && kernel_version_cstr[0])
            m_kernel_version.assign (kernel_version_cstr);
        return true;
    }
    return false;
}

bool
CommunicationKDP::SendRequestDisconnect ()
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_DISCONNECT;
    const uint32_t command_length = 8;
    MakeRequestPacketHeader (command, request_packet, command_length);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        // Are we supposed to get a reply for disconnect?
    }
    ClearKDPSettings ();
    return true;
}

uint32_t
CommunicationKDP::SendRequestReadMemory (lldb::addr_t addr, 
                                         void *dst, 
                                         uint32_t dst_len,
                                         Error &error)
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    bool use_64 = (GetVersion() >= 11);
    uint32_t command_addr_byte_size = use_64 ? 8 : 4;
    const CommandType command = use_64 ? KDP_READMEM64 : KDP_READMEM;
    // Size is header + address size + uint32_t length
    const uint32_t command_length = 8 + command_addr_byte_size + 4;
    MakeRequestPacketHeader (command, request_packet, command_length);
    request_packet.PutMaxHex64 (addr, command_addr_byte_size);
    request_packet.PutHex32 (dst_len);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        lldb::offset_t offset = 8;
        uint32_t kdp_error = reply_packet.GetU32 (&offset);
        uint32_t src_len = reply_packet.GetByteSize() - 12;
        
        if (src_len > 0)
        {
            const void *src = reply_packet.GetData(&offset, src_len);
            if (src)
            {
                ::memcpy (dst, src, src_len);
                error.Clear();
                return src_len;
            }
        }
        if (kdp_error)
            error.SetErrorStringWithFormat ("kdp read memory failed (error %u)", kdp_error);
        else
            error.SetErrorString ("kdp read memory failed");
    }
    else
    {
        error.SetErrorString ("failed to send packet");
    }
    return 0;
}


uint32_t
CommunicationKDP::SendRequestWriteMemory (lldb::addr_t addr, 
                                          const void *src, 
                                          uint32_t src_len,
                                          Error &error)
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    bool use_64 = (GetVersion() >= 11);
    uint32_t command_addr_byte_size = use_64 ? 8 : 4;
    const CommandType command = use_64 ? KDP_WRITEMEM64 : KDP_WRITEMEM;
    // Size is header + address size + uint32_t length
    const uint32_t command_length = 8 + command_addr_byte_size + 4 + src_len;
    MakeRequestPacketHeader (command, request_packet, command_length);
    request_packet.PutMaxHex64 (addr, command_addr_byte_size);
    request_packet.PutHex32 (src_len);
    request_packet.PutRawBytes(src, src_len);

    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        lldb::offset_t offset = 8;
        uint32_t kdp_error = reply_packet.GetU32 (&offset);
        if (kdp_error)
            error.SetErrorStringWithFormat ("kdp write memory failed (error %u)", kdp_error);
        else
        {
            error.Clear();
            return src_len;
        }
    }
    else
    {
        error.SetErrorString ("failed to send packet");
    }
    return 0;
}

bool
CommunicationKDP::SendRawRequest (uint8_t command_byte,
                                  const void *src,  // Raw packet payload bytes
                                  uint32_t src_len, // Raw packet payload length
                                  DataExtractor &reply_packet,
                                  Error &error)
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    // Size is header + address size + uint32_t length
    const uint32_t command_length = 8 + src_len;
    const CommandType command = (CommandType)command_byte;
    MakeRequestPacketHeader (command, request_packet, command_length);
    request_packet.PutRawBytes(src, src_len);
    
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        lldb::offset_t offset = 8;
        uint32_t kdp_error = reply_packet.GetU32 (&offset);
        if (kdp_error  && (command_byte != KDP_DUMPINFO))
            error.SetErrorStringWithFormat ("request packet 0x%8.8x failed (error %u)", command_byte, kdp_error);
        else
        {
            error.Clear();
            return true;
        }
    }
    else
    {
        error.SetErrorString ("failed to send packet");
    }
    return false;
}


