summaryrefslogtreecommitdiff
path: root/login/utmp_daemon.c
blob: 1cf899f2a627a522cacd51372366a3dca787653f (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
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
/* Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 1997.

   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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <utmp.h>

#include "utmp-private.h"
#include "programs/utmpd.h"


/* Descriptor for the socket.  */
static int daemon_sock = -1;


/* Functions defined here.  */
static int setutent_daemon (void);
static int getutent_r_daemon (struct utmp *buffer, struct utmp **result);
static int getutid_r_daemon (const struct utmp *line, struct utmp *buffer,
			     struct utmp **result);
static int getutline_r_daemon (const struct utmp *id, struct utmp *buffer,
			       struct utmp **result);
static struct utmp *pututline_daemon (const struct utmp *utmp);
static void endutent_daemon (void);
static int updwtmp_daemon (const char *file, const struct utmp *utmp);

/* Jump table for daemon functions.  */
struct utfuncs __libc_utmp_daemon_functions =
{
  setutent_daemon,
  getutent_r_daemon,
  getutid_r_daemon,
  getutline_r_daemon,
  pututline_daemon,
  endutent_daemon,
  updwtmp_daemon
};

static int do_setutent (int sock);
static int do_getutent (int sock, struct utmp *buffer);
static int do_getutid (int sock, const struct utmp *id,
			    struct utmp *buffer);
static int do_pututline (int sock, const struct utmp *utmp);
static int do_getutline (int sock, const struct utmp *line,
			 struct utmp *buffer);
static int do_pututline (int sock, const struct utmp *utmp);
static int do_endutent (int sock);
static int do_updwtmp (int sock, const char *file,
		       const struct utmp *utmp);

static int open_socket (const char *name);
static int send_request (int sock, const request_header *request,
			 reply_header *reply);


static int
setutent_daemon (void)
{
  if (__access (_PATH_UTMPD_RW, F_OK) == -1
      && __access (_PATH_UTMPD_RO, F_OK) == -1)
    return 0;

  if (daemon_sock < 0)
    {
      int result;

      daemon_sock = open_socket (_PATH_UTMPD_RW);
      if (daemon_sock < 0)
	{
	  /* Hhm, read-write access did not work.  Try read-only.  */
	  daemon_sock = open_socket (_PATH_UTMPD_RO);
	  if (daemon_sock < 0)
	    return 0;
	}

      /* We have to make sure the socket is `closed on exec'.  */
      result = __fcntl (daemon_sock, F_GETFD, 0);
      if (result >= 0)
	result = __fcntl (daemon_sock, F_SETFD, result | FD_CLOEXEC);
      if (result == -1)
	{
	  close (daemon_sock);
	  return 0;
	}
    }

  /* Send request to the daemon.  */
  if (do_setutent (daemon_sock) < 0)
    return 0;

  return 1;
}


static int
getutent_r_daemon (struct utmp *buffer, struct utmp **result)
{
  assert (daemon_sock >= 0);

  /* Send request to the daemon.  */
  if (do_getutent (daemon_sock, buffer) < 0)
    {
      *result = NULL;
      return -1;;
    }

  *result = buffer;
  return 0;
}


static int
getutid_r_daemon (const struct utmp *id, struct utmp *buffer,
		  struct utmp **result)
{
  assert (daemon_sock >= 0);

  /* Send request to the daemon.  */
  if (do_getutid (daemon_sock, id, buffer) < 0)
    {
      *result = NULL;
      return -1;
    }

  *result = buffer;
  return 0;
}


static int
getutline_r_daemon (const struct utmp *line, struct utmp *buffer,
		    struct utmp **result)
{
  assert (daemon_sock >= 0);

  /* Send request to the daemon.  */
  if (do_getutline (daemon_sock, line, buffer) < 0)
    {
      *result = NULL;
      return -1;
    }

  *result = buffer;
  return 0;
}


static struct utmp *
pututline_daemon (const struct utmp *utmp)
{
  assert (daemon_sock >= 0);

  /* Send request to the daemon.  */
  if (do_pututline (daemon_sock, utmp) < 0)
    return NULL;

  return (struct utmp *)utmp;
}


static void
endutent_daemon (void)
{
  assert (daemon_sock >= 0);

  /* Send request to the daemon.  */
  do_endutent (daemon_sock);

  __close (daemon_sock);
  daemon_sock = -1;
}


static int
updwtmp_daemon (const char *file, const struct utmp *utmp)
{
  int sock;

  /* Only try to open for both reading and writing.  */
  sock = open_socket (_PATH_UTMPD_RW);
  if (sock < 0)
    return -1;

  /* Send request to the daemon.  */
  if (do_updwtmp (sock, file, utmp) < 0)
    {
      __close (sock);
      return -1;
    }

  __close (sock);
  return 0;
}


static int
do_setutent (int sock)
{
  setutent_request *request;
  setutent_reply reply;
  size_t size;
  size_t name_len;

  name_len = strlen (__libc_utmp_file_name) + 1;
  size = sizeof (setutent_request) + name_len;

  request = malloc (size);
  if (request == NULL)
    return -1;

  request->header.version = UTMPD_VERSION;
  request->header.size = size;
  request->header.type = UTMPD_REQ_SETUTENT;
  memcpy (request->file, __libc_utmp_file_name, name_len);

  reply.header.version = UTMPD_VERSION;
  reply.header.size = sizeof (setutent_reply);
  reply.header.type = UTMPD_REQ_SETUTENT;

  if (send_request (sock, &request->header, &reply.header) < 0)
    {
      free (request);
      return -1;
    }

  if (reply.result < 0)
    __set_errno (reply.errnum);

  free (request);
  return reply.result;
}

static int
do_getutent (int sock, struct utmp *buffer)
{
  getutent_request request;
  getutent_reply reply;

