xref: /freebsd/sbin/fsck_ffs/main.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 1986, 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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #if 0
33 #ifndef lint
34 static const char copyright[] =
35 "@(#) Copyright (c) 1980, 1986, 1993\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif /* not lint */
38 
39 #ifndef lint
40 static char sccsid[] = "@(#)main.c	8.6 (Berkeley) 5/14/95";
41 #endif /* not lint */
42 #endif
43 #include <sys/cdefs.h>
44 #define _WANT_P_OSREL
45 #include <sys/param.h>
46 #include <sys/file.h>
47 #include <sys/mount.h>
48 #include <sys/resource.h>
49 #include <sys/stat.h>
50 #include <sys/sysctl.h>
51 #include <sys/uio.h>
52 #include <sys/disklabel.h>
53 
54 #include <ufs/ufs/dinode.h>
55 #include <ufs/ffs/fs.h>
56 
57 #include <err.h>
58 #include <errno.h>
59 #include <fstab.h>
60 #include <grp.h>
61 #include <inttypes.h>
62 #include <libufs.h>
63 #include <mntopts.h>
64 #include <paths.h>
65 #include <stdint.h>
66 #include <string.h>
67 #include <time.h>
68 
69 #include "fsck.h"
70 
71 static int	restarts;
72 
73 static void usage(void) __dead2;
74 static intmax_t argtoimax(int flag, const char *req, const char *str, int base);
75 static int checkfilesys(char *filesys);
76 static int setup_bkgrdchk(struct statfs *mntp, int sbrdfailed, char **filesys);
77 
78 int
79 main(int argc, char *argv[])
80 {
81 	int ch;
82 	struct rlimit rlimit;
83 	struct itimerval itimerval;
84 	int fsret;
85 	int ret = 0;
86 
87 	sync();
88 	skipclean = 1;
89 	inoopt = 0;
90 	while ((ch = getopt(argc, argv, "b:Bc:CdEfFm:npRrSyZz")) != -1) {
91 		switch (ch) {
92 		case 'b':
93 			skipclean = 0;
94 			bflag = argtoimax('b', "number", optarg, 10);
95 			printf("Alternate super block location: %jd\n", bflag);
96 			break;
97 
98 		case 'B':
99 			bkgrdflag = 1;
100 			break;
101 
102 		case 'c':
103 			skipclean = 0;
104 			cvtlevel = argtoimax('c', "conversion level", optarg,
105 			    10);
106 			if (cvtlevel < 3)
107 				errx(EEXIT, "cannot do level %d conversion",
108 				    cvtlevel);
109 			break;
110 
111 		case 'd':
112 			debug++;
113 			break;
114 
115 		case 'E':
116 			Eflag++;
117 			break;
118 
119 		case 'f':
120 			skipclean = 0;
121 			break;
122 
123 		case 'F':
124 			bkgrdcheck = 1;
125 			break;
126 
127 		case 'm':
128 			lfmode = argtoimax('m', "mode", optarg, 8);
129 			if (lfmode &~ 07777)
130 				errx(EEXIT, "bad mode to -m: %o", lfmode);
131 			printf("** lost+found creation mode %o\n", lfmode);
132 			break;
133 
134 		case 'n':
135 			nflag++;
136 			yflag = 0;
137 			break;
138 
139 		case 'p':
140 			preen++;
141 			/*FALLTHROUGH*/
142 
143 		case 'C':
144 			ckclean++;
145 			break;
146 
147 		case 'R':
148 			wantrestart = 1;
149 			break;
150 		case 'r':
151 			inoopt++;
152 			break;
153 
154 		case 'S':
155 			surrender = 1;
156 			break;
157 
158 		case 'y':
159 			yflag++;
160 			nflag = 0;
161 			break;
162 
163 		case 'Z':
164 			Zflag++;
165 			break;
166 
167 		case 'z':
168 			zflag++;
169 			break;
170 
171 		default:
172 			usage();
173 		}
174 	}
175 	argc -= optind;
176 	argv += optind;
177 
178 	if (!argc)
179 		usage();
180 
181 	if (bkgrdflag && cvtlevel > 0) {
182 		pfatal("CANNOT CONVERT A SNAPSHOT\n");
183 		exit(EEXIT);
184 	}
185 
186 	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
187 		(void)signal(SIGINT, catch);
188 	if (ckclean)
189 		(void)signal(SIGQUIT, catchquit);
190 	signal(SIGINFO, infohandler);
191 	if (bkgrdflag) {
192 		signal(SIGALRM, alarmhandler);
193 		itimerval.it_interval.tv_sec = 5;
194 		itimerval.it_interval.tv_usec = 0;
195 		itimerval.it_value.tv_sec = 5;
196 		itimerval.it_value.tv_usec = 0;
197 		setitimer(ITIMER_REAL, &itimerval, NULL);
198 	}
199 	/*
200 	 * Push up our allowed memory limit so we can cope
201 	 * with huge file systems.
