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savecore.c revision 1.44
      1 /*	$NetBSD: savecore.c,v 1.44 2000/12/07 03:17:17 wiz 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 1.44 2000/12/07 03:17:17 wiz Exp $");
     47 #endif
     48 #endif /* not lint */
     49 
     50 #include <sys/param.h>
     51 #include <sys/stat.h>
     52 #include <sys/mount.h>
     53 #include <sys/syslog.h>
     54 #include <sys/time.h>
     55 #include <sys/sysctl.h>
     56 #include <machine/cpu.h>
     57 
     58 #include <dirent.h>
     59 #include <errno.h>
     60 #include <fcntl.h>
     61 #include <nlist.h>
     62 #include <paths.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 <limits.h>
     70 #include <kvm.h>
     71 
     72 extern FILE *zopen __P((const char *fname, const char *mode, int bits));
     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_PANICSTR	5
     89 	{ "_panicstr" },
     90 #define	X_DUMPMAG	6
     91 	{ "_dumpmag" },
     92 	{ NULL },
     93 };
     94 int cursyms[] = { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
     95 int dumpsyms[] = { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
     96 
     97 struct nlist dump_nl[] = {	/* Name list for dumped system. */
     98 	{ "_dumpdev" },		/* Entries MUST be the same as */
     99 	{ "_dumplo" },		/*	those in current_nl[].  */
    100 	{ "_time" },
    101 	{ "_dumpsize" },
    102 	{ "_version" },
    103 	{ "_panicstr" },
    104 	{ "_dumpmag" },
    105 	{ NULL },
    106 };
    107 
    108 /* Types match kernel declarations. */
    109 long	dumplo;				/* where dump starts on dumpdev */
    110 int	dumpmag;			/* magic number in dump */
    111 int	dumpsize;			/* amount of memory dumped */
    112 
    113 char	*kernel;			/* name of used kernel */
    114 char	*dirname;			/* directory to save dumps in */
    115 char	*ddname;			/* name of dump device */
    116 dev_t	dumpdev;			/* dump device */
    117 int	dumpfd;				/* read/write descriptor on block dev */
    118 kvm_t	*kd_dump;			/* kvm descriptor on block dev	*/
    119 time_t	now;				/* current date */
    120 char	panic_mesg[1024];
    121 long	panicstr;
    122 char	vers[1024];
    123 
    124 int	clear, compress, force, verbose;	/* flags */
    125 
    126 void	 check_kmem __P((void));
    127 int	 check_space __P((void));
    128 void	 clear_dump __P((void));
    129 int	 Create __P((char *, int));
    130 int	 dump_exists __P((void));
    131 char	*find_dev __P((dev_t, int));
    132 int	 get_crashtime __P((void));
    133 void	 kmem_setup __P((void));
    134 void	 log __P((int, char *, ...));
    135 void	 Lseek __P((int, off_t, int));
    136 int	 main __P((int, char *[]));
    137 int	 Open __P((char *, int rw));
    138 char	*rawname __P((char *s));
    139 void	 save_core __P((void));
    140 void	 usage __P((void));
    141 void	 Write __P((int, void *, int));
    142 
    143 int
    144 main(argc, argv)
    145 	int argc;
    146 	char *argv[];
    147 {
    148 	int ch;
    149 #ifdef CPU_BOOTED_KERNEL
    150 	int mib[2];
    151 	size_t size;
    152 	char buf[MAXPATHLEN];
    153 #endif
    154 
    155 	dirname = NULL;
    156 	kernel = NULL;
    157 
    158 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
    159 
    160 	while ((ch = getopt(argc, argv, "cdfN:vz")) != -1)
    161 		switch(ch) {
    162 		case 'c':
    163 			clear = 1;
    164 			break;
    165 		case 'd':		/* Not documented. */
    166 		case 'v':
    167 			verbose = 1;
    168 			break;
    169 		case 'f':
    170 			force = 1;
    171 			break;
    172 		case 'N':
    173 			kernel = optarg;
    174 			break;
    175 		case 'z':
    176 			compress = 1;
    177 			break;
    178 		case '?':
    179 		default:
    180 			usage();
    181 		}
    182 	argc -= optind;
    183 	argv += optind;
    184 
    185 	if (argc != (clear ? 0 : 1))
    186 		usage();
    187 
    188 	if (!clear)
    189 		dirname = argv[0];
    190 
    191 	if (kernel == NULL) {
    192 		kernel = _PATH_UNIX;
    193 #ifdef CPU_BOOTED_KERNEL
    194 		/* find real boot-kernel name */
    195 		mib[0] = CTL_MACHDEP;
    196 		mib[1] = CPU_BOOTED_KERNEL;
    197 		size = sizeof(buf) - 1;
    198 		if (sysctl(mib, 2, buf + 1, &size, NULL, NULL) == 0) {
    199 			/*
    200 			 * traditionally, this sysctl returns the
    201 			 * relative path of the kernel with the
    202 			 * leading slash stripped -- could be empty,
    203 			 * though (e.g. when netbooting).
