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savecore.c revision 1.48 
      1 /*	$NetBSD: savecore.c,v 1.48 2001/01/02 00:29:37 lukem 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 1.48 2001/01/02 00:29:37 lukem 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 
     56 #include <dirent.h>
     57 #include <errno.h>
     58 #include <fcntl.h>
     59 #include <nlist.h>
     60 #include <paths.h>
     61 #include <stdio.h>
     62 #include <stdlib.h>
     63 #include <string.h>
     64 #include <time.h>
     65 #include <tzfile.h>
     66 #include <unistd.h>
     67 #include <limits.h>
     68 #include <kvm.h>
     69 
     70 extern FILE *zopen(const char *fname, const char *mode, int bits);
     71 
     72 #define KREAD(kd, addr, p)\
     73 	(kvm_read(kd, addr, (char *)(p), sizeof(*(p))) != sizeof(*(p)))
     74 
     75 struct nlist current_nl[] = {	/* Namelist for currently running system. */
     76 #define X_DUMPDEV	0
     77 	{ "_dumpdev" },
     78 #define X_DUMPLO	1
     79 	{ "_dumplo" },
     80 #define X_TIME		2
     81 	{ "_time" },
     82 #define	X_DUMPSIZE	3
     83 	{ "_dumpsize" },
     84 #define X_VERSION	4
     85 	{ "_version" },
     86 #define X_PANICSTR	5
     87 	{ "_panicstr" },
     88 #define	X_DUMPMAG	6
     89 	{ "_dumpmag" },
     90 	{ NULL },
     91 };
     92 int cursyms[] = { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
     93 int dumpsyms[] = { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
     94 
     95 struct nlist dump_nl[] = {	/* Name list for dumped system. */
     96 	{ "_dumpdev" },		/* Entries MUST be the same as */
     97 	{ "_dumplo" },		/*	those in current_nl[].  */
     98 	{ "_time" },
     99 	{ "_dumpsize" },
    100 	{ "_version" },
    101 	{ "_panicstr" },
    102 	{ "_dumpmag" },
    103 	{ NULL },
    104 };
    105 
    106 /* Types match kernel declarations. */
    107 long	dumplo;				/* where dump starts on dumpdev */
    108 int	dumpmag;			/* magic number in dump */
    109 int	dumpsize;			/* amount of memory dumped */
    110 
    111 char	*kernel;			/* name of used kernel */
    112 char	*dirname;			/* directory to save dumps in */
    113 char	*ddname;			/* name of dump device */
    114 dev_t	dumpdev;			/* dump device */
    115 int	dumpfd;				/* read/write descriptor on block dev */
    116 kvm_t	*kd_dump;			/* kvm descriptor on block dev	*/
    117 time_t	now;				/* current date */
    118 char	panic_mesg[1024];
    119 long	panicstr;
    120 char	vers[1024];
    121 
    122 int	clear, compress, force, verbose;	/* flags */
    123 
    124 void	check_kmem(void);
    125 int	check_space(void);
    126 void	clear_dump(void);
    127 int	Create(char *, int);
    128 int	dump_exists(void);
    129 char	*find_dev(dev_t, int);
    130 int	get_crashtime(void);
    131 void	kmem_setup(void);
    132 void	log(int, char *, ...);
    133 void	Lseek(int, off_t, int);
    134 int	main(int, char *[]);
    135 int	Open(char *, int rw);
    136 char	*rawname(char *s);
    137 void	save_core(void);
    138 void	usage(void);
    139 void	Write(int, void *, int);
    140 
    141 int
    142 main(int argc, char *argv[])
    143 {
    144 	int ch;
    145 
    146 	dirname = NULL;
    147 	kernel = NULL;
    148 
    149 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
    150 
    151 	while ((ch = getopt(argc, argv, "cdfN:vz")) != -1)
    152 		switch(ch) {
