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      1 /*	$NetBSD: savecore.c,v 1.90 2020/04/03 19:09:43 maxv 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 1.90 2020/04/03 19:09:43 maxv 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 read_string(kvm_t *kd, u_long kva, char *buf, size_t size)
    279 {
    280 	size_t i;
    281 
    282 	for (i = 0; i < size - 1; i++) {
    283 		(void)kvm_read(kd, kva + i, buf + i, 1);
    284 		if (buf[i] == '\0')
    285 			return;
    286 	}
    287 
    288 	buf[size - 1] = '\0';
    289 }
    290 
    291 static void
    292 kmem_setup(int verbose)
    293 {
    294 	long l_dumplo;
    295 	kvm_t *kd_kern;
    296 	char errbuf[_POSIX2_LINE_MAX];
    297 	int i, hdrsz;
    298 
    299 	/*
    300 	 * Some names we need for the currently running system, others for
    301 	 * the system that was running when the dump was made.  The values
    302 	 * obtained from the current system are used to look for things in
    303 	 * /dev/kmem that cannot be found in the kernel namelist, but are
    304 	 * presumed to be the same (since the disk partitions are probably
    305 	 * the same!)
    306 	 */
    307 	kd_kern = kvm_openfiles(kernel, NULL, NULL, O_RDONLY, errbuf);
    308 	if (kd_kern == NULL) {
    309 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    310 		exit(1);
    311 	}
    312 	if (kvm_nlist(kd_kern, current_nl) == -1)
    313 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    314 		    kvm_geterr(kd_kern));
    315 
    316 	for (i = 0; cursyms[i] != -1; i++) {
    317 		if (current_nl[cursyms[i]].n_value != 0)
    318 			continue;
    319 		switch (cursyms[i]) {
    320 		case X_TIME_SECOND:
    321 		case X_TIME:
    322 		case X_DUMPCDEV:
    323 			break;
    324 		default:
    325 			syslog(LOG_ERR, "%s: %s not in namelist",
    326 			    kernel, current_nl[cursyms[i]].n_name);
    327 			exit(1);
    328 		}
    329 	}
    330 
    331 	KREAD_LOGWARN(kd_kern, current_nl[X_DUMPDEV].n_value, dumpdev, exit(1));
    332 	if (dumpdev == NODEV) {
    333 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
    334 		exit(1);
    335 	}
    336 	KREAD_LOGWARN(kd_kern, current_nl[X_DUMPLO].n_value, l_dumplo, exit(1));
    337 	if (l_dumplo == -1) {
    338 		syslog(LOG_WARNING, "no core dump (invalid dumplo)");
    339 		exit(1);
    340 	}
    341 	dumplo = DEV_BSIZE * (off_t) l_dumplo;
    342 
    343 	if (verbose)
    344 		(void)printf("dumplo = %lld (%ld * %ld)\n",
    345 		    (long long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
    346 	KREAD_LOGWARN(kd_kern, current_nl[X_DUMPMAG].n_value, dumpmag, exit(1));
    347 
    348 	read_string(kd_kern, current_nl[X_VERSION].n_value, vers,
    349 	    sizeof(vers));
    350 
    351 	if (current_nl[X_DUMPCDEV].n_value != 0) {
    352 		KREAD_LOGWARN(kd_kern, current_nl[X_DUMPCDEV].n_value, dumpcdev,
    353 		    exit(1));
    354 		ddname = find_dev(dumpcdev, S_IFCHR);
    355 	} else
    356 		ddname = find_dev(dumpdev, S_IFBLK);
    357 	if (strncmp(ddname, "/dev/cons", 8) == 0 ||
    358 	    strncmp(ddname, "/dev/tty", 7) == 0 ||
    359 	    strncmp(ddname, "/dev/pty", 7) == 0 ||
    360 	    strncmp(ddname, "/dev/pts", 7) == 0) {
    361 		syslog(LOG_ERR, "dumpdev %s is tty; override kernel", ddname);
    362 		exit(1);
    363 	}
    364 	dumpfd = Open(ddname, O_RDWR);
    365 
    366 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
    367 	if (kd_dump == NULL) {
    368 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    369 		exit(1);
    370 	}
    371 
    372 	if (kvm_nlist(kd_dump, dump_nl) == -1)
    373 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    374 		    kvm_geterr(kd_dump));
    375 
    376 	for (i = 0; dumpsyms[i] != -1; i++)
    377 		if (dump_nl[dumpsyms[i]].n_value == 0 &&
    378 			dumpsyms[i] != X_TIME_SECOND &&
    379 			dumpsyms[i] != X_TIME) {
    380 			syslog(LOG_ERR, "%s: %s not in namelist",
    381 			    kernel, dump_nl[dumpsyms[i]].n_name);
    382 			exit(1);
    383 		}
    384 	hdrsz = kvm_dump_mkheader(kd_dump, dumplo);
    385 
    386 	/*
    387 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
    388 	 * checks, ergo no dump is present...
