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savecore.c revision 1.20
      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 1.20 1995/01/04 05:30:07 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 extern FILE *zopen __P((const char *fname, const char *mode, int bits));
     63 
     64 #define ok(number) ((number) - KERNBASE)
     65 
     66 struct nlist current_nl[] = {	/* Namelist for currently running system. */
     67 #define X_DUMPDEV	0
     68 	{ "_dumpdev" },
     69 #define X_DUMPLO	1
     70 	{ "_dumplo" },
     71 #define X_TIME		2
     72 	{ "_time" },
     73 #define	X_DUMPSIZE	3
     74 	{ "_dumpsize" },
     75 #define X_VERSION	4
     76 	{ "_version" },
     77 #define X_PANICSTR	5
     78 	{ "_panicstr" },
     79 #define	X_DUMPMAG	6
     80 	{ "_dumpmag" },
     81 	{ "" },
     82 };
     83 int cursyms[] = { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
     84 int dumpsyms[] = { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
     85 
     86 struct nlist dump_nl[] = {	/* Name list for dumped system. */
     87 	{ "_dumpdev" },		/* Entries MUST be the same as */
     88 	{ "_dumplo" },		/*	those in current_nl[].  */
     89 	{ "_time" },
     90 	{ "_dumpsize" },
     91 	{ "_version" },
     92 	{ "_panicstr" },
     93 	{ "_dumpmag" },
     94 	{ "" },
     95 };
     96 
     97 /* Types match kernel declarations. */
     98 long	dumplo;				/* where dump starts on dumpdev */
     99 int	dumpmag;			/* magic number in dump */
    100 int	dumpsize;			/* amount of memory dumped */
    101 
    102 char	*kernel;
    103 char	*dirname;			/* directory to save dumps in */
    104 char	*ddname;			/* name of dump device */
    105 dev_t	dumpdev;			/* dump device */
    106 int	dumpfd;				/* read/write descriptor on block dev */
    107 time_t	now;				/* current date */
    108 char	panic_mesg[1024];
    109 int	panicstr;
    110 char	vers[1024];
    111 
    112 int	clear, compress, force, verbose;	/* flags */
    113 
    114 void	 check_kmem __P((void));
    115 int	 check_space __P((void));
    116 void	 clear_dump __P((void));
    117 int	 Create __P((char *, int));
    118 int	 dump_exists __P((void));
    119 char	*find_dev __P((dev_t, int));
    120 int	 get_crashtime __P((void));
    121 void	 kmem_setup __P((void));
    122 void	 log __P((int, char *, ...));
    123 void	 Lseek __P((int, off_t, int));
    124 int	 Open __P((char *, int rw));
    125 int	 Read __P((int, void *, int));
    126 char	*rawname __P((char *s));
    127 void	 save_core __P((void));
    128 void	 usage __P((void));
    129 void	 Write __P((int, void *, int));
    130 
    131 int
    132 main(argc, argv)
    133 	int argc;
    134 	char *argv[];
    135 {
    136 	int ch;
    137 
    138 	openlog("savecore", LOG_PERROR, LOG_DAEMON);
    139 
    140 	while ((ch = getopt(argc, argv, "cdfN:vz")) != -1)
    141 		switch(ch) {
    142 		case 'c':
    143 			clear = 1;
    144 			break;
    145 		case 'd':		/* Not documented. */
    146 		case 'v':
    147 			verbose = 1;
    148 			break;
    149 		case 'f':
    150 			force = 1;
    151 			break;
    152 		case 'N':
    153 			kernel = optarg;
    154 			break;
    155 		case 'z':
    156 			compress = 1;
    157 			break;
    158 		case '?':
    159 		default:
    160 			usage();
    161 		}
    162 	argc -= optind;
    163 	argv += optind;
    164 
    165 	if (!clear) {
    166 		if (argc != 1 && argc != 2)
    167 			usage();
    168 		dirname = argv[0];
    169 	}
    170 	if (argc == 2)
    171 		kernel = argv[1];
    172 
    173 	(void)time(&now);
    174 	kmem_setup();
    175 
    176 	if (clear) {
    177 		clear_dump();
    178 		exit(0);
    179 	}
    180 
    181 	if (!dump_exists() && !force)
    182 		exit(1);
    183 
    184 	check_kmem();
    185 
    186 	if (panicstr)
    187 		syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
    188 	else
    189 		syslog(LOG_ALERT, "reboot");
    190 
    191 	if ((!get_crashtime() || !check_space()) && !force)
    192 		exit(1);
    193 
    194 	save_core();
    195 
    196 	clear_dump();
    197 	exit(0);
    198 }
    199 
    200 void
    201 kmem_setup()
    202 {
    203 	FILE *fp;
    204 	int kmem, i;
    205 	char *dump_sys;
    206 
    207 	/*
    208 	 * Some names we need for the currently running system, others for
    209 	 * the system that was running when the dump was made.  The values
    210 	 * obtained from the current system are used to look for things in
    211 	 * /dev/kmem that cannot be found in the dump_sys namelist, but are
    212 	 * presumed to be the same (since the disk partitions are probably
    213 	 * the same!)
