OvmfPkg/VirtioFsDxe/FuseOpenDir.c

   1 /** @file
   2   FUSE_OPENDIR wrapper for the Virtio Filesystem device.
   3
   4   Copyright (C) 2020, Red Hat, Inc.
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7 **/
   8
   9 #include "VirtioFsDxe.h"
  10
  11 /**
  12   Send a FUSE_OPENDIR request to the Virtio Filesystem device, for opening a
  13   directory.
  14
  15   The function may only be called after VirtioFsFuseInitSession() returns
  16   successfully and before VirtioFsUninit() is called.
  17
  18   @param[in,out] VirtioFs  The Virtio Filesystem device to send the
  19                            FUSE_OPENDIR request to. On output, the FUSE request
  20                            counter "VirtioFs->RequestId" will have been
  21                            incremented.
  22
  23   @param[in] NodeId        The inode number of the directory to open.
  24
  25   @param[out] FuseHandle   The open file handle returned by the Virtio
  26                            Filesystem device.
  27
  28   @retval EFI_SUCCESS  The directory has been opened.
  29
  30   @return              The "errno" value mapped to an EFI_STATUS code, if the
  31                        Virtio Filesystem device explicitly reported an error.
  32
  33   @return              Error codes propagated from VirtioFsSgListsValidate(),
  34                        VirtioFsFuseNewRequest(), VirtioFsSgListsSubmit(),
  35                        VirtioFsFuseCheckResponse().
  36 **/
  37 EFI_STATUS
  38 VirtioFsFuseOpenDir (
  39   IN OUT VIRTIO_FS *VirtioFs,
  40   IN     UINT64    NodeId,
  41      OUT UINT64    *FuseHandle
  42   )
  43 {
  44   VIRTIO_FS_FUSE_REQUEST        CommonReq;
  45   VIRTIO_FS_FUSE_OPEN_REQUEST   OpenReq;
  46   VIRTIO_FS_IO_VECTOR           ReqIoVec[2];
  47   VIRTIO_FS_SCATTER_GATHER_LIST ReqSgList;
  48   VIRTIO_FS_FUSE_RESPONSE       CommonResp;
  49   VIRTIO_FS_FUSE_OPEN_RESPONSE  OpenResp;
  50   VIRTIO_FS_IO_VECTOR           RespIoVec[2];
  51   VIRTIO_FS_SCATTER_GATHER_LIST RespSgList;
  52   EFI_STATUS                    Status;
  53
  54   //
  55   // Set up the scatter-gather lists.
  56   //
  57   ReqIoVec[0].Buffer = &CommonReq;
  58   ReqIoVec[0].Size   = sizeof CommonReq;
  59   ReqIoVec[1].Buffer = &OpenReq;
  60   ReqIoVec[1].Size   = sizeof OpenReq;
  61   ReqSgList.IoVec    = ReqIoVec;
  62   ReqSgList.NumVec   = ARRAY_SIZE (ReqIoVec);
  63
  64   RespIoVec[0].Buffer = &CommonResp;
  65   RespIoVec[0].Size   = sizeof CommonResp;
  66   RespIoVec[1].Buffer = &OpenResp;
  67   RespIoVec[1].Size   = sizeof OpenResp;
  68   RespSgList.IoVec    = RespIoVec;
  69   RespSgList.NumVec   = ARRAY_SIZE (RespIoVec);
  70
  71   //
  72   // Validate the scatter-gather lists; calculate the total transfer sizes.
  73   //
  74   Status = VirtioFsSgListsValidate (VirtioFs, &ReqSgList, &RespSgList);
  75   if (EFI_ERROR (Status)) {
  76     return Status;
  77   }
  78
  79   //
  80   // Populate the common request header.
  81   //
  82   Status = VirtioFsFuseNewRequest (VirtioFs, &CommonReq, ReqSgList.TotalSize,
  83              VirtioFsFuseOpOpenDir, NodeId);
  84   if (EFI_ERROR (Status)) {
  85     return Status;
  86   }
  87
  88   //
  89   // Populate the FUSE_OPENDIR-specific fields.
  90   //
  91   OpenReq.Flags  = 0;
  92   OpenReq.Unused = 0;
  93
  94   //
  95   // Submit the request.
  96   //
  97   Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);
  98   if (EFI_ERROR (Status)) {
  99     return Status;
 100   }
 101
 102   //
 103   // Verify the response (all response buffers are fixed size).
 104   //
 105   Status = VirtioFsFuseCheckResponse (&RespSgList, CommonReq.Unique, NULL);
 106   if (EFI_ERROR (Status)) {
 107     if (Status == EFI_DEVICE_ERROR) {
 108       DEBUG ((DEBUG_ERROR, "%a: Label=\"%s\" NodeId=%Lu Errno=%d\n",
 109         __FUNCTION__, VirtioFs->Label, NodeId, CommonResp.Error));
 110       Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);
 111     }
 112     return Status;
 113   }
 114
 115   //
 116   // Output the open file handle.
 117   //
 118   *FuseHandle = OpenResp.FileHandle;
 119   return EFI_SUCCESS;
 120 }