  request.header.version = UTMPD_VERSION;
  request.header.size = sizeof (getutent_request);
  request.header.type = UTMPD_REQ_GETUTENT;

  reply.header.version = UTMPD_VERSION;
  reply.header.size = sizeof (getutent_reply);
  reply.header.type = UTMPD_REQ_GETUTENT;

  if (send_request (sock, &request.header, &reply.header) < 0)
    return -1;

  if (reply.result < 0)
    __set_errno (reply.errnum);
  else
    memcpy (buffer, &reply.entry, sizeof (struct utmp));

  return reply.result;
}

static int
do_getutid (int sock, const struct utmp *id, struct utmp *buffer)
{
  getutid_request request;
  getutid_reply reply;

  request.header.version = UTMPD_VERSION;
  request.header.size = sizeof (getutid_request);
  request.header.type = UTMPD_REQ_GETUTID;
  memcpy (&request.id, id, sizeof (struct utmp));

  reply.header.version = UTMPD_VERSION;
  reply.header.size = sizeof (getutid_reply);
  reply.header.type = UTMPD_REQ_GETUTID;

  if (send_request (sock, &request.header, &reply.header) < 0)
    return -1;

  if (reply.result < 0)
    __set_errno (reply.errnum);
  else
    memcpy (buffer, &reply.entry, sizeof (struct utmp));

  return reply.result;
}

static int
do_getutline (int sock, const struct utmp *line, struct utmp *buffer)
{
  getutline_request request;
  getutline_reply reply;

  request.header.version = UTMPD_VERSION;
  request.header.size = sizeof (getutline_request);
  request.header.type = UTMPD_REQ_GETUTLINE;
  memcpy (&request.line, line, sizeof (struct utmp));

  reply.header.version = UTMPD_VERSION;
  reply.header.size = sizeof (getutline_reply);
  reply.header.type = UTMPD_REQ_GETUTLINE;

  if (send_request (sock, &request.header, &reply.header) < 0)
    return -1;

  if (reply.result < 0)
    __set_errno (reply.errnum);
  else
    memcpy (buffer, &reply.entry, sizeof (struct utmp));

  return reply.result;
}

static int
do_pututline (int sock, const struct utmp *utmp)
{
  pututline_request request;
  pututline_reply reply;

  request.header.version = UTMPD_VERSION;
  request.header.size = sizeof (pututline_request);
  request.header.type = UTMPD_REQ_PUTUTLINE;
  memcpy (&request.utmp, utmp, sizeof (struct utmp));

  reply.header.version = UTMPD_VERSION;
  reply.header.size = sizeof (pututline_reply);
  reply.header.type = UTMPD_REQ_PUTUTLINE;

  if (send_request (sock, &request.header, &reply.header) < 0)
    return -1;

  if (reply.result < 0)
    __set_errno (reply.errnum);

  return reply.result;
}

static int
do_endutent (int sock)
{
  endutent_request request;
  endutent_reply reply;

  request.header.version = UTMPD_VERSION;
  request.header.size = sizeof (endutent_request);
  request.header.type = UTMPD_REQ_ENDUTENT;

  reply.header.version = UTMPD_VERSION;
  reply.header.size = sizeof (endutent_reply);
  reply.header.type = UTMPD_REQ_ENDUTENT;

  if (send_request (sock, &request.header, &reply.header) < 0)
    return -1;

  if (reply.result < 0)
    __set_errno (reply.errnum);

  return reply.result;
}

static int
do_updwtmp (int sock, const char *file, const struct utmp *utmp)
{
  updwtmp_request *request;
  updwtmp_reply reply;
  size_t size;
  size_t file_len;

  file_len = strlen (file) + 1;
  size = sizeof (updwtmp_request) + file_len;

  request = malloc (size);
  if (request == NULL)
    return -1;

  request->header.version = UTMPD_VERSION;
  request->header.size = size;
  request->header.type = UTMPD_REQ_UPDWTMP;
  memcpy (&request->utmp, utmp, sizeof (struct utmp));
  memcpy (request->file, file, file_len);

  reply.header.version = UTMPD_VERSION;
  reply.header.size = sizeof (updwtmp_reply);
  reply.header.type = UTMPD_REQ_UPDWTMP;

  if (send_request (sock, &request->header, &reply.header) < 0)
    {
      free (request);
      return -1;
    }

  if (reply.result < 0)
    __set_errno (reply.errnum);

  free (request);
  return reply.result;
}


/* Create a socket connected to NAME.  */
static int
open_socket (const char *name)
{
  struct sockaddr_un addr;
  int sock;

  sock = __socket (PF_UNIX, SOCK_STREAM, 0);
  if (sock < 0)
    return -1;

  addr.sun_family = AF_UNIX;
  strcpy (addr.sun_path, name);
  if (__connect (sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
    {
      __close (sock);
      return -1;
    }

  return sock;
}

/* Send REQUEST to SOCK, and wait for reply.  Returns 0 if successful,
   storing the reply in REPLY, and -1 if not.  */
static int
send_request (int sock, const request_header *request,
	      reply_header *reply)
{
  reply_header header;
  ssize_t nbytes;

  nbytes = __write (sock, request, request->size);
  if (nbytes != (ssize_t) request->size)
    return -1;

  nbytes = __read (sock, &header, sizeof (reply_header));
  if (nbytes != sizeof (reply_header))
    return -1;

  if (reply->version != header.version
      || reply->size != header.size
      || reply->type != header.type)
    return -1;

  nbytes = __read (sock, reply + 1, reply->size - sizeof (reply_header));
  if (nbytes != (ssize_t) (reply->size - sizeof (reply_header)))
    return -1;

  return 0;
}