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audk/EmbeddedPkg/Library/EfiFileLib/EfiFileLib.c

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/** @file
File IO routines inspired by Streams with an EFI flavor
Copyright (c) 2007, Intel Corporation<BR>
Portions copyright (c) 2008-2009, Apple Inc. All rights reserved.
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.
Basic support for opening files on different device types. The device string
is in the form of DevType:Path. Current DevType is required as there is no
current mounted device concept of current working directory concept implement
by this library.
Device names are case insensative and only check the leading characters for
unique matches. Thus the following are all the same:
LoadFile0:
l0:
L0:
Lo0:
Supported Device Names:
A0x1234:0x12 - A memory buffer starting at address 0x1234 for 0x12 bytes
l1: - EFI LoadFile device one.
B0: - EFI BlockIo zero.
fs3: - EFI Simple File System device 3
Fv2: - EFI Firmware VOlume device 2
10.0.1.102: - TFTP service IP followed by the file name
**/
#include <PiDxe.h>
#include <Protocol/BlockIo.h>
#include <Protocol/DiskIo.h>
#include <Protocol/SimpleFileSystem.h>
#include <Protocol/FirmwareVolume2.h>
#include <Protocol/LoadFile.h>
#include <Protocol/FirmwareVolumeBlock.h>
#include <Guid/FileInfo.h>
#include <Library/BaseLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/DevicePathLib.h>
#include <Library/PrintLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/UefiLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
#include <Library/DebugLib.h>
#include <Library/EfiFileLib.h>
#include <Library/PcdLib.h>
#include <Library/EblNetworkLib.h>
CHAR8 *gCwd = NULL;
#define EFI_OPEN_FILE_GUARD_HEADER 0x4B4D4641
#define EFI_OPEN_FILE_GUARD_FOOTER 0x444D5A56
// Need to defend against this overflowing
#define MAX_CMD_LINE 0x200
typedef struct {
UINT32 Header;
EFI_OPEN_FILE File;
UINT32 Footer;
} EFI_OPEN_FILE_GUARD;
// globals to store current open device info
EFI_HANDLE *mBlkIo = NULL;
UINTN mBlkIoCount = 0;
EFI_HANDLE *mFs = NULL;
UINTN mFsCount = 0;
// mFsInfo[] array entries must match mFs[] handles
EFI_FILE_SYSTEM_INFO **mFsInfo = NULL;
EFI_HANDLE *mFv = NULL;
UINTN mFvCount = 0;
EFI_HANDLE *mLoadFile = NULL;
UINTN mLoadFileCount = 0;
/**
Internal worker function to validate a File handle.
@param File Open File Handle
@return TRUE File is valid
@return FALSE File is not valid
**/
BOOLEAN
FileHandleValid (
IN EFI_OPEN_FILE *File
)
{
EFI_OPEN_FILE_GUARD *GuardFile;
// Look right before and after file structure for the correct signatures
GuardFile = BASE_CR (File, EFI_OPEN_FILE_GUARD, File);
if ((GuardFile->Header != EFI_OPEN_FILE_GUARD_HEADER) ||
(GuardFile->Footer != EFI_OPEN_FILE_GUARD_FOOTER) ) {
return FALSE;
}
return TRUE;
}
/**
Internal worker function. If Buffer is not NULL free it.
@param Buffer Buffer to FreePool()
**/
VOID
EblFreePool (
IN VOID *Buffer
)
{
if (Buffer != NULL) {
FreePool (Buffer);
}
}
/**
Update Device List Global Variables
**/
VOID
EblUpdateDeviceLists (
VOID
)
{
EFI_STATUS Status;
UINTN Size;
EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *Fs;
EFI_FILE_HANDLE Root;
UINTN Index;
if (mBlkIo != NULL) {
FreePool (mBlkIo);
}
gBS->LocateHandleBuffer (ByProtocol, &gEfiBlockIoProtocolGuid, NULL, &mBlkIoCount, &mBlkIo);
if (mFv != NULL) {
FreePool (mFv);
}
gBS->LocateHandleBuffer (ByProtocol, &gEfiFirmwareVolume2ProtocolGuid, NULL, &mFvCount, &mFv);
if (mLoadFile != NULL) {
FreePool (mLoadFile);
}
gBS->LocateHandleBuffer (ByProtocol, &gEfiLoadFileProtocolGuid, NULL, &mLoadFileCount, &mLoadFile);
if (mFs != NULL) {
FreePool (mFs);
}
if (&mFsInfo[0] != NULL) {
// Need to Free the mFsInfo prior to reclaculating mFsCount so don't move this code
for (Index = 0; Index < mFsCount; Index++) {
if (mFsInfo[Index] != NULL) {
FreePool (mFsInfo[Index]);
}
}
FreePool (mFsInfo);
}
gBS->LocateHandleBuffer (ByProtocol, &gEfiSimpleFileSystemProtocolGuid, NULL, &mFsCount, &mFs);
mFsInfo = AllocateZeroPool (mFsCount * sizeof (EFI_FILE_SYSTEM_INFO *));
if (mFsInfo == NULL) {
// If we can't do this then we can't support file system entries
mFsCount = 0;
} else {
// Loop through all the file system structures and cache the file system info data
for (Index =0; Index < mFsCount; Index++) {
Status = gBS->HandleProtocol (mFs[Index], &gEfiSimpleFileSystemProtocolGuid, (VOID **)&Fs);
if (!EFI_ERROR (Status)) {
Status = Fs->OpenVolume (Fs, &Root);
if (!EFI_ERROR (Status)) {
// Get information about the volume
Size = 0;
Status = Root->GetInfo (Root, &gEfiFileSystemInfoGuid, &Size, mFsInfo[Index]);
if (Status == EFI_BUFFER_TOO_SMALL) {
mFsInfo[Index] = AllocatePool (Size);
Status = Root->GetInfo (Root, &gEfiFileSystemInfoGuid, &Size, mFsInfo[Index]);
}
Root->Close (Root);
}
}
}
}
}
/**
PathName is in the form <device name>:<path> for example fs1:\ or ROOT:\.
