From: Miles Bader <miles@gnu.ai.mit.edu>

	* gnu-nat.c, gnu-nat.h, msg.defs, exc_request.defs, i386gnu-nat.c,
	msg_reply.defs, notify.defs, process_reply.defs, reply_mig_hack.awk,
	config/nm-gnu.h, config/i386/{i386gnu.mh, i386gnu.mt, nm-gnu.h,
	m-i386gnu.h, xm-i386gnu.h}: New files for GNU hurd.

1 files changed, 2814 insertions, 0 deletions

diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
new file mode 100644
index 00000000000..2d9cbed9f9d
--- /dev/null
+++ b/gdb/gnu-nat.c
@@ -0,0 +1,2814 @@
+/* Interface GDB to the GNU Hurd
+   Copyright (C) 1992, 1995, 1996 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   Some code and ideas from m3-nat.c by Jukka Virtanen <jtv@hut.fi>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+*/
+
+#include <stdio.h>
+#include <errno.h>
+#include <signal.h>
+#include <assert.h>
+#include <setjmp.h>
+#include <limits.h>
+#include <sys/ptrace.h>
+
+/* We include this because we don't need the access macros and they conflict
+   with gdb's definitions (ick).  This is very non standard!  */
+#include <waitflags.h>
+
+#include <mach.h>
+#include <mach/message.h>
+#include <mach/notify.h>
+#include <mach_error.h>
+#include <mach/exception.h>
+#include <mach/vm_attributes.h>
+
+#include <hurd/process.h>
+#include <hurd/process_request.h>
+#include <hurd/msg.h>
+#include <hurd/msg_request.h>
+#include <hurd/signal.h>
+#include <hurd/interrupt.h>
+#include <hurd/sigpreempt.h>
+
+#include "defs.h"
+#include "inferior.h"
+#include "symtab.h"
+#include "value.h"
+#include "language.h"
+#include "target.h"
+#include "wait.h"
+#include "gdbcmd.h"
+#include "gdbcore.h"
+
+#include "gnu-nat.h"
+
+#include "exc_request_S.h"
+#include "notify_S.h"
+#include "process_reply_S.h"
+#include "msg_reply_S.h"
+
+#include "exc_request_U.h"
+#include "msg_U.h"
+
+static process_t proc_server = MACH_PORT_NULL;
+
+/* If we've sent a proc_wait_request to the proc server, the pid of the
+   process we asked about.  We can only ever have one outstanding.  */
+int proc_wait_pid = 0;
+
+/* The number of wait requests we've sent, and expect replies from.  */
+int proc_waits_pending = 0;
+
+int gnu_debug_flag = 0;
+
+/* Forward decls */
+
+extern struct target_ops gnu_ops;
+
+struct inf *make_inf ();
+void inf_clear_wait (struct inf *inf);
+void inf_cleanup (struct inf *inf);
+void inf_startup (struct inf *inf, int pid, task_t task);
+int inf_update_suspends (struct inf *inf);
+void inf_set_task (struct inf *inf, task_t port);
+void inf_validate_procs (struct inf *inf);
+void inf_steal_exc_ports (struct inf *inf);
+void inf_restore_exc_ports (struct inf *inf);
+int inf_update_procs (struct inf *inf);
+struct proc *inf_tid_to_proc (struct inf *inf, int tid);
+inline void inf_set_threads_resume_sc (struct inf *inf, struct proc
+				       *run_thread, int run_others);
+inline int inf_set_threads_resume_sc_for_signal_thread (struct inf *inf);
+inline void inf_suspend (struct inf *inf);
+inline void inf_resume (struct inf *inf);
+void inf_set_step_thread (struct inf *inf, struct proc *proc);
+void inf_detach (struct inf *inf);
+void inf_attach (struct inf *inf, int pid);
+void inf_signal (struct inf *inf, enum target_signal sig);
+
+#define inf_debug(_inf, msg, args...) \
+  do { struct inf *__inf = (_inf); \
+       debug ("{inf %d %p}: " msg, __inf->pid, __inf , ##args); } while (0)
+
+struct proc *make_proc (struct inf *inf, mach_port_t port, int tid);
+struct proc *_proc_free (struct proc *proc);
+int proc_update_sc (struct proc *proc);
+void proc_abort (struct proc *proc, int force);
+thread_state_t proc_get_state (struct proc *proc, int force);
+error_t proc_get_exception_port (struct proc *proc, mach_port_t *port);
+error_t proc_set_exception_port (struct proc *proc, mach_port_t port);
+static mach_port_t _proc_get_exc_port (struct proc *proc);
+void proc_steal_exc_port (struct proc *proc, mach_port_t exc_port);
+void proc_restore_exc_port (struct proc *proc);
+int proc_trace (struct proc *proc, int set);
+char *proc_string (struct proc *proc);
+
+/* Evaluate RPC_EXPR in a scope with the variables MSGPORT and REFPORT bound
+   to INF's msg port and task port respectively.  If it has no msg port,
+   EIEIO is returned.  INF must refer to a running process!  */
+#define INF_MSGPORT_RPC(inf, rpc_expr) \
+  HURD_MSGPORT_RPC (proc_getmsgport (proc_server, inf->pid, &msgport), \
+		    (refport = inf->task->port, 0), 0, \
+		    msgport ? (rpc_expr) : EIEIO)
+
+/* Like INF_MSGPORT_RPC, but will also resume the signal thread to ensure
+   there's someone around to deal with the RPC (and resuspend things
+   afterwards).  This effects INF's threads' resume_sc count.  */
+#define INF_RESUME_MSGPORT_RPC(inf, rpc_expr) \
+  (inf_set_threads_resume_sc_for_signal_thread (inf) \
+   ? ({ error_t __e; \
+	inf_resume (inf); \
+	__e = INF_MSGPORT_RPC (inf, rpc_expr); \
+	inf_suspend (inf); \
+	__e; }) \
+   : EIEIO)
+
+#define MIG_SERVER_DIED EMIG_SERVER_DIED /* XXX */
+
+/* The state passed by an exception message.  */
+struct exc_state
+{
+  int exception;		/* The exception code */
+  int code, subcode;
+  mach_port_t handler;		/* The real exception port to handle this. */
+  mach_port_t reply;		/* The reply port from the exception call. */
+};
+
+/* The results of the last wait an inf did. */
+struct inf_wait
+{
+  struct target_waitstatus status; /* The status returned to gdb.  */
+  struct exc_state exc;		/* The exception that caused us to return. */
+  struct proc *thread;		/* The thread in question.  */
+  int suppress;			/* Something trivial happened.  */
+};
+
+/* The state of an inferior.  */
+struct inf
+{
+  /* Fields describing the current inferior.  */
+
+  struct proc *task;		/* The mach task.   */
+  struct proc *threads;		/* A linked list of all threads in TASK.  */
+
+  /* True if THREADS needn't be validated by querying the task.  We assume that
+     we and the task in question are the only ones frobbing the thread list,
+     so as long as we don't let any code run, we don't have to worry about
+     THREADS changing.  */
+  int threads_up_to_date;
+
+  pid_t pid;			/* The real system PID. */
+
+  struct inf_wait wait;		/* What to return from target_wait.  */
+
+  /* One thread proc in INF may be in `single-stepping mode'.  This is it.  */
+  struct proc *step_thread;
+
+  /* The thread we think is the signal thread.  */
+  struct proc *signal_thread;
+
+  mach_port_t event_port;	/* Where we receive various msgs.  */
+
+  /* True if we think at least one thread in the inferior could currently be
+     running.  */
+  int running : 1;
+
+  /* True if the process has stopped (in the proc server sense).  Note that
+     since a proc server `stop' leaves the signal thread running, the inf can
+     be RUNNING && STOPPED...  */
+  int stopped : 1;
+
+  /* True if the inferior is traced.  */
+  int traced : 1;
+
+  /* True if we shouldn't try waiting for the inferior, usually because we
+     can't for some reason.  */
+  int no_wait : 1;
+
+  /* When starting a new inferior, we don't try to validate threads until all
+     the proper execs have been done.  This is a count of how many execs we
+     expect to happen.  */
+  unsigned pending_execs;
+
+  /* Fields describing global state */
+
+  /* The task suspend count used when gdb has control.  This is normally 1 to
+     make things easier for us, but sometimes (like when attaching to vital
+     system servers) it may be desirable to let the task continue to run
+     (pausing individual threads as necessary).  */
+  int pause_sc;
+
+  /* The initial values used for the run_sc and pause_sc of newly discovered
+     threads -- see the definition of those fields in struct proc.  */
+  int default_thread_run_sc;
+  int default_thread_pause_sc;
+
+  /* True if the process should be traced when started/attached.  Newly
+     started processes *must* be traced at first to exec them properly, but
+     if this is false, tracing is turned off as soon it has done so.  */
+  int want_signals;
+
+  /* True if exceptions from the inferior process should be trapped.  This
+     must be on to use breakpoints.  */
+  int want_exceptions;
+};
+
+int __proc_pid (struct proc *proc)
+{
+  return proc->inf->pid;
+}
+
+/* Update PROC's real suspend count to match it's desired one.  Returns true
+   if we think PROC is now in a runnable state.  */
+int
+proc_update_sc (struct proc *proc)
+{
+  int running;
+  int err =  0;
+  int delta = proc->sc - proc->cur_sc;
+
+  if (delta)
+    proc_debug (proc, "sc: %d --> %d", proc->cur_sc, proc->sc);
+
+  if (proc->sc == 0 && proc->state_changed)
+    /* Since PROC may start running, we must write back any state changes. */
+    {
+      assert (proc_is_thread (proc));
+      proc_debug (proc, "storing back changed thread state");
+      err = thread_set_state (proc->port, THREAD_STATE_FLAVOR,
+			      &proc->state, THREAD_STATE_SIZE);
+      if (! err)
+	proc->state_changed = 0;
+    }
+
+  if (delta > 0)
+    while (delta-- > 0 && !err)
+      if (proc_is_task (proc))
+	err = task_suspend (proc->port);
+      else
+	err = thread_suspend (proc->port);
+  else
+    while (delta++ < 0 && !err)
+      if (proc_is_task (proc))
+	err = task_resume (proc->port);
+      else
+	err = thread_resume (proc->port);
+
+  if (! err)
+    proc->cur_sc = proc->sc;
+
+  /* If we got an error, then the task/thread has disappeared.  */
+  running = !err && proc->sc == 0;
+
+  proc_debug (proc, "is %s", err ? "dead" : running ? "running" : "suspended");
+  if (err)
+    proc_debug (proc, "err = %s", strerror (err));
+
+  if (running)
+    {
+      proc->aborted = 0;
+      proc->state_valid = proc->state_changed = 0;
+      proc->fetched_regs = 0;
+    }
+
+  return running;
+}
+
+/* Thread_abort is called on PROC if needed.  PROC must be a thread proc.
+   If PROC is deemed `precious', then nothing is done unless FORCE is true.
