summaryrefslogtreecommitdiffhomepage
path: root/pkg/sentry/fs/gofer/socket.go
blob: 406756f5f297f3566e228653121b13f4be9d7ae7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
// Copyright 2018 Google Inc.
//
// 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 gofer

import (
	"gvisor.googlesource.com/gvisor/pkg/p9"
	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
	"gvisor.googlesource.com/gvisor/pkg/sentry/fs/host"
	"gvisor.googlesource.com/gvisor/pkg/tcpip"
	"gvisor.googlesource.com/gvisor/pkg/tcpip/transport/unix"
	"gvisor.googlesource.com/gvisor/pkg/waiter"
)

// BoundEndpoint returns a gofer-backed unix.BoundEndpoint.
func (i *inodeOperations) BoundEndpoint(inode *fs.Inode, path string) unix.BoundEndpoint {
	if !fs.IsSocket(i.fileState.sattr) {
		return nil
	}

	if i.session().endpoints != nil {
		ep := i.session().endpoints.get(i.fileState.key)
		if ep != nil {
			return ep
		}

		// Not found in endpoints map, it may be a gofer backed unix socket...
	}

	inode.IncRef()
	return &endpoint{inode, i.fileState.file.file, path}
}

// endpoint is a Gofer-backed unix.BoundEndpoint.
//
// An endpoint's lifetime is the time between when InodeOperations.BoundEndpoint()
// is called and either BoundEndpoint.BidirectionalConnect or
// BoundEndpoint.UnidirectionalConnect is called.
type endpoint struct {
	// inode is the filesystem inode which produced this endpoint.
	inode *fs.Inode

	// file is the p9 file that contains a single unopened fid.
	file p9.File

	// path is the sentry path where this endpoint is bound.
	path string
}

func unixSockToP9(t unix.SockType) (p9.ConnectFlags, bool) {
	switch t {
	case unix.SockStream:
		return p9.StreamSocket, true
	case unix.SockSeqpacket:
		return p9.SeqpacketSocket, true
	case unix.SockDgram:
		return p9.DgramSocket, true
	}
	return 0, false
}

// BidirectionalConnect implements ConnectableEndpoint.BidirectionalConnect.
func (e *endpoint) BidirectionalConnect(ce unix.ConnectingEndpoint, returnConnect func(unix.Receiver, unix.ConnectedEndpoint)) *tcpip.Error {
	cf, ok := unixSockToP9(ce.Type())
	if !ok {
		return tcpip.ErrConnectionRefused
	}

	// No lock ordering required as only the ConnectingEndpoint has a mutex.
	ce.Lock()

	// Check connecting state.
	if ce.Connected() {
		ce.Unlock()
		return tcpip.ErrAlreadyConnected
	}
	if ce.Listening() {
		ce.Unlock()
		return tcpip.ErrInvalidEndpointState
	}

	hostFile, err := e.file.Connect(cf)
	if err != nil {
		ce.Unlock()
		return tcpip.ErrConnectionRefused
	}

	c, terr := host.NewConnectedEndpoint(hostFile, ce.WaiterQueue(), e.path)
	if terr != nil {
		ce.Unlock()
		return terr
	}

	returnConnect(c, c)
	ce.Unlock()
	c.Init()

	return nil
}

// UnidirectionalConnect implements unix.BoundEndpoint.UnidirectionalConnect.
func (e *endpoint) UnidirectionalConnect() (unix.ConnectedEndpoint, *tcpip.Error) {
	hostFile, err := e.file.Connect(p9.DgramSocket)
	if err != nil {
		return nil, tcpip.ErrConnectionRefused
	}

	c, terr := host.NewConnectedEndpoint(hostFile, &waiter.Queue{}, e.path)
	if terr != nil {
		return nil, terr
	}
	c.Init()

	// We don't need the receiver.
	c.CloseRecv()
	c.Release()

	return c, nil
}

// Release implements unix.BoundEndpoint.Release.
func (e *endpoint) Release() {
	e.inode.DecRef()
}