Wed Jan 3 20:23:42 1996 Roland McGrath <roland@churchy.gnu.ai.mit.edu> cvs/libc-960104

	* hurd/catch-signal.c: New file.

	* hurd/intr-msg.c: When restarting RPC, fetch a new reply port.

	* hurd/hurdsig.c: Use new hurdfault.h interface.
	(abort_all_rpcs): Mutate return value to EINTR in threads whose
	replies we will wait for.

	* hurd/hurdkill.c (_hurd_sig_post): When doing pgrp, make sure we
	do ourselves last.

Wed Jan  3 19:17:10 1996  Miles Bader  <miles@gnu.ai.mit.edu>

	* sysdeps/mach/hurd/access.c (__access): Put the uid/gid arguments
	to auth_makeauth() in the right order.

Wed Jan  3 17:19:04 1996  Roland McGrath  <roland@churchy.gnu.ai.mit.edu>

	* sysdeps/generic/strsep.c: Rewritten.

	* sysdeps/mach/hurd/fork.c: Use a different workaround for the
 	suspended page fault deadlock kernel bug: thread_abort our signal
 	thread first thing after proc_dostop.

	* sysdeps/mach/hurd/setgid.c: Rewrote gid frobnication to
	recognize rootness properly.

	* hurd/hurdsig.c: Use new signal preemption interface.

3 files changed, 155 insertions, 33 deletions

diff --git a/hurd/catch-signal.c b/hurd/catch-signal.c
new file mode 100644
index 0000000000..3e8ee6c7e2
--- /dev/null
+++ b/hurd/catch-signal.c
@@ -0,0 +1,87 @@
+/* Convenience function to catch expected signals during an operation.
+Copyright (C) 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
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <hurd/signal.h>
+#include <hurd/sigpreempt.h>
+#include <string.h>
+#include <assert.h>
+
+error_t
+hurd_catch_signal (sigset_t sigset,
+		   unsigned long int first, unsigned long int last,
+		   error_t (*operate) (struct hurd_signal_preempter *),
+		   sighandler_t handler)
+{
+  jmp_buf buf;
+  void throw (int signo, long int sigcode, struct sigcontext *scp)
+    { longjmp (buf, scp->sc_error ?: EGRATUITOUS); }
+
+  struct hurd_signal_preempter preempter =
+    {
+      sigset, first, last,
+      NULL, handler == SIG_ERR ? (sighandler_t) &throw : handler,
+    };
+
+  struct hurd_sigstate *const ss = _hurd_self_sigstate ();
+  error_t error;
+
+  if (handler == SIG_ERR)
+    /* Not our handler; don't bother saving state.  */
+    error = 0;
+  else
+    /* This returns again with nonzero value when we preempt a signal.  */
+    error = setjmp (buf);
+
+  if (error == 0)
+    {
+      /* Install a signal preempter for the thread.  */
+      __spin_lock (&ss->lock);
+      preempter.next = ss->preempters;
+      ss->preempters = &preempter;
+      __spin_unlock (&ss->lock);
+
+      /* Try the operation that might crash.  */
+      (*operate) (&preempter);
+    }
+
+  /* Either FUNCTION completed happily and ERROR is still zero, or it hit
+     an expected signal and `throw' made setjmp return the signal error
+     code in ERROR.  Now we can remove the preempter and return.  */
+
+  __spin_lock (&ss->lock);
+  assert (ss->preempters == &preempter);
+  ss->preempters = preempter.next;
+  __spin_unlock (&ss->lock);
+
+  return error;
+}
+
+
+error_t
+hurd_safe_memset (void *dest, int byte, size_t nbytes)
+{
+  error_t operate (struct hurd_signal_preempter *preempter)
+    {
+      memset (dest, byte, nbytes);
+      return 0;
+    }
+  return hurd_catch_signal (sigmask (SIGBUS) | sigmask (SIGSEGV),
+			    (vm_address_t) dest, (vm_address_t) dest + nbytes,
+			    &operate, SIG_ERR);
+}
diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c
index 290dba825e..6085ab14cf 100644
--- a/hurd/hurdsig.c
+++ b/hurd/hurdsig.c
@@ -121,8 +121,9 @@ _hurd_thread_sigstate (thread_t thread)
 #include "thread_state.h"
 #include <hurd/msg_server.h>
 #include <hurd/msg_reply.h>	/* For __msg_sig_post_reply.  */
-#include <assert.h>
 #include <hurd/interrupt.h>
+#include <assert.h>
+#include <unistd.h>
 
