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Implement NvVarsFileLib to save and restore non-volatile variables using a file.

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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
This commit is contained in:
jljusten
2009-09-16 16:28:55 +00:00
parent af2cfce391
commit 5094454579
7 changed files with 1143 additions and 0 deletions
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345
OvmfPkg/Library/NvVarsFileLib/VarBuffer.c Normal file
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/** @file
File System Access
Copyright (c) 2004 - 2009, Intel Corporation. <BR>
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "NvVarsFileLib.h"
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
/**
Writes the variable into the file so it can be restored from
the file on future boots of the system.
@param[in] File - The file to write to
@param[in] Name - Variable name string
@param[in] NameSize - Size of Name in bytes
@param[in] Guid - GUID of variable
@param[in] Attributes - Attributes of variable
@param[in] Data - Buffer containing Data for variable
@param[in] DataSize - Size of Data in bytes
@return EFI_STATUS based on the success or failure of the operation
**/
EFI_STATUS
PackVariableIntoFile (
IN EFI_FILE_HANDLE File,
IN CHAR16 *Name,
IN UINT32 NameSize,
IN EFI_GUID *Guid,
IN UINT32 Attributes,
IN VOID *Data,
IN UINT32 DataSize
)
{
EFI_STATUS Status;
UINTN WriteSize;
WriteSize = sizeof (NameSize);
Status = FileHandleWrite (File, &WriteSize, &NameSize);
if (EFI_ERROR (Status)) {
return Status;
}
WriteSize = NameSize;
Status = FileHandleWrite (File, &WriteSize, (VOID*) Name);
if (EFI_ERROR (Status)) {
return Status;
}
WriteSize = sizeof (*Guid);
Status = FileHandleWrite (File, &WriteSize, (VOID*) Guid);
if (EFI_ERROR (Status)) {
return Status;
}
WriteSize = sizeof (Attributes);
Status = FileHandleWrite (File, &WriteSize, &Attributes);
if (EFI_ERROR (Status)) {
return Status;
}
WriteSize = sizeof (DataSize);
Status = FileHandleWrite (File, &WriteSize, &DataSize);
if (EFI_ERROR (Status)) {
return Status;
}
WriteSize = DataSize;
Status = FileHandleWrite (File, &WriteSize, Data);
return Status;
}
/**
Unpacks the next variable from the NvVars file data
@param[in] Buffer - Buffer pointing to the next variable instance
On subsequent calls, the pointer should be incremented
by the returned SizeUsed value.
@param[in] MaxSize - Max allowable size for the variable data
On subsequent calls, this should be decremented
by the returned SizeUsed value.
@param[out] Name - Variable name string (address in Buffer)
@param[out] NameSize - Size of Name in bytes
@param[out] Guid - GUID of variable (address in Buffer)
@param[out] Attributes - Attributes of variable
@param[out] Data - Buffer containing Data for variable (address in Buffer)
@param[out] DataSize - Size of Data in bytes
@param[out] SizeUsed - Total size used for this variable instance in Buffer
@return EFI_STATUS based on the success or failure of the operation
**/
EFI_STATUS
UnpackVariableFromBuffer (
IN VOID *Buffer,
IN UINTN MaxSize,
OUT CHAR16 **Name,
OUT UINT32 *NameSize,
OUT EFI_GUID **Guid,
OUT UINT32 *Attributes,
OUT UINT32 *DataSize,
OUT VOID **Data,
OUT UINTN *SizeUsed
)
{
UINT8 *BytePtr;
UINTN Offset;
BytePtr = (UINT8*)Buffer;
Offset = 0;
*NameSize = *(UINT32*) (BytePtr + Offset);
Offset = Offset + sizeof (UINT32);
if (Offset > MaxSize) {
return EFI_INVALID_PARAMETER;
}
*Name = (CHAR16*) (BytePtr + Offset);
Offset = Offset + *(UINT32*)BytePtr;
if (Offset > MaxSize) {
return EFI_INVALID_PARAMETER;
}
*Guid = (EFI_GUID*) (BytePtr + Offset);
Offset = Offset + sizeof (EFI_GUID);
if (Offset > MaxSize) {
return EFI_INVALID_PARAMETER;
}
*Attributes = *(UINT32*) (BytePtr + Offset);
Offset = Offset + sizeof (UINT32);
if (Offset > MaxSize) {
return EFI_INVALID_PARAMETER;
}
*DataSize = *(UINT32*) (BytePtr + Offset);
Offset = Offset + sizeof (UINT32);
if (Offset > MaxSize) {
return EFI_INVALID_PARAMETER;
}
*Data = (VOID*) (BytePtr + Offset);
Offset = Offset + *DataSize;
if (Offset > MaxSize) {
return EFI_INVALID_PARAMETER;
}
*SizeUsed = Offset;
return EFI_SUCCESS;
}
/**
Examines the NvVars file contents, and updates variables based on it.
