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savecore.c revision 1.60
      1 /*	$NetBSD: savecore.c,v 1.60 2003/05/18 02:11:13 itojun 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 1.60 2003/05/18 02:11:13 itojun Exp $");
     47 #endif
     48 #endif /* not lint */
     49 
     50 #include <sys/param.h>
     51 #include <sys/mount.h>
     52 #include <sys/msgbuf.h>
     53 #include <sys/syslog.h>
     54 #include <sys/time.h>
     55 
     56 #include <dirent.h>
     57 #include <errno.h>
     58 #include <fcntl.h>
     59 #include <nlist.h>
     60 #include <paths.h>
     61 #include <stddef.h>
     62 #include <stdio.h>
     63 #include <stdlib.h>
     64 #include <string.h>
     65 #include <time.h>
     66 #include <tzfile.h>
     67 #include <unistd.h>
     68 #include <util.h>
     69 #include <limits.h>
     70 #include <kvm.h>
     71 
     72 extern FILE *zopen(const char *fname, const char *mode);
     73 
     74 #define	KREAD(kd, addr, p)\
     75 	(kvm_read(kd, addr, (char *)(p), sizeof(*(p))) != sizeof(*(p)))
     76 
     77 struct nlist current_nl[] = {	/* Namelist for currently running system. */
     78 #define	X_DUMPDEV	0
     79 	{ "_dumpdev" },
     80 #define	X_DUMPLO	1
     81 	{ "_dumplo" },
     82 #define	X_TIME		2
     83 	{ "_time" },
     84 #define	X_DUMPSIZE	3
     85 	{ "_dumpsize" },
     86 #define	X_VERSION	4
     87 	{ "_version" },
     88 #define	X_DUMPMAG	5
     89 	{ "_dumpmag" },
     90 #define	X_PANICSTR	6
     91 	{ "_panicstr" },
     92 #define	X_PANICSTART	7
     93 	{ "_panicstart" },
     94 #define	X_PANICEND	8
     95 	{ "_panicend" },
     96 #define	X_MSGBUF	9
     97 	{ "_msgbufp" },
     98 	{ NULL },
     99 };
    100 int cursyms[] = { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
    101 int dumpsyms[] = { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
    102 
    103 struct nlist dump_nl[] = {	/* Name list for dumped system. */
    104 	{ "_dumpdev" },		/* Entries MUST be the same as */
    105 	{ "_dumplo" },		/*	those in current_nl[].  */
    106 	{ "_time" },
    107 	{ "_dumpsize" },
    108 	{ "_version" },
    109 	{ "_dumpmag" },
    110 	{ "_panicstr" },
    111 	{ "_panicstart" },
    112 	{ "_panicend" },
    113 	{ "_msgbufp" },
    114 	{ NULL },
    115 };
    116 
    117 /* Types match kernel declarations. */
    118 off_t	dumplo;				/* where dump starts on dumpdev */
    119 u_int32_t dumpmag;			/* magic number in dump */
    120 int	dumpsize;			/* amount of memory dumped */
    121 
    122 const char	*kernel;		/* name of used kernel */
    123 char	*dirname;			/* directory to save dumps in */
    124 char	*ddname;			/* name of dump device */
    125 dev_t	dumpdev;			/* dump device */
    126 int	dumpfd;				/* read/write descriptor on block dev */
    127 kvm_t	*kd_dump;			/* kvm descriptor on block dev	*/
    128 time_t	now;				/* current date */
    129 char	panic_mesg[1024];
    130 long	panicstr;
    131 char	vers[1024];
    132 char	gzmode[3];
    133 
    134 static int	clear, compress, force, verbose;	/* flags */
    135 
    136 void	check_kmem(void);
    137 int	check_space(void);
    138 void	clear_dump(void);
    139 int	Create(char *, int);
    140 int	dump_exists(void);
    141 char	*find_dev(dev_t, int);
    142 int	get_crashtime(void);
    143 void	kmem_setup(void);
    144 void	Lseek(int, off_t, int);
    145 int	main(int, char *[]);
    146 int	Open(const char *, int rw);
    147 char	*rawname(char *s);
    148 void	save_core(void);
    149 void	usage(void);
    150 void	Write(int, void *, int);
    151 
    152 int
    153 main(int argc, char *argv[])
    154 {
    155 	int ch, level;
    156 	char *ep;
    157 
    158 	dirname = NULL;
    159 	kernel = NULL;
    160 	level = 1;		/* default to fastest gzip compression */
    161 	gzmode[0] = 'w';
    162 
    163 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
    164 
    165 	while ((ch = getopt(argc, argv, "cdfN:vzZ:")) != -1)
    166 		switch(ch) {
    167 		case 'c':
    168 			clear = 1;
    169 			break;
    170 		case 'd':		/* Not documented. */
    171 		case 'v':
    172 			verbose = 1;
    173 			break;
    174 		case 'f':
    175 			force = 1;
    176 			break;
    177 		case 'N':
    178 			kernel = optarg;
    179 			break;
    180 		case 'z':
    181 			compress = 1;
    182 			break;
    183 		case 'Z':
    184 			level = (int)strtol(optarg, &ep, 10);
