xref: /netbsd-src/sbin/savecore/savecore.c (revision 37b34d511dea595d3ba03a661cf3b775038ea5f8)
1 /*	$NetBSD: savecore.c,v 1.58 2002/09/27 18:38:53 drochner 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 1.58 2002/09/27 18:38:53 drochner 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	log(int, char *, ...);
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;
157 	char *ep;
158 
159 	dirname = NULL;
160 	kernel = NULL;
161 	level = 1;		/* default to fastest gzip compression */
162 	gzmode[0] = 'w';
163 
164 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
165 
166 	while ((ch = getopt(argc, argv, "cdfN:vzZ:")) != -1)
167 		switch(ch) {
168 		case 'c':
169 			clear = 1;
170 			break;
171 		case 'd':		/* Not documented. */
172 		case 'v':
173 			verbose = 1;
174 			break;
175 		case 'f':
176 			force = 1;
177 			break;
178 		case 'N':
179 			kernel = optarg;
180 			break;
181 		case 'z':
182 			compress = 1;
183 			break;
184 		case 'Z':
185 			level = (int)strtol(optarg, &ep, 10);
186 			if (level < 0 || level > 9) {
187 				(void)syslog(LOG_ERR, "invalid compression %s",
188 				    optarg);
189 				usage();
190 			}
191 			break;
192 		case '?':
193 		default:
194 			usage();
195 		}
196 	argc -= optind;
197 	argv += optind;
198 
199 	if (argc != (clear ? 0 : 1))
200 		usage();
201 
202 	gzmode[1] = level + '0';
203 	if (!clear)
204 		dirname = argv[0];
205 
206 	if (kernel == NULL) {
207 		kernel = getbootfile();
208 	}
209 
210 	(void)time(&now);
211 	kmem_setup();
212 
213 	if (clear) {
214 		clear_dump();
215 		exit(0);
216 	}
217 
218 	if (!dump_exists() && !force)
219 		exit(1);
220 
221 	check_kmem();
222 
223 	if (panicstr)
224 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
225 	else
226 		syslog(LOG_ALERT, "reboot");
227 
228 	if ((!get_crashtime() || !check_space()) && !force)
229 		exit(1);
230 
231 	save_core();
232 
233 	clear_dump();
234 	exit(0);
235 }
236 
237 void
238 kmem_setup(void)
239 {
240 	kvm_t *kd_kern;
241 	char errbuf[_POSIX2_LINE_MAX];
242 	int i, hdrsz;
243 
244 	/*
245 	 * Some names we need for the currently running system, others for
246 	 * the system that was running when the dump was made.  The values
247 	 * obtained from the current system are used to look for things in
248 	 * /dev/kmem that cannot be found in the kernel namelist, but are
249 	 * presumed to be the same (since the disk partitions are probably
250 	 * the same!)
251 	 */
252 	kd_kern = kvm_openfiles(kernel, NULL, NULL, O_RDONLY, errbuf);
253 	if (kd_kern == NULL) {
254 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
255 		exit(1);
256 	}
257 	if (kvm_nlist(kd_kern, current_nl) == -1)
258 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
259 		    kvm_geterr(kd_kern));
260 
261 	for (i = 0; cursyms[i] != -1; i++)
262 		if (current_nl[cursyms[i]].n_value == 0) {
263 			syslog(LOG_ERR, "%s: %s not in namelist",
264 			    kernel, current_nl[cursyms[i]].n_name);
265 			exit(1);
266 		}
267 
268 	if (KREAD(kd_kern, current_nl[X_DUMPDEV].n_value, &dumpdev) != 0) {
269 		if (verbose)
270 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
271 		exit(1);
272 	}
273 	if (dumpdev == NODEV) {
274 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
275 		exit(1);
276 	}
277 	{
278 	    long l_dumplo;
279 
280 	    if (KREAD(kd_kern, current_nl[X_DUMPLO].n_value, &l_dumplo) != 0) {
281 		    if (verbose)
282 			syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
283 		    exit(1);