202 	 */
203 	if (getrlimit(RLIMIT_DATA, &rlimit) == 0) {
204 		rlimit.rlim_cur = rlimit.rlim_max;
205 		(void)setrlimit(RLIMIT_DATA, &rlimit);
206 	}
207 	while (argc > 0) {
208 		if ((fsret = checkfilesys(*argv)) == ERESTART)
209 			continue;
210 		ret |= fsret;
211 		argc--;
212 		argv++;
213 	}
214 
215 	if (returntosingle)
216 		ret = 2;
217 	exit(ret);
218 }
219 
220 static intmax_t
221 argtoimax(int flag, const char *req, const char *str, int base)
222 {
223 	char *cp;
224 	intmax_t ret;
225 
226 	ret = strtoimax(str, &cp, base);
227 	if (cp == str || *cp)
228 		errx(EEXIT, "-%c flag requires a %s", flag, req);
229 	return (ret);
230 }
231 
232 /*
233  * Check the specified file system.
234  */
235 /* ARGSUSED */
236 static int
237 checkfilesys(char *filesys)
238 {
239 	ufs2_daddr_t n_ffree, n_bfree;
240 	struct dups *dp;
241 	struct statfs *mntp;
242 	intmax_t blks, files;
243 	size_t size;
244 	int sbreadfailed, ofsmodified;
245 
246 	fsutilinit();
247 	fsckinit();
248 
249 	cdevname = filesys;
250 	if (debug && ckclean)
251 		pwarn("starting\n");
252 	/*
253 	 * Make best effort to get the disk name. Check first to see
254 	 * if it is listed among the mounted file systems. Failing that
255 	 * check to see if it is listed in /etc/fstab.
256 	 */
257 	mntp = getmntpoint(filesys);
258 	if (mntp != NULL)
259 		filesys = mntp->f_mntfromname;
260 	else
261 		filesys = blockcheck(filesys);
262 	/*
263 	 * If -F flag specified, check to see whether a background check
264 	 * is possible and needed. If possible and needed, exit with
265 	 * status zero. Otherwise exit with status non-zero. A non-zero
266 	 * exit status will cause a foreground check to be run.
267 	 */
268 	sblock_init();
269 	sbreadfailed = 0;
270 	if (openfilesys(filesys) == 0 || readsb() == 0)
271 		sbreadfailed = 1;
272 	if (bkgrdcheck) {
273 		if (sbreadfailed)
274 			exit(3);	/* Cannot read superblock */
275 		if ((sblock.fs_flags & FS_NEEDSFSCK) == FS_NEEDSFSCK)
276 			exit(4);	/* Earlier background failed */
277 		if ((sblock.fs_flags & FS_SUJ) == FS_SUJ) {
278 			maxino = sblock.fs_ncg * sblock.fs_ipg;
279 			maxfsblock = sblock.fs_size;
280 			bufinit();
281 			preen = 1;
282 			if (suj_check(filesys) == 0)
283 				exit(4); /* Journal good, run it now */
284 		}
285 		if ((sblock.fs_flags & FS_DOSOFTDEP) == 0)
286 			exit(5);	/* Not running soft updates */
287 		size = MIBSIZE;
288 		if (sysctlnametomib("vfs.ffs.adjrefcnt", adjrefcnt, &size) < 0)
289 			exit(6);	/* Lacks kernel support */
290 		if ((mntp == NULL && sblock.fs_clean == 1) ||
291 		    (mntp != NULL && (sblock.fs_flags & FS_UNCLEAN) == 0))
292 			exit(7);	/* Filesystem clean, report it now */
293 		exit(0);
294 	}
295 	if (ckclean && skipclean) {
296 		/*
297 		 * If file system is gjournaled, check it here.
