sbin/fsck_ffs/setup.c

   1 /*
   2  * Copyright (c) 1980, 1986, 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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if 0
  31 #ifndef lint
  32 static const char sccsid[] = "@(#)setup.c       8.10 (Berkeley) 5/9/95";
  33 #endif /* not lint */
  34 #endif
  35 #include <sys/cdefs.h>
  36 __FBSDID("$FreeBSD$");
  37
  38 #include <sys/param.h>
  39 #include <sys/stat.h>
  40 #define FSTYPENAMES
  41 #include <sys/disklabel.h>
  42 #include <sys/file.h>
  43 #include <sys/sysctl.h>
  44
  45 #include <ufs/ufs/dinode.h>
  46 #include <ufs/ffs/fs.h>
  47
  48 #include <ctype.h>
  49 #include <err.h>
  50 #include <errno.h>
  51 #include <limits.h>
  52 #include <stdint.h>
  53 #include <string.h>
  54
  55 #include "fsck.h"
  56
  57 struct bufarea asblk;
  58 #define altsblock (*asblk.b_un.b_fs)
  59 #define POWEROF2(num)   (((num) & ((num) - 1)) == 0)
  60
  61 static void badsb(int listerr, const char *s);
  62 static int calcsb(char *dev, int devfd, struct fs *fs);
  63 static struct disklabel *getdisklabel(char *s, int fd);
  64
  65 /*
  66  * Read in a superblock finding an alternate if necessary.
  67  * Return 1 if successful, 0 if unsuccessful, -1 if file system
  68  * is already clean (ckclean and preen mode only).
  69  */
  70 int
  71 setup(char *dev)
  72 {
  73         long cg, asked, i, j;
  74         long bmapsize;
  75         struct stat statb;
  76         struct fs proto;
  77         size_t size;
  78
  79         havesb = 0;
  80         fswritefd = -1;
  81         cursnapshot = 0;
  82         if (stat(dev, &statb) < 0) {
  83                 printf("Can't stat %s: %s\n", dev, strerror(errno));
  84                 if (bkgrdflag) {
  85                         unlink(snapname);
  86                         bkgrdflag = 0;
  87                 }
  88                 return (0);
  89         }
  90         if ((statb.st_mode & S_IFMT) != S_IFCHR &&
  91             (statb.st_mode & S_IFMT) != S_IFBLK) {
  92                 if (bkgrdflag != 0 && (statb.st_flags & SF_SNAPSHOT) == 0) {
  93                         unlink(snapname);
  94                         printf("background fsck lacks a snapshot\n");
  95                         exit(EEXIT);
  96                 }
  97                 if ((statb.st_flags & SF_SNAPSHOT) != 0 && cvtlevel == 0) {
  98                         cursnapshot = statb.st_ino;
  99                 } else {
 100                         if (cvtlevel == 0 ||
 101                             (statb.st_flags & SF_SNAPSHOT) == 0) {
 102                                 if (preen && bkgrdflag) {
 103                                         unlink(snapname);
 104                                         bkgrdflag = 0;
 105                                 }
 106                                 pfatal("%s is not a disk device", dev);
 107                                 if (reply("CONTINUE") == 0) {
 108                                         if (bkgrdflag) {
 109                                                 unlink(snapname);
 110                                                 bkgrdflag = 0;
 111                                         }
 112                                         return (0);
 113                                 }
 114                         } else {
 115                                 if (bkgrdflag) {
 116                                         unlink(snapname);
 117                                         bkgrdflag = 0;
 118                                 }
 119                                 pfatal("cannot convert a snapshot");
 120                                 exit(EEXIT);
 121                         }
 122                 }
 123         }
 124         if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
 125                 if (bkgrdflag) {
 126                         unlink(snapname);
 127                         bkgrdflag = 0;
 128                 }
 129                 printf("Can't open %s: %s\n", dev, strerror(errno));
 130                 return (0);
 131         }
 132         if (bkgrdflag) {
 133                 unlink(snapname);
 134                 size = MIBSIZE;
 135                 if (sysctlnametomib("vfs.ffs.adjrefcnt", adjrefcnt, &size) < 0||
 136                     sysctlnametomib("vfs.ffs.adjblkcnt", adjblkcnt, &size) < 0||
 137                     sysctlnametomib("vfs.ffs.freefiles", freefiles, &size) < 0||
 138                     sysctlnametomib("vfs.ffs.freedirs", freedirs, &size) < 0 ||
 139                     sysctlnametomib("vfs.ffs.freeblks", freeblks, &size) < 0) {
 140                         pfatal("kernel lacks background fsck support\n");
 141                         exit(EEXIT);
 142                 }
 143                 /*
 144                  * When kernel is lack of runtime bgfsck superblock summary
 145                  * adjustment functionality, it does not mean we can not
 146                  * continue, as old kernels will recompute the summary at
 147                  * mount time.  However, it will be an unexpected softupdates
 148                  * inconsistency if it turns out that the summary is still
 149                  * incorrect.  Set a flag so subsequent operation can know
 150                  * this.