    185 			if (level < 0 || level > 9) {
    186 				(void)syslog(LOG_ERR, "invalid compression %s",
    187 				    optarg);
    188 				usage();
    189 			}
    190 			break;
    191 		case '?':
    192 		default:
    193 			usage();
    194 		}
    195 	argc -= optind;
    196 	argv += optind;
    197 
    198 	if (argc != (clear ? 0 : 1))
    199 		usage();
    200 
    201 	gzmode[1] = level + '0';
    202 	if (!clear)
    203 		dirname = argv[0];
    204 
    205 	if (kernel == NULL) {
    206 		kernel = getbootfile();
    207 	}
    208 
    209 	(void)time(&now);
    210 	kmem_setup();
    211 
    212 	if (clear) {
    213 		clear_dump();
    214 		exit(0);
    215 	}
    216 
    217 	if (!dump_exists() && !force)
    218 		exit(1);
    219 
    220 	check_kmem();
    221 
    222 	if (panicstr)
    223 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
    224 	else
    225 		syslog(LOG_ALERT, "reboot");
    226 
    227 	if ((!get_crashtime() || !check_space()) && !force)
    228 		exit(1);
    229 
    230 	save_core();
    231 
    232 	clear_dump();
    233 	exit(0);
    234 }
    235 
    236 void
    237 kmem_setup(void)
    238 {
    239 	kvm_t *kd_kern;
    240 	char errbuf[_POSIX2_LINE_MAX];
    241 	int i, hdrsz;
    242 
    243 	/*
    244 	 * Some names we need for the currently running system, others for
    245 	 * the system that was running when the dump was made.  The values
    246 	 * obtained from the current system are used to look for things in
    247 	 * /dev/kmem that cannot be found in the kernel namelist, but are
    248 	 * presumed to be the same (since the disk partitions are probably
    249 	 * the same!)
    250 	 */
    251 	kd_kern = kvm_openfiles(kernel, NULL, NULL, O_RDONLY, errbuf);
    252 	if (kd_kern == NULL) {
    253 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    254 		exit(1);
    255 	}
    256 	if (kvm_nlist(kd_kern, current_nl) == -1)
    257 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    258 		    kvm_geterr(kd_kern));
    259 
    260 	for (i = 0; cursyms[i] != -1; i++)
    261 		if (current_nl[cursyms[i]].n_value == 0) {
    262 			syslog(LOG_ERR, "%s: %s not in namelist",
    263 			    kernel, current_nl[cursyms[i]].n_name);
    264 			exit(1);
    265 		}
    266 
    267 	if (KREAD(kd_kern, current_nl[X_DUMPDEV].n_value, &dumpdev) != 0) {
    268 		if (verbose)
    269 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    270 		exit(1);
    271 	}
    272 	if (dumpdev == NODEV) {
    273 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
    274 		exit(1);
    275 	}
    276 	{
    277 	    long l_dumplo;
    278 
    279 	    if (KREAD(kd_kern, current_nl[X_DUMPLO].n_value, &l_dumplo) != 0) {
    280 		    if (verbose)
    281 			syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    282 		    exit(1);
    283 	    }
    284 	    if (l_dumplo == -1) {
    285 		syslog(LOG_WARNING, "no core dump (invalid dumplo)");
    286 		exit(1);
    287 	    }
    288 	    dumplo = DEV_BSIZE * (off_t) l_dumplo;
    289 	}
    290 
    291 	if (verbose)
    292 		(void)printf("dumplo = %lld (%ld * %ld)\n",
    293 		    (long long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
    294 	if (KREAD(kd_kern, current_nl[X_DUMPMAG].n_value, &dumpmag) != 0) {
    295 		if (verbose)
    296 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    297 		exit(1);
    298 	}
    299 
    300 	(void)kvm_read(kd_kern, current_nl[X_VERSION].n_value, vers,
    301 	    sizeof(vers));
    302 	vers[sizeof(vers) - 1] = '\0';
    303 
    304 	ddname = find_dev(dumpdev, S_IFBLK);
    305 	dumpfd = Open(ddname, O_RDWR);
    306 
    307 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
    308 	if (kd_dump == NULL) {
    309 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    310 		exit(1);
    311 	}
    312 
    313 	if (kvm_nlist(kd_dump, dump_nl) == -1)
    314 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    315 		    kvm_geterr(kd_dump));
    316 
    317 	for (i = 0; dumpsyms[i] != -1; i++)
    318 		if (dump_nl[dumpsyms[i]].n_value == 0) {
    319 			syslog(LOG_ERR, "%s: %s not in namelist",
    320 			    kernel, dump_nl[dumpsyms[i]].n_name);
    321 			exit(1);
    322 		}
    323 	hdrsz = kvm_dump_mkheader(kd_dump, dumplo);
    324 
    325 	/*
    326 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
    327 	 * checks, ergo no dump is present...