    214 	 */
    215 	if ((nlist(_PATH_UNIX, current_nl)) == -1)
    216 		syslog(LOG_ERR, "%s: nlist: %s", _PATH_UNIX, strerror(errno));
    217 	for (i = 0; cursyms[i] != -1; i++)
    218 		if (current_nl[cursyms[i]].n_value == 0) {
    219 			syslog(LOG_ERR, "%s: %s not in namelist",
    220 			    _PATH_UNIX, current_nl[cursyms[i]].n_name);
    221 			exit(1);
    222 		}
    223 
    224 	dump_sys = kernel ? kernel : _PATH_UNIX;
    225 	if ((nlist(dump_sys, dump_nl)) == -1)
    226 		syslog(LOG_ERR, "%s: nlist: %s", dump_sys, strerror(errno));
    227 	for (i = 0; dumpsyms[i] != -1; i++)
    228 		if (dump_nl[dumpsyms[i]].n_value == 0) {
    229 			syslog(LOG_ERR, "%s: %s not in namelist",
    230 			    dump_sys, dump_nl[dumpsyms[i]].n_name);
    231 			exit(1);
    232 		}
    233 
    234 	kmem = Open(_PATH_KMEM, O_RDONLY);
    235 	Lseek(kmem, (off_t)current_nl[X_DUMPDEV].n_value, L_SET);
    236 	(void)Read(kmem, &dumpdev, sizeof(dumpdev));
    237 	if (dumpdev == NODEV) {
    238 		syslog(LOG_WARNING, "no core dump (no dumpdev)");
    239 		exit(1);
    240 	}
    241 	Lseek(kmem, (off_t)current_nl[X_DUMPLO].n_value, L_SET);
    242 	(void)Read(kmem, &dumplo, sizeof(dumplo));
    243 	if (verbose)
    244 		(void)printf("dumplo = %d (%d * %d)\n",
    245 		    dumplo, dumplo/DEV_BSIZE, DEV_BSIZE);
    246 	Lseek(kmem, (off_t)current_nl[X_DUMPMAG].n_value, L_SET);
    247 	(void)Read(kmem, &dumpmag, sizeof(dumpmag));
    248 	dumplo *= DEV_BSIZE;
    249 	ddname = find_dev(dumpdev, S_IFBLK);
    250 	dumpfd = Open(ddname, O_RDWR);
    251 	fp = fdopen(kmem, "r");
    252 	if (fp == NULL) {
    253 		syslog(LOG_ERR, "%s: fdopen: %m", _PATH_KMEM);
    254 		exit(1);
    255 	}
    256 	if (kernel)
    257 		return;
    258 	(void)fseek(fp, (off_t)current_nl[X_VERSION].n_value, L_SET);
    259 	(void)fgets(vers, sizeof(vers), fp);
    260 
    261 	/* Don't fclose(fp), we use dumpfd later. */
    262 }
    263 
    264 void
    265 check_kmem()
    266 {
    267 	register char *cp;
    268 	FILE *fp;
    269 	char core_vers[1024];
    270 
    271 	fp = fdopen(dumpfd, "r");
    272 	if (fp == NULL) {
    273 		syslog(LOG_ERR, "%s: fdopen: %m", ddname);
    274 		exit(1);
    275 	}
    276 	fseek(fp, (off_t)(dumplo + ok(dump_nl[X_VERSION].n_value)), L_SET);
    277 	fgets(core_vers, sizeof(core_vers), fp);
    278 	if (strcmp(vers, core_vers) && kernel == 0)
    279 		syslog(LOG_WARNING,
    280 		    "warning: %s version mismatch:\n\t%s\nand\t%s\n",
    281 		    _PATH_UNIX, vers, core_vers);
    282 	(void)fseek(fp,
    283 	    (off_t)(dumplo + ok(dump_nl[X_PANICSTR].n_value)), L_SET);
    284 	(void)fread(&panicstr, sizeof(panicstr), 1, fp);
    285 	if (panicstr) {
    286 		(void)fseek(fp, dumplo + ok(panicstr), L_SET);
    287 		cp = panic_mesg;
    288 		do
    289 			*cp = getc(fp);
    290 		while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)]);
    291 	}
    292 	/* Don't fclose(fp), we use dumpfd later. */
    293 }
    294 
    295 void
    296 clear_dump()
    297 {
    298 	long newdumplo;
    299 
    300 	newdumplo = 0;
    301 	Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
    302 	Write(dumpfd, &newdumplo, sizeof(newdumplo));
    303 }
    304 
    305 int
    306 dump_exists()
    307 {
    308 	int newdumpmag;
    309 
    310 	Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
