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// Copyright 2018 The gVisor Authors.
//
// 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 unix
import (
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/safemem"
"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
"gvisor.dev/gvisor/pkg/tcpip"
)
// EndpointWriter implements safemem.Writer that writes to a transport.Endpoint.
//
// EndpointWriter is not thread-safe.
type EndpointWriter struct {
Ctx context.Context
// Endpoint is the transport.Endpoint to write to.
Endpoint transport.Endpoint
// Control is the control messages to send.
Control transport.ControlMessages
// To is the endpoint to send to. May be nil.
To transport.BoundEndpoint
}
// WriteFromBlocks implements safemem.Writer.WriteFromBlocks.
func (w *EndpointWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error) {
return safemem.FromVecWriterFunc{func(bufs [][]byte) (int64, error) {
n, err := w.Endpoint.SendMsg(w.Ctx, bufs, w.Control, w.To)
if err != nil {
return int64(n), err.ToError()
}
return int64(n), nil
}}.WriteFromBlocks(srcs)
}
// EndpointReader implements safemem.Reader that reads from a
// transport.Endpoint.
//
// EndpointReader is not thread-safe.
type EndpointReader struct {
Ctx context.Context
// Endpoint is the transport.Endpoint to read from.
Endpoint transport.Endpoint
// Creds indicates if credential control messages are requested.
Creds bool
// NumRights is the number of SCM_RIGHTS FDs requested.
NumRights int
// Peek indicates that the data should not be consumed from the
// endpoint.
Peek bool
// MsgSize is the size of the message that was read from. For stream
// sockets, it is the amount read.
MsgSize int64
// From, if not nil, will be set with the address read from.
From *tcpip.FullAddress
// Control contains the received control messages.
Control transport.ControlMessages
// ControlTrunc indicates that SCM_RIGHTS FDs were discarded based on
// the value of NumRights.
ControlTrunc bool
}
// Truncate calls RecvMsg on the endpoint without writing to a destination.
func (r *EndpointReader) Truncate() error {
// Ignore bytes read since it will always be zero.
_, ms, c, ct, err := r.Endpoint.RecvMsg(r.Ctx, [][]byte{}, r.Creds, r.NumRights, r.Peek, r.From)
r.Control = c
r.ControlTrunc = ct
r.MsgSize = ms
if err != nil {
return err.ToError()
}
return nil
}
// ReadToBlocks implements safemem.Reader.ReadToBlocks.
func (r *EndpointReader) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
return safemem.FromVecReaderFunc{func(bufs [][]byte) (int64, error) {
n, ms, c, ct, err := r.Endpoint.RecvMsg(r.Ctx, bufs, r.Creds, r.NumRights, r.Peek, r.From)
r.Control = c
r.ControlTrunc = ct
r.MsgSize = ms
if err != nil {
return int64(n), err.ToError()
}
return int64(n), nil
}}.ReadToBlocks(dsts)
}
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