ladybird/Kernel/Devices/MBRPartitionTable.cpp
2020-02-16 01:27:42 +01:00

113 lines
3.4 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>
#define MBR_DEBUG
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()
{
if (!m_device->read_block(0, m_cached_header)) {
return false;
}
auto& header = this->header();
#ifdef MBR_DEBUG
kprintf("MBRPartitionTable::initialize: mbr_signature=%#x\n", header.mbr_signature);
#endif
if (header.mbr_signature != MBR_SIGNATURE) {
kprintf("MBRPartitionTable::initialize: bad mbr signature %#x\n", 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) {
kprintf("MBRPartitionTable::initialize: bad mbr signature - not initalized? %#x\n", header.mbr_signature);
return nullptr;
}
#ifdef MBR_DEBUG
kprintf("MBRPartitionTable::partition: status=%#x offset=%#x\n", entry.status, entry.offset);
#endif
if (entry.offset == 0x00) {
#ifdef MBR_DEBUG
kprintf("MBRPartitionTable::partition: missing partition requested index=%d\n", index);
#endif
return nullptr;
}
#ifdef MBR_DEBUG
kprintf("MBRPartitionTable::partition: found partition index=%d type=%x\n", index, entry.type);
#endif
return DiskPartition::create(m_device, entry.offset, (entry.offset + entry.length));
}
}