 int _hurd_core_limit;	/* XXX */
 
@@ -216,12 +217,9 @@ interrupted_reply_port_location (struct machine_thread_all_state *thread_state,
   mach_port_t *portloc = (mach_port_t *) __hurd_threadvar_location_from_sp
     (_HURD_THREADVAR_MIG_REPLY, (void *) thread_state->basic.SP);
 
-  if (sigthread && _hurdsig_catch_fault (SIGSEGV))
-    {
-      assert (_hurdsig_fault_sigcode == (long int) portloc);
-      /* Faulted trying to read the stack.  */
-      return NULL;
-    }
+  if (sigthread && _hurdsig_catch_memory_fault (portloc))
+    /* Faulted trying to read the stack.  */
+    return NULL;
 
   /* Fault now if this pointer is bogus.  */
   *(volatile mach_port_t *) portloc = *portloc;
@@ -363,9 +361,9 @@ abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live)
   reply_ports = alloca (nthreads * sizeof *reply_ports);
 
   nthreads = 0;
-  for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
+  for (ss = _hurd_sigstates; ss != NULL; ss = ss->next, ++nthreads)
     if (ss->thread == _hurd_msgport_thread)
-      reply_ports[nthreads++] = MACH_PORT_NULL;
+      reply_ports[nthreads] = MACH_PORT_NULL;
     else
       {
 	int state_changed;
@@ -374,15 +372,26 @@ abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live)
 	/* Abort any operation in progress with interrupt_operation.
 	   Record the reply port the thread is waiting on.
 	   We will wait for all the replies below.  */
-	reply_ports[nthreads++] = _hurdsig_abort_rpcs (ss, signo, 1,
-						       state, &state_changed,
-						       NULL);
-	if (state_changed && live)
-	  /* Aborting the RPC needed to change this thread's state,
-	     and it might ever run again.  So write back its state.  */
-	  __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR,
-			      (natural_t *) &state->basic,
-			      MACHINE_THREAD_STATE_COUNT);
+	reply_ports[nthreads] = _hurdsig_abort_rpcs (ss, signo, 1,
+						     state, &state_changed,
+						     NULL);
+	if (live)
+	  {
+	    if (reply_ports[nthreads] != MACH_PORT_NULL)
+	      {
+		/* We will wait for the reply to this RPC below, so the
+		   thread must issue a new RPC rather than waiting for the
+		   reply to the one it sent.  */
+		state->basic.SYSRETURN = EINTR;
+		state_changed = 1;
+	      }
+	    if (state_changed)
+	      /* Aborting the RPC needed to change this thread's state,
+		 and it might ever run again.  So write back its state.  */
+	      __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR,
+				  (natural_t *) &state->basic,
+				  MACHINE_THREAD_STATE_COUNT);
+	  }
       }
 
   /* Wait for replies from all the successfully interrupted RPCs.  */
@@ -744,10 +753,8 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss,
 
 	    mach_port_t *loc;
 
