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 53 _kqueue_watch_callback (DBusWatch *watch, unsigned int condition, void *data) 54 { 55 return dbus_watch_handle (watch, condition); 56 } 57 58 static dbus_bool_t 59 _handle_kqueue_watch (DBusWatch *watch, unsigned int flags, void *data) 60 { 61 struct kevent ev; 62 struct timespec nullts = { 0, 0 }; 63 int res; 64 pid_t pid; 65 66 res = kevent (kq, NULL, 0, &ev, 1, &nullts); 67 68 /* Sleep for half a second to avoid a race when files are install(1)'d 69 * to system.d. */ 70 usleep(500000); 71 72 if (res > 0) 73 { 74 pid = getpid (); 75 _dbus_verbose ("Sending SIGHUP signal on reception of a kevent\n"); 76 (void) kill (pid, SIGHUP); 77 } 78 else if (res < 0 && errno == EBADF) 79 { 80 kq = -1; 81 if (watch != NULL) 82 { 83 _dbus_loop_remove_watch (loop, watch, _kqueue_watch_callback, NULL); 84 _dbus_watch_unref (watch); 85 watch = NULL; 86 } 87 pid = getpid (); 88 _dbus_verbose ("Sending SIGHUP signal since kqueue has been closed\n"); 89 (void) kill (pid, SIGHUP); 90 } 91 92 return TRUE; 93 } 94 95 static int 96 _init_kqueue (BusContext *context) 97 { 98 int ret = 0; 99 100 if (kq < 0) 101 { 102 103 kq = kqueue (); 104 if (kq < 0) 105 { 106 _dbus_warn ("Cannot create kqueue; error '%s'\n", _dbus_strerror (errno)); 107 goto out; 108 } 109 110 loop = bus_context_get_loop (context); 111 112 watch = _dbus_watch_new (kq, DBUS_WATCH_READABLE, TRUE, 113 _handle_kqueue_watch, NULL, NULL); 114 115 if (watch == NULL) 116 { 117 _dbus_warn ("Unable to create kqueue watch\n"); 118 close (kq); 119 kq = -1; 120 goto out; 121 } 122 123 if (!_dbus_loop_add_watch (loop, watch, _kqueue_watch_callback, 124 NULL, NULL)) 125 { 126 _dbus_warn ("Unable to add reload watch to main loop"); 127 close (kq); 128 kq = -1; 129 _dbus_watch_unref (watch); 130 watch = NULL; 131 goto out; 132 } 133 } 134 135 ret = 1; 136 137 out: 138 return ret; 139 } 140 141 void 142 bus_set_watched_dirs (BusContext *context, DBusList **directories) 143 { 144 int new_fds[MAX_DIRS_TO_WATCH]; 145 char *new_dirs[MAX_DIRS_TO_WATCH]; 146 DBusList *link; 147 int i, j, f, fd; 148 struct kevent ev; 149 150 if (!_init_kqueue (context)) 151 goto out; 152 153 for (i = 0; i < MAX_DIRS_TO_WATCH; i++) 154 { 155 new_fds[i] = -1; 156 new_dirs[i] = NULL; 157 } 158 159 i = 0; 160 link = _dbus_list_get_first_link (directories); 161 while (link != NULL) 162 { 163 new_dirs[i++] = (char *)link->data; 164 link = _dbus_list_get_next_link (directories, link); 165 } 166 167 /* Look for directories in both the old and new sets, if 168 * we find one, move its data into the new set. 169 */ 170 for (i = 0; new_dirs[i]; i++) 171 { 172 for (j = 0; j < num_fds; j++) 173 { 174 if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0) 175 { 176 new_fds[i] = fds[j]; 177 new_dirs[i] = dirs[j]; 178 fds[j] = -1; 179 dirs[j] = NULL; 180 break; 181 } 182 } 183 } 184 185 /* Any directory we find in "fds" with a nonzero fd must 186 * not be in the new set, so perform cleanup now. 187 */ 188 for (j = 0; j < num_fds; j++) 189 { 190 if (fds[j] != -1) 191 { 192 close (fds[j]); 193 dbus_free (dirs[j]); 194 fds[j] = -1; 195 dirs[j] = NULL; 196 } 197 } 198 199 for (i = 0; new_dirs[i]; i++) 200 { 201 if (new_fds[i] == -1) 202 { 203 /* FIXME - less lame error handling for failing to add a watch; 204 * we may need to sleep. 205 */ 206 fd = open (new_dirs[i], O_RDONLY); 207 if (fd < 0) 208 { 209 if (errno != ENOENT) 210 { 211 _dbus_warn ("Cannot open directory '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno)); 212 goto out; 213 } 214 else 215 { 216 new_fds[i] = -1; 217 new_dirs[i] = NULL; 218 continue; 219 } 220 } 221 222 EV_SET (&ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR, 223 NOTE_DELETE | NOTE_EXTEND | NOTE_WRITE | NOTE_RENAME, 0, 0); 224 if (kevent (kq, &ev, 1, NULL, 0, NULL) == -1) 225 { 226 _dbus_warn ("Cannot setup a kevent for '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno)); 227 close (fd); 228 goto out; 229 } 230 231 new_fds[i] = fd; 232 new_dirs[i] = _dbus_strdup (new_dirs[i]); 233 if (!new_dirs[i]) 234 { 235 /* FIXME have less lame handling for OOM, we just silently fail to 236 * watch. (In reality though, the whole OOM handling in dbus is 237 * stupid but we won't go into that in this comment =) ) 238 */ 239 close (fd); 240 new_fds[i] = -1; 241 } 242 } 243 } 244 245 num_fds = i; 246 247 for (i = 0; i < MAX_DIRS_TO_WATCH; i++) 248 { 249 fds[i] = new_fds[i]; 250 dirs[i] = new_dirs[i]; 251 } 252 253 out: 254 ; 255 } 256
