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Commit | Line | Data |
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7fafc032 | 1 | /* |
53921bfa | 2 | * udevd.c - hotplug event serializer |
7fafc032 | 3 | * |
7fafc032 | 4 | * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org> |
2f6cbd19 | 5 | * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca> |
7fafc032 KS |
6 | * |
7 | * | |
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. | |
11 | * | |
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. | |
16 | * | |
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. | |
20 | * | |
21 | */ | |
22 | ||
a695feae | 23 | #include <stddef.h> |
90c210eb | 24 | #include <sys/wait.h> |
7fafc032 KS |
25 | #include <signal.h> |
26 | #include <unistd.h> | |
27 | #include <errno.h> | |
28 | #include <stdio.h> | |
29 | #include <stdlib.h> | |
30 | #include <string.h> | |
e5a2989e | 31 | #include <sys/time.h> |
53921bfa KS |
32 | #include <sys/types.h> |
33 | #include <sys/socket.h> | |
34 | #include <sys/un.h> | |
f27125f9 | 35 | #include <fcntl.h> |
e5a2989e KS |
36 | #include "klibc_fixups.h" |
37 | #ifndef __KLIBC__ | |
38 | #include <sys/sysinfo.h> | |
39 | #endif | |
7fafc032 | 40 | |
a695feae | 41 | #include "list.h" |
7fafc032 | 42 | #include "udev.h" |
c81b35c0 | 43 | #include "udev_lib.h" |
35b7d88c | 44 | #include "udev_version.h" |
7fafc032 KS |
45 | #include "udevd.h" |
46 | #include "logging.h" | |
47 | ||
f27125f9 | 48 | static int pipefds[2]; |
53921bfa | 49 | static int expected_seqnum = 0; |
2f6cbd19 | 50 | volatile static int children_waiting; |
f27125f9 | 51 | volatile static int run_msg_q; |
52 | volatile static int sig_flag; | |
53 | static int run_exec_q; | |
7fafc032 | 54 | |
4a539daf KS |
55 | static LIST_HEAD(msg_list); |
56 | static LIST_HEAD(exec_list); | |
57 | static LIST_HEAD(running_list); | |
7fafc032 | 58 | |
2f6cbd19 KS |
59 | static void exec_queue_manager(void); |
60 | static void msg_queue_manager(void); | |
f27125f9 | 61 | static void user_sighandler(void); |
62 | static void reap_kids(void); | |
7fafc032 | 63 | |
d026a35d | 64 | #ifdef LOG |
d00bd172 | 65 | unsigned char logname[LOGNAME_SIZE]; |
d026a35d | 66 | void log_message (int level, const char *format, ...) |
51a8bb2f | 67 | { |
d026a35d GKH |
68 | va_list args; |
69 | ||
70 | va_start(args, format); | |
71 | vsyslog(level, format, args); | |
72 | va_end(args); | |
51a8bb2f | 73 | } |
d026a35d | 74 | #endif |
51a8bb2f | 75 | |
b6bf0b12 KS |
76 | #define msg_dump(msg) \ |
77 | dbg("msg_dump: sequence %d, '%s', '%s', '%s'", \ | |
78 | msg->seqnum, msg->action, msg->devpath, msg->subsystem); | |
79 | ||
53921bfa | 80 | static void msg_dump_queue(void) |
7fafc032 | 81 | { |
f27125f9 | 82 | #ifdef DEBUG |
53921bfa | 83 | struct hotplug_msg *msg; |
7fafc032 | 84 | |
53921bfa KS |
85 | list_for_each_entry(msg, &msg_list, list) |
86 | dbg("sequence %d in queue", msg->seqnum); | |
f27125f9 | 87 | #endif |
35b7d88c KS |
88 | } |
89 | ||
53921bfa | 90 | static struct hotplug_msg *msg_create(void) |
