From 8d48e738b5f20de3526e7640ae5823916127b193 Mon Sep 17 00:00:00 2001
From: "Pedro F. Giffuni" <pfg@FreeBSD.org>
Date: Fri, 23 Feb 2018 00:28:00 +0000
Subject: [PATCH] getpeereid(3): Fix behavior on failure to match
 documentation.

According to the getpeereid(3) documentation, on failure the value -1 is
returned and the global variable errno is set to indicate the error. We
were returning the error instead.

Obtained from:	Apple's Libc-1244.30.3
MFC after:	5 days
---
 lib/libc/gen/getpeereid.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/libc/gen/getpeereid.c b/lib/libc/gen/getpeereid.c
index 09f513502ecf..530ae0e6100e 100644
--- a/lib/libc/gen/getpeereid.c
+++ b/lib/libc/gen/getpeereid.c
@@ -50,8 +50,10 @@ getpeereid(int s, uid_t *euid, gid_t *egid)
 	error = _getsockopt(s, 0, LOCAL_PEERCRED, &xuc, &xuclen);
 	if (error != 0)
 		return (error);
-	if (xuc.cr_version != XUCRED_VERSION)
-		return (EINVAL);
+	if (xuc.cr_version != XUCRED_VERSION) {
+		errno = EINVAL;
+		return (-1);
+	}
 	*euid = xuc.cr_uid;
 	*egid = xuc.cr_gid;
 	return (0);