xref: /netbsd/sbin/savecore/savecore.c (revision c4a72b64)
1 /*	$NetBSD: savecore.c,v 1.59 2002/12/06 02:20:00 thorpej 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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #ifndef lint
38 __COPYRIGHT("@(#) Copyright (c) 1986, 1992, 1993\n\
39 	The Regents of the University of California.  All rights reserved.\n");
40 #endif /* not lint */
41 
42 #ifndef lint
43 #if 0
44 static char sccsid[] = "@(#)savecore.c	8.5 (Berkeley) 4/28/95";
45 #else
46 __RCSID("$NetBSD: savecore.c,v 1.59 2002/12/06 02:20:00 thorpej Exp $");
47 #endif
48 #endif /* not lint */
49 
50 #include <sys/param.h>
51 #include <sys/mount.h>
52 #include <sys/msgbuf.h>
53 #include <sys/syslog.h>
54 #include <sys/time.h>
55 
56 #include <dirent.h>
57 #include <errno.h>
58 #include <fcntl.h>
59 #include <nlist.h>
60 #include <paths.h>
61 #include <stddef.h>
62 #include <stdio.h>
63 #include <stdlib.h>
64 #include <string.h>
65 #include <time.h>
66 #include <tzfile.h>
67 #include <unistd.h>
68 #include <util.h>
69 #include <limits.h>
70 #include <kvm.h>
71 
72 extern FILE *zopen(const char *fname, const char *mode);
73 
74 #define	KREAD(kd, addr, p)\
75 	(kvm_read(kd, addr, (char *)(p), sizeof(*(p))) != sizeof(*(p)))
76 
77 struct nlist current_nl[] = {	/* Namelist for currently running system. */
78 #define	X_DUMPDEV	0
79 	{ "_dumpdev" },
80 #define	X_DUMPLO	1
81 	{ "_dumplo" },
82 #define	X_TIME		2
83 	{ "_time" },
84 #define	X_DUMPSIZE	3
85 	{ "_dumpsize" },
86 #define	X_VERSION	4
87 	{ "_version" },
88 #define	X_DUMPMAG	5
89 	{ "_dumpmag" },
90 #define	X_PANICSTR	6
91 	{ "_panicstr" },
92 #define	X_PANICSTART	7
93 	{ "_panicstart" },
94 #define	X_PANICEND	8
95 	{ "_panicend" },
96 #define	X_MSGBUF	9
97 	{ "_msgbufp" },
98 	{ NULL },
99 };
100 int cursyms[] = { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
101 int dumpsyms[] = { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
102 
103 struct nlist dump_nl[] = {	/* Name list for dumped system. */
104 	{ "_dumpdev" },		/* Entries MUST be the same as */
105 	{ "_dumplo" },		/*	those in current_nl[].  */
106 	{ "_time" },
107 	{ "_dumpsize" },
108 	{ "_version" },
109 	{ "_dumpmag" },
110 	{ "_panicstr" },
111 	{ "_panicstart" },
112 	{ "_panicend" },
113 	{ "_msgbufp" },
114 	{ 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 
122 const char	*kernel;		/* name of used kernel */
123 char	*dirname;			/* directory to save dumps in */
124 char	*ddname;			/* name of dump device */
125 dev_t	dumpdev;			/* dump device */
126 int	dumpfd;				/* read/write descriptor on block dev */
127 kvm_t	*kd_dump;			/* kvm descriptor on block dev	*/
128 time_t	now;				/* current date */
129 char	panic_mesg[1024];
130 long	panicstr;
131 char	vers[1024];
132 char	gzmode[3];
133 
134 static int	clear, compress, force, verbose;	/* flags */
135 
136 void	check_kmem(void);
137 int	check_space(void);
138 void	clear_dump(void);
139 int	Create(char *, int);
140 int	dump_exists(void);
141 char	*find_dev(dev_t, int);
142 int	get_crashtime(void);
143 void	kmem_setup(void);
144 void	Lseek(int, off_t, int);
145 int	main(int, char *[]);
146 int	Open(const char *, int rw);
147 char	*rawname(char *s);
148 void	save_core(void);
149 void	usage(void);
150 void	Write(int, void *, int);
151 
152 int
153 main(int argc, char *argv[])
154 {
155 	int ch, level;
156 	char *ep;
157 
158 	dirname = NULL;
159 	kernel = NULL;
160 	level = 1;		/* default to fastest gzip compression */
161 	gzmode[0] = 'w';
162 
163 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
164 
165 	while ((ch = getopt(argc, argv, "cdfN:vzZ:")) != -1)
166 		switch(ch) {
167 		case 'c':
168 			clear = 1;
169 			break;
170 		case 'd':		/* Not documented. */
171 		case 'v':
172 			verbose = 1;
173 			break;
174 		case 'f':
175 			force = 1;
176 			break;
177 		case 'N':
178 			kernel = optarg;
179 			break;
180 		case 'z':
181 			compress = 1;
182 			break;
