xref: /freebsd/sys/kern/kern_shutdown.c (revision eacee0ff7ec955b32e09515246bd97b6edcd2b0f)
1 /*-
2  * Copyright (c) 1986, 1988, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)kern_shutdown.c	8.3 (Berkeley) 1/21/94
39  * $FreeBSD$
40  */
41 
42 #include "opt_ddb.h"
43 #include "opt_hw_wdog.h"
44 #include "opt_panic.h"
45 #include "opt_show_busybufs.h"
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/bio.h>
50 #include <sys/buf.h>
51 #include <sys/conf.h>
52 #include <sys/cons.h>
53 #include <sys/disklabel.h>
54 #include <sys/eventhandler.h>
55 #include <sys/kernel.h>
56 #include <sys/kthread.h>
57 #include <sys/malloc.h>
58 #include <sys/mount.h>
59 #include <sys/proc.h>
60 #include <sys/reboot.h>
61 #include <sys/resourcevar.h>
62 #include <sys/smp.h>		/* smp_active */
63 #include <sys/sysctl.h>
64 #include <sys/sysproto.h>
65 #include <sys/vnode.h>
66 
67 #include <machine/pcb.h>
68 #include <machine/md_var.h>
69 
70 #include <sys/signalvar.h>
71 #ifdef DDB
72 #include <ddb/ddb.h>
73 #endif
74 
75 #ifndef PANIC_REBOOT_WAIT_TIME
76 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
77 #endif
78 
79 /*
80  * Note that stdarg.h and the ANSI style va_start macro is used for both
81  * ANSI and traditional C compilers.
82  */
83 #include <machine/stdarg.h>
84 
85 #ifdef DDB
86 #ifdef DDB_UNATTENDED
87 int debugger_on_panic = 0;
88 #else
89 int debugger_on_panic = 1;
90 #endif
91 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW,
92 	&debugger_on_panic, 0, "Run debugger on kernel panic");
93 #endif
94 
95 int sync_on_panic = 1;
96 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW,
97 	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
98 
99 SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
100 
101 #ifdef	HW_WDOG
102 /*
103  * If there is a hardware watchdog, point this at the function needed to
104  * hold it off.
105  * It's needed when the kernel needs to do some lengthy operations.
106  * e.g. in wd.c when dumping core.. It's most annoying to have
107  * your precious core-dump only half written because the wdog kicked in.
108  */
109 watchdog_tickle_fn wdog_tickler = NULL;
110 #endif	/* HW_WDOG */
111 
112 /*
113  * Variable panicstr contains argument to first call to panic; used as flag
114  * to indicate that the kernel has already called panic.
115  */
116 const char *panicstr;
117 
118 int dumping;				 /* system is dumping */
119 
120 static void boot(int) __dead2;
121 static void dumpsys(void);
122 static void poweroff_wait(void *, int);
123 static void shutdown_halt(void *junk, int howto);
124 static void shutdown_panic(void *junk, int howto);
125 static void shutdown_reset(void *junk, int howto);
126 
127 /* register various local shutdown events */
128 static void
129 shutdown_conf(void *unused)
130 {
131 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL, SHUTDOWN_PRI_FIRST);
132 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL, SHUTDOWN_PRI_LAST + 100);
133 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL, SHUTDOWN_PRI_LAST + 100);
134 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL, SHUTDOWN_PRI_LAST + 200);
135 }
136 
137 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL)
138 
139 /*
140  * The system call that results in a reboot
141  *
142  * MPSAFE
143  */
144 /* ARGSUSED */
145 int
146 reboot(struct thread *td, struct reboot_args *uap)
147 {
148 	int error;
149 
150 	mtx_lock(&Giant);
151 	if ((error = suser_td(td)) == 0)
152 		boot(uap->opt);
153 	mtx_unlock(&Giant);
154 	return (error);
155 }
156 
157 /*
158  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
159  */
160 static int shutdown_howto = 0;
161 
162 void
163 shutdown_nice(int howto)
164 {
165 	shutdown_howto = howto;
166 
167 	/* Send a signal to init(8) and have it shutdown the world */
168 	if (initproc != NULL) {
169 		PROC_LOCK(initproc);
170 		psignal(initproc, SIGINT);
171 		PROC_UNLOCK(initproc);
172 	} else {
173 		/* No init(8) running, so simply reboot */
174 		boot(RB_NOSYNC);
175 	}
176 	return;
177 }
178 static int	waittime = -1;
179 static struct pcb dumppcb;
180 
181 static void
182 print_uptime(void)
183 {
184 	int f;
185 	struct timespec ts;
186 
187 	getnanouptime(&ts);
188 	printf("Uptime: ");
189 	f = 0;
190 	if (ts.tv_sec >= 86400) {
191 		printf("%ldd", (long)ts.tv_sec / 86400);
192 		ts.tv_sec %= 86400;
193 		f = 1;
194 	}
195 	if (f || ts.tv_sec >= 3600) {
196 		printf("%ldh", (long)ts.tv_sec / 3600);
197 		ts.tv_sec %= 3600;
198 		f = 1;
199 	}
200 	if (f || ts.tv_sec >= 60) {
201 		printf("%ldm", (long)ts.tv_sec / 60);
202 		ts.tv_sec %= 60;
203 		f = 1;
204 	}
205 	printf("%lds\n", (long)ts.tv_sec);
206 }
207 
208 /*
209  *  Go through the rigmarole of shutting down..
