Thu Jan 4 11:35:18 1996 Roland McGrath <roland@churchy.gnu.ai.mit.edu>

	* sysdeps/mach/hurd/setitimer.c: Code rearranged a bit to use new
	preemption interface.

	* sysdeps/mach/hurd/i386/trampoline.c (_hurd_setup_sighandler):
	Use _hurdsig_catch_memory_fault.

	* hurd/Makefile (headers): Add hurd/sigpreempt.h.
	(sig): Add catch-signal.

	* hurd/hurdfault.c (_hurdsig_fault_catch_exception_raise):
	Rewritten using a preempter in new interface.
	* hurd/hurdfault.h (_hurdsig_catch_fault): Likewise.
	(_hurdsig_catch_memory_fault): New macro.

2 files changed, 47 insertions, 44 deletions

diff --git a/sysdeps/mach/hurd/i386/trampoline.c b/sysdeps/mach/hurd/i386/trampoline.c
index 9e947a46e7..f64539a384 100644
--- a/sysdeps/mach/hurd/i386/trampoline.c
+++ b/sysdeps/mach/hurd/i386/trampoline.c
@@ -1,5 +1,5 @@
 /* Set thread_state for sighandler, and sigcontext to recover.  i386 version.
-Copyright (C) 1994, 1995 Free Software Foundation, Inc.
+Copyright (C) 1994, 1995, 1996 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
 
 The GNU C Library is free software; you can redistribute it and/or
@@ -24,7 +24,7 @@ Cambridge, MA 02139, USA.  */
 #include <errno.h>
 #include "hurdfault.h"
 
-     
+
 struct mach_msg_trap_args
   {
     void *retaddr;		/* Address mach_msg_trap will return to.  */
@@ -50,7 +50,7 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
   extern const void _hurd_intr_rpc_msg_sp_restored;
   void *volatile sigsp;
   struct sigcontext *scp;
-  struct 
+  struct
     {
       int signo;
       long int sigcode;
@@ -67,10 +67,7 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
       /* We have a previous sigcontext that sigreturn was about
 	 to restore when another signal arrived.  We will just base
 	 our setup on that.  */
-      if (_hurdsig_catch_fault (SIGSEGV))
-	assert (_hurdsig_fault_sigcode >= (long int) ss->context &&
-		_hurdsig_fault_sigcode < (long int) (ss->context + 1));
-      else
+      if (! _hurdsig_catch_memory_fault (ss->context))
 	{
 	  memcpy (&state->basic, &ss->context->sc_i386_thread_state,
 		  sizeof (state->basic));
@@ -97,7 +94,7 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
 	 per-thread variables, cthreads.  */
     }
   /* This code has intimate knowledge of the special mach_msg system call
-     done in intr-msg.c; that code does: 
+     done in intr-msg.c; that code does:
 					movl %esp, %ecx
 					leal ARGS, %esp
 	_hurd_intr_rpc_msg_cx_sp:	movl $-25, %eax
@@ -107,7 +104,7 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
      We must check for the window during which %esp points at the
      mach_msg arguments.  The space below until %ecx is used by
      the _hurd_intr_rpc_mach_msg frame, and must not be clobbered.  */
-  else if (state->basic.eip >= (int) &_hurd_intr_rpc_msg_cx_sp && 
+  else if (state->basic.eip >= (int) &_hurd_intr_rpc_msg_cx_sp &&
 	   state->basic.eip < (int) &_hurd_intr_rpc_msg_sp_restored)
     /* The SP now points at the mach_msg args, but there is more stack
        space used below it.  The real SP is saved in %ecx; we must push the
@@ -121,10 +118,8 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
   sigsp -= sizeof (*stackframe);
   stackframe = sigsp;
 
-  if (_hurdsig_catch_fault (SIGSEGV))
+  if (_hurdsig_catch_memory_fault (stackframe))
     {
-      assert (_hurdsig_fault_sigcode >= (long int) stackframe &&
-	      _hurdsig_fault_sigcode <= (long int) (stackframe + 1));
       /* We got a fault trying to write the stack frame.
 	 We cannot set up the signal handler.
 	 Returning NULL tells our caller, who will nuke us with a SIGILL.  */
@@ -187,17 +182,15 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
 	 still waiting for a reply.  We will have it run the special
 	 trampoline code which retries the message receive before running
 	 the signal handler.
-	 
+
 	 To do this we change the OPTION argument on its stack to enable only
 	 message reception, since the request message has already been
 	 sent.  */
 
       struct mach_msg_trap_args *args = (void *) state->basic.esp;
 
