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 unsigned long long expected_seqnum = 0;
51 static volatile int sigchilds_waiting;
52 static volatile int run_msg_q;
53 static volatile int sig_flag;
54 static int run_exec_q;
56 static LIST_HEAD(msg_list);
57 static LIST_HEAD(exec_list);
58 static LIST_HEAD(running_list);
60 static void exec_queue_manager(void);
61 static void msg_queue_manager(void);
62 static void user_sighandler(void);
63 static void reap_sigchilds(void);
67 void log_message (int level, const char *format, ...)
71 va_start(args, format);
72 vsyslog(level, format, args);
77 #define msg_dump(msg) \
78 dbg("msg_dump: sequence %llu, '%s', '%s', '%s'", \
79 msg->seqnum, msg->action, msg->devpath, msg->subsystem);
81 static void msg_dump_queue(void)
84 struct hotplug_msg *msg;
86 list_for_each_entry(msg, &msg_list, list)
87 dbg("sequence %llu in queue", msg->seqnum);
91 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;
103 /* sort message by sequence number into list. events
104 * will tend to come in order, so scan the list backwards
106 list_for_each_entry_reverse(loop_msg, &msg_list, list)
107 if (loop_msg->seqnum < msg->seqnum)
110 /* store timestamp of queuing */
112 msg->queue_time = info.uptime;
114 list_add(&msg->list, &loop_msg->list);
115 dbg("queued message seq %llu", msg->seqnum);
117 /* run msg queue manager */
123 /* forks event and removes event from run queue when finished */
124 static void udev_run(struct hotplug_msg *msg)
126 char *const argv[] = { "udev", msg->subsystem, NULL };
135 execve(udev_bin, argv, msg->envp);
136 dbg("exec of child failed");
140 dbg("fork of child failed");
141 run_queue_delete(msg);
142 /* note: we never managed to run, so we had no impact on
143 * running_with_devpath(), so don't bother setting run_exec_q
147 /* get SIGCHLD in main loop */
148 dbg("==> exec seq %llu [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
153 /* returns still running task for the same event sequence */
154 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
156 struct hotplug_msg *loop_msg;
159 list_for_each_entry(loop_msg, &running_list, list) {
160 if (loop_msg->devpath == NULL || msg->devpath == NULL)
163 /* is a parent or child device event still running */
164 for (i = 0; i < DEVPATH_SIZE; i++) {
165 if (loop_msg->devpath[i] == '\0' || msg->devpath[i] == '\0')
168 if (loop_msg->devpath[i] != msg->devpath[i])
172 /* is the physical device event still running on an add sequence */
173 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
174 for (i = 0; i < DEVPATH_SIZE; i++) {
175 if (loop_msg->devpath[i] == '\0' || msg->physdevpath[i] == '\0')
178 if (loop_msg->devpath[i] != msg->physdevpath[i])
186 /* exec queue management routine executes the events and serializes events in the same sequence */
187 static void exec_queue_manager(void)
189 struct hotplug_msg *loop_msg;
190 struct hotplug_msg *tmp_msg;
191 struct hotplug_msg *msg;
193 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
194 msg = running_with_devpath(loop_msg);
196 /* move event to run list */
197 list_move_tail(&loop_msg->list, &running_list);
199 dbg("moved seq %llu to running list", loop_msg->seqnum);
201 dbg("delay seq %llu (%s), cause seq %llu (%s) is still running",
202 loop_msg->seqnum, loop_msg->devpath, msg->seqnum, msg->devpath);
207 static void msg_move_exec(struct hotplug_msg *msg)
209 list_move_tail(&msg->list, &exec_list);
211 expected_seqnum = msg->seqnum+1;
212 dbg("moved seq %llu to exec, next expected is %llu",
213 msg->seqnum, expected_seqnum);
216 /* msg queue management routine handles the timeouts and dispatches the events */
217 static void msg_queue_manager(void)
219 struct hotplug_msg *loop_msg;
220 struct hotplug_msg *tmp_msg;
224 dbg("msg queue manager, next expected is %llu", expected_seqnum);
226 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
227 /* move event with expected sequence to the exec list */
228 if (loop_msg->seqnum == expected_seqnum) {
229 msg_move_exec(loop_msg);
233 /* move event with expired timeout to the exec list */
235 msg_age = info.uptime - loop_msg->queue_time;
236 dbg("seq %llu is %li seconds old", loop_msg->seqnum, msg_age);
237 if (msg_age > EVENT_TIMEOUT_SEC-1) {
238 msg_move_exec(loop_msg);
247 /* set timeout for remaining queued events */
248 if (list_empty(&msg_list) == 0) {
249 struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}};
250 dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC - msg_age);
251 setitimer(ITIMER_REAL, &itv, NULL);
255 /* receive the msg, do some basic sanity checks, and queue it */
256 static void handle_udevsend_msg(int sock)
258 static struct udevsend_msg usend_msg;
259 struct hotplug_msg *msg;
264 struct cmsghdr *cmsg;
267 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
270 memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
271 iov.iov_base = &usend_msg;
272 iov.iov_len = sizeof(struct udevsend_msg);
274 memset(&smsg, 0x00, sizeof(struct msghdr));
277 smsg.msg_control = cred_msg;
278 smsg.msg_controllen = sizeof(cred_msg);
280 size = recvmsg(sock, &smsg, 0);
283 dbg("unable to receive message");
286 cmsg = CMSG_FIRSTHDR(&smsg);
287 cred = (struct ucred *) CMSG_DATA(cmsg);
289 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
