summaryrefslogtreecommitdiff
path: root/utils/settrans.c
blob: 399bd1281d5108ef15ebd8239d95d2298135e1df (plain)
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
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
/* Set a file's translator.

   Copyright (C) 1995,96,97,98,2001,02,13,14
     Free Software Foundation, Inc.
   Written by Miles Bader <miles@gnu.org>

   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, 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., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include <assert.h>
#include <hurd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <argp.h>
#include <error.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/wait.h>

#include <error.h>
#include <argz.h>
#include <hurd/fshelp.h>
#include <hurd/process.h>
#include <version.h>

#include <hurd/lookup.h>
#include <hurd/fsys.h>


const char *argp_program_version = STANDARD_HURD_VERSION (settrans);

#define DEFAULT_TIMEOUT 60

#define _STRINGIFY(arg) #arg
#define STRINGIFY(arg) _STRINGIFY (arg)

#define OPT_CHROOT_CHDIR	-1

static struct argp_option options[] =
{
  {"active",      'a', 0, 0, "Start TRANSLATOR and set it as NODE's active translator" },
  {"start",       's', 0, 0, "Start the translator specified by the NODE's passive translator record and set it as NODE's active translator" },
  {"passive",     'p', 0, 0, "Change NODE's passive translator record (default)" },
  {"create",      'c', 0, 0, "Create NODE if it doesn't exist" },
  {"dereference", 'L', 0, 0, "If a translator exists, put the new one on top"},
  {"pid-file",    'F', "FILENAME", 0, "When starting an active translator,"
     " write its pid to this file"},
  {"pause",       'P', 0, 0, "When starting an active translator, prompt and"
     " wait for a newline on stdin before completing the startup handshake"},
  {"timeout",     't',"SEC",0, "Timeout for translator startup, in seconds"
     " (default " STRINGIFY (DEFAULT_TIMEOUT) "); 0 means no timeout"},
  {"exclusive",   'x', 0, 0, "Only set the translator if there is not one already"},
  {"orphan",      'o', 0, 0, "Disconnect old translator from the filesystem "
			     "(do not ask it to go away)"},

  {"chroot",      'C', 0, 0,
   "Instead of setting the node's translator, take following arguments up to"
   " `--' and run that command chroot'd to the translated node."},
  {"chroot-chdir",      OPT_CHROOT_CHDIR, "DIR", 0,
   "Change to DIR before running the chrooted command.  "
   "DIR must be an absolute path."},

  {0,0,0,0, "When setting the passive translator, if there's an active translator:"},
  {"goaway",      'g', 0, 0, "Ask the active translator to go away"},
  {"keep-active", 'k', 0, 0, "Leave any existing active translator running"},

  {0,0,0,0, "When an active translator is told to go away:"},
  {"recursive",   'R', 0, 0, "Shutdown its children too"},
  {"force",       'f', 0, 0, "Ask it to ignore current users and shutdown "
			     "anyway." },
  {"nosync",      'S', 0, 0, "Don't sync it before killing it"},

  {0, 0}
};
static char *args_doc = "NODE [TRANSLATOR ARG...]";
static char *doc = "Set the passive/active translator on NODE."
"\vBy default the passive translator is set.";

/* Authentication of the current process.  */
uid_t *uids;
gid_t *gids;
size_t uids_len, gids_len;

/* Initialize and populate the uids and gids vectors.  */
error_t
get_credentials (void)
{
  /* Fetch uids...  */
  uids_len = geteuids (0, 0);
  if (uids_len < 0)
    return errno;

  uids = malloc (uids_len * sizeof (uid_t));
  if (! uids)
    return ENOMEM;

  uids_len = geteuids (uids_len, uids);
  if (uids_len < 0)
    return errno;

  /* ... and gids.  */
  gids_len = getgroups (0, 0);
  if (gids_len < 0)
    return errno;

  gids = malloc (gids_len * sizeof (gid_t));
  if (! uids)
    return ENOMEM;

  gids_len = getgroups (gids_len, gids);
  if (gids_len < 0)
    return errno;

  return 0;
}

/* ---------------------------------------------------------------- */

int
main(int argc, char *argv[])
{
  error_t err;

  /* The filesystem node we're putting a translator on.  */
  char *node_name = 0;
  file_t node;

  /* The translator's arg vector, in '\0' separated format.  */
  char *argz = 0;
  size_t argz_len = 0;

  /* The control port for any active translator we start up.  */
  fsys_t active_control = MACH_PORT_NULL;

