ap/libc/glibc/glibc-2.23/hurd/hurdexec.c - T106_DC - Gitiles

 /* Copyright (C) 1991-2016 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 <errno.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 #include <hurd.h>
 #include <hurd/fd.h>
 #include <hurd/signal.h>
 #include <hurd/id.h>
 #include <assert.h>
 #include <argz.h>

 /* Overlay TASK, executing FILE with arguments ARGV and environment ENVP.
    If TASK == mach_task_self (), some ports are dealloc'd by the exec server.
    ARGV and ENVP are terminated by NULL pointers.  */
 error_t
 _hurd_exec (task_t task, file_t file,
 	    char *const argv[], char *const envp[])
 {
   error_t err;
   char *args, *env;
   size_t argslen, envlen;
   int ints[INIT_INT_MAX];
   mach_port_t ports[_hurd_nports];
   struct hurd_userlink ulink_ports[_hurd_nports];
   inline void free_port (unsigned int i)
     {
       _hurd_port_free (&_hurd_ports[i], &ulink_ports[i], ports[i]);
     }
   file_t *dtable;
   unsigned int dtablesize, i;
   struct hurd_port **dtable_cells;
   struct hurd_userlink *ulink_dtable;
   struct hurd_sigstate *ss;
   mach_port_t *please_dealloc, *pdp;
   int reauth = 0;

   /* XXX needs to be hurdmalloc XXX */
   if (argv == NULL)
     args = NULL, argslen = 0;
   else if (err = __argz_create (argv, &args, &argslen))
     return err;
   if (envp == NULL)
     env = NULL, envlen = 0;
   else if (err = __argz_create (envp, &env, &envlen))
     goto outargs;

   /* Load up the ports to give to the new program.  */
   for (i = 0; i < _hurd_nports; ++i)
     if (i == INIT_PORT_PROC && task != __mach_task_self ())
       {
 	/* This is another task, so we need to ask the proc server
 	   for the right proc server port for it.  */
 	if (err = __USEPORT (PROC, __proc_task2proc (port, task, &ports[i])))
 	  {
 	    while (--i > 0)
 	      free_port (i);
 	    goto outenv;
 	  }
       }
     else
       ports[i] = _hurd_port_get (&_hurd_ports[i], &ulink_ports[i]);


   /* Load up the ints to give the new program.  */
   for (i = 0; i < INIT_INT_MAX; ++i)
     switch (i)
       {
       case INIT_UMASK:
 	ints[i] = _hurd_umask;
 	break;

       case INIT_SIGMASK:
       case INIT_SIGIGN:
       case INIT_SIGPENDING:
 	/* We will set these all below.  */
 	break;

       case INIT_TRACEMASK:
 	ints[i] = _hurdsig_traced;
 	break;

       default:
 	ints[i] = 0;
       }

   ss = _hurd_self_sigstate ();

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

   __spin_lock (&ss->lock);
   ints[INIT_SIGMASK] = ss->blocked;
   ints[INIT_SIGPENDING] = ss->pending;
   ints[INIT_SIGIGN] = 0;
   for (i = 1; i < NSIG; ++i)
     if (ss->actions[i].sa_handler == SIG_IGN)
       ints[INIT_SIGIGN] |= __sigmask (i);

   /* We hold the sigstate lock until the exec has failed so that no signal
      can arrive between when we pack the blocked and ignored signals, and
      when the exec actually happens.  A signal handler could change what
      signals are blocked and ignored.  Either the change will be reflected
      in the exec, or the signal will never be delivered.  Setting the
      critical section flag avoids anything we call trying to acquire the
      sigstate lock.  */

