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savecore.c revision 1.56
      1 /*	$NetBSD: savecore.c,v 1.56 2002/03/06 13:13:08 tsutsui 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 1.56 2002/03/06 13:13:08 tsutsui 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 long	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 	if (KREAD(kd_kern, current_nl[X_DUMPLO].n_value, &dumplo) != 0) {
    278 		if (verbose)
    279 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    280 		exit(1);
    281 	}
    282 	if (dumplo == -1) {
    283 	    syslog(LOG_WARNING, "no core dump (invalid dumplo)");
    284 	    exit(1);
    285 	}
    286 	dumplo *= DEV_BSIZE;
    287 	if (verbose)
    288 		(void)printf("dumplo = %ld (%ld * %ld)\n",
    289 		    (long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
    290 	if (KREAD(kd_kern, current_nl[X_DUMPMAG].n_value, &dumpmag) != 0) {
    291 		if (verbose)
    292 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    293 		exit(1);
    294 	}
    295 
    296 	(void)kvm_read(kd_kern, current_nl[X_VERSION].n_value, vers,
    297 	    sizeof(vers));
    298 	vers[sizeof(vers) - 1] = '\0';
    299 
    300 	ddname = find_dev(dumpdev, S_IFBLK);
    301 	dumpfd = Open(ddname, O_RDWR);
    302 
    303 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
    304 	if (kd_dump == NULL) {
    305 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    306 		exit(1);
    307 	}
    308 
    309 	if (kvm_nlist(kd_dump, dump_nl) == -1)
    310 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    311 		    kvm_geterr(kd_dump));
    312 
    313 	for (i = 0; dumpsyms[i] != -1; i++)
    314 		if (dump_nl[dumpsyms[i]].n_value == 0) {
    315 			syslog(LOG_ERR, "%s: %s not in namelist",
    316 			    kernel, dump_nl[dumpsyms[i]].n_name);
    317 			exit(1);
    318 		}
    319 	hdrsz = kvm_dump_mkheader(kd_dump, (off_t)dumplo);
    320 
    321 	/*
    322 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
    323 	 * checks, ergo no dump is present...
    324 	 */
    325 	if (hdrsz == 0) {
    326 		syslog(LOG_WARNING, "no core dump");
    327 		exit(1);
    328 	}
    329 	if (hdrsz == -1) {
    330 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
    331 		    kvm_geterr(kd_dump));
    332 		exit(1);
    333 	}
    334 	dumplo += hdrsz;
    335 	kvm_close(kd_kern);
    336 }
    337 
    338 void
    339 check_kmem(void)
    340 {
    341 	char *cp, *bufdata;
    342 	struct kern_msgbuf msgbuf, *bufp;
    343 	long panicloc, panicstart, panicend;
    344 	char core_vers[1024];
    345 
    346 	(void)kvm_read(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
    347 	    sizeof(core_vers));
    348 	core_vers[sizeof(core_vers) - 1] = '\0';
    349 
    350 	if (strcmp(vers, core_vers) != 0)
    351 		syslog(LOG_WARNING,
    352 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
    353 		    kernel, vers, core_vers);
    354 
    355 	panicstart = panicend = 0;
    356 	if (KREAD(kd_dump, dump_nl[X_PANICSTART].n_value, &panicstart) != 0) {
    357 		if (verbose)
    358 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    359 		goto nomsguf;
    360 	}
    361 	if (KREAD(kd_dump, dump_nl[X_PANICEND].n_value, &panicend) != 0) {
    362 		if (verbose)
    363 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    364 		goto nomsguf;
    365 	}
    366 	if (panicstart != 0 && panicend != 0) {
    367 		if (KREAD(kd_dump, dump_nl[X_MSGBUF].n_value, &bufp)) {
    368 			if (verbose)
    369 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    370 			goto nomsguf;
    371 		}
    372 		if (kvm_read(kd_dump, (long)bufp, &msgbuf,
    373 		    offsetof(struct kern_msgbuf, msg_bufc)) !=
