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/fcntl.h>
   49 #include <sys/jail.h>
   50 #include <sys/kernel.h>
   51 #include <sys/malloc.h>
   52 #include <sys/mdioctl.h>
   53 #include <sys/mount.h>
   54 #include <sys/mutex.h>
   55 #include <sys/namei.h>
   56 #include <sys/priv.h>
   57 #include <sys/proc.h>
   58 #include <sys/filedesc.h>
   59 #include <sys/reboot.h>
   60 #include <sys/sbuf.h>
   61 #include <sys/stat.h>
   62 #include <sys/syscallsubr.h>
   63 #include <sys/sysproto.h>
   64 #include <sys/sx.h>
   65 #include <sys/sysctl.h>
   66 #include <sys/sysent.h>
   67 #include <sys/systm.h>
   68 #include <sys/vnode.h>
   69 
   70 #include <geom/geom.h>
   71 
   72 /*
   73  * The root filesystem is detailed in the kernel environment variable
   74  * vfs.root.mountfrom, which is expected to be in the general format
   75  *
   76  * <vfsname>:[<path>][  <vfsname>:[<path>] ...]
   77  * vfsname   := the name of a VFS known to the kernel and capable
   78  *              of being mounted as root
   79  * path      := disk device name or other data used by the filesystem
   80  *              to locate its physical store
   81  *
   82  * If the environment variable vfs.root.mountfrom is a space separated list,
   83  * each list element is tried in turn and the root filesystem will be mounted
   84  * from the first one that succeeds.
   85  *
   86  * The environment variable vfs.root.mountfrom.options is a comma delimited
   87  * set of string mount options.  These mount options must be parseable
   88  * by nmount() in the kernel.
   89  */
   90 
   91 static int parse_mount(char **);
   92 static struct mntarg *parse_mountroot_options(struct mntarg *, const char *);
   93 static int sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS);
   94 static void vfs_mountroot_wait(void);
   95 static int vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev);
   96 
   97 /*
   98  * The vnode of the system's root (/ in the filesystem, without chroot
   99  * active.)
  100  */
  101 struct vnode *rootvnode;
  102 
  103 /*
  104  * Mount of the system's /dev.
  105  */
  106 struct mount *rootdevmp;
  107 
  108 char *rootdevnames[2] = {NULL, NULL};
  109 
  110 struct mtx root_holds_mtx;
  111 MTX_SYSINIT(root_holds, &root_holds_mtx, "root_holds", MTX_DEF);
  112 
  113 static TAILQ_HEAD(, root_hold_token)    root_holds =
  114     TAILQ_HEAD_INITIALIZER(root_holds);
  115 
  116 enum action {
  117         A_CONTINUE,
  118         A_PANIC,
  119         A_REBOOT,
  120         A_RETRY
  121 };
  122 
  123 enum rh_flags {
  124         RH_FREE,
  125         RH_ALLOC,
  126         RH_ARG,
  127 };
  128 
  129 static enum action root_mount_onfail = A_CONTINUE;
  130 
  131 static int root_mount_mddev;
  132 static int root_mount_complete;
  133 
  134 /* By default wait up to 3 seconds for devices to appear. */
  135 static int root_mount_timeout = 3;
  136 TUNABLE_INT("vfs.mountroot.timeout", &root_mount_timeout);
  137 
  138 static int root_mount_always_wait = 0;
  139 SYSCTL_INT(_vfs, OID_AUTO, root_mount_always_wait, CTLFLAG_RDTUN,
  140     &root_mount_always_wait, 0,
  141     "Wait for root mount holds even if the root device already exists");
  142 
  143 SYSCTL_PROC(_vfs, OID_AUTO, root_mount_hold,
  144     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
  145     NULL, 0, sysctl_vfs_root_mount_hold, "A",
  146     "List of root mount hold tokens");
  147 
  148 static int
  149 sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS)
  150 {
  151         struct sbuf sb;
  152         struct root_hold_token *h;
  153         int error;
  154 
