vfs_mountroot.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 2010 Marcel Moolenaar
    5  * Copyright (c) 1999-2004 Poul-Henning Kamp
    6  * Copyright (c) 1999 Michael Smith
    7  * Copyright (c) 1989, 1993
    8  *      The Regents of the University of California.  All rights reserved.
    9  * (c) UNIX System Laboratories, Inc.
   10  * All or some portions of this file are derived from material licensed
   11  * to the University of California by American Telephone and Telegraph
   12  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   13  * the permission of UNIX System Laboratories, Inc.
   14  *
   15  * Redistribution and use in source and binary forms, with or without
   16  * modification, are permitted provided that the following conditions
   17  * are met:
   18  * 1. Redistributions of source code must retain the above copyright
   19  *    notice, this list of conditions and the following disclaimer.
   20  * 2. Redistributions in binary form must reproduce the above copyright
   21  *    notice, this list of conditions and the following disclaimer in the
   22  *    documentation and/or other materials provided with the distribution.
   23  * 3. Neither the name of the University nor the names of its contributors
   24  *    may be used to endorse or promote products derived from this software
   25  *    without specific prior written permission.
   26  *
   27  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   37  * SUCH DAMAGE.
   38  */
   39 
   40 #include "opt_rootdevname.h"
   41 
   42 #include <sys/cdefs.h>
   43 __FBSDID("$FreeBSD$");
   44 
   45 #include <sys/param.h>
   46 #include <sys/conf.h>
   47 #include <sys/cons.h>
   48 #include <sys/eventhandler.h>
   49 #include <sys/fcntl.h>
   50 #include <sys/jail.h>
   51 #include <sys/kernel.h>
   52 #include <sys/malloc.h>
   53 #include <sys/mdioctl.h>
   54 #include <sys/mount.h>
   55 #include <sys/mutex.h>
   56 #include <sys/namei.h>
   57 #include <sys/priv.h>
   58 #include <sys/proc.h>
   59 #include <sys/filedesc.h>
   60 #include <sys/reboot.h>
   61 #include <sys/sbuf.h>
   62 #include <sys/stat.h>
   63 #include <sys/syscallsubr.h>
   64 #include <sys/sysproto.h>
   65 #include <sys/sx.h>
   66 #include <sys/sysctl.h>
   67 #include <sys/sysent.h>
   68 #include <sys/systm.h>
   69 #include <sys/vnode.h>
   70 
   71 #include <geom/geom.h>
   72 
   73 /*
   74  * The root filesystem is detailed in the kernel environment variable
   75  * vfs.root.mountfrom, which is expected to be in the general format
   76  *
   77  * <vfsname>:[<path>][  <vfsname>:[<path>] ...]
   78  * vfsname   := the name of a VFS known to the kernel and capable
   79  *              of being mounted as root
   80  * path      := disk device name or other data used by the filesystem
   81  *              to locate its physical store
   82  *
   83  * If the environment variable vfs.root.mountfrom is a space separated list,
   84  * each list element is tried in turn and the root filesystem will be mounted
   85  * from the first one that succeeds.
   86  *
   87  * The environment variable vfs.root.mountfrom.options is a comma delimited
   88  * set of string mount options.  These mount options must be parseable
   89  * by nmount() in the kernel.
   90  */
   91 
   92 static int parse_mount(char **);
   93 static struct mntarg *parse_mountroot_options(struct mntarg *, const char *);
   94 static int sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS);
   95 static void vfs_mountroot_wait(void);
   96 static int vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev);
   97 
   98 /*
   99  * The vnode of the system's root (/ in the filesystem, without chroot
  100  * active.)
  101  */
  102 struct vnode *rootvnode;
  103 
  104 /*
  105  * Mount of the system's /dev.