+   In particular, a thread is precious if it's running (in which case forcing
+   it includes suspending it first), or if it has an exception pending.  */
+void
+proc_abort (struct proc *proc, int force)
+{
+  assert (proc_is_thread (proc));
+
+  if (! proc->aborted)
+    {
+      struct inf *inf = proc->inf;
+      int running = (proc->cur_sc == 0 && inf->task->cur_sc == 0);
+
+      if (running && force)
+	{
+	  proc->sc = 1;
+	  inf_update_suspends (proc->inf);
+	  running = 0;
+	  warning ("Stopped %s.", proc_string (proc));
+	}
+      else if (proc == inf->wait.thread && inf->wait.exc.reply && !force)
+	/* An exception is pending on PROC, which don't mess with.  */
+	running = 1;
+
+      if (! running)
+	/* We only abort the thread if it's not actually running.  */
+	{
+	  thread_abort (proc->port);
+	  proc_debug (proc, "aborted");
+	  proc->aborted = 1;
+	}
+      else
+	proc_debug (proc, "not aborting");
+    }
+}
+
+/* Make sure that the state field in PROC is up to date, and return a pointer
+   to it, or 0 if something is wrong.  If WILL_MODIFY is true, makes sure
+   that the thread is stopped and aborted first, and sets the state_changed
+   field in PROC to true.  */
+thread_state_t
+proc_get_state (struct proc *proc, int will_modify)
+{
+  int was_aborted = proc->aborted;
+
+  proc_debug (proc, "updating state info%s",
+	      will_modify ? " (with intention to modify)" : "");
+
+  proc_abort (proc, will_modify);
+
+  if (! was_aborted && proc->aborted)
+    /* PROC's state may have changed since we last fetched it.  */
+    proc->state_valid = 0;
+
+  if (! proc->state_valid)
+    {
+      mach_msg_type_number_t state_size = THREAD_STATE_SIZE;
+      error_t err =
+	thread_get_state (proc->port, THREAD_STATE_FLAVOR,
+			  &proc->state, &state_size);
+      proc_debug (proc, "getting thread state");
+      proc->state_valid = !err;
+    }
+
+  if (proc->state_valid)
+    {
+      if (will_modify)
+	proc->state_changed = 1;
+      return &proc->state;
+    }
+  else
+    return 0;
+}
+
+error_t
+proc_get_exception_port (struct proc *proc, mach_port_t *port)
+{
+  if (proc_is_task (proc))
+    return task_get_exception_port (proc->port, port);
+  else
+    return thread_get_exception_port (proc->port, port);
+}
+
+error_t
+proc_set_exception_port (struct proc *proc, mach_port_t port)
+{
+  proc_debug (proc, "setting exception port: %d", port);
+  if (proc_is_task (proc))
+    return task_set_exception_port (proc->port, port);
+  else
+    return thread_set_exception_port (proc->port, port);
+}
+
+/* Get PROC's exception port, cleaning up a bit if proc has died.  */
+static mach_port_t
+_proc_get_exc_port (struct proc *proc)
+{
+  mach_port_t exc_port;
+  error_t err = proc_get_exception_port (proc, &exc_port);
+
+  if (err)
+    /* PROC must be dead.  */
+    {
+      if (proc->exc_port)
+	mach_port_deallocate (mach_task_self (), proc->exc_port);
+      proc->exc_port = MACH_PORT_NULL;
+      if (proc->saved_exc_port)
+	mach_port_deallocate (mach_task_self (), proc->saved_exc_port);
+      proc->saved_exc_port = MACH_PORT_NULL;
+    }
+
+  return exc_port;
+}
+
+/* Replace PROC's exception port with EXC_PORT, unless it's already been
+   done.  Stash away any existing exception port so we can restore it later. */
+void
+proc_steal_exc_port (struct proc *proc, mach_port_t exc_port)
+{
+  mach_port_t cur_exc_port = _proc_get_exc_port (proc);
+
+  if (cur_exc_port)
+    {
+      error_t err;
+
+      proc_debug (proc, "inserting exception port: %d", exc_port);
+
+      if (cur_exc_port != exc_port)
+	/* Put in our exception port.  */
+	err = proc_set_exception_port (proc, exc_port);
+
+      if (err || cur_exc_port == proc->exc_port)
+	/* We previously set the exception port, and it's still set.  So we
+	   just keep the old saved port which is what the proc set.  */
+	{
+	  if (cur_exc_port)
+	    mach_port_deallocate (mach_task_self (), cur_exc_port);
+	}
+      else
+	/* Keep a copy of PROC's old exception port so it can be restored. */
+	{
+	  if (proc->saved_exc_port)
+	    mach_port_deallocate (mach_task_self (), proc->saved_exc_port);
+	  proc->saved_exc_port = cur_exc_port;
+	}
+
+      proc_debug (proc, "saved exception port: %d", proc->saved_exc_port);
+
+      if (!err)
+	proc->exc_port = exc_port;
+      else
+	warning ("Error setting exception port for %s: %s",
+		 proc_string (proc), strerror (err));
+    }
+}
+
+/* If we previously replaced PROC's exception port, put back what we found
+   there at the time, unless *our* exception port has since be overwritten,
+   in which case who knows what's going on.  */
+void
+proc_restore_exc_port (struct proc *proc)
+{
+  mach_port_t cur_exc_port = _proc_get_exc_port (proc);
+
+  if (cur_exc_port)
+    {
+      error_t err = 0;
+
+      proc_debug (proc, "restoring real exception port");
+
+      if (proc->exc_port == cur_exc_port)
+	/* Our's is still there.  */
+	err = proc_set_exception_port (proc, proc->saved_exc_port);
+
+      if (proc->saved_exc_port)
+	mach_port_deallocate (mach_task_self (), proc->saved_exc_port);
+      proc->saved_exc_port = MACH_PORT_NULL;
+
+      if (!err)
+	proc->exc_port = MACH_PORT_NULL;
+      else
+	warning ("Error setting exception port for %s: %s",
+		 proc_string (proc), strerror (err));
+    }
+}
+
+/* Turns hardware tracing in PROC on or off when SET is true or fals,
+   respectively.  Returns true on success.  */
+int
+proc_trace (struct proc *proc, int set)
+{
+  thread_state_t state = proc_get_state (proc, 1);
+
+  if (! state)
+    return 0;			/* the thread must be dead.  */
+
+  proc_debug (proc, "tracing %s", set ? "on" : "off");
+  
+  if (set)
+    {
+      /* XXX We don't get the exception unless the thread has its own
+	 exception port???? */
+      if (proc->exc_port == MACH_PORT_NULL)
+	proc_steal_exc_port (proc, proc->inf->event_port);
+      THREAD_STATE_SET_TRACED (state);
+    }
+  else
+    THREAD_STATE_CLEAR_TRACED (state);
+
+  return 1;
+}
+
+/* A variable from which to assign new TIDs.  */
+static int next_thread_id = 1;
+
+/* Returns a new proc structure with the given fields.  Also adds a
+   notification for PORT becoming dead to be sent to INF's notify port.  */
+struct proc *
+make_proc (struct inf *inf, mach_port_t port, int tid)
+{
+  error_t err;
+  mach_port_t prev_port = MACH_PORT_NULL;
+  struct proc *proc = malloc (sizeof (struct proc));
+
+  proc->port = port;
+  proc->tid = tid;
+  proc->inf = inf;
+  proc->next = 0;
+  proc->saved_exc_port = MACH_PORT_NULL;
+  proc->exc_port = MACH_PORT_NULL;
+  proc->sc = 0;
+  proc->cur_sc = 0;
+  proc->run_sc = inf->default_thread_run_sc;
+  proc->pause_sc = inf->default_thread_pause_sc;
+  proc->resume_sc = proc->run_sc;
+  proc->aborted = 0;
+  proc->state_valid = 0;
+  proc->state_changed = 0;
+
+  proc_debug (proc, "is new");
+
+  /* Get notified when things die.  */
+  err =
+    mach_port_request_notification (mach_task_self(), port,
+				    MACH_NOTIFY_DEAD_NAME, 1,
+				    inf->event_port,
+				    MACH_MSG_TYPE_MAKE_SEND_ONCE,
+				    &prev_port);
+  if (err)
+    warning ("Couldn't request notification for port %d: %s",
+	     port, strerror (err));
+  else
+    {
+      proc_debug (proc, "notifications to: %d", inf->event_port);
+      if (prev_port != MACH_PORT_NULL)
+	mach_port_deallocate (mach_task_self (), prev_port);
+    }
+
+  if (inf->want_exceptions)
+    if (proc_is_task (proc))
+      /* Make the task exception port point to us.  */
+      proc_steal_exc_port (proc, inf->event_port);
+    else
+      /* Just clear thread exception ports -- they default to the task one.  */
+      proc_steal_exc_port (proc, MACH_PORT_NULL);
+
+  return proc;
+}
+
+/* Frees PROC and any resources it uses, and returns the value of PROC's next
+   field.  */
+struct proc *
+_proc_free (struct proc *proc)
+{
+  struct inf *inf = proc->inf;
+  struct proc *next = proc->next;
+
+  proc_debug (proc, "freeing...");
+
+  if (proc == inf->step_thread)
+    /* Turn off single stepping.  */
+    inf_set_step_thread (inf, 0);
+  if (proc == inf->wait.thread)
+    inf_clear_wait (inf);
+  if (proc == inf->signal_thread)
+    inf->signal_thread = 0;
+
+  if (proc->port != MACH_PORT_NULL)
+    {
+      if (proc->exc_port != MACH_PORT_NULL)
+	/* Restore the original exception port.  */
+	proc_restore_exc_port (proc);
+      if (proc->cur_sc != 0)
+	/* Resume the thread/task.  */
+	{
+	  proc->sc = 0;
+	  proc_update_sc (proc);
+	}
+      mach_port_deallocate (mach_task_self (), proc->port);
+    }
+
+  free (proc);
+  return next;
+}
+
+struct inf *make_inf ()
+{
+  struct inf *inf = malloc (sizeof (struct inf));
+
+  if (!inf)
+    return 0;
+
+  inf->task = 0;
+  inf->threads = 0;
+  inf->threads_up_to_date = 0;
+  inf->pid = 0;
+  inf->wait.status.kind = TARGET_WAITKIND_SPURIOUS;
+  inf->wait.thread = 0;
+  inf->wait.exc.handler = MACH_PORT_NULL;
+  inf->wait.exc.reply = MACH_PORT_NULL;
+  inf->step_thread = 0;
+  inf->signal_thread = 0;
+  inf->event_port = MACH_PORT_NULL;
+  inf->stopped = 0;
+  inf->running = 0;
+  inf->traced = 0;
+  inf->no_wait = 0;
+  inf->pending_execs = 0;
+  inf->pause_sc = 1;
+  inf->default_thread_run_sc = 0;
+  inf->default_thread_pause_sc = 0;
+  inf->want_signals = 1;	/* By default */
+  inf->want_exceptions = 1;	/* By default */
+
+  return inf;
+}
+
+void
+inf_clear_wait (struct inf *inf)
+{
+  inf_debug (inf, "clearing wait");
+  inf->wait.status.kind = TARGET_WAITKIND_SPURIOUS;
+  inf->wait.thread = 0;
+  inf->wait.suppress = 0;
+  if (inf->wait.exc.handler != MACH_PORT_NULL)
+    {
+      mach_port_deallocate (mach_task_self (), inf->wait.exc.handler);
+      inf->wait.exc.handler = MACH_PORT_NULL;
+    }
+  if (inf->wait.exc.reply != MACH_PORT_NULL)
+    {
+      mach_port_deallocate (mach_task_self (), inf->wait.exc.reply);
+      inf->wait.exc.reply = MACH_PORT_NULL;
+    }
+}
+
+void
+inf_cleanup (struct inf *inf)
+{
+  inf_debug (inf, "cleanup");
+
+  inf_clear_wait (inf);
+
+  inf_set_task (inf, MACH_PORT_NULL);
+  inf->pid = 0;
+  inf->traced = 0;
+  inf->no_wait = 0;
+  inf->stopped = 0;
+  inf->running = 0;
+  inf->pending_execs = 0;
+
+  if (inf->event_port)
+    {
+      mach_port_destroy (mach_task_self (), inf->event_port);
+      inf->event_port = MACH_PORT_NULL;
+    }
+}
+
+void
+inf_startup (struct inf *inf, int pid, task_t task)
+{
+  error_t err;
+
+  inf_debug (inf, "startup: pid = %d, task = %d", pid, task);
+
+  inf_cleanup (inf);
+
+  /* Make the port on which we receive all events.  */
+  err = mach_port_allocate (mach_task_self (),
+			    MACH_PORT_RIGHT_RECEIVE, &inf->event_port);
+  if (err)
+    error ("Error allocating event port: %s", strerror (err));
+
+  /* Make a send right for it, so we can easily copy it for other people.  */
+  mach_port_insert_right (mach_task_self (), inf->event_port,
+			  inf->event_port, MACH_MSG_TYPE_MAKE_SEND);
+
+  if (inf->pause_sc)
+    task_suspend (task);
+
+  inf_set_task (inf, task); 
+
+  if (inf->task)
+    {
+      inf->pid = pid;
+      if (inf->pause_sc)
+	inf->task->sc = inf->task->cur_sc = 1; /* Reflect task_suspend above */
+    }
+}
+
+void 
+inf_set_task (struct inf *inf, mach_port_t port)
+{
+  struct proc *task = inf->task;
+
+  inf_debug (inf, "setting task: %d", port);
+
+  if (task && task->port != port)
+    {
+      inf->task = 0;
+      inf_validate_procs (inf);	/* Trash all the threads. */
+      _proc_free (task);	/* And the task. */
+    }
+
+  if (port != MACH_PORT_NULL)
+    {
+      inf->task = make_proc (inf, port, PROC_TID_TASK);
+      inf->threads_up_to_date = 0;
+    }
+}
+
+/* Validates INF's stopped field from the actual proc server state.  */
+static void
+inf_validate_stopped (struct inf *inf)
+{
+  char *noise;
+  mach_msg_type_number_t noise_len = 0;
+  struct procinfo *pi;
+  mach_msg_type_number_t pi_len = 0;
+  error_t err =
+    proc_getprocinfo (proc_server, inf->pid, 0,
+		      (procinfo_t *)&pi, &pi_len, &noise, &noise_len);
+
+  if (! err)
+    {
+      inf->stopped = !!(pi->state & PI_STOPPED);
+      vm_deallocate (mach_task_self (), (vm_address_t)pi, pi_len);
+      if (noise_len > 0)
+	vm_deallocate (mach_task_self (), (vm_address_t)noise, noise_len);
+    }
+}
+
+/* Validates INF's task suspend count.  */
+static void
+inf_validate_task_sc (struct inf *inf)
+{
+  struct task_basic_info info;
+  mach_msg_type_number_t info_len = TASK_BASIC_INFO_COUNT;
+  error_t err = task_info (inf->task->port, TASK_BASIC_INFO, &info, &info_len);
+  if (! err)
+    {
+      if (inf->task->cur_sc < info.suspend_count)
+	warning ("Pid %d is suspended; continuing will clear existing suspend count.", inf->pid);
+      inf->task->cur_sc = info.suspend_count;
+    }
+}
+
+/* Turns tracing for INF on or off, depending on ON, unless it already is.
