lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp

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

#include "lldb/Breakpoint/StoppointCallbackContext.h"
#include "lldb/Core/DataBuffer.h"
#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/State.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Target/ObjCLanguageRuntime.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlanRunToAddress.h"
#include "lldb/Target/StackFrame.h"

#include "DynamicLoaderDarwinKernel.h"

//#define ENABLE_DEBUG_PRINTF // COMMENT THIS LINE OUT PRIOR TO CHECKIN
#ifdef ENABLE_DEBUG_PRINTF
#include <stdio.h>
#define DEBUG_PRINTF(fmt, ...) printf(fmt, ## __VA_ARGS__)
#else
#define DEBUG_PRINTF(fmt, ...)
#endif

using namespace lldb;
using namespace lldb_private;

/// FIXME - The ObjC Runtime trampoline handler doesn't really belong here.
/// I am putting it here so I can invoke it in the Trampoline code here, but
/// it should be moved to the ObjC Runtime support when it is set up.


//----------------------------------------------------------------------
// Create an instance of this class. This function is filled into
// the plugin info class that gets handed out by the plugin factory and
// allows the lldb to instantiate an instance of this class.
//----------------------------------------------------------------------
DynamicLoader *
DynamicLoaderDarwinKernel::CreateInstance (Process* process, bool force)
{
    bool create = force;
    if (!create)
    {
        Module* exe_module = process->GetTarget().GetExecutableModulePointer();
        if (exe_module)
        {
            ObjectFile *object_file = exe_module->GetObjectFile();
            if (object_file)
            {
                create = (object_file->GetStrata() == ObjectFile::eStrataKernel);
            }
        }
        
        if (create)
        {
            const llvm::Triple &triple_ref = process->GetTarget().GetArchitecture().GetTriple();
            create = triple_ref.getOS() == llvm::Triple::Darwin && triple_ref.getVendor() == llvm::Triple::Apple;
        }
    }
    
    if (create)
    {
        process->SetCanJIT(false);
        return new DynamicLoaderDarwinKernel (process);
    }
    return NULL;
}

//----------------------------------------------------------------------
// Constructor
//----------------------------------------------------------------------
DynamicLoaderDarwinKernel::DynamicLoaderDarwinKernel (Process* process) :
    DynamicLoader(process),
    m_kernel(),
    m_kext_summary_header_ptr_addr (),
    m_kext_summary_header_addr (),
    m_kext_summary_header (),
    m_kext_summaries(),
    m_mutex(Mutex::eMutexTypeRecursive),
    m_break_id (LLDB_INVALID_BREAK_ID)
{
}

//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
DynamicLoaderDarwinKernel::~DynamicLoaderDarwinKernel()
{
    Clear(true);
}

void
DynamicLoaderDarwinKernel::UpdateIfNeeded()
{
    LoadKernelModuleIfNeeded();
    SetNotificationBreakpointIfNeeded ();
}
//------------------------------------------------------------------
/// Called after attaching a process.
///
/// Allow DynamicLoader plug-ins to execute some code after
/// attaching to a process.
//------------------------------------------------------------------
void
DynamicLoaderDarwinKernel::DidAttach ()
{
    PrivateInitialize(m_process);
    UpdateIfNeeded();
}

//------------------------------------------------------------------
/// Called after attaching a process.
///
/// Allow DynamicLoader plug-ins to execute some code after
/// attaching to a process.
//------------------------------------------------------------------
void
DynamicLoaderDarwinKernel::DidLaunch ()
{
    PrivateInitialize(m_process);
    UpdateIfNeeded();
}


