summaryrefslogtreecommitdiff
path: root/bus/dir-watch-kqueue.c
blob: 183db241c03dd56a65a0515483efcb5fcb4e63b4 (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
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dir-watch-kqueue.c  OS specific directory change notification for message bus
 *
 * Copyright (C) 2003 Red Hat, Inc.
 *
 * Licensed under the Academic Free License version 2.1
 *
 * 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 of the License, 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include <config.h>

#include <sys/types.h>
#include <sys/event.h>
#include <sys/time.h>
#include <signal.h>
#include <fcntl.h>
#include <unistd.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif

#include "bus.h"
#include <dbus/dbus-watch.h>

#include <dbus/dbus-internals.h>
#include <dbus/dbus-list.h>
#include <dbus/dbus-sysdeps-unix.h>
#include "dir-watch.h"

#define MAX_DIRS_TO_WATCH 128

static int kq = -1;
static int fds[MAX_DIRS_TO_WATCH];
static char *dirs[MAX_DIRS_TO_WATCH];
static int num_fds = 0;
static DBusWatch *watch = NULL;
static DBusLoop *loop = NULL;

static dbus_bool_t
_handle_kqueue_watch (DBusWatch *watch, unsigned int flags, void *data)
{
  struct kevent ev;
  struct timespec nullts = { 0, 0 };
  int res;
  pid_t pid;

  res = kevent (kq, NULL, 0, &ev, 1, &nullts);

  /* Sleep for half a second to avoid a race when files are install(1)'d
   * to system.d. */
  usleep(500000);

  if (res > 0)
    {
      pid = getpid ();
      _dbus_verbose ("Sending SIGHUP signal on reception of a kevent\n");
      (void) kill (pid, SIGHUP);
    }
  else if (res < 0 && errno == EBADF)
    {
      kq = -1;
      if (watch != NULL)
        {
          _dbus_loop_remove_watch (loop, watch);
          _dbus_watch_invalidate (watch);
          _dbus_watch_unref (watch);
          watch = NULL;
        }
      pid = getpid ();
      _dbus_verbose ("Sending SIGHUP signal since kqueue has been closed\n");
      (void) kill (pid, SIGHUP);
    }

  return TRUE;
}

static void _shutdown_kqueue (void *data)
{
  int i;

  if (kq < 0)
    return;

  for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
    {
      if (fds[i] >= 0)
        {
          close (fds[i]);
          fds[i] = -1;
        }
      if (dirs[i] != NULL)
        {
          /* dbus_free() is necessary to pass memleak check */
          dbus_free (dirs[i]);
          dirs[i] = NULL;
        }
    }

  if (loop)
    {
      _dbus_loop_remove_watch (loop, watch);
      _dbus_loop_unref (loop);
      loop = NULL;
    }

  if (watch)
    {
      _dbus_watch_invalidate (watch);
      _dbus_watch_unref (watch);
      watch = NULL;
    }

    close (kq);
    kq = -1;
}

static int
_init_kqueue (BusContext *context)
{
  if (kq < 0)
    {

      kq = kqueue ();
      if (kq < 0)
        {
          _dbus_warn ("Cannot create kqueue; error '%s'", _dbus_strerror (errno));
          goto out;
        }

      loop = bus_context_get_loop (context);
      _dbus_loop_ref (loop);

      watch = _dbus_watch_new (kq, DBUS_WATCH_READABLE, TRUE,
                               _handle_kqueue_watch, NULL, NULL);

      if (watch == NULL)
        {
          _dbus_warn ("Unable to create kqueue watch");
          goto out1;
        }

      if (!_dbus_loop_add_watch (loop, watch))
        {
          _dbus_warn ("Unable to add reload watch to main loop");
          goto out2;
        }

      if (!_dbus_register_shutdown_func (_shutdown_kqueue, NULL))
        {
          _dbus_warn ("Unable to register shutdown function");
          goto out3;
        }
    }

