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 unix

     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)(cmsgData(h))) = *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 	ucred := *(*Ucred)(unsafe.Pointer(&m.Data[0]))

    35 	return &ucred, nil

    36 }