sys/kern/vfs_conf.c

   1 /*-
   2  * Copyright (c) 1999 Michael Smith
   3  * All rights reserved.
   4  * Copyright (c) 1999 Poul-Henning Kamp
   5  * 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  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  *      $FreeBSD: src/sys/kern/vfs_conf.c,v 1.49.2.5 2003/01/07 11:56:53 joerg Exp $
  29  *      $DragonFly: src/sys/kern/vfs_conf.c,v 1.31 2007/05/27 18:37:23 dillon Exp $
  30  */
  31
  32 /*
  33  * Locate and mount the root filesystem.
  34  *
  35  * The root filesystem is detailed in the kernel environment variable
  36  * vfs.root.mountfrom, which is expected to be in the general format
  37  *
  38  * <vfsname>:[<path>]
  39  * vfsname   := the name of a VFS known to the kernel and capable
  40  *              of being mounted as root
  41  * path      := disk device name or other data used by the filesystem
  42  *              to locate its physical store
  43  *
  44  */
  45
  46 #include "opt_rootdevname.h"
  47
  48 #include <sys/param.h>
  49 #include <sys/kernel.h>
  50 #include <sys/systm.h>
  51 #include <sys/proc.h>
  52 #include <sys/vnode.h>
  53 #include <sys/mount.h>
  54 #include <sys/malloc.h>
  55 #include <sys/reboot.h>
  56 #include <sys/diskslice.h>
  57 #include <sys/disklabel.h>
  58 #include <sys/conf.h>
  59 #include <sys/cons.h>
  60 #include <sys/device.h>
  61 #include <sys/namecache.h>
  62 #include <sys/paths.h>
  63 #include <sys/thread2.h>
  64
  65 #include "opt_ddb.h"
  66 #ifdef DDB
  67 #include <ddb/ddb.h>
  68 #endif
  69
  70 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
  71
  72 #define ROOTNAME        "root_device"
  73
  74 struct vnode    *rootvnode;
  75 struct nchandle rootnch;
  76
  77 /*
  78  * The root specifiers we will try if RB_CDROM is specified.  Note that
  79  * the ATA driver will accept acd*a and acd*c, but the SCSI driver
  80  * will only accept cd*c, so use 'c'.
  81  *
  82  * XXX TGEN NATA and, presumably, 'old'ATA will also accept the device name
  83  * without any fake partition, since the major & minor are identical for all
  84  * three (acd*, acd*a and acd*c). However, due to an as-of-yet undiscovered
  85  * bug, acd0c ends up with minor 2 when using NATA and booting cold. Since
  86  * NATA's acd_open() is unable to fulfill mounts on such 'ghost' cdevs, acd0
  87  * and acd1 have been added to the list of CD-ROM root device names.
  88  */
  89 static char *cdrom_rootdevnames[] = {
  90         "cd9660:cd0c",
  91         "cd9660:acd0c",
  92         "cd9660:cd1c",
  93         "cd9660:acd1c",
  94         "cd9660:acd0",
  95         "cd9660:acd1",
  96         NULL
  97 };
  98
  99 static void     vfs_mountroot(void *junk);
 100 static int      vfs_mountroot_try(const char *mountfrom);
 101 static int      vfs_mountroot_ask(void);
 102 static int      getline(char *cp, int limit);
 103
 104 /* legacy find-root code */
 105 char            *rootdevnames[2] = {NULL, NULL};
 106 static int      setrootbyname(char *name);
 107
 108 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
 109
 110 /*
 111  * Find and mount the root filesystem
 112  */
 113 static void
 114 vfs_mountroot(void *junk)
 115 {
 116         int     i;
 117         cdev_t  save_rootdev = rootdev;
 118
 119         /*
 120          * The root filesystem information is compiled in, and we are
 121          * booted with instructions to use it.
 122          */
 123 #ifdef ROOTDEVNAME
 124         if ((boothowto & RB_DFLTROOT) &&
 125             !vfs_mountroot_try(ROOTDEVNAME))
 126                 return;
 127 #endif
 128         /*
 129          * We are booted with instructions to prompt for the root filesystem,
 130          * or to use the compiled-in default when it doesn't exist.