//----------------------------------------------------------------------
// Clear out the state of this class.
//----------------------------------------------------------------------
void
DynamicLoaderDarwinKernel::Clear (bool clear_process)
{
    Mutex::Locker locker(m_mutex);

    if (m_process->IsAlive() && LLDB_BREAK_ID_IS_VALID(m_break_id))
        m_process->ClearBreakpointSiteByID(m_break_id);

    if (clear_process)
        m_process = NULL;
    m_kernel.Clear(false);
    m_kext_summary_header_ptr_addr.Clear();
    m_kext_summary_header_addr.Clear();
    m_kext_summaries.clear();
    m_break_id = LLDB_INVALID_BREAK_ID;
}


bool
DynamicLoaderDarwinKernel::OSKextLoadedKextSummary::LoadImageAtFileAddress (Process *process)
{
    if (IsLoaded())
        return true;

    if (module_sp)
    {
        bool changed = false;
        if (module_sp->SetLoadAddress (process->GetTarget(), 0, changed))
            load_process_stop_id = process->GetStopID();
    }
    return false;
}

bool
DynamicLoaderDarwinKernel::OSKextLoadedKextSummary::LoadImageUsingMemoryModule (Process *process)
{
    if (IsLoaded())
        return true;

    bool uuid_is_valid = uuid.IsValid();

    Target &target = process->GetTarget();
    ModuleSP memory_module_sp;
    // Use the memory module as the module if we have one...
    if (address != LLDB_INVALID_ADDRESS)
    {
        FileSpec file_spec;
        if (module_sp)
            file_spec = module_sp->GetFileSpec();
        else
            file_spec.SetFile (name, false);
        
        memory_module_sp = process->ReadModuleFromMemory (file_spec, address, false, false);
        if (memory_module_sp && !uuid_is_valid)
        {
            uuid = memory_module_sp->GetUUID();
            uuid_is_valid = uuid.IsValid();
        }
    }

    if (!module_sp)
    {
        bool uuid_is_valid = uuid.IsValid();
        if (uuid_is_valid)
        {
            ModuleList &target_images = target.GetImages();
            module_sp = target_images.FindModule(uuid);
            
            if (!module_sp)
            {
                ModuleSpec module_spec;
                module_spec.GetUUID() = uuid;
                module_sp = target.GetSharedModule (module_spec);
            }
        }
    }
    

    if (memory_module_sp)
    {
        // Someone already supplied a file, make sure it is the right one.
        if (module_sp)
        {
            if (module_sp->GetUUID() == memory_module_sp->GetUUID())
            {
                ObjectFile *ondisk_object_file = module_sp->GetObjectFile();
                ObjectFile *memory_object_file = memory_module_sp->GetObjectFile();
                if (memory_object_file && ondisk_object_file)
                {
                    SectionList *ondisk_section_list = ondisk_object_file->GetSectionList ();
                    SectionList *memory_section_list = memory_object_file->GetSectionList ();
                    if (memory_section_list && ondisk_section_list)
                    {
                        const uint32_t num_ondisk_sections = ondisk_section_list->GetSize();
                        // There may be CTF sections in the memory image so we can't
                        // always just compare the number of sections (which are actually
                        // segments in mach-o parlance)
                        uint32_t sect_idx = 0;
                        
                        
                        // We now iterate through all sections in the file module 
                        // and look to see if the memory module has a load address
                        // for that section.
                        uint32_t num_sections_loaded = 0;
                        for (sect_idx=0; sect_idx<num_ondisk_sections; ++sect_idx)
                        {
                            const Section *ondisk_section = ondisk_section_list->GetSectionAtIndex(sect_idx).get();
                            if (ondisk_section)
                            {
                                const Section *memory_section = memory_section_list->FindSectionByName(ondisk_section->GetName()).get();
                                if (memory_section)
                                {
                                    target.GetSectionLoadList().SetSectionLoadAddress (ondisk_section, memory_section->GetFileAddress());
                                    ++num_sections_loaded;
                                }
                            }
                        }
                        if (num_sections_loaded > 0)
                            load_process_stop_id = process->GetStopID();
                        else
                            module_sp.reset(); // No sections were loaded
                    }
                    else
                        module_sp.reset(); // One or both section lists
                }
                else
                    module_sp.reset(); // One or both object files missing
            }
            else
                module_sp.reset(); // UUID mismatch
        }
        