  106  */
  107 struct mount *rootdevmp;
  108 
  109 char *rootdevnames[2] = {NULL, NULL};
  110 
  111 struct mtx root_holds_mtx;
  112 MTX_SYSINIT(root_holds, &root_holds_mtx, "root_holds", MTX_DEF);
  113 
  114 static TAILQ_HEAD(, root_hold_token)    root_holds =
  115     TAILQ_HEAD_INITIALIZER(root_holds);
  116 
  117 enum action {
  118         A_CONTINUE,
  119         A_PANIC,
  120         A_REBOOT,
  121         A_RETRY
  122 };
  123 
  124 enum rh_flags {
  125         RH_FREE,
  126         RH_ALLOC,
  127         RH_ARG,
  128 };
  129 
  130 static enum action root_mount_onfail = A_CONTINUE;
  131 
  132 static int root_mount_mddev;
  133 static int root_mount_complete;
  134 
  135 /* By default wait up to 3 seconds for devices to appear. */
  136 static int root_mount_timeout = 3;
  137 TUNABLE_INT("vfs.mountroot.timeout", &root_mount_timeout);
  138 
  139 static int root_mount_always_wait = 0;
  140 SYSCTL_INT(_vfs, OID_AUTO, root_mount_always_wait, CTLFLAG_RDTUN,
  141     &root_mount_always_wait, 0,
  142     "Wait for root mount holds even if the root device already exists");
  143 
  144 SYSCTL_PROC(_vfs, OID_AUTO, root_mount_hold,
  145     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
  146     NULL, 0, sysctl_vfs_root_mount_hold, "A",
  147     "List of root mount hold tokens");
  148 
  149 static int
  150 sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS)
  151 {
  152         struct sbuf sb;
  153         struct root_hold_token *h;
  154         int error;
  155 
  156         sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
  157 
  158         mtx_lock(&root_holds_mtx);
  159         TAILQ_FOREACH(h, &root_holds, list) {
  160                 if (h != TAILQ_FIRST(&root_holds))
  161                         sbuf_putc(&sb, ' ');
  162                 sbuf_printf(&sb, "%s", h->who);
  163         }
  164         mtx_unlock(&root_holds_mtx);
  165 
  166         error = sbuf_finish(&sb);
  167         if (error == 0)
  168                 error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
  169         sbuf_delete(&sb);
  170         return (error);
  171 }
  172 
  173 struct root_hold_token *
  174 root_mount_hold(const char *identifier)
  175 {
  176         struct root_hold_token *h;
  177 
  178         h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
  179         h->flags = RH_ALLOC;
  180         h->who = identifier;
  181         mtx_lock(&root_holds_mtx);
  182         TSHOLD("root mount");
  183         TAILQ_INSERT_TAIL(&root_holds, h, list);
  184         mtx_unlock(&root_holds_mtx);
  185         return (h);
  186 }
  187 
  188 void
  189 root_mount_hold_token(const char *identifier, struct root_hold_token *h)
  190 {
  191 #ifdef INVARIANTS
  192         struct root_hold_token *t;
  193 #endif
  194 
  195         h->flags = RH_ARG;
  196         h->who = identifier;
  197         mtx_lock(&root_holds_mtx);
  198 #ifdef INVARIANTS
  199         TAILQ_FOREACH(t, &root_holds, list) {
  200                 if (t == h) {
  201                         panic("Duplicate mount hold by '%s' on %p",
  202                             identifier, h);
  203                 }
  204         }
  205 #endif
  206         TSHOLD("root mount");
  207         TAILQ_INSERT_TAIL(&root_holds, h, list);
  208         mtx_unlock(&root_holds_mtx);
  209 }
  210 
  211 void
  212 root_mount_rel(struct root_hold_token *h)
  213 {
  214 
  215         if (h == NULL || h->flags == RH_FREE)
  216                 return;
  217 
  218         mtx_lock(&root_holds_mtx);
  219         TAILQ_REMOVE(&root_holds, h, list);
  220         TSRELEASE("root mount");
  221         wakeup(&root_holds);
  222         mtx_unlock(&root_holds_mtx);
  223         if (h->flags == RH_ALLOC) {
  224                 free(h, M_DEVBUF);
  225         } else
  226                 h->flags = RH_FREE;
  227 }
  228 
  229 int
  230 root_mounted(void)
  231 {
  232 
  233         /* No mutex is acquired here because int stores are atomic. */
  234         return (root_mount_complete);
  235 }
  236 
  237 static void
  238 set_rootvnode(void)
  239 {
  240 
  241         if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
  242                 panic("set_rootvnode: Cannot find root vnode");
  243 
  244         VOP_UNLOCK(rootvnode);
  245 
  246         pwd_set_rootvnode();
  247 }
  248 
  249 static int
  250 vfs_mountroot_devfs(struct thread *td, struct mount **mpp)
  251 {
  252         struct vfsoptlist *opts;
  253         struct vfsconf *vfsp;
  254         struct mount *mp;
  255         int error;
  256 
  257         *mpp = NULL;
  258 
  259         if (rootdevmp != NULL) {
  260                 /*
  261                  * Already have /dev; this happens during rerooting.
