Syncboot/efi/lib/sread.c
Curle 4300dc655c Add EFI documentation, libraries and includes.
The lib/inc folders are from the GNU-EFI project.
The documentation is from the uefi.org site.

Yes, I know there are duplicate includes. I have a plan for them.
2019-07-17 15:11:52 +01:00

359 lines
8.1 KiB
C

/*++
Copyright (c) 1998 Intel Corporation
Module Name:
sread.c
Abstract:
Simple read file access
Revision History
--*/
#include "lib.h"
#define SIMPLE_READ_SIGNATURE EFI_SIGNATURE_32('s','r','d','r')
typedef struct _SIMPLE_READ_FILE {
UINTN Signature;
BOOLEAN FreeBuffer;
VOID *Source;
UINTN SourceSize;
EFI_FILE_HANDLE FileHandle;
} SIMPLE_READ_HANDLE;
EFI_STATUS
OpenSimpleReadFile (
IN BOOLEAN BootPolicy,
IN VOID *SourceBuffer OPTIONAL,
IN UINTN SourceSize,
IN OUT EFI_DEVICE_PATH **FilePath,
OUT EFI_HANDLE *DeviceHandle,
OUT SIMPLE_READ_FILE *SimpleReadHandle
)
/*++
Routine Description:
Opens a file for (simple) reading. The simple read abstraction
will access the file either from a memory copy, from a file
system interface, or from the load file interface.
Arguments:
Returns:
A handle to access the file
--*/
{
SIMPLE_READ_HANDLE *FHand;
EFI_DEVICE_PATH *UserFilePath;
EFI_DEVICE_PATH *TempFilePath;
EFI_DEVICE_PATH *TempFilePathPtr;
FILEPATH_DEVICE_PATH *FilePathNode;
EFI_FILE_HANDLE FileHandle, LastHandle;
EFI_STATUS Status;
EFI_LOAD_FILE_INTERFACE *LoadFile;
FHand = NULL;
UserFilePath = *FilePath;
//
// Allocate a new simple read handle structure
//
FHand = AllocateZeroPool (sizeof(SIMPLE_READ_HANDLE));
if (!FHand) {
Status = EFI_OUT_OF_RESOURCES;
goto Done;
}
*SimpleReadHandle = (SIMPLE_READ_FILE) FHand;
FHand->Signature = SIMPLE_READ_SIGNATURE;
//
// If the caller passed a copy of the file, then just use it
//
if (SourceBuffer) {
FHand->Source = SourceBuffer;
FHand->SourceSize = SourceSize;
*DeviceHandle = NULL;
Status = EFI_SUCCESS;
goto Done;
}
//
// Attempt to access the file via a file system interface
//
FileHandle = NULL;
Status = uefi_call_wrapper(BS->LocateDevicePath, 3, &FileSystemProtocol, FilePath, DeviceHandle);
if (!EFI_ERROR(Status)) {
FileHandle = LibOpenRoot (*DeviceHandle);
}
Status = FileHandle ? EFI_SUCCESS : EFI_UNSUPPORTED;
//
// To access as a filesystem, the filepath should only
// contain filepath components. Follow the filepath nodes
// and find the target file
//
FilePathNode = (FILEPATH_DEVICE_PATH *) *FilePath;
while (!IsDevicePathEnd(&FilePathNode->Header)) {
//
// For filesystem access each node should be a filepath component
//
if (DevicePathType(&FilePathNode->Header) != MEDIA_DEVICE_PATH ||
DevicePathSubType(&FilePathNode->Header) != MEDIA_FILEPATH_DP) {
Status = EFI_UNSUPPORTED;
}
//
// If there's been an error, stop
//
if (EFI_ERROR(Status)) {
break;
}
//
// Open this file path node
//
LastHandle = FileHandle;
FileHandle = NULL;
Status = uefi_call_wrapper(
LastHandle->Open,
5,
LastHandle,
&FileHandle,
FilePathNode->PathName,
EFI_FILE_MODE_READ,
0
);
//
// Close the last node
//
uefi_call_wrapper(LastHandle->Close, 1, LastHandle);
//
// Get the next node
//
FilePathNode = (FILEPATH_DEVICE_PATH *) NextDevicePathNode(&FilePathNode->Header);
}
//