183 		case 'Z':
184 			level = (int)strtol(optarg, &ep, 10);
185 			if (level < 0 || level > 9) {
186 				(void)syslog(LOG_ERR, "invalid compression %s",
187 				    optarg);
188 				usage();
189 			}
190 			break;
191 		case '?':
192 		default:
193 			usage();
194 		}
195 	argc -= optind;
196 	argv += optind;
197 
198 	if (argc != (clear ? 0 : 1))
199 		usage();
200 
201 	gzmode[1] = level + '0';
202 	if (!clear)
203 		dirname = argv[0];
204 
205 	if (kernel == NULL) {
206 		kernel = getbootfile();
207 	}
208 
209 	(void)time(&now);
210 	kmem_setup();
211 
212 	if (clear) {
213 		clear_dump();
214 		exit(0);
215 	}
216 
217 	if (!dump_exists() && !force)
218 		exit(1);
219 
220 	check_kmem();
221 
222 	if (panicstr)
223 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
224 	else
225 		syslog(LOG_ALERT, "reboot");
226 
227 	if ((!get_crashtime() || !check_space()) && !force)
228 		exit(1);
229 
230 	save_core();
231 
232 	clear_dump();
233 	exit(0);
234 }
235 
236 void
237 kmem_setup(void)
238 {
239 	kvm_t *kd_kern;
240 	char errbuf[_POSIX2_LINE_MAX];
241 	int i, hdrsz;
242 
243 	/*
244 	 * Some names we need for the currently running system, others for
245 	 * the system that was running when the dump was made.  The values
246 	 * obtained from the current system are used to look for things in
247 	 * /dev/kmem that cannot be found in the kernel namelist, but are
248 	 * presumed to be the same (since the disk partitions are probably
249 	 * the same!)
250 	 */
251 	kd_kern = kvm_openfiles(kernel, NULL, NULL, O_RDONLY, errbuf);
252 	if (kd_kern == NULL) {
253 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
254 		exit(1);
255 	}
256 	if (kvm_nlist(kd_kern, current_nl) == -1)
257 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
258 		    kvm_geterr(kd_kern));
259 
260 	for (i = 0; cursyms[i] != -1; i++)
261 		if (current_nl[cursyms[i]].n_value == 0) {
262 			syslog(LOG_ERR, "%s: %s not in namelist",
263 			    kernel, current_nl[cursyms[i]].n_name);
264 			exit(1);
265 		}
266 
267 	if (KREAD(kd_kern, current_nl[X_DUMPDEV].n_value, &dumpdev) != 0) {
268 		if (verbose)
269 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
270 		exit(1);
271 	}
272 	if (dumpdev == NODEV) {
273 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
274 		exit(1);
275 	}
276 	{
277 	    long l_dumplo;
278 
279 	    if (KREAD(kd_kern, current_nl[X_DUMPLO].n_value, &l_dumplo) != 0) {
280 		    if (verbose)
281 			syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
282 		    exit(1);
283 	    }
284 	    if (l_dumplo == -1) {
285 		syslog(LOG_WARNING, "no core dump (invalid dumplo)");
286 		exit(1);
287 	    }
288 	    dumplo = DEV_BSIZE * (off_t) l_dumplo;
289 	}
290 
291 	if (verbose)
292 		(void)printf("dumplo = %lld (%ld * %ld)\n",
293 		    (long long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
294 	if (KREAD(kd_kern, current_nl[X_DUMPMAG].n_value, &dumpmag) != 0) {
295 		if (verbose)
296 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
297 		exit(1);
298 	}
299 
300 	(void)kvm_read(kd_kern, current_nl[X_VERSION].n_value, vers,
301 	    sizeof(vers));
302 	vers[sizeof(vers) - 1] = '\0';
303 
304 	ddname = find_dev(dumpdev, S_IFBLK);
305 	dumpfd = Open(ddname, O_RDWR);
306 
307 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
308 	if (kd_dump == NULL) {
309 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
310 		exit(1);
311 	}
312 
313 	if (kvm_nlist(kd_dump, dump_nl) == -1)
314 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
315 		    kvm_geterr(kd_dump));
316 
317 	for (i = 0; dumpsyms[i] != -1; i++)
318 		if (dump_nl[dumpsyms[i]].n_value == 0) {
319 			syslog(LOG_ERR, "%s: %s not in namelist",
320 			    kernel, dump_nl[dumpsyms[i]].n_name);
321 			exit(1);
322 		}
323 	hdrsz = kvm_dump_mkheader(kd_dump, dumplo);
324 
325 	/*
326 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
327 	 * checks, ergo no dump is present...