-      if (_hurdsig_catch_fault (SIGSEGV))
+      if (_hurdsig_catch_memory_fault (args))
 	{
-	  assert (_hurdsig_fault_sigcode >= (long int) args &&
-		  _hurdsig_fault_sigcode < (long int) (args + 1));
 	  /* Faulted accessing ARGS.  Bomb.  */
 	  return NULL;
 	}
diff --git a/sysdeps/mach/hurd/setitimer.c b/sysdeps/mach/hurd/setitimer.c
index 4f494a4c6e..cba1d0e65a 100644
--- a/sysdeps/mach/hurd/setitimer.c
+++ b/sysdeps/mach/hurd/setitimer.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1994, 1995 Free Software Foundation, Inc.
+/* Copyright (C) 1994, 1995, 1996 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
 
 The GNU C Library is free software; you can redistribute it and/or
@@ -22,6 +22,7 @@ Cambridge, MA 02139, USA.  */
 #include <sys/time.h>
 #include <hurd.h>
 #include <hurd/signal.h>
+#include <hurd/sigpreempt.h>
 #include <hurd/msg_request.h>
 #include <mach/message.h>
 
@@ -109,9 +110,29 @@ timer_thread (void)
     }
 }
 
-/* Forward declaration.  */
-static sighandler_t preempt_sigalrm (thread_t thread, int signo,
-				     long int sigcode, int sigerror);
+
+static sighandler_t
+restart_itimer (struct hurd_signal_preempter *preempter,
+		struct hurd_sigstate *ss,
+		int *signo, long int *sigcode,
+		int *sigerror)
+{
+  static int setitimer_locked (const struct itimerval *new,
+			       struct itimerval *old, void *crit);
+
+  /* This function gets called in the signal thread
+     each time a SIGALRM is arriving (even if blocked).  */
+  struct itimerval it;
+
+  /* Either reload or disable the itimer.  */
+  __spin_lock (&_hurd_itimer_lock);
+  it.it_value = it.it_interval = _hurd_itimerval.it_interval;
+  setitimer_locked (&it, NULL, NULL);
+
+  /* Continue with normal delivery (or hold, etc.) of SIGALRM.  */
+  return SIG_ERR;
+}
+
 
 /* Called before any normal SIGALRM signal is delivered.
    Reload the itimer, or disable the itimer.  */
@@ -138,12 +159,20 @@ setitimer_locked (const struct itimerval *new, struct itimerval *old,
     {
       /* Make sure the itimer thread is set up.  */
 
-      if (_hurd_signal_preempt[SIGALRM] == NULL)
+      /* Set up a signal preempter global for all threads to
+	 run `restart_itimer' each time a SIGALRM would arrive.  */
+      static struct hurd_signal_preempter preempter =
+	{
+	  __sigmask (SIGALRM), 0, 0,
+	  &restart_itimer,
+	};
+      __mutex_lock (&_hurd_siglock);
+      if (! preempter.next && _hurdsig_preempters != &preempter)
 	{
-	  static struct hurd_signal_preempt preempt =
-	    { preempt_sigalrm, 0, 0, NULL };
-	  _hurd_signal_preempt[SIGALRM] = &preempt;
+	  preempter.next = _hurdsig_preempters;
+	  _hurdsig_preempters = &preempter;
 	}
+      __mutex_unlock (&_hurd_siglock);
 
       if (_hurd_itimer_port == MACH_PORT_NULL)
 	{
@@ -170,7 +199,7 @@ setitimer_locked (const struct itimerval *new, struct itimerval *old,
 					 &_hurd_itimer_thread_stack_size))
 	    {
 	      __thread_terminate (_hurd_itimer_thread);
-	      _hurd_itimer_thread = MACH_PORT_NULL;	  
+	      _hurd_itimer_thread = MACH_PORT_NULL;
 	      goto out;
 	    }
 	  _hurd_itimer_thread_suspended = 1;
@@ -293,25 +322,6 @@ DEFUN(__setitimer, (which, new, old),
   __spin_lock (&_hurd_itimer_lock);
   return setitimer_locked (new, old, crit);
 }
-
-static sighandler_t
-preempt_sigalrm (thread_t thread, int signo, long int sigcode, int sigerror)
-{
-  struct itimerval it;
-
-  if (thread != _hurd_sigthread || signo != SIGALRM || sigcode != 0)
-    /* Too much monkey business.  */
-    return SIG_DFL;
-
-  /* Either reload or disable the itimer.  */
-  __spin_lock (&_hurd_itimer_lock);
-  it = _hurd_itimerval;
-  it.it_value = it.it_interval;
-  setitimer_locked (&it, NULL, NULL);
-
-  /* Continue with normal delivery of SIGALRM.  */
-  return SIG_DFL;
-}
 
 static void
 fork_itimer (void)