/* Copyright (C) 1991-2018 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 Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <cthreads.h>		/* For `struct mutex'.  */

#include <pthreadP.h>

#include <mach.h>

#include <mach/thread_switch.h>

#include <mach/mig_support.h>

#include <hurd.h>

#include <hurd/id.h>

#include <hurd/signal.h>

#include "hurdfault.h"

#include "hurdmalloc.h"		/* XXX */

#include "../locale/localeinfo.h"

#include <libc-diag.h>

const char *_hurdsig_getenv (const char *);

struct mutex _hurd_siglock;

int _hurd_stopped;

/* Port that receives signals and other miscellaneous messages.  */

mach_port_t _hurd_msgport;

/* Thread listening on it.  */

thread_t _hurd_msgport_thread;

/* Thread which receives task-global signals.  */

thread_t _hurd_sigthread;

/* These are set up by _hurdsig_init.  */

unsigned long int __hurd_sigthread_stack_base;

unsigned long int __hurd_sigthread_stack_end;

/* Linked-list of per-thread signal state.  */

struct hurd_sigstate *_hurd_sigstates;

/* Timeout for RPC's after interrupt_operation. */

mach_msg_timeout_t _hurd_interrupted_rpc_timeout = 3000;

static void

default_sigaction (struct sigaction actions[NSIG])

{

  int signo;

  __sigemptyset (&actions[0].sa_mask);

  actions[0].sa_flags = SA_RESTART;

  actions[0].sa_handler = SIG_DFL;

  for (signo = 1; signo < NSIG; ++signo)

    actions[signo] = actions[0];

}

struct hurd_sigstate *

_hurd_thread_sigstate (thread_t thread)

{

  struct hurd_sigstate *ss;

  __mutex_lock (&_hurd_siglock);

  for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)

    if (ss->thread == thread)

       break;

  if (ss == NULL)

    {

      ss = malloc (sizeof (*ss));

      if (ss == NULL)

	__libc_fatal ("hurd: Can't allocate thread sigstate\n");

      ss->thread = thread;

      __spin_lock_init (&ss->lock);

      /* Initialize default state.  */

      __sigemptyset (&ss->blocked);

      __sigemptyset (&ss->pending);

      memset (&ss->sigaltstack, 0, sizeof (ss->sigaltstack));

      ss->preemptors = NULL;

      ss->suspended = MACH_PORT_NULL;

      ss->intr_port = MACH_PORT_NULL;

      ss->context = NULL;

      /* Initialize the sigaction vector from the default signal receiving

	 thread's state, and its from the system defaults.  */

      if (thread == _hurd_sigthread)

	default_sigaction (ss->actions);

      else

	{

	  struct hurd_sigstate *s;

	  for (s = _hurd_sigstates; s != NULL; s = s->next)

	    if (s->thread == _hurd_sigthread)

	      break;

	  if (s)

	    {

	      __spin_lock (&s->lock);

	      memcpy (ss->actions, s->actions, sizeof (s->actions));

	      __spin_unlock (&s->lock);

	    }

	  else

	    default_sigaction (ss->actions);

	}

      ss->next = _hurd_sigstates;

      _hurd_sigstates = ss;

    }

  __mutex_unlock (&_hurd_siglock);

  return ss;

}

libc_hidden_def (_hurd_thread_sigstate)

/* Signal delivery itself is on this page.  */

#include <hurd/fd.h>

#include <hurd/crash.h>

#include <hurd/resource.h>

#include <hurd/paths.h>

#include <setjmp.h>

#include <fcntl.h>

#include <sys/wait.h>

#include <thread_state.h>

#include <hurd/msg_server.h>

#include <hurd/msg_reply.h>	/* For __msg_sig_post_reply.  */

#include <hurd/interrupt.h>

#include <assert.h>

#include <unistd.h>

/* Call the crash dump server to mummify us before we die.

