OvmfPkg/VirtioFsDxe/FuseGetAttr.c

   1 /** @file
   2   FUSE_GETATTR 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_GETATTR request to the Virtio Filesystem device, for fetching the
  13   attributes of an inode.
  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_GETATTR request to. On output, the FUSE request
  20                            counter "VirtioFs->RequestId" will have been
  21                            incremented.
  22
  23   @param[in] NodeId        The inode number for which the attributes should be
  24                            retrieved.
  25
  26   @param[out] FuseAttr     The VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE object
  27                            describing the properties of the inode.
  28
  29   @retval EFI_SUCCESS  FuseAttr has been filled in.
  30
  31   @return              The "errno" value mapped to an EFI_STATUS code, if the
  32                        Virtio Filesystem device explicitly reported an error.
  33
  34   @return              Error codes propagated from VirtioFsSgListsValidate(),
  35                        VirtioFsFuseNewRequest(), VirtioFsSgListsSubmit(),
  36                        VirtioFsFuseCheckResponse().
  37 **/
  38 EFI_STATUS
  39 VirtioFsFuseGetAttr (
  40   IN OUT VIRTIO_FS                        *VirtioFs,
  41   IN     UINT64                           NodeId,
  42   OUT VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE  *FuseAttr
  43   )
  44 {
  45   VIRTIO_FS_FUSE_REQUEST           CommonReq;
  46   VIRTIO_FS_FUSE_GETATTR_REQUEST   GetAttrReq;
  47   VIRTIO_FS_IO_VECTOR              ReqIoVec[2];
  48   VIRTIO_FS_SCATTER_GATHER_LIST    ReqSgList;
  49   VIRTIO_FS_FUSE_RESPONSE          CommonResp;
  50   VIRTIO_FS_FUSE_GETATTR_RESPONSE  GetAttrResp;
  51   VIRTIO_FS_IO_VECTOR              RespIoVec[3];
  52   VIRTIO_FS_SCATTER_GATHER_LIST    RespSgList;
  53   EFI_STATUS                       Status;
  54
  55   //
  56   // Set up the scatter-gather lists.
  57   //
  58   ReqIoVec[0].Buffer = &CommonReq;
  59   ReqIoVec[0].Size   = sizeof CommonReq;
  60   ReqIoVec[1].Buffer = &GetAttrReq;
  61   ReqIoVec[1].Size   = sizeof GetAttrReq;
  62   ReqSgList.IoVec    = ReqIoVec;
  63   ReqSgList.NumVec   = ARRAY_SIZE (ReqIoVec);
  64
  65   RespIoVec[0].Buffer = &CommonResp;
  66   RespIoVec[0].Size   = sizeof CommonResp;
  67   RespIoVec[1].Buffer = &GetAttrResp;
  68   RespIoVec[1].Size   = sizeof GetAttrResp;
  69   RespIoVec[2].Buffer = FuseAttr;
  70   RespIoVec[2].Size   = sizeof *FuseAttr;
  71   RespSgList.IoVec    = RespIoVec;
  72   RespSgList.NumVec   = ARRAY_SIZE (RespIoVec);
  73
  74   //
  75   // Validate the scatter-gather lists; calculate the total transfer sizes.
  76   //
  77   Status = VirtioFsSgListsValidate (VirtioFs, &ReqSgList, &RespSgList);
  78   if (EFI_ERROR (Status)) {
  79     return Status;
  80   }
  81
  82   //
  83   // Populate the common request header.
  84   //
  85   Status = VirtioFsFuseNewRequest (
  86              VirtioFs,
  87              &CommonReq,
  88              ReqSgList.TotalSize,
  89              VirtioFsFuseOpGetAttr,
  90              NodeId
  91              );
  92   if (EFI_ERROR (Status)) {
  93     return Status;
  94   }
  95
  96   //
  97   // Populate the FUSE_GETATTR-specific fields.
  98   //
  99   GetAttrReq.GetAttrFlags = 0;
 100   GetAttrReq.Dummy        = 0;
 101   GetAttrReq.FileHandle   = 0;
 102
 103   //
 104   // Submit the request.
 105   //
 106   Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);
 107   if (EFI_ERROR (Status)) {
 108     return Status;
 109   }
 110
 111   //
 112   // Verify the response (all response buffers are fixed size).
 113   //
 114   Status = VirtioFsFuseCheckResponse (&RespSgList, CommonReq.Unique, NULL);
 115   if (Status == EFI_DEVICE_ERROR) {
 116     DEBUG ((
 117       DEBUG_ERROR,
 118       "%a: Label=\"%s\" NodeId=%Lu Errno=%d\n",
 119       __FUNCTION__,
 120       VirtioFs->Label,
 121       NodeId,
 122       CommonResp.Error
 123       ));
 124     Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);
 125   }
 126
 127   return Status;
 128 }