210  * this used to be in machdep.c but I'll be dammned if I could see
211  * anything machine dependant in it.
212  */
213 static void
214 boot(int howto)
215 {
216 
217 	/* collect extra flags that shutdown_nice might have set */
218 	howto |= shutdown_howto;
219 
220 #ifdef DDB
221 	/* We are out of the debugger now. */
222 	db_active = 0;
223 #endif
224 
225 #ifdef SMP
226 	if (smp_active)
227 		printf("boot() called on cpu#%d\n", PCPU_GET(cpuid));
228 #endif
229 	/*
230 	 * Do any callouts that should be done BEFORE syncing the filesystems.
231 	 */
232 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
233 
234 	/*
235 	 * Now sync filesystems
236 	 */
237 	if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
238 		register struct buf *bp;
239 		int iter, nbusy, pbusy;
240 		int subiter;
241 
242 		waittime = 0;
243 		printf("\nsyncing disks... ");
244 
245 		sync(&thread0, NULL);
246 
247 		/*
248 		 * With soft updates, some buffers that are
249 		 * written will be remarked as dirty until other
250 		 * buffers are written.
251 		 */
252 		for (iter = pbusy = 0; iter < 20; iter++) {
253 			nbusy = 0;
254 			for (bp = &buf[nbuf]; --bp >= buf; ) {
255 				if ((bp->b_flags & B_INVAL) == 0 &&
256 				    BUF_REFCNT(bp) > 0) {
257 					nbusy++;
258 				} else if ((bp->b_flags & (B_DELWRI | B_INVAL))
259 						== B_DELWRI) {
260 					/* bawrite(bp);*/
261 					nbusy++;
262 				}
263 			}
264 			if (nbusy == 0)
265 				break;
266 			printf("%d ", nbusy);
267 			if (nbusy < pbusy)
268 				iter = 0;
269 			pbusy = nbusy;
270 			sync(&thread0, NULL);
271  			if (curthread != NULL) {
272 				DROP_GIANT();
273    				for (subiter = 0; subiter < 50 * iter; subiter++) {
274      					mtx_lock_spin(&sched_lock);
275 					setrunqueue(curthread);
276 					curthread->td_proc->p_stats->p_ru.ru_nvcsw++;
277      					mi_switch(); /* Allow interrupt threads to run */
278      					mtx_unlock_spin(&sched_lock);
279      					DELAY(1000);
280    				}
281 				PICKUP_GIANT();
282  			} else
283 			DELAY(50000 * iter);
284 		}
285 		printf("\n");
286 		/*
287 		 * Count only busy local buffers to prevent forcing
288 		 * a fsck if we're just a client of a wedged NFS server
289 		 */
290 		nbusy = 0;
291 		for (bp = &buf[nbuf]; --bp >= buf; ) {
292 			if (((bp->b_flags&B_INVAL) == 0 && BUF_REFCNT(bp)) ||
293 			    ((bp->b_flags & (B_DELWRI|B_INVAL)) == B_DELWRI)) {
294 				if (bp->b_dev == NODEV) {
295 					TAILQ_REMOVE(&mountlist,
296 					    bp->b_vp->v_mount, mnt_list);
297 					continue;
298 				}
299 				nbusy++;
300 #if defined(SHOW_BUSYBUFS) || defined(DIAGNOSTIC)
301 				printf(
302 			    "%d: dev:%s, flags:%08lx, blkno:%ld, lblkno:%ld\n",
303 				    nbusy, devtoname(bp->b_dev),
304 				    bp->b_flags, (long)bp->b_blkno,
305 				    (long)bp->b_lblkno);
306 #endif
307 			}
308 		}
309 		if (nbusy) {
310 			/*
311 			 * Failed to sync all blocks. Indicate this and don't
312 			 * unmount filesystems (thus forcing an fsck on reboot).