    389 	 */
    390 	if (hdrsz == 0) {
    391 		syslog(LOG_WARNING, "no core dump");
    392 		exit(1);
    393 	}
    394 	if (hdrsz == -1) {
    395 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
    396 		    kvm_geterr(kd_dump));
    397 		exit(1);
    398 	}
    399 	dumplo += hdrsz;
    400 	kvm_close(kd_kern);
    401 }
    402 
    403 static void
    404 check_kmem(void)
    405 {
    406 	char *cp, *bufdata;
    407 	struct kern_msgbuf msgbuf, *bufp;
    408 	long panicloc, panicstart, panicend;
    409 	char core_vers[1024];
    410 
    411 	read_string(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
    412 	    sizeof(core_vers));
    413 
    414 	if (strcmp(vers, core_vers) != 0)
    415 		syslog(LOG_WARNING,
    416 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
    417 		    kvm_getkernelname(kd_dump), vers, core_vers);
    418 
    419 	panicstart = panicend = 0;
    420 	KREAD_LOGWARN(kd_dump, dump_nl[X_PANICSTART].n_value, panicstart,
    421 	    goto nomsguf);
    422 	KREAD_LOGWARN(kd_dump, dump_nl[X_PANICEND].n_value, panicend,
    423 	    goto nomsguf);
    424 
    425 	if (panicstart != 0 && panicend != 0) {
    426 		KREAD_LOGWARN(kd_dump, dump_nl[X_MSGBUF].n_value, bufp,
    427 		    goto nomsguf);
    428 		/* Reads msg_bufs[1], but doesn't matter. */
    429 		KREAD_LOGWARN(kd_dump, (long)bufp, msgbuf,
    430 		    goto nomsguf);
    431 		if (msgbuf.msg_magic != MSG_MAGIC) {
    432 			syslog(LOG_WARNING, "msgbuf magic incorrect (%lx != %lx)",
    433 			    msgbuf.msg_magic, (long)MSG_MAGIC);
    434 			goto nomsguf;
    435 		}
    436 		bufdata = malloc(msgbuf.msg_bufs);
    437 		if (bufdata == NULL) {
    438 			syslog(LOG_WARNING, "couldn't allocate space for msgbuf data");
    439 			goto nomsguf;
    440 		}
    441 		if (kvm_read(kd_dump, (long)&bufp->msg_bufc, bufdata,
    442 		    msgbuf.msg_bufs) != msgbuf.msg_bufs) {
    443 			syslog(LOG_WARNING, "kvm_read dmesg buffer: %s",
    444 			    kvm_geterr(kd_dump));
    445 			free(bufdata);
    446 			goto nomsguf;
    447 		}
    448 		cp = panic_mesg;
    449 		while (panicstart != panicend && cp < &panic_mesg[sizeof(panic_mesg)-1]) {
    450 			*cp++ = bufdata[panicstart];
    451 			panicstart++;
    452 			if (panicstart >= msgbuf.msg_bufs)
    453 				panicstart = 0;
    454 		}
    455 		/* Don't end in a new-line */
    456 		cp = &panic_mesg[strlen(panic_mesg)] - 1;
    457 		if (*cp == '\n')
    458 			*cp = '\0';
    459 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
    460 		free(bufdata);
    461 
    462 		panicstr = 1;	/* anything not zero */
    463 		return;
    464 	}
    465 nomsguf:
    466 	KREAD_LOGWARN(kd_dump, dump_nl[X_PANICSTR].n_value, panicstr,
    467 	    return);
    468 	if (panicstr) {
    469 		cp = panic_mesg;
    470 		panicloc = panicstr;
    471 		do {
    472 			if (KREAD(kd_dump, panicloc, cp) != 0) {
    473 				syslog(LOG_WARNING, "kvm_read msgbuf: %s",