  262                  */
  263                 error = vfs_busy(rootdevmp, 0);
  264                 if (error != 0)
  265                         return (error);
  266                 *mpp = rootdevmp;
  267         } else {
  268                 vfsp = vfs_byname("devfs");
  269                 KASSERT(vfsp != NULL, ("Could not find devfs by name"));
  270                 if (vfsp == NULL)
  271                         return (ENOENT);
  272 
  273                 mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
  274 
  275                 error = VFS_MOUNT(mp);
  276                 KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
  277                 if (error)
  278                         return (error);
  279 
  280                 error = VFS_STATFS(mp, &mp->mnt_stat);
  281                 KASSERT(error == 0, ("VFS_STATFS(devfs) failed %d", error));
  282                 if (error)
  283                         return (error);
  284 
  285                 opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
  286                 TAILQ_INIT(opts);
  287                 mp->mnt_opt = opts;
  288 
  289                 mtx_lock(&mountlist_mtx);
  290                 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
  291                 mtx_unlock(&mountlist_mtx);
  292 
  293                 *mpp = mp;
  294                 rootdevmp = mp;
  295                 vfs_op_exit(mp);
  296         }
  297 
  298         set_rootvnode();
  299 
  300         error = kern_symlinkat(td, "/", AT_FDCWD, "dev", UIO_SYSSPACE);
  301         if (error)
  302                 printf("kern_symlink /dev -> / returns %d\n", error);
  303 
  304         return (error);
  305 }
  306 
  307 static void
  308 vfs_mountroot_shuffle(struct thread *td, struct mount *mpdevfs)
  309 {
  310         struct nameidata nd;
  311         struct mount *mporoot, *mpnroot;
  312         struct vnode *vp, *vporoot, *vpdevfs;
  313         char *fspath;
  314         int error;
  315 
  316         mpnroot = TAILQ_NEXT(mpdevfs, mnt_list);
  317 
  318         /* Shuffle the mountlist. */
  319         mtx_lock(&mountlist_mtx);
  320         mporoot = TAILQ_FIRST(&mountlist);
  321         TAILQ_REMOVE(&mountlist, mpdevfs, mnt_list);
  322         if (mporoot != mpdevfs) {
  323                 TAILQ_REMOVE(&mountlist, mpnroot, mnt_list);
  324                 TAILQ_INSERT_HEAD(&mountlist, mpnroot, mnt_list);
  325         }
  326         TAILQ_INSERT_TAIL(&mountlist, mpdevfs, mnt_list);
  327         mtx_unlock(&mountlist_mtx);
  328 
  329         cache_purgevfs(mporoot);
  330         if (mporoot != mpdevfs)
  331                 cache_purgevfs(mpdevfs);
  332 
  333         if (VFS_ROOT(mporoot, LK_EXCLUSIVE, &vporoot))
  334                 panic("vfs_mountroot_shuffle: Cannot find root vnode");
  335 
  336         VI_LOCK(vporoot);
  337         vporoot->v_iflag &= ~VI_MOUNT;
  338         vn_irflag_unset_locked(vporoot, VIRF_MOUNTPOINT);
  339         vporoot->v_mountedhere = NULL;
  340         VI_UNLOCK(vporoot);
  341         mporoot->mnt_flag &= ~MNT_ROOTFS;
  342         mporoot->mnt_vnodecovered = NULL;
  343         vput(vporoot);
  344 
  345         /* Set up the new rootvnode, and purge the cache */
  346         mpnroot->mnt_vnodecovered = NULL;
  347         set_rootvnode();
  348         cache_purgevfs(rootvnode->v_mount);
  349 
  350         if (mporoot != mpdevfs) {
  351                 /* Remount old root under /.mount or /mnt */
  352                 fspath = "/.mount";
  353                 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  354                     fspath, td);
  355                 error = namei(&nd);
  356                 if (error) {
  357                         NDFREE(&nd, NDF_ONLY_PNBUF);
  358                         fspath = "/mnt";
  359                         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  360                             fspath, td);
  361                         error = namei(&nd);
  362                 }
  363                 if (!error) {
  364                         vp = nd.ni_vp;
  365                         error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
  366                         if (!error)
  367                                 error = vinvalbuf(vp, V_SAVE, 0, 0);
  368                         if (!error) {
  369                                 cache_purge(vp);
  370                                 mporoot->mnt_vnodecovered = vp;
  371                                 vp->v_mountedhere = mporoot;
  372                                 strlcpy(mporoot->mnt_stat.f_mntonname,
  373                                     fspath, MNAMELEN);
  374                                 VOP_UNLOCK(vp);
  375                         } else
  376                                 vput(vp);
  377                 }
  378                 NDFREE(&nd, NDF_ONLY_PNBUF);
  379 
  380                 if (error)
  381                         printf("mountroot: unable to remount previous root "
  382                             "under /.mount or /mnt (error %d)\n", error);
  383         }
  384 
  385         /* Remount devfs under /dev */
  386         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
  387         error = namei(&nd);
  388         if (!error) {
  389                 vp = nd.ni_vp;
  390                 error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
  391                 if (!error)
  392                         error = vinvalbuf(vp, V_SAVE, 0, 0);
  393                 if (!error) {
  394                         vpdevfs = mpdevfs->mnt_vnodecovered;
  395                         if (vpdevfs != NULL) {
  396                                 cache_purge(vpdevfs);
  397                                 VI_LOCK(vpdevfs);
  398                                 vn_irflag_unset_locked(vpdevfs, VIRF_MOUNTPOINT);
  399                                 vpdevfs->v_mountedhere = NULL;
  400                                 VI_UNLOCK(vpdevfs);
  401                                 vrele(vpdevfs);
  402                         }
  403                         VI_LOCK(vp);
  404                         mpdevfs->mnt_vnodecovered = vp;
  405                         vn_irflag_set_locked(vp, VIRF_MOUNTPOINT);
  406                         vp->v_mountedhere = mpdevfs;
  407                         VI_UNLOCK(vp);
  408                         VOP_UNLOCK(vp);
  409                 } else
  410                         vput(vp);
  411         }
  412         if (error)
  413                 printf("mountroot: unable to remount devfs under /dev "
  414                     "(error %d)\n", error);
  415         NDFREE(&nd, NDF_ONLY_PNBUF);
  416 
  417         if (mporoot == mpdevfs) {
  418                 vfs_unbusy(mpdevfs);
  419                 /* Unlink the no longer needed /dev/dev -> / symlink */
  420                 error = kern_funlinkat(td, AT_FDCWD, "/dev/dev", FD_NONE,
  421                     UIO_SYSSPACE, 0, 0);
  422                 if (error)
  423                         printf("mountroot: unable to unlink /dev/dev "
  424                             "(error %d)\n", error);
  425         }
  426 }
  427 
  428 /*
  429  * Configuration parser.