const char *
CommunicationKDP::GetCommandAsCString (uint8_t command)
{
    switch (command)
    {
    case KDP_CONNECT:               return "KDP_CONNECT";
    case KDP_DISCONNECT:            return "KDP_DISCONNECT";
    case KDP_HOSTINFO:              return "KDP_HOSTINFO";
    case KDP_VERSION:               return "KDP_VERSION";
    case KDP_MAXBYTES:              return "KDP_MAXBYTES";
    case KDP_READMEM:               return "KDP_READMEM";
    case KDP_WRITEMEM:              return "KDP_WRITEMEM";
    case KDP_READREGS:              return "KDP_READREGS";
    case KDP_WRITEREGS:             return "KDP_WRITEREGS";
    case KDP_LOAD:                  return "KDP_LOAD";
    case KDP_IMAGEPATH:             return "KDP_IMAGEPATH";
    case KDP_SUSPEND:               return "KDP_SUSPEND";
    case KDP_RESUMECPUS:            return "KDP_RESUMECPUS";
    case KDP_EXCEPTION:             return "KDP_EXCEPTION";
    case KDP_TERMINATION:           return "KDP_TERMINATION";
    case KDP_BREAKPOINT_SET:        return "KDP_BREAKPOINT_SET";
    case KDP_BREAKPOINT_REMOVE:     return "KDP_BREAKPOINT_REMOVE";
    case KDP_REGIONS:               return "KDP_REGIONS";
    case KDP_REATTACH:              return "KDP_REATTACH";
    case KDP_HOSTREBOOT:            return "KDP_HOSTREBOOT";
    case KDP_READMEM64:             return "KDP_READMEM64";
    case KDP_WRITEMEM64:            return "KDP_WRITEMEM64";
    case KDP_BREAKPOINT_SET64:      return "KDP_BREAKPOINT64_SET";
    case KDP_BREAKPOINT_REMOVE64:   return "KDP_BREAKPOINT64_REMOVE";
    case KDP_KERNELVERSION:         return "KDP_KERNELVERSION";
    case KDP_READPHYSMEM64:         return "KDP_READPHYSMEM64";
    case KDP_WRITEPHYSMEM64:        return "KDP_WRITEPHYSMEM64";
    case KDP_READIOPORT:            return "KDP_READIOPORT";
    case KDP_WRITEIOPORT:           return "KDP_WRITEIOPORT";
    case KDP_READMSR64:             return "KDP_READMSR64";
    case KDP_WRITEMSR64:            return "KDP_WRITEMSR64";
    case KDP_DUMPINFO:              return "KDP_DUMPINFO";
    }
    return NULL;
}

void
CommunicationKDP::DumpPacket (Stream &s, const void *data, uint32_t data_len)
{
    DataExtractor extractor (data, data_len, m_byte_order, m_addr_byte_size);
    DumpPacket (s, extractor);
}

void
CommunicationKDP::DumpPacket (Stream &s, const DataExtractor& packet)
{
    const char *error_desc = NULL;
    if (packet.GetByteSize() < 8)
    {
        error_desc = "error: invalid packet (too short): ";
    }
    else
    {
        lldb::offset_t offset = 0;
        const uint8_t first_packet_byte = packet.GetU8 (&offset);
        const uint8_t sequence_id = packet.GetU8 (&offset);
        const uint16_t length = packet.GetU16 (&offset);
        const uint32_t key = packet.GetU32 (&offset);
        const CommandType command = ExtractCommand (first_packet_byte);
        const char *command_name = GetCommandAsCString (command);
        if (command_name)
        {
            const bool is_reply = ExtractIsReply(first_packet_byte);
            s.Printf ("(running=%i) %s %24s: 0x%2.2x 0x%2.2x 0x%4.4x 0x%8.8x ",
                      IsRunning(),
                      is_reply ? "<--" : "-->",
                      command_name,
                      first_packet_byte,
                      sequence_id,
                      length,
                      key);
            
            if (is_reply)
            {
                // Dump request reply packets
                switch (command)
                {
                    // Commands that return a single 32 bit error
                    case KDP_CONNECT:
                    case KDP_WRITEMEM:
                    case KDP_WRITEMEM64:
                    case KDP_BREAKPOINT_SET:
                    case KDP_BREAKPOINT_REMOVE:
                    case KDP_BREAKPOINT_SET64:
                    case KDP_BREAKPOINT_REMOVE64:
                    case KDP_WRITEREGS:
                    case KDP_LOAD:
                    case KDP_WRITEIOPORT:
                    case KDP_WRITEMSR64:
                        {
                            const uint32_t error = packet.GetU32 (&offset);
                            s.Printf(" (error=0x%8.8x)", error);
                        }
                        break;
                    
