xref: /netbsd-src/sbin/savecore/savecore.c (revision e6c7e151de239c49d2e38720a061ed9d1fa99309)
1 /*	$NetBSD: savecore.c,v 1.89 2019/11/06 07:29:08 mrg 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\
35  The Regents of the University of California.  All rights reserved.");
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 1.89 2019/11/06 07:29:08 mrg Exp $");
43 #endif
44 #endif /* not lint */
45 
46 #define _KSYMS_PRIVATE
47 
48 #include <stdbool.h>
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 #include <sys/ksyms.h>
56 
57 #include <dirent.h>
58 #include <errno.h>
59 #include <fcntl.h>
60 #include <nlist.h>
61 #include <paths.h>
62 #include <stddef.h>
63 #include <stdio.h>
64 #include <stdlib.h>
65 #include <string.h>
66 #include <time.h>
67 #include <tzfile.h>
68 #include <unistd.h>
69 #include <util.h>
70 #include <limits.h>
71 #include <stdarg.h>
72 #include <kvm.h>
73 
74 extern FILE *zopen(const char *fname, const char *mode);
75 
76 /*
77  * Note that KREAD_LOGWARN and KREAD_ERR take a variable name, not
78  * pointer to it, unlike KREAD() itself.
79  */
80 #define	KREAD(kd, addr, p)\
81 	(kvm_read(kd, addr, (char *)(p), sizeof(*(p))) != sizeof(*(p)))
82 #define KREAD_ERR(kd, addr, p, err)					\
83 do {									\
84 	if (KREAD(kd, addr, &(p)) != 0) {				\
85 		err;							\
86 	}								\
87 } while (0)
88 #define KREAD_LOGWARN(kd, addr, p, err)					\
89 do {									\
90 	if (KREAD(kd, addr, &(p)) != 0) {				\
91 		syslog(LOG_WARNING, "%s:%d: kvm_read " #p ": %s",	\
92 			__func__, __LINE__, kvm_geterr(kd));		\
93 		err;							\
94 	}								\
95 } while (0)
96 
97 static struct nlist current_nl[] = {	/* Namelist for currently running system. */
98 #define	X_DUMPDEV	0
99 	{ .n_name = "_dumpdev" },
100 #define	X_DUMPLO	1
101 	{ .n_name = "_dumplo" },
102 #define	X_TIME_SECOND	2
103 	{ .n_name = "_time_second" },
104 #define X_TIME		3
105 	{ .n_name = "_time" },
106 #define	X_DUMPSIZE	4
107 	{ .n_name = "_dumpsize" },
108 #define	X_VERSION	5
109 	{ .n_name = "_version" },
110 #define	X_DUMPMAG	6
111 	{ .n_name = "_dumpmag" },
112 #define	X_PANICSTR	7
113 	{ .n_name = "_panicstr" },
114 #define	X_PANICSTART	8
115 	{ .n_name = "_panicstart" },
116 #define	X_PANICEND	9
117 	{ .n_name = "_panicend" },
118 #define	X_MSGBUF	10
119 	{ .n_name = "_msgbufp" },
120 #define	X_DUMPCDEV	11
121 	{ .n_name = "_dumpcdev" },
122 #define X_SYMSZ		12
123 	{ .n_name = "_ksyms_symsz" },
124 #define X_STRSZ		13
125 	{ .n_name = "_ksyms_strsz" },
126 #define X_KHDR		14
127 	{ .n_name = "_ksyms_hdr" },
128 #define X_SYMTABS	15
129 	{ .n_name = "_ksyms_symtabs" },
130 	{ .n_name = NULL },
131 };
132 static int cursyms[] = { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, X_DUMPCDEV, -1 };
133 static int dumpsyms[] = { X_TIME_SECOND, X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR,
134     X_DUMPMAG, X_SYMSZ, X_STRSZ, X_KHDR, X_SYMTABS, -1 };
135 
136 static struct nlist dump_nl[] = {	/* Name list for dumped system. */
137 	{ .n_name = "_dumpdev" },	/* Entries MUST be the same as */
138 	{ .n_name = "_dumplo" },	/*	those in current_nl[].  */
139 	{ .n_name = "_time_second" },
140 	{ .n_name = "_time" },
141 	{ .n_name = "_dumpsize" },
142 	{ .n_name = "_version" },
143 	{ .n_name = "_dumpmag" },
144 	{ .n_name = "_panicstr" },
145 	{ .n_name = "_panicstart" },
146 	{ .n_name = "_panicend" },
147 	{ .n_name = "_msgbufp" },
148 	{ .n_name = "_dumpcdev" },
149 	{ .n_name = "_ksyms_symsz" },
150 	{ .n_name = "_ksyms_strsz" },
151 	{ .n_name = "_ksyms_hdr" },
152 	{ .n_name = "_ksyms_symtabs" },
153 	{ .n_name = NULL },
154 };
155 
156 /* Types match kernel declarations. */
