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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/GUIDPartitionTable.h>
namespace Partition {
#define GPT_SIGNATURE2 0x54524150
#define GPT_SIGNATURE 0x20494645
struct [[gnu::packed]] GPTPartitionEntry {
u8 partition_guid[16];
u8 unique_guid[16];
u64 first_lba;
u64 last_lba;
u64 attributes;
char partition_name[72];
};
struct [[gnu::packed]] GUIDPartitionHeader {
u32 sig[2];
u32 revision;
u32 header_size;
u32 crc32_header;
u32 reserved;
u64 current_lba;
u64 backup_lba;
u64 first_usable_lba;
u64 last_usable_lba;
u64 disk_guid1[2];
u64 partition_array_start_lba;
u32 entries_count;
u32 partition_entry_size;
u32 crc32_entries_array;
};
ErrorOr<NonnullOwnPtr<GUIDPartitionTable>> GUIDPartitionTable::try_to_initialize(Kernel::StorageDevice const& device)
{
auto table = TRY(adopt_nonnull_own_or_enomem(new (nothrow) GUIDPartitionTable(device)));
if (!table->is_valid())
return Error::from_errno(EINVAL);
return table;
}
GUIDPartitionTable::GUIDPartitionTable(Kernel::StorageDevice const& device)
: MBRPartitionTable(device)
{
// FIXME: Handle OOM failure here.
m_cached_header = ByteBuffer::create_zeroed(m_device->block_size()).release_value_but_fixme_should_propagate_errors();
VERIFY(partitions_count() == 0);
if (!initialize())
m_valid = false;
}
GUIDPartitionHeader const& GUIDPartitionTable::header() const
{
return *(GUIDPartitionHeader const*)m_cached_header.data();
}
bool GUIDPartitionTable::initialize()
{
VERIFY(m_cached_header.data() != nullptr);
auto first_gpt_block = (m_device->block_size() == 512) ? 1 : 0;
auto buffer = UserOrKernelBuffer::for_kernel_buffer(m_cached_header.data());
if (!m_device->read_block(first_gpt_block, buffer)) {
return false;
}
dbgln_if(GPT_DEBUG, "GUIDPartitionTable: signature - {:#08x} {:#08x}", header().sig[1], header().sig[0]);
if (header().sig[0] != GPT_SIGNATURE && header().sig[1] != GPT_SIGNATURE2) {
dbgln("GUIDPartitionTable: bad signature {:#08x} {:#08x}", header().sig[1], header().sig[0]);
return false;
}
auto entries_buffer_result = ByteBuffer::create_zeroed(m_device->block_size());
if (entries_buffer_result.is_error()) {
dbgln("GUIPartitionTable: not enough memory for entries buffer");
return false;
}
auto entries_buffer = entries_buffer_result.release_value();
auto raw_entries_buffer = UserOrKernelBuffer::for_kernel_buffer(entries_buffer.data());
size_t raw_byte_index = header().partition_array_start_lba * m_device->block_size();
for (size_t entry_index = 0; entry_index < header().entries_count; entry_index++) {
if (!m_device->read_block((raw_byte_index / m_device->block_size()), raw_entries_buffer)) {
return false;
}
auto* entries = (GPTPartitionEntry const*)entries_buffer.data();
auto& entry = entries[entry_index % (m_device->block_size() / (size_t)header().partition_entry_size)];
Array<u8, 16> partition_type {};
partition_type.span().overwrite(0, entry.partition_guid, partition_type.size());
if (is_unused_entry(partition_type)) {
raw_byte_index += header().partition_entry_size;
continue;
}
Array<u8, 16> unique_guid {};
unique_guid.span().overwrite(0, entry.unique_guid, unique_guid.size());
dbgln("Detected GPT partition (entry={}), offset={}, limit={}", entry_index, entry.first_lba, entry.last_lba);
m_partitions.append({ entry.first_lba, entry.last_lba, partition_type, unique_guid, entry.attributes });
raw_byte_index += header().partition_entry_size;
}
return true;
}
bool GUIDPartitionTable::is_unused_entry(Array<u8, 16> partition_type) const
{
return all_of(partition_type, [](auto const octet) { return octet == 0; });
}
}
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