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 1.34 2008/05/24 19:08:28 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/conf.h>
  58 #include <sys/cons.h>
  59 #include <sys/device.h>
  60 #include <sys/disk.h>
  61 #include <sys/namecache.h>
  62 #include <sys/paths.h>
  63 #include <sys/thread2.h>
  64 #include <sys/nlookup.h>
  65 #include <sys/devfs.h>
  66
  67 #include "opt_ddb.h"
  68 #ifdef DDB
  69 #include <ddb/ddb.h>
  70 #endif
  71
  72 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
  73
  74 #define ROOTNAME        "root_device"
  75
  76 struct vnode    *rootvnode;
  77 struct nchandle rootnch;
  78
  79 /*
  80  * The root specifiers we will try if RB_CDROM is specified.  Note that
  81  * with DEVFS we do not use the compatibility slice's whole-disk 'c'
  82  * partition.  Instead we just use the whole disk, e.g. cd0 or cd0s0.
  83  */
  84 static char *cdrom_rootdevnames[] = {
  85         "cd9660:cd0",   /* SCSI (including AHCI and SILI) */
  86         "cd9660:acd0",  /* NATA */
  87         "cd9660:cd1",   /* SCSI (including AHCI and SILI) */
  88         "cd9660:acd1",  /* NATA */
  89         "cd9660:cd8",   /* USB */
  90         "cd9660:cd9",   /* USB */
  91         NULL
  92 };
  93
  94 int vfs_mountroot_devfs(void);
  95 static void     vfs_mountroot(void *junk);
  96 static int      vfs_mountroot_try(const char *mountfrom);
  97 static int      vfs_mountroot_ask(void);
  98 static int      getline(char *cp, int limit);
  99
 100 /* legacy find-root code */
 101 char            *rootdevnames[2] = {NULL, NULL};
 102 static int      setrootbyname(char *name);
 103
 104 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
 105
 106 /*
 107  * Find and mount the root filesystem
 108  */
 109 static void
 110 vfs_mountroot(void *junk)
 111 {
 112         int     i;
 113         cdev_t  save_rootdev = rootdev;
 114
 115         /*
 116          * Make sure all disk devices created so far have also been probed,
 117          * and also make sure that the newly created device nodes for
 118          * probed disks are ready, too.
 119          *
 120          * Messages can fly around here so get good synchronization
 121          * coverage.
 122          */
 123         sync_devs();
 124
 125         /*
 126          * The root filesystem information is compiled in, and we are
 127          * booted with instructions to use it.
 128          */
 129 #ifdef ROOTDEVNAME
 130         if ((boothowto & RB_DFLTROOT) &&
 131             !vfs_mountroot_try(ROOTDEVNAME))
 132                 return;
 133 #endif
 134         /*
 135          * We are booted with instructions to prompt for the root filesystem,
 136          * or to use the compiled-in default when it doesn't exist.
 137          */
 138         if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
 139                 if (!vfs_mountroot_ask())
 140                         return;
 141         }
 142
 143         /*
 144          * We've been given the generic "use CDROM as root" flag.  This is
 145          * necessary because one media may be used in many different
 146          * devices, so we need to search for them.
 147          */
 148         if (boothowto & RB_CDROM) {
 149                 for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
 150                         if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
 151                                 return;
 152                 }
 153         }
 154
 155         /*
 156          * Try to use the value read by the loader from /etc/fstab, or
 157          * supplied via some other means.  This is the preferred
 158          * mechanism.
 159          */
 160         if (!vfs_mountroot_try(kgetenv("vfs.root.mountfrom")))
 161                 return;
 162
 163         /*
 164          * If a vfs set rootdev, try it (XXX VINUM HACK!)
 165          */
 166         if (save_rootdev != NULL) {
 167                 rootdev = save_rootdev;
 168                 if (!vfs_mountroot_try(""))
 169                         return;
 170         }
 171
 172         /*
 173          * Try values that may have been computed by the machine-dependant
 174          * legacy code.
 175          */
 176         if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
 177                 return;
 178         if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
 179                 return;
 180
 181         /*
 182          * If we have a compiled-in default, and haven't already tried it, try
 183          * it now.
 184          */
 185 #ifdef ROOTDEVNAME
 186         if (!(boothowto & RB_DFLTROOT))
 187                 if (!vfs_mountroot_try(ROOTDEVNAME))
 188                         return;
 189 #endif
 190
 191         /*
 192          * Everything so far has failed, prompt on the console if we haven't
 193          * already tried that.