35b7d88c | 91 | { |
53921bfa | 92 | struct hotplug_msg *new_msg; |
35b7d88c | 93 | |
53921bfa | 94 | new_msg = malloc(sizeof(struct hotplug_msg)); |
2f6cbd19 | 95 | if (new_msg == NULL) |
53921bfa | 96 | dbg("error malloc"); |
53921bfa | 97 | return new_msg; |
35b7d88c KS |
98 | } |
99 | ||
2f6cbd19 | 100 | static void run_queue_delete(struct hotplug_msg *msg) |
8e2229c4 | 101 | { |
2f6cbd19 KS |
102 | list_del(&msg->list); |
103 | free(msg); | |
8e2229c4 KS |
104 | } |
105 | ||
53921bfa KS |
106 | /* orders the message in the queue by sequence number */ |
107 | static void msg_queue_insert(struct hotplug_msg *msg) | |
35b7d88c | 108 | { |
53921bfa | 109 | struct hotplug_msg *loop_msg; |
e5a2989e | 110 | struct sysinfo info; |
35b7d88c | 111 | |
f27125f9 | 112 | /* sort message by sequence number into list. events |
113 | * will tend to come in order, so scan the list backwards | |
114 | */ | |
115 | list_for_each_entry_reverse(loop_msg, &msg_list, list) | |
116 | if (loop_msg->seqnum < msg->seqnum) | |
53921bfa | 117 | break; |
35b7d88c | 118 | |
53921bfa | 119 | /* store timestamp of queuing */ |
e5a2989e KS |
120 | sysinfo(&info); |
121 | msg->queue_time = info.uptime; | |
122 | ||
123 | list_add(&msg->list, &loop_msg->list); | |
124 | dbg("queued message seq %d", msg->seqnum); | |
35b7d88c | 125 | |
2f6cbd19 | 126 | /* run msg queue manager */ |
f27125f9 | 127 | run_msg_q = 1; |
7fafc032 | 128 | |
53921bfa | 129 | return ; |
7fafc032 KS |
130 | } |
131 | ||
53921bfa | 132 | /* forks event and removes event from run queue when finished */ |
2f6cbd19 | 133 | static void udev_run(struct hotplug_msg *msg) |
7fafc032 | 134 | { |
90c210eb | 135 | pid_t pid; |
e964c2c0 KS |
136 | char action[ACTION_SIZE]; |
137 | char devpath[DEVPATH_SIZE]; | |
f8911dbb KS |
138 | char *env[] = { action, devpath, NULL }; |
139 | ||
9b28a52a KS |
140 | strcpy(action, "ACTION="); |
141 | strfieldcat(action, msg->action); | |
142 | strcpy(devpath, "DEVPATH="); | |
143 | strfieldcat(devpath, msg->devpath); | |
90c210eb KS |
144 | |
145 | pid = fork(); | |
146 | switch (pid) { | |
147 | case 0: | |
33db4b8d | 148 | /* child */ |
f8911dbb | 149 | execle(UDEV_BIN, "udev", msg->subsystem, NULL, env); |
33db4b8d KS |
150 | dbg("exec of child failed"); |
151 | exit(1); | |
90c210eb KS |
152 | break; |
153 | case -1: | |
33db4b8d | 154 | dbg("fork of child failed"); |
2f6cbd19 | 155 | run_queue_delete(msg); |
f27125f9 | 156 | /* note: we never managed to run, so we had no impact on |
157 | * running_with_devpath(), so don't bother setting run_exec_q | |
158 | */ | |
2f6cbd19 | 159 | break; |
90c210eb | 160 | default: |
2f6cbd19 KS |
161 | /* get SIGCHLD in main loop */ |
162 | dbg("==> exec seq %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath); | |
163 | msg->pid = pid; | |
90c210eb | 164 | } |
7fafc032 KS |
165 | } |
166 | ||
53921bfa KS |
167 | /* returns already running task with devpath */ |
168 | static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg) | |
7fafc032 | 169 | { |