  return 1;

out3:
  _dbus_loop_remove_watch (loop, watch);

out2:
  if (watch)
    {
      _dbus_watch_invalidate (watch);
      _dbus_watch_unref (watch);
      watch = NULL;
    }

out1:
  if (kq >= 0)
    {
      close (kq);
      kq = -1;
    }
  if (loop)
    {
      _dbus_loop_unref (loop);
      loop = NULL;
    }

out:
  return 0;
}

void
bus_set_watched_dirs (BusContext *context, DBusList **directories)
{
  int new_fds[MAX_DIRS_TO_WATCH];
  char *new_dirs[MAX_DIRS_TO_WATCH];
  DBusList *link;
  int i, j, fd;
  struct kevent ev;
#ifdef O_CLOEXEC
  dbus_bool_t cloexec_done = 0;
#endif

  if (!_init_kqueue (context))
    goto out;

  for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
    {
      new_fds[i] = -1;
      new_dirs[i] = NULL;
    }

  i = 0;
  link = _dbus_list_get_first_link (directories);
  while (link != NULL)
    {
      new_dirs[i++] = (char *)link->data;
      link = _dbus_list_get_next_link (directories, link);
    }

  /* Look for directories in both the old and new sets, if
   * we find one, move its data into the new set.
   */
  for (i = 0; new_dirs[i]; i++)
    {
      for (j = 0; j < num_fds; j++)
        {
          if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0)
            {
              new_fds[i] = fds[j];
              new_dirs[i] = dirs[j];
              fds[j] = -1;
              dirs[j] = NULL;
              break;
            }
        }
    }

  /* Any directory we find in "fds" with a nonzero fd must
   * not be in the new set, so perform cleanup now.
   */
  for (j = 0; j < num_fds; j++)
    {
      if (fds[j] != -1)
        {
          close (fds[j]);
          dbus_free (dirs[j]);
          fds[j] = -1;
          dirs[j] = NULL;
        }
    }

  for (i = 0; new_dirs[i]; i++)
    {
      if (new_fds[i] == -1)
        {
          /* FIXME - less lame error handling for failing to add a watch;
           * we may need to sleep.
           */
#ifdef O_CLOEXEC
          fd = open (new_dirs[i], O_RDONLY | O_CLOEXEC);
          cloexec_done = (fd >= 0);

          if (fd < 0 && errno == EINVAL)
#endif
            {
              fd = open (new_dirs[i], O_RDONLY);
            }
          if (fd < 0)
            {
              if (errno != ENOENT)
                {
                  _dbus_warn ("Cannot open directory '%s'; error '%s'", new_dirs[i], _dbus_strerror (errno));
                  goto out;
                }
              else
                {
                  new_fds[i] = -1;
                  new_dirs[i] = NULL;
                  continue;
                }
            }
#ifdef O_CLOEXEC
          if (!cloexec_done)
#endif
            {
              _dbus_fd_set_close_on_exec (fd);
            }

          EV_SET (&ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
                  NOTE_DELETE | NOTE_EXTEND | NOTE_WRITE | NOTE_RENAME, 0, 0);
          if (kevent (kq, &ev, 1, NULL, 0, NULL) == -1)
            {
              _dbus_warn ("Cannot setup a kevent for '%s'; error '%s'", new_dirs[i], _dbus_strerror (errno));
              close (fd);
              goto out;
            }

          new_fds[i] = fd;
          new_dirs[i] = _dbus_strdup (new_dirs[i]);
          if (!new_dirs[i])
            {
              /* FIXME have less lame handling for OOM, we just silently fail to
               * watch.  (In reality though, the whole OOM handling in dbus is
               * stupid but we won't go into that in this comment =) )
               */
              close (fd);
              new_fds[i] = -1;
            }
        }
    }

  num_fds = i;

  for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
    {
      fds[i] = new_fds[i];
      dirs[i] = new_dirs[i];
    }

 out:
  ;
}