+   If INF is running, the resume_sc count of INF's threads will be modified,
+   and the signal thread will briefly be run to change the trace state.  */
+void
+inf_set_traced (struct inf *inf, int on)
+{
+  if (on != inf->traced)
+    if (inf->task)
+      /* Make it take effect immediately.  */
+      {
+	error_t (*f)(mach_port_t, mach_port_t, int) =
+	  on ? msg_set_some_exec_flags : msg_clear_some_exec_flags;
+	error_t err =
+	  INF_RESUME_MSGPORT_RPC (inf, (*f)(msgport, refport, EXEC_TRACED));
+	if (err == EIEIO)
+	  warning ("Can't modify tracing state for pid %d: No signal thread",
+		   inf->pid);
+	else if (err)
+	  warning ("Can't modify tracing state for pid %d: %s",
+		   inf->pid, strerror (err));
+	else
+	  inf->traced = on;
+      }
+    else
+      inf->traced = on;
+}
+
+/* Makes all the real suspend count deltas of all the procs in INF match the
+   desired values.  Careful to always do thread/task suspend counts in the
+   safe order.  Returns true if at least one thread is thought to be running.*/
+int
+inf_update_suspends (struct inf *inf)
+{
+  struct proc *task = inf->task;
+  /* We don't have to update INF->threads even though we're iterating over it
+     because we'll change a thread only if it already has an existing proc
+     entry.  */
+
+  inf_debug (inf, "updating suspend counts");
+
+  if (task)
+    {
+      struct proc *thread;
+      int task_running = (task->sc == 0), thread_running = 0;
+
+      if (task->sc > task->cur_sc)
+	/* The task is becoming _more_ suspended; do before any threads.  */
+	task_running = proc_update_sc (task);
+
+      if (inf->pending_execs)
+	/* When we're waiting for an exec, things may be happening behind our
+	   back, so be conservative.  */
+	thread_running = 1;
+
+      /* Do all the thread suspend counts.  */
+      for (thread = inf->threads; thread; thread = thread->next)
+	thread_running |= proc_update_sc (thread);
+
+      if (task->sc != task->cur_sc)
+	/* We didn't do the task first, because we wanted to wait for the
+	   threads; do it now.  */
+	task_running = proc_update_sc (task);
+
+      inf_debug (inf, "%srunning...",
+		 (thread_running && task_running) ? "" : "not ");
+
+      inf->running = thread_running && task_running;
+
+      /* Once any thread has executed some code, we can't depend on the
+	 threads list any more.  */
+      if (inf->running)
+	inf->threads_up_to_date = 0;
+
+      return inf->running;
+    }
+
+  return 0;
+}
+
+/* Converts a GDB pid to a struct proc.  */
+struct proc *
+inf_tid_to_thread (struct inf *inf, int tid)
+{
+  struct proc *thread = inf->threads;
+  while (thread)
+    if (thread->tid == tid)
+      return thread;
+    else
+      thread = thread->next;
+  return 0;
+}
+
+/* Converts a thread port to a struct proc.  */
+struct proc *
+inf_port_to_thread (struct inf *inf, mach_port_t port)
+{
+  struct proc *thread = inf->threads;
+  while (thread)
+    if (thread->port == port)
+      return thread;
+    else
+      thread = thread->next;
+  return 0;
+}
+
+/* Make INF's list of threads be consistent with reality of TASK.  */
+void
+inf_validate_procs (struct inf *inf)
+{
+  int i;
+  thread_array_t threads;
+  unsigned num_threads;
+  struct proc *task = inf->task;
+
+  inf->threads_up_to_date = !inf->running;
+
+  if (task)
+    {
+      error_t err = task_threads (task->port, &threads, &num_threads);
+      inf_debug (inf, "fetching threads");
+      if (err)
+	/* TASK must be dead.  */
+	{
+	  task->port = MACH_PORT_NULL;
+	  _proc_free (task);
+	  task = inf->task = 0;
+	}
+    }
+
+  if (!task)
+    {
+      num_threads = 0;
+      inf_debug (inf, "no task");
+    }
+
+  {
+    unsigned search_start = 0;	/* Make things normally linear.  */
+    /* Which thread in PROCS corresponds to each task thread, & the task.  */
+    struct proc *matched[num_threads + 1];
+    /* The last thread in INF->threads, so we can add to the end.  */
+    struct proc *last = 0;
+    /* The current thread we're considering. */
+    struct proc *thread = inf->threads;
+
+    bzero (matched, sizeof (matched));
+
+    while (thread)
+      {
+	unsigned left;
+
+	for (i = search_start, left = num_threads; left; i++, left--)
+	  {
+	    if (i >= num_threads)
+	      i -= num_threads; /* I wrapped around.  */
+	    if (thread->port == threads[i])
+	      /* We already know about this thread.  */
+	      {
+		matched[i] = thread;
+		last = thread;
+		thread = thread->next;
+		search_start++;
+		break;
+	      }
+	  }
+
+	if (! left)
+	  {
+	    proc_debug (thread, "died!");
+	    thread->port = MACH_PORT_NULL;
+	    thread = _proc_free (thread); /* THREAD is dead.  */
+	    (last ? last->next : inf->threads) = thread;
+	  }
+      }
+
+    for (i = 0; i < num_threads; i++)
+      if (matched[i])
+	/* Throw away the duplicate send right.  */
+	mach_port_deallocate (mach_task_self (), threads[i]);
+      else
+	/* THREADS[I] is a thread we don't know about yet!  */
+	{
+	  thread = make_proc (inf, threads[i], next_thread_id++);
+	  (last ? last->next : inf->threads) = thread;
+	  last = thread;
+	  proc_debug (thread, "new thread: %d", threads[i]);
+	  add_thread (thread->tid); /* Tell GDB's generic thread code.  */
+	}
+
+    vm_deallocate(mach_task_self(),
+		  (vm_address_t)threads, (num_threads * sizeof(thread_t)));
+  }
+}
+
+/* Makes sure that INF's thread list is synced with the actual process.  */
+inline int
+inf_update_procs (struct inf *inf)
+{
+  if (! inf->task)
+    return 0;
+  if (! inf->threads_up_to_date)
+    inf_validate_procs (inf);
+  return !!inf->task;
+}
+
+/* Sets the resume_sc of each thread in inf.  That of RUN_THREAD is set to 0,
+   and others are set to their run_sc if RUN_OTHERS is true, and otherwise
+   their pause_sc.  */
+inline void 
+inf_set_threads_resume_sc (struct inf *inf,
+			   struct proc *run_thread, int run_others)
+{
+  struct proc *thread;
+  inf_update_procs (inf);
+  for (thread = inf->threads; thread; thread = thread->next)
+    if (thread == run_thread)
+      thread->resume_sc = 0;
+    else if (run_others)
+      thread->resume_sc = thread->run_sc;
+    else
+      thread->resume_sc = thread->pause_sc;
+}
+
+/* Cause INF to continue execution immediately; individual threads may still
+   be suspended (but their suspend counts will be updated).  */
+inline void
+inf_resume (struct inf *inf)
+{
+  struct proc *thread;
+
+  inf_update_procs (inf);
+
+  for (thread = inf->threads; thread; thread = thread->next)
+    thread->sc = thread->resume_sc;
+
+  if (inf->task)
+    inf->task->sc = 0;
+
+  inf_update_suspends (inf);
+}
+
+/* Cause INF to stop execution immediately; individual threads may still
+   be running.  */
+inline void
+inf_suspend (struct inf *inf)
+{
+  struct proc *thread;
+
+  inf_update_procs (inf);
+
+  for (thread = inf->threads; thread; thread = thread->next)
+    thread->sc = thread->pause_sc;
+
+  if (inf->task)
+    inf->task->sc = inf->pause_sc;
+
+  inf_update_suspends (inf);
+}
+
+/* INF has one thread PROC that is in single-stepping mode.  This functions
+   changes it to be PROC, changing any old step_thread to be a normal one.  A
+   PROC of 0 clears an any existing value.  */
+void
+inf_set_step_thread (struct inf *inf, struct proc *thread)
+{
+  assert (!thread || proc_is_thread (thread));
+
+  if (thread)
+    inf_debug (inf, "setting step thread: %d/%d", inf->pid, thread->tid);
+  else
+    inf_debug (inf, "clearing step thread");
+
+  if (inf->step_thread != thread)
+    {
+      if (inf->step_thread && inf->step_thread->port != MACH_PORT_NULL)
+	if (! proc_trace (inf->step_thread, 0))
+	  return;
+      if (thread && proc_trace (thread, 1))
+	inf->step_thread = thread;
+      else
+	inf->step_thread = 0;
+    }
+}
+
+/* Set up the thread resume_sc's so that only the signal thread is running
+   (plus whatever other thread are set to always run).  Returns true if we
+   did so, or false if we can't find a signal thread.  */
+inline int
+inf_set_threads_resume_sc_for_signal_thread (struct inf *inf)
+{
+  if (inf->signal_thread)
+    {
+      inf_set_threads_resume_sc (inf, inf->signal_thread, 0);
+      return 1;
+    }
+  else
+    return 0;
+}
+
+static void
+inf_update_signal_thread (struct inf *inf)
+{
+  /* XXX for now we assume that if there's a msgport, the 2nd thread is
+     the signal thread.  */
+  inf->signal_thread = inf->threads ? inf->threads->next : 0;
+}
+
+/* Detachs from INF's inferior task, letting it run once again...  */
+void
+inf_detach (struct inf *inf)
+{
+  struct proc *task = inf->task;
+
+  inf_debug (inf, "detaching...");
+
+  inf_clear_wait (inf);
+  inf_set_step_thread (inf, 0);
+
+  if (task)
+    {
+      struct proc *thread;
+
+      inf_set_traced (inf, 0);
+      if (inf->stopped)
+	inf_signal (inf, TARGET_SIGNAL_0);
+
+      proc_restore_exc_port (task);
+      task->sc = 0;
+
+      for (thread = inf->threads; thread; thread = thread->next)
+	{
+	  proc_restore_exc_port (thread);
+	  thread->sc = 0;
+	}
+
+      inf_update_suspends (inf);
+    }
+
+  inf_cleanup (inf);
+}
+
+/* Attaches INF to the process with process id PID, returning it in a suspended
+   state suitable for debugging.  */
+void
