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

     1  // Copyright 2018 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 tmpfs
    16  
    17  import (
    18  	"github.com/SagerNet/gvisor/pkg/context"
    19  	"github.com/SagerNet/gvisor/pkg/sentry/fs"
    20  	"github.com/SagerNet/gvisor/pkg/sentry/fs/fsutil"
    21  	"github.com/SagerNet/gvisor/pkg/sentry/memmap"
    22  	"github.com/SagerNet/gvisor/pkg/usermem"
    23  	"github.com/SagerNet/gvisor/pkg/waiter"
    24  )
    25  
    26  // regularFileOperations implements fs.FileOperations for a regular
    27  // tmpfs file.
    28  //
    29  // +stateify savable
    30  type regularFileOperations struct {
    31  	fsutil.FileNoopRelease          `state:"nosave"`
    32  	fsutil.FileGenericSeek          `state:"nosave"`
    33  	fsutil.FileNotDirReaddir        `state:"nosave"`
    34  	fsutil.FileNoopFsync            `state:"nosave"`
    35  	fsutil.FileNoopFlush            `state:"nosave"`
    36  	fsutil.FileNoIoctl              `state:"nosave"`
    37  	fsutil.FileNoSplice             `state:"nosave"`
    38  	fsutil.FileUseInodeUnstableAttr `state:"nosave"`
    39  	waiter.AlwaysReady              `state:"nosave"`
    40  
    41  	// iops is the InodeOperations of a regular tmpfs file. It is
    42  	// guaranteed to be the same as file.Dirent.Inode.InodeOperations,
    43  	// see operations that take fs.File below.
    44  	iops *fileInodeOperations
    45  }
    46  
    47  // Read implements fs.FileOperations.Read.
    48  func (r *regularFileOperations) Read(ctx context.Context, file *fs.File, dst usermem.IOSequence, offset int64) (int64, error) {
    49  	return r.iops.read(ctx, file, dst, offset)
    50  }
    51  
    52  // Write implements fs.FileOperations.Write.
    53  func (r *regularFileOperations) Write(ctx context.Context, file *fs.File, src usermem.IOSequence, offset int64) (int64, error) {
    54  	return r.iops.write(ctx, src, offset)
    55  }
    56  
    57  // ConfigureMMap implements fs.FileOperations.ConfigureMMap.
    58  func (r *regularFileOperations) ConfigureMMap(ctx context.Context, file *fs.File, opts *memmap.MMapOpts) error {
    59  	return fsutil.GenericConfigureMMap(file, r.iops, opts)
    60  }