    204 			 */
    205 			if (buf[1] != '\0') {
    206 				buf[0] = '/';
    207 				kernel = buf;
    208 			}
    209 		}
    210 #endif
    211 	}
    212 
    213 	(void)time(&now);
    214 	kmem_setup();
    215 
    216 	if (clear) {
    217 		clear_dump();
    218 		exit(0);
    219 	}
    220 
    221 	if (!dump_exists() && !force)
    222 		exit(1);
    223 
    224 	check_kmem();
    225 
    226 	if (panicstr)
    227 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
    228 	else
    229 		syslog(LOG_ALERT, "reboot");
    230 
    231 	if ((!get_crashtime() || !check_space()) && !force)
    232 		exit(1);
    233 
    234 	save_core();
    235 
    236 	clear_dump();
    237 	exit(0);
    238 }
    239 
    240 void
    241 kmem_setup()
    242 {
    243 	kvm_t	*kd_kern;
    244 	char	errbuf[_POSIX2_LINE_MAX];
    245 	int	i, hdrsz;
    246 
    247 	/*
    248 	 * Some names we need for the currently running system, others for
    249 	 * the system that was running when the dump was made.  The values
    250 	 * obtained from the current system are used to look for things in
    251 	 * /dev/kmem that cannot be found in the kernel namelist, but are
    252 	 * presumed to be the same (since the disk partitions are probably
    253 	 * the same!)
    254 	 */
    255 	kd_kern = kvm_openfiles(kernel, NULL, NULL, O_RDONLY, errbuf);
    256 	if (kd_kern == NULL) {
    257 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    258 		exit(1);
    259 	}
    260 	if (kvm_nlist(kd_kern, current_nl) == -1)
    261 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    262 			kvm_geterr(kd_kern));
    263 
    264 	for (i = 0; cursyms[i] != -1; i++)
    265 		if (current_nl[cursyms[i]].n_value == 0) {
    266 			syslog(LOG_ERR, "%s: %s not in namelist",
    267 			    kernel, current_nl[cursyms[i]].n_name);
    268 			exit(1);
    269 		}
    270 
    271 	if (KREAD(kd_kern, current_nl[X_DUMPDEV].n_value, &dumpdev) != 0) {
    272 		if (verbose)
    273 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    274 		exit(1);
    275 	}
    276 	if (dumpdev == NODEV) {
    277 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
    278 		exit(1);
    279 	}
    280 	if (KREAD(kd_kern, current_nl[X_DUMPLO].n_value, &dumplo) != 0) {
    281 		if (verbose)
    282 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    283 		exit(1);
    284 	}
    285 	dumplo *= DEV_BSIZE;
    286 	if (verbose)
    287 		(void)printf("dumplo = %ld (%ld * %ld)\n",
    288 		    (long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
    289 	if (KREAD(kd_kern, current_nl[X_DUMPMAG].n_value, &dumpmag) != 0) {
    290 		if (verbose)
    291 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    292 		exit(1);
    293 	}
    294 
    295 	(void)kvm_read(kd_kern, current_nl[X_VERSION].n_value,
    296 	    vers, sizeof(vers));
    297 	vers[sizeof(vers) - 1] = '\0';
    298 
    299 	ddname = find_dev(dumpdev, S_IFBLK);
    300 	dumpfd = Open(ddname, O_RDWR);
    301 