  430  */
  431 
  432 /* Parser character classes. */
  433 #define CC_WHITESPACE           -1
  434 #define CC_NONWHITESPACE        -2
  435 
  436 /* Parse errors. */
  437 #define PE_EOF                  -1
  438 #define PE_EOL                  -2
  439 
  440 static __inline int
  441 parse_peek(char **conf)
  442 {
  443 
  444         return (**conf);
  445 }
  446 
  447 static __inline void
  448 parse_poke(char **conf, int c)
  449 {
  450 
  451         **conf = c;
  452 }
  453 
  454 static __inline void
  455 parse_advance(char **conf)
  456 {
  457 
  458         (*conf)++;
  459 }
  460 
  461 static int
  462 parse_skipto(char **conf, int mc)
  463 {
  464         int c, match;
  465 
  466         while (1) {
  467                 c = parse_peek(conf);
  468                 if (c == 0)
  469                         return (PE_EOF);
  470                 switch (mc) {
  471                 case CC_WHITESPACE:
  472                         match = (c == ' ' || c == '\t' || c == '\n') ? 1 : 0;
  473                         break;
  474                 case CC_NONWHITESPACE:
  475                         if (c == '\n')
  476                                 return (PE_EOL);
  477                         match = (c != ' ' && c != '\t') ? 1 : 0;
  478                         break;
  479                 default:
  480                         match = (c == mc) ? 1 : 0;
  481                         break;
  482                 }
  483                 if (match)
  484                         break;
  485                 parse_advance(conf);
  486         }
  487         return (0);
  488 }
  489 
  490 static int
  491 parse_token(char **conf, char **tok)
  492 {
  493         char *p;
  494         size_t len;
  495         int error;
  496 
  497         *tok = NULL;
  498         error = parse_skipto(conf, CC_NONWHITESPACE);
  499         if (error)
  500                 return (error);
  501         p = *conf;
  502         error = parse_skipto(conf, CC_WHITESPACE);
  503         len = *conf - p;
  504         *tok = malloc(len + 1, M_TEMP, M_WAITOK | M_ZERO);
  505         bcopy(p, *tok, len);
  506         return (0);
  507 }
  508 
  509 static void
  510 parse_dir_ask_printenv(const char *var)
  511 {
  512         char *val;
  513 
  514         val = kern_getenv(var);
  515         if (val != NULL) {
  516                 printf("  %s=%s\n", var, val);
  517                 freeenv(val);
  518         }
  519 }
  520 
  521 static int
  522 parse_dir_ask(char **conf)
  523 {
  524         char name[80];
  525         char *mnt;
  526         int error;
  527 
  528         vfs_mountroot_wait();
  529 
  530         printf("\nLoader variables:\n");
  531         parse_dir_ask_printenv("vfs.root.mountfrom");
  532         parse_dir_ask_printenv("vfs.root.mountfrom.options");
  533 
  534         printf("\nManual root filesystem specification:\n");
  535         printf("  <fstype>:<device> [options]\n");
  536         printf("      Mount <device> using filesystem <fstype>\n");
  537         printf("      and with the specified (optional) option list.\n");
  538         printf("\n");
  539         printf("    eg. ufs:/dev/da0s1a\n");
  540         printf("        zfs:zroot/ROOT/default\n");
  541         printf("        cd9660:/dev/cd0 ro\n");
  542         printf("          (which is equivalent to: ");
  543         printf("mount -t cd9660 -o ro /dev/cd0 /)\n");
  544         printf("\n");
  545         printf("  ?               List valid disk boot devices\n");
  546         printf("  .               Yield 1 second (for background tasks)\n");
  547         printf("  <empty line>    Abort manual input\n");
  548 
  549         do {
  550                 error = EINVAL;
  551                 printf("\nmountroot> ");
  552                 cngets(name, sizeof(name), GETS_ECHO);
  553                 if (name[0] == '\0')
  554                         break;
  555                 if (name[0] == '?' && name[1] == '\0') {
  556                         printf("\nList of GEOM managed disk devices:\n  ");
  557                         g_dev_print();
  558                         continue;
  559                 }
  560                 if (name[0] == '.' && name[1] == '\0') {
  561                         pause("rmask", hz);
  562                         continue;
  563                 }
  564                 mnt = name;
  565                 error = parse_mount(&mnt);
  566                 if (error == -1)
  567                         printf("Invalid file system specification.\n");
  568         } while (error != 0);
  569 
  570         return (error);
  571 }
  572 
  573 static int
  574 parse_dir_md(char **conf)
  575 {
  576         struct stat sb;
  577         struct thread *td;
  578         struct md_ioctl *mdio;
  579         char *path, *tok;
  580         int error, fd, len;
  581 
  582         td = curthread;
  583 
  584         error = parse_token(conf, &tok);
  585         if (error)
  586                 return (error);
  587 
  588         len = strlen(tok);
  589         mdio = malloc(sizeof(*mdio) + len + 1, M_TEMP, M_WAITOK | M_ZERO);
