xref: /netbsd-src/sbin/savecore/savecore.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: savecore.c,v 1.71 2007/11/12 16:04:55 pooka Exp $	*/
2 
3 /*-
4  * Copyright (c) 1986, 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1986, 1992, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n");
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)savecore.c	8.5 (Berkeley) 4/28/95";
41 #else
42 __RCSID("$NetBSD: savecore.c,v 1.71 2007/11/12 16:04:55 pooka Exp $");
43 #endif
44 #endif /* not lint */
45 
46 #include <sys/param.h>
47 #include <sys/mount.h>
48 #include <sys/msgbuf.h>
49 #include <sys/syslog.h>
50 #include <sys/time.h>
51 
52 #include <dirent.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <nlist.h>
56 #include <paths.h>
57 #include <stddef.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <time.h>
62 #include <tzfile.h>
63 #include <unistd.h>
64 #include <util.h>
65 #include <limits.h>
66 #include <kvm.h>
67 
68 extern FILE *zopen(const char *fname, const char *mode);
69 
70 #define	KREAD(kd, addr, p)\
71 	(kvm_read(kd, addr, (char *)(p), sizeof(*(p))) != sizeof(*(p)))
72 
73 struct nlist current_nl[] = {	/* Namelist for currently running system. */
74 #define	X_DUMPDEV	0
75 	{ .n_name = "_dumpdev" },
76 #define	X_DUMPLO	1
77 	{ .n_name = "_dumplo" },
78 #define	X_TIME_SECOND	2
79 	{ .n_name = "_time_second" },
80 #define X_TIME		3
81 	{ .n_name = "_time" },
82 #define	X_DUMPSIZE	4
83 	{ .n_name = "_dumpsize" },
84 #define	X_VERSION	5
85 	{ .n_name = "_version" },
86 #define	X_DUMPMAG	6
87 	{ .n_name = "_dumpmag" },
88 #define	X_PANICSTR	7
89 	{ .n_name = "_panicstr" },
90 #define	X_PANICSTART	8
91 	{ .n_name = "_panicstart" },
92 #define	X_PANICEND	9
93 	{ .n_name = "_panicend" },
94 #define	X_MSGBUF	10
95 	{ .n_name = "_msgbufp" },
96 	{ .n_name = NULL },
97 };
98 int cursyms[] = { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
99 int dumpsyms[] = { X_TIME_SECOND, X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG,
100     -1 };
101 
102 struct nlist dump_nl[] = {	/* Name list for dumped system. */
103 	{ .n_name = "_dumpdev" },	/* Entries MUST be the same as */
104 	{ .n_name = "_dumplo" },	/*	those in current_nl[].  */
105 	{ .n_name = "_time_second" },
106 	{ .n_name = "_time" },
107 	{ .n_name = "_dumpsize" },
108 	{ .n_name = "_version" },
109 	{ .n_name = "_dumpmag" },
110 	{ .n_name = "_panicstr" },
111 	{ .n_name = "_panicstart" },
112 	{ .n_name = "_panicend" },
113 	{ .n_name = "_msgbufp" },
114 	{ .n_name = NULL },
115 };
116 
117 /* Types match kernel declarations. */
118 off_t	dumplo;				/* where dump starts on dumpdev */
119 u_int32_t dumpmag;			/* magic number in dump */
120 int	dumpsize;			/* amount of memory dumped */
121 off_t dumpbytes;			/* in bytes */
122 
123 const char	*kernel;		/* name of used kernel */
124 char	*dirname;			/* directory to save dumps in */
125 char	*ddname;			/* name of dump device */
126 dev_t	dumpdev;			/* dump device */
127 int	dumpfd;				/* read/write descriptor on block dev */
128 kvm_t	*kd_dump;			/* kvm descriptor on block dev	*/
129 time_t	now;				/* current date */
130 char	panic_mesg[1024];
131 long	panicstr;
132 char	vers[1024];
133 char	gzmode[3];
134 
135 static int	clear, compress, force, verbose;	/* flags */
136 
137 void	check_kmem(void);
138 int	check_space(void);
139 void	clear_dump(void);
140 int	Create(char *, int);
141 int	dump_exists(void);
142 char	*find_dev(dev_t, int);
143 int	get_crashtime(void);
144 void	kmem_setup(void);
145 void	Lseek(int, off_t, int);
146 int	main(int, char *[]);
