github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/kernel/pipe/writer.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 pipe
    16  
    17  import (
    18  	"github.com/SagerNet/gvisor/pkg/context"
    19  	"github.com/SagerNet/gvisor/pkg/waiter"
    20  )
    21  
    22  // Writer satisfies the fs.FileOperations interface for write-only pipes.
    23  // Writer should be used with !fs.FileFlags.Read to reject reads.
    24  //
    25  // +stateify savable
    26  type Writer struct {
    27  	ReaderWriter
    28  }
    29  
    30  // Release implements fs.FileOperations.Release.
    31  //
    32  // This overrides ReaderWriter.Release.
    33  func (w *Writer) Release(context.Context) {
    34  	w.Pipe.wClose()
    35  
    36  	// Wake up readers.
    37  	w.Pipe.Notify(waiter.EventHUp)
    38  }
    39  
    40  // Readiness returns the ready events in the underlying pipe.
    41  func (w *Writer) Readiness(mask waiter.EventMask) waiter.EventMask {
    42  	return w.Pipe.wReadiness() & mask
    43  }