    153 		case 'c':
    154 			clear = 1;
    155 			break;
    156 		case 'd':		/* Not documented. */
    157 		case 'v':
    158 			verbose = 1;
    159 			break;
    160 		case 'f':
    161 			force = 1;
    162 			break;
    163 		case 'N':
    164 			kernel = optarg;
    165 			break;
    166 		case 'z':
    167 			compress = 1;
    168 			break;
    169 		case '?':
    170 		default:
    171 			usage();
    172 		}
    173 	argc -= optind;
    174 	argv += optind;
    175 
    176 	if (argc != (clear ? 0 : 1))
    177 		usage();
    178 
    179 	if (!clear)
    180 		dirname = argv[0];
    181 
    182 	if (kernel == NULL) {
    183 		kernel = _PATH_UNIX;
    184 	}
    185 
    186 	(void)time(&now);
    187 	kmem_setup();
    188 
    189 	if (clear) {
    190 		clear_dump();
    191 		exit(0);
    192 	}
    193 
    194 	if (!dump_exists() && !force)
    195 		exit(1);
    196 
    197 	check_kmem();
    198 
    199 	if (panicstr)
    200 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
    201 	else
    202 		syslog(LOG_ALERT, "reboot");
    203 
    204 	if ((!get_crashtime() || !check_space()) && !force)
    205 		exit(1);
    206 
    207 	save_core();
    208 
    209 	clear_dump();
    210 	exit(0);
    211 }
    212 
    213 void
    214 kmem_setup(void)
    215 {
    216 	kvm_t *kd_kern;
    217 	char errbuf[_POSIX2_LINE_MAX];
    218 	int i, hdrsz;
    219 
    220 	/*
    221 	 * Some names we need for the currently running system, others for
    222 	 * the system that was running when the dump was made.  The values
    223 	 * obtained from the current system are used to look for things in
    224 	 * /dev/kmem that cannot be found in the kernel namelist, but are
    225 	 * presumed to be the same (since the disk partitions are probably
    226 	 * the same!)
    227 	 */
    228 	kd_kern = kvm_openfiles(kernel, NULL, NULL, O_RDONLY, errbuf);
    229 	if (kd_kern == NULL) {
    230 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    231 		exit(1);
    232 	}
    233 	if (kvm_nlist(kd_kern, current_nl) == -1)
    234 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    235 		    kvm_geterr(kd_kern));
    236 
    237 	for (i = 0; cursyms[i] != -1; i++)
    238 		if (current_nl[cursyms[i]].n_value == 0) {
    239 			syslog(LOG_ERR, "%s: %s not in namelist",
    240 			    kernel, current_nl[cursyms[i]].n_name);
    241 			exit(1);
    242 		}
    243 
    244 	if (KREAD(kd_kern, current_nl[X_DUMPDEV].n_value, &dumpdev) != 0) {
    245 		if (verbose)
    246 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    247 		exit(1);
    248 	}
    249 	if (dumpdev == NODEV) {
    250 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
    251 		exit(1);
    252 	}
    253 	if (KREAD(kd_kern, current_nl[X_DUMPLO].n_value, &dumplo) != 0) {
    254 		if (verbose)
    255 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    256 		exit(1);
    257 	}
    258 	if (dumplo == -1) {
    259 	    syslog(LOG_WARNING, "no core dump (invalid dumplo)");
    260 	    exit(1);
    261 	}
    262 	dumplo *= DEV_BSIZE;
    263 	if (verbose)
    264 		(void)printf("dumplo = %ld (%ld * %ld)\n",
    265 		    (long)dumplo, (long)(dumplo / DEV_BSIZE), (long)DEV_BSIZE);
    266 	if (KREAD(kd_kern, current_nl[X_DUMPMAG].n_value, &dumpmag) != 0) {
    267 		if (verbose)
    268 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_kern));