-	    if (_hurdsig_catch_fault (SIGSEGV))
+	    if (_hurdsig_catch_memory_fault (ss->context))
 	      {
-		assert (_hurdsig_fault_sigcode >= (long int) ss->context &&
-			_hurdsig_fault_sigcode < (long int) (ss->context + 1));
 		/* We faulted reading the thread's stack.  Forget that
 		   context and pretend it wasn't there.  It almost
 		   certainly crash if this handler returns, but that's it's
@@ -1176,14 +1183,34 @@ text_set_element (_hurd_reauth_hook, reauth_proc);
 const char *
 _hurdsig_getenv (const char *variable)
 {
-  if (_hurdsig_catch_fault (SIGSEGV))
+  if (_hurdsig_catch_memory_fault (__environ))
     /* We bombed in getenv.  */
     return NULL;
   else
     {
-      const char *value = getenv (variable);
-      /* Fault now if VALUE is a bogus string.  */
-      (void) strlen (value);
+      const size_t len = strlen (variable);
+      char *value = NULL;
+      char *volatile *ep = __environ;
+      while (*ep)
+	{
+	  const char *p = *ep;
+	  _hurdsig_fault_preempter.first = (long int) p;
+	  _hurdsig_fault_preempter.last = VM_MAX_ADDRESS;
+	  if (! strncmp (p, variable, len) && p[len] == '=')
+	    {
+	      char *value;
+	      size_t valuelen;
+	      p += len + 1;
+	      valuelen = strlen (p);
+	      _hurdsig_fault_preempter.last = (long int) (p + valuelen);
+	      value = malloc (++valuelen);
+	      if (value)
+		memcpy (value, p, valuelen);
+	      break;
+	    }
+	  _hurdsig_fault_preempter.first = (long int) ++ep;
+	  _hurdsig_fault_preempter.last = (long int) (ep + 1);
+	}
       _hurdsig_end_catch_fault ();
       return value;
     }
diff --git a/hurd/intr-msg.c b/hurd/intr-msg.c
index 41f43e1e28..9362731240 100644
--- a/hurd/intr-msg.c
+++ b/hurd/intr-msg.c
@@ -1,5 +1,5 @@
 /* Replacement for mach_msg used in interruptible Hurd RPCs.
-Copyright (C) 1995 Free Software Foundation, Inc.
+Copyright (C) 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
@@ -19,6 +19,7 @@ Cambridge, MA 02139, USA.  */
 
 #include <mach.h>
 #include <mach/mig_errors.h>
+#include <mach/mig_support.h>
 #include <hurd/signal.h>
 
 #include "intr-msg.h"
@@ -45,7 +46,7 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
      return EINTR when some other thread gets a signal, in which case we
      want to restart our call.  */
   ss->intr_port = msg->msgh_remote_port;
-  
+
   /* A signal may arrive here, after intr_port is set, but before
      the mach_msg system call.  The signal handler might do an
      interruptible RPC, and clobber intr_port; then it would not be
@@ -58,12 +59,12 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
 
   if (ss->cancel)
     {
-      err = EINTR;
       ss->cancel = 0;
+      return EINTR;
     }
-  else 
-    err = INTR_MSG_TRAP (msg, option, send_size,
-			 rcv_size, rcv_name, timeout, notify);
+
+  err = INTR_MSG_TRAP (msg, option, send_size,
+		       rcv_size, rcv_name, timeout, notify);
 
   switch (err)
     {
@@ -83,7 +84,14 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
 	   signal thread will have cleared SS->intr_port.
 	   Since it's not cleared, the signal was for another thread,
 	   or SA_RESTART is set.  Restart the interrupted call.  */
-	goto message;
+	{
+	restart:
+	  if (rcv_name != MACH_PORT_NULL)
+	    /* Make sure we have a valid reply port.  The one we were using
+	       may have been destroyed by interruption.  */
+	    msg->msgh_local_port = rcv_name = __mig_get_reply_port ();
+	  goto message;
+	}
       /* FALLTHROUGH */
 
     case MACH_RCV_PORT_DIED:
@@ -139,7 +147,7 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
 	      if (ss->intr_port != MACH_PORT_NULL)
 		/* Nope; repeat the RPC.
 		   XXX Resources moved? */
-		goto message;
+		goto restart;
 	      else
 		/* The EINTR return indicates cancellation, so clear the
                    flag.  */