298 		 */
299 		if (sbreadfailed)
300 			exit(3);	/* Cannot read superblock */
301 		if (bkgrdflag == 0 &&
302 		    (nflag || (fswritefd = open(filesys, O_WRONLY)) < 0)) {
303 			fswritefd = -1;
304 			if (preen)
305 				pfatal("NO WRITE ACCESS");
306 			printf(" (NO WRITE)");
307 		}
308 		if ((sblock.fs_flags & FS_GJOURNAL) != 0) {
309 			if (sblock.fs_clean == 1) {
310 				pwarn("FILE SYSTEM CLEAN; SKIPPING CHECKS\n");
311 				exit(0);
312 			}
313 			if ((sblock.fs_flags &
314 			    (FS_UNCLEAN | FS_NEEDSFSCK)) == 0) {
315 				bufinit();
316 				gjournal_check(filesys);
317 				if (chkdoreload(mntp, pwarn) == 0)
318 					exit(0);
319 				exit(4);
320 			} else {
321 				pfatal("FULL FSCK NEEDED, CANNOT RUN FAST "
322 				    "FSCK\n");
323 			}
324 		}
325 		close(fswritefd);
326 		fswritefd = -1;
327 	}
328 	if (bkgrdflag) {
329 		switch (setup_bkgrdchk(mntp, sbreadfailed, &filesys)) {
330 		case -1: /* filesystem clean */
331 			goto clean;
332 		case 0: /* cannot do background, give up */
333 			exit(EEXIT);
334 		case 1: /* doing background check, preen rules apply */
335 			preen = 1;
336 			break;
337 		}
338 	}
339 
340 	switch (setup(filesys)) {
341 	case 0:
342 		if (preen)
343 			pfatal("CAN'T CHECK FILE SYSTEM.");
344 		return (EEXIT);
345 	case -1:
346 	clean:
347 		pwarn("clean, %ld free ", (long)(sblock.fs_cstotal.cs_nffree +
348 		    sblock.fs_frag * sblock.fs_cstotal.cs_nbfree));
349 		printf("(%jd frags, %jd blocks, %.1f%% fragmentation)\n",
350 		    (intmax_t)sblock.fs_cstotal.cs_nffree,
351 		    (intmax_t)sblock.fs_cstotal.cs_nbfree,
352 		    sblock.fs_cstotal.cs_nffree * 100.0 / sblock.fs_dsize);
353 		return (0);
354 	}
355 	/*
356 	 * Determine if we can and should do journal recovery.
357 	 */
358 	if (bkgrdflag == 0 && (sblock.fs_flags & FS_SUJ) == FS_SUJ) {
359 		if ((sblock.fs_flags & FS_NEEDSFSCK) != FS_NEEDSFSCK &&
360 		    skipclean) {
361 			sujrecovery = 1;
362 			if (suj_check(filesys) == 0) {
363 				pwarn("\n**** FILE SYSTEM MARKED CLEAN ****\n");
364 				if (chkdoreload(mntp, pwarn) == 0)
365 					exit(0);
366 				exit(4);
367 			}
368 			sujrecovery = 0;
369 			pwarn("Skipping journal, "
370 			    "falling through to full fsck\n");
371 		}
372 		if (fswritefd != -1) {
373 			/*
374 			 * Write the superblock so we don't try to recover the
375 			 * journal on another pass. If this is the only change
376 			 * to the filesystem, we do not want it to be called
377 			 * out as modified.
378 			 */
379 			sblock.fs_mtime = time(NULL);
380 			sbdirty();
381 			ofsmodified = fsmodified;
382 			flush(fswritefd, &sblk);
383 			fsmodified = ofsmodified;
384 		}
385 	}
386 	/*
387 	 * If the filesystem was run on an old kernel that did not
388 	 * support check hashes, clear the check-hash flags so that
389 	 * we do not try to verify them.