   Returns nonzero if a core file was written.  */

static int

write_corefile (int signo, const struct hurd_signal_detail *detail)

{

  error_t err;

  mach_port_t coreserver;

  file_t file, coredir;

  const char *name;

  /* Don't bother locking since we just read the one word.  */

  rlim_t corelimit = _hurd_rlimits[RLIMIT_CORE].rlim_cur;

  if (corelimit == 0)

    /* No core dumping, thank you very much.  Note that this makes

       `ulimit -c 0' prevent crash-suspension too, which is probably

       what the user wanted.  */

    return 0;

  /* XXX RLIMIT_CORE:

     When we have a protocol to make the server return an error

     for RLIMIT_FSIZE, then tell the corefile fs server the RLIMIT_CORE

     value in place of the RLIMIT_FSIZE value.  */

  /* First get a port to the core dumping server.  */

  coreserver = MACH_PORT_NULL;

  name = _hurdsig_getenv ("CRASHSERVER");

  if (name != NULL)

    coreserver = __file_name_lookup (name, 0, 0);

  if (coreserver == MACH_PORT_NULL)

    coreserver = __file_name_lookup (_SERVERS_CRASH, 0, 0);

  if (coreserver == MACH_PORT_NULL)

    return 0;

  /* Get a port to the directory where the new core file will reside.  */

  file = MACH_PORT_NULL;

  name = _hurdsig_getenv ("COREFILE");

  if (name == NULL)

    name = "core";

  coredir = __file_name_split (name, (char **) &name);

  if (coredir != MACH_PORT_NULL)

    /* Create the new file, but don't link it into the directory yet.  */

    __dir_mkfile (coredir, O_WRONLY|O_CREAT,

		  0600 & ~_hurd_umask, /* XXX ? */

		  &file;;

  /* Call the core dumping server to write the core file.  */

  err = __crash_dump_task (coreserver,

			   __mach_task_self (),

			   file,

			   signo, detail->code, detail->error,

			   detail->exc, detail->exc_code, detail->exc_subcode,

			   _hurd_ports[INIT_PORT_CTTYID].port,

			   MACH_MSG_TYPE_COPY_SEND);

  __mach_port_deallocate (__mach_task_self (), coreserver);

  if (! err && file != MACH_PORT_NULL)

    /* The core dump into FILE succeeded, so now link it into the

       directory.  */

    err = __dir_link (coredir, file, name, 1);

  __mach_port_deallocate (__mach_task_self (), file);

  __mach_port_deallocate (__mach_task_self (), coredir);

  return !err && file != MACH_PORT_NULL;

}

/* The lowest-numbered thread state flavor value is 1,

   so we use bit 0 in machine_thread_all_state.set to

   record whether we have done thread_abort.  */

#define THREAD_ABORTED 1

/* SS->thread is suspended.  Abort the thread and get its basic state.  */

static void

abort_thread (struct hurd_sigstate *ss, struct machine_thread_all_state *state,

	      void (*reply) (void))

{

  if (!(state->set & THREAD_ABORTED))

    {

      error_t err = __thread_abort (ss->thread);

      assert_perror (err);

      /* Clear all thread state flavor set bits, because thread_abort may

	 have changed the state.  */

      state->set = THREAD_ABORTED;

    }

  if (reply)

    (*reply) ();

  machine_get_basic_state (ss->thread, state);

}

/* Find the location of the MiG reply port cell in use by the thread whose

   state is described by THREAD_STATE.  If SIGTHREAD is nonzero, make sure

   that this location can be set without faulting, or else return NULL.  */

static mach_port_t *

interrupted_reply_port_location (thread_t thread,

				 struct machine_thread_all_state *thread_state,

				 int sigthread)

{

  mach_port_t *portloc = &THREAD_TCB(thread, thread_state)->reply_port;

  if (sigthread && _hurdsig_catch_memory_fault (portloc))

    /* Faulted trying to read the TCB.  */

    return NULL;

  DIAG_PUSH_NEEDS_COMMENT;