+inf_attach (struct inf *inf, int pid)
+{
+  error_t err;
+  task_t task;
+
+  inf_debug (inf, "attaching: %d", pid);
+
+  err = proc_pid2task (proc_server, pid, &task);
+  if (err)
+    error ("Error getting task for pid %d: %s", pid, strerror (err));
+
+  if (inf->pid)
+    inf_detach (inf);
+
+  inf_startup (inf, pid, task);
+}
+
+/* Makes sure that we've got our exception ports entrenched in the process. */
+void inf_steal_exc_ports (struct inf *inf)
+{
+  struct proc *thread;
+
+  inf_debug (inf, "stealing exception ports");
+
+  inf_set_step_thread (inf, 0);	/* The step thread is special. */
+
+  proc_steal_exc_port (inf->task, inf->event_port);
+  for (thread = inf->threads; thread; thread = thread->next)
+    proc_steal_exc_port (thread, MACH_PORT_NULL);
+}
+
+/* Makes sure the process has its own exception ports.  */
+void inf_restore_exc_ports (struct inf *inf)
+{
+  struct proc *thread;
+
+  inf_debug (inf, "restoring exception ports");
+
+  inf_set_step_thread (inf, 0);	/* The step thread is special. */
+
+  proc_restore_exc_port (inf->task);
+  for (thread = inf->threads; thread; thread = thread->next)
+    proc_restore_exc_port (thread);
+}
+
+/* Deliver signal SIG to INF.  If INF is stopped, delivering a signal, even
+   signal 0, will continue it.  INF is assumed to be in a paused state, and
+   the resume_sc's of INF's threads may be affected.  */
+void
+inf_signal (struct inf *inf, enum target_signal sig)
+{
+  error_t err = 0;
+  int host_sig = target_signal_to_host (sig);
+
+#define NAME target_signal_to_name (sig)
+
+  if (host_sig >= _NSIG)
+    /* A mach exception.  Exceptions are encoded in the signal space by
+       putting them after _NSIG; this assumes they're positive (and not
+       extremely large)!  */
+    {
+      struct inf_wait *w = &inf->wait;
+      if (w->status.kind == TARGET_WAITKIND_STOPPED
+	  && w->status.value.sig == sig
+	  && w->thread && !w->thread->aborted)
+	/* We're passing through the last exception we received.  This is
+	   kind of bogus, because exceptions are per-thread whereas gdb
+	   treats signals as per-process.  We just forward the exception to
+	   the correct handler, even it's not for the same thread as TID --
+	   i.e., we pretend it's global.  */
+	{
+	  struct exc_state *e = &w->exc;
+	  inf_debug (inf, "passing through exception:"
+		     " task = %d, thread = %d, exc = %d"
+		     ", code = %d, subcode = %d",
+		     w->thread->port, inf->task->port,
+		     e->exception, e->code, e->subcode);
+	  err =
+	    exception_raise_request (e->handler,
+				     e->reply, MACH_MSG_TYPE_MOVE_SEND_ONCE,
+				     w->thread->port, inf->task->port,
+				     e->exception, e->code, e->subcode);
+	}
+      else
+	warning ("Can't forward spontaneous exception (%s).", NAME);
+    }
+  else
+    /* A Unix signal.  */
+    if (inf->stopped)
+      /* The process is stopped an expecting a signal.  Just send off a
+	 request and let it get handled when we resume everything.  */
+      {
+	inf_debug (inf, "sending %s to stopped process", NAME);
+	err =
+	  INF_MSGPORT_RPC (inf,
+			   msg_sig_post_untraced_request (msgport,
+							  inf->event_port,
+							  MACH_MSG_TYPE_MAKE_SEND_ONCE,
+							  host_sig,
+							  refport));
+	if (! err)
+	  /* Posting an untraced signal automatically continues it.
+	     We clear this here rather than when we get the reply
+	     because we'd rather assume it's not stopped when it
+	     actually is, than the reverse.  */
+	  inf->stopped = 0;
+      }
+    else
+      /* It's not expecting it.  We have to let just the signal thread
+	 run, and wait for it to get into a reasonable state before we
+	 can continue the rest of the process.  When we finally resume the
+	 process the signal we request will be the very first thing that
+	 happens. */
+      {
+	inf_debug (inf, "sending %s to unstopped process (so resuming signal thread)", NAME);
+	err = 
+	  INF_RESUME_MSGPORT_RPC (inf,
+				  msg_sig_post_untraced (msgport,
+							 host_sig, refport));
+      }
+
+  if (err == EIEIO)
+    /* Can't do too much... */
+    warning ("Can't deliver signal %s: No signal thread.", NAME);
+  else if (err)
+    warning ("Delivering signal %s: %s", NAME, strerror (err));
+
+#undef NAME
+}
+
+/* The inferior used for all gdb target ops.  */
+struct inf *current_inferior = 0;
+
+/* The inferior being waited for by gnu_wait.  Since GDB is decidely not
+   multi-threaded, we don't bother to lock this.  */
+struct inf *waiting_inf;
+
+/* Wait for something to happen in the inferior, returning what in STATUS. */
+static int
+gnu_wait (int tid, struct target_waitstatus *status)
+{
+  struct msg {
+    mach_msg_header_t hdr;
+    mach_msg_type_t type;
+    int data[8000];
+  } msg;
+  error_t err;
+  struct proc *thread;
+  struct inf *inf = current_inferior;
+
+  waiting_inf = inf;
+
+  inf_debug (inf, "waiting for: %d", tid);
+
+ rewait:
+  if (proc_wait_pid != inf->pid && !inf->no_wait)
+    /* Always get information on events from the proc server.  */
+    {
+      inf_debug (inf, "requesting wait on pid %d", inf->pid);
+
+      if (proc_wait_pid)
+	/* The proc server is single-threaded, and only allows a single
+	   outstanding wait request, so we have to cancel the previous one. */
+	{
+	  inf_debug (inf, "cancelling previous wait on pid %d", proc_wait_pid);
+	  interrupt_operation (proc_server);
+	}
+
+      err =
+	proc_wait_request (proc_server, inf->event_port, inf->pid, WUNTRACED);
+      if (err)
+	warning ("wait request failed: %s", strerror (err));
+      else
+	{
+	  inf_debug (inf, "waits pending: %d", proc_waits_pending);
+	  proc_wait_pid = inf->pid;
+	  /* Even if proc_waits_pending was > 0 before, we still won't get
+	     any other replies, because it was either from a different INF,
+	     or a different process attached to INF -- and the event port,
+	     which is the wait reply port, changes when you switch processes.*/
+	  proc_waits_pending = 1;
+	}
+    }
+
+  inf_clear_wait (inf);
+
+  /* What can happen? (1) Dead name notification; (2) Exceptions arrive;
+     (3) wait reply from the proc server.  */
+
+  inf_debug (inf, "waiting for an event...");
+  err = _hurd_intr_rpc_mach_msg (&msg.hdr, MACH_RCV_MSG, 0,
+				 sizeof (struct msg),
+				 inf->event_port, MACH_PORT_NULL);
+
+  /* Re-suspend the task.  */
+  inf_suspend (inf);
+
+  if (err == EINTR)
+    inf_debug (inf, "interrupted");
+  else if (err)
+    error ("Couldn't wait for an event: %s", strerror (err));
+  else
+    {
+      struct {
+	mach_msg_header_t hdr;
+	mach_msg_type_t err_type;
+	kern_return_t err;
+	char noise[200];
+      } reply;
+
+      inf_debug (inf, "event: msgid = %d", msg.hdr.msgh_id);
+
+      /* Handle what we got.  */
+      if (! notify_server (&msg.hdr, &reply.hdr)
+	  && ! exc_server (&msg.hdr, &reply.hdr)
+	  && ! process_reply_server (&msg.hdr, &reply.hdr)
+	  && ! msg_reply_server (&msg.hdr, &reply.hdr))
+	/* Whatever it is, it's something strange.  */
+	error ("Got a strange event, msg id = %d.", msg.hdr.msgh_id);
+
+      if (reply.err)
+	error ("Handling event, msgid = %d: %s",
+	       msg.hdr.msgh_id, strerror (reply.err));
+    }
+
+  if (inf->pending_execs)
+    /* We're waiting for the inferior to finish execing.  */
+    {
+      struct inf_wait *w = &inf->wait;
+      enum target_waitkind kind = w->status.kind;
+
+      if (kind == TARGET_WAITKIND_SPURIOUS)
+	/* Since gdb is actually counting the number of times the inferior
+	   stops, expecting one stop per exec, we only return major events
+	   while execing.  */
+	w->suppress = 1;
+      else if (kind == TARGET_WAITKIND_STOPPED
+	       && w->status.value.sig == TARGET_SIGNAL_TRAP)
+	/* Ah hah!  A SIGTRAP from the inferior while starting up probably
+	   means we've succesfully completed an exec!  */
+	if (--inf->pending_execs == 0)
+	  /* We're done!  */
+	  {
+	    prune_threads (1);	/* Get rid of the old shell threads */
+	    renumber_threads (0); /* Give our threads reasonable names. */
+	  }
+    }
+
+  if (inf->wait.suppress)
+    /* Some totally spurious event happened that we don't consider
+       worth returning to gdb.  Just keep waiting.  */
+    {
+      inf_debug (inf, "suppressing return, rewaiting...");
+      inf_resume (inf);
+      goto rewait;
+    }
+
+  /* Pass back out our results.  */
+  bcopy (&inf->wait.status, status, sizeof (*status));
+
+  thread = inf->wait.thread;
+  if (thread)
+    tid = thread->tid;
+  else
+    thread = inf_tid_to_thread (inf, tid);
+
+  if (!thread || thread->port == MACH_PORT_NULL)
+    /* TID is dead; try and find a new thread.  */
+    if (inf_update_procs (inf) && inf->threads)
+      tid = inf->threads->tid;	/* The first available thread.  */
+    else
+      tid = -1;
+
+  if (thread && tid >= 0 && status->kind != TARGET_WAITKIND_SPURIOUS
+      && inf->pause_sc == 0 && thread->pause_sc == 0)
+    /* If something actually happened to THREAD, make sure we suspend it.  */
+    {
+      thread->sc = 1;
+      inf_update_suspends (inf);
+    }      
+
+  inf_debug (inf, "returning tid = %d, status = %s (%d)", tid,
+	     status->kind == TARGET_WAITKIND_EXITED ? "EXITED"
+	     : status->kind == TARGET_WAITKIND_STOPPED ? "STOPPED"
