Implement new syscall package.

Calls to library functions now use entersyscall and
exitsyscall as appropriate.  This is a first step toward
multiplexing goroutines onto threads.

From-SVN: r180345

1 files changed, 38 insertions, 0 deletions

diff --git a/libgo/go/syscall/sockcmsg_linux.go b/libgo/go/syscall/sockcmsg_linux.go
new file mode 100644
index 0000000..b025ca5
--- /dev/null
+++ b/libgo/go/syscall/sockcmsg_linux.go
@@ -0,0 +1,38 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Socket control messages
+
+package syscall
+
+import (
+	"unsafe"
+)
+
+// UnixCredentials encodes credentials into a socket control message
+// for sending to another process. This can be used for
+// authentication.
+func UnixCredentials(ucred *Ucred) []byte {
+	buf := make([]byte, CmsgSpace(SizeofUcred))
+	cmsg := (*Cmsghdr)(unsafe.Pointer(&buf[0]))
+	cmsg.Level = SOL_SOCKET
+	cmsg.Type = SCM_CREDENTIALS
+	cmsg.SetLen(CmsgLen(SizeofUcred))
+	*((*Ucred)(cmsgData(cmsg))) = *ucred
+	return buf
+}
+
+// ParseUnixCredentials decodes a socket control message that contains
+// credentials in a Ucred structure. To receive such a message, the
+// SO_PASSCRED option must be enabled on the socket.
+func ParseUnixCredentials(msg *SocketControlMessage) (*Ucred, int) {
+	if msg.Header.Level != SOL_SOCKET {
+		return nil, EINVAL
+	}
+	if msg.Header.Type != SCM_CREDENTIALS {
+		return nil, EINVAL
+	}
+	ucred := *(*Ucred)(unsafe.Pointer(&msg.Data[0]))
+	return &ucred, 0
+}