147 int	Open(const char *, int rw);
148 char	*rawname(char *s);
149 void	save_core(void);
150 void	usage(void);
151 void	Write(int, void *, int);
152 
153 int
154 main(int argc, char *argv[])
155 {
156 	int ch, level, testonly;
157 	char *ep;
158 
159 	dirname = NULL;
160 	kernel = NULL;
161 	level = 1;		/* default to fastest gzip compression */
162 	testonly = 0;
163 	gzmode[0] = 'w';
164 
165 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
166 
167 	while ((ch = getopt(argc, argv, "cdfnN:vzZ:")) != -1)
168 		switch(ch) {
169 		case 'c':
170 			clear = 1;
171 			break;
172 		case 'd':		/* Not documented. */
173 		case 'v':
174 			verbose = 1;
175 			break;
176 		case 'f':
177 			force = 1;
178 			break;
179 		case 'n':
180 			testonly = 1;
181 			break;
182 		case 'N':
183 			kernel = optarg;
184 			break;
185 		case 'z':
186 			compress = 1;
187 			break;
188 		case 'Z':
189 			level = (int)strtol(optarg, &ep, 10);
190 			if (level < 0 || level > 9) {
191 				(void)syslog(LOG_ERR, "invalid compression %s",
192 				    optarg);
193 				usage();
194 			}
195 			break;
196 		case '?':
197 		default:
198 			usage();
199 		}
200 	argc -= optind;
201 	argv += optind;
202 
203 	if (argc != ((clear || testonly) ? 0 : 1))
204 		usage();
205 
206 	gzmode[1] = level + '0';
207 	if (!clear)
208 		dirname = argv[0];
209 
210 	if (kernel == NULL) {
211 		kernel = getbootfile();
212 	}
213 
214 	(void)time(&now);
215 	kmem_setup();
216 
217 	if (clear && !testonly) {
218 		clear_dump();
219 		exit(0);
220 	}
221 
222 	if (!dump_exists() && !force)
223 		exit(1);
224 
225 	if (testonly)
226 		/* If -n was passed and there was a dump, exit at level 0 */
227 		exit(0);
228 
229 	check_kmem();
230 
231 	if (panicstr)
232 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
233 	else
234 		syslog(LOG_ALERT, "reboot");
235 
236 	if ((!get_crashtime() || !check_space()) && !force)
237 		exit(1);
238 
239 	save_core();
240 
241 	clear_dump();
242 	exit(0);
243 }
244 
245 void
246 kmem_setup(void)
247 {
248 	kvm_t *kd_kern;
249 	char errbuf[_POSIX2_LINE_MAX];
250 	int i, hdrsz;
251 
252 	/*
253 	 * Some names we need for the currently running system, others for
254 	 * the system that was running when the dump was made.  The values
255 	 * obtained from the current system are used to look for things in
256 	 * /dev/kmem that cannot be found in the kernel namelist, but are
257 	 * presumed to be the same (since the disk partitions are probably
258 	 * the same!)
259 	 */
260 	kd_kern = kvm_openfiles(kernel, NULL, NULL, O_RDONLY, errbuf);
261 	if (kd_kern == NULL) {
262 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
263 		exit(1);
264 	}
265 	if (kvm_nlist(kd_kern, current_nl) == -1)
266 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
267 		    kvm_geterr(kd_kern));
268 
269 	for (i = 0; cursyms[i] != -1; i++)
270 		if (current_nl[cursyms[i]].n_value == 0 &&
271 			cursyms[i] != X_TIME_SECOND &&
272 		        cursyms[i] != X_TIME) {
273 			syslog(LOG_ERR, "%s: %s not in namelist",
274 			    kernel, current_nl[cursyms[i]].n_name);
275 			exit(1);
276 		}
277 
278 	if (KREAD(kd_kern, current_nl[X_DUMPDEV].n_value, &dumpdev) != 0) {
279 		if (verbose)
280 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
281 		exit(1);
282 	}
283 	if (dumpdev == NODEV) {
284 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
285 		exit(1);
286 	}
287 	{
288 	    long l_dumplo;
289 
290 	    if (KREAD(kd_kern, current_nl[X_DUMPLO].n_value, &l_dumplo) != 0) {
291 		    if (verbose)
292 			syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
