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 unsigned char logname[LOGNAME_SIZE];
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 /* returns already running task with devpath */
155 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
157 struct hotplug_msg *loop_msg;
158 list_for_each_entry(loop_msg, &running_list, list) {
159 if (loop_msg->devpath == NULL || msg->devpath == NULL)
162 if (strcmp(loop_msg->devpath, msg->devpath) == 0)
169 /* exec queue management routine executes the events and delays events for the same devpath */
170 static void exec_queue_manager(void)
172 struct hotplug_msg *loop_msg;
173 struct hotplug_msg *tmp_msg;
174 struct hotplug_msg *msg;
176 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
177 msg = running_with_devpath(loop_msg);
179 /* move event to run list */
180 list_move_tail(&loop_msg->list, &running_list);
182 dbg("moved seq %llu to running list", loop_msg->seqnum);
184 dbg("delay seq %llu, cause seq %llu already working on '%s'",
185 loop_msg->seqnum, msg->seqnum, msg->devpath);
190 static void msg_move_exec(struct hotplug_msg *msg)
192 list_move_tail(&msg->list, &exec_list);
194 expected_seqnum = msg->seqnum+1;
195 dbg("moved seq %llu to exec, next expected is %llu",
196 msg->seqnum, expected_seqnum);
199 /* msg queue management routine handles the timeouts and dispatches the events */
200 static void msg_queue_manager(void)
202 struct hotplug_msg *loop_msg;
203 struct hotplug_msg *tmp_msg;
207 dbg("msg queue manager, next expected is %llu", expected_seqnum);
209 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
210 /* move event with expected sequence to the exec list */
211 if (loop_msg->seqnum == expected_seqnum) {
212 msg_move_exec(loop_msg);
216 /* move event with expired timeout to the exec list */
218 msg_age = info.uptime - loop_msg->queue_time;
219 dbg("seq %llu is %li seconds old", loop_msg->seqnum, msg_age);
220 if (msg_age > EVENT_TIMEOUT_SEC-1) {
221 msg_move_exec(loop_msg);
230 /* set timeout for remaining queued events */
231 if (list_empty(&msg_list) == 0) {
232 struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}};
233 dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC - msg_age);
234 setitimer(ITIMER_REAL, &itv, NULL);
238 /* receive the msg, do some basic sanity checks, and queue it */
239 static void handle_udevsend_msg(int sock)
241 static struct udevsend_msg usend_msg;
242 struct hotplug_msg *msg;
247 struct cmsghdr *cmsg;
250 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
253 memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
254 iov.iov_base = &usend_msg;
255 iov.iov_len = sizeof(struct udevsend_msg);
257 memset(&smsg, 0x00, sizeof(struct msghdr));
260 smsg.msg_control = cred_msg;
261 smsg.msg_controllen = sizeof(cred_msg);
263 size = recvmsg(sock, &smsg, 0);
266 dbg("unable to receive message");
269 cmsg = CMSG_FIRSTHDR(&smsg);
270 cred = (struct ucred *) CMSG_DATA(cmsg);
272 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
273 dbg("no sender credentials received, message ignored");
277 if (cred->uid != 0) {
278 dbg("sender uid=%i, message ignored", cred->uid);
282 if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
283 dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
287 envbuf_size = size - offsetof(struct udevsend_msg, envbuf);
288 dbg("envbuf_size=%i", envbuf_size);
289 msg = malloc(sizeof(struct hotplug_msg) + envbuf_size);
290 memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size);
292 /* copy environment buffer and reconstruct envp */
293 memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size);
295 for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) {
299 key = &msg->envbuf[bufpos];
300 keylen = strlen(key);
302 bufpos += keylen + 1;
303 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
305 /* remember some keys for further processing */
306 if (strncmp(key, "ACTION=", 7) == 0)
307 msg->action = &key[7];
309 if (strncmp(key, "DEVPATH=", 8) == 0)
310 msg->devpath = &key[8];
312 if (strncmp(key, "SUBSYSTEM=", 10) == 0)
313 msg->subsystem = &key[10];