                    case KDP_DISCONNECT:
                    case KDP_REATTACH:
                    case KDP_HOSTREBOOT:
                    case KDP_SUSPEND:
                    case KDP_RESUMECPUS:
                    case KDP_EXCEPTION:
                    case KDP_TERMINATION:
                        // No return value for the reply, just the header to ack
                        s.PutCString(" ()");
                        break;

                    case KDP_HOSTINFO:
                        {
                            const uint32_t cpu_mask = packet.GetU32 (&offset);
                            const uint32_t cpu_type = packet.GetU32 (&offset);
                            const uint32_t cpu_subtype = packet.GetU32 (&offset);
                            s.Printf(" (cpu_mask=0x%8.8x, cpu_type=0x%8.8x, cpu_subtype=0x%8.8x)", cpu_mask, cpu_type, cpu_subtype);
                        }
                        break;
                        
                    case KDP_VERSION:
                        {
                            const uint32_t version = packet.GetU32 (&offset);
                            const uint32_t feature = packet.GetU32 (&offset);
                            s.Printf(" (version=0x%8.8x, feature=0x%8.8x)", version, feature);
                        }
                        break;
                        
                    case KDP_REGIONS:
                        {
                            const uint32_t region_count = packet.GetU32 (&offset);
                            s.Printf(" (count = %u", region_count); 
                            for (uint32_t i=0; i<region_count; ++i)
                            {
                                const addr_t region_addr = packet.GetPointer (&offset);
                                const uint32_t region_size = packet.GetU32 (&offset);
                                const uint32_t region_prot = packet.GetU32 (&offset);
                                s.Printf("\n\tregion[%" PRIu64 "] = { range = [0x%16.16" PRIx64 " - 0x%16.16" PRIx64 "), size = 0x%8.8x, prot = %s }", region_addr, region_addr, region_addr + region_size, region_size, GetPermissionsAsCString (region_prot));
                            }
                        }
                        break;

                    case KDP_READMEM:
                    case KDP_READMEM64:
                    case KDP_READPHYSMEM64:
                        {
                            const uint32_t error = packet.GetU32 (&offset);
                            const uint32_t count = packet.GetByteSize() - offset;
                            s.Printf(" (error = 0x%8.8x:\n", error); 
                            if (count > 0)
                                packet.Dump (&s,                        // Stream to dump to
                                             offset,                    // Offset within "packet"
                                             eFormatBytesWithASCII,     // Format to use
                                             1,                         // Size of each item in bytes
                                             count,                     // Number of items
                                             16,                        // Number per line
                                             m_last_read_memory_addr,   // Don't show addresses before each line
                                             0, 0);                     // No bitfields
                        }
                        break;

                    case KDP_READREGS:
                        {
                            const uint32_t error = packet.GetU32 (&offset);
                            const uint32_t count = packet.GetByteSize() - offset;
                            s.Printf(" (error = 0x%8.8x regs:\n", error); 
                            if (count > 0)
                                packet.Dump (&s,                        // Stream to dump to
                                             offset,                    // Offset within "packet"
                                             eFormatHex,                // Format to use
                                             m_addr_byte_size,          // Size of each item in bytes
                                             count / m_addr_byte_size,  // Number of items
                                             16 / m_addr_byte_size,     // Number per line
                                             LLDB_INVALID_ADDRESS,      // Don't show addresses before each line
                                             0, 0);                     // No bitfields
                        }
                        break;

                    case KDP_KERNELVERSION:
                        {
                            const char *kernel_version = packet.PeekCStr(8);
                            s.Printf(" (version = \"%s\")", kernel_version);
                        }
                        break;
                        
                    case KDP_MAXBYTES:
                        {
                            const uint32_t max_bytes = packet.GetU32 (&offset);
                            s.Printf(" (max_bytes = 0x%8.8x (%u))", max_bytes, max_bytes);
                        }
                        break;
                    case KDP_IMAGEPATH:
                        {
                            const char *path = packet.GetCStr(&offset);
                            s.Printf(" (path = \"%s\")", path);
                        }
                        break;