284 	    }
285 	    if (l_dumplo == -1) {
286 		syslog(LOG_WARNING, "no core dump (invalid dumplo)");
287 		exit(1);
288 	    }
289 	    dumplo = DEV_BSIZE * (off_t) l_dumplo;
290 	}
291 
292 	if (verbose)
293 		(void)printf("dumplo = %lld (%ld * %ld)\n",
294 		    (long long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
295 	if (KREAD(kd_kern, current_nl[X_DUMPMAG].n_value, &dumpmag) != 0) {
296 		if (verbose)
297 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
298 		exit(1);
299 	}
300 
301 	(void)kvm_read(kd_kern, current_nl[X_VERSION].n_value, vers,
302 	    sizeof(vers));
303 	vers[sizeof(vers) - 1] = '\0';
304 
305 	ddname = find_dev(dumpdev, S_IFBLK);
306 	dumpfd = Open(ddname, O_RDWR);
307 
308 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
309 	if (kd_dump == NULL) {
310 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
311 		exit(1);
312 	}
313 
314 	if (kvm_nlist(kd_dump, dump_nl) == -1)
315 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
316 		    kvm_geterr(kd_dump));
317 
318 	for (i = 0; dumpsyms[i] != -1; i++)
319 		if (dump_nl[dumpsyms[i]].n_value == 0) {
320 			syslog(LOG_ERR, "%s: %s not in namelist",
321 			    kernel, dump_nl[dumpsyms[i]].n_name);
322 			exit(1);
323 		}
324 	hdrsz = kvm_dump_mkheader(kd_dump, dumplo);
325 
326 	/*
327 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
328 	 * checks, ergo no dump is present...
329 	 */
330 	if (hdrsz == 0) {
331 		syslog(LOG_WARNING, "no core dump");
332 		exit(1);
333 	}
334 	if (hdrsz == -1) {
335 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
336 		    kvm_geterr(kd_dump));
337 		exit(1);
338 	}
339 	dumplo += hdrsz;
340 	kvm_close(kd_kern);
341 }
342 
343 void
344 check_kmem(void)
345 {
346 	char *cp, *bufdata;
347 	struct kern_msgbuf msgbuf, *bufp;
348 	long panicloc, panicstart, panicend;
349 	char core_vers[1024];
350 
351 	(void)kvm_read(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
352 	    sizeof(core_vers));
353 	core_vers[sizeof(core_vers) - 1] = '\0';
354 
355 	if (strcmp(vers, core_vers) != 0)
356 		syslog(LOG_WARNING,
357 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
358 		    kernel, vers, core_vers);
359 
360 	panicstart = panicend = 0;
361 	if (KREAD(kd_dump, dump_nl[X_PANICSTART].n_value, &panicstart) != 0) {
362 		if (verbose)
363 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
364 		goto nomsguf;
365 	}
366 	if (KREAD(kd_dump, dump_nl[X_PANICEND].n_value, &panicend) != 0) {
367 		if (verbose)
368 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
369 		goto nomsguf;
370 	}
371 	if (panicstart != 0 && panicend != 0) {
372 		if (KREAD(kd_dump, dump_nl[X_MSGBUF].n_value, &bufp)) {
373 			if (verbose)
374 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
375 			goto nomsguf;
376 		}
377 		if (kvm_read(kd_dump, (long)bufp, &msgbuf,
378 		    offsetof(struct kern_msgbuf, msg_bufc)) !=
379 		    offsetof(struct kern_msgbuf, msg_bufc)) {
380 			if (verbose)
381 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
382 			goto nomsguf;
383 		}
384 		if (msgbuf.msg_magic != MSG_MAGIC) {
385 			if (verbose)
386 				syslog(LOG_WARNING, "msgbuf magic incorrect");
387 			goto nomsguf;
388 		}
389 		bufdata = malloc(msgbuf.msg_bufs);
390 		if (bufdata == NULL) {
391 			if (verbose)
392 				syslog(LOG_WARNING, "couldn't allocate space for msgbuf data");
393 			goto nomsguf;
394 		}
395 		if (kvm_read(kd_dump, (long)&bufp->msg_bufc, bufdata,
