xref: /csrg-svn/sbin/fsck/setup.c (revision 34140)
122054Sdist /*
222054Sdist  * Copyright (c) 1980 Regents of the University of California.
322054Sdist  * All rights reserved.  The Berkeley software License Agreement
422054Sdist  * specifies the terms and conditions for redistribution.
522054Sdist  */
622054Sdist 
716268Smckusick #ifndef lint
8*34140Smckusick static char sccsid[] = "@(#)setup.c	5.17 (Berkeley) 05/01/88";
922054Sdist #endif not lint
1016268Smckusick 
1130399Smckusick #define DKTYPENAMES
1216268Smckusick #include <sys/param.h>
1316268Smckusick #include <sys/inode.h>
1416268Smckusick #include <sys/fs.h>
1516268Smckusick #include <sys/stat.h>
1630399Smckusick #include <sys/ioctl.h>
1730399Smckusick #include <sys/disklabel.h>
1830399Smckusick #include <sys/file.h>
19*34140Smckusick #include <machine/endian.h>
2030399Smckusick #include <ctype.h>
2116268Smckusick #include "fsck.h"
2216268Smckusick 
23*34140Smckusick BUFAREA asblk;
24*34140Smckusick #define altsblock asblk.b_un.b_fs
2530399Smckusick #define POWEROF2(num)	(((num) & ((num) - 1)) == 0)
2630399Smckusick 
2716268Smckusick char	*calloc();
2830399Smckusick char	*index();
2916268Smckusick 
3016268Smckusick setup(dev)
3116268Smckusick 	char *dev;
3216268Smckusick {
3316268Smckusick 	dev_t rootdev;
3433979Smckusick 	long cg, ncg, size, asked, i, j;
3530859Skarels 	struct disklabel *getdisklabel(), *lp;
3616268Smckusick 	struct stat statb;
3730399Smckusick 	struct fs proto;
3816268Smckusick 
3930859Skarels 	havesb = 0;
4016268Smckusick 	if (stat("/", &statb) < 0)
4116268Smckusick 		errexit("Can't stat root\n");
4216268Smckusick 	rootdev = statb.st_dev;
4316268Smckusick 	if (stat(dev, &statb) < 0) {
4430565Skarels 		perror(dev);
4517931Smckusick 		printf("Can't stat %s\n", dev);
4616268Smckusick 		return (0);
4716268Smckusick 	}
4816268Smckusick 	rawflg = 0;
4916268Smckusick 	if ((statb.st_mode & S_IFMT) == S_IFBLK)
5016268Smckusick 		;
5116268Smckusick 	else if ((statb.st_mode & S_IFMT) == S_IFCHR)
5216268Smckusick 		rawflg++;
5316268Smckusick 	else {
5416268Smckusick 		if (reply("file is not a block or character device; OK") == 0)
5516268Smckusick 			return (0);
5616268Smckusick 	}
5716268Smckusick 	if (rootdev == statb.st_rdev)
5816268Smckusick 		hotroot++;
5930399Smckusick 	if ((dfile.rfdes = open(dev, O_RDONLY)) < 0) {
6030565Skarels 		perror(dev);
6117931Smckusick 		printf("Can't open %s\n", dev);
6216268Smckusick 		return (0);
6316268Smckusick 	}
6416268Smckusick 	if (preen == 0)
6516268Smckusick 		printf("** %s", dev);
6630399Smckusick 	if (nflag || (dfile.wfdes = open(dev, O_WRONLY)) < 0) {
6716268Smckusick 		dfile.wfdes = -1;
6816268Smckusick 		if (preen)
6916268Smckusick 			pfatal("NO WRITE ACCESS");
7016268Smckusick 		printf(" (NO WRITE)");
7116268Smckusick 	}
7216268Smckusick 	if (preen == 0)
7316268Smckusick 		printf("\n");
7416268Smckusick 	dfile.mod = 0;
7516268Smckusick 	lfdir = 0;
7616268Smckusick 	initbarea(&sblk);
7716268Smckusick 	initbarea(&fileblk);
7816268Smckusick 	initbarea(&inoblk);
7916268Smckusick 	initbarea(&cgblk);
80*34140Smckusick 	initbarea(&asblk);
8130859Skarels 	if (lp = getdisklabel((char *)NULL, dfile.rfdes))
8230859Skarels 		dev_bsize = secsize = lp->d_secsize;
83*34140Smckusick 	else
84*34140Smckusick 		dev_bsize = secsize = DEV_BSIZE;
8516268Smckusick 	/*
8630399Smckusick 	 * Read in the superblock, looking for alternates if necessary
8716268Smckusick 	 */
8830399Smckusick 	if (readsb(1) == 0) {
8930859Skarels 		if (bflag || preen || calcsb(dev, dfile.rfdes, &proto) == 0)