53921bfa | 170 | struct hotplug_msg *loop_msg; |
2f6cbd19 | 171 | list_for_each_entry(loop_msg, &running_list, list) |
53921bfa KS |
172 | if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0) |
173 | return loop_msg; | |
174 | return NULL; | |
7fafc032 KS |
175 | } |
176 | ||
2f6cbd19 KS |
177 | /* exec queue management routine executes the events and delays events for the same devpath */ |
178 | static void exec_queue_manager() | |
7fafc032 | 179 | { |
53921bfa KS |
180 | struct hotplug_msg *loop_msg; |
181 | struct hotplug_msg *tmp_msg; | |
a695feae | 182 | struct hotplug_msg *msg; |
53921bfa | 183 | |
2f6cbd19 KS |
184 | list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) { |
185 | msg = running_with_devpath(loop_msg); | |
186 | if (!msg) { | |
187 | /* move event to run list */ | |
188 | list_move_tail(&loop_msg->list, &running_list); | |
189 | udev_run(loop_msg); | |
190 | dbg("moved seq %d to running list", loop_msg->seqnum); | |
191 | } else { | |
192 | dbg("delay seq %d, cause seq %d already working on '%s'", | |
193 | loop_msg->seqnum, msg->seqnum, msg->devpath); | |
53921bfa | 194 | } |
53921bfa KS |
195 | } |
196 | } | |
197 | ||
2f6cbd19 | 198 | static void msg_move_exec(struct hotplug_msg *msg) |
86590cd5 | 199 | { |
2f6cbd19 | 200 | list_move_tail(&msg->list, &exec_list); |
f27125f9 | 201 | run_exec_q = 1; |
2f6cbd19 KS |
202 | expected_seqnum = msg->seqnum+1; |
203 | dbg("moved seq %d to exec, next expected is %d", | |
204 | msg->seqnum, expected_seqnum); | |
86590cd5 KS |
205 | } |
206 | ||
2f6cbd19 KS |
207 | /* msg queue management routine handles the timeouts and dispatches the events */ |
208 | static void msg_queue_manager() | |
53921bfa KS |
209 | { |
210 | struct hotplug_msg *loop_msg; | |
a695feae | 211 | struct hotplug_msg *tmp_msg; |
e5a2989e KS |
212 | struct sysinfo info; |
213 | long msg_age = 0; | |
a695feae | 214 | |
2f6cbd19 | 215 | dbg("msg queue manager, next expected is %d", expected_seqnum); |
a695feae | 216 | recheck: |
2f6cbd19 KS |
217 | list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) { |
218 | /* move event with expected sequence to the exec list */ | |
219 | if (loop_msg->seqnum == expected_seqnum) { | |
220 | msg_move_exec(loop_msg); | |
221 | continue; | |
a695feae | 222 | } |
35b7d88c | 223 | |
2f6cbd19 | 224 | /* move event with expired timeout to the exec list */ |
e5a2989e KS |
225 | sysinfo(&info); |
226 | msg_age = info.uptime - loop_msg->queue_time; | |
227 | dbg("seq %d is %li seconds old", loop_msg->seqnum, msg_age); | |
2f6cbd19 KS |
228 | if (msg_age > EVENT_TIMEOUT_SEC-1) { |
229 | msg_move_exec(loop_msg); | |
230 | goto recheck; | |
53921bfa | 231 | } else { |
2f6cbd19 | 232 | break; |
53921bfa | 233 | } |
2f6cbd19 KS |
234 | } |
235 | ||
236 | msg_dump_queue(); | |
237 | ||
e5a2989e | 238 | /* set timeout for remaining queued events */ |
2f6cbd19 | 239 | if (list_empty(&msg_list) == 0) { |
2f6cbd19 | 240 | struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}}; |
e5a2989e | 241 | dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC - msg_age); |