Return TRUE if the <devce name> prefix of PathName matches a file system
Volume Name. MatchIndex is the array index in mFsInfo[] of the match,
and it can be used with mFs[] to find the handle that needs to be opened
@param PathName PathName to check
@param FileStart Index of the first character of the <path>
@param MatchIndex Index in mFsInfo[] that matches
@return TRUE PathName matches a Volume Label and MatchIndex is valid
@return FALSE PathName does not match a Volume Label MatchIndex undefined
**/
BOOLEAN
EblMatchVolumeName (
IN CHAR8 *PathName,
IN UINTN FileStart,
OUT UINTN *MatchIndex
)
{
UINTN Index;
UINTN Compare;
UINTN VolStrLen;
BOOLEAN Match;
for (Index =0; Index < mFsCount; Index++) {
if (mFsInfo[Index] == NULL) {
// FsInfo is not valid so skip it
continue;
}
VolStrLen = StrLen (mFsInfo[Index]->VolumeLabel);
for (Compare = 0, Match = TRUE; Compare < (FileStart - 1); Compare++) {
if (Compare > VolStrLen) {
Match = FALSE;
break;
}
if (PathName[Compare] != (CHAR8)mFsInfo[Index]->VolumeLabel[Compare]) {
// If the VolumeLabel has a space allow a _ to match with it in addition to ' '
if (!((PathName[Compare] == '_') && (mFsInfo[Index]->VolumeLabel[Compare] == L' '))) {
Match = FALSE;
break;
}
}
}
if (Match) {
*MatchIndex = Index;
return TRUE;
}
}
return FALSE;
}
/**
Return the number of devices of the current type active in the system
@param Type Device type to check
@return 0 Invalid type
**/
UINTN
EfiGetDeviceCounts (
IN EFI_OPEN_FILE_TYPE DeviceType
)
{
switch (DeviceType) {
case EfiOpenLoadFile:
return mLoadFileCount;
case EfiOpenFirmwareVolume:
return mFvCount;
case EfiOpenFileSystem:
return mFsCount;
case EfiOpenBlockIo:
return mBlkIoCount;
default:
return 0;
}
}
EFI_STATUS
ConvertIpStringToEfiIp (
IN CHAR8 *PathName,
OUT EFI_IP_ADDRESS *ServerIp
)
{
CHAR8 *Str;
Str = PathName;
ServerIp->v4.Addr[0] = (UINT8)AsciiStrDecimalToUintn (Str);
Str = AsciiStrStr (Str, ".");
if (Str == NULL) {
return EFI_DEVICE_ERROR;
}
ServerIp->v4.Addr[1] = (UINT8)AsciiStrDecimalToUintn (++Str);
Str = AsciiStrStr (Str, ".");
if (Str == NULL) {
return EFI_DEVICE_ERROR;
}
ServerIp->v4.Addr[2] = (UINT8)AsciiStrDecimalToUintn (++Str);
Str = AsciiStrStr (Str, ".");
if (Str == NULL) {
return EFI_DEVICE_ERROR;
}
ServerIp->v4.Addr[3] = (UINT8)AsciiStrDecimalToUintn (++Str);
return EFI_SUCCESS;
}
/**
Internal work function to extract a device number from a string skipping
text. Easy way to extract numbers from strings like blk7:.
@param Str String to extract device number form
@return -1 Device string is not valid
@return Device #
**/
UINTN
EblConvertDevStringToNumber (
IN CHAR8 *Str
)
{
UINTN Max;
UINTN Index;
// Find the first digit
Max = AsciiStrLen (Str);
for (Index = 0; !((*Str >= '0') && (*Str <= '9')) && (Index < Max); Index++) {
Str++;
}
if (Index == Max) {
return (UINTN)-1;
}
return AsciiStrDecimalToUintn (Str);
}
/**
Internal work function to fill in EFI_OPEN_FILE information for the Fs and BlkIo
@param File Open file handle
@param FileName Name of file after device stripped off
**/
EFI_STATUS
EblFileDevicePath (
IN OUT EFI_OPEN_FILE *File,
IN CHAR8 *FileName,
IN CONST UINT64 OpenMode
)
{
EFI_STATUS Status;
UINTN Size;
FILEPATH_DEVICE_PATH *FilePath;
EFI_DEVICE_PATH_PROTOCOL *FileDevicePath;
CHAR16 UnicodeFileName[MAX_PATHNAME];
EFI_BLOCK_IO_PROTOCOL *BlkIo;
EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *Fs;
EFI_FILE_HANDLE Root;
if ( *FileName != 0 ) {
AsciiStrToUnicodeStr (FileName, UnicodeFileName);
} else {
AsciiStrToUnicodeStr ("\\", UnicodeFileName);
}
Size = StrSize (UnicodeFileName);
FileDevicePath = AllocatePool (Size + SIZE_OF_FILEPATH_DEVICE_PATH + sizeof (EFI_DEVICE_PATH_PROTOCOL));
if (FileDevicePath != NULL) {
FilePath = (FILEPATH_DEVICE_PATH *) FileDevicePath;
FilePath->Header.Type = MEDIA_DEVICE_PATH;
FilePath->Header.SubType = MEDIA_FILEPATH_DP;
CopyMem (&FilePath->PathName, UnicodeFileName, Size);
SetDevicePathNodeLength (&FilePath->Header, Size + SIZE_OF_FILEPATH_DEVICE_PATH);
SetDevicePathEndNode (NextDevicePathNode (&FilePath->Header));
if (File->EfiHandle != NULL) {
File->DevicePath = DevicePathFromHandle (File->EfiHandle);
}
File->DevicePath = AppendDevicePath (File->DevicePath, FileDevicePath);
FreePool (FileDevicePath);
}
Status = gBS->HandleProtocol (File->EfiHandle, &gEfiBlockIoProtocolGuid, (VOID **)&BlkIo);
if (!EFI_ERROR (Status)) {
CopyMem (&File->FsBlockIoMedia, BlkIo->Media, sizeof (EFI_BLOCK_IO_MEDIA));
// If we are not opening the device this will get over written with file info
File->MaxPosition = MultU64x32 (BlkIo->Media->LastBlock + 1, BlkIo->Media->BlockSize);
}
if (File->Type == EfiOpenFileSystem) {
