github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/fs/host/host.go (about)

     1  // Copyright 2020 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package host supports file descriptors imported directly.
    16  package host
    17  
    18  import (
    19  	"github.com/SagerNet/gvisor/pkg/context"
    20  	"github.com/SagerNet/gvisor/pkg/errors/linuxerr"
    21  	"github.com/SagerNet/gvisor/pkg/sentry/fs"
    22  )
    23  
    24  // filesystem is a host filesystem.
    25  //
    26  // +stateify savable
    27  type filesystem struct{}
    28  
    29  func init() {
    30  	fs.RegisterFilesystem(&filesystem{})
    31  }
    32  
    33  // FilesystemName is the name under which the filesystem is registered.
    34  const FilesystemName = "host"
    35  
    36  // Name is the name of the filesystem.
    37  func (*filesystem) Name() string {
    38  	return FilesystemName
    39  }
    40  
    41  // Mount returns an error. Mounting hostfs is not allowed.
    42  func (*filesystem) Mount(ctx context.Context, device string, flags fs.MountSourceFlags, data string, dataObj interface{}) (*fs.Inode, error) {
    43  	return nil, linuxerr.EPERM
    44  }
    45  
    46  // AllowUserMount prohibits users from using mount(2) with this file system.
    47  func (*filesystem) AllowUserMount() bool {
    48  	return false
    49  }
    50  
    51  // AllowUserList prohibits this filesystem to be listed in /proc/filesystems.
    52  func (*filesystem) AllowUserList() bool {
    53  	return false
    54  }
    55  
    56  // Flags returns that there is nothing special about this file system.
    57  func (*filesystem) Flags() fs.FilesystemFlags {
    58  	return 0
    59  }