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savecore.c revision 1.15
      1 /*-
      2  * Copyright (c) 1986, 1992, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 static char copyright[] =
     36 "@(#) Copyright (c) 1986, 1992, 1993\n\
     37 	The Regents of the University of California.  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 /*static char sccsid[] = "from: @(#)savecore.c	8.3 (Berkeley) 1/2/94";*/
     42 static char *rcsid = "$Id: savecore.c,v 1.15 1994/09/17 00:23:00 mycroft Exp $";
     43 #endif /* not lint */
     44 
     45 #include <sys/param.h>
     46 #include <sys/stat.h>
     47 #include <sys/mount.h>
     48 #include <sys/syslog.h>
     49 #include <sys/time.h>
     50 
     51 #include <dirent.h>
     52 #include <errno.h>
     53 #include <fcntl.h>
     54 #include <nlist.h>
     55 #include <paths.h>
     56 #include <stdio.h>
     57 #include <stdlib.h>
     58 #include <string.h>
     59 #include <tzfile.h>
     60 #include <unistd.h>
     61 
     62 #define ok(number) ((number) - KERNBASE)
     63 
     64 struct nlist current_nl[] = {	/* Namelist for currently running system. */
     65 #define X_DUMPDEV	0
     66 	{ "_dumpdev" },
     67 #define X_DUMPLO	1
     68 	{ "_dumplo" },
     69 #define X_TIME		2
     70 	{ "_time" },
     71 #define	X_DUMPSIZE	3
     72 	{ "_dumpsize" },
     73 #define X_VERSION	4
     74 	{ "_version" },
     75 #define X_PANICSTR	5
     76 	{ "_panicstr" },
     77 #define	X_DUMPMAG	6
     78 	{ "_dumpmag" },
     79 	{ "" },
     80 };
     81 int cursyms[] = { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
     82 int dumpsyms[] = { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
     83 
     84 struct nlist dump_nl[] = {	/* Name list for dumped system. */
     85 	{ "_dumpdev" },		/* Entries MUST be the same as */
     86 	{ "_dumplo" },		/*	those in current_nl[].  */
     87 	{ "_time" },
     88 	{ "_dumpsize" },
     89 	{ "_version" },
     90 	{ "_panicstr" },
     91 	{ "_dumpmag" },
     92 	{ "" },
     93 };
     94 
     95 /* Types match kernel declarations. */
     96 long	dumplo;				/* where dump starts on dumpdev */
     97 int	dumpmag;			/* magic number in dump */
     98 int	dumpsize;			/* amount of memory dumped */
     99 
    100 char	*kernel;
    101 char	*dirname;			/* directory to save dumps in */
    102 char	*ddname;			/* name of dump device */
    103 dev_t	dumpdev;			/* dump device */
    104 int	dumpfd;				/* read/write descriptor on block dev */
    105 time_t	now;				/* current date */
    106 char	panic_mesg[1024];
    107 int	panicstr;
    108 char	vers[1024];
    109 
    110 int	clear, compress, force, verbose;	/* flags */
    111 
    112 void	 check_kmem __P((void));
    113 int	 check_space __P((void));
    114 void	 clear_dump __P((void));
    115 int	 Create __P((char *, int));
    116 int	 dump_exists __P((void));
    117 char	*find_dev __P((dev_t, int));
    118 int	 get_crashtime __P((void));
    119 void	 kmem_setup __P((void));
    120 void	 log __P((int, char *, ...));
    121 void	 Lseek __P((int, off_t, int));
    122 int	 Open __P((char *, int rw));
    123 int	 Read __P((int, void *, int));
    124 char	*rawname __P((char *s));
    125 void	 save_core __P((void));
    126 void	 usage __P((void));
    127 void	 Write __P((int, void *, int));
    128 
    129 int
    130 main(argc, argv)
    131 	int argc;
    132 	char *argv[];
    133 {
    134 	int ch;
    135 
    136 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
    137 
    138 	while ((ch = getopt(argc, argv, "cdfNvz")) != EOF)
    139 		switch(ch) {
    140 		case 'c':
    141 			clear = 1;
    142 			break;
    143 		case 'd':		/* Not documented. */
    144 		case 'v':
    145 			verbose = 1;
