* configure.in: Remove bogus check to test whether defining

_POSIX_THREAD_PRIO_INHERIT makes pthread_mutexattr_setrobust_np
available; the former is a POSIX feature test macro and is defined (or
not) by unistd.h, not the application.

* locks/unix/proc_mutex.c (proc_mutex_proc_pthread_create): Make
explicit the assumption that robust mutexes are only used if priority
inheritance is supported; this prevents use of robust mutexes with
glibc 2.3, which aren't supported for cross-process use.

PR: 38442


git-svn-id: http://svn.apache.org/repos/asf/apr/apr/trunk@380120 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 10 insertions, 19 deletions

diff --git a/configure.in b/configure.in
index beeda49df..c8059db74 100644
--- a/configure.in
+++ b/configure.in
@@ -1604,23 +1604,6 @@ if test "$threads" = "1"; then
 
     if test "$ac_cv_func_pthread_mutexattr_setpshared" = "yes"; then
         AC_CHECK_FUNCS(pthread_mutexattr_setrobust_np)
-        if test "$ac_cv_func_pthread_mutexattr_setrobust_np" = "no"; then
-            AC_CACHE_CHECK([for pthread_mutexattr_setrobust_np with _POSIX_THREAD_PRIO_INHERIT],
-            [apr_cv_setrobust_with_prio_inherit], [
-            AC_TRY_COMPILE([#define _POSIX_THREAD_PRIO_INHERIT
-#include <sys/types.h>
-#include <pthread.h>],[
-            int main()
-            {
-                pthread_mutexattr_t attr;
-                pthread_mutexattr_setrobust_np(&attr, PTHREAD_MUTEX_ROBUST_NP);
-                return 0;
-            }], [apr_cv_setrobust_with_prio_inherit=yes], [apr_cv_setrobust_with_prio_inherit=no])])
-            if test "$apr_cv_setrobust_with_prio_inherit" = "yes"; then
-                ac_cv_func_pthread_mutexattr_setrobust_np=yes
-                APR_ADDTO(CPPFLAGS, -D_POSIX_THREAD_PRIO_INHERIT)
-            fi
-        fi
     fi
 fi
 
diff --git a/locks/unix/proc_mutex.c b/locks/unix/proc_mutex.c
index 98fb2eb1e..514bebabe 100644
--- a/locks/unix/proc_mutex.c
+++ b/locks/unix/proc_mutex.c
@@ -325,7 +325,15 @@ static apr_status_t proc_mutex_proc_pthread_create(apr_proc_mutex_t *new_mutex,
         return rv;
     }
 
-#ifdef HAVE_PTHREAD_MUTEXATTR_SETROBUST_NP
+    /* It is strictly not necessary to only enable robust mutexes iff
+     * priority inheritance is supported, but historically this always
+     * has been the case.  glibc 2.3 supports robust mutexes, but not
+     * cross-process robust mutexes, so enabling the robust mutex
+     * support like this ensures it is only used on Solaris, for now.
+     * A (more complicated) configure check would be necessary
+     * otherwise. */
+#if defined(HAVE_PTHREAD_MUTEXATTR_SETROBUST_NP) \
+    && defined(_POSIX_THREAD_PRIO_INHERIT) && _POSIX_THREAD_PRIO_INHERIT > 0
     if ((rv = pthread_mutexattr_setrobust_np(&mattr, 
                                                PTHREAD_MUTEX_ROBUST_NP))) {
 #ifdef PTHREAD_SETS_ERRNO
@@ -343,7 +351,7 @@ static apr_status_t proc_mutex_proc_pthread_create(apr_proc_mutex_t *new_mutex,
         pthread_mutexattr_destroy(&mattr);
         return rv;
     }
-#endif
+#endif /* HAVE_PTHREAD_MUTEXATTR_SETROBUST_NP && _POSIX_THREAD_PRIO_INHERIT > 0 */
 
     if ((rv = pthread_mutex_init(new_mutex->pthread_interproc, &mattr))) {
 #ifdef PTHREAD_SETS_ERRNO