    269 		exit(1);
    270 	}
    271 
    272 	(void)kvm_read(kd_kern, current_nl[X_VERSION].n_value, vers,
    273 	    sizeof(vers));
    274 	vers[sizeof(vers) - 1] = '\0';
    275 
    276 	ddname = find_dev(dumpdev, S_IFBLK);
    277 	dumpfd = Open(ddname, O_RDWR);
    278 
    279 	kd_dump = kvm_openfiles(kernel, ddname, NULL, O_RDWR, errbuf);
    280 	if (kd_dump == NULL) {
    281 		syslog(LOG_ERR, "%s: kvm_openfiles: %s", kernel, errbuf);
    282 		exit(1);
    283 	}
    284 
    285 	if (kvm_nlist(kd_dump, dump_nl) == -1)
    286 		syslog(LOG_ERR, "%s: kvm_nlist: %s", kernel,
    287 		    kvm_geterr(kd_dump));
    288 
    289 	for (i = 0; dumpsyms[i] != -1; i++)
    290 		if (dump_nl[dumpsyms[i]].n_value == 0) {
    291 			syslog(LOG_ERR, "%s: %s not in namelist",
    292 			    kernel, dump_nl[dumpsyms[i]].n_name);
    293 			exit(1);
    294 		}
    295 	hdrsz = kvm_dump_mkheader(kd_dump, (off_t)dumplo);
    296 
    297 	/*
    298 	 * If 'hdrsz' == 0, kvm_dump_mkheader() failed on the magic-number
    299 	 * checks, ergo no dump is present...
    300 	 */
    301 	if (hdrsz == 0) {
    302 		syslog(LOG_WARNING, "no core dump");
    303 		exit(1);
    304 	}
    305 	if (hdrsz == -1) {
    306 		syslog(LOG_ERR, "%s: kvm_dump_mkheader: %s", kernel,
    307 		    kvm_geterr(kd_dump));
    308 		exit(1);
    309 	}
    310 	dumplo += hdrsz;
    311 	kvm_close(kd_kern);
    312 }
    313 
    314 void
    315 check_kmem(void)
    316 {
    317 	char *cp;
    318 	long panicloc;
    319 	char core_vers[1024];
    320 
    321 	(void)kvm_read(kd_dump, dump_nl[X_VERSION].n_value, core_vers,
    322 	    sizeof(core_vers));
    323 	core_vers[sizeof(core_vers) - 1] = '\0';
    324 
    325 	if (strcmp(vers, core_vers) && kernel == 0)
    326 		syslog(LOG_WARNING,
    327 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
    328 		    kernel, vers, core_vers);
    329 
    330 	if (KREAD(kd_dump, dump_nl[X_PANICSTR].n_value, &panicstr) != 0) {
    331 		if (verbose)
    332 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    333 		return;
    334 	}
    335 	if (panicstr) {
    336 		cp = panic_mesg;
    337 		panicloc = panicstr;
    338 		do {
    339 			if (KREAD(kd_dump, panicloc, cp) != 0) {
    340 				if (verbose)
    341 				    syslog(LOG_WARNING, "kvm_read: %s",
    342 					kvm_geterr(kd_dump));
    343 				break;
    344 			}
    345 			panicloc++;
    346 		} while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)-1]);
    347 		panic_mesg[sizeof(panic_mesg) - 1] = '\0';
    348 	}
    349 }
    350 
    351 int
    352 dump_exists(void)
    353 {
    354 	int newdumpmag;
    355 
    356 	if (KREAD(kd_dump, dump_nl[X_DUMPMAG].n_value, &newdumpmag) != 0) {
    357 		if (verbose)
    358 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    359 		return (0);
    360 	}
    361 
    362 	/* Read the dump size. */
    363 	if (KREAD(kd_dump, dump_nl[X_DUMPSIZE].n_value, &dumpsize) != 0) {
    364 		if (verbose)
    365 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    366 		return (0);
    367 	}
    368 	dumpsize *= getpagesize();
    369 
    370 	/*
    371 	 * Return zero if core dump doesn't seem to be there, and note
    372 	 * it for syslog.  This check and return happens after the dump size
    373 	 * is read, so dumpsize is whether or not the core is valid (for -f).