 194          */
 195         if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
 196                 return;
 197         panic("Root mount failed, startup aborted.");
 198 }
 199
 200
 201 int
 202 vfs_mountroot_devfs(void)
 203 {
 204         struct vnode *vp;
 205         struct nchandle nch;
 206         struct nlookupdata nd;
 207         struct mount *mp;
 208         struct vfsconf *vfsp;
 209         int error;
 210         struct ucred *cred = proc0.p_ucred;
 211
 212         /*
 213          * Lookup the requested path and extract the nch and vnode.
 214          */
 215         error = nlookup_init_raw(&nd,
 216              "/dev", UIO_SYSSPACE, NLC_FOLLOW,
 217              cred, &rootnch);
 218
 219         if (error == 0) {
 220                 devfs_debug(DEVFS_DEBUG_DEBUG, "vfs_mountroot_devfs: nlookup_init is ok...\n");
 221                 if ((error = nlookup(&nd)) == 0) {
 222                         devfs_debug(DEVFS_DEBUG_DEBUG, "vfs_mountroot_devfs: nlookup is ok...\n");
 223                         if (nd.nl_nch.ncp->nc_vp == NULL) {
 224                                 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: nlookup: simply not found\n");
 225                                 error = ENOENT;
 226                         }
 227                 }
 228         }
 229         if (error) {
 230                 nlookup_done(&nd);
 231                 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: nlookup failed, error: %d\n", error);
 232                 return (error);
 233         }
 234
 235         /*
 236          * Extract the locked+refd ncp and cleanup the nd structure
 237          */
 238         nch = nd.nl_nch;
 239         cache_zero(&nd.nl_nch);
 240         nlookup_done(&nd);
 241
 242         /*
 243          * now we have the locked ref'd nch and unreferenced vnode.
 244          */
 245         vp = nch.ncp->nc_vp;
 246         if ((error = vget(vp, LK_EXCLUSIVE)) != 0) {
 247                 cache_put(&nch);
 248                 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: vget failed\n");
 249                 return (error);
 250         }
 251         cache_unlock(&nch);
 252
 253         if ((error = vinvalbuf(vp, V_SAVE, 0, 0)) != 0) {
 254                 cache_drop(&nch);
 255                 vput(vp);
 256                 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: vinvalbuf failed\n");
 257                 return (error);
 258         }
 259         if (vp->v_type != VDIR) {
 260                 cache_drop(&nch);
 261                 vput(vp);
 262                 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: vp is not VDIR\n");
 263                 return (ENOTDIR);
 264         }
 265
 266         vfsp = vfsconf_find_by_name("devfs");
 267         vp->v_flag |= VMOUNT;
 268
 269         /*
 270          * Allocate and initialize the filesystem.
 271          */
 272         mp = kmalloc(sizeof(struct mount), M_MOUNT, M_ZERO|M_WAITOK);
 273         TAILQ_INIT(&mp->mnt_nvnodelist);
 274         TAILQ_INIT(&mp->mnt_reservedvnlist);
 275         TAILQ_INIT(&mp->mnt_jlist);
 276         mp->mnt_nvnodelistsize = 0;
 277         lockinit(&mp->mnt_lock, "vfslock", 0, 0);
 278         vfs_busy(mp, LK_NOWAIT);
 279         mp->mnt_op = vfsp->vfc_vfsops;
 280         mp->mnt_vfc = vfsp;
 281         vfsp->vfc_refcount++;
 282         mp->mnt_stat.f_type = vfsp->vfc_typenum;
 283         mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
 284         strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
 285         mp->mnt_stat.f_owner = cred->cr_uid;
 286         mp->mnt_iosize_max = DFLTPHYS;
 287         vn_unlock(vp);
 288
 289         /*
 290          * Mount the filesystem.
 291          */
 292         error = VFS_MOUNT(mp, "/dev", NULL, cred);
 293
 294         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 295
 296         /*
 297          * Put the new filesystem on the mount list after root.  The mount
 298          * point gets its own mnt_ncmountpt (unless the VFS already set one
 299          * up) which represents the root of the mount.  The lookup code
 300          * detects the mount point going forward and checks the root of
 301          * the mount going backwards.
 302          *
 303          * It is not necessary to invalidate or purge the vnode underneath
 304          * because elements under the mount will be given their own glue
 305          * namecache record.