9030399Smckusick 			return(0);
9130399Smckusick 		if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
9230399Smckusick 			return (0);
9330399Smckusick 		for (cg = 0; cg < proto.fs_ncg; cg++) {
9430399Smckusick 			bflag = fsbtodb(&proto, cgsblock(&proto, cg));
9530399Smckusick 			if (readsb(0) != 0)
9630399Smckusick 				break;
9730399Smckusick 		}
9830399Smckusick 		if (cg >= proto.fs_ncg) {
9930399Smckusick 			printf("%s %s\n%s %s\n%s %s\n",
10030399Smckusick 				"SEARCH FOR ALTERNATE SUPER-BLOCK",
10130399Smckusick 				"FAILED. YOU MUST USE THE",
10230399Smckusick 				"-b OPTION TO FSCK TO SPECIFY THE",
10330399Smckusick 				"LOCATION OF AN ALTERNATE",
10430399Smckusick 				"SUPER-BLOCK TO SUPPLY NEEDED",
10530399Smckusick 				"INFORMATION; SEE fsck(8).");
10630399Smckusick 			return(0);
10730399Smckusick 		}
10830399Smckusick 		pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
10930399Smckusick 	}
11030399Smckusick 	fmax = sblock.fs_size;
11130399Smckusick 	imax = sblock.fs_ncg * sblock.fs_ipg;
11216268Smckusick 	/*
11328213Smckusick 	 * Check and potentially fix certain fields in the super block.
11428213Smckusick 	 */
11528213Smckusick 	if (sblock.fs_optim != FS_OPTTIME && sblock.fs_optim != FS_OPTSPACE) {
11628213Smckusick 		pfatal("UNDEFINED OPTIMIZATION IN SUPERBLOCK");
11728213Smckusick 		if (reply("SET TO DEFAULT") == 1) {
11828213Smckusick 			sblock.fs_optim = FS_OPTTIME;
11928213Smckusick 			sbdirty();
12028213Smckusick 		}
12128213Smckusick 	}
12228213Smckusick 	if ((sblock.fs_minfree < 0 || sblock.fs_minfree > 99)) {
12328213Smckusick 		pfatal("IMPOSSIBLE MINFREE=%d IN SUPERBLOCK",
12428213Smckusick 			sblock.fs_minfree);
12528213Smckusick 		if (reply("SET TO DEFAULT") == 1) {
12628213Smckusick 			sblock.fs_minfree = 10;
12728213Smckusick 			sbdirty();
12828213Smckusick 		}
12928213Smckusick 	}
13030400Smckusick 	if (sblock.fs_interleave < 1) {
13130597Smckusick 		pwarn("IMPOSSIBLE INTERLEAVE=%d IN SUPERBLOCK",
13230400Smckusick 			sblock.fs_interleave);
13330586Smckusick 		sblock.fs_interleave = 1;
13430597Smckusick 		if (preen)
13530597Smckusick 			printf(" (FIXED)\n");
136*34140Smckusick 		if (preen || reply("SET TO DEFAULT") == 1) {
13730400Smckusick 			sbdirty();
138*34140Smckusick 			dirty(&asblk);
139*34140Smckusick 		}
14030400Smckusick 	}
14130400Smckusick 	if (sblock.fs_npsect < sblock.fs_nsect) {
14230597Smckusick 		pwarn("IMPOSSIBLE NPSECT=%d IN SUPERBLOCK",
14330400Smckusick 			sblock.fs_npsect);
14430586Smckusick 		sblock.fs_npsect = sblock.fs_nsect;
14530597Smckusick 		if (preen)
14630597Smckusick 			printf(" (FIXED)\n");
147*34140Smckusick 		if (preen || reply("SET TO DEFAULT") == 1) {
14830400Smckusick 			sbdirty();
149*34140Smckusick 			dirty(&asblk);
150*34140Smckusick 		}
15130400Smckusick 	}
152*34140Smckusick 	if (sblock.fs_postblformat == FS_42POSTBLFMT) {
153*34140Smckusick 		pwarn("OLD FILE SYSTEM FORMAT\n");
154*34140Smckusick 		if (!preen && reply("CONVERT TO NEW FILE SYSTEM FORMAT") == 1) {
155*34140Smckusick 			cvtflag++;
156*34140Smckusick 			sblock.fs_postblformat = FS_DYNAMICPOSTBLFMT;
157*34140Smckusick 			sblock.fs_nrpos = 8;
158*34140Smckusick 			sblock.fs_postbloff =
159*34140Smckusick 			    (char *)(&sblock.fs_opostbl[0][0]) -
160*34140Smckusick 			    (char *)(&sblock.fs_link);
161*34140Smckusick 			sblock.fs_rotbloff = &sblock.fs_space[0] -
162*34140Smckusick 			    (u_char *)(&sblock.fs_link);
163*34140Smckusick 			/*
164*34140Smckusick 			 * Planning now for future expansion.