                    case KDP_READIOPORT:
                    case KDP_READMSR64:
                        {
                            const uint32_t error = packet.GetU32 (&offset);
                            const uint32_t count = packet.GetByteSize() - offset;
                            s.Printf(" (error = 0x%8.8x io:\n", error); 
                            if (count > 0)
                                packet.Dump (&s,                        // Stream to dump to
                                             offset,                    // Offset within "packet"
                                             eFormatHex,                // Format to use
                                             1,                         // Size of each item in bytes
                                             count,                     // Number of items
                                             16,                        // Number per line
                                             LLDB_INVALID_ADDRESS,      // Don't show addresses before each line
                                             0, 0);                     // No bitfields
                        }
                        break;
                    case KDP_DUMPINFO:
                        {
                            const uint32_t count = packet.GetByteSize() - offset;
                            s.Printf(" (count = %u, bytes = \n", count);
                            if (count > 0)
                                packet.Dump (&s,                        // Stream to dump to
                                             offset,                    // Offset within "packet"
                                             eFormatHex,                // Format to use
                                             1,                         // Size of each item in bytes
                                             count,                     // Number of items
                                             16,                        // Number per line
                                             LLDB_INVALID_ADDRESS,      // Don't show addresses before each line
                                             0, 0);                     // No bitfields
                            
                        }
                        break;
                        
                    default:
                        s.Printf(" (add support for dumping this packet reply!!!"); 
                        break;
                    
                } 
            }
            else
            {
                // Dump request packets
                switch (command)
                {
                    case KDP_CONNECT:               
                        {
                            const uint16_t reply_port = ntohs(packet.GetU16 (&offset));
                            const uint16_t exc_port = ntohs(packet.GetU16 (&offset));
                            s.Printf(" (reply_port = %u, exc_port = %u, greeting = \"%s\")", reply_port, exc_port, packet.GetCStr(&offset));
                        }
                        break;
                                 
                    case KDP_DISCONNECT:
                    case KDP_HOSTREBOOT:
                    case KDP_HOSTINFO:
                    case KDP_VERSION:
                    case KDP_REGIONS:
                    case KDP_KERNELVERSION:
                    case KDP_MAXBYTES:
                    case KDP_IMAGEPATH:
                    case KDP_SUSPEND:
                        // No args, just the header in the request...
                        s.PutCString(" ()");
                        break;

                    case KDP_RESUMECPUS:
                        {
                            const uint32_t cpu_mask = packet.GetU32 (&offset);
                            s.Printf(" (cpu_mask = 0x%8.8x)", cpu_mask);
                        }
                        break;

                    case KDP_READMEM:
                        {
                            const uint32_t addr = packet.GetU32 (&offset);
                            const uint32_t size = packet.GetU32 (&offset);
                            s.Printf(" (addr = 0x%8.8x, size = %u)", addr, size);
                            m_last_read_memory_addr = addr;
                        }
                        break;

                    case KDP_WRITEMEM:
                        {
                            const uint32_t addr = packet.GetU32 (&offset);
                            const uint32_t size = packet.GetU32 (&offset);
                            s.Printf(" (addr = 0x%8.8x, size = %u, bytes = \n", addr, size);
                            if (size > 0)
                                DataExtractor::DumpHexBytes(&s, packet.GetData(&offset, size), size, 32, addr);
                        }
                        break;

                    case KDP_READMEM64:
                        {
                            const uint64_t addr = packet.GetU64 (&offset);
                            const uint32_t size = packet.GetU32 (&offset);
                            s.Printf(" (addr = 0x%16.16" PRIx64 ", size = %u)", addr, size);
                            m_last_read_memory_addr = addr;
                        }
                        break;

                    case KDP_READPHYSMEM64:
                        {
                            const uint64_t addr = packet.GetU64 (&offset);
                            const uint32_t size = packet.GetU32 (&offset);
                            const uint32_t lcpu = packet.GetU16 (&offset);
                            s.Printf(" (addr = 0x%16.16llx, size = %u, lcpu = %u)", addr, size, lcpu);
                            m_last_read_memory_addr = addr;
                        }
                        break;

