FuseRead.c

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#include "VirtioFsDxe.h"
 
EFI_STATUS
VirtioFsFuseReadFileOrDir (
  IN OUT VIRTIO_FS  *VirtioFs,
  IN     UINT64     NodeId,
  IN     UINT64     FuseHandle,
  IN     BOOLEAN    IsDir,
  IN     UINT64     Offset,
  IN OUT UINT32     *Size,
  OUT VOID          *Data
  )
{
  VIRTIO_FS_FUSE_REQUEST         CommonReq;
  VIRTIO_FS_FUSE_READ_REQUEST    ReadReq;
  VIRTIO_FS_IO_VECTOR            ReqIoVec[2];
  VIRTIO_FS_SCATTER_GATHER_LIST  ReqSgList;
  VIRTIO_FS_FUSE_RESPONSE        CommonResp;
  VIRTIO_FS_IO_VECTOR            RespIoVec[2];
  VIRTIO_FS_SCATTER_GATHER_LIST  RespSgList;
  EFI_STATUS                     Status;
  UINTN                          TailBufferFill;
 
  //
  // Set up the scatter-gather lists.
  //
  ReqIoVec[0].Buffer = &CommonReq;
  ReqIoVec[0].Size   = sizeof CommonReq;
  ReqIoVec[1].Buffer = &ReadReq;
  ReqIoVec[1].Size   = sizeof ReadReq;
  ReqSgList.IoVec    = ReqIoVec;
  ReqSgList.NumVec   = ARRAY_SIZE (ReqIoVec);
 
  RespIoVec[0].Buffer = &CommonResp;
  RespIoVec[0].Size   = sizeof CommonResp;
  RespIoVec[1].Buffer = Data;
  RespIoVec[1].Size   = *Size;
  RespSgList.IoVec    = RespIoVec;
  RespSgList.NumVec   = ARRAY_SIZE (RespIoVec);
 
  //
  // Validate the scatter-gather lists; calculate the total transfer sizes.
  //
  Status = VirtioFsSgListsValidate (VirtioFs, &ReqSgList, &RespSgList);
  if (EFI_ERROR (Status)) {
    return Status;
  }
 
  //
  // Populate the common request header.
  //
  Status = VirtioFsFuseNewRequest (
             VirtioFs,
             &CommonReq,
             ReqSgList.TotalSize,
             IsDir ? VirtioFsFuseOpReadDirPlus : VirtioFsFuseOpRead,
             NodeId
             );
  if (EFI_ERROR (Status)) {
    return Status;
  }
 
  //
  // Populate the FUSE_READ- / FUSE_READDIRPLUS-specific fields.
  //
  ReadReq.FileHandle = FuseHandle;
  ReadReq.Offset     = Offset;
  ReadReq.Size       = *Size;
  ReadReq.ReadFlags  = 0;
  ReadReq.LockOwner  = 0;
  ReadReq.Flags      = 0;
  ReadReq.Padding    = 0;
 
  //
  // Submit the request.
  //
  Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);
  if (EFI_ERROR (Status)) {
    return Status;
  }
 
  //
  // Verify the response. Note that TailBufferFill is variable.
  //
  Status = VirtioFsFuseCheckResponse (
             &RespSgList,
             CommonReq.Unique,
             &TailBufferFill
             );
  if (EFI_ERROR (Status)) {
    if (Status == EFI_DEVICE_ERROR) {
      DEBUG ((
        DEBUG_ERROR,
        "%a: Label=\"%s\" NodeId=%Lu FuseHandle=%Lu "
        "IsDir=%d Offset=0x%Lx Size=0x%x Data@%p Errno=%d\n",
        __func__,
        VirtioFs->Label,
        NodeId,
        FuseHandle,
        IsDir,
        Offset,
        *Size,
        Data,
        CommonResp.Error
        ));
      Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);
    }
 
    return Status;
  }
 
  //
  // Report the actual transfer size.
  //
  // Integer overflow in the (UINT32) cast below is not possible; the
  // VIRTIO_FS_SCATTER_GATHER_LIST functions would have caught that.
  //
  *Size = (UINT32)TailBufferFill;
  return EFI_SUCCESS;
}