    311 	(void)Read(dumpfd, &newdumpmag, sizeof(newdumpmag));
    312 	if (newdumpmag != dumpmag) {
    313 		if (verbose)
    314 			syslog(LOG_WARNING, "magic number mismatch (%x != %x)",
    315 			    newdumpmag, dumpmag);
    316 		syslog(LOG_WARNING, "no core dump");
    317 		return (0);
    318 	}
    319 	return (1);
    320 }
    321 
    322 char buf[1024 * 1024];
    323 
    324 void
    325 save_core()
    326 {
    327 	register FILE *fp;
    328 	register int bounds, ifd, nr, nw, ofd;
    329 	char *rawp, path[MAXPATHLEN];
    330 
    331 	/*
    332 	 * Get the current number and update the bounds file.  Do the update
    333 	 * now, because may fail later and don't want to overwrite anything.
    334 	 */
    335 	(void)snprintf(path, sizeof(path), "%s/bounds", dirname);
    336 	if ((fp = fopen(path, "r")) == NULL)
    337 		goto err1;
    338 	if (fgets(buf, sizeof(buf), fp) == NULL) {
    339 		if (ferror(fp))
    340 err1:			syslog(LOG_WARNING, "%s: %s", path, strerror(errno));
    341 		bounds = 0;
    342 	} else
    343 		bounds = atoi(buf);
    344 	if (fp != NULL)
    345 		(void)fclose(fp);
    346 	if ((fp = fopen(path, "w")) == NULL)
    347 		syslog(LOG_ERR, "%s: %m", path);
    348 	else {
    349 		(void)fprintf(fp, "%d\n", bounds + 1);
    350 		(void)fclose(fp);
    351 	}
    352 	(void)fclose(fp);
    353 
    354 	/* Create the core file. */
    355 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s.core",
    356 	    dirname, bounds, compress ? ".Z" : "");
    357 	if (compress) {
    358 		if ((fp = zopen(path, "w", 0)) == NULL) {
    359 			syslog(LOG_ERR, "%s: %s", path, strerror(errno));
    360 			exit(1);
    361 		}
    362 	} else
    363 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    364 
    365 	/* Open the raw device. */
    366 	rawp = rawname(ddname);
    367 	if ((ifd = open(rawp, O_RDONLY)) == -1) {
    368 		syslog(LOG_WARNING, "%s: %m; using block device", rawp);
    369 		ifd = dumpfd;
    370 	}
    371 
    372 	/* Read the dump size. */
    373 	Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPSIZE].n_value)), L_SET);
    374 	(void)Read(dumpfd, &dumpsize, sizeof(dumpsize));
    375 
    376 	/* Seek to the start of the core. */
    377 	Lseek(ifd, (off_t)dumplo, L_SET);
    378 
    379 	/* Copy the core file. */
    380 	dumpsize *= getpagesize();
    381 	syslog(LOG_NOTICE, "writing %score to %s",
    382 	    compress ? "compressed " : "", path);
    383 	for (; dumpsize > 0; dumpsize -= nr) {
    384 		(void)printf("%6dK\r", dumpsize / 1024);
    385 		(void)fflush(stdout);
    386 		nr = read(ifd, buf, MIN(dumpsize, sizeof(buf)));
    387 		if (nr <= 0) {
    388 			if (nr == 0)
    389 				syslog(LOG_WARNING,
    390 				    "WARNING: EOF on dump device");
    391 			else
    392 				syslog(LOG_ERR, "%s: %m", rawp);
    393 			goto err2;
    394 		}
    395 		if (compress)
    396 			nw = fwrite(buf, 1, nr, fp);
    397 		else
    398 			nw = write(ofd, buf, nr);
    399 		if (nw != nr) {
    400 			syslog(LOG_ERR, "%s: %s",
    401 			    path, strerror(nw == 0 ? EIO : errno));
    402 err2:			syslog(LOG_WARNING,
    403 			    "WARNING: core may be incomplete");
    404 			(void)printf("\n");
    405 			exit(1);
    406 		}
    407 	}
    408 	(void)printf("\n");
    409 	(void)close(ifd);
    410 	if (compress)
    411 		(void)fclose(fp);