Status = gBS->HandleProtocol (File->EfiHandle, &gEfiSimpleFileSystemProtocolGuid, (VOID **)&Fs);
if (!EFI_ERROR (Status)) {
Status = Fs->OpenVolume (Fs, &Root);
if (!EFI_ERROR (Status)) {
// Get information about the volume
Size = 0;
Status = Root->GetInfo (Root, &gEfiFileSystemInfoGuid, &Size, File->FsInfo);
if (Status == EFI_BUFFER_TOO_SMALL) {
File->FsInfo = AllocatePool (Size);
Status = Root->GetInfo (Root, &gEfiFileSystemInfoGuid, &Size, File->FsInfo);
}
// Get information about the file
Status = Root->Open (Root, &File->FsFileHandle, UnicodeFileName, OpenMode, 0);
if (!EFI_ERROR (Status)) {
Size = 0;
Status = File->FsFileHandle->GetInfo (File->FsFileHandle, &gEfiFileInfoGuid, &Size, NULL);
if (Status == EFI_BUFFER_TOO_SMALL) {
File->FsFileInfo = AllocatePool (Size);
Status = File->FsFileHandle->GetInfo (File->FsFileHandle, &gEfiFileInfoGuid, &Size, File->FsFileInfo);
if (!EFI_ERROR (Status)) {
File->Size = (UINTN)File->FsFileInfo->FileSize;
File->MaxPosition = (UINT64)File->Size;
}
}
}
Root->Close (Root);
}
}
} else if (File->Type == EfiOpenBlockIo) {
File->Size = (UINTN)File->MaxPosition;
}
return Status;
}
#define ToUpper(a) ((((a) >= 'a') && ((a) <= 'z')) ? ((a) - 'a' + 'A') : (a))
EFI_STATUS
CompareGuidToString (
IN EFI_GUID *Guid,
IN CHAR8 *String
)
{
CHAR8 AsciiGuid[64];
CHAR8 *StringPtr;
CHAR8 *GuidPtr;
AsciiSPrint (AsciiGuid, sizeof(AsciiGuid), "%g", Guid);
StringPtr = String;
GuidPtr = AsciiGuid;
while ((*StringPtr != '\0') && (*GuidPtr != '\0')) {
// Skip dashes
if (*StringPtr == '-') {
StringPtr++;
continue;
}
if (*GuidPtr == '-') {
GuidPtr++;
continue;
}
if (ToUpper(*StringPtr) != ToUpper(*GuidPtr)) {
return EFI_NOT_FOUND;
}
StringPtr++;
GuidPtr++;
}
return EFI_SUCCESS;
}
/**
Internal work function to fill in EFI_OPEN_FILE information for the FV
@param File Open file handle
@param FileName Name of file after device stripped off
**/
EFI_STATUS
EblFvFileDevicePath (
IN OUT EFI_OPEN_FILE *File,
IN CHAR8 *FileName,
IN CONST UINT64 OpenMode
)
{
EFI_STATUS Status;
EFI_STATUS GetNextFileStatus;
MEDIA_FW_VOL_FILEPATH_DEVICE_PATH DevicePathNode;
EFI_DEVICE_PATH_PROTOCOL *DevicePath;
UINTN Key;
UINT32 AuthenticationStatus;
CHAR8 AsciiSection[MAX_PATHNAME];
VOID *Section;
UINTN SectionSize;
EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL *Fvb;
EFI_LBA Lba;
UINTN BlockSize;
UINTN NumberOfBlocks;
Status = gBS->HandleProtocol (File->EfiHandle, &gEfiFirmwareVolume2ProtocolGuid, (VOID **)&File->Fv);
if (EFI_ERROR (Status)) {
return Status;
}
DevicePath = DevicePathFromHandle (File->EfiHandle);
if (*FileName == '\0') {
File->DevicePath = DuplicateDevicePath (DevicePath);
} else {
Key = 0;
do {
File->FvType = EFI_FV_FILETYPE_ALL;
GetNextFileStatus = File->Fv->GetNextFile (
File->Fv,
&Key,
&File->FvType,
&File->FvNameGuid,
&File->FvAttributes,
&File->Size
);
if (!EFI_ERROR (GetNextFileStatus)) {
Section = NULL;
// Compare GUID first
Status = CompareGuidToString (&File->FvNameGuid, FileName);
if (!EFI_ERROR(Status)) {
break;
}
Status = File->Fv->ReadSection (
File->Fv,
&File->FvNameGuid,
EFI_SECTION_USER_INTERFACE,
0,
&Section,
&SectionSize,
&AuthenticationStatus
);
if (!EFI_ERROR (Status)) {
UnicodeStrToAsciiStr (Section, AsciiSection);
if (AsciiStriCmp (FileName, AsciiSection) == 0) {
FreePool (Section);
break;
}
FreePool (Section);
}
}
} while (!EFI_ERROR (GetNextFileStatus));
if (EFI_ERROR (GetNextFileStatus)) {
return GetNextFileStatus;
}
File->MaxPosition = File->Size;
EfiInitializeFwVolDevicepathNode (&DevicePathNode, &File->FvNameGuid);
File->DevicePath = AppendDevicePathNode (DevicePath, (EFI_DEVICE_PATH_PROTOCOL *)&DevicePathNode);
}
// Get FVB Info about the handle
Status = gBS->HandleProtocol (File->EfiHandle, &gEfiFirmwareVolumeBlockProtocolGuid, (VOID **)&Fvb);
if (!EFI_ERROR (Status)) {
Status = Fvb->GetPhysicalAddress (Fvb, &File->FvStart);
if (!EFI_ERROR (Status)) {
for (Lba = 0, File->FvSize = 0; ; File->FvSize += (BlockSize * NumberOfBlocks), Lba += NumberOfBlocks) {
Status = Fvb->GetBlockSize (Fvb, Lba, &BlockSize, &NumberOfBlocks);
if (EFI_ERROR (Status)) {
break;
}
}
}
}
// FVB not required if FV was soft loaded...
return EFI_SUCCESS;
}
/**
Open a device named by PathName. The PathName includes a device name and
path seperated by a :. See file header for more details on the PathName
syntax. There is no checking to prevent a file from being opened more than
one type.
SectionType is only used to open an FV. Each file in an FV contains multiple
secitons and only the SectionType section is opened.
For any file that is opened with EfiOpen() must be closed with EfiClose().
@param PathName Path to parse to open
@param OpenMode Same as EFI_FILE.Open()
@param SectionType Section in FV to open.