 151                  */
 152                 bkgrdsumadj = 1;
 153                 if (sysctlnametomib("vfs.ffs.adjndir", adjndir, &size) < 0 ||
 154                     sysctlnametomib("vfs.ffs.adjnbfree", adjnbfree, &size) < 0 ||
 155                     sysctlnametomib("vfs.ffs.adjnifree", adjnifree, &size) < 0 ||
 156                     sysctlnametomib("vfs.ffs.adjnffree", adjnffree, &size) < 0 ||
 157                     sysctlnametomib("vfs.ffs.adjnumclusters", adjnumclusters, &size) < 0) {
 158                         bkgrdsumadj = 0;
 159                         pwarn("kernel lacks runtime superblock summary adjustment support");
 160                 }
 161                 cmd.version = FFS_CMD_VERSION;
 162                 cmd.handle = fsreadfd;
 163                 fswritefd = -1;
 164         }
 165         if (preen == 0)
 166                 printf("** %s", dev);
 167         if (bkgrdflag == 0 &&
 168             (nflag || (fswritefd = open(dev, O_WRONLY)) < 0)) {
 169                 fswritefd = -1;
 170                 if (preen)
 171                         pfatal("NO WRITE ACCESS");
 172                 printf(" (NO WRITE)");
 173         }
 174         if (preen == 0)
 175                 printf("\n");
 176         /*
 177          * Read in the superblock, looking for alternates if necessary
 178          */
 179         if (readsb(1) == 0) {
 180                 skipclean = 0;
 181                 if (bflag || preen || calcsb(dev, fsreadfd, &proto) == 0)
 182                         return(0);
 183                 if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
 184                         return (0);
 185                 for (cg = 0; cg < proto.fs_ncg; cg++) {
 186                         bflag = fsbtodb(&proto, cgsblock(&proto, cg));
 187                         if (readsb(0) != 0)
 188                                 break;
 189                 }
 190                 if (cg >= proto.fs_ncg) {
 191                         printf("%s %s\n%s %s\n%s %s\n",
 192                                 "SEARCH FOR ALTERNATE SUPER-BLOCK",
 193                                 "FAILED. YOU MUST USE THE",
 194                                 "-b OPTION TO FSCK TO SPECIFY THE",
 195                                 "LOCATION OF AN ALTERNATE",
 196                                 "SUPER-BLOCK TO SUPPLY NEEDED",
 197                                 "INFORMATION; SEE fsck(8).");
 198                         bflag = 0;
 199                         return(0);
 200                 }
 201                 pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
 202                 bflag = 0;
 203         }
 204         if (skipclean && ckclean && sblock.fs_clean) {
 205                 pwarn("FILE SYSTEM CLEAN; SKIPPING CHECKS\n");
 206                 return (-1);
 207         }
 208         maxfsblock = sblock.fs_size;
 209         maxino = sblock.fs_ncg * sblock.fs_ipg;
 210         /*
 211          * Check and potentially fix certain fields in the super block.