165*34140Smckusick 			 */
166*34140Smckusick #			if (BYTE_ORDER == BIG_ENDIAN)
167*34140Smckusick 				sblock.fs_qbmask.val[0] = 0;
168*34140Smckusick 				sblock.fs_qbmask.val[1] = ~sblock.fs_bmask;
169*34140Smckusick 				sblock.fs_qfmask.val[0] = 0;
170*34140Smckusick 				sblock.fs_qfmask.val[1] = ~sblock.fs_fmask;
171*34140Smckusick #			endif /* BIG_ENDIAN */
172*34140Smckusick #			if (BYTE_ORDER == LITTLE_ENDIAN)
173*34140Smckusick 				sblock.fs_qbmask.val[0] = ~sblock.fs_bmask;
174*34140Smckusick 				sblock.fs_qbmask.val[1] = 0;
175*34140Smckusick 				sblock.fs_qfmask.val[0] = ~sblock.fs_fmask;
176*34140Smckusick 				sblock.fs_qfmask.val[1] = 0;
177*34140Smckusick #			endif /* LITTLE_ENDIAN */
178*34140Smckusick 			sbdirty();
179*34140Smckusick 			dirty(&asblk);
180*34140Smckusick 		}
181*34140Smckusick 	} else if (cvtflag) {
182*34140Smckusick 		/*
183*34140Smckusick 		 * Requested to convert from new format to old format
184*34140Smckusick 		 */
185*34140Smckusick 		if (sblock.fs_nrpos != 8 || sblock.fs_ipg > 2048 ||
186*34140Smckusick 		    sblock.fs_cpg > 32) {
187*34140Smckusick 			printf("PARAMETERS OF CURRENT FILE SYSTEM DO NOT\n\t");
188*34140Smckusick 			errexit("ALLOW CONVERSION TO OLD FILE SYSTEM FORMAT\n");
189*34140Smckusick 		}
190*34140Smckusick 		pwarn("CONVERTING TO OLD FILE SYSTEM FORMAT\n");
191*34140Smckusick 		sblock.fs_postblformat = FS_42POSTBLFMT;
192*34140Smckusick 		sbdirty();
193*34140Smckusick 		dirty(&asblk);
194*34140Smckusick 	}
195*34140Smckusick 	if (asblk.b_dirty) {
196*34140Smckusick 		bcopy((char *)&sblock, (char *)&altsblock, sblock.fs_sbsize);
197*34140Smckusick 		flush(&dfile, &asblk);
198*34140Smckusick 	}
19928213Smckusick 	/*
20016268Smckusick 	 * read in the summary info.
20116268Smckusick 	 */
20233979Smckusick 	asked = 0;
20316268Smckusick 	for (i = 0, j = 0; i < sblock.fs_cssize; i += sblock.fs_bsize, j++) {
20416268Smckusick 		size = sblock.fs_cssize - i < sblock.fs_bsize ?