@return NULL Open failed
@return Valid EFI_OPEN_FILE handle
**/
EFI_OPEN_FILE *
EfiOpen (
IN CHAR8 *PathName,
IN CONST UINT64 OpenMode,
IN CONST EFI_SECTION_TYPE SectionType
)
{
EFI_STATUS Status;
EFI_OPEN_FILE *File;
EFI_OPEN_FILE FileData;
UINTN StrLen;
UINTN FileStart;
UINTN DevNumber = 0;
EFI_OPEN_FILE_GUARD *GuardFile;
BOOLEAN VolumeNameMatch;
EFI_DEVICE_PATH_PROTOCOL *DevicePath;
UINTN Size;
EFI_IP_ADDRESS Ip;
CHAR8 *CwdPlusPathName;
EblUpdateDeviceLists ();
File = &FileData;
ZeroMem (File, sizeof (EFI_OPEN_FILE));
File->FvSectionType = SectionType;
StrLen = AsciiStrSize (PathName);
if (StrLen <= 1) {
// Smallest valid path is 1 char and a null
return NULL;
}
for (FileStart = 0; FileStart < StrLen; FileStart++) {
if (PathName[FileStart] == ':') {
FileStart++;
break;
}
}
//
// Matching volume name has precedence over handle based names
//
VolumeNameMatch = EblMatchVolumeName (PathName, FileStart, &DevNumber);
if (!VolumeNameMatch) {
if (FileStart == StrLen) {
// No Volume name or device name, so try Current Working Directory
if (gCwd == NULL) {
// No CWD
return NULL;
}
// We could add a current working diretory concept
CwdPlusPathName = AllocatePool (AsciiStrSize (gCwd) + AsciiStrSize (PathName));
if (CwdPlusPathName == NULL) {
return NULL;
}
if ((PathName[0] == '/') || (PathName[0] == '\\')) {
// PathName starts in / so this means we go to the root of the device in the CWD.
CwdPlusPathName[0] = '\0';
for (FileStart = 0; gCwd[FileStart] != '\0'; FileStart++) {
CwdPlusPathName[FileStart] = gCwd[FileStart];
if (gCwd[FileStart] == ':') {
FileStart++;
CwdPlusPathName[FileStart] = '\0';
break;
}
}
} else {
AsciiStrCpy (CwdPlusPathName, gCwd);
StrLen = AsciiStrLen (gCwd);
if ((*PathName != '/') && (*PathName != '\\') && (gCwd[StrLen-1] != '/') && (gCwd[StrLen-1] != '\\')) {
AsciiStrCat (CwdPlusPathName, "\\");
}
}
AsciiStrCat (CwdPlusPathName, PathName);
if (AsciiStrStr (CwdPlusPathName, ":") == NULL) {
// Extra error check to make sure we don't recusre and blow stack
return NULL;
}
File = EfiOpen (CwdPlusPathName, OpenMode, SectionType);
FreePool (CwdPlusPathName);
return File;
}
DevNumber = EblConvertDevStringToNumber ((CHAR8 *)PathName);
}
File->DeviceName = AllocatePool (StrLen);
AsciiStrCpy (File->DeviceName, PathName);
File->DeviceName[FileStart - 1] = '\0';
File->FileName = &File->DeviceName[FileStart];
if (File->FileName[0] == '\0') {
// if it is just a file name use / as root
File->FileName = "\\";
}
//
// Use best match algorithm on the dev names so we only need to look at the
// first few charters to match the full device name. Short name forms are
// legal from the caller.
//
Status = EFI_SUCCESS;
if (*PathName == 'f' || *PathName == 'F' || VolumeNameMatch) {
if (PathName[1] == 's' || PathName[1] == 'S' || VolumeNameMatch) {
if (DevNumber >= mFsCount) {
goto ErrorExit;
}
File->Type = EfiOpenFileSystem;
File->EfiHandle = mFs[DevNumber];
Status = EblFileDevicePath (File, &PathName[FileStart], OpenMode);
} else if (PathName[1] == 'v' || PathName[1] == 'V') {
if (DevNumber >= mFvCount) {
goto ErrorExit;
}
File->Type = EfiOpenFirmwareVolume;
File->EfiHandle = mFv[DevNumber];
if ((PathName[FileStart] == '/') || (PathName[FileStart] == '\\')) {
// Skip leading / as its not really needed for the FV since no directories are supported
FileStart++;
}
Status = EblFvFileDevicePath (File, &PathName[FileStart], OpenMode);
}
} else if ((*PathName == 'A') || (*PathName == 'a')) {
// Handle a:0x10000000:0x1234 address form a:ADDRESS:SIZE
File->Type = EfiOpenMemoryBuffer;
// 1st colon is at PathName[FileStart - 1]
File->Buffer = (VOID *)AsciiStrHexToUintn (&PathName[FileStart]);
// Find 2nd colon
while ((PathName[FileStart] != ':') && (PathName[FileStart] != '\0')) {
FileStart++;
}
// If we ran out of string, there's no extra data
if (PathName[FileStart] == '\0') {
File->Size = 0;
} else {
File->Size = AsciiStrHexToUintn (&PathName[FileStart + 1]);
}
// if there's no number after the second colon, default
// the end of memory
if (File->Size == 0) {
File->Size = (UINTN)(0 - (UINTN)File->Buffer);
}
File->MaxPosition = File->Size;
File->BaseOffset = (UINTN)File->Buffer;
} else if (*PathName== 'l' || *PathName == 'L') {
if (DevNumber >= mLoadFileCount) {
goto ErrorExit;
}
File->Type = EfiOpenLoadFile;
File->EfiHandle = mLoadFile[DevNumber];
Status = gBS->HandleProtocol (File->EfiHandle, &gEfiLoadFileProtocolGuid, (VOID **)&File->LoadFile);
if (EFI_ERROR (Status)) {
goto ErrorExit;
}
Status = gBS->HandleProtocol (File->EfiHandle, &gEfiDevicePathProtocolGuid, (VOID **)&DevicePath);
if (EFI_ERROR (Status)) {
goto ErrorExit;
}
File->DevicePath = DuplicateDevicePath (DevicePath);
} else if (*PathName == 'b' || *PathName == 'B') {
// Handle b#:0x10000000:0x1234 address form b#:ADDRESS:SIZE
if (DevNumber >= mBlkIoCount) {
goto ErrorExit;
}
File->Type = EfiOpenBlockIo;
File->EfiHandle = mBlkIo[DevNumber];
EblFileDevicePath (File, "", OpenMode);
// 1st colon is at PathName[FileStart - 1]
File->DiskOffset = AsciiStrHexToUintn (&PathName[FileStart]);
// Find 2nd colon
while ((PathName[FileStart] != ':') && (PathName[FileStart] != '\0')) {
FileStart++;
}
// If we ran out of string, there's no extra data
if (PathName[FileStart] == '\0') {
Size = 0;
} else {
Size = AsciiStrHexToUintn (&PathName[FileStart + 1]);
}
// if a zero size is passed in (or the size is left out entirely),
// go to the end of the device.
