]>
git.ipfire.org Git - thirdparty/systemd.git/blob - udevd.c
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 "klibc_fixups.h"
38 #include <sys/sysinfo.h>
44 #include "udev_version.h"
48 static int pipefds
[2];
49 static int expected_seqnum
= 0;
50 volatile static int children_waiting
;
51 volatile static int run_msg_q
;
52 volatile static int sig_flag
;
53 static int run_exec_q
;
55 static LIST_HEAD(msg_list
);
56 static LIST_HEAD(exec_list
);
57 static LIST_HEAD(running_list
);
59 static void exec_queue_manager(void);
60 static void msg_queue_manager(void);
61 static void user_sighandler(void);
62 static void reap_kids(void);
66 unsigned char logname
[LOGNAME_SIZE
];
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 %d, '%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 %d in queue", msg
->seqnum
);
91 static struct hotplug_msg
*msg_create(void)
93 struct hotplug_msg
*new_msg
;
95 new_msg
= malloc(sizeof(struct hotplug_msg
));
101 static void run_queue_delete(struct hotplug_msg
*msg
)
103 list_del(&msg
->list
);
107 /* orders the message in the queue by sequence number */
108 static void msg_queue_insert(struct hotplug_msg
*msg
)
110 struct hotplug_msg
*loop_msg
;
113 /* sort message by sequence number into list. events
114 * will tend to come in order, so scan the list backwards
116 list_for_each_entry_reverse(loop_msg
, &msg_list
, list
)
117 if (loop_msg
->seqnum
< msg
->seqnum
)
120 /* store timestamp of queuing */
122 msg
->queue_time
= info
.uptime
;
124 list_add(&msg
->list
, &loop_msg
->list
);
125 dbg("queued message seq %d", msg
->seqnum
);
127 /* run msg queue manager */
133 /* forks event and removes event from run queue when finished */
134 static void udev_run(struct hotplug_msg
*msg
)
137 char action
[ACTION_SIZE
];
138 char devpath
[DEVPATH_SIZE
];
139 char *env
[] = { action
, devpath
, NULL
};
141 strcpy(action
, "ACTION=");
142 strfieldcat(action
, msg
->action
);
143 strcpy(devpath
, "DEVPATH=");
144 strfieldcat(devpath
, msg
->devpath
);
150 execle(udev_bin
, "udev", msg
->subsystem
, NULL
, env
);
151 dbg("exec of child failed");
155 dbg("fork of child failed");
156 run_queue_delete(msg
);
157 /* note: we never managed to run, so we had no impact on
158 * running_with_devpath(), so don't bother setting run_exec_q
162 /* get SIGCHLD in main loop */
163 dbg("==> exec seq %d [%d] working at '%s'", msg
->seqnum
, pid
, msg
->devpath
);
168 /* returns already running task with devpath */
169 static struct hotplug_msg
*running_with_devpath(struct hotplug_msg
*msg
)
171 struct hotplug_msg
*loop_msg
;
172 list_for_each_entry(loop_msg
, &running_list
, list
)
173 if (strncmp(loop_msg
->devpath
, msg
->devpath
, sizeof(loop_msg
->devpath
)) == 0)
178 /* exec queue management routine executes the events and delays events for the same devpath */
179 static void exec_queue_manager()
181 struct hotplug_msg
*loop_msg
;
182 struct hotplug_msg
*tmp_msg
;
183 struct hotplug_msg
*msg
;
185 list_for_each_entry_safe(loop_msg
, tmp_msg
, &exec_list
, list
) {
186 msg
= running_with_devpath(loop_msg
);
188 /* move event to run list */
189 list_move_tail(&loop_msg
->list
, &running_list
);
191 dbg("moved seq %d to running list", loop_msg
->seqnum
);
193 dbg("delay seq %d, cause seq %d already working on '%s'",
194 loop_msg
->seqnum
, msg
->seqnum
, msg
->devpath
);
199 static void msg_move_exec(struct hotplug_msg
*msg
)
201 list_move_tail(&msg
->list
, &exec_list
);
203 expected_seqnum
= msg
->seqnum
+1;
204 dbg("moved seq %d to exec, next expected is %d",
205 msg
->seqnum
, expected_seqnum
);
208 /* msg queue management routine handles the timeouts and dispatches the events */
209 static void msg_queue_manager()
211 struct hotplug_msg
*loop_msg
;
212 struct hotplug_msg
*tmp_msg
;
216 dbg("msg queue manager, next expected is %d", expected_seqnum
);
218 list_for_each_entry_safe(loop_msg
, tmp_msg
, &msg_list
, list
) {
219 /* move event with expected sequence to the exec list */
220 if (loop_msg
->seqnum
== expected_seqnum
) {
221 msg_move_exec(loop_msg
);
225 /* move event with expired timeout to the exec list */
227 msg_age
= info
.uptime
- loop_msg
->queue_time
;
228 dbg("seq %d is %li seconds old", loop_msg
->seqnum
, msg_age
);
229 if (msg_age
> EVENT_TIMEOUT_SEC
-1) {
230 msg_move_exec(loop_msg
);
239 /* set timeout for remaining queued events */
240 if (list_empty(&msg_list
) == 0) {
241 struct itimerval itv
= {{0, 0}, {EVENT_TIMEOUT_SEC
- msg_age
, 0}};
242 dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC
- msg_age
);
243 setitimer(ITIMER_REAL
, &itv
, 0);