                    case KDP_WRITEMEM64:
                        {
                            const uint64_t addr = packet.GetU64 (&offset);
                            const uint32_t size = packet.GetU32 (&offset);
                            s.Printf(" (addr = 0x%16.16" PRIx64 ", size = %u, bytes = \n", addr, size);
                            if (size > 0)
                                DataExtractor::DumpHexBytes(&s, packet.GetData(&offset, size), size, 32, addr);
                        }
                        break;

                    case KDP_WRITEPHYSMEM64:
                        {
                            const uint64_t addr = packet.GetU64 (&offset);
                            const uint32_t size = packet.GetU32 (&offset);
                            const uint32_t lcpu = packet.GetU16 (&offset);
                            s.Printf(" (addr = 0x%16.16llx, size = %u, lcpu = %u, bytes = \n", addr, size, lcpu);
                            if (size > 0)
                                DataExtractor::DumpHexBytes(&s, packet.GetData(&offset, size), size, 32, addr);
                        }
                        break;

                    case KDP_READREGS:
                        {
                            const uint32_t cpu = packet.GetU32 (&offset);
                            const uint32_t flavor = packet.GetU32 (&offset);
                            s.Printf(" (cpu = %u, flavor = %u)", cpu, flavor);
                        }
                        break;

                    case KDP_WRITEREGS:
                        {
                            const uint32_t cpu = packet.GetU32 (&offset);
                            const uint32_t flavor = packet.GetU32 (&offset);
                            const uint32_t nbytes = packet.GetByteSize() - offset;
                            s.Printf(" (cpu = %u, flavor = %u, regs = \n", cpu, flavor);
                            if (nbytes > 0)
                                packet.Dump (&s,                        // Stream to dump to
                                             offset,                    // Offset within "packet"
                                             eFormatHex,                // Format to use
                                             m_addr_byte_size,          // Size of each item in bytes
                                             nbytes / m_addr_byte_size, // Number of items
                                             16 / m_addr_byte_size,     // Number per line
                                             LLDB_INVALID_ADDRESS,      // Don't show addresses before each line
                                             0, 0);                     // No bitfields
                        }
                        break;


                    case KDP_BREAKPOINT_SET:
                    case KDP_BREAKPOINT_REMOVE:
                        {
                            const uint32_t addr = packet.GetU32 (&offset);
                            s.Printf(" (addr = 0x%8.8x)", addr);
                        }
                        break;

                    case KDP_BREAKPOINT_SET64:
                    case KDP_BREAKPOINT_REMOVE64:
                        {
                            const uint64_t addr = packet.GetU64 (&offset);
                            s.Printf(" (addr = 0x%16.16" PRIx64 ")", addr);
                        }
                        break;


                    case KDP_LOAD:
                        {
                            const char *path = packet.GetCStr(&offset);
                            s.Printf(" (path = \"%s\")", path);
                        }
                        break;

                    case KDP_EXCEPTION:
                        {
                            const uint32_t count = packet.GetU32 (&offset);
                            
                            for (uint32_t i=0; i<count; ++i)
                            {
                                const uint32_t cpu = packet.GetU32 (&offset);
                                const uint32_t exc = packet.GetU32 (&offset);
                                const uint32_t code = packet.GetU32 (&offset);
                                const uint32_t subcode = packet.GetU32 (&offset);
                                const char *exc_cstr = NULL;
                                switch (exc)
                                {
                                    case 1:  exc_cstr = "EXC_BAD_ACCESS"; break;
                                    case 2:  exc_cstr = "EXC_BAD_INSTRUCTION"; break;
                                    case 3:  exc_cstr = "EXC_ARITHMETIC"; break;
                                    case 4:  exc_cstr = "EXC_EMULATION"; break;
                                    case 5:  exc_cstr = "EXC_SOFTWARE"; break;
                                    case 6:  exc_cstr = "EXC_BREAKPOINT"; break;
                                    case 7:  exc_cstr = "EXC_SYSCALL"; break;
                                    case 8:  exc_cstr = "EXC_MACH_SYSCALL"; break;
                                    case 9:  exc_cstr = "EXC_RPC_ALERT"; break;
                                    case 10: exc_cstr = "EXC_CRASH"; break;
                                    default:
                                        break;
                                }

