5094454579
This library provides an interface where variables can be saved and restored using a file in a file system accessible to the firmware. It is expected that a platform BDS library will use this library. The platform BDS implementation can decide which devices to connect and then to attempt to use for saving and restoring NV variables. git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9272 6f19259b-4bc3-4df7-8a09-765794883524
346 lines
8.1 KiB
C
346 lines
8.1 KiB
C
/** @file
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File System Access
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Copyright (c) 2004 - 2009, Intel Corporation. <BR>
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "NvVarsFileLib.h"
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#include <Library/BaseMemoryLib.h>
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#include <Library/DebugLib.h>
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#include <Library/MemoryAllocationLib.h>
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#include <Library/UefiRuntimeServicesTableLib.h>
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/**
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Writes the variable into the file so it can be restored from
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the file on future boots of the system.
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@param[in] File - The file to write to
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@param[in] Name - Variable name string
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@param[in] NameSize - Size of Name in bytes
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@param[in] Guid - GUID of variable
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@param[in] Attributes - Attributes of variable
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@param[in] Data - Buffer containing Data for variable
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@param[in] DataSize - Size of Data in bytes
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@return EFI_STATUS based on the success or failure of the operation
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**/
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EFI_STATUS
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PackVariableIntoFile (
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IN EFI_FILE_HANDLE File,
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IN CHAR16 *Name,
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IN UINT32 NameSize,
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IN EFI_GUID *Guid,
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IN UINT32 Attributes,
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IN VOID *Data,
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IN UINT32 DataSize
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)
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{
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EFI_STATUS Status;
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UINTN WriteSize;
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WriteSize = sizeof (NameSize);
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Status = FileHandleWrite (File, &WriteSize, &NameSize);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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WriteSize = NameSize;
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Status = FileHandleWrite (File, &WriteSize, (VOID*) Name);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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WriteSize = sizeof (*Guid);
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Status = FileHandleWrite (File, &WriteSize, (VOID*) Guid);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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WriteSize = sizeof (Attributes);
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Status = FileHandleWrite (File, &WriteSize, &Attributes);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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WriteSize = sizeof (DataSize);
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Status = FileHandleWrite (File, &WriteSize, &DataSize);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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WriteSize = DataSize;
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Status = FileHandleWrite (File, &WriteSize, Data);
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return Status;
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}
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/**
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Unpacks the next variable from the NvVars file data
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@param[in] Buffer - Buffer pointing to the next variable instance
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On subsequent calls, the pointer should be incremented
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by the returned SizeUsed value.
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@param[in] MaxSize - Max allowable size for the variable data
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On subsequent calls, this should be decremented
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by the returned SizeUsed value.
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@param[out] Name - Variable name string (address in Buffer)
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@param[out] NameSize - Size of Name in bytes
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@param[out] Guid - GUID of variable (address in Buffer)
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@param[out] Attributes - Attributes of variable
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@param[out] Data - Buffer containing Data for variable (address in Buffer)
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@param[out] DataSize - Size of Data in bytes
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@param[out] SizeUsed - Total size used for this variable instance in Buffer
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@return EFI_STATUS based on the success or failure of the operation
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**/
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EFI_STATUS
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UnpackVariableFromBuffer (
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IN VOID *Buffer,
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IN UINTN MaxSize,
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OUT CHAR16 **Name,
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OUT UINT32 *NameSize,
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OUT EFI_GUID **Guid,
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OUT UINT32 *Attributes,
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OUT UINT32 *DataSize,
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OUT VOID **Data,
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OUT UINTN *SizeUsed
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)
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{
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UINT8 *BytePtr;
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UINTN Offset;
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BytePtr = (UINT8*)Buffer;
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Offset = 0;
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*NameSize = *(UINT32*) (BytePtr + Offset);
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Offset = Offset + sizeof (UINT32);
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if (Offset > MaxSize) {
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return EFI_INVALID_PARAMETER;
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}
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*Name = (CHAR16*) (BytePtr + Offset);
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Offset = Offset + *(UINT32*)BytePtr;
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if (Offset > MaxSize) {
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return EFI_INVALID_PARAMETER;
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}
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*Guid = (EFI_GUID*) (BytePtr + Offset);
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Offset = Offset + sizeof (EFI_GUID);
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if (Offset > MaxSize) {
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return EFI_INVALID_PARAMETER;
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}
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*Attributes = *(UINT32*) (BytePtr + Offset);
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Offset = Offset + sizeof (UINT32);
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if (Offset > MaxSize) {
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return EFI_INVALID_PARAMETER;
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}
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*DataSize = *(UINT32*) (BytePtr + Offset);
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Offset = Offset + sizeof (UINT32);
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if (Offset > MaxSize) {
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return EFI_INVALID_PARAMETER;
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}
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*Data = (VOID*) (BytePtr + Offset);
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Offset = Offset + *DataSize;
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if (Offset > MaxSize) {
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return EFI_INVALID_PARAMETER;
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}
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*SizeUsed = Offset;
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return EFI_SUCCESS;
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}
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/**
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Examines the NvVars file contents, and updates variables based on it.