328 	 */
329 	if (hdrsz == 0) {
330 		syslog(LOG_WARNING, "no core dump");
331 		exit(1);
332 	}
333 	if (hdrsz == -1) {
334 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
335 		    kvm_geterr(kd_dump));
336 		exit(1);
337 	}
338 	dumplo += hdrsz;
339 	kvm_close(kd_kern);
340 }
341 
342 void
343 check_kmem(void)
344 {
345 	char *cp, *bufdata;
346 	struct kern_msgbuf msgbuf, *bufp;
347 	long panicloc, panicstart, panicend;
348 	char core_vers[1024];
349 
350 	(void)kvm_read(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
351 	    sizeof(core_vers));
352 	core_vers[sizeof(core_vers) - 1] = '\0';
353 
354 	if (strcmp(vers, core_vers) != 0)
355 		syslog(LOG_WARNING,
356 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
357 		    kernel, vers, core_vers);
358 
359 	panicstart = panicend = 0;
360 	if (KREAD(kd_dump, dump_nl[X_PANICSTART].n_value, &panicstart) != 0) {
361 		if (verbose)
362 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
363 		goto nomsguf;
364 	}
365 	if (KREAD(kd_dump, dump_nl[X_PANICEND].n_value, &panicend) != 0) {
366 		if (verbose)
367 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
368 		goto nomsguf;
369 	}
370 	if (panicstart != 0 && panicend != 0) {
371 		if (KREAD(kd_dump, dump_nl[X_MSGBUF].n_value, &bufp)) {
372 			if (verbose)
373 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
374 			goto nomsguf;
375 		}
376 		if (kvm_read(kd_dump, (long)bufp, &msgbuf,
377 		    offsetof(struct kern_msgbuf, msg_bufc)) !=
378 		    offsetof(struct kern_msgbuf, msg_bufc)) {
379 			if (verbose)
380 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
381 			goto nomsguf;
382 		}
383 		if (msgbuf.msg_magic != MSG_MAGIC) {
384 			if (verbose)
385 				syslog(LOG_WARNING, "msgbuf magic incorrect");
386 			goto nomsguf;
387 		}
388 		bufdata = malloc(msgbuf.msg_bufs);
389 		if (bufdata == NULL) {
390 			if (verbose)
391 				syslog(LOG_WARNING, "couldn't allocate space for msgbuf data");
392 			goto nomsguf;
393 		}
394 		if (kvm_read(kd_dump, (long)&bufp->msg_bufc, bufdata,
395 		    msgbuf.msg_bufs) != msgbuf.msg_bufs) {
396 			if (verbose)
397 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
398 			goto nomsguf;
399 		}
400 		cp = panic_mesg;
401 		while (panicstart != panicend && cp < &panic_mesg[sizeof(panic_mesg)-1]) {
402 			*cp++ = bufdata[panicstart];
403 			panicstart++;
404 			if (panicstart >= msgbuf.msg_bufs)
405 				panicstart = 0;
406 		}
407 		/* Don't end in a new-line */
408 		cp = &panic_mesg[strlen(panic_mesg)] - 1;
409 		if (*cp == '\n')
410 			*cp = '\0';
411 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
412 
413 		panicstr = 1;	/* anything not zero */
414 		return;
415 	}
416 nomsguf:
417 	if (KREAD(kd_dump, dump_nl[X_PANICSTR].n_value, &panicstr) != 0) {
418 		if (verbose)
419 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
420 		return;
421 	}
422 	if (panicstr) {
423 		cp = panic_mesg;
424 		panicloc = panicstr;
425 		do {
426 			if (KREAD(kd_dump, panicloc, cp) != 0) {
427 				if (verbose)
428 				    syslog(LOG_WARNING, "kvm_read: %s",
429 					kvm_geterr(kd_dump));
430 				break;