    474 				    kvm_geterr(kd_dump));
    475 				break;
    476 			}
    477 			panicloc++;
    478 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
    479 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
    480 	}
    481 }
    482 
    483 static int
    484 dump_exists(int verbose)
    485 {
    486 	u_int32_t newdumpmag;
    487 
    488 	/* Read the dump magic and size. */
    489 	KREAD_ERR(kd_dump, dump_nl[X_DUMPMAG].n_value, newdumpmag, return 0);
    490 	KREAD_ERR(kd_dump, dump_nl[X_DUMPSIZE].n_value, dumpsize, return 0);
    491 
    492 	dumpbytes = (off_t)dumpsize * getpagesize();
    493 
    494 	/*
    495 	 * Return zero if core dump doesn't seem to be there, and note
    496 	 * it for syslog.  This check and return happens after the dump size
    497 	 * is read, so dumpsize is whether or not the core is valid (for -f).
    498 	 */
    499 	if (newdumpmag != dumpmag) {
    500 		if (verbose)
    501 			syslog(LOG_WARNING, "magic number mismatch "
    502 			    "(%#x != %#x)", newdumpmag, dumpmag);
    503 		syslog(LOG_WARNING, "no core dump");
    504 		return (0);
    505 	}
    506 	return (1);
    507 }
    508 
    509 static void
    510 clear_dump(void)
    511 {
    512 	if (kvm_dump_inval(kd_dump) == -1)
    513 		syslog(LOG_ERR, "%s: kvm_dump_inval: %s", ddname,
    514 		    kvm_geterr(kd_dump));
    515 
    516 }
    517 
    518 static char buf[1024 * 1024];
    519 
    520 static void
    521 save_kernel(FILE *fp, char *path)
    522 {
    523 	int nw, nr, ifd;
    524 
    525 	ifd = Open(kernel, O_RDONLY);
    526 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
    527 		nw = fwrite(buf, 1, nr, fp);
    528 		if (nw != nr) {
    529 			syslog(LOG_ERR, "%s: %s",
    530 			    path, strerror(nw == 0 ? EIO : errno));
    531 			syslog(LOG_WARNING,
    532 			    "WARNING: kernel may be incomplete");
    533 			exit(1);
    534 		}
    535 	}
    536 	if (nr < 0) {
    537 		syslog(LOG_ERR, "%s: %m", kernel);
    538 		syslog(LOG_WARNING, "WARNING: kernel may be incomplete");
    539 		exit(1);
    540 	}
    541 }
    542 
    543 static int
    544 ksymsget(u_long addr, void *ptr, size_t size)
    545 {
    546 
    547 	if ((size_t)kvm_read(kd_dump, addr, ptr, size) != size) {
    548 		syslog(LOG_WARNING, "kvm_read ksyms: %s", kvm_geterr(kd_dump));
    549 		return 1;
    550 	}
    551 	return 0;
    552 }
    553 
    554 static int
    555 save_ksyms(FILE *fp, char *path)
    556 {
    557 	struct ksyms_hdr khdr;
    558 	int nw, symsz, strsz;
    559 	TAILQ_HEAD(, ksyms_symtab) symtabs;
    560 	struct ksyms_symtab st, *stptr;
    561 	void *p;
    562 
    563 	/* Get basic info and ELF headers, check if ksyms was on. */
    564 	if (ksymsget(dump_nl[X_KHDR].n_value, &khdr, sizeof(khdr)))
    565 		return 1;
    566 	if (ksymsget(dump_nl[X_SYMSZ].n_value, &symsz, sizeof(symsz)))
    567 		return 1;
