From 5a731ab9ffbe33788aad636e2f8704e18e5bd254 Mon Sep 17 00:00:00 2001
From: ngie <ngie@FreeBSD.org>
Date: Sat, 3 Dec 2016 18:40:39 +0000
Subject: MFC r296386: r296386 (by pfg):

Work around aliasing issues detected in modern GCC.

Avoid casting gymnastics that lead to pointer aliasing by introducing an
inline function as done in NetBSD (but without #if0'd WIP code).

Obtained from:	NetBSD (CVS Rev. 1.24, 1.25)
---
 lib/libc/rpc/clnt_vc.c | 36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

(limited to 'lib/libc')

diff --git a/lib/libc/rpc/clnt_vc.c b/lib/libc/rpc/clnt_vc.c
index 37252e4..112b32e 100644
--- a/lib/libc/rpc/clnt_vc.c
+++ b/lib/libc/rpc/clnt_vc.c
@@ -503,6 +503,20 @@ clnt_vc_abort(CLIENT *cl)
 {
 }
 
+static __inline void
+htonlp(void *dst, const void *src, uint32_t incr)
+{
+	/* We are aligned, so we think */
+	*(uint32_t *)dst = htonl(*(const uint32_t *)src + incr);
+}
+
+static __inline void
+ntohlp(void *dst, const void *src)
+{
+	/* We are aligned, so we think */
+	*(uint32_t *)dst = htonl(*(const uint32_t *)src);
+}
+
 static bool_t
 clnt_vc_control(CLIENT *cl, u_int request, void *info)
 {
@@ -577,14 +591,12 @@ clnt_vc_control(CLIENT *cl, u_int request, void *info)
 		 * first element in the call structure
 		 * This will get the xid of the PREVIOUS call
 		 */
-		*(u_int32_t *)info =
-		    ntohl(*(u_int32_t *)(void *)&ct->ct_u.ct_mcalli);
+		ntohlp(info, &ct->ct_u.ct_mcalli);
 		break;
 	case CLSET_XID:
 		/* This will set the xid of the NEXT call */
-		*(u_int32_t *)(void *)&ct->ct_u.ct_mcalli =
-		    htonl(*((u_int32_t *)info) + 1);
 		/* increment by 1 as clnt_vc_call() decrements once */
+		htonlp(&ct->ct_u.ct_mcalli, info, 1);
 		break;
 	case CLGET_VERS:
 		/*
@@ -593,15 +605,11 @@ clnt_vc_control(CLIENT *cl, u_int request, void *info)
 		 * begining of the RPC header. MUST be changed if the
 		 * call_struct is changed
 		 */
-		*(u_int32_t *)info =
-		    ntohl(*(u_int32_t *)(void *)(ct->ct_u.ct_mcallc +
-		    4 * BYTES_PER_XDR_UNIT));
+		ntohlp(info, ct->ct_u.ct_mcallc + 4 * BYTES_PER_XDR_UNIT);
 		break;
 
 	case CLSET_VERS:
-		*(u_int32_t *)(void *)(ct->ct_u.ct_mcallc +
-		    4 * BYTES_PER_XDR_UNIT) =
-		    htonl(*(u_int32_t *)info);
+		htonlp(ct->ct_u.ct_mcallc + 4 * BYTES_PER_XDR_UNIT, info, 0);
 		break;
 
 	case CLGET_PROG:
@@ -611,15 +619,11 @@ clnt_vc_control(CLIENT *cl, u_int request, void *info)
 		 * begining of the RPC header. MUST be changed if the
 		 * call_struct is changed
 		 */
-		*(u_int32_t *)info =
-		    ntohl(*(u_int32_t *)(void *)(ct->ct_u.ct_mcallc +
-		    3 * BYTES_PER_XDR_UNIT));
+		ntohlp(info, ct->ct_u.ct_mcallc + 3 * BYTES_PER_XDR_UNIT);
 		break;
 
 	case CLSET_PROG:
-		*(u_int32_t *)(void *)(ct->ct_u.ct_mcallc +
-		    3 * BYTES_PER_XDR_UNIT) =
-		    htonl(*(u_int32_t *)info);
+		htonlp(ct->ct_u.ct_mcallc + 3 * BYTES_PER_XDR_UNIT, info, 0);
 		break;
 
 	default:
-- 
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