    374 		    offsetof(struct kern_msgbuf, msg_bufc)) {
    375 			if (verbose)
    376 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    377 			goto nomsguf;
    378 		}
    379 		if (msgbuf.msg_magic != MSG_MAGIC) {
    380 			if (verbose)
    381 				syslog(LOG_WARNING, "msgbuf magic incorrect");
    382 			goto nomsguf;
    383 		}
    384 		bufdata = malloc(msgbuf.msg_bufs);
    385 		if (bufdata == NULL) {
    386 			if (verbose)
    387 				syslog(LOG_WARNING, "couldn't allocate space for msgbuf data");
    388 			goto nomsguf;
    389 		}
    390 		if (kvm_read(kd_dump, (long)&bufp->msg_bufc, bufdata,
    391 		    msgbuf.msg_bufs) != msgbuf.msg_bufs) {
    392 			if (verbose)
    393 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    394 			goto nomsguf;
    395 		}
    396 		cp = panic_mesg;
    397 		while (panicstart != panicend && cp < &panic_mesg[sizeof(panic_mesg)-1]) {
    398 			*cp++ = bufdata[panicstart];
    399 			panicstart++;
    400 			if (panicstart >= msgbuf.msg_bufs)
    401 				panicstart = 0;
    402 		}
    403 		/* Don't end in a new-line */
    404 		cp = &panic_mesg[strlen(panic_mesg)] - 1;
    405 		if (*cp == '\n')
    406 			*cp = '\0';
    407 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
    408 
    409 		panicstr = 1;	/* anything not zero */
    410 		return;
    411 	}
    412 nomsguf:
    413 	if (KREAD(kd_dump, dump_nl[X_PANICSTR].n_value, &panicstr) != 0) {
    414 		if (verbose)
    415 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    416 		return;
    417 	}
    418 	if (panicstr) {
    419 		cp = panic_mesg;
    420 		panicloc = panicstr;
    421 		do {
    422 			if (KREAD(kd_dump, panicloc, cp) != 0) {
    423 				if (verbose)
    424 				    syslog(LOG_WARNING, "kvm_read: %s",
    425 					kvm_geterr(kd_dump));
    426 				break;
    427 			}
    428 			panicloc++;
    429 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
    430 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
    431 	}
    432 }
    433 
    434 int
    435 dump_exists(void)
    436 {
    437 	u_int32_t newdumpmag;
    438 
    439 	if (KREAD(kd_dump, dump_nl[X_DUMPMAG].n_value, &newdumpmag) != 0) {
    440 		if (verbose)
    441 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    442 		return (0);
    443 	}
    444 
    445 	/* Read the dump size. */
    446 	if (KREAD(kd_dump, dump_nl[X_DUMPSIZE].n_value, &dumpsize) != 0) {
    447 		if (verbose)
    448 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    449 		return (0);
    450 	}
    451 	dumpsize *= getpagesize();
    452 
    453 	/*
    454 	 * Return zero if core dump doesn't seem to be there, and note
    455 	 * it for syslog.  This check and return happens after the dump size
    456 	 * is read, so dumpsize is whether or not the core is valid (for -f).
    457 	 */
    458 	if (newdumpmag != dumpmag) {
    459 		if (verbose)
    460 			syslog(LOG_WARNING,
    461 			    "magic number mismatch (0x%x != 0x%x)",
    462 			    newdumpmag, dumpmag);
    463 		syslog(LOG_WARNING, "no core dump");
    464 		return (0);
    465 	}
    466 	return (1);
    467 }
    468 
    469 void
    470 clear_dump(void)
    471 {
    472 	if (kvm_dump_inval(kd_dump) == -1)
    473 		syslog(LOG_ERR, "%s: kvm_clear_dump: %s", ddname,
    474 		    kvm_geterr(kd_dump));
    475 
    476 }
    477 
    478 char buf[1024 * 1024];
    479 
    480 void
    481 save_core(void)
    482 {
    483 	FILE *fp;
    484 	int bounds, ifd, nr, nw, ofd;
    485 	char *rawp, path[MAXPATHLEN];
    486 
    487 	ofd = -1;
    488 	/*
    489 	 * Get the current number and update the bounds file.  Do the update
    490 	 * now, because may fail later and don't want to overwrite anything.