 212          */
 213         if (sblock.fs_optim != FS_OPTTIME && sblock.fs_optim != FS_OPTSPACE) {
 214                 pfatal("UNDEFINED OPTIMIZATION IN SUPERBLOCK");
 215                 if (reply("SET TO DEFAULT") == 1) {
 216                         sblock.fs_optim = FS_OPTTIME;
 217                         sbdirty();
 218                 }
 219         }
 220         if ((sblock.fs_minfree < 0 || sblock.fs_minfree > 99)) {
 221                 pfatal("IMPOSSIBLE MINFREE=%d IN SUPERBLOCK",
 222                         sblock.fs_minfree);
 223                 if (reply("SET TO DEFAULT") == 1) {
 224                         sblock.fs_minfree = 10;
 225                         sbdirty();
 226                 }
 227         }
 228         if (sblock.fs_magic == FS_UFS1_MAGIC &&
 229             sblock.fs_old_inodefmt < FS_44INODEFMT) {
 230                 pwarn("Format of file system is too old.\n");
 231                 pwarn("Must update to modern format using a version of fsck\n");
 232                 pfatal("from before 2002 with the command ``fsck -c 2''\n");
 233                 exit(EEXIT);
 234         }
 235         if (asblk.b_dirty && !bflag) {
 236                 memmove(&altsblock, &sblock, (size_t)sblock.fs_sbsize);
 237                 flush(fswritefd, &asblk);
 238         }
 239         /*
 240          * read in the summary info.
 241          */
 242         asked = 0;
 243         sblock.fs_csp = calloc(1, sblock.fs_cssize);
 244         if (sblock.fs_csp == NULL) {
 245                 printf("cannot alloc %u bytes for cg summary info\n",
 246                     (unsigned)sblock.fs_cssize);
 247                 goto badsb;
 248         }
 249         for (i = 0, j = 0; i < sblock.fs_cssize; i += sblock.fs_bsize, j++) {
 250                 size = sblock.fs_cssize - i < sblock.fs_bsize ?
 251                     sblock.fs_cssize - i : sblock.fs_bsize;
 252                 if (blread(fsreadfd, (char *)sblock.fs_csp + i,
 253                     fsbtodb(&sblock, sblock.fs_csaddr + j * sblock.fs_frag),
 254                     size) != 0 && !asked) {
 255                         pfatal("BAD SUMMARY INFORMATION");
 256                         if (reply("CONTINUE") == 0) {
 257                                 ckfini(0);
 258                                 exit(EEXIT);
 259                         }
 260                         asked++;
 261                 }
 262         }
 263         /*
 264          * allocate and initialize the necessary maps
 265          */
 266         bmapsize = roundup(howmany(maxfsblock, CHAR_BIT), sizeof(short));
 267         blockmap = calloc((unsigned)bmapsize, sizeof (char));
 268         if (blockmap == NULL) {
 269                 printf("cannot alloc %u bytes for blockmap\n",
 270                     (unsigned)bmapsize);
 271                 goto badsb;
 272         }
 273         inostathead = calloc((unsigned)(sblock.fs_ncg),
 274             sizeof(struct inostatlist));
 275         if (inostathead == NULL) {
 276                 printf("cannot alloc %u bytes for inostathead\n",
 277                     (unsigned)(sizeof(struct inostatlist) * (sblock.fs_ncg)));
 278                 goto badsb;
 279         }
 280         numdirs = MAX(sblock.fs_cstotal.cs_ndir, 128);
 281         dirhash = numdirs;
 282         inplast = 0;
 283         listmax = numdirs + 10;
 284         inpsort = (struct inoinfo **)calloc((unsigned)listmax,
 285             sizeof(struct inoinfo *));
 286         inphead = (struct inoinfo **)calloc((unsigned)numdirs,
 287             sizeof(struct inoinfo *));
 288         if (inpsort == NULL || inphead == NULL) {
 289                 printf("cannot alloc %ju bytes for inphead\n",
 290                     (uintmax_t)numdirs * sizeof(struct inoinfo *));
 291                 goto badsb;
 292         }
 293         bufinit();
 294         if (sblock.fs_flags & FS_DOSOFTDEP)
 295                 usedsoftdep = 1;
 296         else
 297                 usedsoftdep = 0;
 298         return (1);
 299
 300 badsb:
 301         ckfini(0);
 302         return (0);
 303 }
 304
 305 /*
 306  * Possible superblock locations ordered from most to least likely.