2f6cbd19 | 242 | setitimer(ITIMER_REAL, &itv, 0); |
7fafc032 | 243 | } |
7fafc032 KS |
244 | } |
245 | ||
2f6cbd19 KS |
246 | /* receive the msg, do some basic sanity checks, and queue it */ |
247 | static void handle_msg(int sock) | |
7fafc032 | 248 | { |
53921bfa KS |
249 | struct hotplug_msg *msg; |
250 | int retval; | |
0028653c KS |
251 | struct msghdr smsg; |
252 | struct cmsghdr *cmsg; | |
253 | struct iovec iov; | |
254 | struct ucred *cred; | |
255 | char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; | |
a695feae | 256 | |
53921bfa KS |
257 | msg = msg_create(); |
258 | if (msg == NULL) { | |
259 | dbg("unable to store message"); | |
2f6cbd19 | 260 | return; |
7fafc032 | 261 | } |
7fafc032 | 262 | |
0028653c KS |
263 | iov.iov_base = msg; |
264 | iov.iov_len = sizeof(struct hotplug_msg); | |
265 | ||
266 | memset(&smsg, 0x00, sizeof(struct msghdr)); | |
267 | smsg.msg_iov = &iov; | |
268 | smsg.msg_iovlen = 1; | |
269 | smsg.msg_control = cred_msg; | |
270 | smsg.msg_controllen = sizeof(cred_msg); | |
271 | ||
272 | retval = recvmsg(sock, &smsg, 0); | |
53921bfa | 273 | if (retval < 0) { |
2f6cbd19 KS |
274 | if (errno != EINTR) |
275 | dbg("unable to receive message"); | |
276 | return; | |
53921bfa | 277 | } |
0028653c KS |
278 | cmsg = CMSG_FIRSTHDR(&smsg); |
279 | cred = (struct ucred *) CMSG_DATA(cmsg); | |
280 | ||
7b1cbec9 KS |
281 | if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { |
282 | dbg("no sender credentials received, message ignored"); | |
283 | goto skip; | |
284 | } | |
285 | ||
0028653c KS |
286 | if (cred->uid != 0) { |
287 | dbg("sender uid=%i, message ignored", cred->uid); | |
7b1cbec9 | 288 | goto skip; |
0028653c KS |
289 | } |
290 | ||
53921bfa KS |
291 | if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) { |
292 | dbg("message magic '%s' doesn't match, ignore it", msg->magic); | |
7b1cbec9 | 293 | goto skip; |
53921bfa | 294 | } |
a695feae | 295 | |
86590cd5 | 296 | /* if no seqnum is given, we move straight to exec queue */ |
2f6cbd19 | 297 | if (msg->seqnum == -1) { |
86590cd5 | 298 | list_add(&msg->list, &exec_list); |
f27125f9 | 299 | run_exec_q = 1; |
86590cd5 | 300 | } else { |
86590cd5 | 301 | msg_queue_insert(msg); |
86590cd5 | 302 | } |
7b1cbec9 KS |
303 | return; |
304 | ||
305 | skip: | |
306 | free(msg); | |
307 | return; | |
a695feae | 308 | } |
1c5c245e | 309 | |
53921bfa | 310 | static void sig_handler(int signum) |
7fafc032 | 311 | { |
f27125f9 | 312 | int rc; |
53921bfa KS |
313 | switch (signum) { |
314 | case SIGINT: | |
315 | case SIGTERM: | |
53921bfa KS |
316 | exit(20 + signum); |
317 | break; | |
2f6cbd19 | 318 | case SIGALRM: |
f27125f9 | 319 | /* set flag, then write to pipe if needed */ |
320 | run_msg_q = 1; | |
321 | goto do_write; | |
2f6cbd19 KS |
322 | break; |
323 | case SIGCHLD: | |
f27125f9 | 324 | /* set flag, then write to pipe if needed */ |
2f6cbd19 | 325 | children_waiting = 1; |
f27125f9 | 326 | goto do_write; |
2f6cbd19 | 327 | break; |
53921bfa KS |
