As long as we have a knob to force system scope threads, why not have

a knob to force process scope threads.  If the environment variable
LIBPTHREAD_PROCESS_SCOPE is set, force all threads to be process
scope threads regardless of how the application creates them.  If
LIBPTHREAD_SYSTEM_SCOPE is set (forcing system scope threads), it
overrides LIBPTHREAD_PROCESS_SCOPE.

        $ # To force system scope threads
        $ LIBPTHREAD_SYSTEM_SCOPE=anything threaded_app
        $ # To force process scope threads
        $ LIBPTHREAD_PROCESS_SCOPE=anything threaded_app

4 files changed, 13 insertions, 8 deletions

diff --git a/lib/libkse/thread/thr_create.c b/lib/libkse/thread/thr_create.c
index 8c4592a..54bcd3b 100644
--- a/lib/libkse/thread/thr_create.c
+++ b/lib/libkse/thread/thr_create.c
@@ -126,8 +126,11 @@ _pthread_create(pthread_t * thread, const pthread_attr_t * attr,
 				 */
 			}
 		}
-		if (_thread_scope_system != 0)
+		if (_thread_scope_system > 0)
 			new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
+		else if ((_thread_scope_system < 0)
+		    && (thread != &_thr_sig_daemon))
+			new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
 		if (create_stack(&new_thread->attr) != 0) {
 			/* Insufficient memory to create a stack: */
 			ret = EAGAIN;
diff --git a/lib/libkse/thread/thr_exit.c b/lib/libkse/thread/thr_exit.c
index ec8e9ec..ecea47a 100644
--- a/lib/libkse/thread/thr_exit.c
+++ b/lib/libkse/thread/thr_exit.c
@@ -126,8 +126,8 @@ _pthread_exit(void *status)
 	KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
 	/* Use thread_list_lock */
 	_thread_active_threads--;
-	if ((_thread_scope_system == 0 && _thread_active_threads == 1) ||
-	    (_thread_scope_system != 0 && _thread_active_threads == 0)) {
+	if ((_thread_scope_system <= 0 && _thread_active_threads == 1) ||
+	    (_thread_scope_system > 0 && _thread_active_threads == 0)) {
 		KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
 		_kse_critical_leave(crit);
 		exit(0);
diff --git a/lib/libkse/thread/thr_init.c b/lib/libkse/thread/thr_init.c
index 6c371b0..baee1bb 100644
--- a/lib/libkse/thread/thr_init.c
+++ b/lib/libkse/thread/thr_init.c
@@ -258,7 +258,7 @@ _libpthread_init(struct pthread *curthread)
 	_kse_init();
 
 	/* Initialize the initial kse and kseg. */
-	_kse_initial = _kse_alloc(NULL, _thread_scope_system);
+	_kse_initial = _kse_alloc(NULL, _thread_scope_system > 0);
 	if (_kse_initial == NULL)
 		PANIC("Can't allocate initial kse.");
 	_kse_initial->k_kseg = _kseg_alloc(NULL);
@@ -469,6 +469,8 @@ init_private(void)
 #else
 	if (getenv("LIBPTHREAD_SYSTEM_SCOPE") != NULL)
 		_thread_scope_system = 1;
+	else if (getenv("LIBPTHREAD_PROCESS_SCOPE") != NULL)
+		_thread_scope_system = -1;
 #endif
 
 	/*
diff --git a/lib/libkse/thread/thr_kern.c b/lib/libkse/thread/thr_kern.c
index e29f985..926ca4b 100644
--- a/lib/libkse/thread/thr_kern.c
+++ b/lib/libkse/thread/thr_kern.c
@@ -75,8 +75,8 @@ __FBSDID("$FreeBSD$");
  * same number of KSEs and KSE groups as threads. Once these levels are
  * reached, any extra KSE and KSE groups will be free()'d.
  */
-#define	MAX_CACHED_KSES		((_thread_scope_system == 0) ? 50 : 100)
-#define	MAX_CACHED_KSEGS	((_thread_scope_system == 0) ? 50 : 100)
+#define	MAX_CACHED_KSES		((_thread_scope_system <= 0) ? 50 : 100)
+#define	MAX_CACHED_KSEGS	((_thread_scope_system <= 0) ? 50 : 100)
 
 #define	KSE_SET_MBOX(kse, thrd) \
 	(kse)->k_kcb->kcb_kmbx.km_curthread = &(thrd)->tcb->tcb_tmbx
@@ -407,7 +407,7 @@ _kse_setthreaded(int threaded)
 		 */
 		_kse_initial->k_flags |= KF_STARTED;
 
-		if (_thread_scope_system == 0) {
+		if (_thread_scope_system <= 0) {
 			_thr_initial->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
 			_kse_initial->k_kseg->kg_flags &= ~KGF_SINGLE_THREAD;
 			_kse_initial->k_kcb->kcb_kmbx.km_curthread = NULL;
@@ -439,7 +439,7 @@ _kse_setthreaded(int threaded)
 			_kse_initial->k_kcb->kcb_kmbx.km_lwp;
 		_thread_activated = 1;
 
-		if (_thread_scope_system == 0) {
+		if (_thread_scope_system <= 0) {
 			/* Set current thread to initial thread */
 			_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
 			KSE_SET_MBOX(_kse_initial, _thr_initial);