Hi,

Does anyone know if Ultrix signal emulation -- callouts from
the kernel to an emul_ultrix process's signal handler, and
then returning -- ever worked properly?

I'm finding the following (emacs-19's wakeup.c) works
fine as a native binary, but if compiled for Ultrix,
ktrace shows it gets a SIGLARM but then gets a SIGILL
before returning from (or executing?) the handler.

  1834 wakeup   CALL  setitimer(0,0x7ffffa10,0)
  1834 wakeup   RET   setitimer -4176/0xffffefb0
  1834 wakeup   CALL  sigsuspend(0)
  1834 wakeup   RET   sigsuspend -1 errno 4 Interrupted system call
  1834 wakeup   PSIG  SIGALRM caught handler=0x401930 mask=0xfffefeff code=0x0
  1834 wakeup   PSIG  SIGILL SIG_DFL
  1834 wakeup   NAMI  "wakeup.core"

The recorded PC in the corefile is above the user stack, which
suggests that delivery of the signal (or returning from it)
is broken.

I thought this used to work, but maybe not...


/* Program to produce output at regular intervals.  */

#include <stdio.h>
#include <sys/types.h>

#include <sys/time.h>
#include <time.h>

struct tm *localtime ();

void
main (argc, argv)
     int argc;
     char **argv;
{
  int period = 60;
  time_t when;
  struct tm *tp;

  if (argc > 1)
    period = atoi (argv[1]);

  while (1)
    {
      /* Make sure wakeup stops when Emacs goes away.  */
      if (getppid () == 1)
	exit (0);
      printf ("Wake up!\n");
      fflush (stdout);
      /* If using a period of 60, produce the output when the minute
	 changes. */
      if (period == 60)
	{
	  time (&when);
	  tp = localtime (&when);
	  sleep (60 - tp->tm_sec);
	}
      else
	sleep (period);
    }
}