+	     : status->kind == TARGET_WAITKIND_SIGNALLED ? "SIGNALLED"
+	     : status->kind == TARGET_WAITKIND_LOADED ? "LOADED"
+	     : status->kind == TARGET_WAITKIND_SPURIOUS ? "SPURIOUS"
+	     : "?",
+	     status->value.integer);
+
+  return tid;
+}
+
+/* The rpc handler called by exc_server.  */
+error_t
+S_exception_raise_request (mach_port_t port, mach_port_t reply_port,
+			   thread_t thread_port, task_t task_port,
+			   int exception, int code, int subcode)
+{
+  struct inf *inf = waiting_inf;
+  struct proc *thread = inf_port_to_thread (inf, thread_port);
+
+  inf_debug (waiting_inf,
+	     "thread = %d, task = %d, exc = %d, code = %d, subcode = %d",
+	     thread_port, task_port, exception, code);
+
+  if (!thread)
+    /* We don't know about thread?  */
+    {
+      inf_update_procs (inf);
+      thread = inf_port_to_thread (inf, thread_port);
+      if (!thread)
+	/* Give up, the generating thread is gone.  */
+	return 0;
+    }
+
+  mach_port_deallocate (mach_task_self (), thread_port);
+  mach_port_deallocate (mach_task_self (), task_port);
+
+  if (! thread->aborted)
+    /* THREAD hasn't been aborted since this exception happened (abortion
+       clears any exception state), so it must be real.  */
+    {
+      /* Store away the details; this will destroy any previous info.  */
+      inf->wait.thread = thread;
+
+      inf->wait.status.kind = TARGET_WAITKIND_STOPPED;
+
+      if (exception == EXC_BREAKPOINT)
+	/* GDB likes to get SIGTRAP for breakpoints.  */
+	{
+	  inf->wait.status.value.sig = TARGET_SIGNAL_TRAP;
+	  mach_port_deallocate (mach_task_self (), reply_port);
+	}
+      else
+	/* Record the exception so that we can forward it later.  */
+	{
+	  if (thread->exc_port == port)
+	    inf->wait.exc.handler = thread->saved_exc_port;
+	  else
+	    {
+	      inf->wait.exc.handler = inf->task->saved_exc_port;
+	      assert (inf->task->exc_port == port);
+	    }
+	  if (inf->wait.exc.handler != MACH_PORT_NULL)
+	    /* Add a reference to the exception handler. */
+	    mach_port_mod_refs (mach_task_self (),
+				inf->wait.exc.handler, MACH_PORT_RIGHT_SEND,
+				1);
+
+	  inf->wait.exc.exception = exception;
+	  inf->wait.exc.code = code;
+	  inf->wait.exc.subcode = subcode;
+	  inf->wait.exc.reply = reply_port;
+
+	  /* Exceptions are encoded in the signal space by putting them after
+	     _NSIG; this assumes they're positive (and not extremely large)! */
+	  inf->wait.status.value.sig =
+	    target_signal_from_host (_NSIG + exception);
+	}
+    }
+  else
+    /* A supppressed exception, which ignore.  */
+    {
+      inf->wait.suppress = 1;
+      mach_port_deallocate (mach_task_self (), reply_port);
+    }
+
+  return 0;
+}
+
+/* Fill in INF's wait field after a task has died without giving us more
+   detailed information.  */
+void
+inf_task_died_status (struct inf *inf)
+{
+  warning ("Pid %d died with unknown exit status, using SIGKILL.", inf->pid);
+  inf->wait.status.kind = TARGET_WAITKIND_SIGNALLED;
+  inf->wait.status.value.sig = TARGET_SIGNAL_KILL;
+}
+
+/* Notify server routines.  The only real one is dead name notification.  */
+
+error_t
+do_mach_notify_dead_name (mach_port_t notify, mach_port_t dead_port)
+{
+  struct inf *inf = waiting_inf;
+
+  inf_debug (waiting_inf, "port = %d", dead_port);
+
+  if (inf->task && inf->task->port == dead_port)
+    {
+      proc_debug (inf->task, "is dead");
+      inf->task->port = MACH_PORT_NULL;
+      if (proc_wait_pid == inf->pid)
+	/* We have a wait outstanding on the process, which will return more
+	   detailed information, so delay until we get that.  */
+	inf->wait.suppress = 1;
+      else
+	/* We never waited for the process (maybe it wasn't a child), so just
+	   pretend it got a SIGKILL.  */
+	inf_task_died_status (inf);
+    }
+  else
+    {
+      struct proc *thread = inf_port_to_thread (inf, dead_port);
+      if (thread)
+	{
+	  proc_debug (thread, "is dead");
+	  thread->port = MACH_PORT_NULL;
+	}
+    }
+
+  mach_port_deallocate (mach_task_self (), dead_port);
+  inf->threads_up_to_date = 0; /* Just in case */
+
+  return 0;
+}
+
+static error_t
+ill_rpc (char *fun)
+{
+  warning ("illegal rpc: %s", fun);
+  return 0;
+}
+
+error_t
+do_mach_notify_no_senders (mach_port_t notify, mach_port_mscount_t count)
+{
+  return ill_rpc (__FUNCTION__);
+}
+
+error_t
+do_mach_notify_port_deleted (mach_port_t notify, mach_port_t name)
+{
+  return ill_rpc (__FUNCTION__);
+}
+
+error_t
+do_mach_notify_msg_accepted (mach_port_t notify, mach_port_t name)
+{
+  return ill_rpc (__FUNCTION__);
+}
+
+error_t
+do_mach_notify_port_destroyed (mach_port_t notify, mach_port_t name)
+{
+  return ill_rpc (__FUNCTION__);
+}
+
+error_t
+do_mach_notify_send_once (mach_port_t notify)
+{
+  return ill_rpc (__FUNCTION__);
+}
+
+/* Process_reply server routines.  We only use process_wait_reply.  */
+
+error_t
+S_proc_wait_reply (mach_port_t reply, error_t err,
+		 int status, rusage_t rusage, pid_t pid)
+{
+  struct inf *inf = waiting_inf;
+
+  inf_debug (inf, "err = %s, pid = %d, status = 0x%x",
+	     err ? strerror (err) : "0", pid, status);
+
+  if (err && proc_wait_pid && (!inf->task || !inf->task->port))
+    /* Ack.  The task has died, but the task-died notification code didn't
+       tell anyone because it thought a more detailed reply from the
+       procserver was forthcoming.  However, we now learn that won't
+       happen...  So we have to act like the task just died, and this time,
+       tell the world.  */
+    inf_task_died_status (inf);
+
+  if (--proc_waits_pending == 0)
+    /* PROC_WAIT_PID represents the most recent wait.  We will always get
+       replies in order because the proc server is single threaded.  */
+    proc_wait_pid = 0;
+
+  inf_debug (inf, "waits pending now: %d", proc_waits_pending);
+
+  if (err)
+    {
+      if (err != EINTR)
+	{
+	  warning ("Can't wait for pid %d: %s", inf->pid, strerror (err));
+	  inf->no_wait = 1;
+
+	  /* Since we can't see the inferior's signals, don't trap them.  */
+	  inf_set_traced (inf, 0);
+	}
+    }
+  else if (pid == inf->pid)
+    {
+      store_waitstatus (&inf->wait.status, status);
+      if (inf->wait.status.kind == TARGET_WAITKIND_STOPPED)
+	/* The process has sent us a signal, and stopped itself in a sane
+	   state pending our actions.  */
+	{
+	  inf_debug (inf, "process has stopped itself");
+	  inf->stopped = 1;
+
+	  /* We recheck the task suspend count here because the crash server
+	     messes with it in an unfriendly way, right before `stopping'.  */
+	  inf_validate_task_sc (inf);
+	}
+    }
+  else
+    inf->wait.suppress = 1;	/* Something odd happened.  Ignore.  */
+
+  return 0;
+}
+
+error_t
+S_proc_setmsgport_reply (mach_port_t reply, error_t err,
+			 mach_port_t old_msg_port)
+{
+  return ill_rpc (__FUNCTION__);
+}
+
+error_t
+S_proc_getmsgport_reply (mach_port_t reply, error_t err, mach_port_t msg_port)
+{
+  return ill_rpc (__FUNCTION__);
+}
+
+/* Msg_reply server routines.  We only use msg_sig_post_untraced_reply.  */
+
+error_t
+S_msg_sig_post_untraced_reply (mach_port_t reply, error_t err)
+{
+  struct inf *inf = waiting_inf;
+
+  if (err == EBUSY)
+    /* EBUSY is what we get when the crash server has grabbed control of the
+       process and doesn't like what signal we tried to send it.  Just act
+       like the process stopped (using a signal of 0 should mean that the
+       *next* time the user continues, it will pass signal 0, which the crash
+       server should like).  */
+    {
+      inf->wait.status.kind = TARGET_WAITKIND_STOPPED;
+      inf->wait.status.value.sig = TARGET_SIGNAL_0;
+    }
+  else if (err)
+    warning ("Signal delivery failed: %s", strerror (err));
+
+  if (err)
+    /* We only get this reply when we've posted a signal to a process which we
+       thought was stopped, and which we expected to continue after the signal.
+       Given that the signal has failed for some reason, it's reasonable to
+       assume it's still stopped.  */
+    inf->stopped = 1;
+  else
+    inf->wait.suppress = 1;
+
+  return 0;
+}
+
+error_t
+S_msg_sig_post_reply (mach_port_t reply, error_t err)
+{
+  return ill_rpc (__FUNCTION__);
+}
+
+/* Returns the number of messages queued for the receive right PORT.  */
+static mach_port_msgcount_t
+port_msgs_queued (mach_port_t port)
+{
+  struct mach_port_status status;
+  error_t err =
+    mach_port_get_receive_status (mach_task_self (), port, &status);
+
+  if (err)
+    return 0;
+  else
+    return status.mps_msgcount;
+}
+
+/* Resume execution of the inferior process.
+
+   If STEP is nonzero, single-step it.
+   If SIGNAL is nonzero, give it that signal.
+
+   TID  STEP:
+   -1   true   Single step the current thread allowing other threads to run.
+   -1   false  Continue the current thread allowing other threads to run.
+   X    true   Single step the given thread, don't allow any others to run.
+   X    false  Continue the given thread, do not allow any others to run.
+   (Where X, of course, is anything except -1)
+
+   Note that a resume may not `take' if there are pending exceptions/&c
+   still unprocessed from the last resume we did (any given resume may result
+   in multiple events returned by wait).