  /* GCC 6 and before seem to be confused by the setjmp call inside

     _hurdsig_catch_memory_fault and think that we may be returning a second

     time to here with portloc uninitialized (but we never do). */

  DIAG_IGNORE_NEEDS_COMMENT (6, "-Wmaybe-uninitialized");

  /* Fault now if this pointer is bogus.  */

  *(volatile mach_port_t *) portloc = *portloc;

  DIAG_POP_NEEDS_COMMENT;

  if (sigthread)

    _hurdsig_end_catch_fault ();

  return portloc;

}

#include <hurd/sigpreempt.h>

#include <intr-msg.h>

/* Timeout on interrupt_operation calls.  */

mach_msg_timeout_t _hurdsig_interrupt_timeout = 1000;

/* SS->thread is suspended.

   Abort any interruptible RPC operation the thread is doing.

   This uses only the constant member SS->thread and the unlocked, atomically

   set member SS->intr_port, so no locking is needed.

   If successfully sent an interrupt_operation and therefore the thread should

   wait for its pending RPC to return (possibly EINTR) before taking the

   incoming signal, returns the reply port to be received on.  Otherwise

   returns MACH_PORT_NULL.

   SIGNO is used to find the applicable SA_RESTART bit.  If SIGNO is zero,

   the RPC fails with EINTR instead of restarting (thread_cancel).

   *STATE_CHANGE is set nonzero if STATE->basic was modified and should

   be applied back to the thread if it might ever run again, else zero.  */

mach_port_t

_hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread,

		     struct machine_thread_all_state *state, int *state_change,

		     void (*reply) (void))

{

  extern const void _hurd_intr_rpc_msg_in_trap;

  mach_port_t rcv_port = MACH_PORT_NULL;

  mach_port_t intr_port;

  *state_change = 0;

  intr_port = ss->intr_port;

  if (intr_port == MACH_PORT_NULL)

    /* No interruption needs done.  */

    return MACH_PORT_NULL;

  /* Abort the thread's kernel context, so any pending message send or

     receive completes immediately or aborts.  */

  abort_thread (ss, state, reply);

  if (state->basic.PC < (natural_t) &_hurd_intr_rpc_msg_in_trap)

    {

      /* The thread is about to do the RPC, but hasn't yet entered

	 mach_msg.  Mutate the thread's state so it knows not to try

	 the RPC.  */

      INTR_MSG_BACK_OUT (&state->basic);

      MACHINE_THREAD_STATE_SET_PC (&state->basic,

				   &_hurd_intr_rpc_msg_in_trap);

      state->basic.SYSRETURN = MACH_SEND_INTERRUPTED;

      *state_change = 1;

    }

  else if (state->basic.PC == (natural_t) &_hurd_intr_rpc_msg_in_trap &&

	   /* The thread was blocked in the system call.  After thread_abort,

	      the return value register indicates what state the RPC was in

	      when interrupted.  */

	   state->basic.SYSRETURN == MACH_RCV_INTERRUPTED)

      {

	/* The RPC request message was sent and the thread was waiting for

	   the reply message; now the message receive has been aborted, so

	   the mach_msg call will return MACH_RCV_INTERRUPTED.  We must tell

	   the server to interrupt the pending operation.  The thread must

	   wait for the reply message before running the signal handler (to

	   guarantee that the operation has finished being interrupted), so

	   our nonzero return tells the trampoline code to finish the message

	   receive operation before running the handler.  */

	mach_port_t *reply = interrupted_reply_port_location (ss->thread,

							      state,

							      sigthread);

	error_t err = __interrupt_operation (intr_port, _hurdsig_interrupt_timeout);

	if (err)

	  {

	    if (reply)

	      {

		/* The interrupt didn't work.