if (Size == 0) {
File->Size = File->Size - File->DiskOffset;
} else {
File->Size = Size;
}
File->MaxPosition = File->Size;
File->BaseOffset = File->DiskOffset;
} else if ((*PathName) >= '0' && (*PathName <= '9')) {
// Get current IP address
Status = EblGetCurrentIpAddress (&Ip);
if (EFI_ERROR(Status)) {
AsciiPrint("Device IP Address is not configured.\n");
goto ErrorExit;
}
// Parse X.X.X.X:Filename, only support IPv4 TFTP for now...
File->Type = EfiOpenTftp;
File->IsDirty = FALSE;
File->IsBufferValid = FALSE;
Status = ConvertIpStringToEfiIp (PathName, &File->ServerIp);
}
if (EFI_ERROR (Status)) {
goto ErrorExit;
}
GuardFile = (EFI_OPEN_FILE_GUARD *)AllocateZeroPool (sizeof (EFI_OPEN_FILE_GUARD));
if (GuardFile == NULL) {
goto ErrorExit;
}
GuardFile->Header = EFI_OPEN_FILE_GUARD_HEADER;
CopyMem (&(GuardFile->File), &FileData, sizeof (EFI_OPEN_FILE));
GuardFile->Footer = EFI_OPEN_FILE_GUARD_FOOTER;
return &(GuardFile->File);
ErrorExit:
FreePool (File->DeviceName);
return NULL;
}
#define FILE_COPY_CHUNK 0x01000000
EFI_STATUS
EfiCopyFile (
IN CHAR8 *DestinationFile,
IN CHAR8 *SourceFile
)
{
EFI_OPEN_FILE *Source = NULL;
EFI_OPEN_FILE *Destination = NULL;
EFI_STATUS Status = EFI_SUCCESS;
VOID *Buffer = NULL;
UINTN Size;
UINTN Offset;
UINTN Chunk = FILE_COPY_CHUNK;
Source = EfiOpen(SourceFile, EFI_FILE_MODE_READ, 0);
if (Source == NULL) {
AsciiPrint("Source file open error.\n");
Status = EFI_NOT_FOUND;
goto Exit;
}
Destination = EfiOpen(DestinationFile, EFI_FILE_MODE_WRITE | EFI_FILE_MODE_CREATE, 0);
if (Destination == NULL) {
AsciiPrint("Destination file open error.\n");
Status = EFI_NOT_FOUND;
goto Exit;
}
Buffer = AllocatePool(FILE_COPY_CHUNK);
if (Buffer == NULL) {
Status = EFI_OUT_OF_RESOURCES;
goto Exit;
}
Size = EfiTell(Source, NULL);
for (Offset = 0; Offset + FILE_COPY_CHUNK <= Size; Offset += Chunk) {
Chunk = FILE_COPY_CHUNK;
Status = EfiRead(Source, Buffer, &Chunk);
if (EFI_ERROR(Status)) {
AsciiPrint("Read file error\n");
goto Exit;
}
Status = EfiWrite(Destination, Buffer, &Chunk);
if (EFI_ERROR(Status)) {
AsciiPrint("Write file error\n");
goto Exit;
}
}
// Any left over?
if (Offset < Size) {
Chunk = Size - Offset;
Status = EfiRead(Source, Buffer, &Chunk);
if (EFI_ERROR(Status)) {
AsciiPrint("Read file error\n");
goto Exit;
}
Status = EfiWrite(Destination, Buffer, &Chunk);
if (EFI_ERROR(Status)) {
AsciiPrint("Write file error\n");
goto Exit;
}
}
Exit:
if (Source != NULL) {
Status = EfiClose(Source);
if (EFI_ERROR(Status)) {
AsciiPrint("Source close error");
}
}
if (Destination != NULL) {
Status = EfiClose(Destination);
if (EFI_ERROR(Status)) {
AsciiPrint("Destination close error");
}
}
if (Buffer != NULL) {
FreePool(Buffer);
}
return Status;
}
/**
Use DeviceType and Index to form a valid PathName and try and open it.
@param DeviceType Device type to open
@param Index Device Index to use. Zero relative.
@return NULL Open failed
@return Valid EFI_OPEN_FILE handle
**/
EFI_OPEN_FILE *
EfiDeviceOpenByType (
IN EFI_OPEN_FILE_TYPE DeviceType,
IN UINTN Index
)
{
CHAR8 *DevStr;
CHAR8 Path[MAX_CMD_LINE];
switch (DeviceType) {
case EfiOpenLoadFile:
DevStr = "loadfile%d:";
break;
case EfiOpenFirmwareVolume:
DevStr = "fv%d:";
break;
case EfiOpenFileSystem:
DevStr = "fs%d:";
break;
case EfiOpenBlockIo:
DevStr = "blk%d:";
break;
case EfiOpenMemoryBuffer:
DevStr = "a%d:";
break;
default:
return NULL;
}
AsciiSPrint (Path, MAX_PATHNAME, DevStr, Index);
return EfiOpen (Path, EFI_FILE_MODE_READ, 0);
}
/**
Close a file handle opened by EfiOpen() and free all resources allocated by
EfiOpen().