    491 	 */
    492 	umask(066);
    493 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
    494 	if ((fp = fopen(path, "r")) == NULL)
    495 		goto err1;
    496 	if (fgets(buf, sizeof(buf), fp) == NULL) {
    497 		if (ferror(fp))
    498 err1:			syslog(LOG_WARNING, "%s: %m", path);
    499 		bounds = 0;
    500 	} else
    501 		bounds = atoi(buf);
    502 	if (fp != NULL)
    503 		(void)fclose(fp);
    504 	if ((fp = fopen(path, "w")) == NULL)
    505 		syslog(LOG_ERR, "%s: %m", path);
    506 	else {
    507 		(void)fprintf(fp, "%d\n", bounds + 1);
    508 		(void)fclose(fp);
    509 	}
    510 
    511 	/* Create the core file. */
    512 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
    513 	    dirname, bounds, compress ? ".gz" : "");
    514 	if (compress) {
    515 		if ((fp = zopen(path, gzmode)) == NULL) {
    516 			syslog(LOG_ERR, "%s: %m", path);
    517 			exit(1);
    518 		}
    519 	} else {
    520 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    521 		fp  = fdopen(ofd, "w");
    522 		if (fp == NULL) {
    523 			syslog(LOG_ERR, "%s: fdopen: %m", path);
    524 			exit(1);
    525 		}
    526 	}
    527 
    528 	/* Open the raw device. */
    529 	rawp = rawname(ddname);
    530 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
    531 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
    532 		ifd = dumpfd;
    533 	}
    534 
    535 	/* Seek to the start of the core. */
    536 	Lseek(ifd, (off_t)dumplo, SEEK_SET);
    537 
    538 	if (kvm_dump_wrtheader(kd_dump, fp, dumpsize) == -1) {
    539 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
    540 		    kvm_geterr(kd_dump));
    541 		exit(1);
    542 	}
    543 
    544 	/* Copy the core file. */
    545 	syslog(LOG_NOTICE, "writing %score to %s",
    546 	    compress ? "compressed " : "", path);
    547 	for (; dumpsize > 0; dumpsize -= nr) {
    548 		(void)printf("%8dK\r", dumpsize / 1024);
    549 		(void)fflush(stdout);
    550 		nr = read(ifd, buf, MIN(dumpsize, sizeof(buf)));
    551 		if (nr <= 0) {
    552 			if (nr == 0)
    553 				syslog(LOG_WARNING,
    554 				    "WARNING: EOF on dump device");
    555 			else
    556 				syslog(LOG_ERR, "%s: %m", rawp);
    557 			goto err2;
    558 		}
    559 		nw = fwrite(buf, 1, nr, fp);
    560 		if (nw != nr) {
    561 			syslog(LOG_ERR, "%s: %s",
    562 			    path, strerror(nw == 0 ? EIO : errno));
    563 err2:			syslog(LOG_WARNING,
    564 			    "WARNING: core may be incomplete");
    565 			(void)printf("\n");
    566 			exit(1);
    567 		}
    568 	}
    569 	(void)close(ifd);
    570 	(void)fclose(fp);
    571 
    572 	/* Copy the kernel. */
    573 	ifd = Open(kernel, O_RDONLY);
    574 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
    575 	    dirname, bounds, compress ? ".gz" : "");
    576 	if (compress) {
    577 		if ((fp = zopen(path, gzmode)) == NULL) {
    578 			syslog(LOG_ERR, "%s: %m", path);
    579 			exit(1);
    580 		}
    581 	} else
    582 		ofd = Create(path, S_IRUSR | S_IWUSR);
    583 	syslog(LOG_NOTICE, "writing %skernel to %s",
    584 	    compress ? "compressed " : "", path);
    585 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
    586 		if (compress)
    587 			nw = fwrite(buf, 1, nr, fp);
    588 		else
    589 			nw = write(ofd, buf, nr);
    590 		if (nw != nr) {
    591 			syslog(LOG_ERR, "%s: %s",
    592 			    path, strerror(nw == 0 ? EIO : errno));
    593 			syslog(LOG_WARNING,
    594 			    "WARNING: kernel may be incomplete");
    595 			exit(1);
    596 		}
    597 	}
    598 	if (nr < 0) {
    599 		syslog(LOG_ERR, "%s: %m", kernel);
    600 		syslog(LOG_WARNING, "WARNING: kernel may be incomplete");
    601 		exit(1);
    602 	}
    603 	if (compress)
    604 		(void)fclose(fp);
    605 	else
    606 		(void)close(ofd);
    607 }
    608 
    609 char *
    610 find_dev(dev_t dev, int type)
    611 {
    612 	DIR *dfd;
    613 	struct dirent *dir;
    614 	struct stat sb;
    615 	char *dp, device[MAXPATHLEN + 1];
    616 
    617 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
    618 		syslog(LOG_ERR, "%s: %m", _PATH_DEV);
    619 		exit(1);
    620 	}
    621 	(void)strcpy(device, _PATH_DEV);
    622 	while ((dir = readdir(dfd))) {
    623 		(void)strcpy(device + sizeof(_PATH_DEV) - 1, dir->d_name);
    624 		if (lstat(device, &sb)) {
    625 			syslog(LOG_ERR, "%s: %m", device);
    626 			continue;