    328 	 */
    329 	if (hdrsz == 0) {
    330 		syslog(LOG_WARNING, "no core dump");
    331 		exit(1);
    332 	}
    333 	if (hdrsz == -1) {
    334 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
    335 		    kvm_geterr(kd_dump));
    336 		exit(1);
    337 	}
    338 	dumplo += hdrsz;
    339 	kvm_close(kd_kern);
    340 }
    341 
    342 void
    343 check_kmem(void)
    344 {
    345 	char *cp, *bufdata;
    346 	struct kern_msgbuf msgbuf, *bufp;
    347 	long panicloc, panicstart, panicend;
    348 	char core_vers[1024];
    349 
    350 	(void)kvm_read(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
    351 	    sizeof(core_vers));
    352 	core_vers[sizeof(core_vers) - 1] = '\0';
    353 
    354 	if (strcmp(vers, core_vers) != 0)
    355 		syslog(LOG_WARNING,
    356 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
    357 		    kernel, vers, core_vers);
    358 
    359 	panicstart = panicend = 0;
    360 	if (KREAD(kd_dump, dump_nl[X_PANICSTART].n_value, &panicstart) != 0) {
    361 		if (verbose)
    362 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    363 		goto nomsguf;
    364 	}
    365 	if (KREAD(kd_dump, dump_nl[X_PANICEND].n_value, &panicend) != 0) {
    366 		if (verbose)
    367 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    368 		goto nomsguf;
    369 	}
    370 	if (panicstart != 0 && panicend != 0) {
    371 		if (KREAD(kd_dump, dump_nl[X_MSGBUF].n_value, &bufp)) {
    372 			if (verbose)
    373 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    374 			goto nomsguf;
    375 		}
    376 		if (kvm_read(kd_dump, (long)bufp, &msgbuf,
    377 		    offsetof(struct kern_msgbuf, msg_bufc)) !=
    378 		    offsetof(struct kern_msgbuf, msg_bufc)) {
    379 			if (verbose)
    380 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    381 			goto nomsguf;
    382 		}
    383 		if (msgbuf.msg_magic != MSG_MAGIC) {
    384 			if (verbose)
    385 				syslog(LOG_WARNING, "msgbuf magic incorrect");
    386 			goto nomsguf;
    387 		}
    388 		bufdata = malloc(msgbuf.msg_bufs);
    389 		if (bufdata == NULL) {
    390 			if (verbose)
    391 				syslog(LOG_WARNING, "couldn't allocate space for msgbuf data");
    392 			goto nomsguf;
    393 		}
    394 		if (kvm_read(kd_dump, (long)&bufp->msg_bufc, bufdata,
    395 		    msgbuf.msg_bufs) != msgbuf.msg_bufs) {
    396 			if (verbose)
    397 				syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    398 			goto nomsguf;
    399 		}
    400 		cp = panic_mesg;
    401 		while (panicstart != panicend && cp < &panic_mesg[sizeof(panic_mesg)-1]) {
    402 			*cp++ = bufdata[panicstart];
    403 			panicstart++;
    404 			if (panicstart >= msgbuf.msg_bufs)
    405 				panicstart = 0;
    406 		}
    407 		/* Don't end in a new-line */
    408 		cp = &panic_mesg[strlen(panic_mesg)] - 1;
    409 		if (*cp == '\n')
    410 			*cp = '\0';
    411 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
    412 
    413 		panicstr = 1;	/* anything not zero */
    414 		return;
    415 	}
    416 nomsguf:
    417 	if (KREAD(kd_dump, dump_nl[X_PANICSTR].n_value, &panicstr) != 0) {
    418 		if (verbose)
    419 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    420 		return;
    421 	}
    422 	if (panicstr) {
    423 		cp = panic_mesg;
    424 		panicloc = panicstr;
    425 		do {
    426 			if (KREAD(kd_dump, panicloc, cp) != 0) {
    427 				if (verbose)
    428 				    syslog(LOG_WARNING, "kvm_read: %s",
    429 					kvm_geterr(kd_dump));
    430 				break;
    431 			}
    432 			panicloc++;
    433 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