328 | default: |
329 | dbg("unhandled signal"); | |
f27125f9 | 330 | return; |
331 | } | |
332 | ||
333 | do_write: | |
334 | /* if pipe is empty, write to pipe to force select to return | |
335 | * immediately when it gets called | |
336 | */ | |
337 | if (!sig_flag) { | |
338 | rc = write(pipefds[1],&signum,sizeof(signum)); | |
339 | if (rc < 0) | |
340 | dbg("unable to write to pipe"); | |
341 | else | |
342 | sig_flag = 1; | |
7fafc032 | 343 | } |
33db4b8d | 344 | } |
7fafc032 | 345 | |
2f6cbd19 KS |
346 | static void udev_done(int pid) |
347 | { | |
348 | /* find msg associated with pid and delete it */ | |
349 | struct hotplug_msg *msg; | |
350 | ||
351 | list_for_each_entry(msg, &running_list, list) { | |
352 | if (msg->pid == pid) { | |
353 | dbg("<== exec seq %d came back", msg->seqnum); | |
354 | run_queue_delete(msg); | |
f27125f9 | 355 | |
356 | /* we want to run the exec queue manager since there may | |
357 | * be events waiting with the devpath of the one that | |
358 | * just finished | |
359 | */ | |
360 | run_exec_q = 1; | |
2f6cbd19 KS |
361 | return; |
362 | } | |
363 | } | |
364 | } | |
365 | ||
f27125f9 | 366 | static void reap_kids() |
367 | { | |
368 | /* reap all dead children */ | |
369 | while(1) { | |
370 | int pid = waitpid(-1, 0, WNOHANG); | |
371 | if ((pid == -1) || (pid == 0)) | |
372 | break; | |
373 | udev_done(pid); | |
374 | } | |
375 | } | |
376 | ||
377 | /* just read everything from the pipe and clear the flag, | |
378 | * the useful flags were set in the signal handler | |
379 | */ | |
380 | static void user_sighandler() | |
381 | { | |
382 | int sig; | |
383 | while(1) { | |
384 | int rc = read(pipefds[0],&sig,sizeof(sig)); | |
385 | if (rc < 0) | |
386 | break; | |
387 | ||
388 | sig_flag = 0; | |
389 | } | |
390 | } | |
391 | ||
392 | ||
33db4b8d KS |
393 | int main(int argc, char *argv[]) |
394 | { | |
f27125f9 | 395 | int ssock, maxsockplus; |
53921bfa | 396 | struct sockaddr_un saddr; |
1dadabd7 | 397 | socklen_t addrlen; |
53921bfa | 398 | int retval; |
0028653c | 399 | const int on = 1; |
f8911dbb | 400 | struct sigaction act; |
f27125f9 | 401 | fd_set readfds; |
53921bfa | 402 | |
95a6f4c8 | 403 | init_logging("udevd"); |
896e5aa9 | 404 | dbg("version %s", UDEV_VERSION); |
95a6f4c8 | 405 | |
7b1cbec9 KS |
406 | if (getuid() != 0) { |
407 | dbg("need to be root, exit"); | |
408 | exit(1); | |
409 | } | |
e5a2989e | 410 | |
f27125f9 | 411 | /* setup signal handler pipe */ |
e5a2989e KS |
412 | retval = pipe(pipefds); |
413 | if (retval < 0) { | |
414 | dbg("error getting pipes: %s", strerror(errno)); | |
415 | exit(1); | |
416 | } | |
417 | ||
418 | retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK); | |
419 | if (retval < 0) { | |
420 | dbg("error fcntl on read pipe: %s", strerror(errno)); | |
421 | exit(1); | |
422 | } | |
423 | ||
424 | retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK); | |
425 | if (retval < 0) { | |
426 | dbg("error fcntl on write pipe: %s", strerror(errno)); | |
427 | exit(1); | |
428 | } | |