        // Use the memory module as the module if we didn't like the file
        // module we either found or were supplied with
        if (!module_sp)
        {
            module_sp = memory_module_sp;
            // Load the memory image in the target as all adresses are already correct
            bool changed = false;
            target.GetImages().Append (memory_module_sp);
            if (module_sp->SetLoadAddress (target, 0, changed))
                load_process_stop_id = process->GetStopID();
        }
    }
    bool is_loaded = IsLoaded();
    
    if (so_address.IsValid())
    {
        if (is_loaded)
            so_address.SetLoadAddress (address, &target);
        else
            target.GetImages().ResolveFileAddress (address, so_address);

    }
    return is_loaded;
}

//----------------------------------------------------------------------
// Load the kernel module and initialize the "m_kernel" member. Return
// true _only_ if the kernel is loaded the first time through (subsequent
// calls to this function should return false after the kernel has been
// already loaded).
//----------------------------------------------------------------------
void
DynamicLoaderDarwinKernel::LoadKernelModuleIfNeeded()
{
    if (!m_kext_summary_header_ptr_addr.IsValid())
    {
        m_kernel.Clear(false);
        m_kernel.module_sp = m_process->GetTarget().GetExecutableModule();
        strncpy(m_kernel.name, "mach_kernel", sizeof(m_kernel.name));
        if (m_kernel.address == LLDB_INVALID_ADDRESS)
        {
            m_kernel.address = m_process->GetImageInfoAddress ();
            if (m_kernel.address == LLDB_INVALID_ADDRESS && m_kernel.module_sp)
            {
                // We didn't get a hint from the process, so we will
                // try the kernel at the address that it exists at in
                // the file if we have one
                ObjectFile *kernel_object_file = m_kernel.module_sp->GetObjectFile();
                if (kernel_object_file)
                    m_kernel.address = kernel_object_file->GetHeaderAddress().GetFileAddress();
            }
        }
        
        if (m_kernel.address != LLDB_INVALID_ADDRESS)
        {
            if (!m_kernel.LoadImageUsingMemoryModule (m_process))
            {
                m_kernel.LoadImageAtFileAddress (m_process);
            }
        }

        if (m_kernel.IsLoaded())
        {
            static ConstString kext_summary_symbol ("gLoadedKextSummaries");
            const Symbol *symbol = m_kernel.module_sp->FindFirstSymbolWithNameAndType (kext_summary_symbol, eSymbolTypeData);
            if (symbol)
            {
                m_kext_summary_header_ptr_addr = symbol->GetAddress();
                // Update all image infos
                ReadAllKextSummaries ();
            }
        }
        else
        {
            m_kernel.Clear(false);
        }
    }
}

//----------------------------------------------------------------------
// Static callback function that gets called when our DYLD notification
// breakpoint gets hit. We update all of our image infos and then
// let our super class DynamicLoader class decide if we should stop
// or not (based on global preference).
//----------------------------------------------------------------------
bool
DynamicLoaderDarwinKernel::BreakpointHitCallback (void *baton, 
                                                  StoppointCallbackContext *context, 
                                                  user_id_t break_id, 
                                                  user_id_t break_loc_id)
{    
    return static_cast<DynamicLoaderDarwinKernel*>(baton)->BreakpointHit (context, break_id, break_loc_id);    
}

bool
DynamicLoaderDarwinKernel::BreakpointHit (StoppointCallbackContext *context, 
                                          user_id_t break_id, 
                                          user_id_t break_loc_id)
{    
    LogSP log(GetLogIfAnyCategoriesSet (LIBLLDB_LOG_DYNAMIC_LOADER));
    if (log)
        log->Printf ("DynamicLoaderDarwinKernel::BreakpointHit (...)\n");

    ReadAllKextSummaries ();
    
    if (log)
        PutToLog(log.get());

    return GetStopWhenImagesChange();
}


bool
DynamicLoaderDarwinKernel::ReadKextSummaryHeader ()
{
    Mutex::Locker locker(m_mutex);