   __spin_unlock (&ss->lock);

   /* Pack up the descriptor table to give the new program.  */
   __mutex_lock (&_hurd_dtable_lock);

   dtablesize = _hurd_dtable ? _hurd_dtablesize : _hurd_init_dtablesize;

   if (task == __mach_task_self ())
     /* Request the exec server to deallocate some ports from us if the exec
        succeeds.  The init ports and descriptor ports will arrive in the
        new program's exec_startup message.  If we failed to deallocate
        them, the new program would have duplicate user references for them.
        But we cannot deallocate them ourselves, because we must still have
        them after a failed exec call.  */
     please_dealloc = __alloca ((_hurd_nports + 3 + (3 * dtablesize))
 				* sizeof (mach_port_t));
   else
     please_dealloc = NULL;
   pdp = please_dealloc;

   if (_hurd_dtable != NULL)
     {
       dtable = __alloca (dtablesize * sizeof (dtable[0]));
       ulink_dtable = __alloca (dtablesize * sizeof (ulink_dtable[0]));
       dtable_cells = __alloca (dtablesize * sizeof (dtable_cells[0]));
       for (i = 0; i < dtablesize; ++i)
 	{
 	  struct hurd_fd *const d = _hurd_dtable[i];
 	  if (d == NULL)
 	    {
 	      dtable[i] = MACH_PORT_NULL;
 	      continue;
 	    }
 	  __spin_lock (&d->port.lock);
 	  if (d->flags & FD_CLOEXEC)
 	    {
 	      /* This descriptor is marked to be closed on exec.
 		 So don't pass it to the new program.  */
 	      dtable[i] = MACH_PORT_NULL;
 	      if (pdp && d->port.port != MACH_PORT_NULL)
 		{
 		  /* We still need to deallocate the ports.  */
 		  *pdp++ = d->port.port;
 		  if (d->ctty.port != MACH_PORT_NULL)
 		    *pdp++ = d->ctty.port;
 		}
 	      __spin_unlock (&d->port.lock);
 	    }
 	  else
 	    {
 	      if (pdp && d->ctty.port != MACH_PORT_NULL)
 		/* All the elements of DTABLE are added to PLEASE_DEALLOC
 		   below, so we needn't add the port itself.
 		   But we must deallocate the ctty port as well as
 		   the normal port that got installed in DTABLE[I].  */
 		*pdp++ = d->ctty.port;
 	      dtable[i] = _hurd_port_locked_get (&d->port, &ulink_dtable[i]);
 	      dtable_cells[i] = &d->port;
 	    }
 	}
     }
   else
     {
       dtable = _hurd_init_dtable;
       ulink_dtable = NULL;
       dtable_cells = NULL;
     }

   /* Prune trailing null ports from the descriptor table.  */
   while (dtablesize > 0 && dtable[dtablesize - 1] == MACH_PORT_NULL)
     --dtablesize;

   /* See if we need to diddle the auth port of the new program.
      The purpose of this is to get the effect setting the saved-set UID and
      GID to the respective effective IDs after the exec, as POSIX.1 requires.
      Note that we don't reauthenticate with the proc server; that would be a
      no-op since it only keeps track of the effective UIDs, and if it did
      keep track of the available IDs we would have the problem that we'd be
      changing the IDs before the exec and have to change them back after a
      failure.  Arguably we could skip all the reauthentications because the
      available IDs have no bearing on any filesystem.  But the conservative
      approach is to reauthenticate all the io ports so that no state anywhere
      reflects that our whole ID set differs from what we've set it to.  */
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
   if (err == 0 && ((_hurd_id.aux.nuids >= 2 && _hurd_id.gen.nuids >= 1
 		    && _hurd_id.aux.uids[1] != _hurd_id.gen.uids[0])
 		   || (_hurd_id.aux.ngids >= 2 && _hurd_id.gen.ngids >= 1
 		       && _hurd_id.aux.gids[1] != _hurd_id.gen.gids[0])))
     {
       /* We have euid != svuid or egid != svgid.  POSIX.1 says that exec
 	 sets svuid = euid and svgid = egid.  So we must get a new auth
 	 port and reauthenticate everything with it.  We'll pass the new
 	 ports in file_exec instead of our own ports.  */

       auth_t newauth;