    412 	else
    413 		(void)close(ofd);
    414 
    415 	/* Copy the kernel. */
    416 	ifd = Open(kernel ? kernel : _PATH_UNIX, O_RDONLY);
    417 	(void)snprintf(path, sizeof(path), "%s/netbsd.%d%s",
    418 	    dirname, bounds, compress ? ".Z" : "");
    419 	if (compress) {
    420 		if ((fp = zopen(path, "w", 0)) == NULL) {
    421 			syslog(LOG_ERR, "%s: %s", path, strerror(errno));
    422 			exit(1);
    423 		}
    424 	} else
    425 		ofd = Create(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    426 	syslog(LOG_NOTICE, "writing %skernel to %s",
    427 	    compress ? "compressed " : "", path);
    428 	while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
    429 		if (compress)
    430 			nw = fwrite(buf, 1, nr, fp);
    431 		else
    432 			nw = write(ofd, buf, nr);
    433 		if (nw != nr) {
    434 			syslog(LOG_ERR, "%s: %s",
    435 			    path, strerror(nw == 0 ? EIO : errno));
    436 			syslog(LOG_WARNING,
    437 			    "WARNING: kernel may be incomplete");
    438 			exit(1);
    439 		}
    440 	}
    441 	if (nr < 0) {
    442 		syslog(LOG_ERR, "%s: %s",
    443 		    kernel ? kernel : _PATH_UNIX, strerror(errno));
    444 		syslog(LOG_WARNING,
    445 		    "WARNING: kernel may be incomplete");
    446 		exit(1);
    447 	}
    448 	if (compress)
    449 		(void)fclose(fp);
    450 	else
    451 		(void)close(ofd);
    452 }
    453 
    454 char *
    455 find_dev(dev, type)
    456 	register dev_t dev;
    457 	register int type;
    458 {
    459 	register DIR *dfd;
    460 	struct dirent *dir;
    461 	struct stat sb;
    462 	char *dp, devname[MAXPATHLEN + 1];
    463 
    464 	if ((dfd = opendir(_PATH_DEV)) == NULL) {
    465 		syslog(LOG_ERR, "%s: %s", _PATH_DEV, strerror(errno));
    466 		exit(1);
    467 	}
    468 	(void)strcpy(devname, _PATH_DEV);
    469 	while ((dir = readdir(dfd))) {
    470 		(void)strcpy(devname + sizeof(_PATH_DEV) - 1, dir->d_name);
    471 		if (lstat(devname, &sb)) {
    472 			syslog(LOG_ERR, "%s: %s", devname, strerror(errno));
    473 			continue;
    474 		}
    475 		if ((sb.st_mode & S_IFMT) != type)
    476 			continue;
    477 		if (dev == sb.st_rdev) {
    478 			closedir(dfd);
    479 			if ((dp = strdup(devname)) == NULL) {
    480 				syslog(LOG_ERR, "%s", strerror(errno));
    481 				exit(1);
    482 			}
    483 			return (dp);
    484 		}
    485 	}
    486 	closedir(dfd);
    487 	syslog(LOG_ERR, "can't find device %d/%d", major(dev), minor(dev));
    488 	exit(1);
    489 }
    490 
    491 char *
    492 rawname(s)
    493 	char *s;
    494 {
    495 	char *sl, name[MAXPATHLEN];
    496 
    497 	if ((sl = strrchr(s, '/')) == NULL || sl[1] == '0') {
    498 		syslog(LOG_ERR,
    499 		    "can't make raw dump device name from %s", s);
    500 		return (s);
    501 	}
    502 	(void)snprintf(name, sizeof(name), "%.*s/r%s", sl - s, s, sl + 1);
    503 	if ((sl = strdup(name)) == NULL) {
    504 		syslog(LOG_ERR, "%s", strerror(errno));
    505 		exit(1);
    506 	}
    507 	return (sl);
    508 }
    509 
    510 int
    511 get_crashtime()
    512 {
    513 	time_t dumptime;			/* Time the dump was taken. */
    514 
    515 	Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_TIME].n_value)), L_SET);
    516 	(void)Read(dumpfd, &dumptime, sizeof(dumptime));
    517 	if (dumptime == 0) {
    518 		if (verbose)