293 		    exit(1);
294 	    }
295 	    if (l_dumplo == -1) {
296 		syslog(LOG_WARNING, "no core dump (invalid dumplo)");
297 		exit(1);
298 	    }
299 	    dumplo = DEV_BSIZE * (off_t) l_dumplo;
300 	}
301 
302 	if (verbose)
303 		(void)printf("dumplo = %lld (%ld * %ld)\n",
304 		    (long long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
305 	if (KREAD(kd_kern, current_nl[X_DUMPMAG].n_value, &dumpmag) != 0) {
306 		if (verbose)
307 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
308 		exit(1);
309 	}
310 
311 	(void)kvm_read(kd_kern, current_nl[X_VERSION].n_value, vers,
312 	    sizeof(vers));
313 	vers[sizeof(vers) - 1] = '\0';
314 
315 	ddname = find_dev(dumpdev, S_IFBLK);
316 	dumpfd = Open(ddname, O_RDWR);
317 
318 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
319 	if (kd_dump == NULL) {
320 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
321 		exit(1);
322 	}
323 
324 	if (kvm_nlist(kd_dump, dump_nl) == -1)
325 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
326 		    kvm_geterr(kd_dump));
327 
328 	for (i = 0; dumpsyms[i] != -1; i++)
329 		if (dump_nl[dumpsyms[i]].n_value == 0 &&
330 			dumpsyms[i] != X_TIME_SECOND &&
331 			dumpsyms[i] != X_TIME) {
332 			syslog(LOG_ERR, "%s: %s not in namelist",
333 			    kernel, dump_nl[dumpsyms[i]].n_name);
334 			exit(1);
335 		}
336 	hdrsz = kvm_dump_mkheader(kd_dump, dumplo);
337 
338 	/*
339 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
340 	 * checks, ergo no dump is present...
341 	 */
342 	if (hdrsz == 0) {
343 		syslog(LOG_WARNING, "no core dump");
344 		exit(1);
345 	}
346 	if (hdrsz == -1) {
347 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
348 		    kvm_geterr(kd_dump));
349 		exit(1);
350 	}
351 	dumplo += hdrsz;
352 	kvm_close(kd_kern);
353 }
354 
355 void
356 check_kmem(void)
357 {
358 	char *cp, *bufdata;
359 	struct kern_msgbuf msgbuf, *bufp;
360 	long panicloc, panicstart, panicend;
361 	char core_vers[1024];
362 
363 	(void)kvm_read(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
364 	    sizeof(core_vers));
365 	core_vers[sizeof(core_vers) - 1] = '\0';
366 
367 	if (strcmp(vers, core_vers) != 0)
368 		syslog(LOG_WARNING,
369 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
370 		    kernel, vers, core_vers);
371 
372 	panicstart = panicend = 0;
373 	if (KREAD(kd_dump, dump_nl[X_PANICSTART].n_value, &panicstart) != 0) {
374 		if (verbose)
375 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
376 		goto nomsguf;
377 	}
378 	if (KREAD(kd_dump, dump_nl[X_PANICEND].n_value, &panicend) != 0) {
379 		if (verbose)
380 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
381 		goto nomsguf;
382 	}
383 	if (panicstart != 0 && panicend != 0) {
384 		if (KREAD(kd_dump, dump_nl[X_MSGBUF].n_value, &bufp)) {
385 			if (verbose)
386 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
387 			goto nomsguf;
388 		}
389 		if (kvm_read(kd_dump, (long)bufp, &msgbuf,
390 		    offsetof(struct kern_msgbuf, msg_bufc)) !=
391 		    offsetof(struct kern_msgbuf, msg_bufc)) {
392 			if (verbose)
393 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
394 			goto nomsguf;
395 		}
396 		if (msgbuf.msg_magic != MSG_MAGIC) {
397 			if (verbose)
398 				syslog(LOG_WARNING, "msgbuf magic incorrect");
399 			goto nomsguf;
400 		}
401 		bufdata = malloc(msgbuf.msg_bufs);
402 		if (bufdata == NULL) {
403 			if (verbose)
404 				syslog(LOG_WARNING, "couldn't allocate space for msgbuf data");
405 			goto nomsguf;
406 		}
407 		if (kvm_read(kd_dump, (long)&bufp->msg_bufc, bufdata,