 307  */
 308 static int sblock_try[] = SBLOCKSEARCH;
 309
 310 #define BAD_MAGIC_MSG \
 311 "The previous newfs operation on this volume did not complete.\n" \
 312 "You must complete newfs before mounting this volume.\n"
 313
 314 /*
 315  * Read in the super block and its summary info.
 316  */
 317 int
 318 readsb(int listerr)
 319 {
 320         ufs2_daddr_t super;
 321         int i;
 322
 323         if (bflag) {
 324                 super = bflag;
 325                 if ((blread(fsreadfd, (char *)&sblock, super, (long)SBLOCKSIZE)))
 326                         return (0);
 327                 if (sblock.fs_magic == FS_BAD_MAGIC) {
 328                         fprintf(stderr, BAD_MAGIC_MSG);
 329                         exit(11);
 330                 }
 331                 if (sblock.fs_magic != FS_UFS1_MAGIC &&
 332                     sblock.fs_magic != FS_UFS2_MAGIC) {
 333                         fprintf(stderr, "%d is not a file system superblock\n",
 334                             bflag);
 335                         return (0);
 336                 }
 337         } else {
 338                 for (i = 0; sblock_try[i] != -1; i++) {
 339                         super = sblock_try[i] / dev_bsize;
 340                         if ((blread(fsreadfd, (char *)&sblock, super,
 341                             (long)SBLOCKSIZE)))
 342                                 return (0);
 343                         if (sblock.fs_magic == FS_BAD_MAGIC) {
 344                                 fprintf(stderr, BAD_MAGIC_MSG);
 345                                 exit(11);
 346                         }
 347                         if ((sblock.fs_magic == FS_UFS1_MAGIC ||
 348                              (sblock.fs_magic == FS_UFS2_MAGIC &&
 349                               sblock.fs_sblockloc == sblock_try[i])) &&
 350                             sblock.fs_ncg >= 1 &&
 351                             sblock.fs_bsize >= MINBSIZE &&
 352                             sblock.fs_bsize >= sizeof(struct fs))
 353                                 break;
 354                 }
 355                 if (sblock_try[i] == -1) {
 356                         fprintf(stderr, "Cannot find file system superblock\n");
 357                         return (0);
 358                 }
 359         }
 360         /*
 361          * Compute block size that the file system is based on,
 362          * according to fsbtodb, and adjust superblock block number
 363          * so we can tell if this is an alternate later.
 364          */
 365         super *= dev_bsize;
 366         dev_bsize = sblock.fs_fsize / fsbtodb(&sblock, 1);
 367         sblk.b_bno = super / dev_bsize;
 368         sblk.b_size = SBLOCKSIZE;
 369         if (bflag)
 370                 goto out;
 371         /*
 372          * Compare all fields that should not differ in alternate super block.
 373          * When an alternate super-block is specified this check is skipped.
