ObjectContainer/BSD-Archive/ObjectContainerBSDArchive.cpp

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

#include "ObjectContainerBSDArchive.h"

#include <ar.h>

#include "lldb/Core/ArchSpec.h"
#include "lldb/Core/DataBuffer.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Stream.h"
#include "lldb/Core/Timer.h"
#include "lldb/Host/Mutex.h"
#include "lldb/Symbol/ObjectFile.h"

using namespace lldb;
using namespace lldb_private;


ObjectContainerBSDArchive::Object::Object() :
    ar_name(),
    ar_date(0),
    ar_uid(0),
    ar_gid(0),
    ar_mode(0),
    ar_size(0),
    ar_file_offset(0),
    ar_file_size(0)
{
}

void
ObjectContainerBSDArchive::Object::Clear()
{
    ar_name.Clear();
    ar_date = 0;
    ar_uid  = 0;
    ar_gid  = 0;
    ar_mode = 0;
    ar_size = 0;
    ar_file_offset = 0;
    ar_file_size = 0;
}

lldb::offset_t
ObjectContainerBSDArchive::Object::Extract (const DataExtractor& data, lldb::offset_t offset)
{
    size_t ar_name_len = 0;
    std::string str;
    char *err;
    str.assign ((const char *)data.GetData(&offset, 16),    16);
    if (str.find("#1/") == 0)
    {
        // If the name is longer than 16 bytes, or contains an embedded space
        // then it will use this format where the length of the name is
        // here and the name characters are after this header.
        ar_name_len = strtoul(str.c_str() + 3, &err, 10);
    }
    else
    {
        // Strip off any spaces (if the object file name contains spaces it
        // will use the extended format above).
        str.erase (str.find(' '));
        ar_name.SetCString(str.c_str());
    }

    str.assign ((const char *)data.GetData(&offset, 12),    12);
    ar_date = strtoul(str.c_str(), &err, 10);

    str.assign ((const char *)data.GetData(&offset, 6), 6);
    ar_uid  = strtoul(str.c_str(), &err, 10);

    str.assign ((const char *)data.GetData(&offset, 6), 6);
    ar_gid  = strtoul(str.c_str(), &err, 10);

    str.assign ((const char *)data.GetData(&offset, 8), 8);
    ar_mode = strtoul(str.c_str(), &err, 8);

    str.assign ((const char *)data.GetData(&offset, 10),    10);
    ar_size = strtoul(str.c_str(), &err, 10);

    str.assign ((const char *)data.GetData(&offset, 2), 2);
    if (str == ARFMAG)
    {
        if (ar_name_len > 0)
        {
            str.assign ((const char *)data.GetData(&offset, ar_name_len), ar_name_len);
            ar_name.SetCString (str.c_str());
        }
        ar_file_offset = offset;
        ar_file_size = ar_size - ar_name_len;
        return offset;
    }
    return LLDB_INVALID_OFFSET;
}

ObjectContainerBSDArchive::Archive::Archive
(
    const lldb_private::ArchSpec &arch,
    const lldb_private::TimeValue &time,
    lldb::offset_t file_offset,
    lldb_private::DataExtractor &data
) :
    m_arch (arch),
    m_time (time),
    m_file_offset (file_offset),
    m_objects(),
    m_data (data)
{
}

ObjectContainerBSDArchive::Archive::~Archive ()
{
}

size_t
ObjectContainerBSDArchive::Archive::ParseObjects ()
{
    DataExtractor &data = m_data;
    std::string str;
    lldb::offset_t offset = 0;
    str.assign((const char *)data.GetData(&offset, SARMAG), SARMAG);
    if (str == ARMAG)
    {
        Object obj;
        do
        {
            offset = obj.Extract (data, offset);
            if (offset == LLDB_INVALID_OFFSET)
                break;
            size_t obj_idx = m_objects.size();
            m_objects.push_back(obj);
            // Insert all of the C strings out of order for now...
            m_object_name_to_index_map.Append (obj.ar_name.GetCString(), obj_idx);
            offset += obj.ar_file_size;
            obj.Clear();
        } while (data.ValidOffset(offset));

        // Now sort all of the object name pointers
        m_object_name_to_index_map.Sort ();
    }
    return m_objects.size();
}