  590         path = (void *)(mdio + 1);
  591         bcopy(tok, path, len);
  592         free(tok, M_TEMP);
  593 
  594         /* Get file status. */
  595         error = kern_statat(td, 0, AT_FDCWD, path, UIO_SYSSPACE, &sb, NULL);
  596         if (error)
  597                 goto out;
  598 
  599         /* Open /dev/mdctl so that we can attach/detach. */
  600         error = kern_openat(td, AT_FDCWD, "/dev/" MDCTL_NAME, UIO_SYSSPACE,
  601             O_RDWR, 0);
  602         if (error)
  603                 goto out;
  604 
  605         fd = td->td_retval[0];
  606         mdio->md_version = MDIOVERSION;
  607         mdio->md_type = MD_VNODE;
  608 
  609         if (root_mount_mddev != -1) {
  610                 mdio->md_unit = root_mount_mddev;
  611                 (void)kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
  612                 /* Ignore errors. We don't care. */
  613                 root_mount_mddev = -1;
  614         }
  615 
  616         mdio->md_file = (void *)(mdio + 1);
  617         mdio->md_options = MD_AUTOUNIT | MD_READONLY;
  618         mdio->md_mediasize = sb.st_size;
  619         mdio->md_unit = 0;
  620         error = kern_ioctl(td, fd, MDIOCATTACH, (void *)mdio);
  621         if (error)
  622                 goto out;
  623 
  624         if (mdio->md_unit > 9) {
  625                 printf("rootmount: too many md units\n");
  626                 mdio->md_file = NULL;
  627                 mdio->md_options = 0;
  628                 mdio->md_mediasize = 0;
  629                 error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
  630                 /* Ignore errors. We don't care. */
  631                 error = ERANGE;
  632                 goto out;
  633         }
  634 
  635         root_mount_mddev = mdio->md_unit;
  636         printf(MD_NAME "%u attached to %s\n", root_mount_mddev, mdio->md_file);
  637 
  638         error = kern_close(td, fd);
  639 
  640  out:
  641         free(mdio, M_TEMP);
  642         return (error);
  643 }
  644 
  645 static int
  646 parse_dir_onfail(char **conf)
  647 {
  648         char *action;
  649         int error;
  650 
  651         error = parse_token(conf, &action);
  652         if (error)
  653                 return (error);
  654 
  655         if (!strcmp(action, "continue"))
  656                 root_mount_onfail = A_CONTINUE;
  657         else if (!strcmp(action, "panic"))
  658                 root_mount_onfail = A_PANIC;
  659         else if (!strcmp(action, "reboot"))
  660                 root_mount_onfail = A_REBOOT;
  661         else if (!strcmp(action, "retry"))
  662                 root_mount_onfail = A_RETRY;
  663         else {
  664                 printf("rootmount: %s: unknown action\n", action);
  665                 error = EINVAL;
  666         }
  667 
  668         free(action, M_TEMP);
  669         return (0);
  670 }
  671 
  672 static int
  673 parse_dir_timeout(char **conf)
  674 {
  675         char *tok, *endtok;
  676         long secs;
  677         int error;
  678 
  679         error = parse_token(conf, &tok);
  680         if (error)
  681                 return (error);
  682 
  683         secs = strtol(tok, &endtok, 0);
  684         error = (secs < 0 || *endtok != '\0') ? EINVAL : 0;
  685         if (!error)
  686                 root_mount_timeout = secs;
  687         free(tok, M_TEMP);
  688         return (error);
  689 }
  690 
  691 static int
  692 parse_directive(char **conf)
  693 {
  694         char *dir;
  695         int error;
  696 
  697         error = parse_token(conf, &dir);
  698         if (error)
  699                 return (error);
  700 
  701         if (strcmp(dir, ".ask") == 0)
  702                 error = parse_dir_ask(conf);
  703         else if (strcmp(dir, ".md") == 0)
  704                 error = parse_dir_md(conf);
  705         else if (strcmp(dir, ".onfail") == 0)
  706                 error = parse_dir_onfail(conf);
  707         else if (strcmp(dir, ".timeout") == 0)
  708                 error = parse_dir_timeout(conf);
  709         else {
  710                 printf("mountroot: invalid directive `%s'\n", dir);
  711                 /* Ignore the rest of the line. */
  712                 (void)parse_skipto(conf, '\n');
  713                 error = EINVAL;
  714         }
  715         free(dir, M_TEMP);
  716         return (error);
  717 }
  718 
  719 static int
  720 parse_mount_dev_present(const char *dev)
  721 {
  722         struct nameidata nd;
  723         int error;
  724 
  725         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, dev, curthread);
  726         error = namei(&nd);
  727         if (!error)
  728                 vput(nd.ni_vp);
  729         NDFREE(&nd, NDF_ONLY_PNBUF);
  730         return (error != 0) ? 0 : 1;
  731 }
  732 
  733 #define ERRMSGL 255
  734 static int
  735 parse_mount(char **conf)
  736 {
  737         char *errmsg;
  738         struct mntarg *ma;
  739         char *dev, *fs, *opts, *tok;
  740         int delay, error, timeout;
  741 
  742         error = parse_token(conf, &tok);
  743         if (error)
