Implement a LOCAL_PEERCRED socket option which returns a

`struct xucred` with the credentials of the connected peer.
Obviously this only works (and makes sense) on SOCK_STREAM
sockets.  This works for both the connect(2) and listen(2)
callers.

There is precise documentation of the semantics in unix(4).

Reviewed by:	dwmalone (eyeballed)

1 files changed, 4 insertions, 0 deletions

diff --git a/sys/sys/un.h b/sys/sys/un.h
index e7c3701..710f995 100644
--- a/sys/sys/un.h
+++ b/sys/sys/un.h
@@ -46,12 +46,16 @@ struct	sockaddr_un {
 	char	sun_path[104];		/* path name (gag) */
 };
 
+/* Socket options. */
+#define LOCAL_PEERCRED		0x001		/* retrieve peer credentails */
+
 #ifdef _KERNEL
 struct mbuf;
 struct socket;
 
 int	uipc_usrreq __P((struct socket *so, int req, struct mbuf *m,
 		struct mbuf *nam, struct mbuf *control));
+int	uipc_ctloutput __P((struct socket *so, struct sockopt *sopt));
 int	unp_connect2 __P((struct socket *so, struct socket *so2));
 void	unp_dispose __P((struct mbuf *m));
 int	unp_externalize __P((struct mbuf *rights));