20516268Smckusick 		    sblock.fs_cssize - i : sblock.fs_bsize;
20616268Smckusick 		sblock.fs_csp[j] = (struct csum *)calloc(1, (unsigned)size);
20716268Smckusick 		if (bread(&dfile, (char *)sblock.fs_csp[j],
20816268Smckusick 		    fsbtodb(&sblock, sblock.fs_csaddr + j * sblock.fs_frag),
20933979Smckusick 		    size) != 0 && !asked) {
21033979Smckusick 			pfatal("BAD SUMMARY INFORMATION");
21133979Smckusick 			if (reply("CONTINUE") == 0)
21233979Smckusick 				errexit("");
21333979Smckusick 			asked++;
21433979Smckusick 		}
21516268Smckusick 	}
21616268Smckusick 	/*
21716268Smckusick 	 * allocate and initialize the necessary maps
21816268Smckusick 	 */
21916268Smckusick 	bmapsz = roundup(howmany(fmax, NBBY), sizeof(short));
22016268Smckusick 	blockmap = calloc((unsigned)bmapsz, sizeof (char));
22116268Smckusick 	if (blockmap == NULL) {
22216268Smckusick 		printf("cannot alloc %d bytes for blockmap\n", bmapsz);
22316268Smckusick 		goto badsb;
22416268Smckusick 	}
22516268Smckusick 	statemap = calloc((unsigned)(imax + 1), sizeof(char));
22616268Smckusick 	if (statemap == NULL) {
22716268Smckusick 		printf("cannot alloc %d bytes for statemap\n", imax + 1);
22816268Smckusick 		goto badsb;
22916268Smckusick 	}
23016268Smckusick 	lncntp = (short *)calloc((unsigned)(imax + 1), sizeof(short));
23116268Smckusick 	if (lncntp == NULL) {
23216268Smckusick 		printf("cannot alloc %d bytes for lncntp\n",
23316268Smckusick 		    (imax + 1) * sizeof(short));
23416268Smckusick 		goto badsb;
23516268Smckusick 	}
23616268Smckusick 
23716268Smckusick 	return (1);
23816268Smckusick 
23916268Smckusick badsb:
24016268Smckusick 	ckfini();
24116268Smckusick 	return (0);
24230399Smckusick }
24330399Smckusick 
24430399Smckusick /*
24530399Smckusick  * Read in the super block and its summary info.
24630399Smckusick  */
24730399Smckusick readsb(listerr)
24830399Smckusick 	int listerr;
24930399Smckusick {
25030859Skarels 	off_t sboff;
25130859Skarels 	daddr_t super = bflag ? bflag : SBOFF / dev_bsize;
25230399Smckusick 
25330399Smckusick 	if (bread(&dfile, (char *)&sblock, super, (long)SBSIZE) != 0)
25430399Smckusick 		return (0);
25530399Smckusick 	sblk.b_bno = super;
25630399Smckusick 	sblk.b_size = SBSIZE;
25730399Smckusick 	/*
25830399Smckusick 	 * run a few consistency checks of the super block
25930399Smckusick 	 */
26030399Smckusick 	if (sblock.fs_magic != FS_MAGIC)
26130399Smckusick 		{ badsb(listerr, "MAGIC NUMBER WRONG"); return (0); }
26230399Smckusick 	if (sblock.fs_ncg < 1)
26330399Smckusick 		{ badsb(listerr, "NCG OUT OF RANGE"); return (0); }
264*34140Smckusick 	if (sblock.fs_cpg < 1)
26530399Smckusick 		{ badsb(listerr, "CPG OUT OF RANGE"); return (0); }
26630399Smckusick 	if (sblock.fs_ncg * sblock.fs_cpg < sblock.fs_ncyl ||
26730399Smckusick 	    (sblock.fs_ncg - 1) * sblock.fs_cpg >= sblock.fs_ncyl)
26830399Smckusick 		{ badsb(listerr, "NCYL LESS THAN NCG*CPG"); return (0); }
26930399Smckusick 	if (sblock.fs_sbsize > SBSIZE)
27030399Smckusick 		{ badsb(listerr, "SIZE PREPOSTEROUSLY LARGE"); return (0); }
27130399Smckusick 	/*
27230859Skarels 	 * Compute block size that the filesystem is based on,
27330859Skarels 	 * according to fsbtodb, and adjust superblock block number
27430859Skarels 	 * so we can tell if this is an alternate later.
27530859Skarels 	 */
27630859Skarels 	super *= dev_bsize;
27730859Skarels 	dev_bsize = sblock.fs_fsize / fsbtodb(&sblock, 1);
27830859Skarels 	sblk.b_bno = super / dev_bsize;
27930859Skarels 	/*
28030399Smckusick 	 * Set all possible fields that could differ, then do check
28130399Smckusick 	 * of whole super block against an alternate super block.