408 		    msgbuf.msg_bufs) != msgbuf.msg_bufs) {
409 			if (verbose)
410 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
411 			free(bufdata);
412 			goto nomsguf;
413 		}
414 		cp = panic_mesg;
415 		while (panicstart != panicend && cp < &panic_mesg[sizeof(panic_mesg)-1]) {
416 			*cp++ = bufdata[panicstart];
417 			panicstart++;
418 			if (panicstart >= msgbuf.msg_bufs)
419 				panicstart = 0;
420 		}
421 		/* Don't end in a new-line */
422 		cp = &panic_mesg[strlen(panic_mesg)] - 1;
423 		if (*cp == '\n')
424 			*cp = '\0';
425 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
426 		free(bufdata);
427 
428 		panicstr = 1;	/* anything not zero */
429 		return;
430 	}
431 nomsguf:
432 	if (KREAD(kd_dump, dump_nl[X_PANICSTR].n_value, &panicstr) != 0) {
433 		if (verbose)
434 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
435 		return;
436 	}
437 	if (panicstr) {
438 		cp = panic_mesg;
439 		panicloc = panicstr;
440 		do {
441 			if (KREAD(kd_dump, panicloc, cp) != 0) {
442 				if (verbose)
443 				    syslog(LOG_WARNING, "kvm_read: %s",
444 					kvm_geterr(kd_dump));
445 				break;
446 			}
447 			panicloc++;
448 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
449 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
450 	}
451 }
452 
453 int
454 dump_exists(void)
455 {
456 	u_int32_t newdumpmag;
457 
458 	if (KREAD(kd_dump, dump_nl[X_DUMPMAG].n_value, &newdumpmag) != 0) {
459 		if (verbose)
460 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
461 		return (0);
462 	}
463 
464 	/* Read the dump size. */
465 	if (KREAD(kd_dump, dump_nl[X_DUMPSIZE].n_value, &dumpsize) != 0) {
466 		if (verbose)
467 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
468 		return (0);
469 	}
470 	dumpbytes = (off_t)dumpsize * getpagesize();
471 
472 	/*
473 	 * Return zero if core dump doesn't seem to be there, and note
474 	 * it for syslog.  This check and return happens after the dump size
475 	 * is read, so dumpsize is whether or not the core is valid (for -f).
476 	 */
477 	if (newdumpmag != dumpmag) {
478 		if (verbose)
479 			syslog(LOG_WARNING,
480 			    "magic number mismatch (0x%x != 0x%x)",
481 			    newdumpmag, dumpmag);
482 		syslog(LOG_WARNING, "no core dump");
483 		return (0);
484 	}
485 	return (1);
486 }
487 
488 void
489 clear_dump(void)
490 {
491 	if (kvm_dump_inval(kd_dump) == -1)
492 		syslog(LOG_ERR, "%s: kvm_clear_dump: %s", ddname,
493 		    kvm_geterr(kd_dump));
494 
495 }
496 
497 char buf[1024 * 1024];
498 
499 void
500 save_core(void)
501 {
502 	FILE *fp;
503 	int bounds, ifd, nr, nw, ofd;
504 	char *rawp, path[MAXPATHLEN];
505 
506 	ofd = -1;
507 	/*
508 	 * Get the current number and update the bounds file.  Do the update
509 	 * now, because may fail later and don't want to overwrite anything.
510 	 */
511 	umask(066);
512 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
513 	if ((fp = fopen(path, "r")) == NULL)
514 		goto err1;
515 	if (fgets(buf, sizeof(buf), fp) == NULL) {
516 		if (ferror(fp))
517 err1:			syslog(LOG_WARNING, "%s: %m", path);
518 		bounds = 0;
519 	} else
520 		bounds = atoi(buf);
521 	if (fp != NULL)
522 		(void)fclose(fp);
523 	if ((fp = fopen(path, "w")) == NULL)
524 		syslog(LOG_ERR, "%s: %m", path);
525 	else {
526 		(void)fprintf(fp, "%d\n", bounds + 1);
527 		(void)fclose(fp);
528 	}
529 
530 	/* Create the core file. */
531 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
532 	    dirname, bounds, compress ? ".gz" : "");
533 	if (compress) {
534 		if ((fp = zopen(path, gzmode)) == NULL) {
