$OpenBSD: patch-rts_posix_Signals_c,v 1.2 2012/09/02 19:53:46 kili Exp $

There are several problems with the original code:

- It doesn't work with uthreads (instead of running the default
  handler, the custom handler is called again, which causes an
  endless cascade of signals once the process gets a SIGTSTP).

- It isn't posix compliant (sigprocmask(2) behaviour is unspecified for
  multithreaded processes, where you would have to use
  pthread_sigmask(3)).

- It's far too complicated compared to the simple kill(getpid(),
  SIGSTOP).

--- rts/posix/Signals.c.orig	Wed Feb  1 19:10:32 2012
+++ rts/posix/Signals.c	Sat Jun  9 21:36:25 2012
@@ -519,7 +519,7 @@ empty_handler (int sig STG_UNUSED)
 
    The trick we use is:
      - catch SIGTSTP
-     - in the handler,  kill(getpid(),SIGTSTP)
+     - in the handler,  kill(getpid(),SIGSTOP)
      - when this returns, restore the TTY settings
    This means we don't have to catch SIGCONT too.
 
@@ -541,17 +541,8 @@ sigtstp_handler (int sig)
         }
     }
 
-    // de-install the SIGTSTP handler
-    set_sigtstp_action(rtsFalse);
-
     // really stop the process now
-    {
-        sigset_t mask;
-        sigemptyset(&mask);
-        sigaddset(&mask, sig);
-        sigprocmask(SIG_UNBLOCK, &mask, NULL);
-        kill(getpid(), sig);
-    }
+    kill(getpid(), SIGSTOP);
 
     // on return, restore the TTY state
     for (fd = 0; fd <= 2; fd++) {
@@ -559,8 +550,6 @@ sigtstp_handler (int sig)
             tcsetattr(0,TCSANOW,&ts[fd]);
         }
     }
-
-    set_sigtstp_action(rtsTrue);
 }
 
 static void