		   Destroy the receive right the thread is blocked on.  */

		__mach_port_destroy (__mach_task_self (), *reply);

		*reply = MACH_PORT_NULL;

	      }

	    /* The system call return value register now contains

	       MACH_RCV_INTERRUPTED; when mach_msg resumes, it will retry the

	       call.  Since we have just destroyed the receive right, the

	       retry will fail with MACH_RCV_INVALID_NAME.  Instead, just

	       change the return value here to EINTR so mach_msg will not

	       retry and the EINTR error code will propagate up.  */

	    state->basic.SYSRETURN = EINTR;

	    *state_change = 1;

	  }

	else if (reply)

	  rcv_port = *reply;

	/* All threads whose RPCs were interrupted by the interrupt_operation

	   call above will retry their RPCs unless we clear SS->intr_port.

	   So we clear it for the thread taking a signal when SA_RESTART is

	   clear, so that its call returns EINTR.  */

	if (! signo || !(ss->actions[signo].sa_flags & SA_RESTART))

	  ss->intr_port = MACH_PORT_NULL;

      }

  return rcv_port;

}

/* Abort the RPCs being run by all threads but this one;

   all other threads should be suspended.  If LIVE is nonzero, those

   threads may run again, so they should be adjusted as necessary to be

   happy when resumed.  STATE is clobbered as a scratch area; its initial

   contents are ignored, and its contents on return are not useful.  */

static void

abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live)

{

  /* We can just loop over the sigstates.  Any thread doing something

     interruptible must have one.  We needn't bother locking because all

     other threads are stopped.  */

  struct hurd_sigstate *ss;

  size_t nthreads;

  mach_port_t *reply_ports;

  /* First loop over the sigstates to count them.

     We need to know how big a vector we will need for REPLY_PORTS.  */

  nthreads = 0;

  for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)

    ++nthreads;

  reply_ports = alloca (nthreads * sizeof *reply_ports);

  nthreads = 0;

  for (ss = _hurd_sigstates; ss != NULL; ss = ss->next, ++nthreads)

    if (ss->thread == _hurd_msgport_thread)

      reply_ports[nthreads] = MACH_PORT_NULL;

    else

      {

	int state_changed;

	state->set = 0;		/* Reset scratch area.  */

	/* 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 (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.  */

  while (nthreads-- > 0)

    if (reply_ports[nthreads] != MACH_PORT_NULL)

      {

	error_t err;

	mach_msg_header_t head;

	err = __mach_msg (&head, MACH_RCV_MSG|MACH_RCV_TIMEOUT, 0, sizeof head,

			  reply_ports[nthreads],

			  _hurd_interrupted_rpc_timeout, MACH_PORT_NULL);

	switch (err)

	  {

	  case MACH_RCV_TIMED_OUT:

	  case MACH_RCV_TOO_LARGE:

	    break;

	  default:

	    assert_perror (err);

	  }

      }

}

struct hurd_signal_preemptor *_hurdsig_preemptors = 0;

sigset_t _hurdsig_preempted_set;

/* XXX temporary to deal with spelling fix */

weak_alias (_hurdsig_preemptors, _hurdsig_preempters)

/* Mask of stop signals.  */

#define STOPSIGS (sigmask (SIGTTIN) | sigmask (SIGTTOU) | \

		  sigmask (SIGSTOP) | sigmask (SIGTSTP))

/* Deliver a signal.  SS is not locked.  */

void

_hurd_internal_post_signal (struct hurd_sigstate *ss,

			    int signo, struct hurd_signal_detail *detail,

			    mach_port_t reply_port,

			    mach_msg_type_name_t reply_port_type,

			    int untraced)

{

  error_t err;

  struct machine_thread_all_state thread_state;

  enum { stop, ignore, core, term, handle } act;

  sighandler_t handler;

  sigset_t pending;

  int ss_suspended;

  /* Reply to this sig_post message.  */

  __typeof (__msg_sig_post_reply) *reply_rpc

    = (untraced ? __msg_sig_post_untraced_reply : __msg_sig_post_reply);

  void reply (void)

    {

      error_t err;

      if (reply_port == MACH_PORT_NULL)

	return;

      err = (*reply_rpc) (reply_port, reply_port_type, 0);

      reply_port = MACH_PORT_NULL;

      if (err != MACH_SEND_INVALID_DEST) /* Ignore dead reply port.  */

	assert_perror (err);

