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/*/@file
Qemu fw-cfg wrappers for hardware info parsing.
Provides an alternative to parse hardware information from a fw-cfg
file without relying on dynamic memory allocations.
Copyright 2021 - 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/DebugLib.h>
#include <Library/QemuFwCfgLib.h>
#include <Library/HardwareInfoLib.h>
/**
Update an optional pointer value if possible
@param[out] DataSize Pointer to variable to be updated
@param[in] Value Value to set the pointed variable to.
**/
STATIC
VOID
UpdateDataSize (
OUT UINTN *DataSize,
IN UINTN Value
)
{
if (DataSize == NULL) {
return;
}
*DataSize = Value;
}
EFI_STATUS
QemuFwCfgReadNextHardwareInfoByType (
IN HARDWARE_INFO_TYPE Type,
IN UINTN TypeSize,
IN UINTN TotalFileSize,
OUT VOID *Data,
OUT UINTN *DataSize OPTIONAL,
IN OUT UINTN *ReadIndex
)
{
HARDWARE_INFO_HEADER Header;
if ((Data == NULL) ||
(ReadIndex == NULL) ||
(TypeSize == 0) ||
(Type == HardwareInfoTypeUndefined) ||
(TotalFileSize == 0))
{
return EFI_INVALID_PARAMETER;
}
UpdateDataSize (DataSize, 0);
while (*ReadIndex < TotalFileSize) {
QemuFwCfgReadBytes (sizeof (Header), &Header);
*ReadIndex += sizeof (Header);
if ((Header.Size > MAX_UINTN) || (((UINT64)*ReadIndex + Header.Size) > TotalFileSize)) {
*ReadIndex = TotalFileSize;
return EFI_ABORTED;
}
if ((Header.Type.Value == Type) && (Header.Size <= TypeSize)) {
QemuFwCfgReadBytes ((UINTN)Header.Size, Data);
*ReadIndex += (UINTN)Header.Size;
UpdateDataSize (DataSize, (UINTN)Header.Size);
return EFI_SUCCESS;
}
//
// Skip the bytes corresponding to the next element as it is
// not of the expected type and/or size. The TotalFileSize
// and individual elements sizes should match so the size
// check is skipped.
//
QemuFwCfgSkipBytes ((UINTN)Header.Size);
*ReadIndex += (UINTN)Header.Size;
}
return EFI_END_OF_FILE;
}
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