EFI_STATUS
FileSetPosition (
IN EFI_FILE *File,
IN UINT64 Position
)
{
SEMIHOST_FCB *Fcb = NULL;
UINTN Length;
EFI_STATUS Status;
Fcb = SEMIHOST_FCB_FROM_THIS(File);
if (!Fcb->IsRoot) {
Status = SemihostFileLength (Fcb->SemihostHandle, &Length);
if (!EFI_ERROR(Status) && (Length < Position)) {
Position = Length;
}
Status = SemihostFileSeek (Fcb->SemihostHandle, (UINT32)Position);
if (!EFI_ERROR(Status)) {
Fcb->Position = Position;
}
} else {
Fcb->Position = Position;
Status = EFI_SUCCESS;
}
return Status;
}
/**
Worker function that extends the size of an open file.
The extension is filled with zeros.
@param[in] Fcb Internal description of the opened file
@param[in] Size The number of bytes, the file has to be extended.
@retval EFI_SUCCESS The file was extended.
@retval EFI_DEVICE_ERROR The last issued semi-hosting operation failed.
**/
STATIC
EFI_STATUS
ExtendFile (
IN SEMIHOST_FCB *Fcb,
IN UINTN Size
)
{
RETURN_STATUS Return;
UINTN Remaining;
CHAR8 WriteBuffer[128];
UINTN WriteNb;
UINTN WriteSize;
Return = SemihostFileSeek (Fcb->SemihostHandle, Fcb->Info.FileSize);
if (RETURN_ERROR (Return)) {
return EFI_DEVICE_ERROR;
}
Remaining = Size;
SetMem (WriteBuffer, 0, sizeof(WriteBuffer));
while (Remaining > 0) {
WriteNb = MIN (Remaining, sizeof(WriteBuffer));
WriteSize = WriteNb;
Return = SemihostFileWrite (Fcb->SemihostHandle, &WriteSize, WriteBuffer);
if (RETURN_ERROR (Return)) {
return EFI_DEVICE_ERROR;
}
Remaining -= WriteNb;
}
return EFI_SUCCESS;
}
/**
Set a file's current position.
@param[in] This A pointer to the EFI_FILE_PROTOCOL instance that is
the file handle to set the requested position on.
@param[in] Position The byte position from the start of the file to set.
@retval EFI_SUCCESS The position was set.
@retval EFI_DEVICE_ERROR The semi-hosting positionning operation failed.
@retval EFI_UNSUPPORTED The seek request for nonzero is not valid on open
directories.
@retval EFI_INVALID_PARAMETER The parameter "This" is NULL.
**/
EFI_STATUS
FileSetPosition (
IN EFI_FILE *This,
IN UINT64 Position
)
{
SEMIHOST_FCB *Fcb;
RETURN_STATUS Return;
if (This == NULL) {
return EFI_INVALID_PARAMETER;
}
Fcb = SEMIHOST_FCB_FROM_THIS (This);
if (Fcb->IsRoot) {
if (Position != 0) {
return EFI_UNSUPPORTED;
}
}
else {
//
// UEFI Spec section 12.5:
// "Seeking to position 0xFFFFFFFFFFFFFFFF causes the current position to
// be set to the end of the file."
//
if (Position == 0xFFFFFFFFFFFFFFFF) {
Position = Fcb->Info.FileSize;
}
Return = SemihostFileSeek (Fcb->SemihostHandle, MIN (Position, Fcb->Info.FileSize));
if (RETURN_ERROR (Return)) {
return EFI_DEVICE_ERROR;
}
}
Fcb->Position = Position;
return EFI_SUCCESS;
}
