124 lines
3.5 KiB
C
124 lines
3.5 KiB
C
/** @file
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Disk utilities
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Copyright (c) 2021 Pedro Falcato All rights reserved.
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include "Ext4Dxe.h"
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/**
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Reads from the partition's disk using the DISK_IO protocol.
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@param[in] Partition Pointer to the opened ext4 partition.
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@param[out] Buffer Pointer to a destination buffer.
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@param[in] Length Length of the destination buffer.
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@param[in] Offset Offset, in bytes, of the location to read.
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@return Success status of the disk read.
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**/
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EFI_STATUS
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Ext4ReadDiskIo (
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IN EXT4_PARTITION *Partition,
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OUT VOID *Buffer,
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IN UINTN Length,
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IN UINT64 Offset
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)
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{
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return EXT4_DISK_IO (Partition)->ReadDisk (
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EXT4_DISK_IO (Partition),
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EXT4_MEDIA_ID (Partition),
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Offset,
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Length,
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Buffer
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);
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}
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/**
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Reads blocks from the partition's disk using the DISK_IO protocol.
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@param[in] Partition Pointer to the opened ext4 partition.
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@param[out] Buffer Pointer to a destination buffer.
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@param[in] NumberBlocks Length of the read, in filesystem blocks.
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@param[in] BlockNumber Starting block number.
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@return Success status of the read.
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**/
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EFI_STATUS
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Ext4ReadBlocks (
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IN EXT4_PARTITION *Partition,
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OUT VOID *Buffer,
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IN UINTN NumberBlocks,
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IN EXT4_BLOCK_NR BlockNumber
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)
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{
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UINT64 Offset;
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UINTN Length;
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ASSERT (NumberBlocks != 0);
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ASSERT (BlockNumber != EXT4_BLOCK_FILE_HOLE);
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Offset = MultU64x32 (BlockNumber, Partition->BlockSize);
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Length = NumberBlocks * Partition->BlockSize;
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// Check for overflow on the block -> byte conversions.
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// Partition->BlockSize is never 0, so we don't need to check for that.
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if (DivU64x64Remainder (Offset, BlockNumber, NULL) != Partition->BlockSize) {
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return EFI_INVALID_PARAMETER;
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}
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if (Length / NumberBlocks != Partition->BlockSize) {
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return EFI_INVALID_PARAMETER;
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}
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return Ext4ReadDiskIo (Partition, Buffer, Length, Offset);
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}
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/**
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Allocates a buffer and reads blocks from the partition's disk using the DISK_IO protocol.
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This function is deprecated and will be removed in the future.
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@param[in] Partition Pointer to the opened ext4 partition.
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@param[in] NumberBlocks Length of the read, in filesystem blocks.
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@param[in] BlockNumber Starting block number.
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@return Buffer allocated by AllocatePool, or NULL if some part of the process
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failed.
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**/
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VOID *
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Ext4AllocAndReadBlocks (
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IN EXT4_PARTITION *Partition,
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IN UINTN NumberBlocks,
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IN EXT4_BLOCK_NR BlockNumber
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)
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{
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VOID *Buf;
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UINTN Length;
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// Check that number of blocks isn't empty, because
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// this is incorrect condition for opened partition,
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// so we just early-exit
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if ((NumberBlocks == 0) || (BlockNumber == EXT4_BLOCK_FILE_HOLE)) {
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return NULL;
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}
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Length = NumberBlocks * Partition->BlockSize;
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// Check for integer overflow
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if (Length / NumberBlocks != Partition->BlockSize) {
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return NULL;
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}
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Buf = AllocatePool (Length);
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if (Buf == NULL) {
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return NULL;
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}
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if (Ext4ReadBlocks (Partition, Buf, NumberBlocks, BlockNumber) != EFI_SUCCESS) {
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FreePool (Buf);
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return NULL;
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}
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return Buf;
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}
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