    568 	if (ksymsget(dump_nl[X_STRSZ].n_value, &strsz, sizeof(strsz)))
    569 		return 1;
    570 	if (symsz == 0 || strsz == 0)
    571 		return 1;
    572 
    573 	/* Update the ELF section headers for symbols/strings. */
    574 	khdr.kh_shdr[SYMTAB].sh_size = symsz;
    575 	khdr.kh_shdr[SYMTAB].sh_info = symsz / sizeof(Elf_Sym);
    576 	khdr.kh_shdr[STRTAB].sh_offset = symsz +
    577 	    khdr.kh_shdr[SYMTAB].sh_offset;
    578 	khdr.kh_shdr[STRTAB].sh_size = strsz;
    579 
    580 	/* Write out the ELF headers. */
    581 	nw = fwrite(&khdr, 1, sizeof(khdr), fp);
    582 	if (nw != sizeof(khdr)) {
    583 		syslog(LOG_ERR, "%s: %s",
    584 		    path, strerror(nw == 0 ? EIO : errno));
    585 		syslog(LOG_WARNING,
    586 		    "WARNING: kernel may be incomplete");
    587 		exit(1);
    588         }
    589 
    590         /* Dump symbol table. */
    591 	if (ksymsget(dump_nl[X_SYMTABS].n_value, &symtabs, sizeof(symtabs)))
    592 		return 1;
    593 	stptr = TAILQ_FIRST(&symtabs);
    594 	while (stptr != NULL) {
    595 		if (ksymsget((u_long)stptr, &st, sizeof(st)))
    596 			return 1;
    597 		stptr = TAILQ_NEXT(&st, sd_queue);
    598 		if ((p = malloc(st.sd_symsize)) == NULL)
    599 			return 1;
    600 		if (ksymsget((u_long)st.sd_symstart, p, st.sd_symsize)) {
    601 			free(p);
    602 			return 1;
    603 		}
    604 		nw = fwrite(p, 1, st.sd_symsize, fp);
    605 		free(p);
    606 		if (nw != st.sd_symsize) {
    607 			syslog(LOG_ERR, "%s: %s",
    608 			    path, strerror(nw == 0 ? EIO : errno));
    609 			syslog(LOG_WARNING,
    610 			    "WARNING: kernel may be incomplete");
    611 			exit(1);
    612 		}
    613 	}
    614 
    615 	/* Dump string table. */
    616 	if (ksymsget(dump_nl[X_SYMTABS].n_value, &symtabs, sizeof(symtabs)))
    617 		return 1;
    618 	stptr = TAILQ_FIRST(&symtabs);
    619 	while (stptr != NULL) {
    620 		if (ksymsget((u_long)stptr, &st, sizeof(st)))
    621 			return 1;
    622 		stptr = TAILQ_NEXT(&st, sd_queue);
    623 		if ((p = malloc(st.sd_symsize)) == NULL)
    624 			return 1;
    625 		if (ksymsget((u_long)st.sd_strstart, p, st.sd_strsize)) {
    626 			free(p);
    627 			return 1;
    628 		}
    629 		nw = fwrite(p, 1, st.sd_strsize, fp);
    630 		free(p);
    631 		if (nw != st.sd_strsize) {
    632 			syslog(LOG_ERR, "%s: %s",
    633 			    path, strerror(nw == 0 ? EIO : errno));
    634 			syslog(LOG_WARNING,
    635 			    "WARNING: kernel may be incomplete");
    636 			exit(1);
    637 		}
    638 	}
    639 
    640 	return 0;
    641 }
    642 
    643 static void
    644 save_core(int compress)
    645 {
    646 	FILE *fp;
    647 	int bounds, ifd, nr, nw, ofd, tryksyms;
    648 	char path[MAXPATHLEN], rbuf[MAXPATHLEN];
    649 	const char *rawp;
    650 
    651 	ofd = -1;
    652 	/*
    653 	 * Get the current number and update the bounds file.  Do the update
    654 	 * now, because may fail later and don't want to overwrite anything.