@param Stream Open File Handle
@return EFI_INVALID_PARAMETER Stream is not an Open File
@return EFI_SUCCESS Steam closed
**/
EFI_STATUS
EfiClose (
IN EFI_OPEN_FILE *File
)
{
EFI_STATUS Status;
UINT64 TftpBufferSize;
if (!FileHandleValid (File)) {
return EFI_INVALID_PARAMETER;
}
//Write the buffer contents to TFTP file.
if ((File->Type == EfiOpenTftp) && (File->IsDirty)) {
TftpBufferSize = File->Size;
Status = EblMtftp (
EFI_PXE_BASE_CODE_TFTP_WRITE_FILE,
File->Buffer,
TRUE,
&TftpBufferSize,
NULL,
&File->ServerIp,
(UINT8 *)File->FileName,
NULL,
FALSE
);
if (EFI_ERROR(Status)) {
AsciiPrint("TFTP error during APPLE_NSP_TFTP_WRITE_FILE: %r\n", Status);
return Status;
}
}
if ((File->Type == EfiOpenLoadFile) ||
((File->Type == EfiOpenTftp) && (File->IsBufferValid == TRUE))) {
EblFreePool(File->Buffer);
}
EblFreePool (File->DevicePath);
EblFreePool (File->DeviceName);
EblFreePool (File->FsFileInfo);
EblFreePool (File->FsInfo);
if (File->FsFileHandle != NULL) {
File->FsFileHandle->Close (File->FsFileHandle);
}
// Need to free File and it's Guard structures
EblFreePool (BASE_CR (File, EFI_OPEN_FILE_GUARD, File));
return EFI_SUCCESS;
}
/**
Return the size of the file represented by Stream. Also return the current
Seek position. Opening a file will enable a valid file size to be returned.
LoadFile is an exception as a load file size is set to zero.
@param Stream Open File Handle
@return 0 Stream is not an Open File or a valid LoadFile handle
**/
UINTN
EfiTell (
IN EFI_OPEN_FILE *File,
OUT EFI_LBA *CurrentPosition OPTIONAL
)
{
EFI_STATUS Status;
UINT64 BufferSize = 0;
if (!FileHandleValid (File)) {
return 0;
}
if (CurrentPosition != NULL) {
*CurrentPosition = File->CurrentPosition;
}
if (File->Type == EfiOpenLoadFile) {
// Figure out the File->Size
File->Buffer = NULL;
File->Size = 0;
Status = File->LoadFile->LoadFile (File->LoadFile, File->DevicePath, FALSE, &File->Size, File->Buffer);
if (Status != EFI_BUFFER_TOO_SMALL) {
return 0;
}
File->MaxPosition = (UINT64)File->Size;
} else if (File->Type == EfiOpenTftp) {
Status = EblMtftp (
EFI_PXE_BASE_CODE_TFTP_GET_FILE_SIZE,
NULL,
FALSE,
&BufferSize,
NULL,
&File->ServerIp,
(UINT8 *)File->FileName,
NULL,
TRUE
);
if (EFI_ERROR(Status)) {
AsciiPrint("TFTP error during APPLE_NSP_TFTP_GET_FILE_SIZE: %r\n", Status);
return 0;
}
File->Size = (UINTN)BufferSize;
File->MaxPosition = File->Size;
}
return File->Size;
}
/**
Seek to the Offset locaiton in the file. LoadFile and FV device types do
not support EfiSeek(). It is not possible to grow the file size using
EfiSeek().
SeekType defines how use Offset to calculate the new file position:
EfiSeekStart : Position = Offset
EfiSeekCurrent: Position is Offset bytes from the current position
EfiSeekEnd : Only supported if Offset is zero to seek to end of file.
@param Stream Open File Handle
@param Offset Offset to seek too.
@param SeekType Type of seek to perform
@return EFI_INVALID_PARAMETER Stream is not an Open File
@return EFI_UNSUPPORTED LoadFile and FV doe not support Seek
@return EFI_NOT_FOUND Seek past the end of the file.
@return EFI_SUCCESS Steam closed
**/
EFI_STATUS
EfiSeek (
IN EFI_OPEN_FILE *File,
IN EFI_LBA Offset,
IN EFI_SEEK_TYPE SeekType
)
{
EFI_STATUS Status;
UINT64 CurrentPosition;
if (!FileHandleValid (File)) {
return EFI_INVALID_PARAMETER;
}
if (File->Type == EfiOpenLoadFile || File->Type == EfiOpenFirmwareVolume) {
// LoadFile and FV do not support Seek
return EFI_UNSUPPORTED;
}
CurrentPosition = File->CurrentPosition;
switch (SeekType) {
case EfiSeekStart:
if (Offset > File->MaxPosition) {
return EFI_NOT_FOUND;
}
CurrentPosition = Offset;
break;
case EfiSeekCurrent:
if ((File->CurrentPosition + Offset) > File->MaxPosition) {
return EFI_NOT_FOUND;
}
CurrentPosition += Offset;
break;
case EfiSeekEnd:
if (Offset != 0) {
// We don't support growing file size via seeking past end of file
return EFI_UNSUPPORTED;
}
CurrentPosition = File->MaxPosition;
break;
default:
return EFI_NOT_FOUND;
}
Status = EFI_SUCCESS;
if (File->FsFileHandle != NULL) {
Status = File->FsFileHandle->SetPosition (File->FsFileHandle, CurrentPosition);
}
if (!EFI_ERROR (Status)) {
File->CurrentPosition = CurrentPosition;
}
return Status;
}
EFI_STATUS
CacheTftpFile (
IN OUT EFI_OPEN_FILE *File
)
{
EFI_STATUS Status;
UINT64 TftpBufferSize;
if (File->IsBufferValid) {
return EFI_SUCCESS;
}
// Make sure the file size is set.
EfiTell (File, NULL);
//Allocate a buffer to hold the whole file.
File->Buffer = AllocatePool(File->Size);
if (File->Buffer == NULL) {
return EFI_OUT_OF_RESOURCES;
}
TftpBufferSize = File->Size;
Status = EblMtftp (
EFI_PXE_BASE_CODE_TFTP_READ_FILE,
File->Buffer,
FALSE,
&TftpBufferSize,
NULL,
&File->ServerIp,
(UINT8 *)File->FileName,
NULL,
FALSE);
if (EFI_ERROR(Status)) {
AsciiPrint("TFTP error during APPLE_NSP_TFTP_READ_FILE: %r\n", Status);
FreePool(File->Buffer);
return Status;
}
// Set the buffer valid flag.
File->IsBufferValid = TRUE;
return Status;
}
/**
Read BufferSize bytes from the current locaiton in the file. For load file,
FV, and TFTP case you must read the entire file.
@param Stream Open File Handle
@param Buffer Caller allocated buffer.
@param BufferSize Size of buffer in bytes.