ObjectContainerBSDArchive::Object *
ObjectContainerBSDArchive::Archive::FindObject (const ConstString &object_name, const TimeValue &object_mod_time)
{
    const ObjectNameToIndexMap::Entry *match = m_object_name_to_index_map.FindFirstValueForName (object_name.GetCString());
    if (match)
    {
        if (object_mod_time.IsValid())
        {
            const uint64_t object_date = object_mod_time.GetAsSecondsSinceJan1_1970();
            if (m_objects[match->value].ar_date == object_date)
                return &m_objects[match->value];
            const ObjectNameToIndexMap::Entry *next_match = m_object_name_to_index_map.FindNextValueForName (match);
            while (next_match)
            {
                if (m_objects[next_match->value].ar_date == object_date)
                    return &m_objects[next_match->value];
                next_match = m_object_name_to_index_map.FindNextValueForName (next_match);
            }
        }
        else
        {
            return &m_objects[match->value];
        }
    }
    return NULL;
}


ObjectContainerBSDArchive::Archive::shared_ptr
ObjectContainerBSDArchive::Archive::FindCachedArchive (const FileSpec &file, const ArchSpec &arch, const TimeValue &time, lldb::offset_t file_offset)
{
    Mutex::Locker locker(Archive::GetArchiveCacheMutex ());
    shared_ptr archive_sp;
    Archive::Map &archive_map = Archive::GetArchiveCache ();
    Archive::Map::iterator pos = archive_map.find (file);
    // Don't cache a value for "archive_map.end()" below since we might
    // delete an archive entry...
    while (pos != archive_map.end() && pos->first == file)
    {
        bool match = true;
        if (arch.IsValid() && pos->second->GetArchitecture().IsCompatibleMatch(arch) == false)
            match = false;
        else if (file_offset != LLDB_INVALID_OFFSET && pos->second->GetFileOffset() != file_offset)
            match = false;
        if (match)
        {
            if (pos->second->GetModificationTime() == time)
            {
                return pos->second;
            }
            else
            {
                // We have a file at the same path with the same architecture
                // whose modification time doesn't match. It doesn't make sense
                // for us to continue to use this BSD archive since we cache only
                // the object info which consists of file time info and also the
                // file offset and file size of any contianed objects. Since
                // this information is now out of date, we won't get the correct
                // information if we go and extract the file data, so we should
                // remove the old and outdated entry.
                archive_map.erase (pos);
                pos = archive_map.find (file);
                continue; // Continue to next iteration so we don't increment pos below...
            }
        }
        ++pos;
    }
    return archive_sp;
}

ObjectContainerBSDArchive::Archive::shared_ptr
ObjectContainerBSDArchive::Archive::ParseAndCacheArchiveForFile
(
    const FileSpec &file,
    const ArchSpec &arch,
    const TimeValue &time,
    lldb::offset_t file_offset,
    DataExtractor &data
)
{
    shared_ptr archive_sp(new Archive (arch, time, file_offset, data));
    if (archive_sp)
    {
        const size_t num_objects = archive_sp->ParseObjects ();
        if (num_objects > 0)
        {
            Mutex::Locker locker(Archive::GetArchiveCacheMutex ());
            Archive::GetArchiveCache().insert(std::make_pair(file, archive_sp));
        }
        else
        {
            archive_sp.reset();
        }
    }
    return archive_sp;
}

ObjectContainerBSDArchive::Archive::Map &
ObjectContainerBSDArchive::Archive::GetArchiveCache ()
{
    static Archive::Map g_archive_map;
    return g_archive_map;
}

Mutex &
ObjectContainerBSDArchive::Archive::GetArchiveCacheMutex ()
{
    static Mutex g_archive_map_mutex (Mutex::eMutexTypeRecursive);
    return g_archive_map_mutex;
}


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

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


lldb_private::ConstString
ObjectContainerBSDArchive::GetPluginNameStatic()
{
    static ConstString g_name("bsd-archive");
    return g_name;
}

const char *
ObjectContainerBSDArchive::GetPluginDescriptionStatic()
{
    return "BSD Archive object container reader.";
}


ObjectContainer *
ObjectContainerBSDArchive::CreateInstance
(
    const lldb::ModuleSP &module_sp,
    DataBufferSP& data_sp,
    lldb::offset_t data_offset,
    const FileSpec *file,
    lldb::offset_t file_offset,
    lldb::offset_t length)
{
    ConstString object_name (module_sp->GetObjectName());
    if (object_name)
    {
        if (data_sp)
        {
            // We have data, which means this is the first 512 bytes of the file
            // Check to see if the magic bytes match and if they do, read the entire
            // table of contents for the archive and cache it
            DataExtractor data;
            data.SetData (data_sp, data_offset, length);
            if (file && data_sp && ObjectContainerBSDArchive::MagicBytesMatch(data))
            {
                Timer scoped_timer (__PRETTY_FUNCTION__,
                                    "ObjectContainerBSDArchive::CreateInstance (module = %s, file = %p, file_offset = 0x%8.8" PRIx64 ", file_size = 0x%8.8" PRIx64 ")",
                                    module_sp->GetFileSpec().GetPath().c_str(),
                                    file, (uint64_t) file_offset, (uint64_t) length);

