o Use a daemon thread to monitor signal events in kernel, if pending

  signals were changed in kernel, it will retrieve the pending set and
  try to find a thread to dispatch the signal. The dispatching process
  can be rolled back if the signal is no longer in kernel.

o Create two functions _thr_signal_init() and _thr_signal_deinit(),
  all signal action settings are retrieved from kernel when threading
  mode is turned on, after a fork(), child process will reset them to
  user settings by calling _thr_signal_deinit(). when threading mode
  is not turned on, all signal operations are direct past to kernel.

o When a thread generated a synchoronous signals and its context returned
  from completed list, UTS will retrieve the signal from its mailbox and try
  to deliver the signal to thread.

o Context signal mask is now only used when delivering signals, thread's
  current signal mask is always the one in pthread structure.

o Remove have_signals field in pthread structure, replace it with
  psf_valid in pthread_signal_frame. when psf_valid is true, in context
  switch time, thread will backout itself from some mutex/condition
  internal queues, then begin to process signals. when a thread is not
  at blocked state and running, check_pending indicates there are signals
  for the thread, after preempted and then resumed time, UTS will try to
  deliver signals to the thread.

o At signal delivering time, not only pending signals in thread will be
  scanned, process's pending signals will be scanned too.

o Change sigwait code a bit, remove field sigwait in pthread_wait_data,
  replace it with oldsigmask in pthread structure, when a thread calls
  sigwait(), its current signal mask is backuped to oldsigmask, and waitset
  is copied to its signal mask and when the thread gets a signal in the
  waitset range, its current signal mask is restored from oldsigmask,
  these are done in atomic fashion.

o Two additional POSIX APIs are implemented, sigwaitinfo() and sigtimedwait().

o Signal code locking is better than previous, there is fewer race conditions.

o Temporary disable most of code in _kse_single_thread as it is not safe
  after fork().

1 files changed, 15 insertions, 4 deletions

diff --git a/lib/libpthread/thread/thr_sigsuspend.c b/lib/libpthread/thread/thr_sigsuspend.c
index 2da790d..8d087f5 100644
--- a/lib/libpthread/thread/thr_sigsuspend.c
+++ b/lib/libpthread/thread/thr_sigsuspend.c
@@ -44,14 +44,19 @@ _sigsuspend(const sigset_t *set)
 {
 	struct pthread	*curthread = _get_curthread();
 	int             ret = -1;
+	sigset_t	osigmask;
+
+	if (!_kse_isthreaded())
+		return __sys_sigsuspend(set);
 
 	/* Check if a new signal set was provided by the caller: */
 	if (set != NULL) {
 		THR_LOCK_SWITCH(curthread);
 
+		/* Save current sigmask */
+		memcpy(&osigmask, &curthread->sigmask, sizeof(osigmask));
 		/* Change the caller's mask: */
-		memcpy(&curthread->tmbx.tm_context.uc_sigmask,
-		    set, sizeof(sigset_t));
+		memcpy(&curthread->sigmask, set, sizeof(sigset_t));
 
 		THR_SET_STATE(curthread, PS_SIGSUSPEND);
 
@@ -61,9 +66,15 @@ _sigsuspend(const sigset_t *set)
 		/* Always return an interrupted error: */
 		errno = EINTR;
 
+		THR_SCHED_LOCK(curthread, curthread);
 		/* Restore the signal mask: */
-		memcpy(&curthread->tmbx.tm_context.uc_sigmask,
-		    &curthread->sigmask, sizeof(sigset_t));
+		memcpy(&curthread->sigmask, &osigmask, sizeof(sigset_t));
+		THR_SCHED_UNLOCK(curthread, curthread);
+		/*
+		 * signal mask is reloaded, need to check if there is
+		 * pending proc signal I can handle.
+		 */
+		_thr_sig_check_pending(curthread);
 	} else {
 		/* Return an invalid argument error: */
 		errno = EINVAL;