                                s.Printf ("{ cpu = 0x%8.8x, exc = %s (%u), code = %u (0x%8.8x), subcode = %u (0x%8.8x)} ", 
                                          cpu, exc_cstr, exc, code, code, subcode, subcode);
                            }
                        }
                        break;

                    case KDP_TERMINATION:
                        {
                            const uint32_t term_code = packet.GetU32 (&offset);
                            const uint32_t exit_code = packet.GetU32 (&offset);
                            s.Printf(" (term_code = 0x%8.8x (%u), exit_code = 0x%8.8x (%u))", term_code, term_code, exit_code, exit_code);
                        }
                        break;

                    case KDP_REATTACH:
                        {
                            const uint16_t reply_port = ntohs(packet.GetU16 (&offset));
                            s.Printf(" (reply_port = %u)", reply_port);
                        }
                        break;

                    case KDP_READMSR64:
                        {
                            const uint32_t address = packet.GetU32 (&offset);
                            const uint16_t lcpu = packet.GetU16 (&offset);
                            s.Printf(" (address=0x%8.8x, lcpu=0x%4.4x)", address, lcpu);
                        }
                        break;

                    case KDP_WRITEMSR64:
                        {
                            const uint32_t address = packet.GetU32 (&offset);
                            const uint16_t lcpu = packet.GetU16 (&offset);
                            const uint32_t nbytes = packet.GetByteSize() - offset;
                            s.Printf(" (address=0x%8.8x, lcpu=0x%4.4x, nbytes=0x%8.8x)", lcpu, address, nbytes);
                            if (nbytes > 0)
                                packet.Dump (&s,                        // Stream to dump to
                                             offset,                    // Offset within "packet"
                                             eFormatHex,                // Format to use
                                             1,                         // Size of each item in bytes
                                             nbytes,                    // Number of items
                                             16,                        // Number per line
                                             LLDB_INVALID_ADDRESS,      // Don't show addresses before each line
                                             0, 0);                     // No bitfields
                        }
                        break;

                    case KDP_READIOPORT:
                        {
                            const uint16_t lcpu = packet.GetU16 (&offset);
                            const uint16_t address = packet.GetU16 (&offset);
                            const uint16_t nbytes = packet.GetU16 (&offset);
                            s.Printf(" (lcpu=0x%4.4x, address=0x%4.4x, nbytes=%u)", lcpu, address, nbytes);
                        }
                        break;

                    case KDP_WRITEIOPORT:
                         {
                            const uint16_t lcpu = packet.GetU16 (&offset);
                            const uint16_t address = packet.GetU16 (&offset);
                            const uint16_t nbytes = packet.GetU16 (&offset);
                            s.Printf(" (lcpu = %u, addr = 0x%4.4x, nbytes = %u, bytes = \n", lcpu, address, nbytes);
                            if (nbytes > 0)
                                packet.Dump (&s,                        // Stream to dump to
                                             offset,                    // Offset within "packet"
                                             eFormatHex,                // Format to use
                                             1,                         // Size of each item in bytes
                                             nbytes,                    // Number of items
                                             16,                        // Number per line
                                             LLDB_INVALID_ADDRESS,      // Don't show addresses before each line
                                             0, 0);                     // No bitfields
                        }
                        break;
                        
                    case KDP_DUMPINFO:
                        {
                            const uint32_t count = packet.GetByteSize() - offset;
                            s.Printf(" (count = %u, bytes = \n", count);
                            if (count > 0)
                                packet.Dump (&s,                        // Stream to dump to
                                             offset,                    // Offset within "packet"
                                             eFormatHex,                // Format to use
                                             1,                         // Size of each item in bytes
                                             count,                     // Number of items
                                             16,                        // Number per line
                                             LLDB_INVALID_ADDRESS,      // Don't show addresses before each line
                                             0, 0);                     // No bitfields
                            
                        }
                        break;
                        
