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From: Andreas Schwab <schwab@sourceware.org>
To: glibc-cvs@sourceware.org
Subject: [glibc] socket: Use offsetof in SUN_LEN (bug 29578)
Date: Mon, 10 Oct 2022 07:32:39 +0000 (GMT)	[thread overview]
Message-ID: <20221010073239.AB8CE385829E@sourceware.org> (raw)

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c15318bfc5499d835c434a4d98b688aa2d928412

commit c15318bfc5499d835c434a4d98b688aa2d928412
Author: Andreas Schwab <schwab@suse.de>
Date:   Mon Sep 19 10:10:09 2022 +0200

    socket: Use offsetof in SUN_LEN (bug 29578)
    
    Use offsetof instead of its traditional expansion in the definition of the
    SUN_LEN macro, to avoid a warning from the undefined behaviour sanitizer.

Diff:
---
 socket/sys/un.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/socket/sys/un.h b/socket/sys/un.h
index 454eafebc9..2b11300e28 100644
--- a/socket/sys/un.h
+++ b/socket/sys/un.h
@@ -34,10 +34,11 @@ struct sockaddr_un
 
 
 #ifdef __USE_MISC
+# include <stddef.h>
 # include <string.h>		/* For prototype of `strlen'.  */
 
 /* Evaluate to actual length of the `sockaddr_un' structure.  */
-# define SUN_LEN(ptr) ((size_t) (((struct sockaddr_un *) 0)->sun_path)	      \
+# define SUN_LEN(ptr) (offsetof (struct sockaddr_un, sun_path)		      \
 		      + strlen ((ptr)->sun_path))
 #endif

                 reply	other threads:[~2022-10-10  7:32 UTC|newest]

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