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The partitioning code was very outdated, and required a full refactor. The new subsystem removes duplicated code and uses more AK containers. The most important change is that all implementations of the PartitionTable class conform to one interface, which made it possible to remove unnecessary code in the EBRPartitionTable class. Finding partitions is now done in the StorageManagement singleton, instead of doing so in init.cpp. Also, now we don't try to find partitions on demand - the kernel will try to detect if a StorageDevice is partitioned, and if so, will check what is the partition table, which could be MBR, GUID or EBR. Then, it will create DiskPartitionMetadata object for each partition that is available in the partition table. This object will be used by the partition enumeration code to create a DiskPartition with the correct minor number.
101 lines
3.9 KiB
C++
101 lines
3.9 KiB
C++
/*
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* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/ByteBuffer.h>
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#include <Kernel/Storage/Partition/EBRPartitionTable.h>
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#ifndef EBR_DEBUG
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# define EBR_DEBUG
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#endif
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namespace Kernel {
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Result<NonnullOwnPtr<EBRPartitionTable>, PartitionTable::Error> EBRPartitionTable::try_to_initialize(const StorageDevice& device)
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{
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auto table = make<EBRPartitionTable>(device);
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if (table->is_protective_mbr())
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return { PartitionTable::Error::MBRProtective };
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if (!table->is_valid())
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return { PartitionTable::Error::Invalid };
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return table;
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}
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void EBRPartitionTable::search_extended_partition(const StorageDevice& device, 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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ASSERT(checked_ebr.partitions_count() <= 2);
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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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ASSERT(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(device, current_block_offset);
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if (!next_ebr)
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return;
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search_extended_partition(device, *next_ebr, current_block_offset, (limit - 1));
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}
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EBRPartitionTable::EBRPartitionTable(const StorageDevice& device)
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: MBRPartitionTable(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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ASSERT(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(device, 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(device, *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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auto partition_type = ByteBuffer::create_zeroed(sizeof(u8));
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partition_type.data()[0] = entry.type;
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m_partitions.append(DiskPartitionMetadata({ entry.offset, (entry.offset + entry.length), partition_type }));
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}
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}
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EBRPartitionTable::~EBRPartitionTable()
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{
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}
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}
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