    // the all image infos is already valid for this process stop ID

    m_kext_summaries.clear();
    if (m_kext_summary_header_ptr_addr.IsValid())
    {
        const uint32_t addr_size = m_kernel.GetAddressByteSize ();
        const ByteOrder byte_order = m_kernel.GetByteOrder();
        Error error;
        // Read enough bytes for a "OSKextLoadedKextSummaryHeader" structure
        // which is currenty 4 uint32_t and a pointer.
        uint8_t buf[24];
        DataExtractor data (buf, sizeof(buf), byte_order, addr_size);
        const size_t count = 4 * sizeof(uint32_t) + addr_size;
        const bool prefer_file_cache = false;
        if (m_process->GetTarget().ReadPointerFromMemory (m_kext_summary_header_ptr_addr, 
                                                          prefer_file_cache,
                                                          error,
                                                          m_kext_summary_header_addr))
        {
            // We got a valid address for our kext summary header and make sure it isn't NULL
            if (m_kext_summary_header_addr.IsValid() && 
                m_kext_summary_header_addr.GetFileAddress() != 0)
            {
                const size_t bytes_read = m_process->GetTarget().ReadMemory (m_kext_summary_header_addr, prefer_file_cache, buf, count, error);
                if (bytes_read == count)
                {
                    uint32_t offset = 0;
                    m_kext_summary_header.version = data.GetU32(&offset);
                    if (m_kext_summary_header.version >= 2)
                    {
                        m_kext_summary_header.entry_size = data.GetU32(&offset);
                    }
                    else
                    {
                        // Versions less than 2 didn't have an entry size, it was hard coded
                        m_kext_summary_header.entry_size = KERNEL_MODULE_ENTRY_SIZE_VERSION_1;
                    }
                    m_kext_summary_header.entry_count = data.GetU32(&offset);
                    return true;
                }
            }
        }
    }
    m_kext_summary_header_addr.Clear();
    return false;
}


bool
DynamicLoaderDarwinKernel::ParseKextSummaries (const Address &kext_summary_addr, 
                                               uint32_t count)
{
    OSKextLoadedKextSummary::collection kext_summaries;
    LogSP log(GetLogIfAnyCategoriesSet (LIBLLDB_LOG_DYNAMIC_LOADER));
    if (log)
        log->Printf ("Adding %d modules.\n", count);
        
    Mutex::Locker locker(m_mutex);

    if (!ReadKextSummaries (kext_summary_addr, count, kext_summaries))
        return false;

    Stream *s = &m_process->GetTarget().GetDebugger().GetOutputStream();
    for (uint32_t i = 0; i < count; i++)
    {
        if (s)
        {
            const uint8_t *u = (const uint8_t *)kext_summaries[i].uuid.GetBytes();
            if (u)
            {
                s->Printf("Loading kext: %2.2X%2.2X%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X%2.2X%2.2X%2.2X%2.2X 0x%16.16llx \"%s\"...",
                          u[ 0], u[ 1], u[ 2], u[ 3], u[ 4], u[ 5], u[ 6], u[ 7],
                          u[ 8], u[ 9], u[10], u[11], u[12], u[13], u[14], u[15],
                          kext_summaries[i].address, kext_summaries[i].name);
            }   
            else
            {
                s->Printf("0x%16.16llx \"%s\"...", kext_summaries[i].address, kext_summaries[i].name);
            }
        }
        
        if (!kext_summaries[i].LoadImageUsingMemoryModule (m_process))
            kext_summaries[i].LoadImageAtFileAddress (m_process);

        if (s)
        {
            if (kext_summaries[i].module_sp)
            {
                if (kext_summaries[i].module_sp->GetFileSpec().GetDirectory())
                    s->Printf("\n  found kext: %s/%s\n", 
                              kext_summaries[i].module_sp->GetFileSpec().GetDirectory().AsCString(),
                              kext_summaries[i].module_sp->GetFileSpec().GetFilename().AsCString());
                else
                    s->Printf("\n  found kext: %s\n", 
                              kext_summaries[i].module_sp->GetFileSpec().GetFilename().AsCString());
            }
            else
                s->Printf (" failed to locate/load.\n");
        }
            
        if (log)
            kext_summaries[i].PutToLog (log.get());
    }
    bool return_value = AddModulesUsingImageInfos (kext_summaries);
    return return_value;
}

