From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Wed, 9 Mar 2022 21:22:46 +0000 (-0300)
Subject: posix: Fix macro expansion producing 'defined' has undefined behavior
X-Git-Tag: glibc-2.37~374
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ddcf5a9170a0db5055259118f3090debab248126;p=thirdparty%2Fglibc.git

posix: Fix macro expansion producing 'defined' has undefined behavior

The NEED_CHECK_SPEC is defined as:

  #define NEED_CHECK_SPEC \
    (!defined _XBS5_ILP32_OFF32 || !defined _XBS5_ILP32_OFFBIG \
     || !defined _XBS5_LP64_OFF64 || !defined _XBS5_LPBIG_OFFBIG \
     || !defined _POSIX_V6_ILP32_OFF32 || !defined _POSIX_V6_ILP32_OFFBIG \
     || !defined _POSIX_V6_LP64_OFF64 || !defined _POSIX_V6_LPBIG_OFFBIG \
     || !defined _POSIX_V7_ILP32_OFF32 || !defined _POSIX_V7_ILP32_OFFBIG \
     || !defined _POSIX_V7_LP64_OFF64 || !defined _POSIX_V7_LPBIG_OFFBIG)

Which is undefined behavior accordingly to C Standard (Preprocessing
directives, p4).

Checked on x86_64-linux-gnu.
---

diff --git a/sysdeps/posix/sysconf.c b/sysdeps/posix/sysconf.c
index f760bf4e2b6..c29b70ad805 100644
--- a/sysdeps/posix/sysconf.c
+++ b/sysdeps/posix/sysconf.c
@@ -37,13 +37,17 @@
 #define NEED_SPEC_ARRAY 0
 #include <posix-conf-vars.h>
 
-#define NEED_CHECK_SPEC \
-  (!defined _XBS5_ILP32_OFF32 || !defined _XBS5_ILP32_OFFBIG \
+#if !defined _XBS5_ILP32_OFF32 || !defined _XBS5_ILP32_OFFBIG \
    || !defined _XBS5_LP64_OFF64 || !defined _XBS5_LPBIG_OFFBIG \
    || !defined _POSIX_V6_ILP32_OFF32 || !defined _POSIX_V6_ILP32_OFFBIG \
    || !defined _POSIX_V6_LP64_OFF64 || !defined _POSIX_V6_LPBIG_OFFBIG \
    || !defined _POSIX_V7_ILP32_OFF32 || !defined _POSIX_V7_ILP32_OFFBIG \
-   || !defined _POSIX_V7_LP64_OFF64 || !defined _POSIX_V7_LPBIG_OFFBIG)
+   || !defined _POSIX_V7_LP64_OFF64 || !defined _POSIX_V7_LPBIG_OFFBIG
+# define NEED_CHECK_SPEC 1
+#else
+# define NEED_CHECK_SPEC 0
+#endif
+
 #if NEED_CHECK_SPEC
 static long int __sysconf_check_spec (const char *spec);
 #endif