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 if (msg->seqnum == 0) {
105 dbg("no SEQNUM, move straight to the exec queue");
106 list_add(&msg->list, &exec_list);
111 /* sort message by sequence number into list */
112 list_for_each_entry_reverse(loop_msg, &msg_list, list) {
113 if (loop_msg->seqnum < msg->seqnum)
116 if (loop_msg->seqnum == msg->seqnum) {
117 dbg("ignoring duplicate message seq %llu", msg->seqnum);
122 /* store timestamp of queuing */
124 msg->queue_time = info.uptime;
126 list_add(&msg->list, &loop_msg->list);
127 dbg("queued message seq %llu", msg->seqnum);
129 /* run msg queue manager */
135 /* forks event and removes event from run queue when finished */
136 static void udev_run(struct hotplug_msg *msg)
138 char *const argv[] = { "udev", msg->subsystem, NULL };
147 execve(udev_bin, argv, msg->envp);
148 dbg("exec of child failed");
152 dbg("fork of child failed");
153 run_queue_delete(msg);
154 /* note: we never managed to run, so we had no impact on
155 * running_with_devpath(), so don't bother setting run_exec_q
159 /* get SIGCHLD in main loop */
160 dbg("==> exec seq %llu [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
165 static int compare_devpath(const char *running, const char *waiting)
169 for (i = 0; i < DEVPATH_SIZE; i++) {
170 /* identical device event found */
171 if (running[i] == '\0' && waiting[i] == '\0')
174 /* parent device event found */
175 if (running[i] == '\0' && waiting[i] == '/')
178 /* child device event found */
179 if (running[i] == '/' && waiting[i] == '\0')
182 /* no matching event */
183 if (running[i] != waiting[i])
190 /* returns still running task for the same device, its parent or its physical device */
191 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
193 struct hotplug_msg *loop_msg;
195 if (msg->devpath == NULL)
198 list_for_each_entry(loop_msg, &running_list, list) {
199 if (loop_msg->devpath == NULL)
202 /* return running parent/child device event */
203 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0)
206 /* return running physical device event */
207 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
208 if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0)
215 /* exec queue management routine executes the events and serializes events in the same sequence */
216 static void exec_queue_manager(void)
218 struct hotplug_msg *loop_msg;
219 struct hotplug_msg *tmp_msg;
220 struct hotplug_msg *msg;
222 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
223 msg = running_with_devpath(loop_msg);
225 /* move event to run list */
226 list_move_tail(&loop_msg->list, &running_list);
228 dbg("moved seq %llu to running list", loop_msg->seqnum);
230 dbg("delay seq %llu (%s), cause seq %llu (%s) is still running",
231 loop_msg->seqnum, loop_msg->devpath, msg->seqnum, msg->devpath);
236 static void msg_move_exec(struct hotplug_msg *msg)
238 list_move_tail(&msg->list, &exec_list);
240 expected_seqnum = msg->seqnum+1;
241 dbg("moved seq %llu to exec, next expected is %llu",
242 msg->seqnum, expected_seqnum);
245 /* msg queue management routine handles the timeouts and dispatches the events */
246 static void msg_queue_manager(void)
248 struct hotplug_msg *loop_msg;
249 struct hotplug_msg *tmp_msg;
252 static int timeout = EVENT_INIT_TIMEOUT_SEC;
255 dbg("msg queue manager, next expected is %llu", expected_seqnum);
257 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
258 /* move event with expected sequence to the exec list */
259 if (loop_msg->seqnum == expected_seqnum) {
260 msg_move_exec(loop_msg);
264 /* see if we are in the initialization phase and wait for the very first events */
265 if (init && (info.uptime - startup_time >= INIT_TIME_SEC)) {
267 timeout = EVENT_TIMEOUT_SEC;
268 dbg("initialization phase passed, set timeout to %i seconds", EVENT_TIMEOUT_SEC);
271 /* move event with expired timeout to the exec list */
273 msg_age = info.uptime - loop_msg->queue_time;
274 dbg("seq %llu is %li seconds old", loop_msg->seqnum, msg_age);
275 if (msg_age >= timeout) {
276 msg_move_exec(loop_msg);
285 /* set timeout for remaining queued events */
286 if (list_empty(&msg_list) == 0) {
287 struct itimerval itv = {{0, 0}, {timeout - msg_age, 0}};
288 dbg("next event expires in %li seconds", timeout - msg_age);
289 setitimer(ITIMER_REAL, &itv, NULL);
293 /* receive the udevsend message and do some sanity checks */
294 static struct hotplug_msg *get_udevsend_msg(void)
296 static struct udevsend_msg usend_msg;
297 struct hotplug_msg *msg;
302 struct cmsghdr *cmsg;
305 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
308 memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
309 iov.iov_base = &usend_msg;
310 iov.iov_len = sizeof(struct udevsend_msg);
312 memset(&smsg, 0x00, sizeof(struct msghdr));
315 smsg.msg_control = cred_msg;
316 smsg.msg_controllen = sizeof(cred_msg);
318 size = recvmsg(udevsendsock, &smsg, 0);
321 dbg("unable to receive udevsend message");
324 cmsg = CMSG_FIRSTHDR(&smsg);
325 cred = (struct ucred *) CMSG_DATA(cmsg);
327 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
328 dbg("no sender credentials received, message ignored");
332 if (cred->uid != 0) {
333 dbg("sender uid=%i, message ignored", cred->uid);
337 if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
338 dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