// Adds the modules in image_infos to m_kext_summaries.  
// NB don't call this passing in m_kext_summaries.

bool
DynamicLoaderDarwinKernel::AddModulesUsingImageInfos (OSKextLoadedKextSummary::collection &image_infos)
{
    // Now add these images to the main list.
    ModuleList loaded_module_list;
    
    for (uint32_t idx = 0; idx < image_infos.size(); ++idx)
    {
        OSKextLoadedKextSummary &image_info = image_infos[idx];
        m_kext_summaries.push_back(image_info);
        
        if (image_info.module_sp && m_process->GetStopID() == image_info.load_process_stop_id)
            loaded_module_list.AppendIfNeeded (image_infos[idx].module_sp);
    }
    
    if (loaded_module_list.GetSize() > 0)
    {
        m_process->GetTarget().ModulesDidLoad (loaded_module_list);
    }
    return true;
}


uint32_t
DynamicLoaderDarwinKernel::ReadKextSummaries (const Address &kext_summary_addr,
                                              uint32_t image_infos_count, 
                                              OSKextLoadedKextSummary::collection &image_infos)
{
    const ByteOrder endian = m_kernel.GetByteOrder();
    const uint32_t addr_size = m_kernel.GetAddressByteSize();

    image_infos.resize(image_infos_count);
    const size_t count = image_infos.size() * m_kext_summary_header.entry_size;
    DataBufferHeap data(count, 0);
    Error error;
    
    Stream *s = &m_process->GetTarget().GetDebugger().GetOutputStream();

    if (s)
        s->Printf ("Reading %u kext summaries...\n", image_infos_count);
    const bool prefer_file_cache = false;
    const size_t bytes_read = m_process->GetTarget().ReadMemory (kext_summary_addr, 
                                                                 prefer_file_cache,
                                                                 data.GetBytes(), 
                                                                 data.GetByteSize(),
                                                                 error);
    if (bytes_read == count)
    {
        
        DataExtractor extractor (data.GetBytes(), data.GetByteSize(), endian, addr_size);
        uint32_t i=0;
        for (uint32_t kext_summary_offset = 0;
             i < image_infos.size() && extractor.ValidOffsetForDataOfSize(kext_summary_offset, m_kext_summary_header.entry_size); 
             ++i, kext_summary_offset += m_kext_summary_header.entry_size)
        {
            uint32_t offset = kext_summary_offset;
            const void *name_data = extractor.GetData(&offset, KERNEL_MODULE_MAX_NAME);
            if (name_data == NULL)
                break;
            memcpy (image_infos[i].name, name_data, KERNEL_MODULE_MAX_NAME);
            image_infos[i].uuid.SetBytes(extractor.GetData (&offset, 16));
            image_infos[i].address          = extractor.GetU64(&offset);
            if (!image_infos[i].so_address.SetLoadAddress (image_infos[i].address, &m_process->GetTarget()))
                m_process->GetTarget().GetImages().ResolveFileAddress (image_infos[i].address, image_infos[i].so_address);
            image_infos[i].size             = extractor.GetU64(&offset);
            image_infos[i].version          = extractor.GetU64(&offset);
            image_infos[i].load_tag         = extractor.GetU32(&offset);
            image_infos[i].flags            = extractor.GetU32(&offset);
            if ((offset - kext_summary_offset) < m_kext_summary_header.entry_size)
            {
                image_infos[i].reference_list = extractor.GetU64(&offset);
            }
            else
            {
                image_infos[i].reference_list = 0;
            }
//            printf ("[%3u] %*.*s: address=0x%16.16llx, size=0x%16.16llx, version=0x%16.16llx, load_tag=0x%8.8x, flags=0x%8.8x\n", 
//                    i,
//                    KERNEL_MODULE_MAX_NAME, KERNEL_MODULE_MAX_NAME,  (char *)name_data, 
//                    image_infos[i].address, 
//                    image_infos[i].size,
//                    image_infos[i].version,
//                    image_infos[i].load_tag,
//                    image_infos[i].flags);
        }
        if (i < image_infos.size())
            image_infos.resize(i);
    }
    else
    {
        image_infos.clear();
    }
    return image_infos.size();
}

