jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2020-2022, Liav A. <liavalb@hotmail.co.il>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <LibPartition/EBRPartitionTable.h>
8
9#ifndef KERNEL
10# include <LibCore/DeprecatedFile.h>
11#endif
12
13namespace Partition {
14
15#ifdef KERNEL
16ErrorOr<NonnullOwnPtr<EBRPartitionTable>> EBRPartitionTable::try_to_initialize(Kernel::StorageDevice& device)
17{
18 auto table = TRY(adopt_nonnull_own_or_enomem(new (nothrow) EBRPartitionTable(device)));
19#else
20ErrorOr<NonnullOwnPtr<EBRPartitionTable>> EBRPartitionTable::try_to_initialize(NonnullRefPtr<Core::DeprecatedFile> device_file)
21{
22 auto table = TRY(adopt_nonnull_own_or_enomem(new (nothrow) EBRPartitionTable(move(device_file))));
23#endif
24 if (table->is_protective_mbr())
25 return Error::from_errno(ENOTSUP);
26 if (!table->is_valid())
27 return Error::from_errno(EINVAL);
28 return table;
29}
30
31#ifdef KERNEL
32void EBRPartitionTable::search_extended_partition(Kernel::StorageDevice& device, MBRPartitionTable& checked_ebr, u64 current_block_offset, size_t limit)
33#else
34void EBRPartitionTable::search_extended_partition(NonnullRefPtr<Core::DeprecatedFile> device, MBRPartitionTable& checked_ebr, u64 current_block_offset, size_t limit)
35#endif
36{
37 if (limit == 0)
38 return;
39 // EBRs should not carry more than 2 partitions (because they need to form a linked list)
40 VERIFY(checked_ebr.partitions_count() <= 2);
41 auto checked_logical_partition = checked_ebr.partition(0);
42
43 // If we are pointed to an invalid logical partition, something is seriously wrong.
44 VERIFY(checked_logical_partition.has_value());
45 m_partitions.append(checked_logical_partition.value().offset(current_block_offset));
46 if (!checked_ebr.contains_ebr())
47 return;
48 current_block_offset += checked_ebr.partition(1).value().start_block();
49 auto next_ebr = MBRPartitionTable::try_to_initialize(device, current_block_offset);
50 if (!next_ebr)
51 return;
52 search_extended_partition(device, *next_ebr, current_block_offset, (limit - 1));
53}
54
55#ifdef KERNEL
56EBRPartitionTable::EBRPartitionTable(Kernel::StorageDevice& device)
57#else
58EBRPartitionTable::EBRPartitionTable(NonnullRefPtr<Core::DeprecatedFile> device)
59#endif
60 : MBRPartitionTable(device)
61{
62 if (!is_header_valid())
63 return;
64 m_valid = true;
65
66 VERIFY(partitions_count() == 0);
67
68 auto& header = this->header();
69 for (size_t index = 0; index < 4; index++) {
70 auto& entry = header.entry[index];
71 // Start enumerating all logical partitions
72 if (entry.type == 0xf) {
73 auto checked_ebr = MBRPartitionTable::try_to_initialize(device, entry.offset);
74 if (!checked_ebr)
75 continue;
76 // It's quite unlikely to see that amount of partitions, so stop at 128 partitions.
77 search_extended_partition(device, *checked_ebr, entry.offset, 128);
78 continue;
79 }
80
81 if (entry.offset == 0x00) {
82 continue;
83 }
84 MUST(m_partitions.try_empend(entry.offset, (entry.offset + entry.length) - 1, entry.type));
85 }
86}
87
88EBRPartitionTable::~EBRPartitionTable() = default;
89
90}