342 envbuf_size = size - offsetof(struct udevsend_msg, envbuf);
343 dbg("envbuf_size=%i", envbuf_size);
344 msg = malloc(sizeof(struct hotplug_msg) + envbuf_size);
348 memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size);
350 /* copy environment buffer and reconstruct envp */
351 memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size);
353 for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) {
357 key = &msg->envbuf[bufpos];
358 keylen = strlen(key);
360 bufpos += keylen + 1;
361 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
363 /* remember some keys for further processing */
364 if (strncmp(key, "ACTION=", 7) == 0)
365 msg->action = &key[7];
367 if (strncmp(key, "DEVPATH=", 8) == 0)
368 msg->devpath = &key[8];
370 if (strncmp(key, "SUBSYSTEM=", 10) == 0)
371 msg->subsystem = &key[10];
373 if (strncmp(key, "SEQNUM=", 7) == 0)
374 msg->seqnum = strtoull(&key[7], NULL, 10);
376 if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
377 msg->physdevpath = &key[12];
379 msg->envp[i++] = "UDEVD_EVENT=1";
385 static void asmlinkage sig_handler(int signum)
395 /* set flag, then write to pipe if needed */
400 /* set flag, then write to pipe if needed */
401 sigchilds_waiting = 1;
407 /* if pipe is empty, write to pipe to force select to return
408 * immediately when it gets called
411 rc = write(pipefds[1],&signum,sizeof(signum));
417 static void udev_done(int pid)
419 /* find msg associated with pid and delete it */
420 struct hotplug_msg *msg;
422 list_for_each_entry(msg, &running_list, list) {
423 if (msg->pid == pid) {
424 dbg("<== exec seq %llu came back", msg->seqnum);
425 run_queue_delete(msg);
427 /* we want to run the exec queue manager since there may
428 * be events waiting with the devpath of the one that
437 static void reap_sigchilds(void)
440 int pid = waitpid(-1, NULL, WNOHANG);
441 if ((pid == -1) || (pid == 0))
447 /* just read everything from the pipe and clear the flag,
448 * the flags was set in the signal handler
450 static void user_sighandler(void)
455 int rc = read(pipefds[0], &sig, sizeof(sig));
463 static int init_udevsend_socket(void)
465 struct sockaddr_un saddr;
467 const int feature_on = 1;
470 memset(&saddr, 0x00, sizeof(saddr));
471 saddr.sun_family = AF_LOCAL;
472 /* use abstract namespace for socket path */
473 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
474 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
476 udevsendsock = socket(AF_LOCAL, SOCK_DGRAM, 0);
477 if (udevsendsock == -1) {
478 dbg("error getting socket, %s", strerror(errno));
482 /* the bind takes care of ensuring only one copy running */
483 retval = bind(udevsendsock, (struct sockaddr *) &saddr, addrlen);
485 dbg("bind failed, %s", strerror(errno));
490 /* enable receiving of the sender credentials */
491 setsockopt(udevsendsock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
496 int main(int argc, char *argv[], char *envp[])
502 struct sigaction act;
505 logging_init("udevd");
506 dbg("version %s", UDEV_VERSION);
509 dbg("need to be root, exit");
513 /* daemonize on request */
514 if (argc == 2 && strcmp(argv[1], "-d") == 0) {
520 dbg("damonized fork running");
523 dbg("fork of daemon failed");
531 /* make sure we don't lock any path */
533 umask(umask(077) | 022);
535 /* Set fds to dev/null */
536 fd = open( "/dev/null", O_RDWR );
544 dbg("error opening /dev/null %s", strerror(errno));
546 /* become session leader */
549 /* setup signal handler pipe */
550 retval = pipe(pipefds);
552 dbg("error getting pipes: %s", strerror(errno));
556 retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
558 dbg("error fcntl on read pipe: %s", strerror(errno));
561 retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
563 dbg("error fcntl on read pipe: %s", strerror(errno));
565 retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
567 dbg("error fcntl on write pipe: %s", strerror(errno));
570 retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
572 dbg("error fcntl on write pipe: %s", strerror(errno));
574 /* set signal handlers */
575 act.sa_handler = (void (*) (int))sig_handler;
576 sigemptyset(&act.sa_mask);
577 act.sa_flags = SA_RESTART;
578 sigaction(SIGINT, &act, NULL);
579 sigaction(SIGTERM, &act, NULL);
580 sigaction(SIGALRM, &act, NULL);
581 sigaction(SIGCHLD, &act, NULL);
583 if (init_udevsend_socket() < 0) {
584 if (errno == EADDRINUSE)
585 dbg("another udevd running, exit");
587 dbg("error initialising udevsend socket: %s", strerror(errno));
592 /* possible override of udev binary, used for testing */
593 udev_bin = getenv("UDEV_BIN");
594 if (udev_bin != NULL)
595 dbg("udev binary is set to '%s'", udev_bin);
599 /* handle special startup timeout*/
601 startup_time = info.uptime;
604 FD_SET(udevsendsock, &readfds);
605 FD_SET(pipefds[0], &readfds);
606 maxsockplus = udevsendsock+1;
608 struct hotplug_msg *msg;
610 fd_set workreadfds = readfds;
611 retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
615 dbg("error in select: %s", strerror(errno));
619 if (FD_ISSET(udevsendsock, &workreadfds)) {
620 msg = get_udevsend_msg();
622 msg_queue_insert(msg);
625 if (FD_ISSET(pipefds[0], &workreadfds))
628 if (sigchilds_waiting) {
629 sigchilds_waiting = 0;
639 /* clean up running_list before calling exec_queue_manager() */
640 if (sigchilds_waiting) {
641 sigchilds_waiting = 0;
646 exec_queue_manager();