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// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package pipe
import (
"fmt"
"math"
"syscall"
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
"gvisor.googlesource.com/gvisor/pkg/waiter"
)
// ReaderWriter satisfies the FileOperations interface and services both
// read and write requests. This should only be used directly for named pipes.
// pipe(2) and pipe2(2) only support unidirectional pipes and should use
// either pipe.Reader or pipe.Writer.
//
// +stateify savable
type ReaderWriter struct {
fsutil.PipeSeek `state:"nosave"`
fsutil.NotDirReaddir `state:"nosave"`
fsutil.NoFsync `state:"nosave"`
fsutil.NoopFlush `state:"nosave"`
fsutil.NoMMap `state:"nosave"`
*Pipe
}
// Release implements fs.FileOperations.Release.
func (rw *ReaderWriter) Release() {
rw.Pipe.rClose()
rw.Pipe.wClose()
// Wake up readers and writers.
rw.Pipe.Notify(waiter.EventIn | waiter.EventOut)
}
// Read implements fs.FileOperations.Read.
func (rw *ReaderWriter) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, _ int64) (int64, error) {
n, err := rw.Pipe.read(ctx, dst)
if n > 0 {
rw.Pipe.Notify(waiter.EventOut)
}
return n, err
}
// Write implements fs.FileOperations.Write.
func (rw *ReaderWriter) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, _ int64) (int64, error) {
n, err := rw.Pipe.write(ctx, src)
if n > 0 {
rw.Pipe.Notify(waiter.EventIn)
}
return n, err
}
// Readiness returns the ready events in the underlying pipe.
func (rw *ReaderWriter) Readiness(mask waiter.EventMask) waiter.EventMask {
return rw.Pipe.rwReadiness() & mask
}
// Ioctl implements fs.FileOperations.Ioctl.
func (rw *ReaderWriter) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error) {
// Switch on ioctl request.
switch int(args[1].Int()) {
case syscall.TIOCINQ:
v := rw.queuedSize()
if v > math.MaxInt32 {
panic(fmt.Sprintf("Impossibly large pipe queued size: %d", v))
}
// Copy result to user-space.
_, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{
AddressSpaceActive: true,
})
return 0, err
default:
return 0, syscall.ENOTTY
}
}
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