313 			 */
314 			printf("giving up on %d buffers\n", nbusy);
315 			DELAY(5000000);	/* 5 seconds */
316 		} else {
317 			printf("done\n");
318 			/*
319 			 * Unmount filesystems
320 			 */
321 			if (panicstr == 0)
322 				vfs_unmountall();
323 		}
324 		DELAY(100000);		/* wait for console output to finish */
325 	}
326 
327 	print_uptime();
328 
329 	/*
330 	 * Ok, now do things that assume all filesystem activity has
331 	 * been completed.
332 	 */
333 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
334 	splhigh();
335 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold)
336 		dumpsys();
337 
338 	/* Now that we're going to really halt the system... */
339 	EVENTHANDLER_INVOKE(shutdown_final, howto);
340 
341 	for(;;) ;	/* safety against shutdown_reset not working */
342 	/* NOTREACHED */
343 }
344 
345 /*
346  * If the shutdown was a clean halt, behave accordingly.
347  */
348 static void
349 shutdown_halt(void *junk, int howto)
350 {
351 	if (howto & RB_HALT) {
352 		printf("\n");
353 		printf("The operating system has halted.\n");
354 		printf("Please press any key to reboot.\n\n");
355 		switch (cngetc()) {
356 		case -1:		/* No console, just die */
357 			cpu_halt();
358 			/* NOTREACHED */
359 		default:
360 			howto &= ~RB_HALT;
361 			break;
362 		}
363 	}
364 }
365 
366 /*
367  * Check to see if the system paniced, pause and then reboot
368  * according to the specified delay.
369  */
370 static void
371 shutdown_panic(void *junk, int howto)
372 {
373 	int loop;
374 
375 	if (howto & RB_DUMP) {
376 		if (PANIC_REBOOT_WAIT_TIME != 0) {
377 			if (PANIC_REBOOT_WAIT_TIME != -1) {
378 				printf("Automatic reboot in %d seconds - "
379 				       "press a key on the console to abort\n",
380 					PANIC_REBOOT_WAIT_TIME);
381 				for (loop = PANIC_REBOOT_WAIT_TIME * 10;
382 				     loop > 0; --loop) {
383 					DELAY(1000 * 100); /* 1/10th second */
384 					/* Did user type a key? */
385 					if (cncheckc() != -1)
386 						break;
387 				}
388 				if (!loop)
389 					return;
390 			}
391 		} else { /* zero time specified - reboot NOW */
392 			return;
393 		}
394 		printf("--> Press a key on the console to reboot,\n");
395 		printf("--> or switch off the system now.\n");
396 		cngetc();
397 	}
398 }
399 
400 /*
401  * Everything done, now reset
402  */
403 static void
404 shutdown_reset(void *junk, int howto)
405 {
406 	printf("Rebooting...\n");
407 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
408 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
409 	cpu_reset();
410 	/* NOTREACHED */ /* assuming reset worked */
411 }
412 
413 /*
414  * Magic number for savecore
415  *
416  * exported (symorder) and used at least by savecore(8)
417  *
418  */
419 static u_long const	dumpmag = 0x8fca0101UL;
420 
421 static int	dumpsize = 0;		/* also for savecore */
422 
423 static int	dodump = 1;
424 
425 SYSCTL_INT(_machdep, OID_AUTO, do_dump, CTLFLAG_RW, &dodump, 0,
426     "Try to perform coredump on kernel panic");
427 
428 static int
429 setdumpdev(dev_t dev)
430 {
431 	int psize;
432 	long newdumplo;
433 
434 	if (dev == NODEV) {
435 		dumpdev = dev;
436 		return (0);
437 	}
438 	if (devsw(dev) == NULL)
439 		return (ENXIO);		/* XXX is this right? */
440 	if (devsw(dev)->d_psize == NULL)
441 		return (ENXIO);		/* XXX should be ENODEV ? */
442 	psize = devsw(dev)->d_psize(dev);
443 	if (psize == -1)
444 		return (ENXIO);		/* XXX should be ENODEV ? */
445 	/*
446 	 * XXX should clean up checking in dumpsys() to be more like this.