+*/
+static void
+gnu_resume (int tid, int step, enum target_signal sig)
+{
+  struct proc *step_thread = 0;
+  struct inf *inf = current_inferior;
+
+  inf_debug (inf, "tid = %d, step = %d, sig = %d", tid, step, sig);
+
+  if (sig != TARGET_SIGNAL_0 || inf->stopped)
+    inf_signal (inf, sig);
+  else if (inf->wait.exc.reply != MACH_PORT_NULL)
+    /* We received an exception to which we have chosen not to forward, so
+       abort the faulting thread, which will perhaps retake it.  */
+    {
+      proc_abort (inf->wait.thread, 1);
+      warning ("Aborting %s with unforwarded exception %s.",
+	       proc_string (inf->wait.thread),
+	       target_signal_to_name (inf->wait.status.value.sig));
+    }
+
+  if (port_msgs_queued (inf->event_port))
+    /* If there are still messages in our event queue, don't bother resuming
+       the process, as we're just going to stop it right away anyway. */
+    return;
+
+  if (tid < 0)
+    /* Allow all threads to run, except perhaps single-stepping one.  */
+    {
+      inf_debug (inf, "running all threads; tid = %d", inferior_pid);
+      tid = inferior_pid;	/* What to step. */
+      inf_set_threads_resume_sc (inf, 0, 1);
+    }
+  else
+    /* Just allow a single thread to run.  */
+    {
+      struct proc *thread = inf_tid_to_thread (inf, tid);
+      assert (thread);
+
+      inf_debug (inf, "running one thread: %d/%d", inf->pid, thread->tid);
+      inf_set_threads_resume_sc (inf, thread, 0);
+    }
+
+  if (step)
+    {
+      step_thread = inf_tid_to_thread (inf, tid);
+      assert (step_thread);
+      inf_debug (inf, "stepping thread: %d/%d", inf->pid, step_thread->tid);
+    }
+  if (step_thread != inf->step_thread)
+    inf_set_step_thread (inf, step_thread);
+
+  inf_debug (inf, "here we go...");
+  inf_resume (inf);
+}
+
+static void
+gnu_kill_inferior ()
+{
+  struct proc *task = current_inferior->task;
+  if (task)
+    {
+      proc_debug (task, "terminating...");
+      task_terminate (task->port);
+      task->port = MACH_PORT_NULL;
+      inf_validate_procs (current_inferior); /* Clear out the thread list &c */
+    }
+  target_mourn_inferior ();
+}
+
+/* Clean up after the inferior dies.  */
+
+static void
+gnu_mourn_inferior ()
+{
+  inf_debug (current_inferior, "rip");
+  inf_detach (current_inferior);
+  unpush_target (&gnu_ops);
+  generic_mourn_inferior ();
+}
+
+/* Fork an inferior process, and start debugging it.  */
+
+/* Set INFERIOR_PID to the first thread available in the child, if any.  */
+static void
+pick_first_thread ()
+{
+  if (current_inferior->task && current_inferior->threads)
+    /* The first thread.  */
+    inferior_pid = current_inferior->threads->tid;
+  else
+    /* What may be the next thread.  */
+    inferior_pid = next_thread_id;
+}
+
+static struct inf *
+cur_inf ()
+{
+  if (! current_inferior)
+    current_inferior = make_inf ();
+  return current_inferior;
+}
+
+static void
+gnu_create_inferior (exec_file, allargs, env)
+     char *exec_file;
+     char *allargs;
+     char **env;
+{
+  struct inf *inf = cur_inf ();
+
+  void trace_me ()
+    {
+      /* We're in the child; make this process stop as soon as it execs.  */
+      inf_debug (inf, "tracing self");
+      ptrace (PTRACE_TRACEME, 0, 0, 0);
+    }
+  void attach_to_child (int pid)
+    {
+      /* Attach to the now stopped child, which is actually a shell...  */
+      inf_debug (inf, "attaching to child: %d", pid);
+
+      inf_attach (inf, pid);
+      pick_first_thread ();
+
+      attach_flag = 0;
+      push_target (&gnu_ops);
+
+      inf->pending_execs = 2;
+      inf->traced = 1;
+
+      /* Now let the child run again, knowing that it will stop immediately
+	 because of the ptrace. */
+      inf_resume (inf);
+
+      startup_inferior (pid, inf->pending_execs);
+    }
+
+  inf_debug (inf, "creating inferior");
+
+  fork_inferior (exec_file, allargs, env, trace_me, attach_to_child, NULL);
+
+  inf_update_signal_thread (inf);
+  inf_set_traced (inf, inf->want_signals);
+
+  /* Execing the process will have trashed our exception ports; steal them
+     back (or make sure they're restored if the user wants that).  */
+  if (inf->want_exceptions)
+    inf_steal_exc_ports (inf);
+  else
+    inf_restore_exc_ports (inf);
+
+  /* Here we go!  */
+  proceed ((CORE_ADDR) -1, 0, 0);
+}
+
+/* Mark our target-struct as eligible for stray "run" and "attach"
+   commands.  */
+static int
+gnu_can_run ()
+{
+  return 1;
+}
+
+#ifdef ATTACH_DETACH
+
+/* Attach to process PID, then initialize for debugging it
+   and wait for the trace-trap that results from attaching.  */
+static void
+gnu_attach (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  int pid;
+  char *exec_file;
+  struct inf *inf = cur_inf ();
+
+  if (!args)
+    error_no_arg ("PID to attach");
+
+  pid = atoi (args);
+
+  if (pid == getpid())		/* Trying to masturbate? */
+    error ("I refuse to debug myself!");
+
+  if (from_tty)
+    {
+      exec_file = (char *) get_exec_file (0);
+
+      if (exec_file)
+	printf_unfiltered ("Attaching to program `%s', pid %d\n",
+			   exec_file, pid);
+      else
+	printf_unfiltered ("Attaching to pid %d\n", pid);
+
+      gdb_flush (gdb_stdout);
+    }
+
+  inf_debug (inf, "attaching to pid: %d", pid);
+
+  inf_attach (inf, pid);
+  inf_update_procs (inf);
+
+  pick_first_thread ();
+
+  attach_flag = 1;
+  push_target (&gnu_ops);
+
+  inf_update_signal_thread (inf);
+  inf_set_traced (inf, inf->want_signals);
+
+  /* If the process was stopped before we attached, make it continue the next
+     time the user does a continue.  */
+  inf_validate_stopped (inf);
+  inf_validate_task_sc (inf);
+}
+
+/* Take a program previously attached to and detaches it.
+   The program resumes execution and will no longer stop
+   on signals, etc.  We'd better not have left any breakpoints
+   in the program or it'll die when it hits one.  For this
+   to work, it may be necessary for the process to have been
+   previously attached.  It *might* work if the program was
+   started via fork.  */
+static void
+gnu_detach (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  if (from_tty)
+    {
+      char *exec_file = get_exec_file (0);
+      if (exec_file)
+	printf_unfiltered ("Detaching from program `%s' pid %d\n",
+			   exec_file, current_inferior->pid);
+      else
+	printf_unfiltered ("Detaching from pid %d\n", current_inferior->pid);
+      gdb_flush (gdb_stdout);
+    }
+  
+  inf_detach (current_inferior);
+
+  inferior_pid = 0;
+
+  unpush_target (&gnu_ops);		/* Pop out of handling an inferior */
+}
+#endif /* ATTACH_DETACH */
+
+static void
+gnu_terminal_init_inferior ()
+{
+  assert (current_inferior);
+  terminal_init_inferior_with_pgrp (current_inferior->pid);
+}
+
+/* Get ready to modify the registers array.  On machines which store
+   individual registers, this doesn't need to do anything.  On machines
+   which store all the registers in one fell swoop, this makes sure
+   that registers contains all the registers from the program being
+   debugged.  */
+
+static void
+gnu_prepare_to_store ()
+{
+#ifdef CHILD_PREPARE_TO_STORE
+  CHILD_PREPARE_TO_STORE ();
+#endif
+}
+
+static void
+gnu_open (arg, from_tty)
+     char *arg;
+     int from_tty;
+{
+  error ("Use the \"run\" command to start a Unix child process.");
+}
+
+static void
+gnu_stop ()
+{
+  error ("to_stop target function not implemented");
+}
+
+static int
+gnu_thread_alive (int tid)
+{
+  inf_update_procs (current_inferior);
+  return !!inf_tid_to_thread (current_inferior, tid);
+}
+
+/*
+ * Read inferior task's LEN bytes from ADDR and copy it to MYADDR
+ * in gdb's address space.
+ *
+ * Return 0 on failure; number of bytes read otherwise.
+ */
+int
+gnu_read_inferior (task, addr, myaddr, length)
+     task_t task;
+     CORE_ADDR addr;
+     char *myaddr;
+     int length;
+{
+  error_t err;
+  vm_address_t low_address = (vm_address_t) trunc_page (addr);
+  vm_size_t aligned_length =
+    (vm_size_t) round_page (addr+length) - low_address;
+  pointer_t    copied;
+  int	       copy_count;
+
+  /* Get memory from inferior with page aligned addresses */
+  err = vm_read (task, low_address, aligned_length, &copied, &copy_count);
+  if (err)
+    return 0;
+
+  err = hurd_safe_copyin (myaddr, (void*)addr - low_address + copied, length);
+  if (err)
+    {
+      warning ("Read from inferior faulted: %s", strerror (err));
+      length = 0;
+    }
+
+  err = vm_deallocate (mach_task_self (), copied, copy_count);
+  if (err)
+    warning ("gnu_read_inferior vm_deallocate failed: %s", strerror (err));
+
+  return length;
+}
+
+#define CHK_GOTO_OUT(str,ret) \
+  do if (ret != KERN_SUCCESS) { errstr = #str; goto out; } while(0)
+
+struct vm_region_list {
+  struct vm_region_list *next;
+  vm_prot_t	protection;
+  vm_address_t  start;
+  vm_size_t	length;
+};
+
+struct obstack  region_obstack;
+
+/*
+ * Write inferior task's LEN bytes from ADDR and copy it to MYADDR
+ * in gdb's address space.
+ */
+int
+gnu_write_inferior (task, addr, myaddr, length)
+     task_t task;
+     CORE_ADDR addr;
+     char *myaddr;
+     int length;
+{
+  error_t err = 0;
+  vm_address_t low_address       = (vm_address_t) trunc_page (addr);
+  vm_size_t    aligned_length = 
+    			(vm_size_t) round_page (addr+length) - low_address;
+  pointer_t    copied;
+  int	       copy_count;
+  int	       deallocate = 0;
+
+  char         *errstr = "Bug in gnu_write_inferior";
+
+  struct vm_region_list *region_element;
+  struct vm_region_list *region_head = (struct vm_region_list *)NULL;
+
+  /* Get memory from inferior with page aligned addresses */
+  err = vm_read (task,
+		 low_address,
+		 aligned_length,
+		 &copied,
+		 &copy_count);
+  CHK_GOTO_OUT ("gnu_write_inferior vm_read failed", err);
+
+  deallocate++;
+
+  err = hurd_safe_copyout ((void*)addr - low_address + copied, myaddr, length);
+  CHK_GOTO_OUT ("Write to inferior faulted", err);
+
+  obstack_init (&region_obstack);
+
+  /* Do writes atomically.
+   * First check for holes and unwritable memory.
+   */
+  {
+    vm_size_t    remaining_length  = aligned_length;
+    vm_address_t region_address    = low_address;
+
+    struct vm_region_list *scan;
+
+    while(region_address < low_address + aligned_length)
+      {
+	vm_prot_t protection;
+	vm_prot_t max_protection;
+	vm_inherit_t inheritance;
+	boolean_t shared;
+	mach_port_t object_name;
+	vm_offset_t offset;
+	vm_size_t   region_length = remaining_length;
+	vm_address_t old_address  = region_address;
+    
+	err = vm_region (task,
+			 &region_address,
+			 &region_length,
+			 &protection,
+			 &max_protection,
+			 &inheritance,
+			 &shared,
+			 &object_name,
+			 &offset);
+	CHK_GOTO_OUT ("vm_region failed", err);
+
+	/* Check for holes in memory */
+	if (old_address != region_address)
+	  {
+	    warning ("No memory at 0x%x. Nothing written",
+		     old_address);
+	    err = KERN_SUCCESS;
+	    length = 0;
+	    goto out;
+	  }
+
+	if (!(max_protection & VM_PROT_WRITE))
+	  {
+	    warning ("Memory at address 0x%x is unwritable. Nothing written",
+		     old_address);
+	    err = KERN_SUCCESS;
+	    length = 0;
+	    goto out;
+	  }
+
+	/* Chain the regions for later use */
+	region_element = 
+	  (struct vm_region_list *)
+	    obstack_alloc (&region_obstack, sizeof (struct vm_region_list));
+    
+	region_element->protection = protection;
+	region_element->start      = region_address;
+	region_element->length     = region_length;
+
+	/* Chain the regions along with protections */
+	region_element->next = region_head;
+	region_head          = region_element;
+	
+	region_address += region_length;
+	remaining_length = remaining_length - region_length;
+      }
+
+    /* If things fail after this, we give up.