535 			syslog(LOG_ERR, "%s: %m", path);
536 			exit(1);
537 		}
538 	} else {
539 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
540 		fp  = fdopen(ofd, "w");
541 		if (fp == NULL) {
542 			syslog(LOG_ERR, "%s: fdopen: %m", path);
543 			exit(1);
544 		}
545 	}
546 
547 	/* Open the raw device. */
548 	rawp = rawname(ddname);
549 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
550 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
551 		ifd = dumpfd;
552 	}
553 
554 	/* Seek to the start of the core. */
555 	Lseek(ifd, dumplo, SEEK_SET);
556 
557 	if (kvm_dump_wrtheader(kd_dump, fp, (int32_t)dumpbytes) == -1) {
558 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
559 		    kvm_geterr(kd_dump));
560 		exit(1);
561 	}
562 
563 	/* Copy the core file. */
564 	syslog(LOG_NOTICE, "writing %score to %s",
565 	    compress ? "compressed " : "", path);
566 	for (; dumpbytes > (off_t)0; dumpbytes -= (off_t)nr) {
567 		char nbuf[7];
568 		humanize_number(nbuf, 7, dumpbytes, "", HN_AUTOSCALE, 0);
569 		(void)printf("%7s\r", nbuf);
570 		(void)fflush(stdout);
571 		nr = read(ifd, buf, MIN(dumpbytes, sizeof(buf)));
572 		if (nr <= 0) {
573 			if (nr == 0)
574 				syslog(LOG_WARNING,
575 				    "WARNING: EOF on dump device");
576 			else
577 				syslog(LOG_ERR, "%s: %m", rawp);
578 			goto err2;
579 		}
580 		nw = fwrite(buf, 1, nr, fp);
581 		if (nw != nr) {
582 			syslog(LOG_ERR, "%s: %s",
583 			    path, strerror(nw == 0 ? EIO : errno));
584 err2:			syslog(LOG_WARNING,
585 			    "WARNING: core may be incomplete");
586 			(void)printf("\n");
587 			exit(1);
588 		}
589 	}
590 	(void)close(ifd);
591 	(void)fclose(fp);
592 
593 	/* Copy the kernel. */
594 	ifd = Open(kernel, O_RDONLY);
595 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
596 	    dirname, bounds, compress ? ".gz" : "");
597 	if (compress) {
598 		if ((fp = zopen(path, gzmode)) == NULL) {
599 			syslog(LOG_ERR, "%s: %m", path);
600 			exit(1);
601 		}
602 	} else
603 		ofd = Create(path, S_IRUSR | S_IWUSR);
604 	syslog(LOG_NOTICE, "writing %skernel to %s",
605 	    compress ? "compressed " : "", path);
606 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
607 		if (compress)
608 			nw = fwrite(buf, 1, nr, fp);
609 		else
610 			nw = write(ofd, buf, nr);
611 		if (nw != nr) {
612 			syslog(LOG_ERR, "%s: %s",
613 			    path, strerror(nw == 0 ? EIO : errno));
614 			syslog(LOG_WARNING,
615 			    "WARNING: kernel may be incomplete");
616 			exit(1);
617 		}
618 	}
619 	if (nr < 0) {
620 		syslog(LOG_ERR, "%s: %m", kernel);
621 		syslog(LOG_WARNING, "WARNING: kernel may be incomplete");
622 		exit(1);
623 	}
624 	if (compress)
625 		(void)fclose(fp);
626 	else
627 		(void)close(ofd);
628 }
629 
630 char *
631 find_dev(dev_t dev, int type)
632 {
633 	DIR *dfd;
634 	struct dirent *dir;
635 	struct stat sb;
636 	char *dp, device[MAXPATHLEN + 1], *p;
637 	size_t l;
638 
639 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
640 		syslog(LOG_ERR, "%s: %m", _PATH_DEV);
641 		exit(1);
642 	}
643 	strlcpy(device, _PATH_DEV, sizeof(device));
644 	p = &device[strlen(device)];
645 	l = sizeof(device) - strlen(device);
646 	while ((dir = readdir(dfd))) {
647 		strlcpy(p, dir->d_name, l);
648 		if (lstat(device, &sb)) {
649 			syslog(LOG_ERR, "%s: %m", device);
650 			continue;
651 		}
652 		if ((sb.st_mode & S_IFMT) != type)
653 			continue;
654 		if (dev == sb.st_rdev) {
655 			closedir(dfd);
656 			if ((dp = strdup(device)) == NULL) {
657 				syslog(LOG_ERR, "%m");
658 				exit(1);
659 			}
660 			return (dp);
661 		}
662 	}