// If success, return the FHand
//
if (!EFI_ERROR(Status)) {
ASSERT(FileHandle);
FHand->FileHandle = FileHandle;
goto Done;
}
//
// Cleanup from filesystem access
//
if (FileHandle) {
uefi_call_wrapper(FileHandle->Close, 1, FileHandle);
FileHandle = NULL;
*FilePath = UserFilePath;
}
//
// If the error is something other then unsupported, return it
//
if (Status != EFI_UNSUPPORTED) {
goto Done;
}
//
// Attempt to access the file via the load file protocol
//
Status = LibDevicePathToInterface (&LoadFileProtocol, *FilePath, (VOID*)&LoadFile);
if (!EFI_ERROR(Status)) {
TempFilePath = DuplicateDevicePath (*FilePath);
TempFilePathPtr = TempFilePath;
Status = uefi_call_wrapper(BS->LocateDevicePath, 3, &LoadFileProtocol, &TempFilePath, DeviceHandle);
FreePool (TempFilePathPtr);
//
// Determine the size of buffer needed to hold the file
//
SourceSize = 0;
Status = uefi_call_wrapper(
LoadFile->LoadFile,
5,
LoadFile,
*FilePath,
BootPolicy,
&SourceSize,
NULL
);
//
// We expect a buffer too small error to inform us
// of the buffer size needed
//
if (Status == EFI_BUFFER_TOO_SMALL) {
SourceBuffer = AllocatePool (SourceSize);
if (SourceBuffer) {
FHand->FreeBuffer = TRUE;
FHand->Source = SourceBuffer;
FHand->SourceSize = SourceSize;
Status = uefi_call_wrapper(
LoadFile->LoadFile,
5,
LoadFile,
*FilePath,
BootPolicy,
&SourceSize,
SourceBuffer
);
}
}
//
// If success, return FHand
//
if (!EFI_ERROR(Status) || Status == EFI_ALREADY_STARTED) {
goto Done;
}
}
//
// Nothing else to try
//
DEBUG ((D_LOAD|D_WARN, "OpenSimpleReadFile: Device did not support a known load protocol\n"));
Status = EFI_UNSUPPORTED;
Done:
//
// If the file was not accessed, clean up
//
if (EFI_ERROR(Status) && (Status != EFI_ALREADY_STARTED)) {
if (FHand) {
if (FHand->FreeBuffer) {
FreePool (FHand->Source);
}
FreePool (FHand);
}
}
return Status;
}
EFI_STATUS
ReadSimpleReadFile (
IN SIMPLE_READ_FILE UserHandle,
IN UINTN Offset,
IN OUT UINTN *ReadSize,
OUT VOID *Buffer
)
{
UINTN EndPos;
SIMPLE_READ_HANDLE *FHand;
EFI_STATUS Status;
FHand = UserHandle;
ASSERT (FHand->Signature == SIMPLE_READ_SIGNATURE);
if (FHand->Source) {
//
// Move data from our local copy of the file
//
EndPos = Offset + *ReadSize;
if (EndPos > FHand->SourceSize) {
*ReadSize = FHand->SourceSize - Offset;
if (Offset >= FHand->SourceSize) {
*ReadSize = 0;
}
}
CopyMem (Buffer, (CHAR8 *) FHand->Source + Offset, *ReadSize);
Status = EFI_SUCCESS;
} else {
//
// Read data from the file
//
Status = uefi_call_wrapper(FHand->FileHandle->SetPosition, 2, FHand->FileHandle, Offset);
if (!EFI_ERROR(Status)) {
Status = uefi_call_wrapper(FHand->FileHandle->Read, 3, FHand->FileHandle, ReadSize, Buffer);
}
}
return Status;
}
VOID
CloseSimpleReadFile (
IN SIMPLE_READ_FILE UserHandle
)
{
SIMPLE_READ_HANDLE *FHand;
FHand = UserHandle;
ASSERT (FHand->Signature == SIMPLE_READ_SIGNATURE);
//
// Free any file handle we opened
//
if (FHand->FileHandle) {
uefi_call_wrapper(FHand->FileHandle->Close, 1, FHand->FileHandle);
}
//
// If we allocated the Source buffer, free it
//
if (FHand->FreeBuffer) {
FreePool (FHand->Source);
}
//
// Done with this simple read file handle
//
FreePool (FHand);
}