ladybird/Kernel/Devices/MBRPartitionTable.cpp
2020-10-03 12:36:49 +02:00

116 lines
3.7 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/ByteBuffer.h>
#include <Kernel/Devices/MBRPartitionTable.h>
#ifndef MBR_DEBUG
# define MBR_DEBUG
#endif
namespace Kernel {
MBRPartitionTable::MBRPartitionTable(NonnullRefPtr<BlockDevice> device)
: m_device(move(device))
{
}
MBRPartitionTable::~MBRPartitionTable()
{
}
const MBRPartitionHeader& MBRPartitionTable::header() const
{
return *reinterpret_cast<const MBRPartitionHeader*>(m_cached_header);
}
bool MBRPartitionTable::initialize()
{
auto header_buffer = UserOrKernelBuffer::for_kernel_buffer(m_cached_header);
if (!m_device->read_block(0, header_buffer)) {
return false;
}
auto& header = this->header();
#ifdef MBR_DEBUG
klog() << "MBRPartitionTable::initialize: mbr_signature=0x" << String::format("%x", header.mbr_signature);
#endif
if (header.mbr_signature != MBR_SIGNATURE) {
klog() << "MBRPartitionTable::initialize: bad mbr signature 0x" << String::format("%x", header.mbr_signature);
return false;
}
return true;
}
bool MBRPartitionTable::contains_ebr() const
{
for (int i = 0; i < 4; i++) {
if (header().entry[i].type == EBR_CHS_CONTAINER || header().entry[i].type == EBR_LBA_CONTAINER)
return true;
}
return false;
}
bool MBRPartitionTable::is_protective_mbr() const
{
return header().entry[0].type == MBR_PROTECTIVE;
}
RefPtr<DiskPartition> MBRPartitionTable::partition(unsigned index)
{
ASSERT(index >= 1 && index <= 4);
auto& header = this->header();
auto& entry = header.entry[index - 1];
if (header.mbr_signature != MBR_SIGNATURE) {
klog() << "MBRPartitionTable::initialize: bad mbr signature - not initialized? 0x" << String::format("%x", header.mbr_signature);
return nullptr;
}
#ifdef MBR_DEBUG
klog() << "MBRPartitionTable::partition: status=0x" << String::format("%x", entry.status) << " offset=0x" << String::format("%x", entry.offset);
#endif
if (entry.offset == 0x00) {
#ifdef MBR_DEBUG
klog() << "MBRPartitionTable::partition: missing partition requested index=" << index;
#endif
return nullptr;
}
#ifdef MBR_DEBUG
klog() << "MBRPartitionTable::partition: found partition index=" << index << " type=" << String::format("%x", entry.type);
#endif
return DiskPartition::create(m_device, entry.offset, (entry.offset + entry.length));
}
}