396 		    msgbuf.msg_bufs) != msgbuf.msg_bufs) {
397 			if (verbose)
398 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
399 			goto nomsguf;
400 		}
401 		cp = panic_mesg;
402 		while (panicstart != panicend && cp < &panic_mesg[sizeof(panic_mesg)-1]) {
403 			*cp++ = bufdata[panicstart];
404 			panicstart++;
405 			if (panicstart >= msgbuf.msg_bufs)
406 				panicstart = 0;
407 		}
408 		/* Don't end in a new-line */
409 		cp = &panic_mesg[strlen(panic_mesg)] - 1;
410 		if (*cp == '\n')
411 			*cp = '\0';
412 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
413 
414 		panicstr = 1;	/* anything not zero */
415 		return;
416 	}
417 nomsguf:
418 	if (KREAD(kd_dump, dump_nl[X_PANICSTR].n_value, &panicstr) != 0) {
419 		if (verbose)
420 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
421 		return;
422 	}
423 	if (panicstr) {
424 		cp = panic_mesg;
425 		panicloc = panicstr;
426 		do {
427 			if (KREAD(kd_dump, panicloc, cp) != 0) {
428 				if (verbose)
429 				    syslog(LOG_WARNING, "kvm_read: %s",
430 					kvm_geterr(kd_dump));
431 				break;
432 			}
433 			panicloc++;
434 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
435 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
436 	}
437 }
438 
439 int
440 dump_exists(void)
441 {
442 	u_int32_t newdumpmag;
443 
444 	if (KREAD(kd_dump, dump_nl[X_DUMPMAG].n_value, &newdumpmag) != 0) {
445 		if (verbose)
446 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
447 		return (0);
448 	}
449 
450 	/* Read the dump size. */
451 	if (KREAD(kd_dump, dump_nl[X_DUMPSIZE].n_value, &dumpsize) != 0) {
452 		if (verbose)
453 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
454 		return (0);
455 	}
456 	dumpsize *= getpagesize();
457 
458 	/*
459 	 * Return zero if core dump doesn't seem to be there, and note
460 	 * it for syslog.  This check and return happens after the dump size
461 	 * is read, so dumpsize is whether or not the core is valid (for -f).
462 	 */
463 	if (newdumpmag != dumpmag) {
464 		if (verbose)
465 			syslog(LOG_WARNING,
466 			    "magic number mismatch (0x%x != 0x%x)",
467 			    newdumpmag, dumpmag);
468 		syslog(LOG_WARNING, "no core dump");
469 		return (0);
470 	}
471 	return (1);
472 }
473 
474 void
475 clear_dump(void)
476 {
477 	if (kvm_dump_inval(kd_dump) == -1)
478 		syslog(LOG_ERR, "%s: kvm_clear_dump: %s", ddname,
479 		    kvm_geterr(kd_dump));
480 
481 }
482 
483 char buf[1024 * 1024];
484 
485 void
486 save_core(void)
487 {
488 	FILE *fp;
489 	int bounds, ifd, nr, nw, ofd;
490 	char *rawp, path[MAXPATHLEN];
491 
492 	ofd = -1;
493 	/*
494 	 * Get the current number and update the bounds file.  Do the update
495 	 * now, because may fail later and don't want to overwrite anything.
496 	 */
497 	umask(066);
498 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
499 	if ((fp = fopen(path, "r")) == NULL)
500 		goto err1;
501 	if (fgets(buf, sizeof(buf), fp) == NULL) {
502 		if (ferror(fp))
503 err1:			syslog(LOG_WARNING, "%s: %m", path);
504 		bounds = 0;
505 	} else
506 		bounds = atoi(buf);
507 	if (fp != NULL)
508 		(void)fclose(fp);
509 	if ((fp = fopen(path, "w")) == NULL)
510 		syslog(LOG_ERR, "%s: %m", path);
511 	else {
512 		(void)fprintf(fp, "%d\n", bounds + 1);
513 		(void)fclose(fp);
514 	}
515 
516 	/* Create the core file. */
517 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
518 	    dirname, bounds, compress ? ".gz" : "");
519 	if (compress) {
520 		if ((fp = zopen(path, gzmode)) == NULL) {