157 static off_t	dumplo;				/* where dump starts on dumpdev */
158 static u_int32_t dumpmag;			/* magic number in dump */
159 static int	dumpsize;			/* amount of memory dumped */
160 static off_t dumpbytes;			/* in bytes */
161 
162 static const char	*kernel;		/* name of used kernel */
163 static const char	*dirname;		/* directory to save dumps in */
164 static char	*ddname;			/* name of dump device */
165 static dev_t	dumpdev;			/* dump device */
166 static dev_t	dumpcdev = NODEV;		/* dump device (char equivalent) */
167 static int	dumpfd;				/* read/write descriptor on dev */
168 static kvm_t	*kd_dump;			/* kvm descriptor on dev	*/
169 static time_t	now;				/* current date */
170 static char	panic_mesg[1024];
171 static long	panicstr;
172 static char	vers[1024];
173 static char	gzmode[3];
174 
175 static void	check_kmem(void);
176 static int	check_space(void);
177 static void	clear_dump(void);
178 static int	Create(char *, int);
179 static int	dump_exists(int);
180 static char	*find_dev(dev_t, mode_t);
181 static int	get_crashtime(void);
182 static void	kmem_setup(int);
183 static void	Lseek(int, off_t, int);
184 static int	Open(const char *, int rw);
185 static void	save_core(int);
186 __dead static void	usage(const char *fmt, ...) __printflike(1, 2);
187 
188 int
189 main(int argc, char *argv[])
190 {
191 	int ch, level, testonly, compress, force, clear, verbose;
192 	char *ep;
193 
194 	kernel = NULL;
195 	level = 1;		/* default to fastest gzip compression */
196 	force = 0;
197 	clear = 0;
198 	testonly = 0;
199 	verbose = 0;
200 	compress = 0;
201 	gzmode[0] = 'w';
202 
203 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
204 
205 	while ((ch = getopt(argc, argv, "cdfnN:vzZ:")) != -1)
206 		switch(ch) {
207 		case 'c':
208 			clear = 1;
209 			break;
210 		case 'd':		/* Not documented. */
211 		case 'v':
212 			verbose = 1;
213 			break;
214 		case 'f':
215 			force = 1;
216 			break;
217 		case 'n':
218 			testonly = 1;
219 			break;
220 		case 'N':
221 			kernel = optarg;
222 			break;
223 		case 'z':
224 			compress = 1;
225 			break;
226 		case 'Z':
227 			level = (int)strtol(optarg, &ep, 10);
228 			if (level < 0 || level > 9)
229 				usage("Invalid compression `%s'", optarg);
230 			break;
231 		case '?':
232 			usage("Missing argument for flag `%c'", optopt);
233 		default:
234 			usage("Unknown flag `%c'", ch);
235 		}
236 	argc -= optind;
237 	argv += optind;
238 
239 	if (argc != 0)
240 		dirname = argv[0];
241 	else
242 		dirname = "/var/crash";
243 
244 	gzmode[1] = level + '0';
245 
246 	(void)time(&now);
247 	kmem_setup(verbose);
248 
249 	if (clear && !testonly) {
250 		clear_dump();
251 		exit(0);
252 	}
253 
254 	if (!dump_exists(verbose) && !force)
255 		exit(1);
256 
257 	if (testonly)
258 		/* If -n was passed and there was a dump, exit at level 0 */
259 		exit(0);
260 
261 	check_kmem();
262 
263 	if (panicstr)
264 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
265 	else
266 		syslog(LOG_ALERT, "reboot");
267 
268 	if ((!get_crashtime() || !check_space()) && !force)
269 		exit(1);
270 
271 	save_core(compress);
272 
273 	clear_dump();
274 	exit(0);
275 }
276 
277 static void
278 kmem_setup(int verbose)
279 {
280 	long l_dumplo;
281 	kvm_t *kd_kern;
282 	char errbuf[_POSIX2_LINE_MAX];
283 	int i, hdrsz;
284 
285 	/*
286 	 * Some names we need for the currently running system, others for
287 	 * the system that was running when the dump was made.  The values
288 	 * obtained from the current system are used to look for things in
289 	 * /dev/kmem that cannot be found in the kernel namelist, but are
290 	 * presumed to be the same (since the disk partitions are probably
291 	 * the same!)