bool
DynamicLoaderDarwinKernel::ReadAllKextSummaries ()
{
    LogSP log(GetLogIfAnyCategoriesSet (LIBLLDB_LOG_DYNAMIC_LOADER));
    
    Mutex::Locker locker(m_mutex);
    
    if (ReadKextSummaryHeader ())
    {
        if (m_kext_summary_header.entry_count > 0 && m_kext_summary_header_addr.IsValid())
        {
            Address summary_addr (m_kext_summary_header_addr);
            summary_addr.Slide(m_kext_summary_header.GetSize());
            if (!ParseKextSummaries (summary_addr, m_kext_summary_header.entry_count))
            {
                m_kext_summaries.clear();
            }
            return true;
        }
    }
    return false;
}

//----------------------------------------------------------------------
// Dump an image info structure to the file handle provided.
//----------------------------------------------------------------------
void
DynamicLoaderDarwinKernel::OSKextLoadedKextSummary::PutToLog (Log *log) const
{
    if (log == NULL)
        return;
    const uint8_t *u = (uint8_t *)uuid.GetBytes();

    if (address == LLDB_INVALID_ADDRESS)
    {
        if (u)
        {
            log->Printf("\tuuid=%2.2X%2.2X%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X%2.2X%2.2X%2.2X%2.2X name=\"%s\" (UNLOADED)",
                        u[ 0], u[ 1], u[ 2], u[ 3],
                        u[ 4], u[ 5], u[ 6], u[ 7],
                        u[ 8], u[ 9], u[10], u[11],
                        u[12], u[13], u[14], u[15],
                        name);
        }
        else
            log->Printf("\tname=\"%s\" (UNLOADED)", name);
    }
    else
    {
        if (u)
        {
            log->Printf("\taddr=0x%16.16llx size=0x%16.16llx version=0x%16.16llx load-tag=0x%8.8x flags=0x%8.8x ref-list=0x%16.16llx uuid=%2.2X%2.2X%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X-%2.2X%2.2X%2.2X%2.2X%2.2X%2.2X name=\"%s\"",
                        address, size, version, load_tag, flags, reference_list,
                        u[ 0], u[ 1], u[ 2], u[ 3], u[ 4], u[ 5], u[ 6], u[ 7],
                        u[ 8], u[ 9], u[10], u[11], u[12], u[13], u[14], u[15],
                        name);
        }
        else
        {
            log->Printf("\t[0x%16.16llx - 0x%16.16llx) version=0x%16.16llx load-tag=0x%8.8x flags=0x%8.8x ref-list=0x%16.16llx name=\"%s\"",
                        address, address+size, version, load_tag, flags, reference_list,
                        name);
        }
    }
}

//----------------------------------------------------------------------
// Dump the _dyld_all_image_infos members and all current image infos
// that we have parsed to the file handle provided.
//----------------------------------------------------------------------
void
DynamicLoaderDarwinKernel::PutToLog(Log *log) const
{
    if (log == NULL)
        return;