       _hurd_id.aux.uids[1] = _hurd_id.gen.uids[0];
       _hurd_id.aux.gids[1] = _hurd_id.gen.gids[0];
       _hurd_id.valid = 0;
       if (_hurd_id.rid_auth != MACH_PORT_NULL)
 	{
 	  __mach_port_deallocate (__mach_task_self (), _hurd_id.rid_auth);
 	  _hurd_id.rid_auth = MACH_PORT_NULL;
 	}

       err = __auth_makeauth (ports[INIT_PORT_AUTH],
 			     NULL, MACH_MSG_TYPE_COPY_SEND, 0,
 			     _hurd_id.gen.uids, _hurd_id.gen.nuids,
 			     _hurd_id.aux.uids, _hurd_id.aux.nuids,
 			     _hurd_id.gen.gids, _hurd_id.gen.ngids,
 			     _hurd_id.aux.gids, _hurd_id.aux.ngids,
 			     &newauth);
       if (err == 0)
 	{
 	  /* Now we have to reauthenticate the ports with this new ID.
 	   */

 	  inline error_t reauth_io (io_t port, io_t *newport)
 	    {
 	      mach_port_t ref = __mach_reply_port ();
 	      *newport = MACH_PORT_NULL;
 	      error_t err = __io_reauthenticate (port,
 						 ref, MACH_MSG_TYPE_MAKE_SEND);
 	      if (!err)
 		err = __auth_user_authenticate (newauth,
 						ref, MACH_MSG_TYPE_MAKE_SEND,
 						newport);
 	      __mach_port_destroy (__mach_task_self (), ref);
 	      return err;
 	    }
 	  inline void reauth_port (unsigned int idx)
 	    {
 	      io_t newport;
 	      err = reauth_io (ports[idx], &newport) ?: err;
 	      if (pdp)
 		*pdp++ = ports[idx]; /* XXX presumed still in _hurd_ports */
 	      free_port (idx);
 	      ports[idx] = newport;
 	    }

 	  if (pdp)
 	    *pdp++ = ports[INIT_PORT_AUTH];
 	  free_port (INIT_PORT_AUTH);
 	  ports[INIT_PORT_AUTH] = newauth;

 	  reauth_port (INIT_PORT_CRDIR);
 	  reauth_port (INIT_PORT_CWDIR);

 	  if (!err)
 	    {
 	      /* Now we'll reauthenticate each file descriptor.  */
 	      if (ulink_dtable == NULL)
 		{
 		  assert (dtable == _hurd_init_dtable);
 		  dtable = __alloca (dtablesize * sizeof (dtable[0]));
 		  for (i = 0; i < dtablesize; ++i)
 		    if (_hurd_init_dtable[i] != MACH_PORT_NULL)
 		      {
 			if (pdp)
 			  *pdp++ = _hurd_init_dtable[i];
 			err = reauth_io (_hurd_init_dtable[i], &dtable[i]);
 			if (err)
 			  {
 			    while (++i < dtablesize)
 			      dtable[i] = MACH_PORT_NULL;
 			    break;
 			  }
 		      }
 		    else
 		      dtable[i] = MACH_PORT_NULL;
 		}
 	      else
 		{
 		  if (pdp)
 		    {
 		      /* Ask to deallocate all the old fd ports,
 			 since we will have new ones in DTABLE.  */
 		      memcpy (pdp, dtable, dtablesize * sizeof pdp[0]);
 		      pdp += dtablesize;
 		    }
 		  for (i = 0; i < dtablesize; ++i)
 		    if (dtable[i] != MACH_PORT_NULL)
 		      {
 			io_t newport;
 			err = reauth_io (dtable[i], &newport);
 			_hurd_port_free (dtable_cells[i], &ulink_dtable[i],
 					 dtable[i]);
 			dtable[i] = newport;
 			if (err)
 			  {
 			    while (++i < dtablesize)
 			      _hurd_port_free (dtable_cells[i],
 					       &ulink_dtable[i], dtable[i]);
 			    break;
 			  }
 		      }
 		  ulink_dtable = NULL;
 		  dtable_cells = NULL;
 		}
 	    }
 	}

       reauth = 1;
     }
   __mutex_unlock (&_hurd_id.lock);

