2 * udevd.c - hotplug event serializer
4 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
5 * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation version 2 of the License.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 675 Mass Ave, Cambridge, MA 02139, USA.
32 #include <sys/types.h>
33 #include <sys/socket.h>
39 #include "udev_version.h"
43 static int expected_seqnum = 0;
44 volatile static int children_waiting;
45 volatile static int msg_q_timeout;
49 LIST_HEAD(running_list);
51 static void exec_queue_manager(void);
52 static void msg_queue_manager(void);
54 unsigned char logname[42];
61 static void msg_dump_queue(void)
63 struct hotplug_msg *msg;
65 list_for_each_entry(msg, &msg_list, list)
66 dbg("sequence %d in queue", msg->seqnum);
69 static void msg_dump(struct hotplug_msg *msg)
71 dbg("sequence %d, '%s', '%s', '%s'",
72 msg->seqnum, msg->action, msg->devpath, msg->subsystem);
75 static struct hotplug_msg *msg_create(void)
77 struct hotplug_msg *new_msg;
79 new_msg = malloc(sizeof(struct hotplug_msg));
85 static void run_queue_delete(struct hotplug_msg *msg)
92 /* orders the message in the queue by sequence number */
93 static void msg_queue_insert(struct hotplug_msg *msg)
95 struct hotplug_msg *loop_msg;
97 /* sort message by sequence number into list*/
98 list_for_each_entry(loop_msg, &msg_list, list)
99 if (loop_msg->seqnum > msg->seqnum)
101 list_add_tail(&msg->list, &loop_msg->list);
102 dbg("queued message seq %d", msg->seqnum);
104 /* store timestamp of queuing */
105 msg->queue_time = time(NULL);
107 /* run msg queue manager */
113 /* forks event and removes event from run queue when finished */
114 static void udev_run(struct hotplug_msg *msg)
117 setenv("ACTION", msg->action, 1);
118 setenv("DEVPATH", msg->devpath, 1);
124 execl(UDEV_BIN, "udev", msg->subsystem, NULL);
125 dbg("exec of child failed");
129 dbg("fork of child failed");
130 run_queue_delete(msg);
133 /* get SIGCHLD in main loop */
134 dbg("==> exec seq %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
139 /* returns already running task with devpath */
140 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
142 struct hotplug_msg *loop_msg;
143 list_for_each_entry(loop_msg, &running_list, list)
144 if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0)
149 /* exec queue management routine executes the events and delays events for the same devpath */
150 static void exec_queue_manager()
152 struct hotplug_msg *loop_msg;
153 struct hotplug_msg *tmp_msg;
154 struct hotplug_msg *msg;
156 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
157 msg = running_with_devpath(loop_msg);
159 /* move event to run list */
160 list_move_tail(&loop_msg->list, &running_list);
162 dbg("moved seq %d to running list", loop_msg->seqnum);
164 dbg("delay seq %d, cause seq %d already working on '%s'",
165 loop_msg->seqnum, msg->seqnum, msg->devpath);
170 static void msg_move_exec(struct hotplug_msg *msg)
172 list_move_tail(&msg->list, &exec_list);
173 exec_queue_manager();
174 expected_seqnum = msg->seqnum+1;
175 dbg("moved seq %d to exec, next expected is %d",
176 msg->seqnum, expected_seqnum);
179 /* msg queue management routine handles the timeouts and dispatches the events */
180 static void msg_queue_manager()
182 struct hotplug_msg *loop_msg;
183 struct hotplug_msg *tmp_msg;
186 dbg("msg queue manager, next expected is %d", expected_seqnum);
188 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
189 /* move event with expected sequence to the exec list */
190 if (loop_msg->seqnum == expected_seqnum) {
191 msg_move_exec(loop_msg);
195 /* move event with expired timeout to the exec list */
196 msg_age = time(NULL) - loop_msg->queue_time;
197 if (msg_age > EVENT_TIMEOUT_SEC-1) {
198 msg_move_exec(loop_msg);
207 if (list_empty(&msg_list) == 0) {
208 /* set timeout for remaining queued events */
209 struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}};
210 dbg("next event expires in %li seconds",
211 EVENT_TIMEOUT_SEC - msg_age);
212 setitimer(ITIMER_REAL, &itv, 0);
216 /* receive the msg, do some basic sanity checks, and queue it */
217 static void handle_msg(int sock)
219 struct hotplug_msg *msg;
224 dbg("unable to store message");
228 retval = recv(sock, msg, sizeof(struct hotplug_msg), 0);
231 dbg("unable to receive message");
235 if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
236 dbg("message magic '%s' doesn't match, ignore it", msg->magic);
241 /* if no seqnum is given, we move straight to exec queue */
242 if (msg->seqnum == -1) {
243 list_add(&msg->list, &exec_list);
244 exec_queue_manager();
246 msg_queue_insert(msg);
250 static void sig_handler(int signum)
261 children_waiting = 1;
264 dbg("unhandled signal");
268 static void udev_done(int pid)
270 /* find msg associated with pid and delete it */
271 struct hotplug_msg *msg;
273 list_for_each_entry(msg, &running_list, list) {
274 if (msg->pid == pid) {
275 dbg("<== exec seq %d came back", msg->seqnum);
276 run_queue_delete(msg);
282 int main(int argc, char *argv[])
285 struct sockaddr_un saddr;
289 init_logging("udevd");
291 signal(SIGINT, sig_handler);
292 signal(SIGTERM, sig_handler);
293 signal(SIGALRM, sig_handler);
294 signal(SIGCHLD, sig_handler);
296 /* we want these two to interrupt system calls */
297 siginterrupt(SIGALRM, 1);
298 siginterrupt(SIGCHLD, 1);
300 memset(&saddr, 0x00, sizeof(saddr));
301 saddr.sun_family = AF_LOCAL;
302 /* use abstract namespace for socket path */
303 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
304 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
306 ssock = socket(AF_LOCAL, SOCK_DGRAM, 0);
308 dbg("error getting socket");
312 /* the bind takes care of ensuring only one copy running */
313 retval = bind(ssock, &saddr, addrlen);
315 dbg("bind failed\n");
322 while(msg_q_timeout) {
327 while(children_waiting) {
328 children_waiting = 0;
329 /* reap all dead children */
331 int pid = waitpid(-1, 0, WNOHANG);
332 if ((pid == -1) || (pid == 0))