292 	 */
293 	kd_kern = kvm_openfiles(kernel, NULL, NULL, O_RDONLY, errbuf);
294 	if (kd_kern == NULL) {
295 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
296 		exit(1);
297 	}
298 	if (kvm_nlist(kd_kern, current_nl) == -1)
299 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
300 		    kvm_geterr(kd_kern));
301 
302 	for (i = 0; cursyms[i] != -1; i++) {
303 		if (current_nl[cursyms[i]].n_value != 0)
304 			continue;
305 		switch (cursyms[i]) {
306 		case X_TIME_SECOND:
307 		case X_TIME:
308 		case X_DUMPCDEV:
309 			break;
310 		default:
311 			syslog(LOG_ERR, "%s: %s not in namelist",
312 			    kernel, current_nl[cursyms[i]].n_name);
313 			exit(1);
314 		}
315 	}
316 
317 	KREAD_LOGWARN(kd_kern, current_nl[X_DUMPDEV].n_value, dumpdev, exit(1));
318 	if (dumpdev == NODEV) {
319 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
320 		exit(1);
321 	}
322 	KREAD_LOGWARN(kd_kern, current_nl[X_DUMPLO].n_value, l_dumplo, exit(1));
323 	if (l_dumplo == -1) {
324 		syslog(LOG_WARNING, "no core dump (invalid dumplo)");
325 		exit(1);
326 	}
327 	dumplo = DEV_BSIZE * (off_t) l_dumplo;
328 
329 	if (verbose)
330 		(void)printf("dumplo = %lld (%ld * %ld)\n",
331 		    (long long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
332 	KREAD_LOGWARN(kd_kern, current_nl[X_DUMPMAG].n_value, dumpmag, exit(1));
333 
334 	(void)kvm_read(kd_kern, current_nl[X_VERSION].n_value, vers,
335 	    sizeof(vers));
336 	vers[sizeof(vers) - 1] = '\0';
337 
338 	if (current_nl[X_DUMPCDEV].n_value != 0) {
339 		KREAD_LOGWARN(kd_kern, current_nl[X_DUMPCDEV].n_value, dumpcdev,
340 		    exit(1));
341 		ddname = find_dev(dumpcdev, S_IFCHR);
342 	} else
343 		ddname = find_dev(dumpdev, S_IFBLK);
344 	if (strncmp(ddname, "/dev/cons", 8) == 0 ||
345 	    strncmp(ddname, "/dev/tty", 7) == 0 ||
346 	    strncmp(ddname, "/dev/pty", 7) == 0 ||
347 	    strncmp(ddname, "/dev/pts", 7) == 0) {
348 		syslog(LOG_ERR, "dumpdev %s is tty; override kernel", ddname);
349 		exit(1);
350 	}
351 	dumpfd = Open(ddname, O_RDWR);
352 
353 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
354 	if (kd_dump == NULL) {
355 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
356 		exit(1);
357 	}
358 
359 	if (kvm_nlist(kd_dump, dump_nl) == -1)
360 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
361 		    kvm_geterr(kd_dump));
362 
363 	for (i = 0; dumpsyms[i] != -1; i++)
364 		if (dump_nl[dumpsyms[i]].n_value == 0 &&
365 			dumpsyms[i] != X_TIME_SECOND &&
366 			dumpsyms[i] != X_TIME) {
367 			syslog(LOG_ERR, "%s: %s not in namelist",
368 			    kernel, dump_nl[dumpsyms[i]].n_name);
369 			exit(1);
370 		}
371 	hdrsz = kvm_dump_mkheader(kd_dump, dumplo);
372 
373 	/*
374 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
375 	 * checks, ergo no dump is present...