431 			}
432 			panicloc++;
433 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
434 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
435 	}
436 }
437 
438 int
439 dump_exists(void)
440 {
441 	u_int32_t newdumpmag;
442 
443 	if (KREAD(kd_dump, dump_nl[X_DUMPMAG].n_value, &newdumpmag) != 0) {
444 		if (verbose)
445 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
446 		return (0);
447 	}
448 
449 	/* Read the dump size. */
450 	if (KREAD(kd_dump, dump_nl[X_DUMPSIZE].n_value, &dumpsize) != 0) {
451 		if (verbose)
452 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
453 		return (0);
454 	}
455 	dumpsize *= getpagesize();
456 
457 	/*
458 	 * Return zero if core dump doesn't seem to be there, and note
459 	 * it for syslog.  This check and return happens after the dump size
460 	 * is read, so dumpsize is whether or not the core is valid (for -f).
461 	 */
462 	if (newdumpmag != dumpmag) {
463 		if (verbose)
464 			syslog(LOG_WARNING,
465 			    "magic number mismatch (0x%x != 0x%x)",
466 			    newdumpmag, dumpmag);
467 		syslog(LOG_WARNING, "no core dump");
468 		return (0);
469 	}
470 	return (1);
471 }
472 
473 void
474 clear_dump(void)
475 {
476 	if (kvm_dump_inval(kd_dump) == -1)
477 		syslog(LOG_ERR, "%s: kvm_clear_dump: %s", ddname,
478 		    kvm_geterr(kd_dump));
479 
480 }
481 
482 char buf[1024 * 1024];
483 
484 void
485 save_core(void)
486 {
487 	FILE *fp;
488 	int bounds, ifd, nr, nw, ofd;
489 	char *rawp, path[MAXPATHLEN];
490 
491 	ofd = -1;
492 	/*
493 	 * Get the current number and update the bounds file.  Do the update
494 	 * now, because may fail later and don't want to overwrite anything.
495 	 */
496 	umask(066);
497 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
498 	if ((fp = fopen(path, "r")) == NULL)
499 		goto err1;
500 	if (fgets(buf, sizeof(buf), fp) == NULL) {
501 		if (ferror(fp))
502 err1:			syslog(LOG_WARNING, "%s: %m", path);
503 		bounds = 0;
504 	} else
505 		bounds = atoi(buf);
506 	if (fp != NULL)
507 		(void)fclose(fp);
508 	if ((fp = fopen(path, "w")) == NULL)
509 		syslog(LOG_ERR, "%s: %m", path);
510 	else {
511 		(void)fprintf(fp, "%d\n", bounds + 1);
512 		(void)fclose(fp);
513 	}
514 
515 	/* Create the core file. */
516 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
517 	    dirname, bounds, compress ? ".gz" : "");
518 	if (compress) {
519 		if ((fp = zopen(path, gzmode)) == NULL) {
520 			syslog(LOG_ERR, "%s: %m", path);
521 			exit(1);
522 		}
523 	} else {
524 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
525 		fp  = fdopen(ofd, "w");
526 		if (fp == NULL) {
527 			syslog(LOG_ERR, "%s: fdopen: %m", path);
528 			exit(1);
529 		}
530 	}
531 
532 	/* Open the raw device. */
533 	rawp = rawname(ddname);
534 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
535 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
536 		ifd = dumpfd;
537 	}
538 
539 	/* Seek to the start of the core. */
540 	Lseek(ifd, dumplo, SEEK_SET);
541 
542 	if (kvm_dump_wrtheader(kd_dump, fp, dumpsize) == -1) {
543 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
544 		    kvm_geterr(kd_dump));
