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>
36 #include <sys/sysinfo.h>
41 #include "udev_version.h"
42 #include "udev_utils.h"
47 static int udevsendsock;
49 static int pipefds[2];
50 static long startup_time;
51 static unsigned long long expected_seqnum = 0;
52 static volatile int sigchilds_waiting;
53 static volatile int run_msg_q;
54 static volatile int sig_flag;
55 static int run_exec_q;
57 static LIST_HEAD(msg_list);
58 static LIST_HEAD(exec_list);
59 static LIST_HEAD(running_list);
61 static void exec_queue_manager(void);
62 static void msg_queue_manager(void);
63 static void user_sighandler(void);
64 static void reap_sigchilds(void);
68 void log_message (int level, const char *format, ...)
72 va_start(args, format);
73 vsyslog(level, format, args);
78 #define msg_dump(msg) \
79 dbg("msg_dump: sequence %llu, '%s', '%s', '%s'", \
80 msg->seqnum, msg->action, msg->devpath, msg->subsystem);
82 static void msg_dump_queue(void)
85 struct hotplug_msg *msg;
87 list_for_each_entry(msg, &msg_list, list)
88 dbg("sequence %llu in queue", msg->seqnum);
92 static void run_queue_delete(struct hotplug_msg *msg)
98 /* orders the message in the queue by sequence number */
99 static void msg_queue_insert(struct hotplug_msg *msg)
101 struct hotplug_msg *loop_msg;
104 /* sort message by sequence number into list. events
105 * will tend to come in order, so scan the list backwards
107 list_for_each_entry_reverse(loop_msg, &msg_list, list)
108 if (loop_msg->seqnum < msg->seqnum)
111 /* store timestamp of queuing */
113 msg->queue_time = info.uptime;
115 list_add(&msg->list, &loop_msg->list);
116 dbg("queued message seq %llu", msg->seqnum);
118 /* run msg queue manager */
124 /* forks event and removes event from run queue when finished */
125 static void udev_run(struct hotplug_msg *msg)
127 char *const argv[] = { "udev", msg->subsystem, NULL };
136 execve(udev_bin, argv, msg->envp);
137 dbg("exec of child failed");
141 dbg("fork of child failed");
142 run_queue_delete(msg);
143 /* note: we never managed to run, so we had no impact on
144 * running_with_devpath(), so don't bother setting run_exec_q
148 /* get SIGCHLD in main loop */
149 dbg("==> exec seq %llu [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
154 static int compare_devpath(const char *running, const char *waiting)
158 for (i = 0; i < DEVPATH_SIZE; i++) {
159 /* identical device event found */
160 if (running[i] == '\0' && waiting[i] == '\0')
163 /* parent device event found */
164 if (running[i] == '\0' && waiting[i] == '/')
167 /* child device event found */
168 if (running[i] == '/' && waiting[i] == '\0')
171 /* no matching event */
172 if (running[i] != waiting[i])
179 /* returns still running task for the same device, its parent or its physical device */
180 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
182 struct hotplug_msg *loop_msg;
184 if (msg->devpath == NULL)
187 list_for_each_entry(loop_msg, &running_list, list) {
188 if (loop_msg->devpath == NULL)
191 /* return running parent/child device event */
192 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0)
195 /* return running physical device event */
196 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
197 if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0)
204 /* exec queue management routine executes the events and serializes events in the same sequence */
205 static void exec_queue_manager(void)
207 struct hotplug_msg *loop_msg;
208 struct hotplug_msg *tmp_msg;
209 struct hotplug_msg *msg;
211 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
212 msg = running_with_devpath(loop_msg);
214 /* move event to run list */
215 list_move_tail(&loop_msg->list, &running_list);
217 dbg("moved seq %llu to running list", loop_msg->seqnum);
219 dbg("delay seq %llu (%s), cause seq %llu (%s) is still running",