    374 	 */
    375 	if (newdumpmag != dumpmag) {
    376 		if (verbose)
    377 			syslog(LOG_WARNING,
    378 			    "magic number mismatch (0x%x != 0x%x)",
    379 			    newdumpmag, dumpmag);
    380 		syslog(LOG_WARNING, "no core dump");
    381 		return (0);
    382 	}
    383 	return (1);
    384 }
    385 
    386 void
    387 clear_dump(void)
    388 {
    389 	if (kvm_dump_inval(kd_dump) == -1)
    390 		syslog(LOG_ERR, "%s: kvm_clear_dump: %s", ddname,
    391 		    kvm_geterr(kd_dump));
    392 
    393 }
    394 
    395 char buf[1024 * 1024];
    396 
    397 void
    398 save_core(void)
    399 {
    400 	FILE *fp;
    401 	int bounds, ifd, nr, nw, ofd;
    402 	char *rawp, path[MAXPATHLEN];
    403 
    404 	ofd = -1;
    405 	/*
    406 	 * Get the current number and update the bounds file.  Do the update
    407 	 * now, because may fail later and don't want to overwrite anything.
    408 	 */
    409 	umask(066);
    410 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
    411 	if ((fp = fopen(path, "r")) == NULL)
    412 		goto err1;
    413 	if (fgets(buf, sizeof(buf), fp) == NULL) {
    414 		if (ferror(fp))
    415 err1:			syslog(LOG_WARNING, "%s: %m", path);
    416 		bounds = 0;
    417 	} else
    418 		bounds = atoi(buf);
    419 	if (fp != NULL)
    420 		(void)fclose(fp);
    421 	if ((fp = fopen(path, "w")) == NULL)
    422 		syslog(LOG_ERR, "%s: %m", path);
    423 	else {
    424 		(void)fprintf(fp, "%d\n", bounds + 1);
    425 		(void)fclose(fp);
    426 	}
    427 
    428 	/* Create the core file. */
    429 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d.core%s",
    430 	    dirname, bounds, compress ? ".Z" : "");
    431 	if (compress) {
    432 		if ((fp = zopen(path, "w", 0)) == NULL) {
    433 			syslog(LOG_ERR, "%s: %m", path);
    434 			exit(1);
    435 		}
    436 	} else {
    437 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    438 		fp  = fdopen(ofd, "w");
    439 		if (fp == NULL) {
    440 			syslog(LOG_ERR, "%s: fdopen: %m", path);
    441 			exit(1);
    442 		}
    443 	}
    444 
    445 	/* Open the raw device. */
    446 	rawp = rawname(ddname);
    447 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
    448 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
    449 		ifd = dumpfd;
    450 	}
    451 
    452 	/* Seek to the start of the core. */
    453 	Lseek(ifd, (off_t)dumplo, SEEK_SET);
    454 
    455 	if (kvm_dump_wrtheader(kd_dump, fp, dumpsize) == -1) {
    456 		syslog(LOG_ERR, "kvm_dump_wrtheader: %s : %s", path,
    457 		    kvm_geterr(kd_dump));
    458 		exit(1);
    459 	}
    460 
    461 	/* Copy the core file. */
    462 	syslog(LOG_NOTICE, "writing %score to %s",
    463 	    compress ? "compressed " : "", path);
    464 	for (; dumpsize > 0; dumpsize -= nr) {
    465 		(void)printf("%8dK\r", dumpsize / 1024);
    466 		(void)fflush(stdout);
    467 		nr = read(ifd, buf, MIN(dumpsize, sizeof(buf)));
    468 		if (nr <= 0) {
    469 			if (nr == 0)
    470 				syslog(LOG_WARNING,
    471 				    "WARNING: EOF on dump device");
    472 			else
    473 				syslog(LOG_ERR, "%s: %m", rawp);
    474 			goto err2;
    475 		}
    476 		nw = fwrite(buf, 1, nr, fp);
    477 		if (nw != nr) {