  /* Flags to pass to file_set_translator.  */
  int active_flags = 0;
  int passive_flags = 0;
  int lookup_flags = O_NOTRANS;
  int goaway_flags = 0;

  /* Various option flags.  */
  int passive = 0, active = 0, keep_active = 0, pause = 0, kill_active = 0,
      orphan = 0;
  int start = 0;
  char *pid_file = NULL;
  int excl = 0;
  int timeout = DEFAULT_TIMEOUT * 1000; /* ms */
  char **chroot_command = 0;
  char *chroot_chdir = "/";

  /* Parse our options...  */
  error_t parse_opt (int key, char *arg, struct argp_state *state)
    {
      switch (key)
	{
	case ARGP_KEY_ARG:
	  if (state->arg_num == 0)
	    node_name = arg;
	  else			/* command */
	    {
	      if (start)
		argp_error (state, "both --start and TRANSLATOR given");

	      error_t err =
		argz_create (state->argv + state->next - 1, &argz, &argz_len);
	      if (err)
		error(3, err, "Can't create options vector");
	      state->next = state->argc; /* stop parsing */
	    }
	  break;

	case ARGP_KEY_NO_ARGS:
	  argp_usage (state);
	  return EINVAL;

	case 'a': active = 1; break;
	case 's':
	  start = 1;
	  active = 1;	/* start implies active */
	  break;
	case 'p': passive = 1; break;
	case 'k': keep_active = 1; break;
	case 'g': kill_active = 1; break;
	case 'x': excl = 1; break;
	case 'P': pause = 1; break;
	case 'F':
	  pid_file = strdup (arg);
	  if (pid_file == NULL)
	    error(3, ENOMEM, "Failed to duplicate argument");
	  break;

	case 'o': orphan = 1; break;

	case 'C':
	  if (chroot_command)
	    {
	      argp_error (state, "--chroot given twice");
	      return EINVAL;
	    }
	  chroot_command = &state->argv[state->next];
	  while (state->next < state->argc)
	    {
	      if (!strcmp (state->argv[state->next], "--"))
		{
		  state->argv[state->next++] = 0;
		  if (chroot_command[0] == 0)
		    {
		      argp_error (state,
				  "--chroot must be followed by a command");
		      return EINVAL;
		    }
		  return 0;
		}
	      ++state->next;
	    }
	  argp_error (state, "--chroot command must be terminated with `--'");
	  return EINVAL;

	case OPT_CHROOT_CHDIR:
	  if (arg[0] != '/')
	    argp_error (state, "--chroot-chdir must be absolute");
	  chroot_chdir = arg;
	  break;

	case 'c': lookup_flags |= O_CREAT; break;
	case 'L': lookup_flags &= ~O_NOTRANS; break;

	case 'R': goaway_flags |= FSYS_GOAWAY_RECURSE; break;
	case 'S': goaway_flags |= FSYS_GOAWAY_NOSYNC; break;
	case 'f': goaway_flags |= FSYS_GOAWAY_FORCE; break;

	  /* Use atof so the user can specifiy fractional timeouts.  */
	case 't': timeout = atof (arg) * 1000.0; break;

	default:
	  return ARGP_ERR_UNKNOWN;
	}
      return 0;
    }
  struct argp argp = {options, parse_opt, args_doc, doc};

  argp_parse (&argp, argc, argv, ARGP_IN_ORDER, 0, 0);

  if (!active && !passive && !chroot_command)
    passive = 1;		/* By default, set the passive translator.  */

  if (passive)
    passive_flags = FS_TRANS_SET | (excl ? FS_TRANS_EXCL : 0);
  if (active)
    active_flags = FS_TRANS_SET | (excl ? FS_TRANS_EXCL : 0)
		   | (orphan ? FS_TRANS_ORPHAN : 0);

  if (passive && !active)
    {
      /* When setting just the passive, decide what to do with any active.  */
      if (kill_active)
	/* Make it go away.  */
	active_flags = FS_TRANS_SET;
      else if (! keep_active)
	/* Ensure that there isn't one.  */
	active_flags = FS_TRANS_SET | FS_TRANS_EXCL;
    }

  if (start)
    {
      /* Retrieve the passive translator record in argz.  */
      mach_port_t node = file_name_lookup (node_name, lookup_flags, 0);
      if (node == MACH_PORT_NULL)
	error (4, errno, "%s", node_name);

      char buf[1024];
      argz = buf;
      argz_len = sizeof (buf);

      err = file_get_translator (node, &argz, &argz_len);
      if (err == EINVAL)
	error (4, 0, "%s: no passive translator record found", node_name);
      if (err)
	error (4, err, "%s", node_name);

      mach_port_deallocate (mach_task_self (), node);
    }

  if ((active || chroot_command) && argz_len > 0)
    {
      /* Error during file lookup; we use this to avoid duplicating error
	 messages.  */
      error_t open_err = 0;