                // Map the entire .a file to be sure that we don't lose any data if the file
                // gets updated by a new build while this .a file is being used for debugging
                DataBufferSP archive_data_sp (file->MemoryMapFileContents(file_offset, length));
                lldb::offset_t archive_data_offset = 0;

                Archive::shared_ptr archive_sp (Archive::FindCachedArchive (*file,
                                                                            module_sp->GetArchitecture(),
                                                                            module_sp->GetModificationTime(),
                                                                            file_offset));
                std::unique_ptr<ObjectContainerBSDArchive> container_ap(new ObjectContainerBSDArchive (module_sp,
                                                                                                       archive_data_sp,
                                                                                                       archive_data_offset,
                                                                                                       file,
                                                                                                       file_offset,
                                                                                                       length));

                if (container_ap.get())
                {
                    if (archive_sp)
                    {
                        // We already have this archive in our cache, use it
                        container_ap->SetArchive (archive_sp);
                        return container_ap.release();
                    }
                    else if (container_ap->ParseHeader())
                        return container_ap.release();
                }
            }
        }
        else
        {
            // No data, just check for a cached archive
            Archive::shared_ptr archive_sp (Archive::FindCachedArchive (*file,
                                                                        module_sp->GetArchitecture(),
                                                                        module_sp->GetModificationTime(),
                                                                        file_offset));
            if (archive_sp)
            {
                std::unique_ptr<ObjectContainerBSDArchive> container_ap(new ObjectContainerBSDArchive (module_sp, data_sp, data_offset, file, file_offset, length));

                if (container_ap.get())
                {
                    // We already have this archive in our cache, use it
                    container_ap->SetArchive (archive_sp);
                    return container_ap.release();
                }
            }
        }
    }
    return NULL;
}


bool
ObjectContainerBSDArchive::MagicBytesMatch (const DataExtractor &data)
{
    uint32_t offset = 0;
    const char* armag = (const char* )data.PeekData (offset, sizeof(ar_hdr));
    if (armag && ::strncmp(armag, ARMAG, SARMAG) == 0)
    {
        armag += offsetof(struct ar_hdr, ar_fmag) + SARMAG;
        if (strncmp(armag, ARFMAG, 2) == 0)
            return true;
    }
    return false;
}

ObjectContainerBSDArchive::ObjectContainerBSDArchive
(
    const lldb::ModuleSP &module_sp,
    DataBufferSP& data_sp,
    lldb::offset_t data_offset,
    const lldb_private::FileSpec *file,
    lldb::offset_t file_offset,
    lldb::offset_t size
) :
    ObjectContainer (module_sp, file, file_offset, size, data_sp, data_offset),
    m_archive_sp ()
{
}
void
ObjectContainerBSDArchive::SetArchive (Archive::shared_ptr &archive_sp)
{
    m_archive_sp = archive_sp;
}


ObjectContainerBSDArchive::~ObjectContainerBSDArchive()
{
}

bool
ObjectContainerBSDArchive::ParseHeader ()
{
    if (m_archive_sp.get() == NULL)
    {
        if (m_data.GetByteSize() > 0)
        {
            ModuleSP module_sp (GetModule());
            if (module_sp)
            {
                m_archive_sp = Archive::ParseAndCacheArchiveForFile (m_file,
                                                                     module_sp->GetArchitecture(),
                                                                     module_sp->GetModificationTime(),
                                                                     m_offset,
                                                                     m_data);
            }
            // Clear the m_data that contains the entire archive
            // data and let our m_archive_sp hold onto the data.
            m_data.Clear();
        }
    }
    return m_archive_sp.get() != NULL;
}

void
ObjectContainerBSDArchive::Dump (Stream *s) const
{
    s->Printf("%p: ", this);
    s->Indent();
    const size_t num_archs = GetNumArchitectures();
    const size_t num_objects = GetNumObjects();
    s->Printf("ObjectContainerBSDArchive, num_archs = %lu, num_objects = %lu", num_archs, num_objects);
    uint32_t i;
    ArchSpec arch;
    s->IndentMore();
    for (i=0; i<num_archs; i++)
    {
        s->Indent();
        GetArchitectureAtIndex(i, arch);
        s->Printf("arch[%u] = %s\n", i, arch.GetArchitectureName());
    }
    for (i=0; i<num_objects; i++)
    {
        s->Indent();
        s->Printf("object[%u] = %s\n", i, GetObjectNameAtIndex (i));
    }
    s->IndentLess();
    s->EOL();
}