    }

  /* Mark the signal as pending.  */

  void mark_pending (void)

    {

      __sigaddset (&ss->pending, signo);

      /* Save the details to be given to the handler when SIGNO is

	 unblocked.  */

      ss->pending_data[signo] = *detail;

    }

  /* Suspend the process with SIGNO.  */

  void suspend (void)

    {

      /* Stop all other threads and mark ourselves stopped.  */

      __USEPORT (PROC,

		 ({

		   /* Hold the siglock while stopping other threads to be

		      sure it is not held by another thread afterwards.  */

		   __mutex_lock (&_hurd_siglock);

		   __proc_dostop (port, _hurd_msgport_thread);

		   __mutex_unlock (&_hurd_siglock);

		   abort_all_rpcs (signo, &thread_state, 1);

		   reply ();

		   __proc_mark_stop (port, signo, detail->code);

		 }));

      _hurd_stopped = 1;

    }

  /* Resume the process after a suspension.  */

  void resume (void)

    {

      /* Resume the process from being stopped.  */

      thread_t *threads;

      mach_msg_type_number_t nthreads, i;

      error_t err;

      if (! _hurd_stopped)

	return;

      /* Tell the proc server we are continuing.  */

      __USEPORT (PROC, __proc_mark_cont (port));

      /* Fetch ports to all our threads and resume them.  */

      err = __task_threads (__mach_task_self (), &threads, &nthreads);

      assert_perror (err);

      for (i = 0; i < nthreads; ++i)

	{

	  if (threads[i] != _hurd_msgport_thread &&

	      (act != handle || threads[i] != ss->thread))

	    {

	      err = __thread_resume (threads[i]);

	      assert_perror (err);

	    }

	  err = __mach_port_deallocate (__mach_task_self (),

					threads[i]);

	  assert_perror (err);

	}

      __vm_deallocate (__mach_task_self (),

		       (vm_address_t) threads,

		       nthreads * sizeof *threads);

      _hurd_stopped = 0;

      if (act == handle)

	/* The thread that will run the handler is already suspended.  */

	ss_suspended = 1;

    }

  if (signo == 0)

    {

      if (untraced)

	/* This is PTRACE_CONTINUE.  */

	resume ();

      /* This call is just to check for pending signals.  */

      __spin_lock (&ss->lock);

      goto check_pending_signals;

    }

 post_signal:

  thread_state.set = 0;		/* We know nothing.  */

  __spin_lock (&ss->lock);

  /* Check for a preempted signal.  Preempted signals can arrive during

     critical sections.  */

  {

    inline sighandler_t try_preemptor (struct hurd_signal_preemptor *pe)

      {				/* PE cannot be null.  */

	do

	  {

	    if (HURD_PREEMPT_SIGNAL_P (pe, signo, detail->code))

	      {

		if (pe->preemptor)

		  {

		    sighandler_t handler = (*pe->preemptor) (pe, ss,

							     &signo, detail);

		    if (handler != SIG_ERR)

		      return handler;

		  }

		else

		  return pe->handler;

	      }

	    pe = pe->next;

	  } while (pe != 0);

	return SIG_ERR;

      }

    handler = ss->preemptors ? try_preemptor (ss->preemptors) : SIG_ERR;

    /* If no thread-specific preemptor, check for a global one.  */

    if (handler == SIG_ERR && __sigismember (&_hurdsig_preempted_set, signo))

      {

	__mutex_lock (&_hurd_siglock);

	handler = try_preemptor (_hurdsig_preemptors);

	__mutex_unlock (&_hurd_siglock);

      }

  }

  ss_suspended = 0;

  if (handler == SIG_IGN)

    /* Ignore the signal altogether.  */

    act = ignore;

  else if (handler != SIG_ERR)