    627 		}
    628 		if ((sb.st_mode & S_IFMT) != type)
    629 			continue;
    630 		if (dev == sb.st_rdev) {
    631 			closedir(dfd);
    632 			if ((dp = strdup(device)) == NULL) {
    633 				syslog(LOG_ERR, "%m");
    634 				exit(1);
    635 			}
    636 			return (dp);
    637 		}
    638 	}
    639 	closedir(dfd);
    640 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
    641 	exit(1);
    642 }
    643 
    644 char *
    645 rawname(char *s)
    646 {
    647 	char *sl;
    648 	char name[MAXPATHLEN];
    649 
    650 	if ((sl = strrchr(s, '/')) == NULL || sl[1] == '0') {
    651 		syslog(LOG_ERR,
    652 		    "can't make raw dump device name from %s", s);
    653 		return (s);
    654 	}
    655 	(void)snprintf(name, sizeof(name), "%.*s/r%s", (int)(sl - s), s,
    656 	    sl + 1);
    657 	if ((sl = strdup(name)) == NULL) {
    658 		syslog(LOG_ERR, "%m");
    659 		exit(1);
    660 	}
    661 	return (sl);
    662 }
    663 
    664 int
    665 get_crashtime(void)
    666 {
    667 	struct timeval dtime;
    668 	time_t dumptime;			/* Time the dump was taken. */
    669 
    670 	if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &dtime) != 0) {
    671 		if (verbose)
    672 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    673 		return (0);
    674 	}
    675 	dumptime = dtime.tv_sec;
    676 	if (dumptime == 0) {
    677 		if (verbose)
    678 			syslog(LOG_ERR, "dump time is zero");
    679 		return (0);
    680 	}
    681 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
    682 #define	LEEWAY	(7 * SECSPERDAY)
    683 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
    684 		(void)printf("dump time is unreasonable\n");
    685 		return (0);
    686 	}
    687 	return (1);
    688 }
    689 
    690 int
    691 check_space(void)
    692 {
    693 	FILE *fp;
    694 	off_t minfree, spacefree, kernelsize, needed;
    695 	struct stat st;
    696 	struct statfs fsbuf;
    697 	char mbuf[100], path[MAXPATHLEN];
    698 
    699 #ifdef __GNUC__
    700 	(void) &minfree;
    701 #endif
    702 
    703 	if (stat(kernel, &st) < 0) {
    704 		syslog(LOG_ERR, "%s: %m", kernel);
    705 		exit(1);
    706 	}
    707 	kernelsize = st.st_blocks * S_BLKSIZE;
    708 	if (statfs(dirname, &fsbuf) < 0) {
    709 		syslog(LOG_ERR, "%s: %m", dirname);
    710 		exit(1);
    711 	}
    712 	spacefree = fsbuf.f_bavail;
    713 	spacefree *= fsbuf.f_bsize;
    714 	spacefree /= 1024;
    715 
    716 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
    717 	if ((fp = fopen(path, "r")) == NULL)
    718 		minfree = 0;
    719 	else {
    720 		if (fgets(mbuf, sizeof(mbuf), fp) == NULL)
    721 			minfree = 0;
    722 		else
    723 			minfree = atoi(mbuf);
    724 		(void)fclose(fp);
    725 	}
    726 
    727 	needed = (dumpsize + kernelsize) / 1024;
    728  	if (minfree > 0 && spacefree - needed < minfree) {
    729 		syslog(LOG_WARNING,
    730 		    "no dump, not enough free space in %s", dirname);
    731 		return (0);
    732 	}
    733 	if (spacefree - needed < minfree)
    734 		syslog(LOG_WARNING,
    735 		    "dump performed, but free space threshold crossed");
    736 	return (1);
    737 }
    738 
    739 int
    740 Open(const char *name, int rw)
    741 {
    742 	int fd;
    743 
    744 	if ((fd = open(name, rw, 0)) < 0) {
    745 		syslog(LOG_ERR, "%s: %m", name);
    746 		exit(1);
    747 	}
    748 	return (fd);
    749 }
    750 
    751 void
    752 Lseek(int fd, off_t off, int flag)
    753 {
    754 	off_t ret;
    755 
    756 	ret = lseek(fd, off, flag);
    757 	if (ret == -1) {
    758 		syslog(LOG_ERR, "lseek: %m");
    759 		exit(1);
    760 	}
    761 }
    762 
    763 int
    764 Create(char *file, int mode)
    765 {
    766 	int fd;
    767 
    768 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
    769 	if (fd < 0) {
    770 		syslog(LOG_ERR, "%s: %m", file);
    771 		exit(1);
    772 	}
    773 	return (fd);
    774 }
    775 
    776 void
    777 Write(int fd, void *bp, int size)
    778 {
    779 	int n;
    780 
    781 	if ((n = write(fd, bp, size)) < size) {
    782 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
    783 		exit(1);
    784 	}
    785 }
    786 
    787 void
    788 usage(void)
    789 {
    790 	(void)syslog(LOG_ERR,
    791 	    "usage: savecore [-cfvz] [-N system] [-Z level] directory");
    792 	exit(1);
    793 }
    794