390 	 */
391 	if ((sblock.fs_flags & FS_METACKHASH) == 0)
392 		sblock.fs_metackhash = 0;
393 	/*
394 	 * If we are running on a kernel that can provide check hashes
395 	 * that are not yet enabled for the filesystem and we are
396 	 * running manually without the -y flag, offer to add any
397 	 * supported check hashes that are not already enabled.
398 	 */
399 	ckhashadd = 0;
400 	if (preen == 0 && yflag == 0 && sblock.fs_magic != FS_UFS1_MAGIC &&
401 	    fswritefd != -1 && getosreldate() >= P_OSREL_CK_CYLGRP) {
402 		if ((sblock.fs_metackhash & CK_CYLGRP) == 0 &&
403 		    reply("ADD CYLINDER GROUP CHECK-HASH PROTECTION") != 0) {
404 			ckhashadd |= CK_CYLGRP;
405 			sblock.fs_metackhash |= CK_CYLGRP;
406 		}
407 		if ((sblock.fs_metackhash & CK_SUPERBLOCK) == 0 &&
408 		    getosreldate() >= P_OSREL_CK_SUPERBLOCK &&
409 		    reply("ADD SUPERBLOCK CHECK-HASH PROTECTION") != 0) {
410 			ckhashadd |= CK_SUPERBLOCK;
411 			sblock.fs_metackhash |= CK_SUPERBLOCK;
412 		}
413 		if ((sblock.fs_metackhash & CK_INODE) == 0 &&
414 		    getosreldate() >= P_OSREL_CK_INODE &&
415 		    reply("ADD INODE CHECK-HASH PROTECTION") != 0) {
416 			ckhashadd |= CK_INODE;
417 			sblock.fs_metackhash |= CK_INODE;
418 		}
419 #ifdef notyet
420 		if ((sblock.fs_metackhash & CK_INDIR) == 0 &&
421 		    getosreldate() >= P_OSREL_CK_INDIR &&
422 		    reply("ADD INDIRECT BLOCK CHECK-HASH PROTECTION") != 0) {
423 			ckhashadd |= CK_INDIR;
424 			sblock.fs_metackhash |= CK_INDIR;
425 		}
426 		if ((sblock.fs_metackhash & CK_DIR) == 0 &&
427 		    getosreldate() >= P_OSREL_CK_DIR &&
428 		    reply("ADD DIRECTORY CHECK-HASH PROTECTION") != 0) {
429 			ckhashadd |= CK_DIR;
430 			sblock.fs_metackhash |= CK_DIR;
431 		}
432 #endif /* notyet */
433 		if (ckhashadd != 0) {
434 			sblock.fs_flags |= FS_METACKHASH;
435 			sbdirty();
436 		}
437 	}
438 	/*
439 	 * Cleared if any questions answered no. Used to decide if
440 	 * the superblock should be marked clean.
441 	 */
442 	resolved = 1;
443 	/*
444 	 * 1: scan inodes tallying blocks used
445 	 */
446 	if (preen == 0 || debug) {
447 		printf("** Last Mounted on %s\n", sblock.fs_fsmnt);
448 		if (mntp != NULL && mntp->f_flags & MNT_ROOTFS)
449 			printf("** Root file system\n");
450 		printf("** Phase 1 - Check Blocks and Sizes\n");
451 	}
452 	clock_gettime(CLOCK_REALTIME_PRECISE, &startprog);
453 	pass1();
454 	IOstats("Pass1");
455 
456 	/*
457 	 * 1b: locate first references to duplicates, if any
458 	 */
459 	if (duplist) {
460 		if (preen || usedsoftdep)
461 			pfatal("INTERNAL ERROR: DUPS WITH %s%s%s",
462 			    preen ? "-p" : "",
463 			    (preen && usedsoftdep) ? " AND " : "",
464 			    usedsoftdep ? "SOFTUPDATES" : "");
465 		if (preen == 0 || debug)
466 			printf("** Phase 1b - Rescan For More DUPS\n");
467 		pass1b();
468 		IOstats("Pass1b");
469 	}
470 
471 	/*