   /* The information is all set up now.  Try to exec the file.  */
   if (!err)
     {
       int flags;

       if (pdp)
 	{
 	  /* Request the exec server to deallocate some ports from us if
 	     the exec succeeds.  The init ports and descriptor ports will
 	     arrive in the new program's exec_startup message.  If we
 	     failed to deallocate them, the new program would have
 	     duplicate user references for them.  But we cannot deallocate
 	     them ourselves, because we must still have them after a failed
 	     exec call.  */

 	  for (i = 0; i < _hurd_nports; ++i)
 	    *pdp++ = ports[i];
 	  for (i = 0; i < dtablesize; ++i)
 	    *pdp++ = dtable[i];
 	}

       flags = 0;
 #ifdef EXEC_SIGTRAP
       /* PTRACE_TRACEME sets all bits in _hurdsig_traced, which is
 	 propagated through exec by INIT_TRACEMASK, so this checks if
 	 PTRACE_TRACEME has been called in this process in any of its
 	 current or prior lives.  */
       if (__sigismember (&_hurdsig_traced, SIGKILL))
 	flags |= EXEC_SIGTRAP;
 #endif
       err = __file_exec (file, task, flags,
 			 args, argslen, env, envlen,
 			 dtable, MACH_MSG_TYPE_COPY_SEND, dtablesize,
 			 ports, MACH_MSG_TYPE_COPY_SEND, _hurd_nports,
 			 ints, INIT_INT_MAX,
 			 please_dealloc, pdp - please_dealloc,
 			 &_hurd_msgport, task == __mach_task_self () ? 1 : 0);
     }

   /* Release references to the standard ports.  */
   for (i = 0; i < _hurd_nports; ++i)
     if ((i == INIT_PORT_PROC && task != __mach_task_self ())
 	|| (reauth && (i == INIT_PORT_AUTH
 		       || i == INIT_PORT_CRDIR || i == INIT_PORT_CWDIR)))
       __mach_port_deallocate (__mach_task_self (), ports[i]);
     else
       free_port (i);

   /* Release references to the file descriptor ports.  */
   if (ulink_dtable != NULL)
     {
       for (i = 0; i < dtablesize; ++i)
 	if (dtable[i] != MACH_PORT_NULL)
 	  _hurd_port_free (dtable_cells[i], &ulink_dtable[i], dtable[i]);
     }
   else if (dtable && dtable != _hurd_init_dtable)
     for (i = 0; i < dtablesize; ++i)
       __mach_port_deallocate (__mach_task_self (), dtable[i]);

   /* Release lock on the file descriptor table. */
   __mutex_unlock (&_hurd_dtable_lock);

   /* Safe to let signals happen now.  */
   _hurd_critical_section_unlock (ss);

  outargs:
   free (args);
  outenv:
   free (env);
   return err;
 }
	/* Copyright (C) 1991-2016 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 <errno.h>
	#include <unistd.h>
	#include <fcntl.h>
	#include <limits.h>
	#include <stdlib.h>
	#include <string.h>
	#include <hurd.h>
	#include <hurd/fd.h>
	#include <hurd/signal.h>
	#include <hurd/id.h>
	#include <assert.h>
	#include <argz.h>

	/* Overlay TASK, executing FILE with arguments ARGV and environment ENVP.
	If TASK == mach_task_self (), some ports are dealloc'd by the exec server.
	ARGV and ENVP are terminated by NULL pointers. */
	error_t
	_hurd_exec (task_t task, file_t file,
	char const argv[], char const envp[])
	{
	error_t err;
	char args, env;
	size_t argslen, envlen;
	int ints[INIT_INT_MAX];
	mach_port_t ports[_hurd_nports];
	struct hurd_userlink ulink_ports[_hurd_nports];
	inline void free_port (unsigned int i)
	{
	_hurd_port_free (&_hurd_ports[i], &ulink_ports[i], ports[i]);
	}
	file_t *dtable;
	unsigned int dtablesize, i;
	struct hurd_port **dtable_cells;
	struct hurd_userlink *ulink_dtable;
	struct hurd_sigstate *ss;
	mach_port_t please_dealloc, pdp;
	int reauth = 0;

	/* XXX needs to be hurdmalloc XXX */
	if (argv == NULL)
	args = NULL, argslen = 0;
	else if (err = __argz_create (argv, &args, &argslen))
	return err;
	if (envp == NULL)
	env = NULL, envlen = 0;
	else if (err = __argz_create (envp, &env, &envlen))
	goto outargs;

