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/*
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
* 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/EBRPartitionTable.h>
#ifndef EBR_DEBUG
# define EBR_DEBUG
#endif
namespace Kernel {
EBRPartitionTable::EBRPartitionTable(NonnullRefPtr<BlockDevice> device)
: m_device(move(device))
{
}
EBRPartitionTable::~EBRPartitionTable()
{
}
const MBRPartitionHeader& EBRPartitionTable::header() const
{
return *reinterpret_cast<const MBRPartitionHeader*>(m_cached_mbr_header);
}
const EBRPartitionExtension& EBRPartitionTable::ebr_extension() const
{
return *reinterpret_cast<const EBRPartitionExtension*>(m_cached_ebr_header);
}
int EBRPartitionTable::index_of_ebr_container() const
{
for (int i = 0; i < 4; i++) {
if (header().entry[i].type == EBR_CHS_CONTAINER || header().entry[i].type == EBR_LBA_CONTAINER)
return i;
}
ASSERT_NOT_REACHED();
}
bool EBRPartitionTable::initialize()
{
if (!m_device->read_block(0, m_cached_mbr_header)) {
return false;
}
auto& header = this->header();
m_ebr_container_id = index_of_ebr_container() + 1;
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::initialize: MBR_signature=0x" << String::format("%x", header.mbr_signature);
#endif
if (header.mbr_signature != MBR_SIGNATURE) {
klog() << "EBRPartitionTable::initialize: bad MBR signature 0x" << String::format("%x", header.mbr_signature);
return false;
}
auto& ebr_entry = header.entry[m_ebr_container_id - 1];
if (!m_device->read_block(ebr_entry.offset, m_cached_ebr_header)) {
return false;
}
size_t index = 1;
while (index < 128) { // Unlikely to encounter a disk with 128 partitions in this configuration...
if (ebr_extension().next_chained_ebr_extension.offset == 0 && ebr_extension().next_chained_ebr_extension.type == 0) {
break;
}
index++;
if (!m_device->read_block(ebr_extension().next_chained_ebr_extension.offset, m_cached_ebr_header)) {
return false;
}
}
m_ebr_chained_extensions_count = index;
klog() << "EBRPartitionTable::initialize: Extended partitions count - " << m_ebr_chained_extensions_count;
return true;
}
RefPtr<DiskPartition> EBRPartitionTable::get_non_extended_partition(unsigned index)
{
auto& header = this->header();
auto& entry = header.entry[index - 1];
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: status=0x" << String::format("%x", entry.status) << " offset=0x" << String::format("%x", entry.offset);
#endif
if (entry.offset == 0x00) {
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: missing partition requested index=" << index;
#endif
return nullptr;
}
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: found partition index=" << index << " type=" << String::format("%x", entry.type);
#endif
return DiskPartition::create(m_device, entry.offset, (entry.offset + entry.length));
}
RefPtr<DiskPartition> EBRPartitionTable::get_extended_partition(unsigned index)
{
unsigned relative_index = index - m_ebr_container_id;
auto& header = this->header();
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: relative index " << relative_index;
#endif
auto& ebr_entry = header.entry[m_ebr_container_id - 1];
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: Extended partition, offset 0x" << String::format("%x", ebr_entry.offset) << ", type " << String::format("%x", ebr_entry.type);
#endif
if (!m_device->read_block(ebr_entry.offset, m_cached_ebr_header)) {
return nullptr;
}
size_t i = 0;
while (i < relative_index) {
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: logical partition, relative offset 0x" << String::format("%x", ebr_extension().entry.offset) << ", type " << String::format("%x", ebr_extension().entry.type);
klog() << "EBRPartitionTable::partition: next logical partition, relative offset 0x" << String::format("%x", ebr_extension().next_chained_ebr_extension.offset) << ", type " << String::format("%x", ebr_extension().next_chained_ebr_extension.type);
#endif
if (ebr_extension().next_chained_ebr_extension.offset == 0 && ebr_extension().next_chained_ebr_extension.type == 0) {
break;
}
i++;
if (!m_device->read_block(ebr_extension().next_chained_ebr_extension.offset, m_cached_ebr_header)) {
return nullptr;
}
}
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: status=" << String::format("%x", ebr_extension().entry.status) << " offset=" << String::format("%x", ebr_extension().entry.offset + ebr_entry.offset);
#endif
if (ebr_extension().entry.offset == 0x00) {
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: missing partition requested index=" << index;
#endif
return nullptr;
}
#ifdef EBR_DEBUG
klog() << "EBRPartitionTable::partition: found partition index=" << index << " type=" << String::format("%x", ebr_extension().entry.type);
#endif
return DiskPartition::create(m_device, ebr_extension().entry.offset + ebr_entry.offset, (ebr_extension().entry.offset + ebr_entry.offset + ebr_extension().entry.length));
}
bool EBRPartitionTable::index_is_extended_partition(unsigned index) const
{
return !(m_ebr_container_id > index || index > (m_ebr_container_id + m_ebr_chained_extensions_count));
}
RefPtr<DiskPartition> EBRPartitionTable::partition(unsigned index)
{
ASSERT(index >= 1 && index <= m_ebr_chained_extensions_count + 4);
auto& header = this->header();
if (header.mbr_signature != MBR_SIGNATURE) {
klog() << "EBRPartitionTable::initialize: bad MBR signature - not initalized? 0x" << String::format("%x", header.mbr_signature);
return nullptr;
}
if (index_is_extended_partition(index))
return get_extended_partition(index);
if (index > 4)
return get_non_extended_partition(index - m_ebr_chained_extensions_count);
return get_non_extended_partition(index);
}
}
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