376 	 */
377 	if (hdrsz == 0) {
378 		syslog(LOG_WARNING, "no core dump");
379 		exit(1);
380 	}
381 	if (hdrsz == -1) {
382 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
383 		    kvm_geterr(kd_dump));
384 		exit(1);
385 	}
386 	dumplo += hdrsz;
387 	kvm_close(kd_kern);
388 }
389 
390 static void
391 check_kmem(void)
392 {
393 	char *cp, *bufdata;
394 	struct kern_msgbuf msgbuf, *bufp;
395 	long panicloc, panicstart, panicend;
396 	char core_vers[1024];
397 
398 	(void)kvm_read(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
399 	    sizeof(core_vers));
400 	core_vers[sizeof(core_vers) - 1] = '\0';
401 
402 	if (strcmp(vers, core_vers) != 0)
403 		syslog(LOG_WARNING,
404 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
405 		    kvm_getkernelname(kd_dump), vers, core_vers);
406 
407 	panicstart = panicend = 0;
408 	KREAD_LOGWARN(kd_dump, dump_nl[X_PANICSTART].n_value, panicstart,
409 	    goto nomsguf);
410 	KREAD_LOGWARN(kd_dump, dump_nl[X_PANICEND].n_value, panicend,
411 	    goto nomsguf);
412 
413 	if (panicstart != 0 && panicend != 0) {
414 		KREAD_LOGWARN(kd_dump, dump_nl[X_MSGBUF].n_value, bufp,
415 		    goto nomsguf);
416 		/* Reads msg_bufs[1], but doesn't matter. */
417 		KREAD_LOGWARN(kd_dump, (long)bufp, msgbuf,
418 		    goto nomsguf);
419 		if (msgbuf.msg_magic != MSG_MAGIC) {
420 			syslog(LOG_WARNING, "msgbuf magic incorrect (%lx != %lx)",
421 			    msgbuf.msg_magic, (long)MSG_MAGIC);
422 			goto nomsguf;
423 		}
424 		bufdata = malloc(msgbuf.msg_bufs);
425 		if (bufdata == NULL) {
426 			syslog(LOG_WARNING, "couldn't allocate space for msgbuf data");
427 			goto nomsguf;
428 		}
429 		if (kvm_read(kd_dump, (long)&bufp->msg_bufc, bufdata,
430 		    msgbuf.msg_bufs) != msgbuf.msg_bufs) {
431 			syslog(LOG_WARNING, "kvm_read dmesg buffer: %s",
432 			    kvm_geterr(kd_dump));
433 			free(bufdata);
434 			goto nomsguf;
435 		}
436 		cp = panic_mesg;
437 		while (panicstart != panicend && cp < &panic_mesg[sizeof(panic_mesg)-1]) {
438 			*cp++ = bufdata[panicstart];
439 			panicstart++;
440 			if (panicstart >= msgbuf.msg_bufs)
441 				panicstart = 0;
442 		}
443 		/* Don't end in a new-line */
444 		cp = &panic_mesg[strlen(panic_mesg)] - 1;
445 		if (*cp == '\n')
446 			*cp = '\0';
447 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
448 		free(bufdata);
449 
450 		panicstr = 1;	/* anything not zero */
451 		return;
452 	}
453 nomsguf:
454 	KREAD_LOGWARN(kd_dump, dump_nl[X_PANICSTR].n_value, panicstr,
455 	    return);
456 	if (panicstr) {
457 		cp = panic_mesg;
458 		panicloc = panicstr;
459 		do {
460 			if (KREAD(kd_dump, panicloc, cp) != 0) {
461 				syslog(LOG_WARNING, "kvm_read msgbuf: %s",
462 				    kvm_geterr(kd_dump));
463 				break;
464 			}
465 			panicloc++;
466 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
467 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
468 	}
469 }
470 
471 static int
472 dump_exists(int verbose)
473 {
474 	u_int32_t newdumpmag;
475 
476 	/* Read the dump magic and size. */
477 	KREAD_ERR(kd_dump, dump_nl[X_DUMPMAG].n_value, newdumpmag, return 0);
478 	KREAD_ERR(kd_dump, dump_nl[X_DUMPSIZE].n_value, dumpsize, return 0);
479 
480 	dumpbytes = (off_t)dumpsize * getpagesize();
481 
482 	/*
483 	 * Return zero if core dump doesn't seem to be there, and note
484 	 * it for syslog.  This check and return happens after the dump size
485 	 * is read, so dumpsize is whether or not the core is valid (for -f).