545 		exit(1);
546 	}
547 
548 	/* Copy the core file. */
549 	syslog(LOG_NOTICE, "writing %score to %s",
550 	    compress ? "compressed " : "", path);
551 	for (; dumpsize > 0; dumpsize -= nr) {
552 		char nbuf[7];
553 		humanize_number(nbuf, 7, dumpsize, "", HN_AUTOSCALE, 0);
554 		(void)printf("%7s\r", nbuf);
555 		(void)fflush(stdout);
556 		nr = read(ifd, buf, MIN(dumpsize, sizeof(buf)));
557 		if (nr <= 0) {
558 			if (nr == 0)
559 				syslog(LOG_WARNING,
560 				    "WARNING: EOF on dump device");
561 			else
562 				syslog(LOG_ERR, "%s: %m", rawp);
563 			goto err2;
564 		}
565 		nw = fwrite(buf, 1, nr, fp);
566 		if (nw != nr) {
567 			syslog(LOG_ERR, "%s: %s",
568 			    path, strerror(nw == 0 ? EIO : errno));
569 err2:			syslog(LOG_WARNING,
570 			    "WARNING: core may be incomplete");
571 			(void)printf("\n");
572 			exit(1);
573 		}
574 	}
575 	(void)close(ifd);
576 	(void)fclose(fp);
577 
578 	/* Copy the kernel. */
579 	ifd = Open(kernel, O_RDONLY);
580 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
581 	    dirname, bounds, compress ? ".gz" : "");
582 	if (compress) {
583 		if ((fp = zopen(path, gzmode)) == NULL) {
584 			syslog(LOG_ERR, "%s: %m", path);
585 			exit(1);
586 		}
587 	} else
588 		ofd = Create(path, S_IRUSR | S_IWUSR);
589 	syslog(LOG_NOTICE, "writing %skernel to %s",
590 	    compress ? "compressed " : "", path);
591 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
592 		if (compress)
593 			nw = fwrite(buf, 1, nr, fp);
594 		else
595 			nw = write(ofd, buf, nr);
596 		if (nw != nr) {
597 			syslog(LOG_ERR, "%s: %s",
598 			    path, strerror(nw == 0 ? EIO : errno));
599 			syslog(LOG_WARNING,
600 			    "WARNING: kernel may be incomplete");
601 			exit(1);
602 		}
603 	}
604 	if (nr < 0) {
605 		syslog(LOG_ERR, "%s: %m", kernel);
606 		syslog(LOG_WARNING, "WARNING: kernel may be incomplete");
607 		exit(1);
608 	}
609 	if (compress)
610 		(void)fclose(fp);
611 	else
612 		(void)close(ofd);
613 }
614 
615 char *
616 find_dev(dev_t dev, int type)
617 {
618 	DIR *dfd;
619 	struct dirent *dir;
620 	struct stat sb;
621 	char *dp, device[MAXPATHLEN + 1];
622 
623 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
624 		syslog(LOG_ERR, "%s: %m", _PATH_DEV);
625 		exit(1);
626 	}
627 	(void)strcpy(device, _PATH_DEV);
628 	while ((dir = readdir(dfd))) {
629 		(void)strcpy(device + sizeof(_PATH_DEV) - 1, dir->d_name);
630 		if (lstat(device, &sb)) {
631 			syslog(LOG_ERR, "%s: %m", device);
632 			continue;
633 		}
634 		if ((sb.st_mode & S_IFMT) != type)
635 			continue;
636 		if (dev == sb.st_rdev) {
637 			closedir(dfd);
638 			if ((dp = strdup(device)) == NULL) {
639 				syslog(LOG_ERR, "%m");
640 				exit(1);
641 			}
642 			return (dp);
643 		}
644 	}
645 	closedir(dfd);
646 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
647 	exit(1);
648 }
649 
650 char *
651 rawname(char *s)
652 {
653 	char *sl;
654 	char name[MAXPATHLEN];
655 
656 	if ((sl = strrchr(s, '/')) == NULL || sl[1] == '0') {
657 		syslog(LOG_ERR,
658 		    "can't make raw dump device name from %s", s);
659 		return (s);
660 	}
