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, 3 insertions, 0 deletions

diff --git a/lib/libpthread/support/thr_support.c b/lib/libpthread/support/thr_support.c
index 1b3c4ef..ad40fec 100644
--- a/lib/libpthread/support/thr_support.c
+++ b/lib/libpthread/support/thr_support.c
@@ -54,5 +54,8 @@ __strong_reference(memcpy, _thr_memcpy);
 __strong_reference(strcpy, _thr_strcpy);
 __strong_reference(strlen, _thr_strlen);
 __strong_reference(bzero, _thr_bzero);
+__strong_reference(bcopy, _thr_bcopy);
 
 __strong_reference(__sys_write, _thr__sys_write);
+__strong_reference(__sys_sigtimedwait, _thr__sys_sigtimedwait);
+