    434 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
    435 	}
    436 }
    437 
    438 int
    439 dump_exists(void)
    440 {
    441 	u_int32_t newdumpmag;
    442 
    443 	if (KREAD(kd_dump, dump_nl[X_DUMPMAG].n_value, &newdumpmag) != 0) {
    444 		if (verbose)
    445 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    446 		return (0);
    447 	}
    448 
    449 	/* Read the dump size. */
    450 	if (KREAD(kd_dump, dump_nl[X_DUMPSIZE].n_value, &dumpsize) != 0) {
    451 		if (verbose)
    452 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    453 		return (0);
    454 	}
    455 	dumpsize *= getpagesize();
    456 
    457 	/*
    458 	 * Return zero if core dump doesn't seem to be there, and note
    459 	 * it for syslog.  This check and return happens after the dump size
    460 	 * is read, so dumpsize is whether or not the core is valid (for -f).
    461 	 */
    462 	if (newdumpmag != dumpmag) {
    463 		if (verbose)
    464 			syslog(LOG_WARNING,
    465 			    "magic number mismatch (0x%x != 0x%x)",
    466 			    newdumpmag, dumpmag);
    467 		syslog(LOG_WARNING, "no core dump");
    468 		return (0);
    469 	}
    470 	return (1);
    471 }
    472 
    473 void
    474 clear_dump(void)
    475 {
    476 	if (kvm_dump_inval(kd_dump) == -1)
    477 		syslog(LOG_ERR, "%s: kvm_clear_dump: %s", ddname,
    478 		    kvm_geterr(kd_dump));
    479 
    480 }
    481 
    482 char buf[1024 * 1024];
    483 
    484 void
    485 save_core(void)
    486 {
    487 	FILE *fp;
    488 	int bounds, ifd, nr, nw, ofd;
    489 	char *rawp, path[MAXPATHLEN];
    490 
    491 	ofd = -1;
    492 	/*
    493 	 * Get the current number and update the bounds file.  Do the update
    494 	 * now, because may fail later and don't want to overwrite anything.
    495 	 */
    496 	umask(066);
    497 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
    498 	if ((fp = fopen(path, "r")) == NULL)
    499 		goto err1;
    500 	if (fgets(buf, sizeof(buf), fp) == NULL) {
    501 		if (ferror(fp))
    502 err1:			syslog(LOG_WARNING, "%s: %m", path);
    503 		bounds = 0;
    504 	} else
    505 		bounds = atoi(buf);
    506 	if (fp != NULL)
    507 		(void)fclose(fp);
    508 	if ((fp = fopen(path, "w")) == NULL)
    509 		syslog(LOG_ERR, "%s: %m", path);
    510 	else {
    511 		(void)fprintf(fp, "%d\n", bounds + 1);
    512 		(void)fclose(fp);
    513 	}
    514 
    515 	/* Create the core file. */
    516 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
    517 	    dirname, bounds, compress ? ".gz" : "");
    518 	if (compress) {
    519 		if ((fp = zopen(path, gzmode)) == NULL) {
    520 			syslog(LOG_ERR, "%s: %m", path);
    521 			exit(1);
    522 		}
    523 	} else {
    524 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    525 		fp  = fdopen(ofd, "w");
    526 		if (fp == NULL) {
    527 			syslog(LOG_ERR, "%s: fdopen: %m", path);
    528 			exit(1);
    529 		}
    530 	}
    531 
    532 	/* Open the raw device. */
    533 	rawp = rawname(ddname);
    534 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
    535 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
    536 		ifd = dumpfd;
    537 	}
    538 
    539 	/* Seek to the start of the core. */
    540 	Lseek(ifd, dumplo, SEEK_SET);
    541 
    542 	if (kvm_dump_wrtheader(kd_dump, fp, dumpsize) == -1) {
    543 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
    544 		    kvm_geterr(kd_dump));
    545 		exit(1);
    546 	}
    547 
    548 	/* Copy the core file. */
    549 	syslog(LOG_NOTICE, "writing %score to %s",