    302 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
    303 	if (kd_dump == NULL) {
    304 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    305 		exit(1);
    306 	}
    307 
    308 	if (kvm_nlist(kd_dump, dump_nl) == -1)
    309 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    310 		    kvm_geterr(kd_dump));
    311 
    312 	for (i = 0; dumpsyms[i] != -1; i++)
    313 		if (dump_nl[dumpsyms[i]].n_value == 0) {
    314 			syslog(LOG_ERR, "%s: %s not in namelist",
    315 			    kernel, dump_nl[dumpsyms[i]].n_name);
    316 			exit(1);
    317 		}
    318 	hdrsz = kvm_dump_mkheader(kd_dump, (off_t)dumplo);
    319 
    320 	/*
    321 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
    322 	 * checks, ergo no dump is present...
    323 	 */
    324 	if (hdrsz == 0) {
    325 		syslog(LOG_WARNING, "no core dump");
    326 		exit(1);
    327 	}
    328 	if (hdrsz == -1) {
    329 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
    330 			kvm_geterr(kd_dump));
    331 		exit(1);
    332 	}
    333 	dumplo += hdrsz;
    334 	kvm_close(kd_kern);
    335 }
    336 
    337 void
    338 check_kmem()
    339 {
    340 	char	*cp;
    341 	long	panicloc;
    342 	char core_vers[1024];
    343 
    344 	(void)kvm_read(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
    345 		sizeof(core_vers));
    346 	core_vers[sizeof(core_vers) - 1] = '\0';
    347 
    348 	if (strcmp(vers, core_vers) && kernel == 0)
    349 		syslog(LOG_WARNING,
    350 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
    351 		    kernel, vers, core_vers);
    352 
    353 	if (KREAD(kd_dump, dump_nl[X_PANICSTR].n_value, &panicstr) != 0) {
    354 		if (verbose)
    355 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    356 		return;
    357 	}
    358 	if (panicstr) {
    359 		cp       = panic_mesg;
    360 		panicloc = panicstr;
    361 		do {
    362 			if (KREAD(kd_dump, panicloc, cp) != 0) {
    363 				if (verbose)
    364 				    syslog(LOG_WARNING, "kvm_read: %s",
    365 					   kvm_geterr(kd_dump));
    366 				break;
    367 			}
    368 			panicloc++;
    369 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
    370 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
    371 	}
    372 }
    373 
    374 int
    375 dump_exists()
    376 {
    377 	int newdumpmag;
    378 
    379 	if (KREAD(kd_dump, dump_nl[X_DUMPMAG].n_value, &newdumpmag) != 0) {
    380 		if (verbose)
    381 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    382 		return (0);
    383 	}
    384 
    385 	/* Read the dump size. */
    386 	if (KREAD(kd_dump, dump_nl[X_DUMPSIZE].n_value, &dumpsize) != 0) {
    387 		if (verbose)
    388 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    389 		return (0);
    390 	}
    391 	dumpsize *= getpagesize();
    392 
    393 	/*
    394 	 * Return zero if core dump doesn't seem to be there, and note
    395 	 * it for syslog.  This check and return happens after the dump size
    396 	 * is read, so dumpsize is whether or not the core is valid (for -f).