@return EFI_SUCCESS Stream is not an Open File
@return EFI_END_OF_FILE Tried to read past the end of the file
@return EFI_INVALID_PARAMETER Stream is not an open file handle
@return EFI_BUFFER_TOO_SMALL Buffer is not big enough to do the read
@return "other" Error returned from device read
**/
EFI_STATUS
EfiRead (
IN EFI_OPEN_FILE *File,
OUT VOID *Buffer,
OUT UINTN *BufferSize
)
{
EFI_STATUS Status;
UINT32 AuthenticationStatus;
EFI_DISK_IO_PROTOCOL *DiskIo;
if (!FileHandleValid (File)) {
return EFI_INVALID_PARAMETER;
}
// Don't read past the end of the file.
if ((File->CurrentPosition + *BufferSize) > File->MaxPosition) {
return EFI_END_OF_FILE;
}
switch (File->Type) {
case EfiOpenMemoryBuffer:
CopyMem (Buffer, File->Buffer + File->CurrentPosition, *BufferSize);
File->CurrentPosition += *BufferSize;
Status = EFI_SUCCESS;
break;
case EfiOpenLoadFile:
// Figure out the File->Size
EfiTell (File, NULL);
Status = File->LoadFile->LoadFile (File->LoadFile, File->DevicePath, FALSE, BufferSize, Buffer);
break;
case EfiOpenFirmwareVolume:
if (File->FvSectionType == EFI_SECTION_ALL) {
Status = File->Fv->ReadFile (
File->Fv,
&File->FvNameGuid,
&Buffer,
BufferSize,
&File->FvType,
&File->FvAttributes,
&AuthenticationStatus
);
} else {
Status = File->Fv->ReadSection (
File->Fv,
&File->FvNameGuid,
File->FvSectionType,
0,
&Buffer,
BufferSize,
&AuthenticationStatus
);
}
break;
case EfiOpenFileSystem:
Status = File->FsFileHandle->Read (File->FsFileHandle, BufferSize, Buffer);
File->CurrentPosition += *BufferSize;
break;
case EfiOpenBlockIo:
Status = gBS->HandleProtocol(File->EfiHandle, &gEfiDiskIoProtocolGuid, (VOID **)&DiskIo);
if (!EFI_ERROR(Status)) {
Status = DiskIo->ReadDisk(DiskIo, File->FsBlockIoMedia.MediaId, File->DiskOffset + File->CurrentPosition, *BufferSize, Buffer);
}
File->CurrentPosition += *BufferSize;
break;
case EfiOpenTftp:
// Cache the file if it hasn't been cached yet.
if (File->IsBufferValid == FALSE) {
Status = CacheTftpFile (File);
if (EFI_ERROR (Status)) {
return Status;
}
}
// Copy out the requested data
CopyMem (Buffer, File->Buffer + File->CurrentPosition, *BufferSize);
File->CurrentPosition += *BufferSize;
Status = EFI_SUCCESS;
break;
default:
return EFI_INVALID_PARAMETER;
};
return Status;
}
/**
Read the entire file into a buffer. This routine allocates the buffer and
returns it to the user full of the read data.
This is very useful for load flie where it's hard to know how big the buffer
must be.
@param Stream Open File Handle
@param Buffer Pointer to buffer to return.
@param BufferSize Pointer to Size of buffer return..
@return EFI_SUCCESS Stream is not an Open File
@return EFI_END_OF_FILE Tried to read past the end of the file
@return EFI_INVALID_PARAMETER Stream is not an open file handle
@return EFI_BUFFER_TOO_SMALL Buffer is not big enough to do the read
@return "other" Error returned from device read
**/
EFI_STATUS
EfiReadAllocatePool (
IN EFI_OPEN_FILE *File,
OUT VOID **Buffer,
OUT UINTN *BufferSize
)
{
if (!FileHandleValid (File)) {
return EFI_INVALID_PARAMETER;
}
// Loadfile defers file size determination on Open so use tell to find it
EfiTell (File, NULL);
*BufferSize = File->Size;
*Buffer = AllocatePool (*BufferSize);
if (*Buffer == NULL) {
return EFI_NOT_FOUND;
}
return EfiRead (File, *Buffer, BufferSize);
}
/**
Write data back to the file. For TFTP case you must write the entire file.
@param Stream Open File Handle
@param Buffer Pointer to buffer to return.
@param BufferSize Pointer to Size of buffer return..
@return EFI_SUCCESS Stream is not an Open File
@return EFI_END_OF_FILE Tried to read past the end of the file
@return EFI_INVALID_PARAMETER Stream is not an open file handle
@return EFI_BUFFER_TOO_SMALL Buffer is not big enough to do the read
@return "other" Error returned from device write
**/
EFI_STATUS
EfiWrite (
IN EFI_OPEN_FILE *File,
OUT VOID *Buffer,
OUT UINTN *BufferSize
)
{
EFI_STATUS Status;
EFI_FV_WRITE_FILE_DATA FileData;
EFI_DISK_IO_PROTOCOL *DiskIo;
if (!FileHandleValid (File)) {
return EFI_INVALID_PARAMETER;
}
switch (File->Type) {
case EfiOpenMemoryBuffer:
if ((File->CurrentPosition + *BufferSize) > File->MaxPosition) {
return EFI_END_OF_FILE;
}
CopyMem (File->Buffer + File->CurrentPosition, Buffer, *BufferSize);
File->CurrentPosition += *BufferSize;
Status = EFI_SUCCESS;
case EfiOpenLoadFile:
// LoadFile device is read only be definition
Status = EFI_UNSUPPORTED;
case EfiOpenFirmwareVolume:
if (File->FvSectionType != EFI_SECTION_ALL) {
// Writes not support to a specific section. You have to update entire file
return EFI_UNSUPPORTED;
}
FileData.NameGuid = &(File->FvNameGuid);
FileData.Type = File->FvType;
FileData.FileAttributes = File->FvAttributes;
FileData.Buffer = Buffer;
FileData.BufferSize = (UINT32)*BufferSize;
Status = File->Fv->WriteFile (File->Fv, 1, EFI_FV_UNRELIABLE_WRITE, &FileData);
break;
case EfiOpenFileSystem:
Status = File->FsFileHandle->Write (File->FsFileHandle, BufferSize, Buffer);
File->CurrentPosition += *BufferSize;
break;
case EfiOpenBlockIo:
if ((File->CurrentPosition + *BufferSize) > File->MaxPosition) {
return EFI_END_OF_FILE;
}
Status = gBS->HandleProtocol (File->EfiHandle, &gEfiDiskIoProtocolGuid, (VOID **)&DiskIo);
if (!EFI_ERROR(Status)) {
Status = DiskIo->WriteDisk (DiskIo, File->FsBlockIoMedia.MediaId, File->DiskOffset + File->CurrentPosition, *BufferSize, Buffer);
}
File->CurrentPosition += *BufferSize;
break;
case EfiOpenTftp:
// Cache the file if it hasn't been cached yet.
