Add signal handler wrapper, the reason to add it becauses there are

some cases we want to improve:
  1) if a thread signal got a signal while in cancellation point,
     it is possible the TDP_WAKEUP may be eaten by signal handler
     if the handler called some interruptibly system calls.
  2) In signal handler, we want to disable cancellation.
  3) When thread holding some low level locks, it is better to
     disable signal, those code need not to worry reentrancy,
     sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
  1) libthr installs its signal handler if user code invokes sigaction
     to install its handler, the user handler is recorded in internal
     array.
  2) when a signal is delivered, libthr's signal handler is invoke,
     libthr checks if thread holds some low level lock or is in critical
     region, if it is true, the signal is buffered, and all signals are
     masked, once the thread leaves critical region, correct signal
     mask is restored and buffered signal is processed.
  3) before user signal handler is invoked, cancellation is temporarily
     disabled, after user signal handler is returned, cancellation state
     is restored, and pending cancellation is rescheduled.

1 files changed, 23 insertions, 10 deletions

diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h
index f261810..492d58d 100644
--- a/lib/libthr/thread/thr_private.h
+++ b/lib/libthr/thread/thr_private.h
@@ -376,12 +376,21 @@ struct pthread {
 	/* Thread temporary signal mask. */
 	sigset_t		sigmask;
 
-	/* Thread is in SIGCANCEL handler. */
-	int			in_sigcancel_handler;
-
-	/* New thread should unblock SIGCANCEL. */
+	/* Thread should unblock SIGCANCEL. */
 	int			unblock_sigcancel;
 
+	/* In sigsuspend state */
+	int			in_sigsuspend;
+
+	/* deferred signal info	*/
+	siginfo_t		deferred_siginfo;
+
+	/* signal mask to restore. */
+	sigset_t		deferred_sigmask;
+
+	/* the sigaction should be used for deferred signal. */
+	struct sigaction	deferred_sigact;
+
 	/* Force new thread to exit. */
 	int			force_exit;
 
@@ -629,6 +638,7 @@ void	_thr_ref_delete_unlocked(struct pthread *, struct pthread *) __hidden;
 int	_thr_find_thread(struct pthread *, struct pthread *, int) __hidden;
 void	_thr_rtld_init(void) __hidden;
 void	_thr_rtld_fini(void) __hidden;
+void	_thr_rtld_postfork_child(void) __hidden;
 int	_thr_stack_alloc(struct pthread_attr *) __hidden;
 void	_thr_stack_free(struct pthread_attr *) __hidden;
 void	_thr_free(struct pthread *, struct pthread *) __hidden;
@@ -637,10 +647,8 @@ void    _thread_cleanupspecific(void) __hidden;
 void	_thread_printf(int, const char *, ...) __hidden;
 void	_thr_spinlock_init(void) __hidden;
 void	_thr_cancel_enter(struct pthread *) __hidden;
-void	_thr_cancel_leave(struct pthread *) __hidden;
-void	_thr_cancel_leave2(struct pthread *, int) __hidden;
-void	_thr_cancel_enter_defer(struct pthread *, int) __hidden;
-void	_thr_cancel_leave_defer(struct pthread *, int) __hidden;
+void	_thr_cancel_enter2(struct pthread *, int) __hidden;
+void	_thr_cancel_leave(struct pthread *, int) __hidden;
 void	_thr_testcancel(struct pthread *) __hidden;
 void	_thr_signal_block(struct pthread *) __hidden;
 void	_thr_signal_unblock(struct pthread *) __hidden;
@@ -653,7 +661,6 @@ void	_thr_hash_remove(struct pthread *) __hidden;
 struct pthread *_thr_hash_find(struct pthread *) __hidden;
 void	_thr_link(struct pthread *, struct pthread *) __hidden;
 void	_thr_unlink(struct pthread *, struct pthread *) __hidden;
-void	_thr_suspend_check(struct pthread *) __hidden;
 void	_thr_assert_lock_level(void) __hidden __dead2;
 void	_thr_ast(struct pthread *) __hidden;
 void	_thr_once_init(void) __hidden;
@@ -662,6 +669,9 @@ void	_thr_report_creation(struct pthread *curthread,
 void	_thr_report_death(struct pthread *curthread) __hidden;
 int	_thr_getscheduler(lwpid_t, int *, struct sched_param *) __hidden;
 int	_thr_setscheduler(lwpid_t, int, const struct sched_param *) __hidden;
+void	_thr_signal_prefork(void) __hidden;
+void	_thr_signal_postfork(void) __hidden;
+void	_thr_signal_postfork_child(void) __hidden;
 int	_rtp_to_schedparam(const struct rtprio *rtp, int *policy,
 		struct sched_param *param) __hidden;
 int	_schedparam_to_rtp(int policy, const struct sched_param *param,
@@ -672,6 +682,8 @@ int	_sched_yield(void);
 
 void	_pthread_cleanup_push(void (*)(void *), void *);
 void	_pthread_cleanup_pop(int);
+void	_pthread_exit_mask(void *status, sigset_t *mask) __dead2 __hidden;
+
 
 /* #include <fcntl.h> */
 #ifdef  _SYS_FCNTL_H_
@@ -687,7 +699,7 @@ int     __sys_sigaction(int, const struct sigaction *, struct sigaction *);
 int     __sys_sigpending(sigset_t *);
 int     __sys_sigprocmask(int, const sigset_t *, sigset_t *);
 int     __sys_sigsuspend(const sigset_t *);
-int     __sys_sigreturn(ucontext_t *);
+int     __sys_sigreturn(const ucontext_t *);
 int     __sys_sigaltstack(const struct sigaltstack *, struct sigaltstack *);
 int	__sys_sigwait(const sigset_t *, int *);
 int	__sys_sigtimedwait(const sigset_t *, siginfo_t *,
@@ -740,6 +752,7 @@ _thr_check_init(void)
 struct dl_phdr_info;
 void __pthread_cxa_finalize(struct dl_phdr_info *phdr_info);
 void _thr_tsd_unload(struct dl_phdr_info *phdr_info) __hidden;
+void _thr_sigact_unload(struct dl_phdr_info *phdr_info) __hidden;
 
 __END_DECLS