f27125f9 | 429 | |
430 | /* set signal handlers */ | |
f8911dbb | 431 | act.sa_handler = sig_handler; |
f27125f9 | 432 | sigemptyset(&act.sa_mask); |
f8911dbb KS |
433 | act.sa_flags = SA_RESTART; |
434 | sigaction(SIGINT, &act, NULL); | |
435 | sigaction(SIGTERM, &act, NULL); | |
f8911dbb KS |
436 | sigaction(SIGALRM, &act, NULL); |
437 | sigaction(SIGCHLD, &act, NULL); | |
7fafc032 | 438 | |
53921bfa KS |
439 | memset(&saddr, 0x00, sizeof(saddr)); |
440 | saddr.sun_family = AF_LOCAL; | |
872344c4 KS |
441 | /* use abstract namespace for socket path */ |
442 | strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH); | |
1dadabd7 | 443 | addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1; |
53921bfa | 444 | |
2f6cbd19 | 445 | ssock = socket(AF_LOCAL, SOCK_DGRAM, 0); |
53921bfa | 446 | if (ssock == -1) { |
7b1cbec9 | 447 | dbg("error getting socket, exit"); |
53921bfa KS |
448 | exit(1); |
449 | } | |
450 | ||
2f6cbd19 | 451 | /* the bind takes care of ensuring only one copy running */ |
f8911dbb | 452 | retval = bind(ssock, (struct sockaddr *) &saddr, addrlen); |
53921bfa | 453 | if (retval < 0) { |
7b1cbec9 | 454 | dbg("bind failed, exit"); |
53921bfa KS |
455 | goto exit; |
456 | } | |
457 | ||
0028653c KS |
458 | /* enable receiving of the sender credentials */ |
459 | setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); | |
460 | ||
e5a2989e KS |
461 | FD_ZERO(&readfds); |
462 | FD_SET(ssock, &readfds); | |
463 | FD_SET(pipefds[0], &readfds); | |
f27125f9 | 464 | maxsockplus = ssock+1; |
2f6cbd19 | 465 | while (1) { |
f27125f9 | 466 | fd_set workreadfds = readfds; |
467 | retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL); | |
e5a2989e | 468 | |
f27125f9 | 469 | if (retval < 0) { |
e5a2989e KS |
470 | if (errno != EINTR) |
471 | dbg("error in select: %s", strerror(errno)); | |
f27125f9 | 472 | continue; |
2f6cbd19 | 473 | } |
e5a2989e | 474 | |
f27125f9 | 475 | if (FD_ISSET(ssock, &workreadfds)) |
476 | handle_msg(ssock); | |
e5a2989e | 477 | |
f27125f9 | 478 | if (FD_ISSET(pipefds[0], &workreadfds)) |
479 | user_sighandler(); | |
e5a2989e | 480 | |
f27125f9 | 481 | if (children_waiting) { |
2f6cbd19 | 482 | children_waiting = 0; |
f27125f9 | 483 | reap_kids(); |
484 | } | |
e5a2989e | 485 | |
f27125f9 | 486 | if (run_msg_q) { |
487 | run_msg_q = 0; | |
488 | msg_queue_manager(); | |
489 | } | |
e5a2989e | 490 | |
f27125f9 | 491 | if (run_exec_q) { |
f27125f9 | 492 | /* this is tricky. exec_queue_manager() loops over exec_list, and |
493 | * calls running_with_devpath(), which loops over running_list. This gives | |
494 | * O(N*M), which can get *nasty*. Clean up running_list before | |
495 | * calling exec_queue_manager(). | |
496 | */ | |
f27125f9 | 497 | if (children_waiting) { |
498 | children_waiting = 0; | |
499 | reap_kids(); | |
2f6cbd19 | 500 | } |
f27125f9 | 501 | |
502 | run_exec_q = 0; | |
503 | exec_queue_manager(); | |
53921bfa | 504 | } |
53921bfa KS |
505 | } |
506 | exit: | |
507 | close(ssock); | |
53921bfa | 508 | exit(1); |
7fafc032 | 509 | } |