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