 131          */
 132         if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
 133                 if (!vfs_mountroot_ask())
 134                         return;
 135         }
 136
 137         /*
 138          * We've been given the generic "use CDROM as root" flag.  This is
 139          * necessary because one media may be used in many different
 140          * devices, so we need to search for them.
 141          */
 142         if (boothowto & RB_CDROM) {
 143                 for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
 144                         if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
 145                                 return;
 146                 }
 147         }
 148
 149         /*
 150          * Try to use the value read by the loader from /etc/fstab, or
 151          * supplied via some other means.  This is the preferred
 152          * mechanism.
 153          */
 154         if (!vfs_mountroot_try(kgetenv("vfs.root.mountfrom")))
 155                 return;
 156
 157         /*
 158          * If a vfs set rootdev, try it (XXX VINUM HACK!)
 159          */
 160         if (save_rootdev != NULL) {
 161                 rootdev = save_rootdev;
 162                 if (!vfs_mountroot_try(""))
 163                         return;
 164         }
 165
 166         /*
 167          * Try values that may have been computed by the machine-dependant
 168          * legacy code.
 169          */
 170         if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
 171                 return;
 172         if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
 173                 return;
 174
 175         /*
 176          * If we have a compiled-in default, and haven't already tried it, try
 177          * it now.
 178          */
 179 #ifdef ROOTDEVNAME
 180         if (!(boothowto & RB_DFLTROOT))
 181                 if (!vfs_mountroot_try(ROOTDEVNAME))
 182                         return;
 183 #endif
 184
 185         /*
 186          * Everything so far has failed, prompt on the console if we haven't
 187          * already tried that.
 188          */
 189         if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
 190                 return;
 191         panic("Root mount failed, startup aborted.");
 192 }
 193
 194 /*
 195  * Mount (mountfrom) as the root filesystem.
 196  */
 197 static int
 198 vfs_mountroot_try(const char *mountfrom)
 199 {
 200         struct mount    *mp;
 201         char            *vfsname, *devname;
 202         int             error;
 203         char            patt[32];
 204
 205         vfsname = NULL;
 206         devname = NULL;
 207         mp      = NULL;
 208         error   = EINVAL;
 209
 210         if (mountfrom == NULL)
 211                 return(error);          /* don't complain */
 212
 213         crit_enter();
 214         kprintf("Mounting root from %s\n", mountfrom);
 215         crit_exit();
 216
 217         /* parse vfs name and devname */
 218         vfsname = kmalloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
 219         devname = kmalloc(MNAMELEN, M_MOUNT, M_WAITOK);
 220         vfsname[0] = devname[0] = 0;
 221         ksprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
 222         if (ksscanf(mountfrom, patt, vfsname, devname) < 1)
 223                 goto done;
 224
 225         /* allocate a root mount */
 226         error = vfs_rootmountalloc(vfsname,
 227                         devname[0] != 0 ? devname : ROOTNAME, &mp);
 228         if (error != 0) {
 229                 kprintf("Can't allocate root mount for filesystem '%s': %d\n",
 230                        vfsname, error);
 231                 goto done;
 232         }
 233         mp->mnt_flag |= MNT_ROOTFS;
 234
 235         /* do our best to set rootdev */
 236         if ((devname[0] != 0) && setrootbyname(devname))
 237                 kprintf("setrootbyname failed\n");
 238
 239         /* If the root device is a type "memory disk", mount RW */
 240         if (rootdev != NULL && dev_is_good(rootdev) &&
 241             (dev_dflags(rootdev) & D_MEMDISK)) {
 242                 mp->mnt_flag &= ~MNT_RDONLY;
 243         }
 244
 245         error = VFS_MOUNT(mp, NULL, NULL, proc0.p_ucred);
 246
 247 done:
 248         if (vfsname != NULL)
 249                 kfree(vfsname, M_MOUNT);