220 loop_msg->seqnum, loop_msg->devpath, msg->seqnum, msg->devpath);
225 static void msg_move_exec(struct hotplug_msg *msg)
227 list_move_tail(&msg->list, &exec_list);
229 expected_seqnum = msg->seqnum+1;
230 dbg("moved seq %llu to exec, next expected is %llu",
231 msg->seqnum, expected_seqnum);
234 /* msg queue management routine handles the timeouts and dispatches the events */
235 static void msg_queue_manager(void)
237 struct hotplug_msg *loop_msg;
238 struct hotplug_msg *tmp_msg;
241 static int timeout = EVENT_INIT_TIMEOUT_SEC;
244 dbg("msg queue manager, next expected is %llu", expected_seqnum);
246 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
247 /* move event with expected sequence to the exec list */
248 if (loop_msg->seqnum == expected_seqnum) {
249 msg_move_exec(loop_msg);
253 /* see if we are in the initialization phase and wait for the very first events */
254 if (init && (info.uptime - startup_time >= INIT_TIME_SEC)) {
256 timeout = EVENT_TIMEOUT_SEC;
257 dbg("initialization phase passed, set timeout to %i seconds", EVENT_TIMEOUT_SEC);
260 /* move event with expired timeout to the exec list */
262 msg_age = info.uptime - loop_msg->queue_time;
263 dbg("seq %llu is %li seconds old", loop_msg->seqnum, msg_age);
264 if (msg_age >= timeout) {
265 msg_move_exec(loop_msg);
274 /* set timeout for remaining queued events */
275 if (list_empty(&msg_list) == 0) {
276 struct itimerval itv = {{0, 0}, {timeout - msg_age, 0}};
277 dbg("next event expires in %li seconds", timeout - msg_age);
278 setitimer(ITIMER_REAL, &itv, NULL);
282 /* receive the msg, do some basic sanity checks, and queue it */
283 static void handle_udevsend_msg(int sock)
285 static struct udevsend_msg usend_msg;
286 struct hotplug_msg *msg;
291 struct cmsghdr *cmsg;
294 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
297 memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
298 iov.iov_base = &usend_msg;
299 iov.iov_len = sizeof(struct udevsend_msg);
301 memset(&smsg, 0x00, sizeof(struct msghdr));
304 smsg.msg_control = cred_msg;
305 smsg.msg_controllen = sizeof(cred_msg);
307 size = recvmsg(sock, &smsg, 0);
310 dbg("unable to receive message");
313 cmsg = CMSG_FIRSTHDR(&smsg);
314 cred = (struct ucred *) CMSG_DATA(cmsg);
316 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
317 dbg("no sender credentials received, message ignored");
321 if (cred->uid != 0) {
322 dbg("sender uid=%i, message ignored", cred->uid);
326 if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
327 dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
331 envbuf_size = size - offsetof(struct udevsend_msg, envbuf);
332 dbg("envbuf_size=%i", envbuf_size);
333 msg = malloc(sizeof(struct hotplug_msg) + envbuf_size);
334 memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size);
336 /* copy environment buffer and reconstruct envp */
337 memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size);
339 for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) {
343 key = &msg->envbuf[bufpos];
344 keylen = strlen(key);
346 bufpos += keylen + 1;
347 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
349 /* remember some keys for further processing */
350 if (strncmp(key, "ACTION=", 7) == 0)
351 msg->action = &key[7];
353 if (strncmp(key, "DEVPATH=", 8) == 0)
354 msg->devpath = &key[8];
356 if (strncmp(key, "SUBSYSTEM=", 10) == 0)
357 msg->subsystem = &key[10];
359 if (strncmp(key, "SEQNUM=", 7) == 0)
360 msg->seqnum = strtoull(&key[7], NULL, 10);
362 if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
363 msg->physdevpath = &key[12];
365 msg->envp[i++] = "UDEVD_EVENT=1";
368 /* if no seqnum is given, we move straight to exec queue */
369 if (msg->seqnum == 0) {
370 list_add(&msg->list, &exec_list);
373 msg_queue_insert(msg);
380 static void asmlinkage sig_handler(int signum)