@param[in] Buffer - Buffer with NvVars data
@param[in] MaxSize - Size of Buffer in bytes
@param[in] DryRun - If TRUE, then no variable modifications should be made
(If TRUE, the Buffer is still parsed for validity.)
@return EFI_STATUS based on the success or failure of the operation
**/
EFI_STATUS
UnpackVariablesFromBuffer (
IN VOID *Buffer,
IN UINTN MaxSize,
IN BOOLEAN DryRun
)
{
EFI_STATUS Status;
UINTN Count;
UINTN TotalSizeUsed;
UINTN SizeUsed;
CHAR16 *Name;
UINT32 NameSize;
CHAR16 *AlignedName;
UINT32 AlignedNameMaxSize;
EFI_GUID *Guid;
UINT32 Attributes;
UINT32 DataSize;
VOID *Data;
AlignedName = NULL;
AlignedNameMaxSize = 0;
for (
Status = EFI_SUCCESS, Count = 0, TotalSizeUsed = 0;
!EFI_ERROR (Status) && (TotalSizeUsed < MaxSize);
) {
Status = UnpackVariableFromBuffer (
(VOID*) ((UINT8*) Buffer + TotalSizeUsed),
(MaxSize - TotalSizeUsed),
&Name,
&NameSize,
&Guid,
&Attributes,
&DataSize,
&Data,
&SizeUsed
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// We copy the name to a separately allocated buffer,
// to be sure it is 16-bit aligned.
//
if (NameSize > AlignedNameMaxSize) {
if (AlignedName != NULL) {
FreePool (AlignedName);
}
AlignedName = AllocatePool (NameSize);
}
if (AlignedName == NULL) {
return EFI_OUT_OF_RESOURCES;
}
CopyMem (AlignedName, Name, NameSize);
DEBUG ((
EFI_D_INFO,
"Unpacked variable %g:%s\n",
Guid,
AlignedName
));
TotalSizeUsed = TotalSizeUsed + SizeUsed;
DEBUG ((
EFI_D_INFO,
"TotalSizeUsed(%d); MaxSize(%d)\n",
TotalSizeUsed,
MaxSize
));
if (!DryRun) {
//
// Set the variable contents
//
gRT->SetVariable (
AlignedName,
Guid,
Attributes,
DataSize,
Data
);
Count++;
DEBUG ((
EFI_D_INFO,
"Restored variable %g:%s\n",
Guid,
AlignedName
));
}
}
if (AlignedName != NULL) {
FreePool (AlignedName);
}
//
// Make sure the entire buffer was used, or else return an error
//
if (TotalSizeUsed != MaxSize) {
DEBUG ((
EFI_D_INFO,
"TotalSizeUsed(%d) != MaxSize(%d)\n",
TotalSizeUsed,
MaxSize
));
return EFI_INVALID_PARAMETER;
}
if (Count > 0) {
DEBUG ((
EFI_D_INFO,
"Restored %d Variables\n",
Count
));
}
return EFI_SUCCESS;
}
/**
Examines the NvVars file contents, and updates variables based on it.
@param[in] VarsBuffer - Buffer with NvVars data
@param[in] VarsBufferSize - Size of VarsBuffer in bytes
@return EFI_STATUS based on the success or failure of the operation
**/
EFI_STATUS
SetVariablesFromBuffer (
IN VOID *VarsBuffer,
IN UINTN VarsBufferSize
)
{
EFI_STATUS Status;
//
// First test to make sure the entire buffer is in a good state
//
Status = UnpackVariablesFromBuffer (VarsBuffer, VarsBufferSize, TRUE);
if (EFI_ERROR (Status)) {
DEBUG ((EFI_D_INFO, "NvVars buffer format was invalid\n"));
return Status;
}
//
// Now, actually restore the variables.
//
Status = UnpackVariablesFromBuffer (VarsBuffer, VarsBufferSize, FALSE);
if (EFI_ERROR (Status)) {
return Status;
}
return Status;
}