    146 			break;
    147 		case 'f':
    148 			force = 1;
    149 			break;
    150 		case 'N':
    151 			kernel = optarg;
    152 			break;
    153 		case 'z':
    154 			compress = 1;
    155 			break;
    156 		case '?':
    157 		default:
    158 			usage();
    159 		}
    160 	argc -= optind;
    161 	argv += optind;
    162 
    163 	if (!clear) {
    164 		if (argc != 1 && argc != 2)
    165 			usage();
    166 		dirname = argv[0];
    167 	}
    168 	if (argc == 2)
    169 		kernel = argv[1];
    170 
    171 	(void)time(&now);
    172 	kmem_setup();
    173 
    174 	if (clear) {
    175 		clear_dump();
    176 		exit(0);
    177 	}
    178 
    179 	if (!dump_exists() && !force)
    180 		exit(1);
    181 
    182 	check_kmem();
    183 
    184 	if (panicstr)
    185 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
    186 	else
    187 		syslog(LOG_ALERT, "reboot");
    188 
    189 	if ((!get_crashtime() || !check_space()) && !force)
    190 		exit(1);
    191 
    192 	save_core();
    193 
    194 	clear_dump();
    195 	exit(0);
    196 }
    197 
    198 void
    199 kmem_setup()
    200 {
    201 	FILE *fp;
    202 	int kmem, i;
    203 	char *dump_sys;
    204 
    205 	/*
    206 	 * Some names we need for the currently running system, others for
    207 	 * the system that was running when the dump was made.  The values
    208 	 * obtained from the current system are used to look for things in
    209 	 * /dev/kmem that cannot be found in the dump_sys namelist, but are
    210 	 * presumed to be the same (since the disk partitions are probably
    211 	 * the same!)
    212 	 */
    213 	if ((nlist(_PATH_UNIX, current_nl)) == -1)
    214 		syslog(LOG_ERR, "%s: nlist: %s", _PATH_UNIX, strerror(errno));
    215 	for (i = 0; cursyms[i] != -1; i++)
    216 		if (current_nl[cursyms[i]].n_value == 0) {
    217 			syslog(LOG_ERR, "%s: %s not in namelist",
    218 			    _PATH_UNIX, current_nl[cursyms[i]].n_name);
    219 			exit(1);
    220 		}
    221 
    222 	dump_sys = kernel ? kernel : _PATH_UNIX;
    223 	if ((nlist(dump_sys, dump_nl)) == -1)
    224 		syslog(LOG_ERR, "%s: nlist: %s", dump_sys, strerror(errno));
    225 	for (i = 0; dumpsyms[i] != -1; i++)
    226 		if (dump_nl[dumpsyms[i]].n_value == 0) {
    227 			syslog(LOG_ERR, "%s: %s not in namelist",
    228 			    dump_sys, dump_nl[dumpsyms[i]].n_name);
    229 			exit(1);
    230 		}
    231 
    232 	kmem = Open(_PATH_KMEM, O_RDONLY);
    233 	Lseek(kmem, (off_t)current_nl[X_DUMPDEV].n_value, L_SET);
    234 	(void)Read(kmem, &dumpdev, sizeof(dumpdev));
    235 	if (dumpdev == NODEV) {
    236 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
    237 		exit(1);
    238 	}
    239 	Lseek(kmem, (off_t)current_nl[X_DUMPLO].n_value, L_SET);
    240 	(void)Read(kmem, &dumplo, sizeof(dumplo));
    241 	if (verbose)
    242 		(void)printf("dumplo = %d (%d * %d)\n",
    243 		    dumplo, dumplo/DEV_BSIZE, DEV_BSIZE);
    244 	Lseek(kmem, (off_t)current_nl[X_DUMPMAG].n_value, L_SET);
    245 	(void)Read(kmem, &dumpmag, sizeof(dumpmag));
    246 	dumplo *= DEV_BSIZE;
    247 	ddname = find_dev(dumpdev, S_IFBLK);
    248 	dumpfd = Open(ddname, O_RDWR);
    249 	fp = fdopen(kmem, "r");
    250 	if (fp == NULL) {
    251 		syslog(LOG_ERR, "%s: fdopen: %m", _PATH_KMEM);
    252 		exit(1);
    253 	}
    254 	if (kernel)
    255 		return;
    256 	(void)fseek(fp, (off_t)current_nl[X_VERSION].n_value, L_SET);
    257 	(void)fgets(vers, sizeof(vers), fp);
    258 
    259 	/* Don't fclose(fp), we use dumpfd later. */
    260 }
    261 
    262 void
    263 check_kmem()
    264 {
    265 	register char *cp;
    266 	FILE *fp;
    267 	char core_vers[1024];
    268 
    269 	fp = fdopen(dumpfd, "r");
    270 	if (fp == NULL) {