    519 			syslog(LOG_ERR, "dump time is zero");
    520 		return (0);
    521 	}
    522 	(void)printf("savecore: system went down at %s", ctime(&dumptime));
    523 #define	LEEWAY	(7 * SECSPERDAY)
    524 	if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
    525 		(void)printf("dump time is unreasonable\n");
    526 		return (0);
    527 	}
    528 	return (1);
    529 }
    530 
    531 int
    532 check_space()
    533 {
    534 	register FILE *fp;
    535 	char *tkernel;
    536 	off_t minfree, spacefree, kernelsize, needed;
    537 	struct stat st;
    538 	struct statfs fsbuf;
    539 	char buf[100], path[MAXPATHLEN];
    540 
    541 	tkernel = kernel ? kernel : _PATH_UNIX;
    542 	if (stat(tkernel, &st) < 0) {
    543 		syslog(LOG_ERR, "%s: %m", tkernel);
    544 		exit(1);
    545 	}
    546 	kernelsize = st.st_blocks * S_BLKSIZE;
    547 	if (statfs(dirname, &fsbuf) < 0) {
    548 		syslog(LOG_ERR, "%s: %m", dirname);
    549 		exit(1);
    550 	}
    551  	spacefree = (fsbuf.f_bavail * fsbuf.f_bsize) / 1024;
    552 
    553 	(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
    554 	if ((fp = fopen(path, "r")) == NULL)
    555 		minfree = 0;
    556 	else {
    557 		if (fgets(buf, sizeof(buf), fp) == NULL)
    558 			minfree = 0;
    559 		else
    560 			minfree = atoi(buf);
    561 		(void)fclose(fp);
    562 	}
    563 
    564 	needed = (dumpsize + kernelsize) / 1024;
    565  	if (minfree > 0 && spacefree - needed < minfree) {
    566 		syslog(LOG_WARNING,
    567 		    "no dump, not enough free space on device");
    568 		return (0);
    569 	}
    570 	if (spacefree - needed < minfree)
    571 		syslog(LOG_WARNING,
    572 		    "dump performed, but free space threshold crossed");
    573 	return (1);
    574 }
    575 
    576 int
    577 Open(name, rw)
    578 	char *name;
    579 	int rw;
    580 {
    581 	int fd;
    582 
    583 	if ((fd = open(name, rw, 0)) < 0) {
    584 		syslog(LOG_ERR, "%s: %m", name);
    585 		exit(1);
    586 	}
    587 	return (fd);
    588 }
    589 
    590 int
    591 Read(fd, bp, size)
    592 	int fd, size;
    593 	void *bp;
    594 {
    595 	int nr;
    596 
    597 	nr = read(fd, bp, size);
    598 	if (nr != size) {
    599 		syslog(LOG_ERR, "read: %m");
    600 		exit(1);
    601 	}
    602 	return (nr);
    603 }
    604 
    605 void
    606 Lseek(fd, off, flag)
    607 	int fd, flag;
    608 	off_t off;
    609 {
    610 	off_t ret;
    611 
    612 	ret = lseek(fd, off, flag);
    613 	if (ret == -1) {
    614 		syslog(LOG_ERR, "lseek: %m");
    615 		exit(1);
    616 	}
    617 }
    618 
    619 int
    620 Create(file, mode)
    621 	char *file;
    622 	int mode;
    623 {
    624 	register int fd;
    625 
    626 	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
    627 	if (fd < 0) {
    628 		syslog(LOG_ERR, "%s: %m", file);
    629 		exit(1);
    630 	}
    631 	return (fd);
    632 }
    633 
    634 void
    635 Write(fd, bp, size)
    636 	int fd, size;
    637 	void *bp;
    638 {
    639 	int n;
    640 
    641 	if ((n = write(fd, bp, size)) < size) {
    642 		syslog(LOG_ERR, "write: %s", strerror(n == -1 ? errno : EIO));
    643 		exit(1);
    644 	}
    645 }
    646 
    647 void
    648 usage()
    649 {
    650 	(void)syslog(LOG_ERR, "usage: savecore [-cfvz] [-N system] directory");
    651 	exit(1);
    652 }
    653