    397 	 */
    398 	if (newdumpmag != dumpmag) {
    399 		if (verbose)
    400 			syslog(LOG_WARNING,
    401 			    "magic number mismatch (0x%x != 0x%x)",
    402 			    newdumpmag, dumpmag);
    403 		syslog(LOG_WARNING, "no core dump");
    404 		return (0);
    405 	}
    406 	return (1);
    407 }
    408 
    409 void
    410 clear_dump()
    411 {
    412 	if (kvm_dump_inval(kd_dump) == -1)
    413 		syslog(LOG_ERR, "%s: kvm_clear_dump: %s", ddname,
    414 			kvm_geterr(kd_dump));
    415 
    416 }
    417 
    418 char buf[1024 * 1024];
    419 
    420 void
    421 save_core()
    422 {
    423 	FILE *fp;
    424 	int bounds, ifd, nr, nw, ofd;
    425 	char *rawp, path[MAXPATHLEN];
    426 
    427 	ofd = -1;
    428 	/*
    429 	 * Get the current number and update the bounds file.  Do the update
    430 	 * now, because may fail later and don't want to overwrite anything.
    431 	 */
    432 	umask(066);
    433 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
    434 	if ((fp = fopen(path, "r")) == NULL)
    435 		goto err1;
    436 	if (fgets(buf, sizeof(buf), fp) == NULL) {
    437 		if (ferror(fp))
    438 err1:			syslog(LOG_WARNING, "%s: %s", path, strerror(errno));
    439 		bounds = 0;
    440 	} else
    441 		bounds = atoi(buf);
    442 	if (fp != NULL)
    443 		(void)fclose(fp);
    444 	if ((fp = fopen(path, "w")) == NULL)
    445 		syslog(LOG_ERR, "%s: %m", path);
    446 	else {
    447 		(void)fprintf(fp, "%d\n", bounds + 1);
    448 		(void)fclose(fp);
    449 	}
    450 
    451 	/* Create the core file. */
    452 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
    453 	    dirname, bounds, compress ? ".Z" : "");
    454 	if (compress) {
    455 		if ((fp = zopen(path, "w", 0)) == NULL) {
    456 			syslog(LOG_ERR, "%s: %s", path, strerror(errno));
    457 			exit(1);
    458 		}
    459 	} else {
    460 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    461 		fp  = fdopen(ofd, "w");
    462 		if (fp == NULL) {
    463 			syslog(LOG_ERR, "%s: fdopen: %s", path,
    464 			    strerror(errno));
    465 			exit(1);
    466 		}
    467 	}
    468 
    469 	/* Open the raw device. */
    470 	rawp = rawname(ddname);
    471 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
    472 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
    473 		ifd = dumpfd;
    474 	}
    475 
    476 	/* Seek to the start of the core. */
    477 	Lseek(ifd, (off_t)dumplo, SEEK_SET);
    478 
    479 	if (kvm_dump_wrtheader(kd_dump, fp, dumpsize) == -1) {
    480 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
    481 			kvm_geterr(kd_dump));
    482 		exit(1);
    483 	}
    484 
    485 	/* Copy the core file. */
    486 	syslog(LOG_NOTICE, "writing %score to %s",
    487 	    compress ? "compressed " : "", path);
    488 	for (; dumpsize > 0; dumpsize -= nr) {
    489 		(void)printf("%6dK\r", dumpsize / 1024);
    490 		(void)fflush(stdout);
    491 		nr = read(ifd, buf, MIN(dumpsize, sizeof(buf)));
    492 		if (nr <= 0) {
    493 			if (nr == 0)
    494 				syslog(LOG_WARNING,
    495 				    "WARNING: EOF on dump device");
    496 			else
    497 				syslog(LOG_ERR, "%s: %m", rawp);
    498 			goto err2;
    499 		}
    500 		nw = fwrite(buf, 1, nr, fp);
    501 		if (nw != nr) {
    502 			syslog(LOG_ERR, "%s: %s",
    503 			    path, strerror(nw == 0 ? EIO : errno));