    Mutex::Locker locker(m_mutex);
    log->Printf("gLoadedKextSummaries = 0x%16.16llx { version=%u, entry_size=%u, entry_count=%u }",
                m_kext_summary_header_addr.GetFileAddress(),
                m_kext_summary_header.version,
                m_kext_summary_header.entry_size,
                m_kext_summary_header.entry_count);

    size_t i;
    const size_t count = m_kext_summaries.size();
    if (count > 0)
    {
        log->PutCString("Loaded:");
        for (i = 0; i<count; i++)
            m_kext_summaries[i].PutToLog(log);
    }
}

void
DynamicLoaderDarwinKernel::PrivateInitialize(Process *process)
{
    DEBUG_PRINTF("DynamicLoaderDarwinKernel::%s() process state = %s\n", __FUNCTION__, StateAsCString(m_process->GetState()));
    Clear(true);
    m_process = process;
    m_process->GetTarget().GetSectionLoadList().Clear();
}

void
DynamicLoaderDarwinKernel::SetNotificationBreakpointIfNeeded ()
{
    if (m_break_id == LLDB_INVALID_BREAK_ID && m_kernel.module_sp)
    {
        DEBUG_PRINTF("DynamicLoaderDarwinKernel::%s() process state = %s\n", __FUNCTION__, StateAsCString(m_process->GetState()));

        
        const bool internal_bp = false;
        const LazyBool skip_prologue = eLazyBoolNo;
        FileSpecList module_spec_list;
        module_spec_list.Append (m_kernel.module_sp->GetFileSpec());
        Breakpoint *bp = m_process->GetTarget().CreateBreakpoint (&module_spec_list,
                                                                  NULL,
                                                                  "OSKextLoadedKextSummariesUpdated",
                                                                  eFunctionNameTypeFull,
                                                                  internal_bp,
                                                                  skip_prologue).get();

        bp->SetCallback (DynamicLoaderDarwinKernel::BreakpointHitCallback, this, true);
        m_break_id = bp->GetID();
    }
}

//----------------------------------------------------------------------
// Member function that gets called when the process state changes.
//----------------------------------------------------------------------
void
DynamicLoaderDarwinKernel::PrivateProcessStateChanged (Process *process, StateType state)
{
    DEBUG_PRINTF("DynamicLoaderDarwinKernel::%s(%s)\n", __FUNCTION__, StateAsCString(state));
    switch (state)
    {
    case eStateConnected:
    case eStateAttaching:
    case eStateLaunching:
    case eStateInvalid:
    case eStateUnloaded:
    case eStateExited:
    case eStateDetached:
        Clear(false);
        break;

    case eStateStopped:
        UpdateIfNeeded();
        break;

    case eStateRunning:
    case eStateStepping:
    case eStateCrashed:
    case eStateSuspended:
        break;

    default:
        break;
    }
}

ThreadPlanSP
DynamicLoaderDarwinKernel::GetStepThroughTrampolinePlan (Thread &thread, bool stop_others)
{
    ThreadPlanSP thread_plan_sp;
    LogSP log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
    if (log)
        log->Printf ("Could not find symbol for step through.");
    return thread_plan_sp;
}

Error
DynamicLoaderDarwinKernel::CanLoadImage ()
{
    Error error;
    error.SetErrorString("always unsafe to load or unload shared libraries in the darwin kernel");
    return error;
}

void
DynamicLoaderDarwinKernel::Initialize()
{
    PluginManager::RegisterPlugin (GetPluginNameStatic(),
                                   GetPluginDescriptionStatic(),
                                   CreateInstance);
}

void
DynamicLoaderDarwinKernel::Terminate()
{
    PluginManager::UnregisterPlugin (CreateInstance);
}


const char *
DynamicLoaderDarwinKernel::GetPluginNameStatic()
{
    return "dynamic-loader.macosx-kernel";
}

const char *
DynamicLoaderDarwinKernel::GetPluginDescriptionStatic()
{
    return "Dynamic loader plug-in that watches for shared library loads/unloads in the MacOSX kernel.";
}


//------------------------------------------------------------------
// PluginInterface protocol
//------------------------------------------------------------------
const char *
DynamicLoaderDarwinKernel::GetPluginName()
{
    return "DynamicLoaderDarwinKernel";
}

const char *
DynamicLoaderDarwinKernel::GetShortPluginName()
{
    return GetPluginNameStatic();
}

uint32_t
DynamicLoaderDarwinKernel::GetPluginVersion()
{
    return 1;
}