+     * Somebody is messing up inferior_task's mappings.
+     */
+    
+    /* Enable writes to the chained vm regions */
+    for (scan = region_head; scan; scan = scan->next)
+      {
+	boolean_t protection_changed = FALSE;
+	
+	if (!(scan->protection & VM_PROT_WRITE))
+	  {
+	    err = vm_protect (task,
+			      scan->start,
+			      scan->length,
+			      FALSE,
+			      scan->protection | VM_PROT_WRITE);
+	    CHK_GOTO_OUT ("vm_protect: enable write failed", err);
+	  }
+      }
+
+    err = vm_write (task,
+		    low_address,
+		    copied,
+		    aligned_length);
+    CHK_GOTO_OUT ("vm_write failed", err);
+	
+    /* Set up the original region protections, if they were changed */
+    for (scan = region_head; scan; scan = scan->next)
+      {
+	boolean_t protection_changed = FALSE;
+	
+	if (!(scan->protection & VM_PROT_WRITE))
+	  {
+	    err = vm_protect (task,
+			      scan->start,
+			      scan->length,
+			      FALSE,
+			      scan->protection);
+	    CHK_GOTO_OUT ("vm_protect: enable write failed", err);
+	  }
+      }
+  }
+
+ out:
+  if (deallocate)
+    {
+      obstack_free (&region_obstack, 0);
+      
+      (void) vm_deallocate (mach_task_self (),
+			    copied,
+			    copy_count);
+    }
+
+  if (err != KERN_SUCCESS)
+    {
+      warning ("%s: %s", errstr, mach_error_string (err));
+      return 0;
+    }
+
+  return length;
+}
+
+/* Return 0 on failure, number of bytes handled otherwise.  */
+static int
+gnu_xfer_memory (memaddr, myaddr, len, write, target)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+     int write;
+     struct target_ops *target;	/* IGNORED */
+{
+  int result;
+  task_t task =
+    current_inferior
+      ? (current_inferior->task ? current_inferior->task->port : 0)
+      : 0;
+
+  if (task == MACH_PORT_NULL)
+    return 0;
+  else
+    {
+      inf_debug (current_inferior, "%s %p[%d] %s %p",
+		 write ? "writing" : "reading", memaddr, len,
+		 write ? "<--" : "-->", myaddr);
+      if (write)
+	return gnu_write_inferior (task, memaddr, myaddr, len);
+      else
+	return gnu_read_inferior  (task, memaddr, myaddr, len);
+    }
+}
+
+extern void gnu_store_registers (int regno);
+extern void gnu_fetch_registers (int regno);
+
+struct target_ops gnu_ops = {
+  "GNU",			/* to_shortname */
+  "GNU Hurd process",		/* to_longname */
+  "GNU Hurd process",		/* to_doc */
+  gnu_open,			/* to_open */
+  0,				/* to_close */
+  gnu_attach,			/* to_attach */
+  gnu_detach,	 		/* to_detach */
+  gnu_resume,			/* to_resume */
+  gnu_wait,			/* to_wait */
+  gnu_fetch_registers,		/* to_fetch_registers */
+  gnu_store_registers,		/* to_store_registers */
+  gnu_prepare_to_store,		/* to_prepare_to_store */
+  gnu_xfer_memory,		/* to_xfer_memory */
+  0,				/* to_files_info */
+  memory_insert_breakpoint,	/* to_insert_breakpoint */
+  memory_remove_breakpoint,	/* to_remove_breakpoint */
+  gnu_terminal_init_inferior,	/* to_terminal_init */
+  terminal_inferior, 		/* to_terminal_inferior */
+  terminal_ours_for_output,	/* to_terminal_ours_for_output */
+  terminal_ours,		/* to_terminal_ours */
+  child_terminal_info,		/* to_terminal_info */
+  gnu_kill_inferior,		/* to_kill */
+  0,				/* to_load */
+  0,				/* to_lookup_symbol */
+
+  gnu_create_inferior,		/* to_create_inferior */
+  gnu_mourn_inferior,		/* to_mourn_inferior */
+  gnu_can_run,			/* to_can_run */
+  0,				/* to_notice_signals */
+  gnu_thread_alive,		/* to_thread_alive */
+  gnu_stop,			/* to_stop */
+  process_stratum,		/* to_stratum */
+  0,				/* to_next */
+  1,				/* to_has_all_memory */
+  1,				/* to_has_memory */
+  1,				/* to_has_stack */
+  1,				/* to_has_registers */
+  1,				/* to_has_execution */
+  0,				/* sections */
+  0,				/* sections_end */
+  OPS_MAGIC			/* to_magic */
+};
+
+char *proc_string (struct proc *proc)
+{
+  static char tid_str[80];
+  if (proc_is_task (proc))
+    sprintf (tid_str, "process %d", proc->inf->pid);
+  else
+    sprintf (tid_str, "thread %d.%d",
+	     proc->inf->pid,
+	     pid_to_thread_id (proc->tid));
+  return tid_str;
+}
+
+char *
+gnu_target_pid_to_str (int tid)
+{
+  struct inf *inf = current_inferior;
+  struct proc *thread = inf_tid_to_thread (inf, tid);
+
+  if (thread)
+    return proc_string (thread);
+  else
+    {
+      static char tid_str[80];
+      sprintf (tid_str, "bogus thread id %d", tid);
+      return tid_str;
+    }
+}
+
+/* User task commands.  */
+
+struct cmd_list_element *set_task_cmd_list = 0;
+struct cmd_list_element *show_task_cmd_list = 0;
+
+extern struct cmd_list_element *set_thread_default_cmd_list;
+extern struct cmd_list_element *show_thread_default_cmd_list;
+
+static int
+_parse_bool_arg (char *args, char *t_val, char *f_val, char *cmd_prefix)
+{
+  if (!args || strcmp (args, t_val) == 0)
+    return 1;
+  else if (strcmp (args, f_val) == 0)
+    return 0;
+  else
+    error ("Illegal argument for \"%s\" command, should be \"%s\" or \"%s\".",
+	   cmd_prefix, t_val, f_val);
+}
+
+#define parse_bool_arg(args, cmd_prefix) \
+  _parse_bool_arg (args, "on", "off", cmd_prefix)
+
+static void
+check_empty (char *args, char *cmd_prefix)
+{
+  if (args)
+    error ("Garbage after \"%s\" command: `%s'", cmd_prefix, args);
+}
+
+/* Returns the alive thread named by INFERIOR_PID, or signals an error.  */
+static struct proc *
+cur_thread ()
+{
+  struct inf *inf = cur_inf ();
+  struct proc *thread = inf_tid_to_thread (inf, inferior_pid);
+  if (!thread)
+    error ("No current thread.");
+  return thread;
+}
+
+static void
+set_task_pause_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  int old_sc = inf->pause_sc;
+
+  inf->pause_sc = parse_bool_arg (args, "set task pause");
+
+  if (old_sc == 0 && inf->pause_sc != 0)
+    /* If the task is currently unsuspended, immediately suspend it,
+       otherwise wait until the next time it gets control.  */
+    inf_suspend (inf);
+}
+
+static void
+show_task_pause_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  check_empty (args, "show task pause");
+  printf_unfiltered ("The inferior task %s suspended while gdb has control.\n",
+		     inf->task
+		     ? (inf->pause_sc == 0 ? "isn't" : "is")
+		     : (inf->pause_sc == 0 ? "won't be" : "will be"));
+}
+
+static void
+set_thread_default_pause_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  inf->default_thread_pause_sc =
+    parse_bool_arg (args, "set thread default pause") ? 0 : 1;
+}
+
+static void
+show_thread_default_pause_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  int sc = inf->default_thread_pause_sc;
+  check_empty (args, "show thread default pause");
+  printf_unfiltered ("New threads %s suspended while gdb has control%s.\n",
+		     sc ? "are" : "aren't",
+		     !sc && inf->pause_sc ? "(but the task is)" : "");
+}
+
+static void
+set_thread_default_run_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  inf->default_thread_run_sc =
+    parse_bool_arg (args, "set thread default run") ? 0 : 1;
+}
+
+static void
+show_thread_default_run_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  check_empty (args, "show thread default run");
+  printf_unfiltered ("New threads %s allowed to run.\n",
+		     inf->default_thread_run_sc == 0 ? "are" : "aren't");
+}
+
+/* Steal a send right called NAME in the inferior task, and make it PROC's
+   saved exception port.  */
+static void
+steal_exc_port (struct proc *proc, mach_port_t name)
+{
+  error_t err;
+  mach_port_t port;
+  mach_msg_type_name_t port_type;
+
+  if (!proc || !proc->inf->task)
+    error ("No inferior task.");
+
+  err = mach_port_extract_right (proc->inf->task->port,
+				 name, MACH_MSG_TYPE_COPY_SEND,
+				 &port, &port_type);
+  if (err)
+    error ("Couldn't extract send right %d from inferior: %s",
+	   name, strerror (err));
+
+  if (proc->saved_exc_port)
+    /* Get rid of our reference to the old one.  */
+    mach_port_deallocate (mach_task_self (), proc->saved_exc_port);
+
+  proc->saved_exc_port = port;
+
+  if (! proc->exc_port)
+    /* If PROC is a thread, we may not have set its exception port before.
