/* $NetBSD: getpeereid.c,v 1.4 2021/08/08 20:54:48 nia Exp $ */

/*-
 * Copyright (c) 2007 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Arne H. Juul.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: getpeereid.c,v 1.4 2021/08/08 20:54:48 nia Exp $");
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/un.h>
#include <sys/socket.h>
#include <unistd.h>
#include <errno.h>


int
getpeereid(int s, uid_t *euid, gid_t *egid)
{
	struct unpcbid cred;
	struct sockaddr_storage ss;
	socklen_t len;

	len = sizeof(ss);
	if (getsockname(s, (void *)&ss, &len) == -1)
		return -1;
	if (ss.ss_family != AF_LOCAL) {
		errno = EOPNOTSUPP;
		return -1;
	}

	len = sizeof(cred);
	if (getsockopt(s, SOL_LOCAL, LOCAL_PEEREID, &cred, &len) == -1)
		return -1;

	if (euid != NULL)
		*euid = cred.unp_euid;
	if (egid != NULL)
		*egid = cred.unp_egid;
	return 0;
}