    271 		syslog(LOG_ERR, "%s: fdopen: %m", ddname);
    272 		exit(1);
    273 	}
    274 	fseek(fp, (off_t)(dumplo + ok(dump_nl[X_VERSION].n_value)), L_SET);
    275 	fgets(core_vers, sizeof(core_vers), fp);
    276 	if (strcmp(vers, core_vers) && kernel == 0)
    277 		syslog(LOG_WARNING,
    278 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
    279 		    _PATH_UNIX, vers, core_vers);
    280 	(void)fseek(fp,
    281 	    (off_t)(dumplo + ok(dump_nl[X_PANICSTR].n_value)), L_SET);
    282 	(void)fread(&panicstr, sizeof(panicstr), 1, fp);
    283 	if (panicstr) {
    284 		(void)fseek(fp, dumplo + ok(panicstr), L_SET);
    285 		cp = panic_mesg;
    286 		do
    287 			*cp = getc(fp);
    288 		while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)]);
    289 	}
    290 	/* Don't fclose(fp), we use dumpfd later. */
    291 }
    292 
    293 void
    294 clear_dump()
    295 {
    296 	long newdumplo;
    297 
    298 	newdumplo = 0;
    299 	Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
    300 	Write(dumpfd, &newdumplo, sizeof(newdumplo));
    301 }
    302 
    303 int
    304 dump_exists()
    305 {
    306 	int newdumpmag;
    307 
    308 	Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
    309 	(void)Read(dumpfd, &newdumpmag, sizeof(newdumpmag));
    310 	if (newdumpmag != dumpmag) {
    311 		if (verbose)
    312 			syslog(LOG_WARNING, "magic number mismatch (%x != %x)",
    313 			    newdumpmag, dumpmag);
    314 		syslog(LOG_WARNING, "no core dump");
    315 		return (0);
    316 	}
    317 	return (1);
    318 }
    319 
    320 char buf[1024 * 1024];
    321 
    322 void
    323 save_core()
    324 {
    325 	register FILE *fp;
    326 	register int bounds, ifd, nr, nw, ofd;
    327 	char *rawp, path[MAXPATHLEN];
    328 
    329 	/*
    330 	 * Get the current number and update the bounds file.  Do the update
    331 	 * now, because may fail later and don't want to overwrite anything.
    332 	 */
    333 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
    334 	if ((fp = fopen(path, "r")) == NULL)
    335 		goto err1;
    336 	if (fgets(buf, sizeof(buf), fp) == NULL) {
    337 		if (ferror(fp))
    338 err1:			syslog(LOG_WARNING, "%s: %s", path, strerror(errno));
    339 		bounds = 0;
    340 	} else
    341 		bounds = atoi(buf);
    342 	if (fp != NULL)
    343 		(void)fclose(fp);
    344 	if ((fp = fopen(path, "w")) == NULL)
    345 		syslog(LOG_ERR, "%s: %m", path);
    346 	else {
    347 		(void)fprintf(fp, "%d\n", bounds + 1);
    348 		(void)fclose(fp);
    349 	}
    350 	(void)fclose(fp);
    351 
    352 	/* Create the core file. */
    353 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s.core",
    354 	    dirname, bounds, compress ? ".Z" : "");
    355 	if (compress) {
    356 		if ((fp = zopen(path, "w", 0)) == NULL) {
    357 			syslog(LOG_ERR, "%s: %s", path, strerror(errno));
    358 			exit(1);
    359 		}
    360 	} else
    361 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    362 
    363 	/* Open the raw device. */
    364 	rawp = rawname(ddname);
    365 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
    366 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
    367 		ifd = dumpfd;
    368 	}
    369 
    370 	/* Read the dump size. */
    371 	Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPSIZE].n_value)), L_SET);
    372 	(void)Read(dumpfd, &dumpsize, sizeof(dumpsize));
    373 
    374 	/* Seek to the start of the core. */
    375 	Lseek(ifd, (off_t)dumplo, L_SET);
    376 
    377 	/* Copy the core file. */
    378 	dumpsize *= NBPG;
    379 	syslog(LOG_NOTICE, "writing %score to %s",
    380 	    compress ? "compressed " : "", path);
    381 	for (; dumpsize > 0; dumpsize -= nr) {