    478 			syslog(LOG_ERR, "%s: %s",
    479 			    path, strerror(nw == 0 ? EIO : errno));
    480 err2:			syslog(LOG_WARNING,
    481 			    "WARNING: core may be incomplete");
    482 			(void)printf("\n");
    483 			exit(1);
    484 		}
    485 	}
    486 	(void)close(ifd);
    487 	(void)fclose(fp);
    488 
    489 	/* Copy the kernel. */
    490 	ifd = Open(kernel ? kernel : _PATH_UNIX, O_RDONLY);
    491 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
    492 	    dirname, bounds, compress ? ".Z" : "");
    493 	if (compress) {
    494 		if ((fp = zopen(path, "w", 0)) == NULL) {
    495 			syslog(LOG_ERR, "%s: %m", path);
    496 			exit(1);
    497 		}
    498 	} else
    499 		ofd = Create(path, S_IRUSR | S_IWUSR);
    500 	syslog(LOG_NOTICE, "writing %skernel to %s",
    501 	    compress ? "compressed " : "", path);
    502 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
    503 		if (compress)
    504 			nw = fwrite(buf, 1, nr, fp);
    505 		else
    506 			nw = write(ofd, buf, nr);
    507 		if (nw != nr) {
    508 			syslog(LOG_ERR, "%s: %s",
    509 			    path, strerror(nw == 0 ? EIO : errno));
    510 			syslog(LOG_WARNING,
    511 			    "WARNING: kernel may be incomplete");
    512 			exit(1);
    513 		}
    514 	}
    515 	if (nr < 0) {
    516 		syslog(LOG_ERR, "%s: %m", kernel ? kernel : _PATH_UNIX);
    517 		syslog(LOG_WARNING, "WARNING: kernel may be incomplete");
    518 		exit(1);
    519 	}
    520 	if (compress)
    521 		(void)fclose(fp);
    522 	else
    523 		(void)close(ofd);
    524 }
    525 
    526 char *
    527 find_dev(dev_t dev, int type)
    528 {
    529 	DIR *dfd;
    530 	struct dirent *dir;
    531 	struct stat sb;
    532 	char *dp, devname[MAXPATHLEN + 1];
    533 
    534 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
    535 		syslog(LOG_ERR, "%s: %m", _PATH_DEV);
    536 		exit(1);
    537 	}
    538 	(void)strcpy(devname, _PATH_DEV);
    539 	while ((dir = readdir(dfd))) {
    540 		(void)strcpy(devname + sizeof(_PATH_DEV) - 1, dir->d_name);
    541 		if (lstat(devname, &sb)) {
    542 			syslog(LOG_ERR, "%s: %m", devname);
    543 			continue;
    544 		}
    545 		if ((sb.st_mode & S_IFMT) != type)
    546 			continue;
    547 		if (dev == sb.st_rdev) {
    548 			closedir(dfd);
    549 			if ((dp = strdup(devname)) == NULL) {
    550 				syslog(LOG_ERR, "%m");
    551 				exit(1);
    552 			}
    553 			return (dp);
    554 		}
    555 	}
    556 	closedir(dfd);
    557 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
    558 	exit(1);
    559 }
    560 
    561 char *
    562 rawname(char *s)
    563 {
    564 	char *sl;
    565 	char name[MAXPATHLEN];
    566 
    567 	if ((sl = strrchr(s, '/')) == NULL || sl[1] == '0') {
    568 		syslog(LOG_ERR,
    569 		    "can't make raw dump device name from %s", s);
    570 		return (s);
    571 	}
    572 	(void)snprintf(name, sizeof(name), "%.*s/r%s", (int)(sl - s), s,
    573 	    sl + 1);
    574 	if ((sl = strdup(name)) == NULL) {
    575 		syslog(LOG_ERR, "%m");
    576 		exit(1);
    577 	}
    578 	return (sl);
    579 }
    580 
    581 int
    582 get_crashtime(void)
    583 {
    584 	struct timeval dtime;
    585 	time_t dumptime;			/* Time the dump was taken. */
    586 