  744                 return (error);
  745         fs = tok;
  746         error = parse_skipto(&tok, ':');
  747         if (error) {
  748                 free(fs, M_TEMP);
  749                 return (error);
  750         }
  751         parse_poke(&tok, '\0');
  752         parse_advance(&tok);
  753         dev = tok;
  754 
  755         if (root_mount_mddev != -1) {
  756                 /* Handle substitution for the md unit number. */
  757                 tok = strstr(dev, "md#");
  758                 if (tok != NULL)
  759                         tok[2] = '' + root_mount_mddev;
  760         }
  761 
  762         /* Parse options. */
  763         error = parse_token(conf, &tok);
  764         opts = (error == 0) ? tok : NULL;
  765 
  766         printf("Trying to mount root from %s:%s [%s]...\n", fs, dev,
  767             (opts != NULL) ? opts : "");
  768 
  769         errmsg = malloc(ERRMSGL, M_TEMP, M_WAITOK | M_ZERO);
  770 
  771         if (vfs_byname(fs) == NULL) {
  772                 strlcpy(errmsg, "unknown file system", ERRMSGL);
  773                 error = ENOENT;
  774                 goto out;
  775         }
  776 
  777         error = vfs_mountroot_wait_if_neccessary(fs, dev);
  778         if (error != 0)
  779                 goto out;
  780 
  781         delay = hz / 10;
  782         timeout = root_mount_timeout * hz;
  783 
  784         for (;;) {
  785                 ma = NULL;
  786                 ma = mount_arg(ma, "fstype", fs, -1);
  787                 ma = mount_arg(ma, "fspath", "/", -1);
  788                 ma = mount_arg(ma, "from", dev, -1);
  789                 ma = mount_arg(ma, "errmsg", errmsg, ERRMSGL);
  790                 ma = mount_arg(ma, "ro", NULL, 0);
  791                 ma = parse_mountroot_options(ma, opts);
  792 
  793                 error = kernel_mount(ma, MNT_ROOTFS);
  794                 if (error == 0 || timeout <= 0)
  795                         break;
  796 
  797                 if (root_mount_timeout * hz == timeout ||
  798                     (bootverbose && timeout % hz == 0)) {
  799                         printf("Mounting from %s:%s failed with error %d; "
  800                             "retrying for %d more second%s\n", fs, dev, error,
  801                             timeout / hz, (timeout / hz > 1) ? "s" : "");
  802                 }
  803                 pause("rmretry", delay);
  804                 timeout -= delay;
  805         }
  806  out:
  807         if (error) {
  808                 printf("Mounting from %s:%s failed with error %d",
  809                     fs, dev, error);
  810                 if (errmsg[0] != '\0')
  811                         printf(": %s", errmsg);
  812                 printf(".\n");
  813         }
  814         free(fs, M_TEMP);
  815         free(errmsg, M_TEMP);
  816         if (opts != NULL)
  817                 free(opts, M_TEMP);
  818         /* kernel_mount can return -1 on error. */
  819         return ((error < 0) ? EDOOFUS : error);
  820 }
  821 #undef ERRMSGL
  822 
  823 static int
  824 vfs_mountroot_parse(struct sbuf *sb, struct mount *mpdevfs)
  825 {
  826         struct mount *mp;
  827         char *conf;
  828         int error;
  829 
  830         root_mount_mddev = -1;
  831 
  832 retry:
  833         conf = sbuf_data(sb);
  834         mp = TAILQ_NEXT(mpdevfs, mnt_list);
  835         error = (mp == NULL) ? 0 : EDOOFUS;
  836         root_mount_onfail = A_CONTINUE;
  837         while (mp == NULL) {
  838                 error = parse_skipto(&conf, CC_NONWHITESPACE);
  839                 if (error == PE_EOL) {
  840                         parse_advance(&conf);
  841                         continue;
  842                 }
  843                 if (error < 0)
  844                         break;
  845                 switch (parse_peek(&conf)) {
  846                 case '#':
  847                         error = parse_skipto(&conf, '\n');
  848                         break;
  849                 case '.':
  850                         error = parse_directive(&conf);
  851                         break;
  852                 default:
  853                         error = parse_mount(&conf);
  854                         if (error == -1) {
  855                                 printf("mountroot: invalid file system "
  856                                     "specification.\n");
  857                                 error = 0;
  858                         }
  859                         break;
  860                 }
  861                 if (error < 0)
  862                         break;
  863                 /* Ignore any trailing garbage on the line. */
  864                 if (parse_peek(&conf) != '\n') {
  865                         printf("mountroot: advancing to next directive...\n");
  866                         (void)parse_skipto(&conf, '\n');
  867                 }
  868                 mp = TAILQ_NEXT(mpdevfs, mnt_list);
  869         }
  870         if (mp != NULL)
  871                 return (0);
  872 
  873         /*
  874          * We failed to mount (a new) root.
