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)
119 char *env[] = { action, devpath, NULL };
121 snprintf(action, sizeof(action), "ACTION=%s", msg->action);
122 snprintf(devpath, sizeof(devpath), "DEVPATH=%s", msg->devpath);
128 execle(UDEV_BIN, "udev", msg->subsystem, NULL, env);
129 dbg("exec of child failed");
133 dbg("fork of child failed");
134 run_queue_delete(msg);
137 /* get SIGCHLD in main loop */
138 dbg("==> exec seq %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
143 /* returns already running task with devpath */
144 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
146 struct hotplug_msg *loop_msg;
147 list_for_each_entry(loop_msg, &running_list, list)
148 if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0)
153 /* exec queue management routine executes the events and delays events for the same devpath */
154 static void exec_queue_manager()
156 struct hotplug_msg *loop_msg;
157 struct hotplug_msg *tmp_msg;
158 struct hotplug_msg *msg;
160 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
161 msg = running_with_devpath(loop_msg);
163 /* move event to run list */
164 list_move_tail(&loop_msg->list, &running_list);
166 dbg("moved seq %d to running list", loop_msg->seqnum);
168 dbg("delay seq %d, cause seq %d already working on '%s'",
169 loop_msg->seqnum, msg->seqnum, msg->devpath);
174 static void msg_move_exec(struct hotplug_msg *msg)
176 list_move_tail(&msg->list, &exec_list);
177 exec_queue_manager();
178 expected_seqnum = msg->seqnum+1;
179 dbg("moved seq %d to exec, next expected is %d",
180 msg->seqnum, expected_seqnum);
183 /* msg queue management routine handles the timeouts and dispatches the events */
184 static void msg_queue_manager()
186 struct hotplug_msg *loop_msg;
187 struct hotplug_msg *tmp_msg;
190 dbg("msg queue manager, next expected is %d", expected_seqnum);
192 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
193 /* move event with expected sequence to the exec list */
194 if (loop_msg->seqnum == expected_seqnum) {
195 msg_move_exec(loop_msg);
199 /* move event with expired timeout to the exec list */
200 msg_age = time(NULL) - loop_msg->queue_time;
201 if (msg_age > EVENT_TIMEOUT_SEC-1) {
202 msg_move_exec(loop_msg);
211 if (list_empty(&msg_list) == 0) {
212 /* set timeout for remaining queued events */
213 struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}};
214 dbg("next event expires in %li seconds",
215 EVENT_TIMEOUT_SEC - msg_age);
216 setitimer(ITIMER_REAL, &itv, 0);
220 /* receive the msg, do some basic sanity checks, and queue it */
221 static void handle_msg(int sock)
223 struct hotplug_msg *msg;
226 struct cmsghdr *cmsg;
229 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
233 dbg("unable to store message");
238 iov.iov_len = sizeof(struct hotplug_msg);
240 memset(&smsg, 0x00, sizeof(struct msghdr));
243 smsg.msg_control = cred_msg;
244 smsg.msg_controllen = sizeof(cred_msg);
246 retval = recvmsg(sock, &smsg, 0);
249 dbg("unable to receive message");
252 cmsg = CMSG_FIRSTHDR(&smsg);
253 cred = (struct ucred *) CMSG_DATA(cmsg);
255 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
256 dbg("no sender credentials received, message ignored");
260 if (cred->uid != 0) {
261 dbg("sender uid=%i, message ignored", cred->uid);
265 if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
266 dbg("message magic '%s' doesn't match, ignore it", msg->magic);
270 /* if no seqnum is given, we move straight to exec queue */
271 if (msg->seqnum == -1) {
272 list_add(&msg->list, &exec_list);
273 exec_queue_manager();
275 msg_queue_insert(msg);
284 static void sig_handler(int signum)
295 children_waiting = 1;
298 dbg("unhandled signal");
302 static void udev_done(int pid)
304 /* find msg associated with pid and delete it */
305 struct hotplug_msg *msg;
307 list_for_each_entry(msg, &running_list, list) {
308 if (msg->pid == pid) {
309 dbg("<== exec seq %d came back", msg->seqnum);
310 run_queue_delete(msg);
316 int main(int argc, char *argv[])
319 struct sockaddr_un saddr;
323 struct sigaction act;
325 init_logging("udevd");
328 dbg("need to be root, exit");
332 /* set signal handler */
333 act.sa_handler = sig_handler;
334 sigemptyset (&act.sa_mask);
335 act.sa_flags = SA_RESTART;
336 sigaction(SIGINT, &act, NULL);
337 sigaction(SIGTERM, &act, NULL);
339 /* we want these two to interrupt system calls */
341 sigaction(SIGALRM, &act, NULL);
342 sigaction(SIGCHLD, &act, NULL);
344 memset(&saddr, 0x00, sizeof(saddr));
345 saddr.sun_family = AF_LOCAL;
346 /* use abstract namespace for socket path */
347 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
348 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
350 ssock = socket(AF_LOCAL, SOCK_DGRAM, 0);
352 dbg("error getting socket, exit");
356 /* the bind takes care of ensuring only one copy running */
357 retval = bind(ssock, (struct sockaddr *) &saddr, addrlen);
359 dbg("bind failed, exit");
363 /* enable receiving of the sender credentials */
364 setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
369 while(msg_q_timeout) {
374 while(children_waiting) {
375 children_waiting = 0;
376 /* reap all dead children */
378 int pid = waitpid(-1, 0, WNOHANG);
379 if ((pid == -1) || (pid == 0))