	/* Load up the ports to give to the new program. */
	for (i = 0; i < _hurd_nports; ++i)
	if (i == INIT_PORT_PROC && task != __mach_task_self ())
	{
	/* This is another task, so we need to ask the proc server
	for the right proc server port for it. */
	if (err = __USEPORT (PROC, __proc_task2proc (port, task, &ports[i])))
	{
	while (--i > 0)
	free_port (i);
	goto outenv;
	}
	}
	else
	ports[i] = _hurd_port_get (&_hurd_ports[i], &ulink_ports[i]);


	/* Load up the ints to give the new program. */
	for (i = 0; i < INIT_INT_MAX; ++i)
	switch (i)
	{
	case INIT_UMASK:
	ints[i] = _hurd_umask;
	break;

	case INIT_SIGMASK:
	case INIT_SIGIGN:
	case INIT_SIGPENDING:
	/* We will set these all below. */
	break;

	case INIT_TRACEMASK:
	ints[i] = _hurdsig_traced;
	break;

	default:
	ints[i] = 0;
	}

	ss = _hurd_self_sigstate ();

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

	__spin_lock (&ss->lock);
	ints[INIT_SIGMASK] = ss->blocked;
	ints[INIT_SIGPENDING] = ss->pending;
	ints[INIT_SIGIGN] = 0;
	for (i = 1; i < NSIG; ++i)
	if (ss->actions[i].sa_handler == SIG_IGN)
	ints[INIT_SIGIGN] \|= __sigmask (i);

	/* We hold the sigstate lock until the exec has failed so that no signal
	can arrive between when we pack the blocked and ignored signals, and
	when the exec actually happens. A signal handler could change what
	signals are blocked and ignored. Either the change will be reflected
	in the exec, or the signal will never be delivered. Setting the
	critical section flag avoids anything we call trying to acquire the
	sigstate lock. */

	__spin_unlock (&ss->lock);

	/* Pack up the descriptor table to give the new program. */
	__mutex_lock (&_hurd_dtable_lock);

	dtablesize = _hurd_dtable ? _hurd_dtablesize : _hurd_init_dtablesize;

	if (task == __mach_task_self ())
	/* Request the exec server to deallocate some ports from us if the exec
	succeeds. The init ports and descriptor ports will arrive in the
	new program's exec_startup message. If we failed to deallocate
	them, the new program would have duplicate user references for them.
	But we cannot deallocate them ourselves, because we must still have
	them after a failed exec call. */
	please_dealloc = __alloca ((_hurd_nports + 3 + (3 * dtablesize))
	* sizeof (mach_port_t));
	else
	please_dealloc = NULL;
	pdp = please_dealloc;

	if (_hurd_dtable != NULL)
	{
	dtable = __alloca (dtablesize * sizeof (dtable[0]));
	ulink_dtable = __alloca (dtablesize * sizeof (ulink_dtable[0]));
	dtable_cells = __alloca (dtablesize * sizeof (dtable_cells[0]));
	for (i = 0; i < dtablesize; ++i)
	{
	struct hurd_fd *const d = _hurd_dtable[i];
	if (d == NULL)
	{
	dtable[i] = MACH_PORT_NULL;
	continue;
	}
	__spin_lock (&d->port.lock);
	if (d->flags & FD_CLOEXEC)
	{
	/* This descriptor is marked to be closed on exec.
	So don't pass it to the new program. */
	dtable[i] = MACH_PORT_NULL;
	if (pdp && d->port.port != MACH_PORT_NULL)
	{
	/* We still need to deallocate the ports. */
	*pdp++ = d->port.port;
	if (d->ctty.port != MACH_PORT_NULL)
	*pdp++ = d->ctty.port;
	}
	__spin_unlock (&d->port.lock);
	}
	else
	{
	if (pdp && d->ctty.port != MACH_PORT_NULL)
	/* All the elements of DTABLE are added to PLEASE_DEALLOC
	below, so we needn't add the port itself.
	But we must deallocate the ctty port as well as
	the normal port that got installed in DTABLE[I]. */
	*pdp++ = d->ctty.port;
	dtable[i] = _hurd_port_locked_get (&d->port, &ulink_dtable[i]);
	dtable_cells[i] = &d->port;
	}
	}
	}
	else
	{
	dtable = _hurd_init_dtable;
	ulink_dtable = NULL;
	dtable_cells = NULL;
	}

