Check pending signals, if there is signal will be unblocked by

sigsuspend, thread shouldn't wait, in old code, it may be
ignored.
When a signal handler is invoked in sigsuspend, thread gets
two different signal masks, one is in thread structure,
sigprocmask() can retrieve it, another is in ucontext
which is a third parameter of signal handler, the former is
the result of sigsuspend mask ORed with sigaction's sa_mask
and current signal, the later is the mask in thread structure
before sigsuspend is called. After signal handler is called,
the mask in ucontext should be copied into thread structure,
and becomes CURRENT signal mask, then sigsuspend returns to
user code.

Reviewed by: deischen
Tested by: Sean McNeil <sean@mcneil.com>

4 files changed, 25 insertions, 22 deletions

diff --git a/lib/libkse/thread/thr_create.c b/lib/libkse/thread/thr_create.c
index 38c2fc4..0f7cbab 100644
--- a/lib/libkse/thread/thr_create.c
+++ b/lib/libkse/thread/thr_create.c
@@ -256,6 +256,7 @@ _pthread_create(pthread_t * thread, const pthread_attr_t * attr,
 			new_thread->sigstk.ss_sp = 0;
 			new_thread->sigstk.ss_size = 0;
 			new_thread->sigstk.ss_flags = SS_DISABLE;
+			new_thread->oldsigmask = NULL;
 
 			if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) {
 				new_thread->state = PS_SUSPENDED;
diff --git a/lib/libkse/thread/thr_private.h b/lib/libkse/thread/thr_private.h
index 191f9c1..98c967b 100644
--- a/lib/libkse/thread/thr_private.h
+++ b/lib/libkse/thread/thr_private.h
@@ -657,6 +657,7 @@ struct pthread {
 	 */
 	sigset_t		sigmask;
 	sigset_t		sigpend;
+	sigset_t		*oldsigmask;
 	volatile int		check_pending;
 	int			refcount;
 
diff --git a/lib/libkse/thread/thr_sig.c b/lib/libkse/thread/thr_sig.c
index 2a8d667..010a999 100644
--- a/lib/libkse/thread/thr_sig.c
+++ b/lib/libkse/thread/thr_sig.c
@@ -463,7 +463,11 @@ thr_sig_invoke_handler(struct pthread *curthread, int sig, siginfo_t *info,
 	ucp->uc_stack = curthread->sigstk;
 	ucp->uc_stack.ss_flags = (curthread->sigstk.ss_flags & SS_DISABLE)
 		? SS_DISABLE : ((onstack) ? SS_ONSTACK : 0);
-	ucp->uc_sigmask = sigmask;
+	if (curthread->oldsigmask) {
+		ucp->uc_sigmask = *(curthread->oldsigmask);
+		curthread->oldsigmask = NULL;
+	} else
+		ucp->uc_sigmask = sigmask;
 	shi.sigfunc = sigfunc;
 	shi.sig = sig;
 	shi.sa_flags = sa_flags;
diff --git a/lib/libkse/thread/thr_sigsuspend.c b/lib/libkse/thread/thr_sigsuspend.c
index cad5745..b7802e3 100644
--- a/lib/libkse/thread/thr_sigsuspend.c
+++ b/lib/libkse/thread/thr_sigsuspend.c
@@ -44,7 +44,7 @@ int
 _sigsuspend(const sigset_t *set)
 {
 	struct pthread	*curthread = _get_curthread();
-	sigset_t	oldmask, newmask;
+	sigset_t	oldmask, newmask, tempset;
 	int             ret = -1;
 
 	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
@@ -54,32 +54,29 @@ _sigsuspend(const sigset_t *set)
 	if (set != NULL) {
 		newmask = *set;
 		SIG_CANTMASK(newmask);
-
 		THR_LOCK_SWITCH(curthread);
 
-		/* Save current sigmask */
-		memcpy(&oldmask, &curthread->sigmask, sizeof(sigset_t));
+		/* Save current sigmask: */
+		oldmask = curthread->sigmask;
+		curthread->oldsigmask = &oldmask;
 
 		/* Change the caller's mask: */
-		memcpy(&curthread->sigmask, &newmask, sizeof(sigset_t));
-
-		THR_SET_STATE(curthread, PS_SIGSUSPEND);
-
-		/* Wait for a signal: */
-		_thr_sched_switch_unlocked(curthread);
-
+		curthread->sigmask = newmask;
+		tempset = curthread->sigpend;
+		SIGSETNAND(tempset, newmask);
+		if (SIGISEMPTY(tempset)) {
+			THR_SET_STATE(curthread, PS_SIGSUSPEND);
+			/* Wait for a signal: */
+			_thr_sched_switch_unlocked(curthread);
+		} else {
+			THR_UNLOCK_SWITCH(curthread);
+			/* check pending signal I can handle: */
+			_thr_sig_check_pending(curthread);
+		}
+		THR_ASSERT(curthread->oldsigmask == NULL,
+		           "oldsigmask is not cleared");
 		/* Always return an interrupted error: */
 		errno = EINTR;
-
-		THR_SCHED_LOCK(curthread, curthread);
-		/* Restore the signal mask: */
-		memcpy(&curthread->sigmask, &oldmask, 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;