472 	 * 2: traverse directories from root to mark all connected directories
473 	 */
474 	if (preen == 0 || debug)
475 		printf("** Phase 2 - Check Pathnames\n");
476 	pass2();
477 	IOstats("Pass2");
478 
479 	/*
480 	 * 3: scan inodes looking for disconnected directories
481 	 */
482 	if (preen == 0 || debug)
483 		printf("** Phase 3 - Check Connectivity\n");
484 	pass3();
485 	IOstats("Pass3");
486 
487 	/*
488 	 * 4: scan inodes looking for disconnected files; check reference counts
489 	 */
490 	if (preen == 0 || debug)
491 		printf("** Phase 4 - Check Reference Counts\n");
492 	pass4();
493 	IOstats("Pass4");
494 
495 	/*
496 	 * 5: check and repair resource counts in cylinder groups
497 	 */
498 	if (preen == 0 || debug)
499 		printf("** Phase 5 - Check Cyl groups\n");
500 	snapflush(std_checkblkavail);
501 	if (cgheader_corrupt) {
502 		printf("PHASE 5 SKIPPED DUE TO CORRUPT CYLINDER GROUP "
503 		    "HEADER(S)\n\n");
504 	} else {
505 		pass5();
506 		IOstats("Pass5");
507 	}
508 
509 	/*
510 	 * print out summary statistics
511 	 */
512 	n_ffree = sblock.fs_cstotal.cs_nffree;
513 	n_bfree = sblock.fs_cstotal.cs_nbfree;
514 	files = maxino - UFS_ROOTINO - sblock.fs_cstotal.cs_nifree - n_files;
515 	blks = n_blks +
516 	    sblock.fs_ncg * (cgdmin(&sblock, 0) - cgsblock(&sblock, 0));
517 	blks += cgsblock(&sblock, 0) - cgbase(&sblock, 0);
518 	blks += howmany(sblock.fs_cssize, sblock.fs_fsize);
519 	blks = maxfsblock - (n_ffree + sblock.fs_frag * n_bfree) - blks;
520 	if (bkgrdflag && (files > 0 || blks > 0)) {
521 		countdirs = sblock.fs_cstotal.cs_ndir - countdirs;
522 		pwarn("Reclaimed: %ld directories, %jd files, %jd fragments\n",
523 		    countdirs, files - countdirs, blks);
524 	}
525 	pwarn("%ld files, %jd used, %ju free ",
526 	    (long)n_files, (intmax_t)n_blks,
527 	    (uintmax_t)n_ffree + sblock.fs_frag * n_bfree);
528 	printf("(%ju frags, %ju blocks, %.1f%% fragmentation)\n",
529 	    (uintmax_t)n_ffree, (uintmax_t)n_bfree,
530 	    n_ffree * 100.0 / sblock.fs_dsize);
531 	if (debug) {
532 		if (files < 0)
533 			printf("%jd inodes missing\n", -files);
534 		if (blks < 0)
535 			printf("%jd blocks missing\n", -blks);
536 		if (duplist != NULL) {
537 			printf("The following duplicate blocks remain:");
538 			for (dp = duplist; dp; dp = dp->next)
539 				printf(" %jd,", (intmax_t)dp->dup);
540 			printf("\n");
541 		}
542 	}
543 	duplist = (struct dups *)0;
544 	muldup = (struct dups *)0;
545 	inocleanup();
546 	if (fsmodified) {
547 		sblock.fs_time = time(NULL);
548 		sbdirty();
549 	}
550 	if (cvtlevel && (sblk.b_flags & B_DIRTY) != 0) {
551 		/*
552 		 * Write out the duplicate super blocks
553 		 */
554 		if (sbput(fswritefd, &sblock, sblock.fs_ncg) == 0)
555 			fsmodified = 1;
556 	}
557 	if (rerun)
558 		resolved = 0;
559 
560 	/*
561 	 * Check to see if the file system is mounted read-write.