    382 		(void)printf("%6dK\r", dumpsize / 1024);
    383 		(void)fflush(stdout);
    384 		nr = read(ifd, buf, MIN(dumpsize, sizeof(buf)));
    385 		if (nr <= 0) {
    386 			if (nr == 0)
    387 				syslog(LOG_WARNING,
    388 				    "WARNING: EOF on dump device");
    389 			else
    390 				syslog(LOG_ERR, "%s: %m", rawp);
    391 			goto err2;
    392 		}
    393 		if (compress)
    394 			nw = fwrite(buf, 1, nr, fp);
    395 		else
    396 			nw = write(ofd, buf, nr);
    397 		if (nw != nr) {
    398 			syslog(LOG_ERR, "%s: %s",
    399 			    path, strerror(nw == 0 ? EIO : errno));
    400 err2:			syslog(LOG_WARNING,
    401 			    "WARNING: core may be incomplete");
    402 			(void)printf("\n");
    403 			exit(1);
    404 		}
    405 	}
    406 	(void)printf("\n");
    407 	(void)close(ifd);
    408 	if (compress)
    409 		(void)fclose(fp);
    410 	else
    411 		(void)close(ofd);
    412 
    413 	/* Copy the kernel. */
    414 	ifd = Open(kernel ? kernel : _PATH_UNIX, O_RDONLY);
    415 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
    416 	    dirname, bounds, compress ? ".Z" : "");
    417 	if (compress) {
    418 		if ((fp = zopen(path, "w", 0)) == NULL) {
    419 			syslog(LOG_ERR, "%s: %s", path, strerror(errno));
    420 			exit(1);
    421 		}
    422 	} else
    423 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    424 	syslog(LOG_NOTICE, "writing %skernel to %s",
    425 	    compress ? "compressed " : "", path);
    426 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
    427 		if (compress)
    428 			nw = fwrite(buf, 1, nr, fp);
    429 		else
    430 			nw = write(ofd, buf, nr);
    431 		if (nw != nr) {
    432 			syslog(LOG_ERR, "%s: %s",
    433 			    path, strerror(nw == 0 ? EIO : errno));
    434 			syslog(LOG_WARNING,
    435 			    "WARNING: kernel may be incomplete");
    436 			exit(1);
    437 		}
    438 	}
    439 	if (nr < 0) {
    440 		syslog(LOG_ERR, "%s: %s",
    441 		    kernel ? kernel : _PATH_UNIX, strerror(errno));
    442 		syslog(LOG_WARNING,
    443 		    "WARNING: kernel may be incomplete");
    444 		exit(1);
    445 	}
    446 	if (compress)
    447 		(void)fclose(fp);
    448 	else
    449 		(void)close(ofd);
    450 }
    451 
    452 char *
    453 find_dev(dev, type)
    454 	register dev_t dev;
    455 	register int type;
    456 {
    457 	register DIR *dfd;
    458 	struct dirent *dir;
    459 	struct stat sb;
    460 	char *dp, devname[MAXPATHLEN + 1];
    461 
    462 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
    463 		syslog(LOG_ERR, "%s: %s", _PATH_DEV, strerror(errno));
    464 		exit(1);
    465 	}
    466 	(void)strcpy(devname, _PATH_DEV);
    467 	while ((dir = readdir(dfd))) {
    468 		(void)strcpy(devname + sizeof(_PATH_DEV) - 1, dir->d_name);
    469 		if (lstat(devname, &sb)) {
    470 			syslog(LOG_ERR, "%s: %s", devname, strerror(errno));
    471 			continue;
    472 		}
    473 		if ((sb.st_mode & S_IFMT) != type)
    474 			continue;
    475 		if (dev == sb.st_rdev) {
    476 			closedir(dfd);
    477 			if ((dp = strdup(devname)) == NULL) {
    478 				syslog(LOG_ERR, "%s", strerror(errno));
    479 				exit(1);
    480 			}
    481 			return (dp);
    482 		}
    483 	}
    484 	closedir(dfd);
    485 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
    486 	exit(1);
    487 }
    488 
    489 char *
    490 rawname(s)
    491 	char *s;
    492 {
    493 	char *sl, name[MAXPATHLEN];
    494 
    495 	if ((sl = rindex(s, '/')) == NULL || sl[1] == '0') {
    496 		syslog(LOG_ERR,
    497 		    "can't make raw dump device name from %s", s);
    498 		return (s);
    499 	}
    500 	(void)snprintf(name, sizeof(name), "%.*s/r%s", sl - s, s, sl + 1);
    501 	if ((sl = strdup(name)) == NULL) {