521 			syslog(LOG_ERR, "%s: %m", path);
522 			exit(1);
523 		}
524 	} else {
525 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
526 		fp  = fdopen(ofd, "w");
527 		if (fp == NULL) {
528 			syslog(LOG_ERR, "%s: fdopen: %m", path);
529 			exit(1);
530 		}
531 	}
532 
533 	/* Open the raw device. */
534 	rawp = rawname(ddname);
535 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
536 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
537 		ifd = dumpfd;
538 	}
539 
540 	/* Seek to the start of the core. */
541 	Lseek(ifd, dumplo, SEEK_SET);
542 
543 	if (kvm_dump_wrtheader(kd_dump, fp, dumpsize) == -1) {
544 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
545 		    kvm_geterr(kd_dump));
546 		exit(1);
547 	}
548 
549 	/* Copy the core file. */
550 	syslog(LOG_NOTICE, "writing %score to %s",
551 	    compress ? "compressed " : "", path);
552 	for (; dumpsize > 0; dumpsize -= nr) {
553 		char nbuf[7];
554 		humanize_number(nbuf, 7, dumpsize, "", HN_AUTOSCALE, 0);
555 		(void)printf("%7s\r", nbuf);
556 		(void)fflush(stdout);
557 		nr = read(ifd, buf, MIN(dumpsize, sizeof(buf)));
558 		if (nr <= 0) {
559 			if (nr == 0)
560 				syslog(LOG_WARNING,
561 				    "WARNING: EOF on dump device");
562 			else
563 				syslog(LOG_ERR, "%s: %m", rawp);
564 			goto err2;
565 		}
566 		nw = fwrite(buf, 1, nr, fp);
567 		if (nw != nr) {
568 			syslog(LOG_ERR, "%s: %s",
569 			    path, strerror(nw == 0 ? EIO : errno));
570 err2:			syslog(LOG_WARNING,
571 			    "WARNING: core may be incomplete");
572 			(void)printf("\n");
573 			exit(1);
574 		}
575 	}
576 	(void)close(ifd);
577 	(void)fclose(fp);
578 
579 	/* Copy the kernel. */
580 	ifd = Open(kernel, O_RDONLY);
581 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
582 	    dirname, bounds, compress ? ".gz" : "");
583 	if (compress) {
584 		if ((fp = zopen(path, gzmode)) == NULL) {
585 			syslog(LOG_ERR, "%s: %m", path);
586 			exit(1);
587 		}
588 	} else
589 		ofd = Create(path, S_IRUSR | S_IWUSR);
590 	syslog(LOG_NOTICE, "writing %skernel to %s",
591 	    compress ? "compressed " : "", path);
592 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
593 		if (compress)
594 			nw = fwrite(buf, 1, nr, fp);
595 		else
596 			nw = write(ofd, buf, nr);
597 		if (nw != nr) {
598 			syslog(LOG_ERR, "%s: %s",
599 			    path, strerror(nw == 0 ? EIO : errno));
600 			syslog(LOG_WARNING,
601 			    "WARNING: kernel may be incomplete");
602 			exit(1);
603 		}
604 	}
605 	if (nr < 0) {
606 		syslog(LOG_ERR, "%s: %m", kernel);
607 		syslog(LOG_WARNING, "WARNING: kernel may be incomplete");
608 		exit(1);
609 	}
610 	if (compress)
611 		(void)fclose(fp);
612 	else
613 		(void)close(ofd);
614 }
615 
616 char *
617 find_dev(dev_t dev, int type)
618 {
619 	DIR *dfd;
620 	struct dirent *dir;
621 	struct stat sb;
622 	char *dp, device[MAXPATHLEN + 1];
623 
624 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
625 		syslog(LOG_ERR, "%s: %m", _PATH_DEV);
626 		exit(1);
627 	}
628 	(void)strcpy(device, _PATH_DEV);
629 	while ((dir = readdir(dfd))) {
630 		(void)strcpy(device + sizeof(_PATH_DEV) - 1, dir->d_name);
631 		if (lstat(device, &sb)) {
632 			syslog(LOG_ERR, "%s: %m", device);
633 			continue;
634 		}
635 		if ((sb.st_mode & S_IFMT) != type)
636 			continue;
637 		if (dev == sb.st_rdev) {
638 			closedir(dfd);
639 			if ((dp = strdup(device)) == NULL) {
640 				syslog(LOG_ERR, "%m");
641 				exit(1);
642 			}
643 			return (dp);
644 		}
645 	}
646 	closedir(dfd);