 374          */
 375         getblk(&asblk, cgsblock(&sblock, sblock.fs_ncg - 1), sblock.fs_sbsize);
 376         if (asblk.b_errs)
 377                 return (0);
 378         if (altsblock.fs_sblkno != sblock.fs_sblkno ||
 379             altsblock.fs_cblkno != sblock.fs_cblkno ||
 380             altsblock.fs_iblkno != sblock.fs_iblkno ||
 381             altsblock.fs_dblkno != sblock.fs_dblkno ||
 382             altsblock.fs_ncg != sblock.fs_ncg ||
 383             altsblock.fs_bsize != sblock.fs_bsize ||
 384             altsblock.fs_fsize != sblock.fs_fsize ||
 385             altsblock.fs_frag != sblock.fs_frag ||
 386             altsblock.fs_bmask != sblock.fs_bmask ||
 387             altsblock.fs_fmask != sblock.fs_fmask ||
 388             altsblock.fs_bshift != sblock.fs_bshift ||
 389             altsblock.fs_fshift != sblock.fs_fshift ||
 390             altsblock.fs_fragshift != sblock.fs_fragshift ||
 391             altsblock.fs_fsbtodb != sblock.fs_fsbtodb ||
 392             altsblock.fs_sbsize != sblock.fs_sbsize ||
 393             altsblock.fs_nindir != sblock.fs_nindir ||
 394             altsblock.fs_inopb != sblock.fs_inopb ||
 395             altsblock.fs_cssize != sblock.fs_cssize ||
 396             altsblock.fs_ipg != sblock.fs_ipg ||
 397             altsblock.fs_fpg != sblock.fs_fpg ||
 398             altsblock.fs_magic != sblock.fs_magic) {
 399                 badsb(listerr,
 400                 "VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE");
 401                 return (0);
 402         }
 403 out:
 404         /*
 405          * If not yet done, update UFS1 superblock with new wider fields.
 406          */
 407         if (sblock.fs_magic == FS_UFS1_MAGIC &&
 408             sblock.fs_maxbsize != sblock.fs_bsize) {
 409                 sblock.fs_maxbsize = sblock.fs_bsize;
 410                 sblock.fs_time = sblock.fs_old_time;
 411                 sblock.fs_size = sblock.fs_old_size;
 412                 sblock.fs_dsize = sblock.fs_old_dsize;
 413                 sblock.fs_csaddr = sblock.fs_old_csaddr;
 414                 sblock.fs_cstotal.cs_ndir = sblock.fs_old_cstotal.cs_ndir;
 415                 sblock.fs_cstotal.cs_nbfree = sblock.fs_old_cstotal.cs_nbfree;
 416                 sblock.fs_cstotal.cs_nifree = sblock.fs_old_cstotal.cs_nifree;
 417                 sblock.fs_cstotal.cs_nffree = sblock.fs_old_cstotal.cs_nffree;
 418         }
 419         havesb = 1;
 420         return (1);
 421 }
 422
 423 static void
 424 badsb(int listerr, const char *s)
 425 {
 426
 427         if (!listerr)
 428                 return;
 429         if (preen)
 430                 printf("%s: ", cdevname);
 431         pfatal("BAD SUPER BLOCK: %s\n", s);
 432 }
 433
 434 void
 435 sblock_init(void)
 436 {
 437         struct disklabel *lp;
 438
 439         fswritefd = -1;
 440         fsmodified = 0;
 441         lfdir = 0;
 442         initbarea(&sblk);
 443         initbarea(&asblk);
 444         sblk.b_un.b_buf = malloc(SBLOCKSIZE);
 445         asblk.b_un.b_buf = malloc(SBLOCKSIZE);
 446         if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL)
 447                 errx(EEXIT, "cannot allocate space for superblock");
 448         if ((lp = getdisklabel(NULL, fsreadfd)))
 449                 dev_bsize = secsize = lp->d_secsize;
 450         else
 451                 dev_bsize = secsize = DEV_BSIZE;
 452 }
 453
 454 /*
 455  * Calculate a prototype superblock based on information in the disk label.
 456  * When done the cgsblock macro can be calculated and the fs_ncg field
 457  * can be used. Do NOT attempt to use other macros without verifying that
 458  * their needed information is available!
