Use a generic way to back threads out of wait queues when handling

signals instead of having more intricate knowledge of thread state
within signal handling.

Simplify signal code because of above (by David Xu).

Use macros for libpthread usage of pthread_cleanup_push() and
pthread_cleanup_pop().  This removes some instances of malloc()
and free() from the semaphore and pthread_once() implementations.

When single threaded and forking(), make sure that the current
thread's signal mask is inherited by the forked thread.

Use private mutexes for libc and libpthread.  Signals are
deferred while threads hold private mutexes.  This fix also
breaks www/linuxpluginwrapper; a patch that fixes it is at
http://people.freebsd.org/~deischen/kse/linuxpluginwrapper.diff

Fix race condition in condition variables where handling a
signal (pthread_kill() or kill()) may not see a wakeup
(pthread_cond_signal() or pthread_cond_broadcast()).

In collaboration with:	davidxu

1 files changed, 19 insertions, 5 deletions

diff --git a/lib/libpthread/thread/thr_private.h b/lib/libpthread/thread/thr_private.h
index b8ccb43..9f9f505 100644
--- a/lib/libpthread/thread/thr_private.h
+++ b/lib/libpthread/thread/thr_private.h
@@ -416,8 +416,24 @@ struct pthread_cleanup {
 	struct pthread_cleanup	*next;
 	void			(*routine) ();
 	void			*routine_arg;
+	int			onstack;
 };
 
+#define	THR_CLEANUP_PUSH(td, func, arg) {		\
+	struct pthread_cleanup __cup;			\
+							\
+	__cup.routine = func;				\
+	__cup.routine_arg = arg;			\
+	__cup.onstack = 1;				\
+	__cup.next = (td)->cleanup;			\
+	(td)->cleanup = &__cup;
+
+#define	THR_CLEANUP_POP(td, exec)			\
+	(td)->cleanup = __cup.next;			\
+	if ((exec) != 0)				\
+		__cup.routine(__cup.routine_arg);	\
+}
+
 struct pthread_atfork {
 	TAILQ_ENTRY(pthread_atfork) qe;
 	void (*prepare)(void);
@@ -573,6 +589,7 @@ struct pthread_sigframe {
 	sigset_t		psf_sigset;
 	sigset_t		psf_sigmask;
 	int			psf_seqno;
+	thread_continuation_t	psf_continuation;
 };
 
 struct join_status {
@@ -645,8 +662,8 @@ struct pthread {
 	/*
 	 * Used for tracking delivery of signal handlers.
 	 */
-	struct pthread_sigframe	*curframe;
 	siginfo_t		*siginfo;
+	thread_continuation_t	sigbackout;
 
  	/*
 	 * Cancelability flags - the lower 2 bits are used by cancel
@@ -1070,7 +1087,6 @@ SCLASS int		_thr_debug_flags	SCLASS_PRESET(0);
  */
 __BEGIN_DECLS
 int	_cond_reinit(pthread_cond_t *);
-void	_cond_wait_backout(struct pthread *);
 struct kse *_kse_alloc(struct pthread *, int sys_scope);
 kse_critical_t _kse_critical_enter(void);
 void	_kse_critical_leave(kse_critical_t);
@@ -1085,7 +1101,6 @@ int	_kse_setthreaded(int);
 void	_kseg_free(struct kse_group *);
 int	_mutex_cv_lock(pthread_mutex_t *);
 int	_mutex_cv_unlock(pthread_mutex_t *);
-void	_mutex_lock_backout(struct pthread *);
 void	_mutex_notify_priochange(struct pthread *, struct pthread *, int);
 int	_mutex_reinit(struct pthread_mutex *);
 void	_mutex_unlock_private(struct pthread *);
@@ -1148,8 +1163,7 @@ void    _thr_set_timeout(const struct timespec *);
 void	_thr_seterrno(struct pthread *, int);
 void    _thr_sig_handler(int, siginfo_t *, ucontext_t *);
 void    _thr_sig_check_pending(struct pthread *);
-void	_thr_sig_rundown(struct pthread *, ucontext_t *,
-	    struct pthread_sigframe *);
+void	_thr_sig_rundown(struct pthread *, ucontext_t *);
 void	_thr_sig_send(struct pthread *pthread, int sig);
 void	_thr_sigframe_restore(struct pthread *thread, struct pthread_sigframe *psf);
 void	_thr_spinlock_init(void);