 306          */
 307         if (!error) {
 308                 if (mp->mnt_ncmountpt.ncp == NULL) {
 309                         /*
 310                          * allocate, then unlock, but leave the ref intact
 311                          */
 312                         cache_allocroot(&mp->mnt_ncmountpt, mp, NULL);
 313                         cache_unlock(&mp->mnt_ncmountpt);
 314                 }
 315                 mp->mnt_ncmounton = nch;                /* inherits ref */
 316                 nch.ncp->nc_flag |= NCF_ISMOUNTPT;
 317
 318                 /* XXX get the root of the fs and cache_setvp(mnt_ncmountpt...) */
 319                 vp->v_flag &= ~VMOUNT;
 320                 mountlist_insert(mp, MNTINS_LAST);
 321                 vn_unlock(vp);
 322                 //checkdirs(&mp->mnt_ncmounton, &mp->mnt_ncmountpt);
 323                 error = vfs_allocate_syncvnode(mp);
 324                 if (error) {
 325                         devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: vfs_allocate_syncvnode failed\n");
 326                 }
 327                 vfs_unbusy(mp);
 328                 error = VFS_START(mp, 0);
 329                 vrele(vp);
 330         } else {
 331                 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
 332                 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
 333                 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
 334                 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
 335                 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
 336                 vp->v_flag &= ~VMOUNT;
 337                 mp->mnt_vfc->vfc_refcount--;
 338                 vfs_unbusy(mp);
 339                 kfree(mp, M_MOUNT);
 340                 cache_drop(&nch);
 341                 vput(vp);
 342                 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: mount failed\n");
 343         }
 344
 345         devfs_debug(DEVFS_DEBUG_DEBUG, "rootmount_devfs done with error: %d\n", error);
 346         return (error);
 347 }
 348
 349
 350 /*
 351  * Mount (mountfrom) as the root filesystem.
 352  */
 353 static int
 354 vfs_mountroot_try(const char *mountfrom)
 355 {
 356         struct mount    *mp, *mp2;
 357         char            *vfsname, *devname;
 358         int             error;
 359         char            patt[32];
 360
 361         vfsname = NULL;
 362         devname = NULL;
 363         mp      = NULL;
 364         mp2             = NULL;
 365         error   = EINVAL;
 366
 367         if (mountfrom == NULL)
 368                 return(error);          /* don't complain */
 369
 370         crit_enter();
 371         kprintf("Mounting root from %s\n", mountfrom);
 372         crit_exit();
 373
 374         /* parse vfs name and devname */
 375         vfsname = kmalloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
 376         devname = kmalloc(MNAMELEN, M_MOUNT, M_WAITOK);
 377         vfsname[0] = devname[0] = 0;
 378         ksprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
 379         if (ksscanf(mountfrom, patt, vfsname, devname) < 1)
 380                 goto done;
 381
 382         /* allocate a root mount */
 383         error = vfs_rootmountalloc(vfsname,
 384                         devname[0] != 0 ? devname : ROOTNAME, &mp);
 385         if (error != 0) {
 386                 kprintf("Can't allocate root mount for filesystem '%s': %d\n",
 387                        vfsname, error);
 388                 goto done;
 389         }
 390         mp->mnt_flag |= MNT_ROOTFS;
 391
 392         /* do our best to set rootdev */
 393         if ((devname[0] != 0) && setrootbyname(devname))
 394                 kprintf("setrootbyname failed\n");
 395
 396         /* If the root device is a type "memory disk", mount RW */
 397         if (rootdev != NULL && dev_is_good(rootdev) &&
 398             (dev_dflags(rootdev) & D_MEMDISK)) {
 399                 mp->mnt_flag &= ~MNT_RDONLY;
 400         }
 401
 402         error = VFS_MOUNT(mp, NULL, NULL, proc0.p_ucred);
 403
 404         if (!error) {
 405                 //kprintf("Trying vfs_mountroot_devfs!\n");
 406                 //vfs_mountroot_devfs();
 407         }
 408
 409 done:
 410         if (vfsname != NULL)
 411                 kfree(vfsname, M_MOUNT);
 412         if (devname != NULL)
 413                 kfree(devname, M_MOUNT);
 414         if (error == 0) {
 415                 /* register with list of mounted filesystems */
 416                 mountlist_insert(mp, MNTINS_FIRST);
 417
 418                 /* sanity check system clock against root fs timestamp */
 419                 inittodr(mp->mnt_time);
 420                 vfs_unbusy(mp);
 421                 if (mp->mnt_syncer == NULL) {
 422                         error = vfs_allocate_syncvnode(mp);
 423                         if (error)
 424                                 kprintf("Warning: no syncer vp for root!\n");
 425                         error = 0;
 426                 }
 427         } else {
 428                 if (mp != NULL) {
 429                         vfs_unbusy(mp);
 430                         kfree(mp, M_MOUNT);
 431                 }
 432                 kprintf("Root mount failed: %d\n", error);
 433         }
 434         return(error);
 435 }
 436
 437
 438 static void vfs_mountroot_ask_callback(cdev_t);
 439
 440 /*
 441  * Spin prompting on the console for a suitable root filesystem
 442  */
