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From: Siddhesh Poyarekar <siddhesh@sourceware.org>
To: libc-alpha@sourceware.org
Cc: fweimer@redhat.com
Subject: [PATCH] cdefs: Limit definition of fortification macros
Date: Mon, 30 Jan 2023 08:32:17 -0500	[thread overview]
Message-ID: <20230130133217.497398-1-siddhesh@sourceware.org> (raw)
In-Reply-To: <87v8koxkel.fsf@oldenburg.str.redhat.com>

Define the __glibc_fortify and other macros only when __FORTIFY_LEVEL >
0.  This has the effect of not defining these macros on older C90
compilers that do not have support for variable length argument lists.

Also trim off the trailing backslashes from the definition of
__glibc_fortify and __glibc_fortify_n macros.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
---

Only tested for sanity.  Florian, can you please verify that this
resolves the original problem?

 misc/sys/cdefs.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 66d6702123..c37a3ff637 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -152,6 +152,7 @@
 # define __glibc_objsize(__o) __bos (__o)
 #endif
 
+#if __USE_FORTIFY_LEVEL > 0
 /* Compile time conditions to choose between the regular, _chk and _chk_warn
    variants.  These conditions should get evaluated to constant and optimized
    away.  */
@@ -187,7 +188,7 @@
    ? __ ## f ## _alias (__VA_ARGS__)					      \
    : (__glibc_unsafe_len (__l, __s, __osz)				      \
       ? __ ## f ## _chk_warn (__VA_ARGS__, __osz)			      \
-      : __ ## f ## _chk (__VA_ARGS__, __osz)))			      \
+      : __ ## f ## _chk (__VA_ARGS__, __osz)))
 
 /* Fortify function f, where object size argument passed to f is the number of
    elements and not total size.  */
@@ -197,7 +198,8 @@
    ? __ ## f ## _alias (__VA_ARGS__)					      \
    : (__glibc_unsafe_len (__l, __s, __osz)				      \
       ? __ ## f ## _chk_warn (__VA_ARGS__, (__osz) / (__s))		      \
-      : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s))))		      \
+      : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s))))
+#endif
 
 #if __GNUC_PREREQ (4,3)
 # define __warnattr(msg) __attribute__((__warning__ (msg)))
-- 
2.38.1


  reply	other threads:[~2023-01-30 13:32 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-30  7:58 C90 header compatibility Florian Weimer
2023-01-30 12:26 ` Siddhesh Poyarekar
2023-01-30 12:43   ` Florian Weimer
2023-01-30 13:32     ` Siddhesh Poyarekar [this message]
2023-02-01 17:48       ` [PATCH] cdefs: Limit definition of fortification macros Florian Weimer

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