    550 	    compress ? "compressed " : "", path);
    551 	for (; dumpsize > 0; dumpsize -= nr) {
    552 		char nbuf[7];
    553 		humanize_number(nbuf, 7, dumpsize, "", HN_AUTOSCALE, 0);
    554 		(void)printf("%7s\r", nbuf);
    555 		(void)fflush(stdout);
    556 		nr = read(ifd, buf, MIN(dumpsize, sizeof(buf)));
    557 		if (nr <= 0) {
    558 			if (nr == 0)
    559 				syslog(LOG_WARNING,
    560 				    "WARNING: EOF on dump device");
    561 			else
    562 				syslog(LOG_ERR, "%s: %m", rawp);
    563 			goto err2;
    564 		}
    565 		nw = fwrite(buf, 1, nr, fp);
    566 		if (nw != nr) {
    567 			syslog(LOG_ERR, "%s: %s",
    568 			    path, strerror(nw == 0 ? EIO : errno));
    569 err2:			syslog(LOG_WARNING,
    570 			    "WARNING: core may be incomplete");
    571 			(void)printf("\n");
    572 			exit(1);
    573 		}
    574 	}
    575 	(void)close(ifd);
    576 	(void)fclose(fp);
    577 
    578 	/* Copy the kernel. */
    579 	ifd = Open(kernel, O_RDONLY);
    580 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
    581 	    dirname, bounds, compress ? ".gz" : "");
    582 	if (compress) {
    583 		if ((fp = zopen(path, gzmode)) == NULL) {
    584 			syslog(LOG_ERR, "%s: %m", path);
    585 			exit(1);
    586 		}
    587 	} else
    588 		ofd = Create(path, S_IRUSR | S_IWUSR);
    589 	syslog(LOG_NOTICE, "writing %skernel to %s",
    590 	    compress ? "compressed " : "", path);
    591 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
    592 		if (compress)
    593 			nw = fwrite(buf, 1, nr, fp);
    594 		else
    595 			nw = write(ofd, buf, nr);
    596 		if (nw != nr) {
    597 			syslog(LOG_ERR, "%s: %s",
    598 			    path, strerror(nw == 0 ? EIO : errno));
    599 			syslog(LOG_WARNING,
    600 			    "WARNING: kernel may be incomplete");
    601 			exit(1);
    602 		}
    603 	}
    604 	if (nr < 0) {
    605 		syslog(LOG_ERR, "%s: %m", kernel);
    606 		syslog(LOG_WARNING, "WARNING: kernel may be incomplete");
    607 		exit(1);
    608 	}
    609 	if (compress)
    610 		(void)fclose(fp);
    611 	else
    612 		(void)close(ofd);
    613 }
    614 
    615 char *
    616 find_dev(dev_t dev, int type)
    617 {
    618 	DIR *dfd;
    619 	struct dirent *dir;
    620 	struct stat sb;
    621 	char *dp, device[MAXPATHLEN + 1], *p;
    622 	size_t l;
    623 
    624 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
    625 		syslog(LOG_ERR, "%s: %m", _PATH_DEV);
    626 		exit(1);
    627 	}
    628 	strlcpy(device, _PATH_DEV, sizeof(device));
    629 	p = &device[strlen(device)];
    630 	l = sizeof(device) - strlen(device);
    631 	while ((dir = readdir(dfd))) {
    632 		strlcpy(p, dir->d_name, l);
    633 		if (lstat(device, &sb)) {
    634 			syslog(LOG_ERR, "%s: %m", device);
    635 			continue;
    636 		}
    637 		if ((sb.st_mode & S_IFMT) != type)
    638 			continue;
    639 		if (dev == sb.st_rdev) {
    640 			closedir(dfd);
    641 			if ((dp = strdup(device)) == NULL) {
    642 				syslog(LOG_ERR, "%m");
    643 				exit(1);
    644 			}
    645 			return (dp);
    646 		}
    647 	}
    648 	closedir(dfd);
    649 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
    650 	exit(1);
    651 }
    652 
    653 char *
    654 rawname(char *s)
    655 {
    656 	char *sl;
    657 	char name[MAXPATHLEN];
    658 
    659 	if ((sl = strrchr(s, '/')) == NULL || sl[1] == '0') {
    660 		syslog(LOG_ERR,
    661 		    "can't make raw dump device name from %s", s);
    662 		return (s);
    663 	}
    664 	(void)snprintf(name, sizeof(name), "%.*s/r%s", (int)(sl - s), s,