486 	 */
487 	if (newdumpmag != dumpmag) {
488 		if (verbose)
489 			syslog(LOG_WARNING, "magic number mismatch "
490 			    "(%#x != %#x)", newdumpmag, dumpmag);
491 		syslog(LOG_WARNING, "no core dump");
492 		return (0);
493 	}
494 	return (1);
495 }
496 
497 static void
498 clear_dump(void)
499 {
500 	if (kvm_dump_inval(kd_dump) == -1)
501 		syslog(LOG_ERR, "%s: kvm_dump_inval: %s", ddname,
502 		    kvm_geterr(kd_dump));
503 
504 }
505 
506 static char buf[1024 * 1024];
507 
508 static void
509 save_kernel(FILE *fp, char *path)
510 {
511 	int nw, nr, ifd;
512 
513 	ifd = Open(kernel, O_RDONLY);
514 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
515 		nw = fwrite(buf, 1, nr, fp);
516 		if (nw != nr) {
517 			syslog(LOG_ERR, "%s: %s",
518 			    path, strerror(nw == 0 ? EIO : errno));
519 			syslog(LOG_WARNING,
520 			    "WARNING: kernel may be incomplete");
521 			exit(1);
522 		}
523 	}
524 	if (nr < 0) {
525 		syslog(LOG_ERR, "%s: %m", kernel);
526 		syslog(LOG_WARNING, "WARNING: kernel may be incomplete");
527 		exit(1);
528 	}
529 }
530 
531 static int
532 ksymsget(u_long addr, void *ptr, size_t size)
533 {
534 
535 	if ((size_t)kvm_read(kd_dump, addr, ptr, size) != size) {
536 		syslog(LOG_WARNING, "kvm_read ksyms: %s", kvm_geterr(kd_dump));
537 		return 1;
538 	}
539 	return 0;
540 }
541 
542 static int
543 save_ksyms(FILE *fp, char *path)
544 {
545 	struct ksyms_hdr khdr;
546 	int nw, symsz, strsz;
547 	TAILQ_HEAD(, ksyms_symtab) symtabs;
548 	struct ksyms_symtab st, *stptr;
549 	void *p;
550 
551 	/* Get basic info and ELF headers, check if ksyms was on. */
552 	if (ksymsget(dump_nl[X_KHDR].n_value, &khdr, sizeof(khdr)))
553 		return 1;
554 	if (ksymsget(dump_nl[X_SYMSZ].n_value, &symsz, sizeof(symsz)))
555 		return 1;
556 	if (ksymsget(dump_nl[X_STRSZ].n_value, &strsz, sizeof(strsz)))
557 		return 1;
558 	if (symsz == 0 || strsz == 0)
559 		return 1;
560 
561 	/* Update the ELF section headers for symbols/strings. */
562 	khdr.kh_shdr[SYMTAB].sh_size = symsz;
563 	khdr.kh_shdr[SYMTAB].sh_info = symsz / sizeof(Elf_Sym);
564 	khdr.kh_shdr[STRTAB].sh_offset = symsz +
565 	    khdr.kh_shdr[SYMTAB].sh_offset;
566 	khdr.kh_shdr[STRTAB].sh_size = strsz;
567 
568 	/* Write out the ELF headers. */
569 	nw = fwrite(&khdr, 1, sizeof(khdr), fp);
570 	if (nw != sizeof(khdr)) {
571 		syslog(LOG_ERR, "%s: %s",
572 		    path, strerror(nw == 0 ? EIO : errno));
573 		syslog(LOG_WARNING,
574 		    "WARNING: kernel may be incomplete");
575 		exit(1);
576         }
577 
578         /* Dump symbol table. */
579 	if (ksymsget(dump_nl[X_SYMTABS].n_value, &symtabs, sizeof(symtabs)))
580 		return 1;
581 	stptr = TAILQ_FIRST(&symtabs);