    /* Run the preemption-provided handler.  */

    act = handle;

  else

    {

      /* No preemption.  Do normal handling.  */

      if (!untraced && __sigismember (&_hurdsig_traced, signo))

	{

	  /* We are being traced.  Stop to tell the debugger of the signal.  */

	  if (_hurd_stopped)

	    /* Already stopped.  Mark the signal as pending;

	       when resumed, we will notice it and stop again.  */

	    mark_pending ();

	  else

	    suspend ();

	  __spin_unlock (&ss->lock);

	  reply ();

	  return;

	}

      handler = ss->actions[signo].sa_handler;

      if (handler == SIG_DFL)

	/* Figure out the default action for this signal.  */

	switch (signo)

	  {

	  case 0:

	    /* A sig_post msg with SIGNO==0 is sent to

	       tell us to check for pending signals.  */

	    act = ignore;

	    break;

	  case SIGTTIN:

	  case SIGTTOU:

	  case SIGSTOP:

	  case SIGTSTP:

	    act = stop;

	    break;

	  case SIGCONT:

	  case SIGIO:

	  case SIGURG:

	  case SIGCHLD:

	  case SIGWINCH:

	    act = ignore;

	    break;

	  case SIGQUIT:

	  case SIGILL:

	  case SIGTRAP:

	  case SIGIOT:

	  case SIGEMT:

	  case SIGFPE:

	  case SIGBUS:

	  case SIGSEGV:

	  case SIGSYS:

	    act = core;

	    break;

	  case SIGINFO:

	    if (_hurd_pgrp == _hurd_pid)

	      {

		/* We are the process group leader.  Since there is no

		   user-specified handler for SIGINFO, we use a default one

		   which prints something interesting.  We use the normal

		   handler mechanism instead of just doing it here to avoid

		   the signal thread faulting or blocking in this

		   potentially hairy operation.  */

		act = handle;

		handler = _hurd_siginfo_handler;

	      }

	    else

	      act = ignore;

	    break;

	  default:

	    act = term;

	    break;

	  }

      else if (handler == SIG_IGN)

	act = ignore;

      else

	act = handle;

      if (__sigmask (signo) & STOPSIGS)

	/* Stop signals clear a pending SIGCONT even if they

	   are handled or ignored (but not if preempted).  */

	__sigdelset (&ss->pending, SIGCONT);

      else

	{

	  if (signo == SIGCONT)

	    /* Even if handled or ignored (but not preempted), SIGCONT clears

	       stop signals and resumes the process.  */

	    ss->pending &= ~STOPSIGS;

	  if (_hurd_stopped && act != stop && (untraced || signo == SIGCONT))

	    resume ();

	}

    }

  if (_hurd_orphaned && act == stop &&

      (__sigmask (signo) & (__sigmask (SIGTTIN) | __sigmask (SIGTTOU) |

			    __sigmask (SIGTSTP))))

    {

      /* If we would ordinarily stop for a job control signal, but we are

	 orphaned so noone would ever notice and continue us again, we just

	 quietly die, alone and in the dark.  */

      detail->code = signo;

      signo = SIGKILL;

      act = term;

    }

  /* Handle receipt of a blocked signal, or any signal while stopped.  */

  if (act != ignore &&		/* Signals ignored now are forgotten now.  */

      __sigismember (&ss->blocked, signo) ||

      (signo != SIGKILL && _hurd_stopped))

    {

      mark_pending ();

      act = ignore;

    }

  /* Perform the chosen action for the signal.  */

  switch (act)

    {

    case stop:

      if (_hurd_stopped)

	{

	  /* We are already stopped, but receiving an untraced stop

	     signal.  Instead of resuming and suspending again, just

	     notify the proc server of the new stop signal.  */

	  error_t err = __USEPORT (PROC, __proc_mark_stop

				   (port, signo, detail->code));

	  assert_perror (err);

	}

      else

	/* Suspend the process.  */

	suspend ();

      break;

    case ignore:

      if (detail->exc)

	/* Blocking or ignoring a machine exception is fatal.

