github.com/ttpreport/gvisor-ligolo@v0.0.0-20240123134145-a858404967ba/pkg/sentry/devices/memdev/full.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 memdev
    16  
    17  import (
    18  	"github.com/ttpreport/gvisor-ligolo/pkg/context"
    19  	"github.com/ttpreport/gvisor-ligolo/pkg/errors/linuxerr"
    20  	"github.com/ttpreport/gvisor-ligolo/pkg/sentry/vfs"
    21  	"github.com/ttpreport/gvisor-ligolo/pkg/usermem"
    22  )
    23  
    24  const fullDevMinor = 7
    25  
    26  // fullDevice implements vfs.Device for /dev/full.
    27  //
    28  // +stateify savable
    29  type fullDevice struct{}
    30  
    31  // Open implements vfs.Device.Open.
    32  func (fullDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
    33  	fd := &fullFD{}
    34  	if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
    35  		UseDentryMetadata: true,
    36  	}); err != nil {
    37  		return nil, err
    38  	}
    39  	return &fd.vfsfd, nil
    40  }
    41  
    42  // fullFD implements vfs.FileDescriptionImpl for /dev/full.
    43  //
    44  // +stateify savable
    45  type fullFD struct {
    46  	vfsfd vfs.FileDescription
    47  	vfs.FileDescriptionDefaultImpl
    48  	vfs.DentryMetadataFileDescriptionImpl
    49  	vfs.NoLockFD
    50  }
    51  
    52  // Release implements vfs.FileDescriptionImpl.Release.
    53  func (fd *fullFD) Release(context.Context) {
    54  	// noop
    55  }
    56  
    57  // PRead implements vfs.FileDescriptionImpl.PRead.
    58  func (fd *fullFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
    59  	return dst.ZeroOut(ctx, dst.NumBytes())
    60  }
    61  
    62  // Read implements vfs.FileDescriptionImpl.Read.
    63  func (fd *fullFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
    64  	return dst.ZeroOut(ctx, dst.NumBytes())
    65  }
    66  
    67  // PWrite implements vfs.FileDescriptionImpl.PWrite.
    68  func (fd *fullFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
    69  	return 0, linuxerr.ENOSPC
    70  }
    71  
    72  // Write implements vfs.FileDescriptionImpl.Write.
    73  func (fd *fullFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
    74  	return 0, linuxerr.ENOSPC
    75  }
    76  
    77  // Seek implements vfs.FileDescriptionImpl.Seek.
    78  func (fd *fullFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
    79  	return 0, nil
    80  }