582 	while (stptr != NULL) {
583 		if (ksymsget((u_long)stptr, &st, sizeof(st)))
584 			return 1;
585 		stptr = TAILQ_NEXT(&st, sd_queue);
586 		if ((p = malloc(st.sd_symsize)) == NULL)
587 			return 1;
588 		if (ksymsget((u_long)st.sd_symstart, p, st.sd_symsize)) {
589 			free(p);
590 			return 1;
591 		}
592 		nw = fwrite(p, 1, st.sd_symsize, fp);
593 		free(p);
594 		if (nw != st.sd_symsize) {
595 			syslog(LOG_ERR, "%s: %s",
596 			    path, strerror(nw == 0 ? EIO : errno));
597 			syslog(LOG_WARNING,
598 			    "WARNING: kernel may be incomplete");
599 			exit(1);
600 		}
601 	}
602 
603 	/* Dump string table. */
604 	if (ksymsget(dump_nl[X_SYMTABS].n_value, &symtabs, sizeof(symtabs)))
605 		return 1;
606 	stptr = TAILQ_FIRST(&symtabs);
607 	while (stptr != NULL) {
608 		if (ksymsget((u_long)stptr, &st, sizeof(st)))
609 			return 1;
610 		stptr = TAILQ_NEXT(&st, sd_queue);
611 		if ((p = malloc(st.sd_symsize)) == NULL)
612 			return 1;
613 		if (ksymsget((u_long)st.sd_strstart, p, st.sd_strsize)) {
614 			free(p);
615 			return 1;
616 		}
617 		nw = fwrite(p, 1, st.sd_strsize, fp);
618 		free(p);
619 		if (nw != st.sd_strsize) {
620 			syslog(LOG_ERR, "%s: %s",
621 			    path, strerror(nw == 0 ? EIO : errno));
622 			syslog(LOG_WARNING,
623 			    "WARNING: kernel may be incomplete");
624 			exit(1);
625 		}
626 	}
627 
628 	return 0;
629 }
630 
631 static void
632 save_core(int compress)
633 {
634 	FILE *fp;
635 	int bounds, ifd, nr, nw, ofd, tryksyms;
636 	char path[MAXPATHLEN], rbuf[MAXPATHLEN];
637 	const char *rawp;
638 
639 	ofd = -1;
640 	/*
641 	 * Get the current number and update the bounds file.  Do the update
642 	 * now, because may fail later and don't want to overwrite anything.
643 	 */
644 	umask(066);
645 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
646 	if ((fp = fopen(path, "r")) == NULL)
647 		goto err1;
648 	if (fgets(buf, sizeof(buf), fp) == NULL) {
649 		if (ferror(fp))
650 err1:			syslog(LOG_WARNING, "%s: %m", path);
651 		bounds = 0;
652 	} else
653 		bounds = atoi(buf);
654 	if (fp != NULL)
655 		(void)fclose(fp);
656 	if ((fp = fopen(path, "w")) == NULL)
657 		syslog(LOG_ERR, "%s: %m", path);
658 	else {
659 		(void)fprintf(fp, "%d\n", bounds + 1);
660 		(void)fclose(fp);
661 	}
662 
663 	/* Create the core file. */
664 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
665 	    dirname, bounds, compress ? ".gz" : "");
666 	if (compress) {
667 		if ((fp = zopen(path, gzmode)) == NULL) {
668 			syslog(LOG_ERR, "%s: %m", path);
669 			exit(1);
670 		}
671 	} else {
672 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
673 		fp  = fdopen(ofd, "w");
674 		if (fp == NULL) {