647 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
648 	exit(1);
649 }
650 
651 char *
652 rawname(char *s)
653 {
654 	char *sl;
655 	char name[MAXPATHLEN];
656 
657 	if ((sl = strrchr(s, '/')) == NULL || sl[1] == '0') {
658 		syslog(LOG_ERR,
659 		    "can't make raw dump device name from %s", s);
660 		return (s);
661 	}
662 	(void)snprintf(name, sizeof(name), "%.*s/r%s", (int)(sl - s), s,
663 	    sl + 1);
664 	if ((sl = strdup(name)) == NULL) {
665 		syslog(LOG_ERR, "%m");
666 		exit(1);
667 	}
668 	return (sl);
669 }
670 
671 int
672 get_crashtime(void)
673 {
674 	struct timeval dtime;
675 	time_t dumptime;			/* Time the dump was taken. */
676 
677 	if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &dtime) != 0) {
678 		if (verbose)
679 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
680 		return (0);
681 	}
682 	dumptime = dtime.tv_sec;
683 	if (dumptime == 0) {
684 		if (verbose)
685 			syslog(LOG_ERR, "dump time is zero");
686 		return (0);
687 	}
688 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
689 #define	LEEWAY	(7 * SECSPERDAY)
690 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
691 		(void)printf("dump time is unreasonable\n");
692 		return (0);
693 	}
694 	return (1);
695 }
696 
697 int
698 check_space(void)
699 {
700 	FILE *fp;
701 	off_t minfree, spacefree, kernelsize, needed;
702 	struct stat st;
703 	struct statfs fsbuf;
704 	char mbuf[100], path[MAXPATHLEN];
705 
706 #ifdef __GNUC__
707 	(void) &minfree;
708 #endif
709 
710 	if (stat(kernel, &st) < 0) {
711 		syslog(LOG_ERR, "%s: %m", kernel);
712 		exit(1);
713 	}
714 	kernelsize = st.st_blocks * S_BLKSIZE;
715 	if (statfs(dirname, &fsbuf) < 0) {
716 		syslog(LOG_ERR, "%s: %m", dirname);
717 		exit(1);
718 	}
719 	spacefree = fsbuf.f_bavail;
720 	spacefree *= fsbuf.f_bsize;
721 	spacefree /= 1024;
722 
723 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
724 	if ((fp = fopen(path, "r")) == NULL)
725 		minfree = 0;
726 	else {
727 		if (fgets(mbuf, sizeof(mbuf), fp) == NULL)
728 			minfree = 0;
729 		else
730 			minfree = atoi(mbuf);
731 		(void)fclose(fp);
732 	}
733 
734 	needed = (dumpsize + kernelsize) / 1024;
735  	if (minfree > 0 && spacefree - needed < minfree) {
736 		syslog(LOG_WARNING,
737 		    "no dump, not enough free space in %s", dirname);
738 		return (0);
739 	}
740 	if (spacefree - needed < minfree)
741 		syslog(LOG_WARNING,
742 		    "dump performed, but free space threshold crossed");
743 	return (1);
744 }
745 
746 int
747 Open(const char *name, int rw)
748 {
749 	int fd;
750 
751 	if ((fd = open(name, rw, 0)) < 0) {
752 		syslog(LOG_ERR, "%s: %m", name);
753 		exit(1);
754 	}
755 	return (fd);
756 }
757 
758 void
759 Lseek(int fd, off_t off, int flag)
760 {
761 	off_t ret;
762 
763 	ret = lseek(fd, off, flag);
764 	if (ret == -1) {
765 		syslog(LOG_ERR, "lseek: %m");
766 		exit(1);
767 	}
768 }
769 
770 int
771 Create(char *file, int mode)
772 {
773 	int fd;
774 
775 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
776 	if (fd < 0) {
777 		syslog(LOG_ERR, "%s: %m", file);
778 		exit(1);
779 	}
780 	return (fd);
781 }
782 
783 void
784 Write(int fd, void *bp, int size)
785 {
786 	int n;
787 
788 	if ((n = write(fd, bp, size)) < size) {
789 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
790 		exit(1);
791 	}
792 }
793 
794 void
795 usage(void)
796 {
797 	(void)syslog(LOG_ERR,
798 	    "usage: savecore [-cfvz] [-N system] [-Z level] directory");
799 	exit(1);
800 }
801