1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
/** @file
Disk utilities
Copyright (c) 2021 Pedro Falcato All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "Ext4Dxe.h"
/**
Reads from the partition's disk using the DISK_IO protocol.
@param[in] Partition Pointer to the opened ext4 partition.
@param[out] Buffer Pointer to a destination buffer.
@param[in] Length Length of the destination buffer.
@param[in] Offset Offset, in bytes, of the location to read.
@return Success status of the disk read.
**/
EFI_STATUS
Ext4ReadDiskIo (
IN EXT4_PARTITION *Partition,
OUT VOID *Buffer,
IN UINTN Length,
IN UINT64 Offset
)
{
return EXT4_DISK_IO (Partition)->ReadDisk (
EXT4_DISK_IO (Partition),
EXT4_MEDIA_ID (Partition),
Offset,
Length,
Buffer
);
}
/**
Reads blocks from the partition's disk using the DISK_IO protocol.
@param[in] Partition Pointer to the opened ext4 partition.
@param[out] Buffer Pointer to a destination buffer.
@param[in] NumberBlocks Length of the read, in filesystem blocks.
@param[in] BlockNumber Starting block number.
@return Success status of the read.
**/
EFI_STATUS
Ext4ReadBlocks (
IN EXT4_PARTITION *Partition,
OUT VOID *Buffer,
IN UINTN NumberBlocks,
IN EXT4_BLOCK_NR BlockNumber
)
{
UINT64 Offset;
UINTN Length;
ASSERT (NumberBlocks != 0);
ASSERT (BlockNumber != EXT4_BLOCK_FILE_HOLE);
Offset = MultU64x32 (BlockNumber, Partition->BlockSize);
Length = NumberBlocks * Partition->BlockSize;
// Check for overflow on the block -> byte conversions.
// Partition->BlockSize is never 0, so we don't need to check for that.
if (DivU64x64Remainder (Offset, BlockNumber, NULL) != Partition->BlockSize) {
return EFI_INVALID_PARAMETER;
}
if (Length / NumberBlocks != Partition->BlockSize) {
return EFI_INVALID_PARAMETER;
}
return Ext4ReadDiskIo (Partition, Buffer, Length, Offset);
}
/**
Allocates a buffer and reads blocks from the partition's disk using the DISK_IO protocol.
This function is deprecated and will be removed in the future.
@param[in] Partition Pointer to the opened ext4 partition.
@param[in] NumberBlocks Length of the read, in filesystem blocks.
@param[in] BlockNumber Starting block number.
@return Buffer allocated by AllocatePool, or NULL if some part of the process
failed.
**/
VOID *
Ext4AllocAndReadBlocks (
IN EXT4_PARTITION *Partition,
IN UINTN NumberBlocks,
IN EXT4_BLOCK_NR BlockNumber
)
{
VOID *Buf;
UINTN Length;
// Check that number of blocks isn't empty, because
// this is incorrect condition for opened partition,
// so we just early-exit
if ((NumberBlocks == 0) || (BlockNumber == EXT4_BLOCK_FILE_HOLE)) {
return NULL;
}
Length = NumberBlocks * Partition->BlockSize;
// Check for integer overflow
if (Length / NumberBlocks != Partition->BlockSize) {
return NULL;
}
Buf = AllocatePool (Length);
if (Buf == NULL) {
return NULL;
}
if (Ext4ReadBlocks (Partition, Buf, NumberBlocks, BlockNumber) != EFI_SUCCESS) {
FreePool (Buf);
return NULL;
}
return Buf;
}
|