447 	 */
448 	newdumplo = psize - Maxmem * (PAGE_SIZE / DEV_BSIZE);
449 	if (newdumplo <= LABELSECTOR)
450 		return (ENOSPC);
451 	dumpdev = dev;
452 	dumplo = newdumplo;
453 	return (0);
454 }
455 
456 
457 /* ARGSUSED */
458 static void
459 dump_conf(void *dummy)
460 {
461 	char *path;
462 	dev_t dev;
463 
464 	path = malloc(MNAMELEN, M_TEMP, M_WAITOK);
465 	if (TUNABLE_STR_FETCH("dumpdev", path, MNAMELEN) != 0) {
466 		dev = getdiskbyname(path);
467 		if (dev != NODEV)
468 			dumpdev = dev;
469 	}
470 	free(path, M_TEMP);
471 	if (setdumpdev(dumpdev) != 0)
472 		dumpdev = NODEV;
473 }
474 
475 SYSINIT(dump_conf, SI_SUB_DUMP_CONF, SI_ORDER_FIRST, dump_conf, NULL)
476 
477 static int
478 sysctl_kern_dumpdev(SYSCTL_HANDLER_ARGS)
479 {
480 	int error;
481 	udev_t ndumpdev;
482 
483 	ndumpdev = dev2udev(dumpdev);
484 	error = sysctl_handle_opaque(oidp, &ndumpdev, sizeof ndumpdev, req);
485 	if (error == 0 && req->newptr != NULL)
486 		error = setdumpdev(udev2dev(ndumpdev, 0));
487 	return (error);
488 }
489 
490 SYSCTL_PROC(_kern, KERN_DUMPDEV, dumpdev, CTLTYPE_OPAQUE|CTLFLAG_RW,
491 	0, sizeof dumpdev, sysctl_kern_dumpdev, "T,dev_t", "");
492 
493 /*
494  * Doadump comes here after turning off memory management and
495  * getting on the dump stack, either when called above, or by
496  * the auto-restart code.
497  */
498 static void
499 dumpsys(void)
500 {
501 	int	error;
502 
503 	savectx(&dumppcb);
504 	if (!dodump)
505 		return;
506 	if (dumpdev == NODEV)
507 		return;
508 	if (!(devsw(dumpdev)))
509 		return;
510 	if (!(devsw(dumpdev)->d_dump))
511 		return;
512 	if (dumping++) {
513 		dumping--;
514 		printf("Dump already in progress, bailing...\n");
515 		return;
516 	}
517 	dumpsize = Maxmem;
518 	printf("\ndumping to dev %s, offset %ld\n", devtoname(dumpdev), dumplo);
519 	printf("dump ");
520 	error = (*devsw(dumpdev)->d_dump)(dumpdev);
521 	dumping--;
522 	if (error == 0) {
523 		printf("succeeded\n");
524 		return;
525 	}
526 	printf("failed, reason: ");
527 	switch (error) {
528 	case ENODEV:
529 		printf("device doesn't support a dump routine\n");
530 		break;
531 
532 	case ENXIO:
533 		printf("device bad\n");
534 		break;
535 
536 	case EFAULT:
537 		printf("device not ready\n");
538 		break;
539 
540 	case EINVAL:
541 		printf("area improper\n");
542 		break;
543 
544 	case EIO:
545 		printf("i/o error\n");
546 		break;
547 
548 	case EINTR:
549 		printf("aborted from console\n");
550 		break;
551 
552 	default:
553 		printf("unknown, error = %d\n", error);
554 		break;
555 	}
556 }
557 
558 int
559 dumpstatus(vm_offset_t addr, off_t count)
560 {
561 	int c;
562 
563 	if (addr % (1024 * 1024) == 0) {
564 #ifdef HW_WDOG
565 		if (wdog_tickler)
566 			(*wdog_tickler)();
567 #endif
568 		printf("%ld ", (long)(count / (1024 * 1024)));
569 	}
570 
571 	if ((c = cncheckc()) == 0x03)
572 		return -1;
573 	else if (c != -1)
574 		printf("[CTRL-C to abort] ");
575 
576 	return 0;
577 }
578 
579 #ifdef SMP
580 static u_int panic_cpu = NOCPU;
581 #endif
582 
583 /*
584  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
585  * and then reboots.  If we are called twice, then we avoid trying to sync
586  * the disks as this often leads to recursive panics.