      /* The callback to start_translator opens NODE as a side effect.  */
      error_t open_node (int flags,
			 mach_port_t *underlying,
			 mach_msg_type_name_t *underlying_type,
			 task_t task, void *cookie)
	{
	  if (pause)
	    {
	      fprintf (stderr, "Translator pid: %d\nPausing...",
	               task2pid (task));
	      getchar ();
	    }

	  if (pid_file != NULL)
	    {
	      FILE *h;
	      h = fopen (pid_file, "w");
	      if (h == NULL)
		error (4, errno, "Failed to open pid file");

	      fprintf (h, "%i\n", task2pid (task));
	      fclose (h);
	    }

	  node = file_name_lookup (node_name, flags | lookup_flags, 0666);
	  if (node == MACH_PORT_NULL)
	    {
	      open_err = errno;
	      return open_err;
	    }

	  *underlying = node;
	  *underlying_type = MACH_MSG_TYPE_COPY_SEND;

	  return 0;
	}
      err = fshelp_start_translator (open_node, NULL, argz, argz, argz_len,
				     timeout, &active_control);
      if (err)
	/* If ERR is due to a problem opening the translated node, we print
	   that name, otherwise, the name of the translator.  */
	error(4, err, "%s", (err == open_err) ? node_name : argz);
    }
  else
    {
      node = file_name_lookup(node_name, lookup_flags, 0666);
      if (node == MACH_PORT_NULL)
	error(1, errno, "%s", node_name);
    }

  if (active || passive)
    {
      err = file_set_translator (node,
				 passive_flags, active_flags, goaway_flags,
				 argz, argz_len,
				 active_control, MACH_MSG_TYPE_COPY_SEND);
      if (err)
	error (5, err, "%s", node_name);
    }

  if (chroot_command)
    {
      pid_t child;
      int status;
      switch ((child = fork ()))
	{
	case -1:
	  error (6, errno, "fork");

	case 0:; /* Child.  */
	  /* We will act as the parent filesystem would for a lookup
	     of the active translator's root node, then use this port
	     as our root directory while we exec the command.  */

	  char retry_name[1024];	/* XXX */
	  retry_type do_retry;
	  mach_port_t root;
	  file_t executable;
	  char *prefixed_name;

	  err = get_credentials ();
	  if (err)
	    error (6, err, "getting credentials");

	  err = fsys_getroot (active_control,
			      MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND,
			      uids, uids_len, gids, gids_len, 0,
			      &do_retry, retry_name, &root);
	  mach_port_deallocate (mach_task_self (), active_control);
	  if (err)
	    error (6, err, "fsys_getroot");
	  err = hurd_file_name_lookup_retry (&_hurd_ports_use, &getdport, 0,
					     do_retry, retry_name, 0, 0,
					     &root);
	  if (err)
	    error (6, err, "cannot resolve root port");

	  if (setcrdir (root))
	    error (7, errno, "cannot install root port");
	  mach_port_deallocate (mach_task_self (), root);
	  if (chdir (chroot_chdir))
	    error (8, errno, "%s", chroot_chdir);

	  /* Lookup executable in PATH.  */
	  executable = file_name_path_lookup (chroot_command[0],
					      getenv ("PATH"),
					      O_EXEC, 0,
					      &prefixed_name);
	  if (MACH_PORT_VALID (executable))
	    {
	      err = mach_port_deallocate (mach_task_self (), executable);
	      assert_perror (err);
	      if (prefixed_name)
		chroot_command[0] = prefixed_name;
	    }

	  execvp (chroot_command[0], chroot_command);
	  error (8, errno, "cannot execute %s", chroot_command[0]);
	  break;

	default: /* Parent.  */
	  if (waitpid (child, &status, 0) != child)
	    error (8, errno, "waitpid on %d", child);

	  err = fsys_goaway (active_control, goaway_flags);
	  if (err && err != EBUSY)
	    error (9, err, "fsys_goaway");

	  if (WIFSIGNALED (status))
	    error (WTERMSIG (status) + 128, 0,
		   "%s for child %d", strsignal (WTERMSIG (status)), child);
	  if (WEXITSTATUS (status) != 0)
	    error (WEXITSTATUS (status), 0,
		   "Error %d for child %d", WEXITSTATUS (status), child);
	}
    }

  return 0;
}