 250         if (devname != NULL)
 251                 kfree(devname, M_MOUNT);
 252         if (error != 0) {
 253                 if (mp != NULL) {
 254                         vfs_unbusy(mp);
 255                         kfree(mp, M_MOUNT);
 256                 }
 257                 kprintf("Root mount failed: %d\n", error);
 258         } else {
 259                 /* register with list of mounted filesystems */
 260                 mountlist_insert(mp, MNTINS_FIRST);
 261
 262                 /* sanity check system clock against root fs timestamp */
 263                 inittodr(mp->mnt_time);
 264                 vfs_unbusy(mp);
 265         }
 266         return(error);
 267 }
 268
 269 /*
 270  * Spin prompting on the console for a suitable root filesystem
 271  */
 272 static int vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg);
 273
 274 static int
 275 vfs_mountroot_ask(void)
 276 {
 277         char name[128];
 278         int llimit = 100;
 279
 280         kprintf("\nManual root filesystem specification:\n");
 281         kprintf("  <fstype>:<device>  Specify root (e.g. ufs:da0s1a)\n");
 282         kprintf("  ?                  List valid disk boot devices\n");
 283         kprintf("  panic              Just panic\n");
 284         kprintf("  abort              Abort manual input\n");
 285         while (llimit--) {
 286                 kprintf("\nmountroot> ");
 287
 288                 if (getline(name, 128) < 0)
 289                         break;
 290                 if (name[0] == 0) {
 291                         ;
 292                 } else if (name[0] == '?') {
 293                         kprintf("Possibly valid devices for 'ufs' root:\n");
 294                         dev_ops_scan(vfs_mountroot_ask_callback, NULL);
 295                         kprintf("\n");
 296                         continue;
 297                 } else if (strcmp(name, "panic") == 0) {
 298                         panic("panic from console");
 299                 } else if (strcmp(name, "abort") == 0) {
 300                         break;
 301                 } else if (vfs_mountroot_try(name) == 0) {
 302                         return(0);
 303                 }
 304         }
 305         return(1);
 306 }
 307
 308 static
 309 int
 310 vfs_mountroot_ask_callback(struct dev_ops *ops, void *arg __unused)
 311 {
 312         cdev_t dev;
 313
 314         dev = get_dev(ops->head.maj, 0);
 315         if (dev_is_good(dev))
 316                 kprintf(" \"%s\"", dev_dname(dev));
 317         return(0);
 318 }
 319
 320 static int
 321 getline(char *cp, int limit)
 322 {
 323         char *lp;
 324         int c;
 325
 326         lp = cp;
 327         for (;;) {
 328                 c = cngetc();
 329
 330                 switch (c) {
 331                 case -1:
 332                         return(-1);
 333                 case '\n':
 334                 case '\r':
 335                         kprintf("\n");
 336                         *lp++ = '\0';
 337                         return(0);
 338                 case '\b':
 339                 case '\177':
 340                         if (lp > cp) {
 341                                 kprintf("\b \b");
 342                                 lp--;
 343                         } else {
 344                                 kprintf("%c", 7);
 345                         }
 346                         continue;
 347                 case '#':
 348                         kprintf("#");
 349                         lp--;
 350                         if (lp < cp)
 351                                 lp = cp;
 352                         continue;
 353                 case '@':
 354                 case 'u' & 037:
 355                         lp = cp;
 356                         kprintf("%c", '\n');
 357                         continue;
 358                 default:
 359                         if (lp - cp >= limit - 1) {
 360                                 kprintf("%c", 7);
 361                         } else {
 362                                 kprintf("%c", c);
 363                                 *lp++ = c;
 364                         }
 365                         continue;
 366                 }
 367         }
 368 }
 369
 370 /*
 371  * Convert a given name to the cdev_t of the disk-like device
 372  * it refers to.