562 	 */
563 	if (bkgrdflag == 0 && mntp != NULL && (mntp->f_flags & MNT_RDONLY) == 0)
564 		resolved = 0;
565 	ckfini(resolved);
566 
567 	if (fsmodified && !preen)
568 		printf("\n***** FILE SYSTEM WAS MODIFIED *****\n");
569 	if (rerun) {
570 		if (wantrestart && (restarts++ < 10) &&
571 		    (preen || reply("RESTART")))
572 			return (ERESTART);
573 		printf("\n***** PLEASE RERUN FSCK *****\n");
574 	}
575 	if (chkdoreload(mntp, pwarn) != 0) {
576 		if (!fsmodified)
577 			return (0);
578 		if (!preen)
579 			printf("\n***** REBOOT NOW *****\n");
580 		sync();
581 		return (4);
582 	}
583 	return (rerun ? ERERUN : 0);
584 }
585 
586 /*
587  * If we are to do a background check:
588  *	Get the mount point information of the file system
589  *	If already clean, return -1
590  *	Check that kernel supports background fsck
591  *	Find or create the snapshot directory
592  *	Create the snapshot file
593  *	Open snapshot
594  *	If anything fails print reason and return 0 which exits
595  */
596 static int
597 setup_bkgrdchk(struct statfs *mntp, int sbreadfailed, char **filesys)
598 {
599 	struct stat snapdir;
600 	struct group *grp;
601 	struct iovec *iov;
602 	char errmsg[255];
603 	int iovlen;
604 	size_t size;
605 
606 	/* Get the mount point information of the file system */
607 	if (mntp == NULL) {
608 		pwarn("NOT MOUNTED, CANNOT RUN IN BACKGROUND\n");
609 		return (0);
610 	}
611 	if ((mntp->f_flags & MNT_RDONLY) != 0) {
612 		pwarn("MOUNTED READ-ONLY, CANNOT RUN IN BACKGROUND\n");
613 		return (0);
614 	}
615 	if ((mntp->f_flags & MNT_SOFTDEP) == 0) {
616 		pwarn("NOT USING SOFT UPDATES, CANNOT RUN IN BACKGROUND\n");
617 		return (0);
618 	}
619 	if (sbreadfailed) {
620 		pwarn("SUPERBLOCK READ FAILED, CANNOT RUN IN BACKGROUND\n");
621 		return (0);
622 	}
623 	if ((sblock.fs_flags & FS_NEEDSFSCK) != 0) {
624 		pwarn("FULL FSCK NEEDED, CANNOT RUN IN BACKGROUND\n");
625 		return (0);
626 	}
627 	if (skipclean && ckclean &&
628 	   (sblock.fs_flags & (FS_UNCLEAN|FS_NEEDSFSCK)) == 0) {
629 		/*
630 		 * file system is clean;
631 		 * skip snapshot and report it clean
632 		 */
633 		pwarn("FILE SYSTEM CLEAN; SKIPPING CHECKS\n");
634 		return (-1);
635 	}
636 	/* Check that kernel supports background fsck */
637 	size = MIBSIZE;
638 	if (sysctlnametomib("vfs.ffs.adjrefcnt", adjrefcnt, &size) < 0||
639 	    sysctlnametomib("vfs.ffs.adjblkcnt", adjblkcnt, &size) < 0||
640 	    sysctlnametomib("vfs.ffs.setsize", setsize, &size) < 0 ||
641 	    sysctlnametomib("vfs.ffs.freefiles", freefiles, &size) < 0||
642 	    sysctlnametomib("vfs.ffs.freedirs", freedirs, &size) < 0 ||
643 	    sysctlnametomib("vfs.ffs.freeblks", freeblks, &size) < 0) {
644 		pwarn("KERNEL LACKS BACKGROUND FSCK SUPPORT\n");
645 		return (0);
646 	}
647 	/*
648 	 * When kernel lacks runtime bgfsck superblock summary
649 	 * adjustment functionality, it does not mean we can not
650 	 * continue, as old kernels will recompute the summary at
651 	 * mount time. However, it will be an unexpected softupdates
652 	 * inconsistency if it turns out that the summary is still
653 	 * incorrect. Set a flag so subsequent operation can know this.