 443
 444 static int
 445 vfs_mountroot_ask(void)
 446 {
 447         char name[128];
 448         int llimit = 100;
 449
 450         kprintf("\nManual root filesystem specification:\n");
 451         kprintf("  <fstype>:<device>  Specify root (e.g. ufs:da0s1a)\n");
 452         kprintf("  ?                  List valid disk boot devices\n");
 453         kprintf("  panic              Just panic\n");
 454         kprintf("  abort              Abort manual input\n");
 455         while (llimit--) {
 456                 kprintf("\nmountroot> ");
 457
 458                 if (getline(name, 128) < 0)
 459                         break;
 460                 if (name[0] == 0) {
 461                         ;
 462                 } else if (name[0] == '?') {
 463                         kprintf("Possibly valid devices for root FS:\n");
 464                         //enumerate all disk devices
 465                         devfs_scan_callback(vfs_mountroot_ask_callback);
 466                         kprintf("\n");
 467                         continue;
 468                 } else if (strcmp(name, "panic") == 0) {
 469                         panic("panic from console");
 470                 } else if (strcmp(name, "abort") == 0) {
 471                         break;
 472                 } else if (vfs_mountroot_try(name) == 0) {
 473                         return(0);
 474                 }
 475         }
 476         return(1);
 477 }
 478
 479
 480 static void
 481 vfs_mountroot_ask_callback(cdev_t dev)
 482 {
 483         if (dev_is_good(dev) && (dev_dflags(dev) & D_DISK))
 484                 kprintf(" \"%s\" ", dev->si_name);
 485 }
 486
 487
 488 static int
 489 getline(char *cp, int limit)
 490 {
 491         char *lp;
 492         int c;
 493
 494         lp = cp;
 495         for (;;) {
 496                 c = cngetc();
 497
 498                 switch (c) {
 499                 case -1:
 500                         return(-1);
 501                 case '\n':
 502                 case '\r':
 503                         kprintf("\n");
 504                         *lp++ = '\0';
 505                         return(0);
 506                 case '\b':
 507                 case '\177':
 508                         if (lp > cp) {
 509                                 kprintf("\b \b");
 510                                 lp--;
 511                         } else {
 512                                 kprintf("%c", 7);
 513                         }
 514                         continue;
 515                 case '#':
 516                         kprintf("#");
 517                         lp--;
 518                         if (lp < cp)
 519                                 lp = cp;
 520                         continue;
 521                 case '@':
 522                 case 'u' & 037:
 523                         lp = cp;
 524                         kprintf("%c", '\n');
 525                         continue;
 526                 default:
 527                         if (lp - cp >= limit - 1) {
 528                                 kprintf("%c", 7);
 529                         } else {
 530                                 kprintf("%c", c);
 531                                 *lp++ = c;
 532                         }
 533                         continue;
 534                 }
 535         }
 536 }
 537
 538 /*
 539  * Convert a given name to the cdev_t of the disk-like device
 540  * it refers to.
 541  */
 542 struct kdbn_info {
 543         const char *name;
 544         int nlen;
 545         int minor;
 546         cdev_t dev;
 547 };
 548
 549
 550 cdev_t
 551 kgetdiskbyname(const char *name)
 552 {
 553         char *cp;
 554         cdev_t rdev;
 555
 556         /*
 557          * Get the base name of the device
 558          */
 559         if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
 560                 name += sizeof(__SYS_PATH_DEV) - 1;
 561         cp = __DECONST(char *, name);
 562
 563         /*
 564          * Locate the device
 565          */
 566         kprintf("tryroot %s\n", name);
 567         rdev = devfs_find_device_by_name(name);
 568         if (rdev == NULL) {
 569                 kprintf("no disk named '%s'\n", name);
 570         }
 571         /*
 572          * FOUND DEVICE
 573          */
 574         return(rdev);
 575 }
 576
 577 /*
 578  * Set rootdev to match (name), given that we expect it to
 579  * refer to a disk-like device.
 580  */
 581 static int
 582 setrootbyname(char *name)
 583 {
 584         cdev_t diskdev;
 585
 586         diskdev = kgetdiskbyname(name);
 587         if (diskdev != NULL) {
 588                 rootdev = diskdev;
 589                 return (0);
 590         }
 591         /* set to NULL if kgetdiskbyname() fails so that if the first rootdev is
 592          * found by fails to mount and the second one isn't found, mountroot_try
 593          * doesn't try again with the first one
 594          */
 595         rootdev = NULL;
 596         return (1);
 597 }
 598
 599 #ifdef DDB
 600 DB_SHOW_COMMAND(disk, db_getdiskbyname)
 601 {
 602         cdev_t dev;
 603
 604         if (modif[0] == '\0') {
 605                 db_error("usage: show disk/devicename");
 606                 return;
 607         }
 608         dev = kgetdiskbyname(modif);
 609         if (dev != NULL)
 610                 db_printf("cdev_t = %p\n", dev);
 611         else
 612                 db_printf("No disk device matched.\n");
 613 }
 614 #endif