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);
55 unsigned char logname[42];
56 void log_message (int level, const char *format, ...)
60 va_start(args, format);
61 vsyslog(level, format, args);
66 static void msg_dump_queue(void)
68 struct hotplug_msg *msg;
70 list_for_each_entry(msg, &msg_list, list)
71 dbg("sequence %d in queue", msg->seqnum);
74 static void msg_dump(struct hotplug_msg *msg)
76 dbg("sequence %d, '%s', '%s', '%s'",
77 msg->seqnum, msg->action, msg->devpath, msg->subsystem);
80 static struct hotplug_msg *msg_create(void)
82 struct hotplug_msg *new_msg;
84 new_msg = malloc(sizeof(struct hotplug_msg));
90 static void run_queue_delete(struct hotplug_msg *msg)
97 /* orders the message in the queue by sequence number */
98 static void msg_queue_insert(struct hotplug_msg *msg)
100 struct hotplug_msg *loop_msg;
102 /* sort message by sequence number into list*/
103 list_for_each_entry(loop_msg, &msg_list, list)
104 if (loop_msg->seqnum > msg->seqnum)
106 list_add_tail(&msg->list, &loop_msg->list);
107 dbg("queued message seq %d", msg->seqnum);
109 /* store timestamp of queuing */
110 msg->queue_time = time(NULL);
112 /* run msg queue manager */
118 /* forks event and removes event from run queue when finished */
119 static void udev_run(struct hotplug_msg *msg)
124 char *env[] = { action, devpath, NULL };
126 snprintf(action, sizeof(action), "ACTION=%s", msg->action);
127 snprintf(devpath, sizeof(devpath), "DEVPATH=%s", msg->devpath);
133 execle(UDEV_BIN, "udev", msg->subsystem, NULL, env);
134 dbg("exec of child failed");
138 dbg("fork of child failed");
139 run_queue_delete(msg);
142 /* get SIGCHLD in main loop */
143 dbg("==> exec seq %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
148 /* returns already running task with devpath */
149 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
151 struct hotplug_msg *loop_msg;
152 list_for_each_entry(loop_msg, &running_list, list)
153 if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0)
158 /* exec queue management routine executes the events and delays events for the same devpath */
159 static void exec_queue_manager()
161 struct hotplug_msg *loop_msg;
162 struct hotplug_msg *tmp_msg;
163 struct hotplug_msg *msg;
165 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
166 msg = running_with_devpath(loop_msg);
168 /* move event to run list */
169 list_move_tail(&loop_msg->list, &running_list);
171 dbg("moved seq %d to running list", loop_msg->seqnum);
173 dbg("delay seq %d, cause seq %d already working on '%s'",
174 loop_msg->seqnum, msg->seqnum, msg->devpath);
179 static void msg_move_exec(struct hotplug_msg *msg)
181 list_move_tail(&msg->list, &exec_list);
182 exec_queue_manager();
183 expected_seqnum = msg->seqnum+1;
184 dbg("moved seq %d to exec, next expected is %d",
185 msg->seqnum, expected_seqnum);
188 /* msg queue management routine handles the timeouts and dispatches the events */
189 static void msg_queue_manager()
191 struct hotplug_msg *loop_msg;
192 struct hotplug_msg *tmp_msg;
195 dbg("msg queue manager, next expected is %d", expected_seqnum);
197 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
198 /* move event with expected sequence to the exec list */
199 if (loop_msg->seqnum == expected_seqnum) {
200 msg_move_exec(loop_msg);
204 /* move event with expired timeout to the exec list */
205 msg_age = time(NULL) - loop_msg->queue_time;
206 if (msg_age > EVENT_TIMEOUT_SEC-1) {
207 msg_move_exec(loop_msg);
216 if (list_empty(&msg_list) == 0) {
217 /* set timeout for remaining queued events */
218 struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}};
219 dbg("next event expires in %li seconds",
220 EVENT_TIMEOUT_SEC - msg_age);
221 setitimer(ITIMER_REAL, &itv, 0);
225 /* receive the msg, do some basic sanity checks, and queue it */
226 static void handle_msg(int sock)
228 struct hotplug_msg *msg;
231 struct cmsghdr *cmsg;
234 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
238 dbg("unable to store message");
243 iov.iov_len = sizeof(struct hotplug_msg);
245 memset(&smsg, 0x00, sizeof(struct msghdr));
248 smsg.msg_control = cred_msg;
249 smsg.msg_controllen = sizeof(cred_msg);
251 retval = recvmsg(sock, &smsg, 0);
254 dbg("unable to receive message");
257 cmsg = CMSG_FIRSTHDR(&smsg);
258 cred = (struct ucred *) CMSG_DATA(cmsg);
260 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
261 dbg("no sender credentials received, message ignored");
265 if (cred->uid != 0) {
266 dbg("sender uid=%i, message ignored", cred->uid);
270 if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
271 dbg("message magic '%s' doesn't match, ignore it", msg->magic);
275 /* if no seqnum is given, we move straight to exec queue */
276 if (msg->seqnum == -1) {
277 list_add(&msg->list, &exec_list);
278 exec_queue_manager();
280 msg_queue_insert(msg);
289 static void sig_handler(int signum)
300 children_waiting = 1;
303 dbg("unhandled signal");
307 static void udev_done(int pid)
309 /* find msg associated with pid and delete it */
310 struct hotplug_msg *msg;
312 list_for_each_entry(msg, &running_list, list) {
313 if (msg->pid == pid) {
314 dbg("<== exec seq %d came back", msg->seqnum);
315 run_queue_delete(msg);
321 int main(int argc, char *argv[])
324 struct sockaddr_un saddr;
328 struct sigaction act;
330 init_logging("udevd");
331 dbg("version %s", UDEV_VERSION);
334 dbg("need to be root, exit");
338 /* set signal handler */
339 act.sa_handler = sig_handler;
340 sigemptyset (&act.sa_mask);
341 act.sa_flags = SA_RESTART;
342 sigaction(SIGINT, &act, NULL);
343 sigaction(SIGTERM, &act, NULL);
345 /* we want these two to interrupt system calls */
347 sigaction(SIGALRM, &act, NULL);
348 sigaction(SIGCHLD, &act, NULL);
350 memset(&saddr, 0x00, sizeof(saddr));
351 saddr.sun_family = AF_LOCAL;
352 /* use abstract namespace for socket path */
353 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
354 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
356 ssock = socket(AF_LOCAL, SOCK_DGRAM, 0);
358 dbg("error getting socket, exit");
362 /* the bind takes care of ensuring only one copy running */
363 retval = bind(ssock, (struct sockaddr *) &saddr, addrlen);
365 dbg("bind failed, exit");
369 /* enable receiving of the sender credentials */
370 setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
375 while(msg_q_timeout) {
380 while(children_waiting) {
381 children_waiting = 0;
382 /* reap all dead children */
384 int pid = waitpid(-1, 0, WNOHANG);
385 if ((pid == -1) || (pid == 0))