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@param[in] Buffer - Buffer with NvVars data
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@param[in] MaxSize - Size of Buffer in bytes
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@param[in] DryRun - If TRUE, then no variable modifications should be made
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(If TRUE, the Buffer is still parsed for validity.)
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@return EFI_STATUS based on the success or failure of the operation
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**/
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EFI_STATUS
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UnpackVariablesFromBuffer (
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IN VOID *Buffer,
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IN UINTN MaxSize,
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IN BOOLEAN DryRun
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)
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{
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EFI_STATUS Status;
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UINTN Count;
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UINTN TotalSizeUsed;
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UINTN SizeUsed;
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CHAR16 *Name;
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UINT32 NameSize;
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CHAR16 *AlignedName;
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UINT32 AlignedNameMaxSize;
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EFI_GUID *Guid;
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UINT32 Attributes;
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UINT32 DataSize;
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VOID *Data;
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AlignedName = NULL;
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AlignedNameMaxSize = 0;
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for (
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Status = EFI_SUCCESS, Count = 0, TotalSizeUsed = 0;
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!EFI_ERROR (Status) && (TotalSizeUsed < MaxSize);
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) {
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Status = UnpackVariableFromBuffer (
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(VOID*) ((UINT8*) Buffer + TotalSizeUsed),
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(MaxSize - TotalSizeUsed),
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&Name,
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&NameSize,
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&Guid,
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&Attributes,
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&DataSize,
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&Data,
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&SizeUsed
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);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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//
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// We copy the name to a separately allocated buffer,
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// to be sure it is 16-bit aligned.
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//
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if (NameSize > AlignedNameMaxSize) {
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if (AlignedName != NULL) {
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FreePool (AlignedName);
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}
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AlignedName = AllocatePool (NameSize);
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}
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if (AlignedName == NULL) {
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return EFI_OUT_OF_RESOURCES;
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}
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CopyMem (AlignedName, Name, NameSize);
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DEBUG ((
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EFI_D_INFO,
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"Unpacked variable %g:%s\n",
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Guid,
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AlignedName
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));
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TotalSizeUsed = TotalSizeUsed + SizeUsed;
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DEBUG ((
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EFI_D_INFO,
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"TotalSizeUsed(%d); MaxSize(%d)\n",
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TotalSizeUsed,
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MaxSize
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));
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if (!DryRun) {
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//
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// Set the variable contents
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//
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gRT->SetVariable (
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AlignedName,
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Guid,
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Attributes,
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DataSize,
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Data
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);
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Count++;
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DEBUG ((
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EFI_D_INFO,
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"Restored variable %g:%s\n",
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Guid,
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AlignedName
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));
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}
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}
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if (AlignedName != NULL) {
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FreePool (AlignedName);
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}
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//
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// Make sure the entire buffer was used, or else return an error
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//
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if (TotalSizeUsed != MaxSize) {
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DEBUG ((
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EFI_D_INFO,
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"TotalSizeUsed(%d) != MaxSize(%d)\n",
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TotalSizeUsed,
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MaxSize
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));
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return EFI_INVALID_PARAMETER;
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}
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if (Count > 0) {
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DEBUG ((
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EFI_D_INFO,
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"Restored %d Variables\n",
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Count
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));
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}
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return EFI_SUCCESS;
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}
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/**
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Examines the NvVars file contents, and updates variables based on it.
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@param[in] VarsBuffer - Buffer with NvVars data
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@param[in] VarsBufferSize - Size of VarsBuffer in bytes
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@return EFI_STATUS based on the success or failure of the operation
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**/
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EFI_STATUS
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SetVariablesFromBuffer (
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IN VOID *VarsBuffer,
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IN UINTN VarsBufferSize
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)
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{
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EFI_STATUS Status;
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//
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// First test to make sure the entire buffer is in a good state
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//
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Status = UnpackVariablesFromBuffer (VarsBuffer, VarsBufferSize, TRUE);
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if (EFI_ERROR (Status)) {
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DEBUG ((EFI_D_INFO, "NvVars buffer format was invalid\n"));
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return Status;
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}
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//
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// Now, actually restore the variables.
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//
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Status = UnpackVariablesFromBuffer (VarsBuffer, VarsBufferSize, FALSE);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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return Status;
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}
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