2 * udevd.c - hotplug event serializer
4 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation version 2 of the License.
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
16 * You should have received a copy of the GNU General Public License along
17 * with this program; if not, write to the Free Software Foundation, Inc.,
18 * 675 Mass Ave, Cambridge, MA 02139, USA.
24 #include <sys/types.h>
34 #include <sys/types.h>
35 #include <sys/socket.h>
40 #include "udev_version.h"
45 static pthread_mutex_t msg_lock;
46 static pthread_mutex_t msg_active_lock;
47 static pthread_cond_t msg_active;
48 static pthread_mutex_t exec_lock;
49 static pthread_mutex_t exec_active_lock;
50 static pthread_cond_t exec_active;
51 static pthread_mutex_t running_lock;
52 static pthread_attr_t thr_attr;
53 static int expected_seqnum = 0;
57 LIST_HEAD(running_list);
60 static void msg_dump_queue(void)
62 struct hotplug_msg *msg;
64 list_for_each_entry(msg, &msg_list, list)
65 dbg("sequence %d in queue", msg->seqnum);
68 static void msg_dump(struct hotplug_msg *msg)
70 dbg("sequence %d, '%s', '%s', '%s'",
71 msg->seqnum, msg->action, msg->devpath, msg->subsystem);
74 static struct hotplug_msg *msg_create(void)
76 struct hotplug_msg *new_msg;
78 new_msg = malloc(sizeof(struct hotplug_msg));
79 if (new_msg == NULL) {
86 static void msg_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 /* signal queue activity to manager */
108 pthread_mutex_lock(&msg_active_lock);
109 pthread_cond_signal(&msg_active);
110 pthread_mutex_unlock(&msg_active_lock);
115 /* forks event and removes event from run queue when finished */
116 static void *run_threads(void * parm)
119 struct hotplug_msg *msg;
122 setenv("ACTION", msg->action, 1);
123 setenv("DEVPATH", msg->devpath, 1);
129 execl(UDEV_BIN, "udev", msg->subsystem, NULL);
130 dbg("exec of child failed");
134 dbg("fork of child failed");
137 /* wait for exit of child */
138 dbg("==> exec seq %d [%d] working at '%s'",
139 msg->seqnum, pid, msg->devpath);
141 dbg("<== exec seq %d came back", msg->seqnum);
145 /* remove event from run list */
146 pthread_mutex_lock(&running_lock);
147 list_del_init(&msg->list);
148 pthread_mutex_unlock(&running_lock);
152 /* signal queue activity to exec manager */
153 pthread_mutex_lock(&exec_active_lock);
154 pthread_cond_signal(&exec_active);
155 pthread_mutex_unlock(&exec_active_lock);
160 /* returns already running task with devpath */
161 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
163 struct hotplug_msg *loop_msg;
164 struct hotplug_msg *tmp_msg;
166 list_for_each_entry_safe(loop_msg, tmp_msg, &running_list, list)
167 if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0)
172 /* queue management executes the events and delays events for the same devpath */
173 static void *exec_queue_manager(void * parm)
175 struct hotplug_msg *loop_msg;
176 struct hotplug_msg *tmp_msg;
177 struct hotplug_msg *msg;
181 pthread_mutex_lock(&exec_lock);
182 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
183 msg = running_with_devpath(loop_msg);
185 /* move event to run list */
186 pthread_mutex_lock(&running_lock);
187 list_move_tail(&loop_msg->list, &running_list);
188 pthread_mutex_unlock(&running_lock);
190 pthread_create(&run_tid, &thr_attr, run_threads, (void *) loop_msg);
192 dbg("moved seq %d to running list", loop_msg->seqnum);
194 dbg("delay seq %d, cause seq %d already working on '%s'",
195 loop_msg->seqnum, msg->seqnum, msg->devpath);
198 pthread_mutex_unlock(&exec_lock);
200 /* wait for activation, new events or childs coming back */
201 pthread_mutex_lock(&exec_active_lock);
202 pthread_cond_wait(&exec_active, &exec_active_lock);
203 pthread_mutex_unlock(&exec_active_lock);
207 /* move message from incoming to exec queue */
208 static void msg_move_exec(struct list_head *head)
210 list_move_tail(head, &exec_list);
211 /* signal queue activity to manager */