675 			syslog(LOG_ERR, "%s: fdopen: %m", path);
676 			exit(1);
677 		}
678 	}
679 
680 	if (dumpcdev == NODEV) {
681 		/* Open the raw device. */
682 		rawp = getdiskrawname(rbuf, sizeof(rbuf), ddname);
683 		if (rawp == NULL) {
684 			syslog(LOG_WARNING, "%s: %m; can't convert to raw",
685 			    ddname);
686 			rawp = ddname;
687 		}
688 		if ((ifd = open(rawp, O_RDONLY)) == -1) {
689 			syslog(LOG_WARNING, "%s: %m; using block device",
690 			    rawp);
691 			ifd = dumpfd;
692 		}
693 	} else {
694 		rawp = ddname;
695 		ifd = dumpfd;
696 	}
697 
698 	/* Seek to the start of the core. */
699 	Lseek(ifd, dumplo, SEEK_SET);
700 
701 	if (kvm_dump_wrtheader(kd_dump, fp, (int32_t)dumpbytes) == -1) {
702 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
703 		    kvm_geterr(kd_dump));
704 		exit(1);
705 	}
706 
707 	/* Copy the core file. */
708 	syslog(LOG_NOTICE, "writing %score to %s",
709 	    compress ? "compressed " : "", path);
710 	for (; dumpbytes > (off_t)0; dumpbytes -= (off_t)nr) {
711 		char nbuf[7];
712 		humanize_number(nbuf, 7, dumpbytes, "", HN_AUTOSCALE, 0);
713 		(void)printf("%7s\r", nbuf);
714 		(void)fflush(stdout);
715 		nr = read(ifd, buf, MIN(dumpbytes, (off_t)sizeof(buf)));
716 		if (nr <= 0) {
717 			if (nr == 0)
718 				syslog(LOG_WARNING,
719 				    "WARNING: EOF on dump device");
720 			else
721 				syslog(LOG_ERR, "%s: %m", rawp);
722 			goto err2;
723 		}
724 		nw = fwrite(buf, 1, nr, fp);
725 		if (nw != nr) {
726 			syslog(LOG_ERR, "%s: %s",
727 			    path, strerror(nw == 0 ? EIO : errno));
728 err2:			syslog(LOG_WARNING,
729 			    "WARNING: core may be incomplete");
730 			(void)printf("\n");
731 			exit(1);
732 		}
733 	}
734 	if (dumpcdev == NODEV)
735 		(void)close(ifd);
736 	(void)fclose(fp);
737 
738 	/* Create a kernel. */
739 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
740 	    dirname, bounds, compress ? ".gz" : "");
741 	syslog(LOG_NOTICE, "writing %skernel to %s",
742 	    compress ? "compressed " : "", path);
743 	for (tryksyms = 1;; tryksyms = 0) {
744 		if (compress) {
745 			if ((fp = zopen(path, gzmode)) == NULL) {
746 				syslog(LOG_ERR, "%s: %m", path);
747 				exit(1);
748 			}
749 		} else {
750 			ofd = Create(path, S_IRUSR | S_IWUSR);
751 			fp  = fdopen(ofd, "w");
752 			if (fp == NULL) {
753 				syslog(LOG_ERR, "fdopen: %m");
754 				exit(1);
755 			}
756 		}
757 		if (tryksyms) {
758 			if (!save_ksyms(fp, path))
759 				break;
760 			(void)fclose(fp);
761 			unlink(path);
762 		} else {
763 			save_kernel(fp, path);
764 			break;
765 		}
766 	}
767 	(void)fclose(fp);
768 
769 	/*
770 	 * For development systems where the crash occurs during boot
771 	 * to multiuser.