if (File->IsBufferValid == FALSE) {
Status = CacheTftpFile(File);
if (EFI_ERROR(Status)) {
return Status;
}
}
// Don't overwrite the buffer
if ((File->CurrentPosition + *BufferSize) > File->MaxPosition) {
UINT8 *TempBuffer;
TempBuffer = File->Buffer;
File->Buffer = AllocatePool ((UINTN)(File->CurrentPosition + *BufferSize));
if (File->Buffer == NULL) {
return EFI_OUT_OF_RESOURCES;
}
CopyMem (File->Buffer, TempBuffer, File->Size);
FreePool (TempBuffer);
File->Size = (UINTN)(File->CurrentPosition + *BufferSize);
File->MaxPosition = (UINT64)File->Size;
}
// Copy in the requested data
CopyMem (File->Buffer + File->CurrentPosition, Buffer, *BufferSize);
File->CurrentPosition += *BufferSize;
// Mark the file dirty
File->IsDirty = TRUE;
Status = EFI_SUCCESS;
break;
default:
Status = EFI_INVALID_PARAMETER;
};
return Status;
}
/**
Given Cwd expand Path to remove .. and replace them with real
directory names.
@param Cwd Current Working Directory
@param Path Path to expand
@return NULL Cwd or Path are not valid
@return 'other' Path with .. expanded
**/
CHAR8 *
ExpandPath (
IN CHAR8 *Cwd,
IN CHAR8 *Path
)
{
CHAR8 *NewPath;
CHAR8 *Work, *Start, *End;
UINTN StrLen;
UINTN i;
if (Cwd == NULL || Path == NULL) {
return NULL;
}
StrLen = AsciiStrSize (Cwd);
if (StrLen <= 2) {
// Smallest valid path is 1 char and a null
return NULL;
}
StrLen = AsciiStrSize (Path);
NewPath = AllocatePool (AsciiStrSize (Cwd) + StrLen + 1);
if (NewPath == NULL) {
return NULL;
}
AsciiStrCpy (NewPath, Cwd);
End = Path + StrLen;
for (Start = Path ;;) {
Work = AsciiStrStr (Start, "..") ;
if (Work == NULL) {
// Remaining part of Path contains no more ..
break;
}
// append path prior to ..
AsciiStrnCat (NewPath, Start, Work - Start);
StrLen = AsciiStrLen (NewPath);
for (i = StrLen; i >= 0; i--) {
if (NewPath[i] == ':') {
// too many ..
return NULL;
}
if (NewPath[i] == '/' || NewPath[i] == '\\') {
if ((i > 0) && (NewPath[i-1] == ':')) {
// leave the / before a :
NewPath[i+1] = '\0';
} else {
// replace / will Null to remove trailing file/dir reference
NewPath[i] = '\0';
}
break;
}
}
Start = Work + 3;
}
// Handle the path that remains after the ..
AsciiStrnCat (NewPath, Start, End - Start);
return NewPath;
}
/**
Set the Curent Working Directory (CWD). If a call is made to EfiOpen () and
the path does not contain a device name, The CWD is prepended to the path.
@param Cwd Current Working Directory to set
@return EFI_SUCCESS CWD is set
@return EFI_INVALID_PARAMETER Cwd is not a valid device:path
**/
EFI_STATUS
EfiSetCwd (
IN CHAR8 *Cwd
)
{
EFI_OPEN_FILE *File;
UINTN Len;
CHAR8 *Path;
if (Cwd == NULL) {
return EFI_INVALID_PARAMETER;
}
if (AsciiStrCmp (Cwd, ".") == 0) {
// cd . is a no-op
return EFI_SUCCESS;
}
Path = Cwd;
if (AsciiStrStr (Cwd, "..") != NULL) {
if (gCwd == NULL) {
// no parent
return EFI_SUCCESS;
}
Len = AsciiStrLen (gCwd);
if ((gCwd[Len-2] == ':') && ((gCwd[Len-1] == '/') || (gCwd[Len-1] == '\\'))) {
// parent is device so nothing to do
return EFI_SUCCESS;
}
// Expand .. in Cwd, given we know current working directory
Path = ExpandPath (gCwd, Cwd);
if (Path == NULL) {
return EFI_NOT_FOUND;
}
}
File = EfiOpen (Path, EFI_FILE_MODE_READ, 0);
if (File == NULL) {
return EFI_INVALID_PARAMETER;
}
if (gCwd != NULL) {
FreePool (gCwd);
}
// Use the info returned from EfiOpen as it can add in CWD if needed. So Cwd could be
// relative to the current gCwd or not.
gCwd = AllocatePool (AsciiStrSize (File->DeviceName) + AsciiStrSize (File->FileName) + 1);
if (gCwd == NULL) {
return EFI_INVALID_PARAMETER;
}
AsciiStrCpy (gCwd, File->DeviceName);
if (File->FileName == NULL) {
AsciiStrCat (gCwd, ":\\");
} else {
AsciiStrCat (gCwd, ":");
AsciiStrCat (gCwd, File->FileName);
}
EfiClose (File);
if (Path != Cwd) {
FreePool (Path);
}
return EFI_SUCCESS;
}
/**
Set the Curent Working Directory (CWD). If a call is made to EfiOpen () and
the path does not contain a device name, The CWD is prepended to the path.
The CWD buffer is only valid until a new call is made to EfiSetCwd(). After
a call to EfiSetCwd() it is not legal to use the pointer returned by
this funciton.
@param Cwd Current Working Directory
@return "" No CWD set
@return 'other' Returns buffer that contains CWD.
**/
CHAR8 *
EfiGetCwd (
VOID
)
{
if (gCwd == NULL) {
return "";
}
return gCwd;
}
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