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>
39 #include "udev_version.h"
43 unsigned char logname[42];
44 static int expected_seqnum = 0;
45 volatile static int children_waiting;
46 volatile static int msg_q_timeout;
50 LIST_HEAD(running_list);
52 static void exec_queue_manager(void);
53 static void msg_queue_manager(void);
55 static void msg_dump_queue(void)
57 struct hotplug_msg *msg;
59 list_for_each_entry(msg, &msg_list, list)
60 dbg("sequence %d in queue", msg->seqnum);
63 static void msg_dump(struct hotplug_msg *msg)
65 dbg("sequence %d, '%s', '%s', '%s'",
66 msg->seqnum, msg->action, msg->devpath, msg->subsystem);
69 static struct hotplug_msg *msg_create(void)
71 struct hotplug_msg *new_msg;
73 new_msg = malloc(sizeof(struct hotplug_msg));
79 static void run_queue_delete(struct hotplug_msg *msg)
86 /* orders the message in the queue by sequence number */
87 static void msg_queue_insert(struct hotplug_msg *msg)
89 struct hotplug_msg *loop_msg;
91 /* sort message by sequence number into list*/
92 list_for_each_entry(loop_msg, &msg_list, list)
93 if (loop_msg->seqnum > msg->seqnum)
95 list_add_tail(&msg->list, &loop_msg->list);
96 dbg("queued message seq %d", msg->seqnum);
98 /* store timestamp of queuing */
99 msg->queue_time = time(NULL);
101 /* run msg queue manager */
107 /* forks event and removes event from run queue when finished */
108 static void udev_run(struct hotplug_msg *msg)
111 setenv("ACTION", msg->action, 1);
112 setenv("DEVPATH", msg->devpath, 1);
118 execl(UDEV_BIN, "udev", msg->subsystem, NULL);
119 dbg("exec of child failed");
123 dbg("fork of child failed");
124 run_queue_delete(msg);
127 /* get SIGCHLD in main loop */
128 dbg("==> exec seq %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
133 /* returns already running task with devpath */
134 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
136 struct hotplug_msg *loop_msg;
137 list_for_each_entry(loop_msg, &running_list, list)
138 if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0)
143 /* exec queue management routine executes the events and delays events for the same devpath */
144 static void exec_queue_manager()
146 struct hotplug_msg *loop_msg;
147 struct hotplug_msg *tmp_msg;
148 struct hotplug_msg *msg;
150 list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
151 msg = running_with_devpath(loop_msg);
153 /* move event to run list */
154 list_move_tail(&loop_msg->list, &running_list);
156 dbg("moved seq %d to running list", loop_msg->seqnum);
158 dbg("delay seq %d, cause seq %d already working on '%s'",
159 loop_msg->seqnum, msg->seqnum, msg->devpath);
164 static void msg_move_exec(struct hotplug_msg *msg)
166 list_move_tail(&msg->list, &exec_list);
167 exec_queue_manager();
168 expected_seqnum = msg->seqnum+1;
169 dbg("moved seq %d to exec, next expected is %d",
170 msg->seqnum, expected_seqnum);
173 /* msg queue management routine handles the timeouts and dispatches the events */
174 static void msg_queue_manager()
176 struct hotplug_msg *loop_msg;
177 struct hotplug_msg *tmp_msg;
180 dbg("msg queue manager, next expected is %d", expected_seqnum);
182 list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
183 /* move event with expected sequence to the exec list */
184 if (loop_msg->seqnum == expected_seqnum) {
185 msg_move_exec(loop_msg);
189 /* move event with expired timeout to the exec list */
190 msg_age = time(NULL) - loop_msg->queue_time;
191 if (msg_age > EVENT_TIMEOUT_SEC-1) {
192 msg_move_exec(loop_msg);
201 if (list_empty(&msg_list) == 0) {
202 /* set timeout for remaining queued events */
203 struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}};
204 dbg("next event expires in %li seconds",
205 EVENT_TIMEOUT_SEC - msg_age);
206 setitimer(ITIMER_REAL, &itv, 0);
210 /* receive the msg, do some basic sanity checks, and queue it */
211 static void handle_msg(int sock)
213 struct hotplug_msg *msg;
218 dbg("unable to store message");
222 retval = recv(sock, msg, sizeof(struct hotplug_msg), 0);
225 dbg("unable to receive message");
229 if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
230 dbg("message magic '%s' doesn't match, ignore it", msg->magic);
235 /* if no seqnum is given, we move straight to exec queue */
236 if (msg->seqnum == -1) {
237 list_add(&msg->list, &exec_list);
238 exec_queue_manager();
240 msg_queue_insert(msg);
244 static void sig_handler(int signum)
255 children_waiting = 1;
258 dbg("unhandled signal");
262 static void udev_done(int pid)
264 /* find msg associated with pid and delete it */
265 struct hotplug_msg *msg;
267 list_for_each_entry(msg, &running_list, list) {
268 if (msg->pid == pid) {
269 dbg("<== exec seq %d came back", msg->seqnum);
270 run_queue_delete(msg);
276 int main(int argc, char *argv[])
279 struct sockaddr_un saddr;
283 init_logging("udevd");
285 signal(SIGINT, sig_handler);
286 signal(SIGTERM, sig_handler);
287 signal(SIGALRM, sig_handler);
288 signal(SIGCHLD, sig_handler);
290 /* we want these two to interrupt system calls */
291 siginterrupt(SIGALRM, 1);
292 siginterrupt(SIGCHLD, 1);
294 memset(&saddr, 0x00, sizeof(saddr));
295 saddr.sun_family = AF_LOCAL;
296 /* use abstract namespace for socket path */
297 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
298 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
300 ssock = socket(AF_LOCAL, SOCK_DGRAM, 0);
302 dbg("error getting socket");
306 /* the bind takes care of ensuring only one copy running */
307 retval = bind(ssock, &saddr, addrlen);
309 dbg("bind failed\n");
316 while(msg_q_timeout) {
321 while(children_waiting) {
322 children_waiting = 0;
323 /* reap all dead children */
325 int pid = waitpid(-1, 0, WNOHANG);
326 if ((pid == -1) || (pid == 0))