               }
            }
        }
        else
        {
            error_desc = "error: invalid packet command: ";
        }
    }

    if (error_desc)
    {
        s.PutCString (error_desc);

        packet.Dump (&s,                    // Stream to dump to
                     0,                     // Offset into "packet"
                     eFormatBytes,          // Dump as hex bytes
                     1,                     // Size of each item is 1 for single bytes
                     packet.GetByteSize(),  // Number of bytes
                     UINT32_MAX,            // Num bytes per line
                     LLDB_INVALID_ADDRESS,  // Base address
                     0, 0);                 // Bitfield info set to not do anything bitfield related
    }
}

uint32_t
CommunicationKDP::SendRequestReadRegisters (uint32_t cpu,
                                            uint32_t flavor,
                                            void *dst,
                                            uint32_t dst_len,
                                            Error &error)
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_READREGS;
    // Size is header + 4 byte cpu and 4 byte flavor
    const uint32_t command_length = 8 + 4 + 4;
    MakeRequestPacketHeader (command, request_packet, command_length);
    request_packet.PutHex32 (cpu);
    request_packet.PutHex32 (flavor);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        lldb::offset_t offset = 8;
        uint32_t kdp_error = reply_packet.GetU32 (&offset);
        uint32_t src_len = reply_packet.GetByteSize() - 12;
        
        if (src_len > 0)
        {
            const uint32_t bytes_to_copy = std::min<uint32_t>(src_len, dst_len);
            const void *src = reply_packet.GetData(&offset, bytes_to_copy);
            if (src)
            {
                ::memcpy (dst, src, bytes_to_copy);
                error.Clear();
                // Return the number of bytes we could have returned regardless if
                // we copied them or not, just so we know when things don't match up
                return src_len;
            }
        }
        if (kdp_error)
            error.SetErrorStringWithFormat("failed to read kdp registers for cpu %u flavor %u (error %u)", cpu, flavor, kdp_error);
        else
            error.SetErrorStringWithFormat("failed to read kdp registers for cpu %u flavor %u", cpu, flavor);
    }
    else
    {
        error.SetErrorString ("failed to send packet");
    }
    return 0;
}

uint32_t
CommunicationKDP::SendRequestWriteRegisters (uint32_t cpu,
                                             uint32_t flavor,
                                             const void *src,
                                             uint32_t src_len,
                                             Error &error)
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_WRITEREGS;
    // Size is header + 4 byte cpu and 4 byte flavor
    const uint32_t command_length = 8 + 4 + 4 + src_len;
    MakeRequestPacketHeader (command, request_packet, command_length);
    request_packet.PutHex32 (cpu);
    request_packet.PutHex32 (flavor);
    request_packet.Write(src, src_len);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        lldb::offset_t offset = 8;
        uint32_t kdp_error = reply_packet.GetU32 (&offset);
        if (kdp_error == 0)
            return src_len;
        error.SetErrorStringWithFormat("failed to read kdp registers for cpu %u flavor %u (error %u)", cpu, flavor, kdp_error);
    }
    else
    {
        error.SetErrorString ("failed to send packet");
    }
    return 0;
}


bool
CommunicationKDP::SendRequestResume ()
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_RESUMECPUS;
    const uint32_t command_length = 12;
    MakeRequestPacketHeader (command, request_packet, command_length);
    request_packet.PutHex32(GetCPUMask());

    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
        return true;
    return false;
}

bool
CommunicationKDP::SendRequestBreakpoint (bool set, addr_t addr)
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    bool use_64 = (GetVersion() >= 11);
    uint32_t command_addr_byte_size = use_64 ? 8 : 4;
    const CommandType command = set ? (use_64 ? KDP_BREAKPOINT_SET64    : KDP_BREAKPOINT_SET   ):
                                      (use_64 ? KDP_BREAKPOINT_REMOVE64 : KDP_BREAKPOINT_REMOVE);

    const uint32_t command_length = 8 + command_addr_byte_size;
    MakeRequestPacketHeader (command, request_packet, command_length);
    request_packet.PutMaxHex64 (addr, command_addr_byte_size);
    
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
    {
        lldb::offset_t offset = 8;
        uint32_t kdp_error = reply_packet.GetU32 (&offset);        
        if (kdp_error == 0)
            return true;
    }
    return false;
}

bool
CommunicationKDP::SendRequestSuspend ()
{
    PacketStreamType request_packet (Stream::eBinary, m_addr_byte_size, m_byte_order);
    const CommandType command = KDP_SUSPEND;
    const uint32_t command_length = 8;
    MakeRequestPacketHeader (command, request_packet, command_length);
    DataExtractor reply_packet;
    if (SendRequestAndGetReply (command, request_packet, reply_packet))
        return true;
    return false;
}