28230399Smckusick 	 * When an alternate super-block is specified this check is skipped.
28330399Smckusick 	 */
284*34140Smckusick 	getblk(&asblk, cgsblock(&sblock, sblock.fs_ncg - 1), sblock.fs_sbsize);
285*34140Smckusick 	if (asblk.b_errs != NULL)
286*34140Smckusick 		return (0);
28730859Skarels 	if (bflag) {
28830859Skarels 		havesb = 1;
28930399Smckusick 		return (1);
29030859Skarels 	}
29130399Smckusick 	altsblock.fs_link = sblock.fs_link;
29230399Smckusick 	altsblock.fs_rlink = sblock.fs_rlink;
29330399Smckusick 	altsblock.fs_time = sblock.fs_time;
29430399Smckusick 	altsblock.fs_cstotal = sblock.fs_cstotal;
29530399Smckusick 	altsblock.fs_cgrotor = sblock.fs_cgrotor;
29630399Smckusick 	altsblock.fs_fmod = sblock.fs_fmod;
29730399Smckusick 	altsblock.fs_clean = sblock.fs_clean;
29830399Smckusick 	altsblock.fs_ronly = sblock.fs_ronly;
29930399Smckusick 	altsblock.fs_flags = sblock.fs_flags;
30030399Smckusick 	altsblock.fs_maxcontig = sblock.fs_maxcontig;
30130399Smckusick 	altsblock.fs_minfree = sblock.fs_minfree;
30230399Smckusick 	altsblock.fs_optim = sblock.fs_optim;
30330399Smckusick 	altsblock.fs_rotdelay = sblock.fs_rotdelay;
30430399Smckusick 	altsblock.fs_maxbpg = sblock.fs_maxbpg;
30530399Smckusick 	bcopy((char *)sblock.fs_csp, (char *)altsblock.fs_csp,
30630399Smckusick 		sizeof sblock.fs_csp);
30730399Smckusick 	bcopy((char *)sblock.fs_fsmnt, (char *)altsblock.fs_fsmnt,
30830399Smckusick 		sizeof sblock.fs_fsmnt);
30930565Skarels 	bcopy((char *)sblock.fs_sparecon, (char *)altsblock.fs_sparecon,
31030565Skarels 		sizeof sblock.fs_sparecon);
311*34140Smckusick 	/*
312*34140Smckusick 	 * The following should not have to be copied.
313*34140Smckusick 	 */
314*34140Smckusick 	altsblock.fs_fsbtodb = sblock.fs_fsbtodb;
315*34140Smckusick 	altsblock.fs_interleave = sblock.fs_interleave;
316*34140Smckusick 	altsblock.fs_npsect = sblock.fs_npsect;
317*34140Smckusick 	altsblock.fs_nrpos = sblock.fs_nrpos;
31830565Skarels 	if (bcmp((char *)&sblock, (char *)&altsblock, (int)sblock.fs_sbsize)) {
31930565Skarels 		badsb(listerr,
32030565Skarels 		"VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE");
32130565Skarels 		return (0);
32230565Skarels 	}
32330859Skarels 	havesb = 1;
32430399Smckusick 	return (1);
32516268Smckusick }
32616268Smckusick 
32730399Smckusick badsb(listerr, s)
32830399Smckusick 	int listerr;
32916268Smckusick 	char *s;
33016268Smckusick {
33116268Smckusick 
33230399Smckusick 	if (!listerr)
33330399Smckusick 		return;
33416268Smckusick 	if (preen)
33516268Smckusick 		printf("%s: ", devname);
33630399Smckusick 	pfatal("BAD SUPER BLOCK: %s\n", s);
33716268Smckusick }
33830399Smckusick 
33930399Smckusick /*
34030399Smckusick  * Calculate a prototype superblock based on information in the disk label.
34130399Smckusick  * When done the cgsblock macro can be calculated and the fs_ncg field
34230399Smckusick  * can be used. Do NOT attempt to use other macros without verifying that
34330399Smckusick  * their needed information is available!