247 /* receive the msg, do some basic sanity checks, and queue it */
248 static void handle_msg(int sock
)
250 struct hotplug_msg
*msg
;
253 struct cmsghdr
*cmsg
;
256 char cred_msg
[CMSG_SPACE(sizeof(struct ucred
))];
260 dbg("unable to store message");
265 iov
.iov_len
= sizeof(struct hotplug_msg
);
267 memset(&smsg
, 0x00, sizeof(struct msghdr
));
270 smsg
.msg_control
= cred_msg
;
271 smsg
.msg_controllen
= sizeof(cred_msg
);
273 retval
= recvmsg(sock
, &smsg
, 0);
276 dbg("unable to receive message");
279 cmsg
= CMSG_FIRSTHDR(&smsg
);
280 cred
= (struct ucred
*) CMSG_DATA(cmsg
);
282 if (cmsg
== NULL
|| cmsg
->cmsg_type
!= SCM_CREDENTIALS
) {
283 dbg("no sender credentials received, message ignored");
287 if (cred
->uid
!= 0) {
288 dbg("sender uid=%i, message ignored", cred
->uid
);
292 if (strncmp(msg
->magic
, UDEV_MAGIC
, sizeof(UDEV_MAGIC
)) != 0 ) {
293 dbg("message magic '%s' doesn't match, ignore it", msg
->magic
);
297 /* if no seqnum is given, we move straight to exec queue */
298 if (msg
->seqnum
== -1) {
299 list_add(&msg
->list
, &exec_list
);
302 msg_queue_insert(msg
);
311 static void sig_handler(int signum
)
320 /* set flag, then write to pipe if needed */
325 /* set flag, then write to pipe if needed */
326 children_waiting
= 1;
330 dbg("unhandled signal");
335 /* if pipe is empty, write to pipe to force select to return
336 * immediately when it gets called
339 rc
= write(pipefds
[1],&signum
,sizeof(signum
));
341 dbg("unable to write to pipe");
347 static void udev_done(int pid
)
349 /* find msg associated with pid and delete it */
350 struct hotplug_msg
*msg
;
352 list_for_each_entry(msg
, &running_list
, list
) {
353 if (msg
->pid
== pid
) {
354 dbg("<== exec seq %d came back", msg
->seqnum
);
355 run_queue_delete(msg
);
357 /* we want to run the exec queue manager since there may
358 * be events waiting with the devpath of the one that
367 static void reap_kids()
369 /* reap all dead children */
371 int pid
= waitpid(-1, 0, WNOHANG
);
372 if ((pid
== -1) || (pid
== 0))
378 /* just read everything from the pipe and clear the flag,
379 * the useful flags were set in the signal handler
381 static void user_sighandler()
385 int rc
= read(pipefds
[0],&sig
,sizeof(sig
));
394 int main(int argc
, char *argv
[])
396 int ssock
, maxsockplus
;
397 struct sockaddr_un saddr
;
401 struct sigaction act
;
404 init_logging("udevd");
405 dbg("version %s", UDEV_VERSION
);
408 dbg("need to be root, exit");
412 /* setup signal handler pipe */
413 retval
= pipe(pipefds
);
415 dbg("error getting pipes: %s", strerror(errno
));
419 retval
= fcntl(pipefds
[0], F_SETFL
, O_NONBLOCK
);
421 dbg("error fcntl on read pipe: %s", strerror(errno
));
425 retval
= fcntl(pipefds
[1], F_SETFL
, O_NONBLOCK
);
427 dbg("error fcntl on write pipe: %s", strerror(errno
));
431 /* set signal handlers */
432 act
.sa_handler
= sig_handler
;
433 sigemptyset(&act
.sa_mask
);
434 act
.sa_flags
= SA_RESTART
;
435 sigaction(SIGINT
, &act
, NULL
);
436 sigaction(SIGTERM
, &act
, NULL
);
437 sigaction(SIGALRM
, &act
, NULL
);
438 sigaction(SIGCHLD
, &act
, NULL
);
440 memset(&saddr
, 0x00, sizeof(saddr
));
441 saddr
.sun_family
= AF_LOCAL
;
442 /* use abstract namespace for socket path */
443 strcpy(&saddr
.sun_path
[1], UDEVD_SOCK_PATH
);
444 addrlen
= offsetof(struct sockaddr_un
, sun_path
) + strlen(saddr
.sun_path
+1) + 1;
446 ssock
= socket(AF_LOCAL
, SOCK_DGRAM
, 0);
448 dbg("error getting socket, exit");
452 /* the bind takes care of ensuring only one copy running */
453 retval
= bind(ssock
, (struct sockaddr
*) &saddr
, addrlen
);
455 dbg("bind failed, exit");
459 /* enable receiving of the sender credentials */
460 setsockopt(ssock
, SOL_SOCKET
, SO_PASSCRED
, &on
, sizeof(on
));
462 /* possible override of udev binary, used for testing */
463 udev_bin
= getenv("UDEV_BIN");
464 if (udev_bin
!= NULL
)
465 dbg("udev binary is set to '%s'", udev_bin
);
470 FD_SET(ssock
, &readfds
);
471 FD_SET(pipefds
[0], &readfds
);
472 maxsockplus
= ssock
+1;
474 fd_set workreadfds
= readfds
;
475 retval
= select(maxsockplus
, &workreadfds
, NULL
, NULL
, NULL
);
479 dbg("error in select: %s", strerror(errno
));
483 if (FD_ISSET(ssock
, &workreadfds
))
486 if (FD_ISSET(pipefds
[0], &workreadfds
))
489 if (children_waiting
) {
490 children_waiting
= 0;
500 /* this is tricky. exec_queue_manager() loops over exec_list, and
501 * calls running_with_devpath(), which loops over running_list. This gives
502 * O(N*M), which can get *nasty*. Clean up running_list before
503 * calling exec_queue_manager().
505 if (children_waiting
) {
506 children_waiting
= 0;
511 exec_queue_manager();