654 	 */
655 	bkgrdsumadj = 1;
656 	if (sysctlnametomib("vfs.ffs.adjndir", adjndir, &size) < 0 ||
657 	   sysctlnametomib("vfs.ffs.adjnbfree", adjnbfree, &size) < 0 ||
658 	   sysctlnametomib("vfs.ffs.adjnifree", adjnifree, &size) < 0 ||
659 	   sysctlnametomib("vfs.ffs.adjnffree", adjnffree, &size) < 0 ||
660 	   sysctlnametomib("vfs.ffs.adjnumclusters", adjnumclusters,
661 	   &size) < 0) {
662 		bkgrdsumadj = 0;
663 		pwarn("KERNEL LACKS RUNTIME SUPERBLOCK SUMMARY ADJUSTMENT "
664 		    "SUPPORT\n");
665 	}
666 	/* Find or create the snapshot directory */
667 	snprintf(snapname, sizeof snapname, "%s/.snap",
668 	    mntp->f_mntonname);
669 	if (stat(snapname, &snapdir) < 0) {
670 		if (errno != ENOENT) {
671 			pwarn("CANNOT FIND SNAPSHOT DIRECTORY %s: %s, CANNOT "
672 			    "RUN IN BACKGROUND\n", snapname, strerror(errno));
673 			return (0);
674 		}
675 		if ((grp = getgrnam("operator")) == NULL ||
676 			   mkdir(snapname, 0770) < 0 ||
677 			   chown(snapname, -1, grp->gr_gid) < 0 ||
678 			   chmod(snapname, 0770) < 0) {
679 			pwarn("CANNOT CREATE SNAPSHOT DIRECTORY %s: %s, "
680 			    "CANNOT RUN IN BACKGROUND\n", snapname,
681 			    strerror(errno));
682 			return (0);
683 		}
684 	} else if (!S_ISDIR(snapdir.st_mode)) {
685 		pwarn("%s IS NOT A DIRECTORY, CANNOT RUN IN BACKGROUND\n",
686 		    snapname);
687 		return (0);
688 	}
689 	/* Create the snapshot file */
690 	iov = NULL;
691 	iovlen = 0;
692 	errmsg[0] = '\0';
693 	snprintf(snapname, sizeof snapname, "%s/.snap/fsck_snapshot",
694 	    mntp->f_mntonname);
695 	build_iovec(&iov, &iovlen, "fstype", "ffs", 4);
696 	build_iovec(&iov, &iovlen, "from", snapname, (size_t)-1);
697 	build_iovec(&iov, &iovlen, "fspath", mntp->f_mntonname, (size_t)-1);
698 	build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
699 	build_iovec(&iov, &iovlen, "update", NULL, 0);
700 	build_iovec(&iov, &iovlen, "snapshot", NULL, 0);
701 	/* Create snapshot, removing old snapshot if it exists */
702 	while (nmount(iov, iovlen, mntp->f_flags) < 0) {
703 		if (errno == EEXIST && unlink(snapname) == 0)
704 			continue;
705 		pwarn("CANNOT CREATE SNAPSHOT %s: %s %s\n", snapname,
706 		    strerror(errno), errmsg);
707 		return (0);
708 	}
709 	/* Open snapshot */
710 	if (openfilesys(snapname) == 0) {
711 		unlink(snapname);
712 		pwarn("CANNOT OPEN SNAPSHOT %s: %s, CANNOT RUN IN "
713 		    "BACKGROUND\n", snapname, strerror(errno));
714 		return (0);
715 	}
716 	free(sblock.fs_csp);
717 	free(sblock.fs_si);
718 	if (readsb() == 0) {
719 		pwarn("CANNOT READ SNAPSHOT SUPERBLOCK\n");
720 		return (0);
721 	}
722 	*filesys = snapname;
723 	cmd.version = FFS_CMD_VERSION;
724 	cmd.handle = fsreadfd;
725 	return (1);
726 }
727 
728 static void
729 usage(void)
730 {
731 	(void) fprintf(stderr,
732 "usage: %s [-BCdEFfnpRrSyZ] [-b block] [-c level] [-m mode] filesystem ...\n",
733 	    getprogname());
734 	exit(1);
735 }
736 
737 void
738 infohandler(int sig __unused)
739 {
740 	got_siginfo = 1;
741 }
742 
743 void
744 alarmhandler(int sig __unused)
745 {
746 	got_sigalarm = 1;
747 }
748