663 	closedir(dfd);
664 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
665 	exit(1);
666 }
667 
668 char *
669 rawname(char *s)
670 {
671 	char *sl;
672 	char name[MAXPATHLEN];
673 
674 	if ((sl = strrchr(s, '/')) == NULL || sl[1] == '0') {
675 		syslog(LOG_ERR,
676 		    "can't make raw dump device name from %s", s);
677 		return (s);
678 	}
679 	(void)snprintf(name, sizeof(name), "%.*s/r%s", (int)(sl - s), s,
680 	    sl + 1);
681 	if ((sl = strdup(name)) == NULL) {
682 		syslog(LOG_ERR, "%m");
683 		exit(1);
684 	}
685 	return (sl);
686 }
687 
688 int
689 get_crashtime(void)
690 {
691 	time_t dumptime;			/* Time the dump was taken. */
692 	struct timeval dtime;
693 
694 	if (KREAD(kd_dump, dump_nl[X_TIME_SECOND].n_value, &dumptime) != 0) {
695 		if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &dtime) != 0) {
696 			if (verbose)
697 				syslog(LOG_WARNING, "kvm_read: %s (and _time_second is not defined also)", kvm_geterr(kd_dump));
698 			return (0);
699 		}
700 		dumptime = dtime.tv_sec;
701 	}
702 	if (dumptime == 0) {
703 		if (verbose)
704 			syslog(LOG_ERR, "dump time is zero");
705 		return (0);
706 	}
707 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
708 #define	LEEWAY	(60 * SECSPERDAY)
709 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
710 		(void)printf("dump time is unreasonable\n");
711 		return (0);
712 	}
713 	return (1);
714 }
715 
716 int
717 check_space(void)
718 {
719 	FILE *fp;
720 	off_t minfree, spacefree, kernelsize, needed;
721 	struct stat st;
722 	struct statvfs fsbuf;
723 	char mbuf[100], path[MAXPATHLEN];
724 
725 	if (stat(kernel, &st) < 0) {
726 		syslog(LOG_ERR, "%s: %m", kernel);
727 		exit(1);
728 	}
729 	kernelsize = st.st_blocks * S_BLKSIZE;
730 	if (statvfs(dirname, &fsbuf) < 0) {
731 		syslog(LOG_ERR, "%s: %m", dirname);
732 		exit(1);
733 	}
734 	spacefree = fsbuf.f_bavail;
735 	spacefree *= fsbuf.f_frsize;
736 	spacefree /= 1024;
737 
738 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
739 	if ((fp = fopen(path, "r")) == NULL)
740 		minfree = 0;
741 	else {
742 		if (fgets(mbuf, sizeof(mbuf), fp) == NULL)
743 			minfree = 0;
744 		else
745 			minfree = atoi(mbuf);
746 		(void)fclose(fp);
747 	}
748 
749 	needed = (dumpbytes + kernelsize) / 1024;
750  	if (minfree > 0 && spacefree - needed < minfree) {
751 		syslog(LOG_WARNING,
752 		    "no dump, not enough free space in %s", dirname);
753 		return (0);
754 	}
755 	if (spacefree - needed < minfree)
756 		syslog(LOG_WARNING,
757 		    "dump performed, but free space threshold crossed");
758 	return (1);
759 }
760 
761 int
762 Open(const char *name, int rw)
763 {
764 	int fd;
765 
766 	if ((fd = open(name, rw, 0)) < 0) {
767 		syslog(LOG_ERR, "%s: %m", name);
768 		exit(1);
769 	}
770 	return (fd);
771 }
772 
773 void
774 Lseek(int fd, off_t off, int flag)
775 {
776 	off_t ret;
777 
778 	ret = lseek(fd, off, flag);
779 	if (ret == -1) {
780 		syslog(LOG_ERR, "lseek: %m");
781 		exit(1);
782 	}
783 }
784 
785 int
786 Create(char *file, int mode)
787 {
788 	int fd;
789 
790 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
791 	if (fd < 0) {
792 		syslog(LOG_ERR, "%s: %m", file);
793 		exit(1);
794 	}
795 	return (fd);
796 }
797 
798 void
799 Write(int fd, void *bp, int size)
800 {
801 	int n;
802 
803 	if ((n = write(fd, bp, size)) < size) {
804 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
805 		exit(1);
806 	}
807 }
808 
809 void
810 usage(void)
811 {
812 	(void)syslog(LOG_ERR,
813 	    "usage: savecore [-cfnvz] [-N system] [-Z level] directory");
814 	exit(1);
815 }
816