315 if (strncmp(key, "SEQNUM=", 7) == 0)
316 msg->seqnum = strtoull(&key[7], NULL, 10);
318 msg->envp[i++] = "MANAGED_EVENT=1";
321 /* if no seqnum is given, we move straight to exec queue */
322 if (msg->seqnum == 0) {
323 list_add(&msg->list, &exec_list);
326 msg_queue_insert(msg);
333 static void asmlinkage sig_handler(int signum)
343 /* set flag, then write to pipe if needed */
348 /* set flag, then write to pipe if needed */
349 sigchilds_waiting = 1;
355 /* if pipe is empty, write to pipe to force select to return
356 * immediately when it gets called
359 rc = write(pipefds[1],&signum,sizeof(signum));
365 static void udev_done(int pid)
367 /* find msg associated with pid and delete it */
368 struct hotplug_msg *msg;
370 list_for_each_entry(msg, &running_list, list) {
371 if (msg->pid == pid) {
372 dbg("<== exec seq %llu came back", msg->seqnum);
373 run_queue_delete(msg);
375 /* we want to run the exec queue manager since there may
376 * be events waiting with the devpath of the one that
385 static void reap_sigchilds(void)
388 int pid = waitpid(-1, NULL, WNOHANG);
389 if ((pid == -1) || (pid == 0))
395 /* just read everything from the pipe and clear the flag,
396 * the flags was set in the signal handler
398 static void user_sighandler(void)
402 int rc = read(pipefds[0], &sig, sizeof(sig));
410 int main(int argc, char *argv[], char *envp[])
413 struct sockaddr_un saddr;
416 const int feature_on = 1;
417 struct sigaction act;
420 logging_init("udevd");
421 dbg("version %s", UDEV_VERSION);
424 dbg("need to be root, exit");
428 /* make sure we don't lock any path */
430 umask(umask(077) | 022);
432 /* Set fds to dev/null */
433 fd = open( "/dev/null", O_RDWR );
435 dbg("error opening /dev/null %s", strerror(errno));
444 /* become session leader */
447 /* setup signal handler pipe */
448 retval = pipe(pipefds);
450 dbg("error getting pipes: %s", strerror(errno));
454 retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
456 dbg("error fcntl on read pipe: %s", strerror(errno));
459 retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
461 dbg("error fcntl on read pipe: %s", strerror(errno));
465 retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
467 dbg("error fcntl on write pipe: %s", strerror(errno));
470 retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
472 dbg("error fcntl on write pipe: %s", strerror(errno));
476 /* set signal handlers */
477 act.sa_handler = (void (*) (int))sig_handler;
478 sigemptyset(&act.sa_mask);
479 act.sa_flags = SA_RESTART;
480 sigaction(SIGINT, &act, NULL);
481 sigaction(SIGTERM, &act, NULL);
482 sigaction(SIGALRM, &act, NULL);
483 sigaction(SIGCHLD, &act, NULL);
485 memset(&saddr, 0x00, sizeof(saddr));
486 saddr.sun_family = AF_LOCAL;
487 /* use abstract namespace for socket path */
488 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
489 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
491 udevsendsock = socket(AF_LOCAL, SOCK_DGRAM, 0);
492 if (udevsendsock == -1) {
493 dbg("error getting socket, exit");
497 /* the bind takes care of ensuring only one copy running */
498 retval = bind(udevsendsock, (struct sockaddr *) &saddr, addrlen);
500 dbg("bind failed, exit");
505 /* enable receiving of the sender credentials */
506 setsockopt(udevsendsock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
508 /* possible override of udev binary, used for testing */
509 udev_bin = getenv("UDEV_BIN");
510 if (udev_bin != NULL)
511 dbg("udev binary is set to '%s'", udev_bin);
516 FD_SET(udevsendsock, &readfds);
517 FD_SET(pipefds[0], &readfds);
518 maxsockplus = udevsendsock+1;
520 fd_set workreadfds = readfds;
521 retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
525 dbg("error in select: %s", strerror(errno));
529 if (FD_ISSET(udevsendsock, &workreadfds))
530 handle_udevsend_msg(udevsendsock);
532 if (FD_ISSET(pipefds[0], &workreadfds))
535 if (sigchilds_waiting) {
536 sigchilds_waiting = 0;
546 /* clean up running_list before calling exec_queue_manager() */
547 if (sigchilds_waiting) {
548 sigchilds_waiting = 0;
553 exec_queue_manager();