  155         sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
  156 
  157         mtx_lock(&root_holds_mtx);
  158         TAILQ_FOREACH(h, &root_holds, list) {
  159                 if (h != TAILQ_FIRST(&root_holds))
  160                         sbuf_putc(&sb, ' ');
  161                 sbuf_printf(&sb, "%s", h->who);
  162         }
  163         mtx_unlock(&root_holds_mtx);
  164 
  165         error = sbuf_finish(&sb);
  166         if (error == 0)
  167                 error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
  168         sbuf_delete(&sb);
  169         return (error);
  170 }
  171 
  172 struct root_hold_token *
  173 root_mount_hold(const char *identifier)
  174 {
  175         struct root_hold_token *h;
  176 
  177         h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
  178         h->flags = RH_ALLOC;
  179         h->who = identifier;
  180         mtx_lock(&root_holds_mtx);
  181         TSHOLD("root mount");
  182         TAILQ_INSERT_TAIL(&root_holds, h, list);
  183         mtx_unlock(&root_holds_mtx);
  184         return (h);
  185 }
  186 
  187 void
  188 root_mount_hold_token(const char *identifier, struct root_hold_token *h)
  189 {
  190 #ifdef INVARIANTS
  191         struct root_hold_token *t;
  192 #endif
  193 
  194         h->flags = RH_ARG;
  195         h->who = identifier;
  196         mtx_lock(&root_holds_mtx);
  197 #ifdef INVARIANTS
  198         TAILQ_FOREACH(t, &root_holds, list) {
  199                 if (t == h) {
  200                         panic("Duplicate mount hold by '%s' on %p",
  201                             identifier, h);
  202                 }
  203         }
  204 #endif
  205         TSHOLD("root mount");
  206         TAILQ_INSERT_TAIL(&root_holds, h, list);
  207         mtx_unlock(&root_holds_mtx);
  208 }
  209 
  210 void
  211 root_mount_rel(struct root_hold_token *h)
  212 {
  213 
  214         if (h == NULL || h->flags == RH_FREE)
  215                 return;
  216 
  217         mtx_lock(&root_holds_mtx);
  218         TAILQ_REMOVE(&root_holds, h, list);
  219         TSRELEASE("root mount");
  220         wakeup(&root_holds);
  221         mtx_unlock(&root_holds_mtx);
  222         if (h->flags == RH_ALLOC) {
  223                 free(h, M_DEVBUF);
  224         } else
  225                 h->flags = RH_FREE;
  226 }
  227 
  228 int
  229 root_mounted(void)
  230 {
  231 
  232         /* No mutex is acquired here because int stores are atomic. */
  233         return (root_mount_complete);
  234 }
  235 
  236 static void
  237 set_rootvnode(void)
  238 {
  239         struct proc *p;
  240 
  241         if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
  242                 panic("Cannot find root vnode");
  243 
  244         VOP_UNLOCK(rootvnode, 0);
  245 
  246         p = curthread->td_proc;
  247         FILEDESC_XLOCK(p->p_fd);
  248 
  249         if (p->p_fd->fd_cdir != NULL)
  250                 vrele(p->p_fd->fd_cdir);
  251         p->p_fd->fd_cdir = rootvnode;
  252         VREF(rootvnode);
  253 
  254         if (p->p_fd->fd_rdir != NULL)
  255                 vrele(p->p_fd->fd_rdir);
  256         p->p_fd->fd_rdir = rootvnode;
  257         VREF(rootvnode);
  258 
  259         FILEDESC_XUNLOCK(p->p_fd);
  260 }
  261 
  262 static int
  263 vfs_mountroot_devfs(struct thread *td, struct mount **mpp)
  264 {
  265         struct vfsoptlist *opts;
  266         struct vfsconf *vfsp;
  267         struct mount *mp;
  268         int error;
  269 
  270         *mpp = NULL;
  271 
  272         if (rootdevmp != NULL) {
  273                 /*
  274                  * Already have /dev; this happens during rerooting.