	/* Prune trailing null ports from the descriptor table. */
	while (dtablesize > 0 && dtable[dtablesize - 1] == MACH_PORT_NULL)
	--dtablesize;

	/* See if we need to diddle the auth port of the new program.
	The purpose of this is to get the effect setting the saved-set UID and
	GID to the respective effective IDs after the exec, as POSIX.1 requires.
	Note that we don't reauthenticate with the proc server; that would be a
	no-op since it only keeps track of the effective UIDs, and if it did
	keep track of the available IDs we would have the problem that we'd be
	changing the IDs before the exec and have to change them back after a
	failure. Arguably we could skip all the reauthentications because the
	available IDs have no bearing on any filesystem. But the conservative
	approach is to reauthenticate all the io ports so that no state anywhere
	reflects that our whole ID set differs from what we've set it to. */
	__mutex_lock (&_hurd_id.lock);
	err = _hurd_check_ids ();
	if (err == 0 && ((_hurd_id.aux.nuids >= 2 && _hurd_id.gen.nuids >= 1
	&& _hurd_id.aux.uids[1] != _hurd_id.gen.uids[0])
	\|\| (_hurd_id.aux.ngids >= 2 && _hurd_id.gen.ngids >= 1
	&& _hurd_id.aux.gids[1] != _hurd_id.gen.gids[0])))
	{
	/* We have euid != svuid or egid != svgid. POSIX.1 says that exec
	sets svuid = euid and svgid = egid. So we must get a new auth
	port and reauthenticate everything with it. We'll pass the new
	ports in file_exec instead of our own ports. */

	auth_t newauth;

	_hurd_id.aux.uids[1] = _hurd_id.gen.uids[0];
	_hurd_id.aux.gids[1] = _hurd_id.gen.gids[0];
	_hurd_id.valid = 0;
	if (_hurd_id.rid_auth != MACH_PORT_NULL)
	{
	__mach_port_deallocate (__mach_task_self (), _hurd_id.rid_auth);
	_hurd_id.rid_auth = MACH_PORT_NULL;
	}

	err = __auth_makeauth (ports[INIT_PORT_AUTH],
	NULL, MACH_MSG_TYPE_COPY_SEND, 0,
	_hurd_id.gen.uids, _hurd_id.gen.nuids,
	_hurd_id.aux.uids, _hurd_id.aux.nuids,
	_hurd_id.gen.gids, _hurd_id.gen.ngids,
	_hurd_id.aux.gids, _hurd_id.aux.ngids,
	&newauth);
	if (err == 0)
	{
	/* Now we have to reauthenticate the ports with this new ID.
	*/

	inline error_t reauth_io (io_t port, io_t *newport)
	{
	mach_port_t ref = __mach_reply_port ();
	*newport = MACH_PORT_NULL;
	error_t err = __io_reauthenticate (port,
	ref, MACH_MSG_TYPE_MAKE_SEND);
	if (!err)
	err = __auth_user_authenticate (newauth,
	ref, MACH_MSG_TYPE_MAKE_SEND,
	newport);
	__mach_port_destroy (__mach_task_self (), ref);
	return err;
	}
	inline void reauth_port (unsigned int idx)
	{
	io_t newport;
	err = reauth_io (ports[idx], &newport) ?: err;
	if (pdp)
	pdp++ = ports[idx]; / XXX presumed still in _hurd_ports */
	free_port (idx);
	ports[idx] = newport;
	}

	if (pdp)
	*pdp++ = ports[INIT_PORT_AUTH];
	free_port (INIT_PORT_AUTH);
	ports[INIT_PORT_AUTH] = newauth;

	reauth_port (INIT_PORT_CRDIR);
	reauth_port (INIT_PORT_CWDIR);