290 dbg("no sender credentials received, message ignored");
294 if (cred->uid != 0) {
295 dbg("sender uid=%i, message ignored", cred->uid);
299 if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
300 dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
304 envbuf_size = size - offsetof(struct udevsend_msg, envbuf);
305 dbg("envbuf_size=%i", envbuf_size);
306 msg = malloc(sizeof(struct hotplug_msg) + envbuf_size);
307 memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size);
309 /* copy environment buffer and reconstruct envp */
310 memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size);
312 for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) {
316 key = &msg->envbuf[bufpos];
317 keylen = strlen(key);
319 bufpos += keylen + 1;
320 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
322 /* remember some keys for further processing */
323 if (strncmp(key, "ACTION=", 7) == 0)
324 msg->action = &key[7];
326 if (strncmp(key, "DEVPATH=", 8) == 0)
327 msg->devpath = &key[8];
329 if (strncmp(key, "SUBSYSTEM=", 10) == 0)
330 msg->subsystem = &key[10];
332 if (strncmp(key, "SEQNUM=", 7) == 0)
333 msg->seqnum = strtoull(&key[7], NULL, 10);
335 if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
336 msg->physdevpath = &key[12];
338 msg->envp[i++] = "UDEVD_EVENT=1";
341 /* if no seqnum is given, we move straight to exec queue */
342 if (msg->seqnum == 0) {
343 list_add(&msg->list, &exec_list);
346 msg_queue_insert(msg);
353 static void asmlinkage sig_handler(int signum)
363 /* set flag, then write to pipe if needed */
368 /* set flag, then write to pipe if needed */
369 sigchilds_waiting = 1;
375 /* if pipe is empty, write to pipe to force select to return
376 * immediately when it gets called
379 rc = write(pipefds[1],&signum,sizeof(signum));
385 static void udev_done(int pid)
387 /* find msg associated with pid and delete it */
388 struct hotplug_msg *msg;
390 list_for_each_entry(msg, &running_list, list) {
391 if (msg->pid == pid) {
392 dbg("<== exec seq %llu came back", msg->seqnum);
393 run_queue_delete(msg);
395 /* we want to run the exec queue manager since there may
396 * be events waiting with the devpath of the one that
405 static void reap_sigchilds(void)
408 int pid = waitpid(-1, NULL, WNOHANG);
409 if ((pid == -1) || (pid == 0))
415 /* just read everything from the pipe and clear the flag,
416 * the flags was set in the signal handler
418 static void user_sighandler(void)
422 int rc = read(pipefds[0], &sig, sizeof(sig));
430 int main(int argc, char *argv[], char *envp[])
433 struct sockaddr_un saddr;
436 const int feature_on = 1;
437 struct sigaction act;
440 logging_init("udevd");
441 dbg("version %s", UDEV_VERSION);
444 dbg("need to be root, exit");
448 /* make sure we don't lock any path */
450 umask(umask(077) | 022);
452 /* Set fds to dev/null */
453 fd = open( "/dev/null", O_RDWR );
455 dbg("error opening /dev/null %s", strerror(errno));
464 /* become session leader */
467 /* setup signal handler pipe */
468 retval = pipe(pipefds);
470 dbg("error getting pipes: %s", strerror(errno));
474 retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
476 dbg("error fcntl on read pipe: %s", strerror(errno));
479 retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
481 dbg("error fcntl on read pipe: %s", strerror(errno));
485 retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
487 dbg("error fcntl on write pipe: %s", strerror(errno));
490 retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
492 dbg("error fcntl on write pipe: %s", strerror(errno));
496 /* set signal handlers */
497 act.sa_handler = (void (*) (int))sig_handler;
498 sigemptyset(&act.sa_mask);
499 act.sa_flags = SA_RESTART;
500 sigaction(SIGINT, &act, NULL);
501 sigaction(SIGTERM, &act, NULL);
502 sigaction(SIGALRM, &act, NULL);
503 sigaction(SIGCHLD, &act, NULL);
505 memset(&saddr, 0x00, sizeof(saddr));
506 saddr.sun_family = AF_LOCAL;
507 /* use abstract namespace for socket path */
508 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
509 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
511 udevsendsock = socket(AF_LOCAL, SOCK_DGRAM, 0);
512 if (udevsendsock == -1) {
513 dbg("error getting socket, exit");
517 /* the bind takes care of ensuring only one copy running */
518 retval = bind(udevsendsock, (struct sockaddr *) &saddr, addrlen);
520 dbg("bind failed, exit");
525 /* enable receiving of the sender credentials */
526 setsockopt(udevsendsock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
528 /* possible override of udev binary, used for testing */
529 udev_bin = getenv("UDEV_BIN");
530 if (udev_bin != NULL)
531 dbg("udev binary is set to '%s'", udev_bin);
536 FD_SET(udevsendsock, &readfds);
537 FD_SET(pipefds[0], &readfds);
538 maxsockplus = udevsendsock+1;
540 fd_set workreadfds = readfds;
541 retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
545 dbg("error in select: %s", strerror(errno));
549 if (FD_ISSET(udevsendsock, &workreadfds))
550 handle_udevsend_msg(udevsendsock);
552 if (FD_ISSET(pipefds[0], &workreadfds))
555 if (sigchilds_waiting) {
556 sigchilds_waiting = 0;
566 /* clean up running_list before calling exec_queue_manager() */
567 if (sigchilds_waiting) {
568 sigchilds_waiting = 0;
573 exec_queue_manager();