  275                  */
  276                 error = vfs_busy(rootdevmp, 0);
  277                 if (error != 0)
  278                         return (error);
  279                 *mpp = rootdevmp;
  280         } else {
  281                 vfsp = vfs_byname("devfs");
  282                 KASSERT(vfsp != NULL, ("Could not find devfs by name"));
  283                 if (vfsp == NULL)
  284                         return (ENOENT);
  285 
  286                 mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
  287 
  288                 error = VFS_MOUNT(mp);
  289                 KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
  290                 if (error)
  291                         return (error);
  292 
  293                 error = VFS_STATFS(mp, &mp->mnt_stat);
  294                 KASSERT(error == 0, ("VFS_STATFS(devfs) failed %d", error));
  295                 if (error)
  296                         return (error);
  297 
  298                 opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
  299                 TAILQ_INIT(opts);
  300                 mp->mnt_opt = opts;
  301 
  302                 mtx_lock(&mountlist_mtx);
  303                 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
  304                 mtx_unlock(&mountlist_mtx);
  305 
  306                 *mpp = mp;
  307                 rootdevmp = mp;
  308         }
  309 
  310         set_rootvnode();
  311 
  312         error = kern_symlinkat(td, "/", AT_FDCWD, "dev", UIO_SYSSPACE);
  313         if (error)
  314                 printf("kern_symlink /dev -> / returns %d\n", error);
  315 
  316         return (error);
  317 }
  318 
  319 static void
  320 vfs_mountroot_shuffle(struct thread *td, struct mount *mpdevfs)
  321 {
  322         struct nameidata nd;
  323         struct mount *mporoot, *mpnroot;
  324         struct vnode *vp, *vporoot, *vpdevfs;
  325         char *fspath;
  326         int error;
  327 
  328         mpnroot = TAILQ_NEXT(mpdevfs, mnt_list);
  329 
  330         /* Shuffle the mountlist. */
  331         mtx_lock(&mountlist_mtx);
  332         mporoot = TAILQ_FIRST(&mountlist);
  333         TAILQ_REMOVE(&mountlist, mpdevfs, mnt_list);
  334         if (mporoot != mpdevfs) {
  335                 TAILQ_REMOVE(&mountlist, mpnroot, mnt_list);
  336                 TAILQ_INSERT_HEAD(&mountlist, mpnroot, mnt_list);
  337         }
  338         TAILQ_INSERT_TAIL(&mountlist, mpdevfs, mnt_list);
  339         mtx_unlock(&mountlist_mtx);
  340 
  341         cache_purgevfs(mporoot, true);
  342         if (mporoot != mpdevfs)
  343                 cache_purgevfs(mpdevfs, true);
  344 
  345         VFS_ROOT(mporoot, LK_EXCLUSIVE, &vporoot);
  346 
  347         VI_LOCK(vporoot);
  348         vporoot->v_iflag &= ~VI_MOUNT;
  349         VI_UNLOCK(vporoot);
  350         vporoot->v_mountedhere = NULL;
  351         mporoot->mnt_flag &= ~MNT_ROOTFS;
  352         mporoot->mnt_vnodecovered = NULL;
  353         vput(vporoot);
  354 
  355         /* Set up the new rootvnode, and purge the cache */
  356         mpnroot->mnt_vnodecovered = NULL;
  357         set_rootvnode();
  358         cache_purgevfs(rootvnode->v_mount, true);
  359 
  360         if (mporoot != mpdevfs) {
  361                 /* Remount old root under /.mount or /mnt */
  362                 fspath = "/.mount";
  363                 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  364                     fspath, td);
  365                 error = namei(&nd);
  366                 if (error) {
  367                         NDFREE(&nd, NDF_ONLY_PNBUF);
  368                         fspath = "/mnt";
  369                         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  370                             fspath, td);
  371                         error = namei(&nd);
  372                 }
  373                 if (!error) {
  374                         vp = nd.ni_vp;
  375                         error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
  376                         if (!error)
  377                                 error = vinvalbuf(vp, V_SAVE, 0, 0);
  378                         if (!error) {
  379                                 cache_purge(vp);
  380                                 mporoot->mnt_vnodecovered = vp;
  381                                 vp->v_mountedhere = mporoot;
  382                                 strlcpy(mporoot->mnt_stat.f_mntonname,
  383                                     fspath, MNAMELEN);
  384                                 VOP_UNLOCK(vp, 0);
  385                         } else
  386                                 vput(vp);
  387                 }
  388                 NDFREE(&nd, NDF_ONLY_PNBUF);
  389 
  390                 if (error)
  391                         printf("mountroot: unable to remount previous root "
  392                             "under /.mount or /mnt (error %d)\n", error);
  393         }
  394 
  395         /* Remount devfs under /dev */
  396         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
  397         error = namei(&nd);
  398         if (!error) {
  399                 vp = nd.ni_vp;
  400                 error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
  401                 if (!error)
  402                         error = vinvalbuf(vp, V_SAVE, 0, 0);
  403                 if (!error) {
  404                         vpdevfs = mpdevfs->mnt_vnodecovered;
  405                         if (vpdevfs != NULL) {
  406                                 cache_purge(vpdevfs);
  407                                 vpdevfs->v_mountedhere = NULL;
  408                                 vrele(vpdevfs);
  409                         }
  410                         mpdevfs->mnt_vnodecovered = vp;
  411                         vp->v_mountedhere = mpdevfs;
  412                         VOP_UNLOCK(vp, 0);
  413                 } else
  414                         vput(vp);
  415         }
  416         if (error)
  417                 printf("mountroot: unable to remount devfs under /dev "
  418                     "(error %d)\n", error);
  419         NDFREE(&nd, NDF_ONLY_PNBUF);
  420 
  421         if (mporoot == mpdevfs) {
  422                 vfs_unbusy(mpdevfs);
  423                 /* Unlink the no longer needed /dev/dev -> / symlink */
  424                 error = kern_unlinkat(td, AT_FDCWD, "/dev/dev",
  425                     UIO_SYSSPACE, 0, 0);
  426                 if (error)
  427                         printf("mountroot: unable to unlink /dev/dev "
  428                             "(error %d)\n", error);
  429         }
  430 }
  431 
  432 /*
  433  * Configuration parser.