390 /* set flag, then write to pipe if needed */
395 /* set flag, then write to pipe if needed */
396 sigchilds_waiting = 1;
402 /* if pipe is empty, write to pipe to force select to return
403 * immediately when it gets called
406 rc = write(pipefds[1],&signum,sizeof(signum));
412 static void udev_done(int pid)
414 /* find msg associated with pid and delete it */
415 struct hotplug_msg *msg;
417 list_for_each_entry(msg, &running_list, list) {
418 if (msg->pid == pid) {
419 dbg("<== exec seq %llu came back", msg->seqnum);
420 run_queue_delete(msg);
422 /* we want to run the exec queue manager since there may
423 * be events waiting with the devpath of the one that
432 static void reap_sigchilds(void)
435 int pid = waitpid(-1, NULL, WNOHANG);
436 if ((pid == -1) || (pid == 0))
442 /* just read everything from the pipe and clear the flag,
443 * the flags was set in the signal handler
445 static void user_sighandler(void)
449 int rc = read(pipefds[0], &sig, sizeof(sig));
457 int main(int argc, char *argv[], char *envp[])
461 struct sockaddr_un saddr;
464 const int feature_on = 1;
465 struct sigaction act;
468 logging_init("udevd");
469 dbg("version %s", UDEV_VERSION);
472 dbg("need to be root, exit");
476 /* make sure we don't lock any path */
478 umask(umask(077) | 022);
480 /* Set fds to dev/null */
481 fd = open( "/dev/null", O_RDWR );
483 dbg("error opening /dev/null %s", strerror(errno));
492 /* become session leader */
495 /* setup signal handler pipe */
496 retval = pipe(pipefds);
498 dbg("error getting pipes: %s", strerror(errno));
502 retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
504 dbg("error fcntl on read pipe: %s", strerror(errno));
507 retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
509 dbg("error fcntl on read pipe: %s", strerror(errno));
513 retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
515 dbg("error fcntl on write pipe: %s", strerror(errno));
518 retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
520 dbg("error fcntl on write pipe: %s", strerror(errno));
524 /* set signal handlers */
525 act.sa_handler = (void (*) (int))sig_handler;
526 sigemptyset(&act.sa_mask);
527 act.sa_flags = SA_RESTART;
528 sigaction(SIGINT, &act, NULL);
529 sigaction(SIGTERM, &act, NULL);
530 sigaction(SIGALRM, &act, NULL);
531 sigaction(SIGCHLD, &act, NULL);
533 memset(&saddr, 0x00, sizeof(saddr));
534 saddr.sun_family = AF_LOCAL;
535 /* use abstract namespace for socket path */
536 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
537 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
539 udevsendsock = socket(AF_LOCAL, SOCK_DGRAM, 0);
540 if (udevsendsock == -1) {
541 dbg("error getting socket, exit");
545 /* the bind takes care of ensuring only one copy running */
546 retval = bind(udevsendsock, (struct sockaddr *) &saddr, addrlen);
548 dbg("bind failed, exit");
553 /* enable receiving of the sender credentials */
554 setsockopt(udevsendsock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
556 /* possible override of udev binary, used for testing */
557 udev_bin = getenv("UDEV_BIN");
558 if (udev_bin != NULL)
559 dbg("udev binary is set to '%s'", udev_bin);
563 /* handle special startup timeout*/
565 startup_time = info.uptime;
568 FD_SET(udevsendsock, &readfds);
569 FD_SET(pipefds[0], &readfds);
570 maxsockplus = udevsendsock+1;
572 fd_set workreadfds = readfds;
573 retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
577 dbg("error in select: %s", strerror(errno));
581 if (FD_ISSET(udevsendsock, &workreadfds))
582 handle_udevsend_msg(udevsendsock);
584 if (FD_ISSET(pipefds[0], &workreadfds))
587 if (sigchilds_waiting) {
588 sigchilds_waiting = 0;
598 /* clean up running_list before calling exec_queue_manager() */
599 if (sigchilds_waiting) {
600 sigchilds_waiting = 0;
605 exec_queue_manager();