    504 err2:			syslog(LOG_WARNING,
    505 			    "WARNING: core may be incomplete");
    506 			(void)printf("\n");
    507 			exit(1);
    508 		}
    509 	}
    510 	(void)close(ifd);
    511 	(void)fclose(fp);
    512 
    513 	/* Copy the kernel. */
    514 	ifd = Open(kernel ? kernel : _PATH_UNIX, O_RDONLY);
    515 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
    516 	    dirname, bounds, compress ? ".Z" : "");
    517 	if (compress) {
    518 		if ((fp = zopen(path, "w", 0)) == NULL) {
    519 			syslog(LOG_ERR, "%s: %s", path, strerror(errno));
    520 			exit(1);
    521 		}
    522 	} else
    523 		ofd = Create(path, S_IRUSR | S_IWUSR);
    524 	syslog(LOG_NOTICE, "writing %skernel to %s",
    525 	    compress ? "compressed " : "", path);
    526 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
    527 		if (compress)
    528 			nw = fwrite(buf, 1, nr, fp);
    529 		else
    530 			nw = write(ofd, buf, nr);
    531 		if (nw != nr) {
    532 			syslog(LOG_ERR, "%s: %s",
    533 			    path, strerror(nw == 0 ? EIO : errno));
    534 			syslog(LOG_WARNING,
    535 			    "WARNING: kernel may be incomplete");
    536 			exit(1);
    537 		}
    538 	}
    539 	if (nr < 0) {
    540 		syslog(LOG_ERR, "%s: %s",
    541 		    kernel ? kernel : _PATH_UNIX, strerror(errno));
    542 		syslog(LOG_WARNING,
    543 		    "WARNING: kernel may be incomplete");
    544 		exit(1);
    545 	}
    546 	if (compress)
    547 		(void)fclose(fp);
    548 	else
    549 		(void)close(ofd);
    550 }
    551 
    552 char *
    553 find_dev(dev, type)
    554 	dev_t dev;
    555 	int type;
    556 {
    557 	DIR *dfd;
    558 	struct dirent *dir;
    559 	struct stat sb;
    560 	char *dp, devname[MAXPATHLEN + 1];
    561 
    562 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
    563 		syslog(LOG_ERR, "%s: %s", _PATH_DEV, strerror(errno));
    564 		exit(1);
    565 	}
    566 	(void)strcpy(devname, _PATH_DEV);
    567 	while ((dir = readdir(dfd))) {
    568 		(void)strcpy(devname + sizeof(_PATH_DEV) - 1, dir->d_name);
    569 		if (lstat(devname, &sb)) {
    570 			syslog(LOG_ERR, "%s: %s", devname, strerror(errno));
    571 			continue;
    572 		}
    573 		if ((sb.st_mode & S_IFMT) != type)
    574 			continue;
    575 		if (dev == sb.st_rdev) {
    576 			closedir(dfd);
    577 			if ((dp = strdup(devname)) == NULL) {
    578 				syslog(LOG_ERR, "%s", strerror(errno));
    579 				exit(1);
    580 			}
    581 			return (dp);
    582 		}
    583 	}
    584 	closedir(dfd);
    585 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
    586 	exit(1);
    587 }
    588 
    589 char *
    590 rawname(s)
    591 	char *s;
    592 {
    593 	char *sl, name[MAXPATHLEN];
    594 
    595 	if ((sl = strrchr(s, '/')) == NULL || sl[1] == '0') {
    596 		syslog(LOG_ERR,
    597 		    "can't make raw dump device name from %s", s);
    598 		return (s);
    599 	}
    600 	(void)snprintf(name, sizeof(name), "%.*s/r%s", (int)(sl - s), s,
    601 	    sl + 1);
    602 	if ((sl = strdup(name)) == NULL) {
    603 		syslog(LOG_ERR, "%s", strerror(errno));
    604 		exit(1);
    605 	}
    606 	return (sl);
    607 }
    608 
    609 int
    610 get_crashtime()
    611 {
    612 	struct timeval time;
    613 	time_t dumptime;			/* Time the dump was taken. */
    614 
