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https://github.com/RGBCube/serenity
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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.
74 lines
2.7 KiB
C++
74 lines
2.7 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 <LibPartition/EBRPartitionTable.h>
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namespace Partition {
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ErrorOr<NonnullOwnPtr<EBRPartitionTable>> EBRPartitionTable::try_to_initialize(PartitionableDevice device)
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{
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auto table = TRY(adopt_nonnull_own_or_enomem(new (nothrow) EBRPartitionTable(move(device))));
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if (table->is_protective_mbr())
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return Error::from_errno(ENOTSUP);
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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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void EBRPartitionTable::search_extended_partition(MBRPartitionTable& checked_ebr, u64 current_block_offset, size_t limit)
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{
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if (limit == 0)
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return;
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// EBRs should not carry more than 2 partitions (because they need to form a linked list)
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VERIFY(checked_ebr.partitions_count() <= 2);
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// FIXME: We should not crash the Kernel or any apps when the EBR is malformed.
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auto checked_logical_partition = checked_ebr.partition(0);
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// If we are pointed to an invalid logical partition, something is seriously wrong.
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VERIFY(checked_logical_partition.has_value());
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m_partitions.append(checked_logical_partition.value().offset(current_block_offset));
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if (!checked_ebr.contains_ebr())
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return;
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current_block_offset += checked_ebr.partition(1).value().start_block();
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auto next_ebr = MBRPartitionTable::try_to_initialize(m_device.clone_unowned(), current_block_offset);
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if (!next_ebr)
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return;
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// FIXME: Should not rely on TCO here, since this might be called from inside the Kernel, where stack space isn't exactly free.
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search_extended_partition(*next_ebr, current_block_offset, (limit - 1));
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}
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EBRPartitionTable::EBRPartitionTable(PartitionableDevice device)
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: MBRPartitionTable(move(device))
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{
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if (!is_header_valid())
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return;
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m_valid = true;
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VERIFY(partitions_count() == 0);
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auto& header = this->header();
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for (size_t index = 0; index < 4; index++) {
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auto& entry = header.entry[index];
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// Start enumerating all logical partitions
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if (entry.type == 0xf) {
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auto checked_ebr = MBRPartitionTable::try_to_initialize(m_device.clone_unowned(), entry.offset);
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if (!checked_ebr)
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continue;
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// It's quite unlikely to see that amount of partitions, so stop at 128 partitions.
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search_extended_partition(*checked_ebr, entry.offset, 128);
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continue;
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}
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if (entry.offset == 0x00) {
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continue;
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}
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MUST(m_partitions.try_empend(entry.offset, (entry.offset + entry.length) - 1, entry.type));
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}
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}
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EBRPartitionTable::~EBRPartitionTable() = default;
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}
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