    655 	 */
    656 	umask(066);
    657 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
    658 	if ((fp = fopen(path, "r")) == NULL)
    659 		goto err1;
    660 	if (fgets(buf, sizeof(buf), fp) == NULL) {
    661 		if (ferror(fp))
    662 err1:			syslog(LOG_WARNING, "%s: %m", path);
    663 		bounds = 0;
    664 	} else
    665 		bounds = atoi(buf);
    666 	if (fp != NULL)
    667 		(void)fclose(fp);
    668 	if ((fp = fopen(path, "w")) == NULL)
    669 		syslog(LOG_ERR, "%s: %m", path);
    670 	else {
    671 		(void)fprintf(fp, "%d\n", bounds + 1);
    672 		(void)fclose(fp);
    673 	}
    674 
    675 	/* Create the core file. */
    676 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
    677 	    dirname, bounds, compress ? ".gz" : "");
    678 	if (compress) {
    679 		if ((fp = zopen(path, gzmode)) == NULL) {
    680 			syslog(LOG_ERR, "%s: %m", path);
    681 			exit(1);
    682 		}
    683 	} else {
    684 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    685 		fp  = fdopen(ofd, "w");
    686 		if (fp == NULL) {
    687 			syslog(LOG_ERR, "%s: fdopen: %m", path);
    688 			exit(1);
    689 		}
    690 	}
    691 
    692 	if (dumpcdev == NODEV) {
    693 		/* Open the raw device. */
    694 		rawp = getdiskrawname(rbuf, sizeof(rbuf), ddname);
    695 		if (rawp == NULL) {
    696 			syslog(LOG_WARNING, "%s: %m; can't convert to raw",
    697 			    ddname);
    698 			rawp = ddname;
    699 		}
    700 		if ((ifd = open(rawp, O_RDONLY)) == -1) {
    701 			syslog(LOG_WARNING, "%s: %m; using block device",
    702 			    rawp);
    703 			ifd = dumpfd;
    704 		}
    705 	} else {
    706 		rawp = ddname;
    707 		ifd = dumpfd;
    708 	}
    709 
    710 	/* Seek to the start of the core. */
    711 	Lseek(ifd, dumplo, SEEK_SET);
    712 
    713 	if (kvm_dump_wrtheader(kd_dump, fp, (int32_t)dumpbytes) == -1) {
    714 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
    715 		    kvm_geterr(kd_dump));
    716 		exit(1);
    717 	}
    718 
    719 	/* Copy the core file. */
    720 	syslog(LOG_NOTICE, "writing %score to %s",
    721 	    compress ? "compressed " : "", path);
    722 	for (; dumpbytes > (off_t)0; dumpbytes -= (off_t)nr) {
    723 		char nbuf[7];
    724 		humanize_number(nbuf, 7, dumpbytes, "", HN_AUTOSCALE, 0);
    725 		(void)printf("%7s\r", nbuf);
    726 		(void)fflush(stdout);
    727 		nr = read(ifd, buf, MIN(dumpbytes, (off_t)sizeof(buf)));
    728 		if (nr <= 0) {
    729 			if (nr == 0)
    730 				syslog(LOG_WARNING,
    731 				    "WARNING: EOF on dump device");
    732 			else
    733 				syslog(LOG_ERR, "%s: %m", rawp);
    734 			goto err2;
    735 		}
    736 		nw = fwrite(buf, 1, nr, fp);
    737 		if (nw != nr) {
    738 			syslog(LOG_ERR, "%s: %s",
    739 			    path, strerror(nw == 0 ? EIO : errno));
    740 err2:			syslog(LOG_WARNING,
    741 			    "WARNING: core may be incomplete");
    742 			(void)printf("\n");
    743 			exit(1);