    615 	if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &time) != 0) {
    616 		if (verbose)
    617 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    618 		return (0);
    619 	}
    620 	dumptime = time.tv_sec;
    621 	if (dumptime == 0) {
    622 		if (verbose)
    623 			syslog(LOG_ERR, "dump time is zero");
    624 		return (0);
    625 	}
    626 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
    627 #define	LEEWAY	(7 * SECSPERDAY)
    628 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
    629 		(void)printf("dump time is unreasonable\n");
    630 		return (0);
    631 	}
    632 	return (1);
    633 }
    634 
    635 int
    636 check_space()
    637 {
    638 	FILE *fp;
    639 	off_t minfree, spacefree, kernelsize, needed;
    640 	struct stat st;
    641 	struct statfs fsbuf;
    642 	char buf[100], path[MAXPATHLEN];
    643 
    644 #ifdef __GNUC__
    645 	(void) &minfree;
    646 #endif
    647 
    648 	if (stat(kernel, &st) < 0) {
    649 		syslog(LOG_ERR, "%s: %m", kernel);
    650 		exit(1);
    651 	}
    652 	kernelsize = st.st_blocks * S_BLKSIZE;
    653 	if (statfs(dirname, &fsbuf) < 0) {
    654 		syslog(LOG_ERR, "%s: %m", dirname);
    655 		exit(1);
    656 	}
    657 	spacefree = fsbuf.f_bavail;
    658 	spacefree *= fsbuf.f_bsize;
    659 	spacefree /= 1024;
    660 
    661 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
    662 	if ((fp = fopen(path, "r")) == NULL)
    663 		minfree = 0;
    664 	else {
    665 		if (fgets(buf, sizeof(buf), fp) == NULL)
    666 			minfree = 0;
    667 		else
    668 			minfree = atoi(buf);
    669 		(void)fclose(fp);
    670 	}
    671 
    672 	needed = (dumpsize + kernelsize) / 1024;
    673  	if (minfree > 0 && spacefree - needed < minfree) {
    674 		syslog(LOG_WARNING,
    675 		    "no dump, not enough free space in %s", dirname);
    676 		return (0);
    677 	}
    678 	if (spacefree - needed < minfree)
    679 		syslog(LOG_WARNING,
    680 		    "dump performed, but free space threshold crossed");
    681 	return (1);
    682 }
    683 
    684 int
    685 Open(name, rw)
    686 	char *name;
    687 	int rw;
    688 {
    689 	int fd;
    690 
    691 	if ((fd = open(name, rw, 0)) < 0) {
    692 		syslog(LOG_ERR, "%s: %m", name);
    693 		exit(1);
    694 	}
    695 	return (fd);
    696 }
    697 
    698 void
    699 Lseek(fd, off, flag)
    700 	int fd, flag;
    701 	off_t off;
    702 {
    703 	off_t ret;
    704 
    705 	ret = lseek(fd, off, flag);
    706 	if (ret == -1) {
    707 		syslog(LOG_ERR, "lseek: %m");
    708 		exit(1);
    709 	}
    710 }
    711 
    712 int
    713 Create(file, mode)
    714 	char *file;
    715 	int mode;
    716 {
    717 	int fd;
    718 
    719 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
    720 	if (fd < 0) {
    721 		syslog(LOG_ERR, "%s: %m", file);
    722 		exit(1);
    723 	}
    724 	return (fd);
    725 }
    726 
    727 void
    728 Write(fd, bp, size)
    729 	int fd, size;
    730 	void *bp;
    731 {
    732 	int n;
    733 
    734 	if ((n = write(fd, bp, size)) < size) {
    735 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
    736 		exit(1);
    737 	}
    738 }
    739 
    740 void
    741 usage()
    742 {
    743 	(void)syslog(LOG_ERR, "usage: savecore [-cfvz] [-N system] directory");
    744 	exit(1);
    745 }
    746