+       We can't use proc_steal_exc_port because it also sets saved_exc_port. */
+    {
+       proc->exc_port = proc->inf->event_port;
+       err = proc_set_exception_port (proc, proc->exc_port);
+       error ("Can't set exception port for %s: %s",
+	      proc_string (proc), strerror (err));
+    }
+}
+
+static void
+set_task_exc_port_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  if (!args)
+    error ("No argument to \"set task exception-port\" command.");
+  steal_exc_port (inf->task, parse_and_eval_address (args));
+}
+
+static void 
+set_signals_cmd (char *args, int from_tty)
+{
+  int trace;
+  struct inf *inf = cur_inf ();
+
+  inf->want_signals = parse_bool_arg (args, "set signals");
+
+  if (inf->task && inf->want_signals != inf->traced)
+    /* Make this take effect immediately in a running process.  */
+    inf_set_traced (inf, inf->want_signals);
+}
+
+static void
+show_signals_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  check_empty (args, "show signals");
+  printf_unfiltered ("The inferior process's signals %s intercepted.\n",
+		     inf->task
+		     ? (inf->traced ? "are" : "aren't")
+		     : (inf->want_signals ? "will be" : "won't be"));
+}
+
+static void 
+set_stopped_cmd (char *args, int from_tty)
+{
+  cur_inf ()->stopped = _parse_bool_arg (args, "yes", "no", "set stopped");
+}
+
+static void
+show_stopped_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  check_empty (args, "show stopped");
+  if (! inf->task)
+    error ("No current process.");
+  printf_unfiltered ("The inferior process %s stopped.\n",
+		     inf->stopped ? "is" : "isn't");
+}
+
+static void 
+set_sig_thread_cmd (char *args, int from_tty)
+{
+  int tid;
+  struct inf *inf = cur_inf ();
+
+  if (!args || (! isdigit (*args) && strcmp (args, "none") != 0))
+    error ("Illegal argument to \"set signal-thread\" command.\n"
+	   "Should be an integer thread ID, or `none'.");
+
+  if (strcmp (args, "none") == 0)
+    inf->signal_thread = 0;
+  else
+    {
+      int tid = thread_id_to_pid (atoi (args));
+      if (tid < 0)
+	error ("Thread ID %s not known.  Use the \"info threads\" command to\n"
+	       "see the IDs of currently known threads.", args);
+      inf->signal_thread = inf_tid_to_thread (inf, tid);
+    }
+}
+
+static void
+show_sig_thread_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  check_empty (args, "show signal-thread");
+  if (! inf->task)
+    error ("No current process.");
+  if (inf->signal_thread)
+    printf_unfiltered ("The signal thread is %s.\n",
+		       proc_string (inf->signal_thread));
+  else
+    printf_unfiltered ("There is no signal thread.\n");
+}
+
+static void 
+set_exceptions_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  int val = parse_bool_arg (args, "set exceptions");
+
+  if (inf->task && inf->want_exceptions != val)
+    /* Make this take effect immediately in a running process.  */
+    /* XXX */;
+
+  inf->want_exceptions = val;
+}
+
+static void
+show_exceptions_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+  check_empty (args, "show exceptions");
+  printf_unfiltered ("Exceptions in the inferior %s trapped.\n",
+		     inf->task
+		     ? (inf->want_exceptions ? "are" : "aren't")
+		     : (inf->want_exceptions ? "will be" : "won't be"));
+}
+
+static void
+set_task_cmd (char *args, int from_tty)
+{
+  printf_unfiltered ("\"set task\" must be followed by the name of a task property.\n");
+}
+
+static void
+show_task_cmd (char *args, int from_tty)
+{
+  struct inf *inf = cur_inf ();
+
+  check_empty (args, "show task");
+
+  show_signals_cmd (0, from_tty);
+  show_exceptions_cmd (0, from_tty);
+  show_task_pause_cmd (0, from_tty);
+
+  if (inf->pause_sc == 0)
+    show_thread_default_pause_cmd (0, from_tty);
+  show_thread_default_run_cmd (0, from_tty);
+
+  if (inf->task)
+    {
+      show_stopped_cmd (0, from_tty);
+      show_sig_thread_cmd (0, from_tty);
+    }
+}
+
+static void add_task_commands ()
+{
+  add_cmd ("pause", class_run, set_thread_default_pause_cmd,
+	   "Set whether the new threads are suspended while gdb has control.\n"
+	   "This property normally has no effect because the whole task is\n"
+	   "suspended, however, that may be disabled with \"set task pause off\".\n"
+	   "The default value is \"off\".",
+	   &set_thread_default_cmd_list);
+  add_cmd ("pause", no_class, show_thread_default_pause_cmd,
+	   "Show whether new threads are suspended while gdb has control.",
+	   &show_thread_default_cmd_list);
+  add_cmd ("run", class_run, set_thread_default_run_cmd,
+	   "Set whether new threads are allowed to run (once gdb has noticed them).",
+	   &set_thread_default_cmd_list);
+  add_cmd ("run", no_class, show_thread_default_run_cmd,
+	   "Show whether new threads are allowed to run (once gdb has noticed
+them).",
+	   &show_thread_default_cmd_list);
+
+  add_cmd ("signals", class_run, set_signals_cmd,
+	   "Set whether the inferior process's signals will be intercepted.\n"
+	   "Mach exceptions (such as breakpoint traps) are not affected.",
+	   &setlist);
+  add_alias_cmd ("sigs", "signals", class_run, 1, &setlist);
+  add_cmd ("signals", no_class, show_signals_cmd,
+	   "Show whether the inferior process's signals will be intercepted.",
+	   &showlist);
+  add_alias_cmd ("sigs", "signals", no_class, 1, &showlist);
+
+  add_cmd ("signal-thread", class_run, set_sig_thread_cmd,
+	   "Set the thread that gdb thinks is the libc signal thread.\n"
+	   "This thread is run when delivering a signal to a non-stopped process.",
+	   &setlist);
+  add_alias_cmd ("sigthread", "signal-thread", class_run, 1, &setlist);
+  add_cmd ("signal-thread", no_class, show_sig_thread_cmd,
+	   "Set the thread that gdb thinks is the libc signal thread.",
+	   &showlist);
+  add_alias_cmd ("sigthread", "signal-thread", no_class, 1, &showlist);
+
+  add_cmd ("stopped", class_run, set_stopped_cmd,
+	   "Set whether gdb thinks the inferior process is stopped as with SIGSTOP.\n"
+	   "Stopped process will be continued by sending them a signal.",
+	   &setlist);
+  add_cmd ("stopped", no_class, show_signals_cmd,
+	   "Show whether gdb thinks the inferior process is stopped as with SIGSTOP.",
+	   &showlist);
+
+  add_cmd ("exceptions", class_run, set_exceptions_cmd,
+	   "Set whether exceptions in the inferior process will be trapped.\n"
+	   "When exceptions are turned off, neither breakpoints nor single-stepping\n"
+	   "will work.",
+	   &setlist);
+  /* Allow `set exc' despite conflict with `set exception-port'.  */
+  add_alias_cmd ("exc", "exceptions", class_run, 1, &setlist);
+  add_cmd ("exceptions", no_class, show_exceptions_cmd,
+	   "Show whether exceptions in the inferior process will be trapped.",
+	   &showlist);
+
+  
+
+  add_prefix_cmd ("task", no_class, set_task_cmd,
+		  "Command prefix for setting task attributes.",
+		  &set_task_cmd_list, "set task ", 0, &setlist);
+  add_prefix_cmd ("task", no_class, show_task_cmd,
+		  "Command prefix for showing task attributes.",
+		  &show_task_cmd_list, "show task ", 0, &showlist);
+
+  add_cmd ("pause", class_run, set_task_pause_cmd,
+	   "Set whether the task is suspended while gdb has control.\n"
+	   "A value of \"on\" takes effect immediately, otherwise nothing\n"
+	   "happens until the next time the program is continued.\n"
+	   "When setting this to \"off\", \"set thread default pause on\"\n"
+	   "can be used to pause individual threads by default instead.",
+	   &set_task_cmd_list);
+  add_cmd ("pause", no_class, show_task_pause_cmd,
+	   "Show whether the task is suspended while gdb has control.",
+	   &show_task_cmd_list);
+
+  add_cmd ("exception-port", no_class, set_task_exc_port_cmd,
+	   "Set the task exception port to which we forward exceptions.\n"
+	   "The argument should be the value of the send right in the task.",
+	   &set_task_cmd_list);
+  add_alias_cmd ("excp", "exception-port", no_class, 1, &set_task_cmd_list);
+  add_alias_cmd ("exc-port", "exception-port", no_class, 1, &set_task_cmd_list);
+}
+
+/* User thread commands.  */
+
+extern struct cmd_list_element *set_thread_cmd_list;
+extern struct cmd_list_element *show_thread_cmd_list;
+
+static void
+set_thread_pause_cmd (char *args, int from_tty)
+{
+  struct proc *thread = cur_thread ();
+  int old_sc = thread->pause_sc;
+  thread->pause_sc = parse_bool_arg (args, "set thread pause");
+  if (old_sc == 0 && thread->pause_sc != 0 && thread->inf->pause_sc == 0)
+    /* If the task is currently unsuspended, immediately suspend it,
+       otherwise wait until the next time it gets control.  */
+    inf_suspend (thread->inf);
+}
+
+static void
+show_thread_pause_cmd (char *args, int from_tty)
+{
+  struct proc *thread = cur_thread ();
+  int sc = thread->pause_sc;
+  check_empty (args, "show task pause");
+  printf_unfiltered ("Thread %s %s suspended while gdb has control%s.\n",
+		     proc_string (thread),
+		     sc ? "is" : "isn't",
+		     !sc && thread->inf->pause_sc ? "(but the task is)" : "");
+}
+
+static void
+set_thread_run_cmd (char *args, int from_tty)
+{
+  struct proc *thread = cur_thread ();
+  thread->run_sc = parse_bool_arg (args, "set thread run") ? 0 : 1;
+}
+
+static void
+show_thread_run_cmd (char *args, int from_tty)
+{
+  struct proc *thread = cur_thread ();
+  check_empty (args, "show thread run");
+  printf_unfiltered ("Thread %s allowed to run.",
+		     proc_string (thread),
+		     thread->run_sc == 0 ? "is" : "isn't");
+}
+
+static void
+set_thread_exc_port_cmd (char *args, int from_tty)
+{
+  struct proc *thread = cur_thread ();
+  if (!args)
+    error ("No argument to \"set thread exception-port\" command.");
+  steal_exc_port (thread, parse_and_eval_address (args));
+}
+
+static void 
+set_thread_cmd (char *args, int from_tty)
+{
+  printf_unfiltered ("\"set thread\" must be followed by the name of a thread property.\n");
+}
+
+static void
+show_thread_cmd (char *args, int from_tty)
+{
+  check_empty (args, "show thread");
+  show_thread_run_cmd (0, from_tty);
+  show_thread_pause_cmd (0, from_tty);
+}
+
+add_thread_commands ()
+{
+  add_cmd ("pause", class_run, set_thread_pause_cmd,
+	   "Set whether the current thread is suspended while gdb has control.\n"
+	   "A value of \"on\" takes effect immediately, otherwise nothing\n"
+	   "happens until the next time the program is continued.  This\n"
+	   "property normally has no effect because the whole task is suspended,\n"
+	   "however, that may be disabled with \"set task pause off\".\n"
+	   "The default value is \"off\".",
+	   &set_thread_cmd_list);
+  add_cmd ("pause", no_class, show_thread_pause_cmd,
+	   "Show whether the current thread is suspended while gdb has control.",
+	   &show_thread_cmd_list);
+
+  add_cmd ("run", class_run, set_thread_run_cmd,
+	   "Set whether the current thread is allowed to run.",
+	   &set_thread_cmd_list);
+  add_cmd ("run", no_class, show_thread_run_cmd,
+	   "Show whether the current thread is allowed to run.",
+	   &show_thread_cmd_list);
+
+  add_cmd ("exception-port", no_class, set_thread_exc_port_cmd,
+	   "Set the exception port to which we forward exceptions for the\n"
+	   "current thread, overriding the task exception port.\n"
+	   "The argument should be the value of the send right in the task.",
+	   &set_thread_cmd_list);
+  add_alias_cmd ("excp", "exception-port", no_class, 1, &set_thread_cmd_list);
+  add_alias_cmd ("exc-port", "exception-port", no_class, 1, &set_thread_cmd_list);
+}
+
+void
+_initialize_gnu_nat ()
+{
+  proc_server = getproc ();
+
+  add_target (&gnu_ops);
+
+  add_task_commands ();
+  add_thread_commands ();
+
+#if MAINTENANCE_CMDS
+  add_set_cmd ("gnu-debug", class_maintenance,
+	       var_boolean, (char *)&gnu_debug_flag,
+	       "Set debugging output for the gnu backend.", &maintenancelist);
+#endif
+}
+
+#ifdef	FLUSH_INFERIOR_CACHE
+
+/* When over-writing code on some machines the I-Cache must be flushed
+   explicitly, because it is not kept coherent by the lazy hardware.
+   This definitely includes breakpoints, for instance, or else we
+   end up looping in mysterious Bpt traps */
+
+void
+flush_inferior_icache(pc, amount)
+     CORE_ADDR pc;
+{
+  vm_machine_attribute_val_t flush = MATTR_VAL_ICACHE_FLUSH;
+  error_t   ret;
+  
+  ret = vm_machine_attribute (current_inferior->task->port,
+			      pc,
+			      amount,
+			      MATTR_CACHE,
+			      &flush);
+  if (ret != KERN_SUCCESS)
+    warning ("Error flushing inferior's cache : %s", strerror (ret));
+}
+#endif	FLUSH_INFERIOR_CACHE