    744 		}
    745 	}
    746 	if (dumpcdev == NODEV)
    747 		(void)close(ifd);
    748 	(void)fclose(fp);
    749 
    750 	/* Create a kernel. */
    751 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
    752 	    dirname, bounds, compress ? ".gz" : "");
    753 	syslog(LOG_NOTICE, "writing %skernel to %s",
    754 	    compress ? "compressed " : "", path);
    755 	for (tryksyms = 1;; tryksyms = 0) {
    756 		if (compress) {
    757 			if ((fp = zopen(path, gzmode)) == NULL) {
    758 				syslog(LOG_ERR, "%s: %m", path);
    759 				exit(1);
    760 			}
    761 		} else {
    762 			ofd = Create(path, S_IRUSR | S_IWUSR);
    763 			fp  = fdopen(ofd, "w");
    764 			if (fp == NULL) {
    765 				syslog(LOG_ERR, "fdopen: %m");
    766 				exit(1);
    767 			}
    768 		}
    769 		if (tryksyms) {
    770 			if (!save_ksyms(fp, path))
    771 				break;
    772 			(void)fclose(fp);
    773 			unlink(path);
    774 		} else {
    775 			save_kernel(fp, path);
    776 			break;
    777 		}
    778 	}
    779 	(void)fclose(fp);
    780 
    781 	/*
    782 	 * For development systems where the crash occurs during boot
    783 	 * to multiuser.
    784 	 */
    785 	sync();
    786 	sleep(1);
    787 	sync();
    788 	sleep(1);
    789 }
    790 
    791 static char *
    792 find_dev(dev_t dev, mode_t type)
    793 {
    794 	DIR *dfd;
    795 	struct dirent *dir;
    796 	struct stat sb;
    797 	char *dp, device[MAXPATHLEN + 1], *p;
    798 	size_t l;
    799 
    800 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
    801 		syslog(LOG_ERR, "%s: %m", _PATH_DEV);
    802 		exit(1);
    803 	}
    804 	strlcpy(device, _PATH_DEV, sizeof(device));
    805 	p = &device[strlen(device)];
    806 	l = sizeof(device) - strlen(device);
    807 	while ((dir = readdir(dfd))) {
    808 		strlcpy(p, dir->d_name, l);
    809 		if (lstat(device, &sb)) {
    810 			syslog(LOG_ERR, "%s: %m", device);
    811 			continue;
    812 		}
    813 		if ((sb.st_mode & S_IFMT) != type)
    814 			continue;
    815 		if (dev == sb.st_rdev) {
    816 			closedir(dfd);
    817 			if ((dp = strdup(device)) == NULL) {
    818 				syslog(LOG_ERR, "%m");
    819 				exit(1);
    820 			}
    821 			return (dp);
    822 		}
    823 	}
    824 	closedir(dfd);
    825 	syslog(LOG_ERR, "can't find device %lld/%lld",
    826 	    (long long)major(dev), (long long)minor(dev));
    827 	exit(1);
    828 }
    829 
    830 static int
    831 get_crashtime(void)
    832 {
    833 	time_t dumptime;			/* Time the dump was taken. */
    834 	struct timeval dtime;
    835 
    836 	if (KREAD(kd_dump, dump_nl[X_TIME_SECOND].n_value, &dumptime) != 0) {
    837 		if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &dtime) != 0) {
    838 			syslog(LOG_WARNING, "kvm_read dumptime: %s (and _time_second "
    839 			    "is not defined also)", kvm_geterr(kd_dump));
    840 			return (0);
    841 		}
    842 		dumptime = dtime.tv_sec;
