OvmfPkg/BaseMemEncryptSevLib: skip the pre-validated system RAM

[mirror_edk2.git] / OvmfPkg / VirtioFsDxe / FuseLookup.c

/** @file\r
  FUSE_LOOKUP wrapper for the Virtio Filesystem device.\r
\r
  Copyright (C) 2020, Red Hat, Inc.\r
\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
**/\r
\r
#include <Library/BaseLib.h> // AsciiStrSize()\r
\r
#include "VirtioFsDxe.h"\r
\r
/**\r
  Send a FUSE_LOOKUP request to the Virtio Filesystem device, for resolving a\r
  filename to an inode.\r
\r
  The function returns EFI_NOT_FOUND exclusively if the Virtio Filesystem\r
  device explicitly responds with ENOENT -- "No such file or directory".\r
\r
  The function may only be called after VirtioFsFuseInitSession() returns\r
  successfully and before VirtioFsUninit() is called.\r
\r
  @param[in,out] VirtioFs  The Virtio Filesystem device to send the FUSE_LOOKUP\r
                           request to. On output, the FUSE request counter\r
                           "VirtioFs->RequestId" will have been incremented.\r
\r
  @param[in] DirNodeId     The inode number of the directory in which Name\r
                           should be resolved to an inode.\r
\r
  @param[in] Name          The single-component filename to resolve in the\r
                           directory identified by DirNodeId.\r
\r
  @param[out] NodeId       The inode number which Name has been resolved to.\r
\r
  @param[out] FuseAttr     The VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE object\r
                           describing the properties of the resolved inode.\r
\r
  @retval EFI_SUCCESS    Filename to inode resolution successful.\r
\r
  @retval EFI_NOT_FOUND  The Virtio Filesystem device explicitly reported\r
                         ENOENT -- "No such file or directory".\r
\r
  @return                The "errno" value mapped to an EFI_STATUS code, if the\r
                         Virtio Filesystem device explicitly reported an error\r
                         different from ENOENT. If said mapping resulted in\r
                         EFI_NOT_FOUND, it is remapped to EFI_DEVICE_ERROR.\r
\r
  @return                Error codes propagated from VirtioFsSgListsValidate(),\r
                         VirtioFsFuseNewRequest(), VirtioFsSgListsSubmit(),\r
                         VirtioFsFuseCheckResponse(). EFI_NOT_FOUND is remapped\r
                         to EFI_DEVICE_ERROR.\r
**/\r
EFI_STATUS\r
VirtioFsFuseLookup (\r
  IN OUT VIRTIO_FS                        *VirtioFs,\r
  IN     UINT64                           DirNodeId,\r
  IN     CHAR8                            *Name,\r
  OUT UINT64                              *NodeId,\r
  OUT VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE  *FuseAttr\r
  )\r
{\r
  VIRTIO_FS_FUSE_REQUEST         CommonReq;\r
  VIRTIO_FS_IO_VECTOR            ReqIoVec[2];\r
  VIRTIO_FS_SCATTER_GATHER_LIST  ReqSgList;\r
  VIRTIO_FS_FUSE_RESPONSE        CommonResp;\r
  VIRTIO_FS_FUSE_NODE_RESPONSE   NodeResp;\r
  VIRTIO_FS_IO_VECTOR            RespIoVec[3];\r
  VIRTIO_FS_SCATTER_GATHER_LIST  RespSgList;\r
  EFI_STATUS                     Status;\r
\r
  //\r
  // Set up the scatter-gather lists.\r
  //\r
  ReqIoVec[0].Buffer = &CommonReq;\r
  ReqIoVec[0].Size   = sizeof CommonReq;\r
  ReqIoVec[1].Buffer = Name;\r
  ReqIoVec[1].Size   = AsciiStrSize (Name);\r
  ReqSgList.IoVec    = ReqIoVec;\r
  ReqSgList.NumVec   = ARRAY_SIZE (ReqIoVec);\r
\r
  RespIoVec[0].Buffer = &CommonResp;\r
  RespIoVec[0].Size   = sizeof CommonResp;\r
  RespIoVec[1].Buffer = &NodeResp;\r
  RespIoVec[1].Size   = sizeof NodeResp;\r
  RespIoVec[2].Buffer = FuseAttr;\r
  RespIoVec[2].Size   = sizeof *FuseAttr;\r
  RespSgList.IoVec    = RespIoVec;\r
  RespSgList.NumVec   = ARRAY_SIZE (RespIoVec);\r
\r
  //\r
  // Validate the scatter-gather lists; calculate the total transfer sizes.\r
  //\r
  Status = VirtioFsSgListsValidate (VirtioFs, &ReqSgList, &RespSgList);\r
  if (EFI_ERROR (Status)) {\r
    goto Fail;\r
  }\r
\r
  //\r
  // Populate the common request header.\r
  //\r
  Status = VirtioFsFuseNewRequest (\r
             VirtioFs,\r
             &CommonReq,\r
             ReqSgList.TotalSize,\r
             VirtioFsFuseOpLookup,\r
             DirNodeId\r
             );\r
  if (EFI_ERROR (Status)) {\r
    goto Fail;\r
  }\r
\r
  //\r
  // Submit the request.\r
  //\r
  Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);\r
  if (EFI_ERROR (Status)) {\r
    goto Fail;\r
  }\r
\r
  //\r
  // Verify the response (all response buffers are fixed size).\r
  //\r
  Status = VirtioFsFuseCheckResponse (&RespSgList, CommonReq.Unique, NULL);\r
  if (EFI_ERROR (Status)) {\r
    if (Status == EFI_DEVICE_ERROR) {\r
      DEBUG ((\r
        ((CommonResp.Error == VIRTIO_FS_FUSE_ERRNO_ENOENT) ?\r
         DEBUG_VERBOSE :\r
         DEBUG_ERROR),\r
        "%a: Label=\"%s\" DirNodeId=%Lu Name=\"%a\" Errno=%d\n",\r
        __FUNCTION__,\r
        VirtioFs->Label,\r
        DirNodeId,\r
        Name,\r
        CommonResp.Error\r
        ));\r
      if (CommonResp.Error == VIRTIO_FS_FUSE_ERRNO_ENOENT) {\r
        return EFI_NOT_FOUND;\r
      }\r
\r
      Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);\r
    }\r
\r
    goto Fail;\r
  }\r
\r
  //\r
  // Output the NodeId to which Name has been resolved to.\r
  //\r
  *NodeId = NodeResp.NodeId;\r
  return EFI_SUCCESS;\r
\r
Fail:\r
  return (Status == EFI_NOT_FOUND) ? EFI_DEVICE_ERROR : Status;\r
}\r