1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dir-watch-kqueue.c OS specific directory change notification for message bus
3 *
4 * Copyright (C) 2003 Red Hat, Inc.
5 *
6 * Licensed under the Academic Free License version 2.1
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 *
22 */
23
24 #include <config.h>
25
26 #include <sys/types.h>
27 #include <sys/event.h>
28 #include <sys/time.h>
29 #include <signal.h>
30 #include <fcntl.h>
31 #include <unistd.h>
32 #ifdef HAVE_ERRNO_H
33 #include <errno.h>
34 #endif
35
36 #include "bus.h"
37 #include <dbus/dbus-watch.h>
38
39 #include <dbus/dbus-internals.h>
40 #include <dbus/dbus-list.h>
41 #include "dir-watch.h"
42
43 #define MAX_DIRS_TO_WATCH 128
44
45 static int kq = -1;
46 static int fds[MAX_DIRS_TO_WATCH];
47 static char *dirs[MAX_DIRS_TO_WATCH];
48 static int num_fds = 0;
49 static DBusWatch *watch = NULL;
50 static DBusLoop *loop = NULL;
51
52 static dbus_bool_t
_handle_kqueue_watch(DBusWatch * watch,unsigned int flags,void * data)53 _handle_kqueue_watch (DBusWatch *watch, unsigned int flags, void *data)
54 {
55 struct kevent ev;
56 struct timespec nullts = { 0, 0 };
57 int res;
58 pid_t pid;
59
60 res = kevent (kq, NULL, 0, &ev, 1, &nullts);
61
62 /* Sleep for half a second to avoid a race when files are install(1)'d
63 * to system.d. */
64 usleep(500000);
65
66 if (res > 0)
67 {
68 pid = getpid ();
69 _dbus_verbose ("Sending SIGHUP signal on reception of a kevent\n");
70 (void) kill (pid, SIGHUP);
71 }
72 else if (res < 0 && errno == EBADF)
73 {
74 kq = -1;
75 if (watch != NULL)
76 {
77 _dbus_loop_remove_watch (loop, watch);
78 _dbus_watch_invalidate (watch);
79 _dbus_watch_unref (watch);
80 watch = NULL;
81 }
82 pid = getpid ();
83 _dbus_verbose ("Sending SIGHUP signal since kqueue has been closed\n");
84 (void) kill (pid, SIGHUP);
85 }
86
87 return TRUE;
88 }
89
90 static int
_init_kqueue(BusContext * context)91 _init_kqueue (BusContext *context)
92 {
93 int ret = 0;
94
95 if (kq < 0)
96 {
97
98 kq = kqueue ();
99 if (kq < 0)
100 {
101 _dbus_warn ("Cannot create kqueue; error '%s'\n", _dbus_strerror (errno));
102 goto out;
103 }
104
105 loop = bus_context_get_loop (context);
106
107 watch = _dbus_watch_new (kq, DBUS_WATCH_READABLE, TRUE,
108 _handle_kqueue_watch, NULL, NULL);
109
110 if (watch == NULL)
111 {
112 _dbus_warn ("Unable to create kqueue watch\n");
113 close (kq);
114 kq = -1;
115 goto out;
116 }
117
118 if (!_dbus_loop_add_watch (loop, watch))
119 {
120 _dbus_warn ("Unable to add reload watch to main loop");
121 _dbus_watch_invalidate (watch);
122 _dbus_watch_unref (watch);
123 watch = NULL;
124 close (kq);
125 kq = -1;
126 goto out;
127 }
128 }
129
130 ret = 1;
131
132 out:
133 return ret;
134 }
135
136 void
bus_set_watched_dirs(BusContext * context,DBusList ** directories)137 bus_set_watched_dirs (BusContext *context, DBusList **directories)
138 {
139 int new_fds[MAX_DIRS_TO_WATCH];
140 char *new_dirs[MAX_DIRS_TO_WATCH];
141 DBusList *link;
142 int i, j, f, fd;
143 struct kevent ev;
144
145 if (!_init_kqueue (context))
146 goto out;
147
148 for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
149 {
150 new_fds[i] = -1;
151 new_dirs[i] = NULL;
152 }
153
154 i = 0;
155 link = _dbus_list_get_first_link (directories);
156 while (link != NULL)
157 {
158 new_dirs[i++] = (char *)link->data;
159 link = _dbus_list_get_next_link (directories, link);
160 }
161
162 /* Look for directories in both the old and new sets, if
163 * we find one, move its data into the new set.
164 */
165 for (i = 0; new_dirs[i]; i++)
166 {
167 for (j = 0; j < num_fds; j++)
168 {
169 if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0)
170 {
171 new_fds[i] = fds[j];
172 new_dirs[i] = dirs[j];
173 fds[j] = -1;
174 dirs[j] = NULL;
175 break;
176 }
177 }
178 }
179
180 /* Any directory we find in "fds" with a nonzero fd must
181 * not be in the new set, so perform cleanup now.
182 */
183 for (j = 0; j < num_fds; j++)
184 {
185 if (fds[j] != -1)
186 {
187 close (fds[j]);
188 dbus_free (dirs[j]);
189 fds[j] = -1;
190 dirs[j] = NULL;
191 }
192 }
193
194 for (i = 0; new_dirs[i]; i++)
195 {
196 if (new_fds[i] == -1)
197 {
198 /* FIXME - less lame error handling for failing to add a watch;
199 * we may need to sleep.
200 */
201 fd = open (new_dirs[i], O_RDONLY);
202 if (fd < 0)
203 {
204 if (errno != ENOENT)
205 {
206 _dbus_warn ("Cannot open directory '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno));
207 goto out;
208 }
209 else
210 {
211 new_fds[i] = -1;
212 new_dirs[i] = NULL;
213 continue;
214 }
215 }
216
217 EV_SET (&ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
218 NOTE_DELETE | NOTE_EXTEND | NOTE_WRITE | NOTE_RENAME, 0, 0);
219 if (kevent (kq, &ev, 1, NULL, 0, NULL) == -1)
220 {
221 _dbus_warn ("Cannot setup a kevent for '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno));
222 close (fd);
223 goto out;
224 }
225
226 new_fds[i] = fd;
227 new_dirs[i] = _dbus_strdup (new_dirs[i]);
228 if (!new_dirs[i])
229 {
230 /* FIXME have less lame handling for OOM, we just silently fail to
231 * watch. (In reality though, the whole OOM handling in dbus is
232 * stupid but we won't go into that in this comment =) )
233 */
234 close (fd);
235 new_fds[i] = -1;
236 }
237 }
238 }
239
240 num_fds = i;
241
242 for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
243 {
244 fds[i] = new_fds[i];
245 dirs[i] = new_dirs[i];
246 }
247
248 out:
249 ;
250 }
251