In kern_sigsuspend(), better manipulate thread signal mask using

kern_sigprocmask() to properly notify other possible candidate threads
for signal delivery.

Since sigsuspend() shall only return to usermode after a signal was
delivered, do cursig/postsig loop immediately after waiting for
signal, repeating the wait if wakeup was spurious due to race with
other thread fetching signal from the process queue before us. Add
thread_suspend_check() call to allow the thread to be stopped or killed
while in loop.

Modify last argument of kern_sigprocmask() from boolean to flags,
allowing the function to be called with locked proc. Convertion of the
callers that supplied 1 to the old argument will be done in the next
commit, and due to SIGPROCMASK_OLD value equial to 1, code is formally
correct in between.

Reviewed by:	davidxu
Tested by:	pho
MFC after:	1 month

1 files changed, 1 insertions, 12 deletions

diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c
index 71b22aa..9f6b16d 100644
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -2579,21 +2579,10 @@ int
 ofreebsd32_sigsuspend(struct thread *td,
 			      struct ofreebsd32_sigsuspend_args *uap)
 {
-	struct proc *p = td->td_proc;
 	sigset_t mask;
 
-	PROC_LOCK(p);
-	td->td_oldsigmask = td->td_sigmask;
-	td->td_pflags |= TDP_OLDMASK;
 	OSIG2SIG(uap->mask, mask);
-	SIG_CANTMASK(mask);
-	SIGSETLO(td->td_sigmask, mask);
-	signotify(td);
-	while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "opause", 0) == 0)
-		/* void */;
-	PROC_UNLOCK(p);
-	/* always return EINTR rather than ERESTART... */
-	return (EINTR);
+	return (kern_sigsuspend(td, mask));
 }
 
 struct sigstack32 {