	   Otherwise we could just spin on the faulting instruction.  */

	goto fatal;

      /* Nobody cares about this signal.  If there was a call to resume

	 above in SIGCONT processing and we've left a thread suspended,

	 now's the time to set it going. */

      if (ss_suspended)

	{

	  err = __thread_resume (ss->thread);

	  assert_perror (err);

	  ss_suspended = 0;

	}

      break;

    sigbomb:

      /* We got a fault setting up the stack frame for the handler.

	 Nothing to do but die; BSD gets SIGILL in this case.  */

      detail->code = signo;	/* XXX ? */

      signo = SIGILL;

    fatal:

      act = core;

      /* FALLTHROUGH */

    case term:			/* Time to die.  */

    case core:			/* And leave a rotting corpse.  */

      /* Have the proc server stop all other threads in our task.  */

      err = __USEPORT (PROC, __proc_dostop (port, _hurd_msgport_thread));

      assert_perror (err);

      /* No more user instructions will be executed.

	 The signal can now be considered delivered.  */

      reply ();

      /* Abort all server operations now in progress.  */

      abort_all_rpcs (signo, &thread_state, 0);

      {

	int status = W_EXITCODE (0, signo);

	/* Do a core dump if desired.  Only set the wait status bit saying we

	   in fact dumped core if the operation was actually successful.  */

	if (act == core && write_corefile (signo, detail))

	  status |= WCOREFLAG;

	/* Tell proc how we died and then stick the saber in the gut.  */

	_hurd_exit (status);

	/* NOTREACHED */

      }

    case handle:

      /* Call a handler for this signal.  */

      {

	struct sigcontext *scp, ocontext;

	int wait_for_reply, state_changed;

	/* Stop the thread and abort its pending RPC operations.  */

	if (! ss_suspended)

	  {

	    err = __thread_suspend (ss->thread);

	    assert_perror (err);

	  }

	/* Abort the thread's kernel context, so any pending message send

	   or receive completes immediately or aborts.  If an interruptible

	   RPC is in progress, abort_rpcs will do this.  But we must always

	   do it before fetching the thread's state, because

	   thread_get_state is never kosher before thread_abort.  */

	abort_thread (ss, &thread_state, NULL);

	if (ss->context)

	  {

	    /* We have a previous sigcontext that sigreturn was about

	       to restore when another signal arrived.  */

	    mach_port_t *loc;

	    if (_hurdsig_catch_memory_fault (ss->context))

	      {

		/* 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

		   problem.  */

		ss->context = NULL;

	      }

	    else

	      {

		/* Copy the context from the thread's stack before

		   we start diddling the stack to set up the handler.  */

		ocontext = *ss->context;

		ss->context = &ocontext;

	      }

	    _hurdsig_end_catch_fault ();

	    if (! machine_get_basic_state (ss->thread, &thread_state))

	      goto sigbomb;

	    loc = interrupted_reply_port_location (ss->thread,

						   &thread_state, 1);

	    if (loc && *loc != MACH_PORT_NULL)

	      /* This is the reply port for the context which called

		 sigreturn.  Since we are abandoning that context entirely

		 and restoring SS->context instead, destroy this port.  */

	      __mach_port_destroy (__mach_task_self (), *loc);

	    /* The thread was in sigreturn, not in any interruptible RPC.  */

	    wait_for_reply = 0;

	    assert (! __spin_lock_locked (&ss->critical_section_lock));

	  }

	else

	  {

	    int crit = __spin_lock_locked (&ss->critical_section_lock);

	    wait_for_reply

	      = (_hurdsig_abort_rpcs (ss,

				      /* In a critical section, any RPC

					 should be cancelled instead of

					 restarted, regardless of

					 SA_RESTART, so the entire

					 "atomic" operation can be aborted

					 as a unit.  */

				      crit ? 0 : signo, 1,

				      &thread_state, &state_changed,

				      &reply)

		 != MACH_PORT_NULL);

	    if (crit)

	      {