    665 	    sl + 1);
    666 	if ((sl = strdup(name)) == NULL) {
    667 		syslog(LOG_ERR, "%m");
    668 		exit(1);
    669 	}
    670 	return (sl);
    671 }
    672 
    673 int
    674 get_crashtime(void)
    675 {
    676 	struct timeval dtime;
    677 	time_t dumptime;			/* Time the dump was taken. */
    678 
    679 	if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &dtime) != 0) {
    680 		if (verbose)
    681 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    682 		return (0);
    683 	}
    684 	dumptime = dtime.tv_sec;
    685 	if (dumptime == 0) {
    686 		if (verbose)
    687 			syslog(LOG_ERR, "dump time is zero");
    688 		return (0);
    689 	}
    690 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
    691 #define	LEEWAY	(7 * SECSPERDAY)
    692 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
    693 		(void)printf("dump time is unreasonable\n");
    694 		return (0);
    695 	}
    696 	return (1);
    697 }
    698 
    699 int
    700 check_space(void)
    701 {
    702 	FILE *fp;
    703 	off_t minfree, spacefree, kernelsize, needed;
    704 	struct stat st;
    705 	struct statfs fsbuf;
    706 	char mbuf[100], path[MAXPATHLEN];
    707 
    708 #ifdef __GNUC__
    709 	(void) &minfree;
    710 #endif
    711 
    712 	if (stat(kernel, &st) < 0) {
    713 		syslog(LOG_ERR, "%s: %m", kernel);
    714 		exit(1);
    715 	}
    716 	kernelsize = st.st_blocks * S_BLKSIZE;
    717 	if (statfs(dirname, &fsbuf) < 0) {
    718 		syslog(LOG_ERR, "%s: %m", dirname);
    719 		exit(1);
    720 	}
    721 	spacefree = fsbuf.f_bavail;
    722 	spacefree *= fsbuf.f_bsize;
    723 	spacefree /= 1024;
    724 
    725 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
    726 	if ((fp = fopen(path, "r")) == NULL)
    727 		minfree = 0;
    728 	else {
    729 		if (fgets(mbuf, sizeof(mbuf), fp) == NULL)
    730 			minfree = 0;
    731 		else
    732 			minfree = atoi(mbuf);
    733 		(void)fclose(fp);
    734 	}
    735 
    736 	needed = (dumpsize + kernelsize) / 1024;
    737  	if (minfree > 0 && spacefree - needed < minfree) {
    738 		syslog(LOG_WARNING,
    739 		    "no dump, not enough free space in %s", dirname);
    740 		return (0);
    741 	}
    742 	if (spacefree - needed < minfree)
    743 		syslog(LOG_WARNING,
    744 		    "dump performed, but free space threshold crossed");
    745 	return (1);
    746 }
    747 
    748 int
    749 Open(const char *name, int rw)
    750 {
    751 	int fd;
    752 
    753 	if ((fd = open(name, rw, 0)) < 0) {
    754 		syslog(LOG_ERR, "%s: %m", name);
    755 		exit(1);
    756 	}
    757 	return (fd);
    758 }
    759 
    760 void
    761 Lseek(int fd, off_t off, int flag)
    762 {
    763 	off_t ret;
    764 
    765 	ret = lseek(fd, off, flag);
    766 	if (ret == -1) {
    767 		syslog(LOG_ERR, "lseek: %m");
    768 		exit(1);
    769 	}
    770 }
    771 
    772 int
    773 Create(char *file, int mode)
    774 {
    775 	int fd;
    776 
    777 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
    778 	if (fd < 0) {
    779 		syslog(LOG_ERR, "%s: %m", file);
    780 		exit(1);
    781 	}
    782 	return (fd);
    783 }
    784 
    785 void
    786 Write(int fd, void *bp, int size)
    787 {
    788 	int n;
    789 
    790 	if ((n = write(fd, bp, size)) < size) {
    791 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
    792 		exit(1);
    793 	}
    794 }
    795 
    796 void
    797 usage(void)
    798 {
    799 	(void)syslog(LOG_ERR,
    800 	    "usage: savecore [-cfvz] [-N system] [-Z level] directory");
    801 	exit(1);
    802 }
    803