    843 	}
    844 	if (dumptime == 0) {
    845 		syslog(LOG_WARNING, "dump time is zero");
    846 		return (0);
    847 	}
    848 	syslog(LOG_INFO, "system went down at %s", ctime(&dumptime));
    849 #define	LEEWAY	(60 * SECSPERDAY)
    850 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
    851 		syslog(LOG_WARNING, "dump time is unreasonable");
    852 		return (0);
    853 	}
    854 	return (1);
    855 }
    856 
    857 static int
    858 check_space(void)
    859 {
    860 	FILE *fp;
    861 	off_t minfree, spacefree, kernelsize, needed;
    862 	struct stat st;
    863 	struct statvfs fsbuf;
    864 	char mbuf[100], path[MAXPATHLEN];
    865 
    866 	/* XXX assume a reasonable default, unless we find a kernel. */
    867 	kernelsize = 20 * 1024 * 1024;
    868 	if (!stat(kernel, &st)) kernelsize = st.st_blocks * S_BLKSIZE;
    869 	if (statvfs(dirname, &fsbuf) < 0) {
    870 		syslog(LOG_ERR, "%s: %m", dirname);
    871 		exit(1);
    872 	}
    873 	spacefree = fsbuf.f_bavail;
    874 	spacefree *= fsbuf.f_frsize;
    875 	spacefree /= 1024;
    876 
    877 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
    878 	if ((fp = fopen(path, "r")) == NULL)
    879 		minfree = 0;
    880 	else {
    881 		if (fgets(mbuf, sizeof(mbuf), fp) == NULL)
    882 			minfree = 0;
    883 		else
    884 			minfree = atoi(mbuf);
    885 		(void)fclose(fp);
    886 	}
    887 
    888 	needed = (dumpbytes + kernelsize) / 1024;
    889  	if (minfree > 0 && spacefree - needed < minfree) {
    890 		syslog(LOG_WARNING,
    891 		    "no dump, not enough free space in %s", dirname);
    892 		return (0);
    893 	}
    894 	if (spacefree - needed < minfree)
    895 		syslog(LOG_WARNING,
    896 		    "dump performed, but free space threshold crossed");
    897 	return (1);
    898 }
    899 
    900 static int
    901 Open(const char *name, int rw)
    902 {
    903 	int fd;
    904 
    905 	if ((fd = open(name, rw, 0)) < 0) {
    906 		syslog(LOG_ERR, "%s: %m", name);
    907 		exit(1);
    908 	}
    909 	return (fd);
    910 }
    911 
    912 static void
    913 Lseek(int fd, off_t off, int flag)
    914 {
    915 	off_t ret;
    916 
    917 	ret = lseek(fd, off, flag);
    918 	if (ret == -1) {
    919 		syslog(LOG_ERR, "lseek: %m");
    920 		exit(1);
    921 	}
    922 }
    923 
    924 static int
    925 Create(char *file, int mode)
    926 {
    927 	int fd;
    928 
    929 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
    930 	if (fd < 0) {
    931 		syslog(LOG_ERR, "%s: %m", file);
    932 		exit(1);
    933 	}
    934 	return (fd);
    935 }
    936 
    937 static void
    938 usage(const char *fmt, ...)
    939 {
    940 	va_list ap;
    941 	va_start(ap, fmt);
    942 	(void)vsyslog(LOG_ERR, fmt, ap);
    943 	va_end(ap);
    944 	(void)syslog(LOG_ERR,
    945 	    "Usage: %s [-cfnvz] [-N system] [-Z level] [directory]",
    946 	    getprogname());
    947 	exit(1);
    948 }
    949