  875          */
  876         switch (root_mount_onfail) {
  877         case A_CONTINUE:
  878                 break;
  879         case A_PANIC:
  880                 panic("mountroot: unable to (re-)mount root.");
  881                 /* NOTREACHED */
  882         case A_RETRY:
  883                 goto retry;
  884         case A_REBOOT:
  885                 kern_reboot(RB_NOSYNC);
  886                 /* NOTREACHED */
  887         }
  888 
  889         return (error);
  890 }
  891 
  892 static void
  893 vfs_mountroot_conf0(struct sbuf *sb)
  894 {
  895         char *s, *tok, *mnt, *opt;
  896         int error;
  897 
  898         sbuf_printf(sb, ".onfail panic\n");
  899         sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
  900         if (boothowto & RB_ASKNAME)
  901                 sbuf_printf(sb, ".ask\n");
  902 #ifdef ROOTDEVNAME
  903         if (boothowto & RB_DFLTROOT)
  904                 sbuf_printf(sb, "%s\n", ROOTDEVNAME);
  905 #endif
  906         if (boothowto & RB_CDROM) {
  907                 sbuf_printf(sb, "cd9660:/dev/cd0 ro\n");
  908                 sbuf_printf(sb, ".timeout 0\n");
  909                 sbuf_printf(sb, "cd9660:/dev/cd1 ro\n");
  910                 sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
  911         }
  912         s = kern_getenv("vfs.root.mountfrom");
  913         if (s != NULL) {
  914                 opt = kern_getenv("vfs.root.mountfrom.options");
  915                 tok = s;
  916                 error = parse_token(&tok, &mnt);
  917                 while (!error) {
  918                         sbuf_printf(sb, "%s %s\n", mnt,
  919                             (opt != NULL) ? opt : "");
  920                         free(mnt, M_TEMP);
  921                         error = parse_token(&tok, &mnt);
  922                 }
  923                 if (opt != NULL)
  924                         freeenv(opt);
  925                 freeenv(s);
  926         }
  927         if (rootdevnames[0] != NULL)
  928                 sbuf_printf(sb, "%s\n", rootdevnames[0]);
  929         if (rootdevnames[1] != NULL)
  930                 sbuf_printf(sb, "%s\n", rootdevnames[1]);
  931 #ifdef ROOTDEVNAME
  932         if (!(boothowto & RB_DFLTROOT))
  933                 sbuf_printf(sb, "%s\n", ROOTDEVNAME);
  934 #endif
  935         if (!(boothowto & RB_ASKNAME))
  936                 sbuf_printf(sb, ".ask\n");
  937 }
  938 
  939 static int
  940 vfs_mountroot_readconf(struct thread *td, struct sbuf *sb)
  941 {
  942         static char buf[128];
  943         struct nameidata nd;
  944         off_t ofs;
  945         ssize_t resid;
  946         int error, flags, len;
  947 
  948         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/.mount.conf", td);
  949         flags = FREAD;
  950         error = vn_open(&nd, &flags, 0, NULL);
  951         if (error)
  952                 return (error);
  953 
  954         NDFREE(&nd, NDF_ONLY_PNBUF);
  955         ofs = 0;
  956         len = sizeof(buf) - 1;
  957         while (1) {
  958                 error = vn_rdwr(UIO_READ, nd.ni_vp, buf, len, ofs,
  959                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  960                     NOCRED, &resid, td);
  961                 if (error)
  962                         break;
  963                 if (resid == len)
  964                         break;
  965                 buf[len - resid] = 0;
  966                 sbuf_printf(sb, "%s", buf);
  967                 ofs += len - resid;
  968         }
  969 
  970         VOP_UNLOCK(nd.ni_vp);
  971         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  972         return (error);
  973 }
  974 
  975 static void
  976 vfs_mountroot_wait(void)
  977 {
  978         struct root_hold_token *h;
  979         struct timeval lastfail;
  980         int curfail;
  981 
  982         TSENTER();
  983 
  984         curfail = 0;
  985         while (1) {
  986                 g_waitidle();
  987                 mtx_lock(&root_holds_mtx);
  988                 if (TAILQ_EMPTY(&root_holds)) {
  989                         mtx_unlock(&root_holds_mtx);
  990                         break;
  991                 }
  992                 if (ppsratecheck(&lastfail, &curfail, 1)) {
  993                         printf("Root mount waiting for:");
  994                         TAILQ_FOREACH(h, &root_holds, list)
  995                                 printf(" %s", h->who);
  996                         printf("\n");
  997                 }
  998                 TSWAIT("root mount");
  999                 msleep(&root_holds, &root_holds_mtx, PZERO | PDROP, "roothold",
 1000                     hz);
 1001                 TSUNWAIT("root mount");
 1002         }
 1003 
 1004         TSEXIT();
 1005 }
 1006 
 1007 static int
 1008 vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev)
 1009 {
 1010         int delay, timeout;
 1011 
 1012         /*
 1013          * In case of ZFS and NFS we don't have a way to wait for
 1014          * specific device.  Also do the wait if the user forced that
 1015          * behaviour by setting vfs.root_mount_always_wait=1.
 1016          */
 1017         if (strcmp(fs, "zfs") == 0 || strstr(fs, "nfs") != NULL ||
 1018             dev[0] == '\0' || root_mount_always_wait != 0) {
 1019                 vfs_mountroot_wait();
 1020                 return (0);
 1021         }
 1022 
 1023         /*
 1024          * Otherwise, no point in waiting if the device is already there.