    502 		syslog(LOG_ERR, "%s", strerror(errno));
    503 		exit(1);
    504 	}
    505 	return (sl);
    506 }
    507 
    508 int
    509 get_crashtime()
    510 {
    511 	time_t dumptime;			/* Time the dump was taken. */
    512 
    513 	Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_TIME].n_value)), L_SET);
    514 	(void)Read(dumpfd, &dumptime, sizeof(dumptime));
    515 	if (dumptime == 0) {
    516 		if (verbose)
    517 			syslog(LOG_ERR, "dump time is zero");
    518 		return (0);
    519 	}
    520 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
    521 #define	LEEWAY	(7 * SECSPERDAY)
    522 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
    523 		(void)printf("dump time is unreasonable\n");
    524 		return (0);
    525 	}
    526 	return (1);
    527 }
    528 
    529 int
    530 check_space()
    531 {
    532 	register FILE *fp;
    533 	char *tkernel;
    534 	off_t minfree, spacefree, kernelsize, needed;
    535 	struct stat st;
    536 	struct statfs fsbuf;
    537 	char buf[100], path[MAXPATHLEN];
    538 
    539 	tkernel = kernel ? kernel : _PATH_UNIX;
    540 	if (stat(tkernel, &st) < 0) {
    541 		syslog(LOG_ERR, "%s: %m", tkernel);
    542 		exit(1);
    543 	}
    544 	kernelsize = st.st_blocks * S_BLKSIZE;
    545 	if (statfs(dirname, &fsbuf) < 0) {
    546 		syslog(LOG_ERR, "%s: %m", dirname);
    547 		exit(1);
    548 	}
    549  	spacefree = (fsbuf.f_bavail * fsbuf.f_bsize) / 1024;
    550 
    551 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
    552 	if ((fp = fopen(path, "r")) == NULL)
    553 		minfree = 0;
    554 	else {
    555 		if (fgets(buf, sizeof(buf), fp) == NULL)
    556 			minfree = 0;
    557 		else
    558 			minfree = atoi(buf);
    559 		(void)fclose(fp);
    560 	}
    561 
    562 	needed = (dumpsize + kernelsize) / 1024;
    563  	if (minfree > 0 && spacefree - needed < minfree) {
    564 		syslog(LOG_WARNING,
    565 		    "no dump, not enough free space on device");
    566 		return (0);
    567 	}
    568 	if (spacefree - needed < minfree)
    569 		syslog(LOG_WARNING,
    570 		    "dump performed, but free space threshold crossed");
    571 	return (1);
    572 }
    573 
    574 int
    575 Open(name, rw)
    576 	char *name;
    577 	int rw;
    578 {
    579 	int fd;
    580 
    581 	if ((fd = open(name, rw, 0)) < 0) {
    582 		syslog(LOG_ERR, "%s: %m", name);
    583 		exit(1);
    584 	}
    585 	return (fd);
    586 }
    587 
    588 int
    589 Read(fd, bp, size)
    590 	int fd, size;
    591 	void *bp;
    592 {
    593 	int nr;
    594 
    595 	nr = read(fd, bp, size);
    596 	if (nr != size) {
    597 		syslog(LOG_ERR, "read: %m");
    598 		exit(1);
    599 	}
    600 	return (nr);
    601 }
    602 
    603 void
    604 Lseek(fd, off, flag)
    605 	int fd, flag;
    606 	off_t off;
    607 {
    608 	off_t ret;
    609 
    610 	ret = lseek(fd, off, flag);
    611 	if (ret == -1) {
    612 		syslog(LOG_ERR, "lseek: %m");
    613 		exit(1);
    614 	}
    615 }
    616 
    617 int
    618 Create(file, mode)
    619 	char *file;
    620 	int mode;
    621 {
    622 	register int fd;
    623 
    624 	fd = creat(file, mode);
    625 	if (fd < 0) {
    626 		syslog(LOG_ERR, "%s: %m", file);
    627 		exit(1);
    628 	}
    629 	return (fd);
    630 }
    631 
    632 void
    633 Write(fd, bp, size)
    634 	int fd, size;
    635 	void *bp;
    636 {
    637 	int n;
    638 
    639 	if ((n = write(fd, bp, size)) < size) {
    640 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
    641 		exit(1);
    642 	}
    643 }
    644 
    645 void
    646 usage()
    647 {
    648 	(void)syslog(LOG_ERR, "usage: savecore [-cfvz] [-N system] directory");
    649 	exit(1);
    650 }
    651