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The implemented cloning mechanism should be sound: - If a PartitionTable is passed a File with ShouldCloseFileDescriptor::Yes, then it will keep it alive until the PartitionTable is destroyed. - If a PartitionTable is passed a File with ShouldCloseFileDescriptor::No, then the caller has to ensure that the file descriptor remains alive. If the caller is EBRPartitionTable, the same consideration holds. If the caller is PartitionEditor::PartitionModel, this is satisfied by keeping an OwnPtr<Core::File> around which is the originally opened file. Therefore, we never leak any fds, and never access a Core::File or fd after destroying it.
124 lines
3.8 KiB
C++
124 lines
3.8 KiB
C++
/*
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* Copyright (c) 2020-2022, Liav A. <liavalb@hotmail.co.il>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Debug.h>
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#include <LibPartition/GUIDPartitionTable.h>
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namespace Partition {
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#define GPT_SIGNATURE2 0x54524150
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#define GPT_SIGNATURE 0x20494645
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struct [[gnu::packed]] GPTPartitionEntry {
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u8 partition_guid[16];
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u8 unique_guid[16];
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u64 first_lba;
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u64 last_lba;
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u64 attributes;
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char partition_name[72];
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};
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struct [[gnu::packed]] GUIDPartitionHeader {
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u32 sig[2];
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u32 revision;
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u32 header_size;
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u32 crc32_header;
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u32 reserved;
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u64 current_lba;
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u64 backup_lba;
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u64 first_usable_lba;
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u64 last_usable_lba;
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u64 disk_guid1[2];
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u64 partition_array_start_lba;
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u32 entries_count;
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u32 partition_entry_size;
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u32 crc32_entries_array;
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};
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ErrorOr<NonnullOwnPtr<GUIDPartitionTable>> GUIDPartitionTable::try_to_initialize(PartitionableDevice device)
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{
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auto table = TRY(adopt_nonnull_own_or_enomem(new (nothrow) GUIDPartitionTable(move(device))));
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if (!table->is_valid())
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return Error::from_errno(EINVAL);
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return table;
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}
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GUIDPartitionTable::GUIDPartitionTable(PartitionableDevice device)
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: MBRPartitionTable(move(device))
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{
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// FIXME: Handle OOM failure here.
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m_cached_header = ByteBuffer::create_zeroed(block_size()).release_value_but_fixme_should_propagate_errors();
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VERIFY(partitions_count() == 0);
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if (!initialize())
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m_valid = false;
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}
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GUIDPartitionHeader const& GUIDPartitionTable::header() const
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{
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return *(GUIDPartitionHeader const*)m_cached_header.data();
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}
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bool GUIDPartitionTable::initialize()
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{
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VERIFY(m_cached_header.data() != nullptr);
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auto first_gpt_block = (block_size() == 512) ? 1 : 0;
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auto maybe_error = m_device.read_block(first_gpt_block, m_cached_header.bytes());
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if (maybe_error.is_error())
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return false;
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dbgln_if(GPT_DEBUG, "GUIDPartitionTable: signature - {:#08x} {:#08x}", header().sig[1], header().sig[0]);
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if (header().sig[0] != GPT_SIGNATURE && header().sig[1] != GPT_SIGNATURE2) {
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dbgln("GUIDPartitionTable: bad signature {:#08x} {:#08x}", header().sig[1], header().sig[0]);
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return false;
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}
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auto entries_buffer_result = ByteBuffer::create_zeroed(block_size());
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if (entries_buffer_result.is_error()) {
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dbgln("GUIDPartitionTable: not enough memory for entries buffer");
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return false;
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}
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auto entries_buffer = entries_buffer_result.release_value();
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size_t raw_byte_index = header().partition_array_start_lba * block_size();
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for (size_t entry_index = 0; entry_index < header().entries_count; entry_index++) {
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maybe_error = m_device.read_block(raw_byte_index / block_size(), entries_buffer.bytes());
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if (maybe_error.is_error())
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return false;
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auto* entries = (GPTPartitionEntry const*)entries_buffer.data();
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auto& entry = entries[entry_index % (block_size() / header().partition_entry_size)];
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Array<u8, 16> partition_type {};
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partition_type.span().overwrite(0, entry.partition_guid, partition_type.size());
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if (is_unused_entry(partition_type)) {
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raw_byte_index += header().partition_entry_size;
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continue;
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}
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Array<u8, 16> unique_guid {};
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unique_guid.span().overwrite(0, entry.unique_guid, unique_guid.size());
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dbgln("Detected GPT partition (entry={}), offset={}, limit={}", entry_index, entry.first_lba, entry.last_lba);
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m_partitions.append({ entry.first_lba, entry.last_lba, partition_type, unique_guid, entry.attributes });
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raw_byte_index += header().partition_entry_size;
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}
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return true;
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}
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bool GUIDPartitionTable::is_unused_entry(Array<u8, 16> partition_type) const
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{
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return all_of(partition_type, [](auto const octet) { return octet == 0; });
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}
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}
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