about summary refs log tree commit diff
path: root/hurd/hurdexec.c
blob: e18107b9a75d083288b291780a6a462aec5a5385 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <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>

/* 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, *ap;
  size_t argslen, envlen;
  int ints[INIT_INT_MAX];
  mach_port_t ports[_hurd_nports];
  struct hurd_userlink ulink_ports[_hurd_nports];
  file_t *dtable;
  unsigned int dtablesize, i;
  struct hurd_port **dtable_cells;
  struct hurd_userlink *ulink_dtable;
  char *const *p;
  struct hurd_sigstate *ss;
  mach_port_t *please_dealloc, *pdp;


  /* Pack the arguments into an array with nulls separating the elements.  */
  argslen = 0;
  if (argv != NULL)
    {
      p = argv;
      while (*p != NULL)
	argslen += strlen (*p++) + 1;
      args = __alloca (argslen);
      ap = args;
      for (p = argv; *p != NULL; ++p)
	ap = __memccpy (ap, *p, '\0', ULONG_MAX);
    }
  else
    args = NULL;

  /* Pack the environment into an array with nulls separating elements.  */
  envlen = 0;
  if (envp != NULL)
    {
      p = envp;
      while (*p != NULL)
	envlen += strlen (*p++) + 1;
      env = __alloca (envlen);
      ap = env;
      for (p = envp; *p != NULL; ++p)
	ap = __memccpy (ap, *p, '\0', ULONG_MAX);
    }
  else
    env = NULL;

  /* 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)
	      _hurd_port_free (&_hurd_ports[i], &ulink_ports[i], ports[i]);
	    return err;
	  }
      }
    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;

      default:
	ints[i] = 0;
      }

  ss = _hurd_self_sigstate ();
  __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.  */
  
  ss->critical_section = 1;
  __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 + (2 * 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;
    }

  /* The information is all set up now.  Try to exec the file.  */

  {
    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];
      }

    err = __file_exec (file, task,
		       _hurd_exec_flags & EXEC_INHERITED,
		       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,
		       NULL, 0);
  }

  /* Release references to the standard ports.  */
  for (i = 0; i < _hurd_nports; ++i)
    if (i == INIT_PORT_PROC && task != __mach_task_self ())
      __mach_port_deallocate (__mach_task_self (), ports[i]);
    else
      _hurd_port_free (&_hurd_ports[i], &ulink_ports[i], ports[i]);

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

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

  /* Safe to let signals happen now.  */
  {
    sigset_t pending;
    __spin_lock (&ss->lock);
    ss->critical_section = 0;
    pending = ss->pending & ~ss->blocked;
    __spin_unlock (&ss->lock);
    if (pending)
      __msg_sig_post (_hurd_msgport, 0, __mach_task_self ());
  }

  return err;
}