	if (!err)
	{
	/* Now we'll reauthenticate each file descriptor. */
	if (ulink_dtable == NULL)
	{
	assert (dtable == _hurd_init_dtable);
	dtable = __alloca (dtablesize * sizeof (dtable[0]));
	for (i = 0; i < dtablesize; ++i)
	if (_hurd_init_dtable[i] != MACH_PORT_NULL)
	{
	if (pdp)
	*pdp++ = _hurd_init_dtable[i];
	err = reauth_io (_hurd_init_dtable[i], &dtable[i]);
	if (err)
	{
	while (++i < dtablesize)
	dtable[i] = MACH_PORT_NULL;
	break;
	}
	}
	else
	dtable[i] = MACH_PORT_NULL;
	}
	else
	{
	if (pdp)
	{
	/* Ask to deallocate all the old fd ports,
	since we will have new ones in DTABLE. */
	memcpy (pdp, dtable, dtablesize * sizeof pdp[0]);
	pdp += dtablesize;
	}
	for (i = 0; i < dtablesize; ++i)
	if (dtable[i] != MACH_PORT_NULL)
	{
	io_t newport;
	err = reauth_io (dtable[i], &newport);
	_hurd_port_free (dtable_cells[i], &ulink_dtable[i],
	dtable[i]);
	dtable[i] = newport;
	if (err)
	{
	while (++i < dtablesize)
	_hurd_port_free (dtable_cells[i],
	&ulink_dtable[i], dtable[i]);
	break;
	}
	}
	ulink_dtable = NULL;
	dtable_cells = NULL;
	}
	}
	}

	reauth = 1;
	}
	__mutex_unlock (&_hurd_id.lock);

	/* The information is all set up now. Try to exec the file. */
	if (!err)
	{
	int flags;

	if (pdp)
	{
	/* Request the exec server to deallocate some ports from us if
	the exec succeeds. The init ports and descriptor ports will
	arrive in the new program's exec_startup message. If we
	failed to deallocate them, the new program would have
	duplicate user references for them. But we cannot deallocate
	them ourselves, because we must still have them after a failed
	exec call. */

	for (i = 0; i < _hurd_nports; ++i)
	*pdp++ = ports[i];
	for (i = 0; i < dtablesize; ++i)
	*pdp++ = dtable[i];
	}

	flags = 0;
	#ifdef EXEC_SIGTRAP
	/* PTRACE_TRACEME sets all bits in _hurdsig_traced, which is
	propagated through exec by INIT_TRACEMASK, so this checks if
	PTRACE_TRACEME has been called in this process in any of its
	current or prior lives. */
	if (__sigismember (&_hurdsig_traced, SIGKILL))
	flags \|= EXEC_SIGTRAP;
	#endif
	err = __file_exec (file, task, flags,
	args, argslen, env, envlen,
	dtable, MACH_MSG_TYPE_COPY_SEND, dtablesize,
	ports, MACH_MSG_TYPE_COPY_SEND, _hurd_nports,
	ints, INIT_INT_MAX,
	please_dealloc, pdp - please_dealloc,
	&_hurd_msgport, task == __mach_task_self () ? 1 : 0);
	}

	/* Release references to the standard ports. */
	for (i = 0; i < _hurd_nports; ++i)
	if ((i == INIT_PORT_PROC && task != __mach_task_self ())
	\|\| (reauth && (i == INIT_PORT_AUTH
	\|\| i == INIT_PORT_CRDIR \|\| i == INIT_PORT_CWDIR)))
	__mach_port_deallocate (__mach_task_self (), ports[i]);
	else
	free_port (i);

	/* Release references to the file descriptor ports. */
	if (ulink_dtable != NULL)
	{
	for (i = 0; i < dtablesize; ++i)
	if (dtable[i] != MACH_PORT_NULL)
	_hurd_port_free (dtable_cells[i], &ulink_dtable[i], dtable[i]);
	}
	else if (dtable && dtable != _hurd_init_dtable)
	for (i = 0; i < dtablesize; ++i)
	__mach_port_deallocate (__mach_task_self (), dtable[i]);

	/* Release lock on the file descriptor table. */
	__mutex_unlock (&_hurd_dtable_lock);

	/* Safe to let signals happen now. */
	_hurd_critical_section_unlock (ss);

	outargs:
	free (args);
	outenv:
	free (env);
	return err;
	}