Change threxit() to take a pointer to a pid_t to zero out from the

kernel so that librthread can detect when a thread is completely
done with its stack without need a kqueue.  The dying thread moves
itself to a GC list, other threads scan the GC list on pthread_create()
and pthread_join() and free the stack and handle once the thread's
thread id is zeroed.

"get it in" deraadt@, tedu@, cheers by others

4 files changed, 13 insertions, 7 deletions

diff --git a/sys/kern/init_sysent.c b/sys/kern/init_sysent.c
index 57e5610efa9..c8f844ab9b6 100644
--- a/sys/kern/init_sysent.c
+++ b/sys/kern/init_sysent.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: init_sysent.c,v 1.107 2009/06/15 17:31:49 deraadt Exp $	*/
+/*	$OpenBSD: init_sysent.c,v 1.108 2009/11/27 19:42:24 guenther Exp $	*/
 
 /*
  * System call switch table.
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index b8336c38499..638610c7d25 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_exit.c,v 1.86 2009/10/05 17:43:07 deraadt Exp $	*/
+/*	$OpenBSD: kern_exit.c,v 1.87 2009/11/27 19:42:24 guenther Exp $	*/
 /*	$NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $	*/
 
 /*
@@ -95,10 +95,16 @@ int
 sys_threxit(struct proc *p, void *v, register_t *retval)
 {
 	struct sys_threxit_args /* {
-		syscallarg(int) rval;
+		syscallarg(pid_t *) notdead;
 	} */ *uap = v;
 
-	exit1(p, W_EXITCODE(SCARG(uap, rval), 0), EXIT_THREAD);
+	if (SCARG(uap, notdead) != NULL) {
+		pid_t zero = 0;
+		if (copyout(&zero, SCARG(uap, notdead), sizeof(zero))) {
+			psignal(p, SIGSEGV);
+		}
+	}
+	exit1(p, 0, EXIT_THREAD);
 
 	return (0);
 }
diff --git a/sys/kern/syscalls.c b/sys/kern/syscalls.c
index 872f29c18d5..3808639d1cf 100644
--- a/sys/kern/syscalls.c
+++ b/sys/kern/syscalls.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: syscalls.c,v 1.108 2009/06/15 17:31:49 deraadt Exp $	*/
+/*	$OpenBSD: syscalls.c,v 1.109 2009/11/27 19:42:24 guenther Exp $	*/
 
 /*
  * System call names.
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 686f7074b43..a4d507d5f0e 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -1,4 +1,4 @@
-;	$OpenBSD: syscalls.master,v 1.93 2009/06/03 15:42:03 jj Exp $
+;	$OpenBSD: syscalls.master,v 1.94 2009/11/27 19:42:24 guenther Exp $
 ;	$NetBSD: syscalls.master,v 1.32 1996/04/23 10:24:21 mycroft Exp $
 
 ;	@(#)syscalls.master	8.2 (Berkeley) 1/13/94
@@ -599,7 +599,7 @@
 299	STD		{ pid_t sys_getthrid(void); }
 300	STD		{ int sys_thrsleep(void *ident, int timeout, void *lock); }
 301	STD		{ int sys_thrwakeup(void *ident, int n); }
-302	STD		{ void sys_threxit(int rval); }
+302	STD		{ void sys_threxit(pid_t *notdead); }
 303	STD		{ int sys_thrsigdivert(sigset_t sigmask); }
 #else
 299	UNIMPL