661 	(void)snprintf(name, sizeof(name), "%.*s/r%s", (int)(sl - s), s,
662 	    sl + 1);
663 	if ((sl = strdup(name)) == NULL) {
664 		syslog(LOG_ERR, "%m");
665 		exit(1);
666 	}
667 	return (sl);
668 }
669 
670 int
671 get_crashtime(void)
672 {
673 	struct timeval dtime;
674 	time_t dumptime;			/* Time the dump was taken. */
675 
676 	if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &dtime) != 0) {
677 		if (verbose)
678 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
679 		return (0);
680 	}
681 	dumptime = dtime.tv_sec;
682 	if (dumptime == 0) {
683 		if (verbose)
684 			syslog(LOG_ERR, "dump time is zero");
685 		return (0);
686 	}
687 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
688 #define	LEEWAY	(7 * SECSPERDAY)
689 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
690 		(void)printf("dump time is unreasonable\n");
691 		return (0);
692 	}
693 	return (1);
694 }
695 
696 int
697 check_space(void)
698 {
699 	FILE *fp;
700 	off_t minfree, spacefree, kernelsize, needed;
701 	struct stat st;
702 	struct statfs fsbuf;
703 	char mbuf[100], path[MAXPATHLEN];
704 
705 #ifdef __GNUC__
706 	(void) &minfree;
707 #endif
708 
709 	if (stat(kernel, &st) < 0) {
710 		syslog(LOG_ERR, "%s: %m", kernel);
711 		exit(1);
712 	}
713 	kernelsize = st.st_blocks * S_BLKSIZE;
714 	if (statfs(dirname, &fsbuf) < 0) {
715 		syslog(LOG_ERR, "%s: %m", dirname);
716 		exit(1);
717 	}
718 	spacefree = fsbuf.f_bavail;
719 	spacefree *= fsbuf.f_bsize;
720 	spacefree /= 1024;
721 
722 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
723 	if ((fp = fopen(path, "r")) == NULL)
724 		minfree = 0;
725 	else {
726 		if (fgets(mbuf, sizeof(mbuf), fp) == NULL)
727 			minfree = 0;
728 		else
729 			minfree = atoi(mbuf);
730 		(void)fclose(fp);
731 	}
732 
733 	needed = (dumpsize + kernelsize) / 1024;
734  	if (minfree > 0 && spacefree - needed < minfree) {
735 		syslog(LOG_WARNING,
736 		    "no dump, not enough free space in %s", dirname);
737 		return (0);
738 	}
739 	if (spacefree - needed < minfree)
740 		syslog(LOG_WARNING,
741 		    "dump performed, but free space threshold crossed");
742 	return (1);
743 }
744 
745 int
746 Open(const char *name, int rw)
747 {
748 	int fd;
749 
750 	if ((fd = open(name, rw, 0)) < 0) {
751 		syslog(LOG_ERR, "%s: %m", name);
752 		exit(1);
753 	}
754 	return (fd);
755 }
756 
757 void
758 Lseek(int fd, off_t off, int flag)
759 {
760 	off_t ret;
761 
762 	ret = lseek(fd, off, flag);
763 	if (ret == -1) {
764 		syslog(LOG_ERR, "lseek: %m");
765 		exit(1);
766 	}
767 }
768 
769 int
770 Create(char *file, int mode)
771 {
772 	int fd;
773 
774 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
775 	if (fd < 0) {
776 		syslog(LOG_ERR, "%s: %m", file);
777 		exit(1);
778 	}
779 	return (fd);
780 }
781 
782 void
783 Write(int fd, void *bp, int size)
784 {
785 	int n;
786 
787 	if ((n = write(fd, bp, size)) < size) {
788 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
789 		exit(1);
790 	}
791 }
792 
793 void
794 usage(void)
795 {
796 	(void)syslog(LOG_ERR,
797 	    "usage: savecore [-cfvz] [-N system] [-Z level] directory");
798 	exit(1);
799 }
800