34430399Smckusick  */
34530399Smckusick calcsb(dev, devfd, fs)
34630399Smckusick 	char *dev;
34730399Smckusick 	int devfd;
34830399Smckusick 	register struct fs *fs;
34930399Smckusick {
35030399Smckusick 	register struct disklabel *lp;
35130399Smckusick 	register struct partition *pp;
35230399Smckusick 	register char *cp;
35330399Smckusick 	int i;
35433084Sbostic 	struct disklabel *getdisklabel();
35530399Smckusick 
35630399Smckusick 	cp = index(dev, '\0') - 1;
35730399Smckusick 	if (cp == (char *)-1 || (*cp < 'a' || *cp > 'h') && !isdigit(*cp)) {
35830399Smckusick 		pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
35930399Smckusick 		return (0);
36030399Smckusick 	}
36130399Smckusick 	lp = getdisklabel(dev, devfd);
36230399Smckusick 	if (isdigit(*cp))
36330399Smckusick 		pp = &lp->d_partitions[0];
36430399Smckusick 	else
36530399Smckusick 		pp = &lp->d_partitions[*cp - 'a'];
36630399Smckusick 	if (pp->p_fstype != FS_BSDFFS) {
36730859Skarels 		pfatal("%s: NOT LABELED AS A BSD FILE SYSTEM (%s)\n",
36830399Smckusick 			dev, pp->p_fstype < FSMAXTYPES ?
36930399Smckusick 			fstypenames[pp->p_fstype] : "unknown");
37030399Smckusick 		return (0);
37130399Smckusick 	}
37230399Smckusick 	bzero(fs, sizeof(struct fs));
37330399Smckusick 	fs->fs_fsize = pp->p_fsize;
37430399Smckusick 	fs->fs_frag = pp->p_frag;
37530399Smckusick 	fs->fs_cpg = pp->p_cpg;
37630399Smckusick 	fs->fs_size = pp->p_size;
37730399Smckusick 	fs->fs_ntrak = lp->d_ntracks;
37830399Smckusick 	fs->fs_nsect = lp->d_nsectors;
37930399Smckusick 	fs->fs_spc = lp->d_secpercyl;
38030399Smckusick 	fs->fs_nspf = fs->fs_fsize / lp->d_secsize;
38130399Smckusick 	fs->fs_sblkno = roundup(
38230399Smckusick 		howmany(lp->d_bbsize + lp->d_sbsize, fs->fs_fsize),
38330399Smckusick 		fs->fs_frag);
38430399Smckusick 	fs->fs_cgmask = 0xffffffff;
38530399Smckusick 	for (i = fs->fs_ntrak; i > 1; i >>= 1)
38630399Smckusick 		fs->fs_cgmask <<= 1;
38730399Smckusick 	if (!POWEROF2(fs->fs_ntrak))
38830399Smckusick 		fs->fs_cgmask <<= 1;
38930399Smckusick 	fs->fs_cgoffset = roundup(
39030399Smckusick 		howmany(fs->fs_nsect, NSPF(fs)), fs->fs_frag);
39130399Smckusick 	fs->fs_fpg = (fs->fs_cpg * fs->fs_spc) / NSPF(fs);
39230399Smckusick 	fs->fs_ncg = howmany(fs->fs_size / fs->fs_spc, fs->fs_cpg);
39330399Smckusick 	for (fs->fs_fsbtodb = 0, i = NSPF(fs); i > 1; i >>= 1)
39430399Smckusick 		fs->fs_fsbtodb++;
39530859Skarels 	dev_bsize = lp->d_secsize;
39630399Smckusick 	return (1);
39730399Smckusick }
39830399Smckusick 
39930399Smckusick struct disklabel *
40030399Smckusick getdisklabel(s, fd)
40130399Smckusick 	char *s;
40230399Smckusick 	int	fd;
40330399Smckusick {
40430399Smckusick 	static struct disklabel lab;
40530399Smckusick 
40630399Smckusick 	if (ioctl(fd, DIOCGDINFO, (char *)&lab) < 0) {
40730609Skarels 		if (s == NULL)
40830609Skarels 			return ((struct disklabel *)NULL);
40930565Skarels 		pwarn("");
41030399Smckusick 		perror("ioctl (GDINFO)");
41130565Skarels 		errexit("%s: can't read disk label", s);
41230399Smckusick 	}
41330399Smckusick 	return (&lab);
41430399Smckusick }
415