 459  */
 460 static int
 461 calcsb(char *dev, int devfd, struct fs *fs)
 462 {
 463         struct disklabel *lp;
 464         struct partition *pp;
 465         char *cp;
 466         int i, nspf;
 467
 468         cp = strchr(dev, '\0') - 1;
 469         if (cp == (char *)-1 || ((*cp < 'a' || *cp > 'h') && !isdigit(*cp))) {
 470                 pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
 471                 return (0);
 472         }
 473         lp = getdisklabel(dev, devfd);
 474         if (isdigit(*cp))
 475                 pp = &lp->d_partitions[0];
 476         else
 477                 pp = &lp->d_partitions[*cp - 'a'];
 478         if (pp->p_fstype != FS_BSDFFS) {
 479                 pfatal("%s: NOT LABELED AS A BSD FILE SYSTEM (%s)\n",
 480                         dev, pp->p_fstype < FSMAXTYPES ?
 481                         fstypenames[pp->p_fstype] : "unknown");
 482                 return (0);
 483         }
 484         if (pp->p_fsize == 0 || pp->p_frag == 0 ||
 485             pp->p_cpg == 0 || pp->p_size == 0) {
 486                 pfatal("%s: %s: type %s fsize %d, frag %d, cpg %d, size %d\n",
 487                     dev, "INCOMPLETE LABEL", fstypenames[pp->p_fstype],
 488                     pp->p_fsize, pp->p_frag, pp->p_cpg, pp->p_size);
 489                 return (0);
 490         }
 491         memset(fs, 0, sizeof(struct fs));
 492         fs->fs_fsize = pp->p_fsize;
 493         fs->fs_frag = pp->p_frag;
 494         fs->fs_size = pp->p_size;
 495         fs->fs_sblkno = roundup(
 496                 howmany(lp->d_bbsize + lp->d_sbsize, fs->fs_fsize),
 497                 fs->fs_frag);
 498         nspf = fs->fs_fsize / lp->d_secsize;
 499         for (fs->fs_fsbtodb = 0, i = nspf; i > 1; i >>= 1)
 500                 fs->fs_fsbtodb++;
 501         dev_bsize = lp->d_secsize;
 502         if (fs->fs_magic == FS_UFS2_MAGIC) {
 503                 fs->fs_fpg = pp->p_cpg;
 504                 fs->fs_ncg = howmany(fs->fs_size, fs->fs_fpg);
 505         } else /* if (fs->fs_magic == FS_UFS1_MAGIC) */ {
 506                 fs->fs_old_cpg = pp->p_cpg;
 507                 fs->fs_old_cgmask = 0xffffffff;
 508                 for (i = lp->d_ntracks; i > 1; i >>= 1)
 509                         fs->fs_old_cgmask <<= 1;
 510                 if (!POWEROF2(lp->d_ntracks))
 511                         fs->fs_old_cgmask <<= 1;
 512                 fs->fs_old_cgoffset = roundup(howmany(lp->d_nsectors, nspf),
 513                     fs->fs_frag);
 514                 fs->fs_fpg = (fs->fs_old_cpg * lp->d_secpercyl) / nspf;
 515                 fs->fs_ncg = howmany(fs->fs_size / lp->d_secpercyl,
 516                     fs->fs_old_cpg);
 517         }
 518         return (1);
 519 }
 520
 521 static struct disklabel *
 522 getdisklabel(char *s, int fd)
 523 {
 524         static struct disklabel lab;
 525
 526         if (ioctl(fd, DIOCGDINFO, (char *)&lab) < 0) {
 527                 if (s == NULL)
 528                         return ((struct disklabel *)NULL);
 529                 pwarn("ioctl (GCINFO): %s\n", strerror(errno));
 530                 errx(EEXIT, "%s: can't read disk label", s);
 531         }
 532         return (&lab);
 533 }