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/*
* Copyright (c) 2020-2022, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Debug.h>
#include <LibPartition/MBRPartitionTable.h>
namespace Partition {
#define MBR_SIGNATURE 0xaa55
#define MBR_PROTECTIVE 0xEE
#define EBR_CHS_CONTAINER 0x05
#define EBR_LBA_CONTAINER 0x0F
#ifdef KERNEL
ErrorOr<NonnullOwnPtr<MBRPartitionTable>> MBRPartitionTable::try_to_initialize(Kernel::StorageDevice const& device)
{
auto table = TRY(adopt_nonnull_own_or_enomem(new (nothrow) MBRPartitionTable(device)));
#else
ErrorOr<NonnullOwnPtr<MBRPartitionTable>> MBRPartitionTable::try_to_initialize(NonnullRefPtr<Core::File> device_file)
{
auto table = TRY(adopt_nonnull_own_or_enomem(new (nothrow) MBRPartitionTable(move(device_file))));
#endif
if (table->contains_ebr())
return Error::from_errno(ENOTSUP);
if (table->is_protective_mbr())
return Error::from_errno(ENOTSUP);
if (!table->is_valid())
return Error::from_errno(EINVAL);
return table;
}
#ifdef KERNEL
OwnPtr<MBRPartitionTable> MBRPartitionTable::try_to_initialize(Kernel::StorageDevice const& device, u32 start_lba)
{
auto table = adopt_nonnull_own_or_enomem(new (nothrow) MBRPartitionTable(device, start_lba)).release_value_but_fixme_should_propagate_errors();
#else
OwnPtr<MBRPartitionTable> MBRPartitionTable::try_to_initialize(NonnullRefPtr<Core::File> device_file, u32 start_lba)
{
auto table = adopt_nonnull_own_or_enomem(new (nothrow) MBRPartitionTable(move(device_file), start_lba)).release_value_but_fixme_should_propagate_errors();
#endif
if (!table->is_valid())
return {};
return table;
}
bool MBRPartitionTable::read_boot_record()
{
#ifdef KERNEL
auto buffer = UserOrKernelBuffer::for_kernel_buffer(m_cached_header.data());
if (!m_device->read_block(m_start_lba, buffer))
return false;
#else
m_device_file->seek(m_start_lba * m_block_size);
if (m_device_file->read(m_cached_header.data(), m_cached_header.size()) != 512)
return false;
#endif
m_header_valid = true;
return m_header_valid;
}
#ifdef KERNEL
MBRPartitionTable::MBRPartitionTable(Kernel::StorageDevice const& device, u32 start_lba)
: PartitionTable(device)
#else
MBRPartitionTable::MBRPartitionTable(NonnullRefPtr<Core::File> device_file, u32 start_lba)
: PartitionTable(move(device_file))
#endif
, m_start_lba(start_lba)
, m_cached_header(ByteBuffer::create_zeroed(m_block_size).release_value_but_fixme_should_propagate_errors()) // FIXME: Do something sensible if this fails because of OOM.
{
if (!read_boot_record() || !initialize())
return;
m_header_valid = true;
auto& header = this->header();
for (size_t index = 0; index < 4; index++) {
auto& entry = header.entry[index];
if (entry.offset == 0x00) {
continue;
}
MUST(m_partitions.try_empend(entry.offset, (entry.offset + entry.length) - 1, entry.type));
}
m_valid = true;
}
#ifdef KERNEL
MBRPartitionTable::MBRPartitionTable(Kernel::StorageDevice const& device)
: PartitionTable(device)
#else
MBRPartitionTable::MBRPartitionTable(NonnullRefPtr<Core::File> device_file)
: PartitionTable(move(device_file))
#endif
, m_start_lba(0)
, m_cached_header(ByteBuffer::create_zeroed(m_block_size).release_value_but_fixme_should_propagate_errors()) // FIXME: Do something sensible if this fails because of OOM.
{
if (!read_boot_record() || contains_ebr() || is_protective_mbr() || !initialize())
return;
auto& header = this->header();
for (size_t index = 0; index < 4; index++) {
auto& entry = header.entry[index];
if (entry.offset == 0x00) {
continue;
}
MUST(m_partitions.try_empend(entry.offset, (entry.offset + entry.length) - 1, entry.type));
}
m_valid = true;
}
MBRPartitionTable::~MBRPartitionTable() = default;
MBRPartitionTable::Header const& MBRPartitionTable::header() const
{
return *(MBRPartitionTable::Header const*)m_cached_header.data();
}
bool MBRPartitionTable::initialize()
{
auto& header = this->header();
dbgln_if(MBR_DEBUG, "Master Boot Record: mbr_signature={:#08x}", header.mbr_signature);
if (header.mbr_signature != MBR_SIGNATURE) {
dbgln("Master Boot Record: invalid 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;
}
}
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