587  *
588  * MPSAFE
589  */
590 void
591 panic(const char *fmt, ...)
592 {
593 	int bootopt;
594 	va_list ap;
595 	static char buf[256];
596 
597 #ifdef SMP
598 	/*
599 	 * We don't want multiple CPU's to panic at the same time, so we
600 	 * use panic_cpu as a simple spinlock.  We have to keep checking
601 	 * panic_cpu if we are spinning in case the panic on the first
602 	 * CPU is canceled.
603 	 */
604 	if (panic_cpu != PCPU_GET(cpuid))
605 		while (atomic_cmpset_int(&panic_cpu, NOCPU,
606 		    PCPU_GET(cpuid)) == 0)
607 			while (panic_cpu != NOCPU)
608 				; /* nothing */
609 #endif
610 
611 	bootopt = RB_AUTOBOOT | RB_DUMP;
612 	if (panicstr)
613 		bootopt |= RB_NOSYNC;
614 	else
615 		panicstr = fmt;
616 
617 	va_start(ap, fmt);
618 	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
619 	if (panicstr == fmt)
620 		panicstr = buf;
621 	va_end(ap);
622 	printf("panic: %s\n", buf);
623 #ifdef SMP
624 	/* two separate prints in case of an unmapped page and trap */
625 	printf("cpuid = %d; ", PCPU_GET(cpuid));
626 #ifdef APIC_IO
627 	printf("lapic.id = %08x\n", lapic.id);
628 #endif
629 #endif
630 
631 #if defined(DDB)
632 	if (debugger_on_panic)
633 		Debugger ("panic");
634 #ifdef RESTARTABLE_PANICS
635 	/* See if the user aborted the panic, in which case we continue. */
636 	if (panicstr == NULL) {
637 #ifdef SMP
638 		atomic_store_rel_int(&panic_cpu, NOCPU);
639 #endif
640 		return;
641 	}
642 #endif
643 #endif
644 	if (!sync_on_panic)
645 		bootopt |= RB_NOSYNC;
646 	boot(bootopt);
647 }
648 
649 /*
650  * Support for poweroff delay.
651  */
652 #ifndef POWEROFF_DELAY
653 # define POWEROFF_DELAY 5000
654 #endif
655 static int poweroff_delay = POWEROFF_DELAY;
656 
657 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
658 	&poweroff_delay, 0, "");
659 
660 static void
661 poweroff_wait(void *junk, int howto)
662 {
663 	if(!(howto & RB_POWEROFF) || poweroff_delay <= 0)
664 		return;
665 	DELAY(poweroff_delay * 1000);
666 }
667 
668 /*
669  * Some system processes (e.g. syncer) need to be stopped at appropriate
670  * points in their main loops prior to a system shutdown, so that they
671  * won't interfere with the shutdown process (e.g. by holding a disk buf
672  * to cause sync to fail).  For each of these system processes, register
673  * shutdown_kproc() as a handler for one of shutdown events.
674  */
675 static int kproc_shutdown_wait = 60;
676 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
677     &kproc_shutdown_wait, 0, "");
678 
679 void
680 kproc_shutdown(void *arg, int howto)
681 {
682 	struct proc *p;
683 	int error;
684 
685 	if (panicstr)
686 		return;
687 
688 	p = (struct proc *)arg;
689 	printf("Waiting (max %d seconds) for system process `%s' to stop...",
690 	    kproc_shutdown_wait, p->p_comm);
691 	error = kthread_suspend(p, kproc_shutdown_wait * hz);
692 
693 	if (error == EWOULDBLOCK)
694 		printf("timed out\n");
695 	else
696 		printf("stopped\n");
697 }
698