ObjectFileSP
ObjectContainerBSDArchive::GetObjectFile (const FileSpec *file)
{
    ModuleSP module_sp (GetModule());
    if (module_sp)
    {
        if (module_sp->GetObjectName() && m_archive_sp)
        {
            Object *object = m_archive_sp->FindObject (module_sp->GetObjectName(),
                                                       module_sp->GetObjectModificationTime());
            if (object)
            {
                lldb::offset_t data_offset = object->ar_file_offset;
                return ObjectFile::FindPlugin (module_sp,
                                               file,
                                               m_offset + object->ar_file_offset,
                                               object->ar_file_size,
                                               m_archive_sp->GetData().GetSharedDataBuffer(),
                                               data_offset);
            }
        }
    }
    return ObjectFileSP();
}


//------------------------------------------------------------------
// PluginInterface protocol
//------------------------------------------------------------------
lldb_private::ConstString
ObjectContainerBSDArchive::GetPluginName()
{
    return GetPluginNameStatic();
}

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


size_t
ObjectContainerBSDArchive::GetModuleSpecifications (const lldb_private::FileSpec& file,
                                                    lldb::DataBufferSP& data_sp,
                                                    lldb::offset_t data_offset,
                                                    lldb::offset_t file_offset,
                                                    lldb::offset_t file_size,
                                                    lldb_private::ModuleSpecList &specs)
{

    // We have data, which means this is the first 512 bytes of the file
    // Check to see if the magic bytes match and if they do, read the entire
    // table of contents for the archive and cache it
    DataExtractor data;
    data.SetData (data_sp, data_offset, data_sp->GetByteSize());
    if (file && data_sp && ObjectContainerBSDArchive::MagicBytesMatch(data))
    {
        const size_t initial_count = specs.GetSize();
        TimeValue file_mod_time = file.GetModificationTime();
        Archive::shared_ptr archive_sp (Archive::FindCachedArchive (file, ArchSpec(), file_mod_time, file_offset));
        bool set_archive_arch = false;
        if (!archive_sp)
        {
            set_archive_arch = true;
            DataBufferSP data_sp (file.MemoryMapFileContents(file_offset, file_size));
            data.SetData (data_sp, 0, data_sp->GetByteSize());
            archive_sp = Archive::ParseAndCacheArchiveForFile(file, ArchSpec(), file_mod_time, file_offset, data);
        }

        if (archive_sp)
        {
            const size_t num_objects = archive_sp->GetNumObjects();
            for (size_t idx = 0; idx < num_objects; ++idx)
            {
                const Object *object = archive_sp->GetObjectAtIndex (idx);
                if (object)
                {
                    const lldb::offset_t object_file_offset = file_offset + object->ar_file_offset;
                    if (object->ar_file_offset < file_size && file_size > object_file_offset)
                    {
                        if (ObjectFile::GetModuleSpecifications(file,
                                                                object_file_offset,
                                                                file_size - object_file_offset,
                                                                specs))
                        {
                            ModuleSpec &spec = specs.GetModuleSpecRefAtIndex (specs.GetSize() - 1);
                            TimeValue object_mod_time;
                            object_mod_time.OffsetWithSeconds(object->ar_date);
                            spec.GetObjectName () = object->ar_name;
                            spec.SetObjectOffset(object_file_offset);
                            spec.GetObjectModificationTime () = object_mod_time;
                        }
                    }
                }
            }
        }
        const size_t end_count = specs.GetSize();
        size_t num_specs_added = end_count - initial_count;
        if (set_archive_arch && num_specs_added > 0)
        {
            // The archive was created but we didn't have an architecture
            // so we need to set it
            for (size_t i=initial_count; i<end_count; ++ i)
            {
                ModuleSpec module_spec;
                if (specs.GetModuleSpecAtIndex(i, module_spec))
                {
                    if (module_spec.GetArchitecture().IsValid())
                    {
                        archive_sp->SetArchitecture (module_spec.GetArchitecture());
                        break;
                    }
                }
            }
        }
        return num_specs_added;
    }
    return 0;
}