    587 	if (KREAD(kd_dump, dump_nl[X_TIME].n_value, &dtime) != 0) {
    588 		if (verbose)
    589 		    syslog(LOG_WARNING, "kvm_read: %s", kvm_geterr(kd_dump));
    590 		return (0);
    591 	}
    592 	dumptime = dtime.tv_sec;
    593 	if (dumptime == 0) {
    594 		if (verbose)
    595 			syslog(LOG_ERR, "dump time is zero");
    596 		return (0);
    597 	}
    598 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
    599 #define	LEEWAY	(7 * SECSPERDAY)
    600 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
    601 		(void)printf("dump time is unreasonable\n");
    602 		return (0);
    603 	}
    604 	return (1);
    605 }
    606 
    607 int
    608 check_space(void)
    609 {
    610 	FILE *fp;
    611 	off_t minfree, spacefree, kernelsize, needed;
    612 	struct stat st;
    613 	struct statfs fsbuf;
    614 	char mbuf[100], path[MAXPATHLEN];
    615 
    616 #ifdef __GNUC__
    617 	(void) &minfree;
    618 #endif
    619 
    620 	if (stat(kernel, &st) < 0) {
    621 		syslog(LOG_ERR, "%s: %m", kernel);
    622 		exit(1);
    623 	}
    624 	kernelsize = st.st_blocks * S_BLKSIZE;
    625 	if (statfs(dirname, &fsbuf) < 0) {
    626 		syslog(LOG_ERR, "%s: %m", dirname);
    627 		exit(1);
    628 	}
    629 	spacefree = fsbuf.f_bavail;
    630 	spacefree *= fsbuf.f_bsize;
    631 	spacefree /= 1024;
    632 
    633 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
    634 	if ((fp = fopen(path, "r")) == NULL)
    635 		minfree = 0;
    636 	else {
    637 		if (fgets(mbuf, sizeof(mbuf), fp) == NULL)
    638 			minfree = 0;
    639 		else
    640 			minfree = atoi(mbuf);
    641 		(void)fclose(fp);
    642 	}
    643 
    644 	needed = (dumpsize + kernelsize) / 1024;
    645  	if (minfree > 0 && spacefree - needed < minfree) {
    646 		syslog(LOG_WARNING,
    647 		    "no dump, not enough free space in %s", dirname);
    648 		return (0);
    649 	}
    650 	if (spacefree - needed < minfree)
    651 		syslog(LOG_WARNING,
    652 		    "dump performed, but free space threshold crossed");
    653 	return (1);
    654 }
    655 
    656 int
    657 Open(char *name, int rw)
    658 {
    659 	int fd;
    660 
    661 	if ((fd = open(name, rw, 0)) < 0) {
    662 		syslog(LOG_ERR, "%s: %m", name);
    663 		exit(1);
    664 	}
    665 	return (fd);
    666 }
    667 
    668 void
    669 Lseek(int fd, off_t off, int flag)
    670 {
    671 	off_t ret;
    672 
    673 	ret = lseek(fd, off, flag);
    674 	if (ret == -1) {
    675 		syslog(LOG_ERR, "lseek: %m");
    676 		exit(1);
    677 	}
    678 }
    679 
    680 int
    681 Create(char *file, int mode)
    682 {
    683 	int fd;
    684 
    685 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
    686 	if (fd < 0) {
    687 		syslog(LOG_ERR, "%s: %m", file);
    688 		exit(1);
    689 	}
    690 	return (fd);
    691 }
    692 
    693 void
    694 Write(int fd, void *bp, int size)
    695 {
    696 	int n;
    697 
    698 	if ((n = write(fd, bp, size)) < size) {
    699 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
    700 		exit(1);
    701 	}
    702 }
    703 
    704 void
    705 usage(void)
    706 {
    707 	(void)syslog(LOG_ERR, "usage: savecore [-cfvz] [-N system] directory");
    708 	exit(1);
    709 }
    710