 373  */
 374 struct kdbn_info {
 375         const char *name;
 376         int nlen;
 377         int minor;
 378         cdev_t dev;
 379 };
 380
 381 static int kgetdiskbyname_callback(struct dev_ops *ops, void *arg);
 382
 383 cdev_t
 384 kgetdiskbyname(const char *name)
 385 {
 386         char *cp;
 387         int nlen;
 388         int unit, slice, part;
 389         cdev_t rdev;
 390         struct kdbn_info info;
 391
 392         /*
 393          * Get the base name of the device
 394          */
 395         if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
 396                 name += sizeof(__SYS_PATH_DEV) - 1;
 397         cp = __DECONST(char *, name);
 398         while (*cp == '/')
 399                 ++cp;
 400         while (*cp >= 'a' && *cp <= 'z')
 401                 ++cp;
 402         if (cp == name) {
 403                 kprintf("missing device name\n");
 404                 return (NULL);
 405         }
 406         nlen = cp - name;
 407
 408         /*
 409          * Get the unit.
 410          */
 411         unit = strtol(cp, &cp, 10);
 412         if (name + nlen == (const char *)cp || unit < 0 || unit >= DKMAXUNITS) {
 413                 kprintf("bad unit: %d\n", unit);
 414                 return (NULL);
 415         }
 416
 417         /*
 418          * Get the slice.  Note that if no partition or partition 'a' is
 419          * specified, and no slice is specified, we will try both 'ad0a'
 420          * (which is what you get when slice is 0), and also 'ad0' (the
 421          * whole-disk partition, slice == 1).
 422          */
 423         if (*cp == 's') {
 424                 slice = cp[1] - '0';
 425                 if (slice >= 1)
 426                         ++slice;
 427                 cp += 2;
 428         } else {
 429                 slice = 0;
 430         }
 431
 432         /*
 433          * Get the partition.
 434          */
 435         if (*cp >= 'a' && *cp <= 'p') {
 436                 part = *cp - 'a';
 437                 ++cp;
 438         } else {
 439                 part = 0;
 440         }
 441
 442         if (*cp != '\0') {
 443                 kprintf("junk after name\n");
 444                 return (NULL);
 445         }
 446
 447         /*
 448          * Locate the device
 449          */
 450         bzero(&info, sizeof(info));
 451         info.nlen = nlen;
 452         info.name = name;
 453         info.minor = dkmakeminor(unit, slice, part);
 454         dev_ops_scan(kgetdiskbyname_callback, &info);
 455         if (info.dev == NULL) {
 456                 kprintf("no such device '%*.*s'\n", nlen, nlen, name);
 457                 return (NULL);
 458         }
 459
 460         /*
 461          * FOUND DEVICE
 462          */
 463         rdev = make_sub_dev(info.dev, info.minor);
 464         return(rdev);
 465 }
 466
 467 static
 468 int
 469 kgetdiskbyname_callback(struct dev_ops *ops, void *arg)
 470 {
 471         struct kdbn_info *info = arg;
 472         cdev_t dev;
 473         const char *dname;
 474
 475         dev = get_dev(ops->head.maj, info->minor);
 476         if (dev_is_good(dev) && (dname = dev_dname(dev)) != NULL) {
 477                 if (strlen(dname) == info->nlen &&
 478                     strncmp(dname, info->name, info->nlen) == 0) {
 479                         info->dev = dev;
 480                         return(-1);
 481                 }
 482         }
 483         return(0);
 484 }
 485
 486 /*
 487  * Set rootdev to match (name), given that we expect it to
 488  * refer to a disk-like device.
 489  */
 490 static int
 491 setrootbyname(char *name)
 492 {
 493         cdev_t diskdev;
 494
 495         diskdev = kgetdiskbyname(name);
 496         if (diskdev != NULL) {
 497                 rootdev = diskdev;
 498                 return (0);
 499         }
 500
 501         return (1);
 502 }
 503
 504 #ifdef DDB
 505 DB_SHOW_COMMAND(disk, db_getdiskbyname)
 506 {
 507         cdev_t dev;
 508
 509         if (modif[0] == '\0') {
 510                 db_error("usage: show disk/devicename");
 511                 return;
 512         }
 513         dev = kgetdiskbyname(modif);
 514         if (dev != NULL)
 515                 db_printf("cdev_t = %p\n", dev);
 516         else
 517                 db_printf("No disk device matched.\n");
 518 }
 519 #endif