[krbdev.mit.edu #3358] krb5 doesn't build when pthread_mutexattr_setrobust_np is defined but not declared

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Date: Thu, 19 Jan 2006 19:16:20 -0500
Message-Id: <200601200016.k0K0GKtj030516 at rapier.boston.redhat.com>
To: krb5-bugs at mit.edu
Subject: build failure when pthread_mutexattr_setrobust_np is defined but not
	declared
From: nalin at redhat.com
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>Submitter-Id:	net
>Originator:	Nalin Dahyabhai
>Organization:
>Confidential:	no
>Synopsis:	krb5 doesn't build when pthread_mutexattr_setrobust_np is defined but not declared
>Severity:	non-critical
>Priority:	medium
>Category:	krb5-build
>Class:		sw-bug
>Release:	1.4.3
>Environment:
	
System: Linux rapier.boston.redhat.com 2.6.15-1.1826.2.10_FC5 #1 Wed Jan 11 18:12:42 EST 2006 i686 i686 i386 GNU/Linux
Architecture: i686

>Description:
	Attempts to build the 1.4.3 release with a recent glibc snapshot (mine
	identifies itself as 2.3.90, for what that's worth) fail because while
	libpthread provides the pthread_mutexattr_setrobust_np symbol, the
	header only declares it if _GNU_SOURCE is defined.  This is not the
	default for Kerberos 5, but the configure script detects the symbol and
	defines HAVE_PTHREAD_MUTEXATTR_SETROBUST_MP, causing a compile failure
	when src/util/support/threads.c attempts to use take the address of the
	function.
>How-To-Repeat:
	Attempt to build against the same version of glibc (or Fedora Core,
	development version), or after temporarily removing the declaration of
	the function from a system which provides it from whichever header
	declares it.
>Fix:
	Checking if the function is both declared and defined seems to be the
	dependable way to handle it.  A patch:

--- krb5-1.4.3/src/aclocal.m4	2006-01-19 18:56:17.000000000 -0500
+++ krb5-1.4.3/src/aclocal.m4	2006-01-19 18:56:11.000000000 -0500
@@ -171,7 +171,14 @@
 dnl reference support we can figure out whether or not the pthread library
 dnl has been linked in.
 dnl If we don't add any libraries for thread support, don't bother.
-AC_CHECK_FUNCS(pthread_once pthread_mutexattr_setrobust_np pthread_rwlock_init)
+for fn in pthread_once pthread_mutexattr_setrobust_np pthread_rwlock_init ; do
+	AC_CHECK_DECLS($fn,,,[
+	#ifdef HAVE_PTHREAD
+	#include <pthread.h>
+	#endif
+	])
+	AC_CHECK_FUNCS($fn)
+done
 old_CC="$CC"
 test "$PTHREAD_CC" != "" && test "$ac_cv_c_compiler_gnu" = no && CC=$PTHREAD_CC
 old_CFLAGS="$CFLAGS"
--- krb5-1.4.3/src/util/support/threads.c	2005-08-12 16:57:07.000000000 -0400
+++ krb5-1.4.3/src/util/support/threads.c	2006-01-19 19:00:59.000000000 -0500
@@ -141,7 +141,7 @@
 	|| &pthread_equal == 0
 	/* This catches Solaris 9.  May be redundant with the above
 	   tests now.  */
-# ifdef HAVE_PTHREAD_MUTEXATTR_SETROBUST_NP_IN_THREAD_LIB
+# if defined(HAVE_PTHREAD_MUTEXATTR_SETROBUST_NP_IN_THREAD_LIB) && HAVE_DECL_PTHREAD_MUTEXATTR_SETROBUST_NP
 	|| &pthread_mutexattr_setrobust_np == 0
 # endif
 	/* Any program that's really multithreaded will have to be