212 pthread_mutex_lock(&exec_active_lock);
213 pthread_cond_signal(&exec_active);
214 pthread_mutex_unlock(&exec_active_lock);
217 /* queue management thread handles the timeouts and dispatches the events */
218 static void *msg_queue_manager(void * parm)
220 struct hotplug_msg *loop_msg;
221 struct hotplug_msg *tmp_msg;
226 dbg("msg queue manager, next expected is %d", expected_seqnum);
227 pthread_mutex_lock(&msg_lock);
228 pthread_mutex_lock(&exec_lock);
230 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
231 /* move event with expected sequence to the exec list */
232 if (loop_msg->seqnum == expected_seqnum) {
233 msg_move_exec(&loop_msg->list);
235 dbg("moved seq %d to exec, next expected is %d",
236 loop_msg->seqnum, expected_seqnum);
240 /* move event with expired timeout to the exec list */
241 msg_age = time(NULL) - loop_msg->queue_time;
242 if (msg_age > EVENT_TIMEOUT_SEC-1) {
243 msg_move_exec(&loop_msg->list);
244 expected_seqnum = loop_msg->seqnum+1;
245 dbg("moved seq %d to exec, reset next expected to %d",
246 loop_msg->seqnum, expected_seqnum);
254 pthread_mutex_unlock(&exec_lock);
255 pthread_mutex_unlock(&msg_lock);
257 /* wait until queue gets active or next message timeout expires */
258 pthread_mutex_lock(&msg_active_lock);
260 if (list_empty(&msg_list) == 0) {
261 tv.tv_sec = time(NULL) + EVENT_TIMEOUT_SEC - msg_age;
263 dbg("next event expires in %li seconds",
264 EVENT_TIMEOUT_SEC - msg_age);
265 pthread_cond_timedwait(&msg_active, &msg_active_lock, &tv);
267 pthread_cond_wait(&msg_active, &msg_active_lock);
269 pthread_mutex_unlock(&msg_active_lock);
273 /* every connect creates a thread which gets the msg, queues it and exits */
274 static void *client_threads(void * parm)
277 struct hotplug_msg *msg;
284 dbg("unable to store message");
288 retval = recv(sock, msg, sizeof(struct hotplug_msg), 0);
290 dbg("unable to receive message");
294 if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
295 dbg("message magic '%s' doesn't match, ignore it", msg->magic);
300 pthread_mutex_lock(&msg_lock);
301 msg_queue_insert(msg);
302 pthread_mutex_unlock(&msg_lock);
309 static void sig_handler(int signum)
319 dbg("unhandled signal");
323 static int one_and_only(void)
328 lock_file = open(UDEVD_LOCK, O_RDWR | O_CREAT, 0x640);
332 /* see if we can lock */
333 if (lockf(lock_file, F_TLOCK, 0) < 0) {
334 dbg("file is already locked, exit");
339 snprintf(string, sizeof(string), "%d\n", getpid());
340 write(lock_file, string, strlen(string));
345 int main(int argc, char *argv[])
349 struct sockaddr_un saddr;
350 struct sockaddr_un caddr;
353 pthread_t mgr_msg_tid;
354 pthread_t mgr_exec_tid;
357 /* only let one version of the daemon run at any one time */
358 if (one_and_only() != 0)
361 signal(SIGINT, sig_handler);
362 signal(SIGTERM, sig_handler);
364 memset(&saddr, 0x00, sizeof(saddr));
365 saddr.sun_family = AF_LOCAL;
366 strcpy(saddr.sun_path, UDEVD_SOCK);
369 ssock = socket(AF_LOCAL, SOCK_STREAM, 0);
371 dbg("error getting socket");
375 retval = bind(ssock, &saddr, sizeof(saddr));
377 dbg("bind failed\n");
381 retval = listen(ssock, SOMAXCONN);
383 dbg("listen failed\n");
387 pthread_mutex_init(&msg_lock, NULL);
388 pthread_mutex_init(&msg_active_lock, NULL);
389 pthread_mutex_init(&exec_lock, NULL);
390 pthread_mutex_init(&exec_active_lock, NULL);
391 pthread_mutex_init(&running_lock, NULL);
393 /* set default attributes for created threads */
394 pthread_attr_init(&thr_attr);
395 pthread_attr_setdetachstate(&thr_attr, PTHREAD_CREATE_DETACHED);
396 pthread_attr_setstacksize(&thr_attr, 16 * 1024);
398 /* init queue management */
399 pthread_create(&mgr_msg_tid, &thr_attr, msg_queue_manager, NULL);
400 pthread_create(&mgr_exec_tid, &thr_attr, exec_queue_manager, NULL);
402 clen = sizeof(caddr);
405 csock = accept(ssock, &caddr, &clen);
407 dbg("client accept failed\n");
410 pthread_create(&cli_tid, &thr_attr, client_threads, (void *) csock);