772 	 */
773 	sync();
774 	sleep(1);
775 	sync();
776 	sleep(1);
777 }
778 
779 static char *
780 find_dev(dev_t dev, mode_t type)
781 {
782 	DIR *dfd;
783 	struct dirent *dir;
784 	struct stat sb;
785 	char *dp, device[MAXPATHLEN + 1], *p;
786 	size_t l;
787 
788 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
789 		syslog(LOG_ERR, "%s: %m", _PATH_DEV);
790 		exit(1);
791 	}
792 	strlcpy(device, _PATH_DEV, sizeof(device));
793 	p = &device[strlen(device)];
794 	l = sizeof(device) - strlen(device);
795 	while ((dir = readdir(dfd))) {
796 		strlcpy(p, dir->d_name, l);
797 		if (lstat(device, &sb)) {
798 			syslog(LOG_ERR, "%s: %m", device);
799 			continue;
800 		}
801 		if ((sb.st_mode & S_IFMT) != type)
802 			continue;
803 		if (dev == sb.st_rdev) {
804 			closedir(dfd);
805 			if ((dp = strdup(device)) == NULL) {
806 				syslog(LOG_ERR, "%m");
807 				exit(1);
808 			}
809 			return (dp);
810 		}
811 	}
812 	closedir(dfd);
813 	syslog(LOG_ERR, "can't find device %lld/%lld",
814 	    (long long)major(dev), (long long)minor(dev));
815 	exit(1);
816 }
817 
818 static int
819 get_crashtime(void)
820 {
821 	time_t dumptime;			/* Time the dump was taken. */
822 	struct timeval dtime;
823 
824 	if (KREAD(kd_dump, dump_nl[X_TIME_SECOND].n_value, &dumptime) != 0) {
825 		if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &dtime) != 0) {
826 			syslog(LOG_WARNING, "kvm_read dumptime: %s (and _time_second "
827 			    "is not defined also)", kvm_geterr(kd_dump));
828 			return (0);
829 		}
830 		dumptime = dtime.tv_sec;
831 	}
832 	if (dumptime == 0) {
833 		syslog(LOG_WARNING, "dump time is zero");
834 		return (0);
835 	}
836 	syslog(LOG_INFO, "system went down at %s", ctime(&dumptime));
837 #define	LEEWAY	(60 * SECSPERDAY)
838 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
839 		syslog(LOG_WARNING, "dump time is unreasonable");
840 		return (0);
841 	}
842 	return (1);
843 }
844 
845 static int
846 check_space(void)
847 {
848 	FILE *fp;
849 	off_t minfree, spacefree, kernelsize, needed;
850 	struct stat st;
851 	struct statvfs fsbuf;
852 	char mbuf[100], path[MAXPATHLEN];
853 
854 	/* XXX assume a reasonable default, unless we find a kernel. */
855 	kernelsize = 20 * 1024 * 1024;
856 	if (!stat(kernel, &st)) kernelsize = st.st_blocks * S_BLKSIZE;
857 	if (statvfs(dirname, &fsbuf) < 0) {
858 		syslog(LOG_ERR, "%s: %m", dirname);
859 		exit(1);
860 	}
861 	spacefree = fsbuf.f_bavail;
862 	spacefree *= fsbuf.f_frsize;
863 	spacefree /= 1024;
864 
865 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
866 	if ((fp = fopen(path, "r")) == NULL)
867 		minfree = 0;
868 	else {
869 		if (fgets(mbuf, sizeof(mbuf), fp) == NULL)
870 			minfree = 0;
871 		else
872 			minfree = atoi(mbuf);
873 		(void)fclose(fp);
874 	}
875 
876 	needed = (dumpbytes + kernelsize) / 1024;
877  	if (minfree > 0 && spacefree - needed < minfree) {
878 		syslog(LOG_WARNING,
879 		    "no dump, not enough free space in %s", dirname);
880 		return (0);
881 	}
882 	if (spacefree - needed < minfree)
883 		syslog(LOG_WARNING,
884 		    "dump performed, but free space threshold crossed");
885 	return (1);
886 }
887 
888 static int
889 Open(const char *name, int rw)
890 {
891 	int fd;
892 
893 	if ((fd = open(name, rw, 0)) < 0) {
894 		syslog(LOG_ERR, "%s: %m", name);
895 		exit(1);
896 	}
897 	return (fd);
898 }
899 
900 static void
901 Lseek(int fd, off_t off, int flag)
902 {
903 	off_t ret;
904 
905 	ret = lseek(fd, off, flag);
906 	if (ret == -1) {
907 		syslog(LOG_ERR, "lseek: %m");
908 		exit(1);
909 	}
910 }
911 
912 static int
913 Create(char *file, int mode)
914 {
915 	int fd;
916 
917 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
918 	if (fd < 0) {
919 		syslog(LOG_ERR, "%s: %m", file);
920 		exit(1);
921 	}
922 	return (fd);
923 }
924 
925 static void
926 usage(const char *fmt, ...)
927 {
928 	va_list ap;
929 	va_start(ap, fmt);
930 	(void)vsyslog(LOG_ERR, fmt, ap);
931 	va_end(ap);
932 	(void)syslog(LOG_ERR,
933 	    "Usage: %s [-cfnvz] [-N system] [-Z level] [directory]",
934 	    getprogname());
935 	exit(1);
936 }
937