1 // Copyright 2011 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4 5 // Socket control messages
6 7 package syscall
8 9 import "unsafe"
10 11 // UnixCredentials encodes credentials into a socket control message
12 // for sending to another process. This can be used for
13 // authentication.
14 func UnixCredentials(ucred *Ucred) []byte {
15 b := make([]byte, CmsgSpace(SizeofUcred))
16 h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
17 h.Level = SOL_SOCKET
18 h.Type = SCM_CREDENTIALS
19 h.SetLen(CmsgLen(SizeofUcred))
20 *(*Ucred)(h.data(0)) = *ucred
21 return b
22 }
23 24 // ParseUnixCredentials decodes a socket control message that contains
25 // credentials in a Ucred structure. To receive such a message, the
26 // SO_PASSCRED option must be enabled on the socket.
27 func ParseUnixCredentials(m *SocketControlMessage) (*Ucred, error) {
28 if m.Header.Level != SOL_SOCKET {
29 return nil, EINVAL
30 }
31 if m.Header.Type != SCM_CREDENTIALS {
32 return nil, EINVAL
33 }
34 if uintptr(len(m.Data)) < unsafe.Sizeof(Ucred{}) {
35 return nil, EINVAL
36 }
37 ucred := *(*Ucred)(unsafe.Pointer(&m.Data[0]))
38 return &ucred, nil
39 }
40