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 (
  83              VirtioFs,
  84              &CommonReq,
  85              ReqSgList.TotalSize,
  86              VirtioFsFuseOpOpenDir,
  87              NodeId
  88              );
  89   if (EFI_ERROR (Status)) {
  90     return Status;
  91   }
  92
  93   //
  94   // Populate the FUSE_OPENDIR-specific fields.
  95   //
  96   OpenReq.Flags  = 0;
  97   OpenReq.Unused = 0;
  98
  99   //
 100   // Submit the request.
 101   //
 102   Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);
 103   if (EFI_ERROR (Status)) {
 104     return Status;
 105   }
 106
 107   //
 108   // Verify the response (all response buffers are fixed size).
 109   //
 110   Status = VirtioFsFuseCheckResponse (&RespSgList, CommonReq.Unique, NULL);
 111   if (EFI_ERROR (Status)) {
 112     if (Status == EFI_DEVICE_ERROR) {
 113       DEBUG ((
 114         DEBUG_ERROR,
 115         "%a: Label=\"%s\" NodeId=%Lu Errno=%d\n",
 116         __FUNCTION__,
 117         VirtioFs->Label,
 118         NodeId,
 119         CommonResp.Error
 120         ));
 121       Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);
 122     }
 123
 124     return Status;
 125   }
 126
 127   //
 128   // Output the open file handle.
 129   //
 130   *FuseHandle = OpenResp.FileHandle;
 131   return EFI_SUCCESS;
 132 }