 1025          * Note that we must wait for GEOM to finish reconfiguring itself,
 1026          * eg for geom_part(4) to finish tasting.
 1027          */
 1028         g_waitidle();
 1029         if (parse_mount_dev_present(dev))
 1030                 return (0);
 1031 
 1032         /*
 1033          * No luck.  Let's wait.  This code looks weird, but it's that way
 1034          * to behave exactly as it used to work before.
 1035          */
 1036         vfs_mountroot_wait();
 1037         printf("mountroot: waiting for device %s...\n", dev);
 1038         delay = hz / 10;
 1039         timeout = root_mount_timeout * hz;
 1040         do {
 1041                 pause("rmdev", delay);
 1042                 timeout -= delay;
 1043         } while (timeout > 0 && !parse_mount_dev_present(dev));
 1044 
 1045         if (timeout <= 0)
 1046                 return (ENODEV);
 1047 
 1048         return (0);
 1049 }
 1050 
 1051 void
 1052 vfs_mountroot(void)
 1053 {
 1054         struct mount *mp;
 1055         struct sbuf *sb;
 1056         struct thread *td;
 1057         time_t timebase;
 1058         int error;
 1059 
 1060         mtx_assert(&Giant, MA_NOTOWNED);
 1061 
 1062         TSENTER();
 1063 
 1064         td = curthread;
 1065 
 1066         sb = sbuf_new_auto();
 1067         vfs_mountroot_conf0(sb);
 1068         sbuf_finish(sb);
 1069 
 1070         error = vfs_mountroot_devfs(td, &mp);
 1071         while (!error) {
 1072                 error = vfs_mountroot_parse(sb, mp);
 1073                 if (!error) {
 1074                         vfs_mountroot_shuffle(td, mp);
 1075                         sbuf_clear(sb);
 1076                         error = vfs_mountroot_readconf(td, sb);
 1077                         sbuf_finish(sb);
 1078                 }
 1079         }
 1080 
 1081         sbuf_delete(sb);
 1082 
 1083         /*
 1084          * Iterate over all currently mounted file systems and use
 1085          * the time stamp found to check and/or initialize the RTC.
 1086          * Call inittodr() only once and pass it the largest of the
 1087          * timestamps we encounter.
 1088          */
 1089         timebase = 0;
 1090         mtx_lock(&mountlist_mtx);
 1091         mp = TAILQ_FIRST(&mountlist);
 1092         while (mp != NULL) {
 1093                 if (mp->mnt_time > timebase)
 1094                         timebase = mp->mnt_time;
 1095                 mp = TAILQ_NEXT(mp, mnt_list);
 1096         }
 1097         mtx_unlock(&mountlist_mtx);
 1098         inittodr(timebase);
 1099 
 1100         /* Keep prison0's root in sync with the global rootvnode. */
 1101         mtx_lock(&prison0.pr_mtx);
 1102         prison0.pr_root = rootvnode;
 1103         vref(prison0.pr_root);
 1104         mtx_unlock(&prison0.pr_mtx);
 1105 
 1106         mtx_lock(&root_holds_mtx);
 1107         atomic_store_rel_int(&root_mount_complete, 1);
 1108         wakeup(&root_mount_complete);
 1109         mtx_unlock(&root_holds_mtx);
 1110 
 1111         EVENTHANDLER_INVOKE(mountroot);
 1112 
 1113         TSEXIT();
 1114 }
 1115 
 1116 static struct mntarg *
 1117 parse_mountroot_options(struct mntarg *ma, const char *options)
 1118 {
 1119         char *p;
 1120         char *name, *name_arg;
 1121         char *val, *val_arg;
 1122         char *opts;
 1123 
 1124         if (options == NULL || options[0] == '\0')
 1125                 return (ma);
 1126 
 1127         p = opts = strdup(options, M_MOUNT);
 1128         if (opts == NULL) {
 1129                 return (ma);
 1130         }
 1131 
 1132         while((name = strsep(&p, ",")) != NULL) {
 1133                 if (name[0] == '\0')
 1134                         break;
 1135 
 1136                 val = strchr(name, '=');
 1137                 if (val != NULL) {
 1138                         *val = '\0';
 1139                         ++val;
 1140                 }
 1141                 if( strcmp(name, "rw") == 0 ||
 1142                     strcmp(name, "noro") == 0) {
 1143                         /*
 1144                          * The first time we mount the root file system,
 1145                          * we need to mount 'ro', so We need to ignore
 1146                          * 'rw' and 'noro' mount options.
 1147                          */
 1148                         continue;
 1149                 }
 1150                 name_arg = strdup(name, M_MOUNT);
 1151                 val_arg = NULL;
 1152                 if (val != NULL)
 1153                         val_arg = strdup(val, M_MOUNT);
 1154 
 1155                 ma = mount_arg(ma, name_arg, val_arg,
 1156                     (val_arg != NULL ? -1 : 0));
 1157         }
 1158         free(opts, M_MOUNT);
 1159         return (ma);
 1160 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/vfs_mountroot.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_mountroot.c
