xref: /freebsd/sbin/savecore/savecore.c (revision b3bfc7199eb51b03496567ea71bff82b75a2209d)
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[] = "@(#)savecore.c	8.3 (Berkeley) 1/2/94";
42 #endif /* not lint */
43 
44 #include <sys/param.h>
45 #include <sys/stat.h>
46 #include <sys/mount.h>
47 #include <sys/syslog.h>
48 #include <sys/time.h>
49 
50 #include <vm/vm.h>
51 #include <vm/vm_param.h>
52 
53 #include <dirent.h>
54 #include <errno.h>
55 #include <fcntl.h>
56 #include <nlist.h>
57 #include <paths.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <tzfile.h>
62 #include <unistd.h>
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, "cdfNvz")) != EOF)
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/vmcore.%d%s",
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 *= NBPG;
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: vmcore 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/kernel.%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 = rindex(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 = creat(file, 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