  434  */
  435 
  436 /* Parser character classes. */
  437 #define CC_WHITESPACE           -1
  438 #define CC_NONWHITESPACE        -2
  439 
  440 /* Parse errors. */
  441 #define PE_EOF                  -1
  442 #define PE_EOL                  -2
  443 
  444 static __inline int
  445 parse_peek(char **conf)
  446 {
  447 
  448         return (**conf);
  449 }
  450 
  451 static __inline void
  452 parse_poke(char **conf, int c)
  453 {
  454 
  455         **conf = c;
  456 }
  457 
  458 static __inline void
  459 parse_advance(char **conf)
  460 {
  461 
  462         (*conf)++;
  463 }
  464 
  465 static int
  466 parse_skipto(char **conf, int mc)
  467 {
  468         int c, match;
  469 
  470         while (1) {
  471                 c = parse_peek(conf);
  472                 if (c == 0)
  473                         return (PE_EOF);
  474                 switch (mc) {
  475                 case CC_WHITESPACE:
  476                         match = (c == ' ' || c == '\t' || c == '\n') ? 1 : 0;
  477                         break;
  478                 case CC_NONWHITESPACE:
  479                         if (c == '\n')
  480                                 return (PE_EOL);
  481                         match = (c != ' ' && c != '\t') ? 1 : 0;
  482                         break;
  483                 default:
  484                         match = (c == mc) ? 1 : 0;
  485                         break;
  486                 }
  487                 if (match)
  488                         break;
  489                 parse_advance(conf);
  490         }
  491         return (0);
  492 }
  493 
  494 static int
  495 parse_token(char **conf, char **tok)
  496 {
  497         char *p;
  498         size_t len;
  499         int error;
  500 
  501         *tok = NULL;
  502         error = parse_skipto(conf, CC_NONWHITESPACE);
  503         if (error)
  504                 return (error);
  505         p = *conf;
  506         error = parse_skipto(conf, CC_WHITESPACE);
  507         len = *conf - p;
  508         *tok = malloc(len + 1, M_TEMP, M_WAITOK | M_ZERO);
  509         bcopy(p, *tok, len);
  510         return (0);
  511 }
  512 
  513 static void
  514 parse_dir_ask_printenv(const char *var)
  515 {
  516         char *val;
  517 
  518         val = kern_getenv(var);
  519         if (val != NULL) {
  520                 printf("  %s=%s\n", var, val);
  521                 freeenv(val);
  522         }
  523 }
  524 
  525 static int
  526 parse_dir_ask(char **conf)
  527 {
  528         char name[80];
  529         char *mnt;
  530         int error;
  531 
  532         vfs_mountroot_wait();
  533 
  534         printf("\nLoader variables:\n");
  535         parse_dir_ask_printenv("vfs.root.mountfrom");
  536         parse_dir_ask_printenv("vfs.root.mountfrom.options");
  537 
  538         printf("\nManual root filesystem specification:\n");
  539         printf("  <fstype>:<device> [options]\n");
  540         printf("      Mount <device> using filesystem <fstype>\n");
  541         printf("      and with the specified (optional) option list.\n");
  542         printf("\n");
  543         printf("    eg. ufs:/dev/da0s1a\n");
  544         printf("        zfs:zroot/ROOT/default\n");
  545         printf("        cd9660:/dev/cd0 ro\n");
  546         printf("          (which is equivalent to: ");
  547         printf("mount -t cd9660 -o ro /dev/cd0 /)\n");
  548         printf("\n");
  549         printf("  ?               List valid disk boot devices\n");
  550         printf("  .               Yield 1 second (for background tasks)\n");
  551         printf("  <empty line>    Abort manual input\n");
  552 
  553         do {
  554                 error = EINVAL;
  555                 printf("\nmountroot> ");
  556                 cngets(name, sizeof(name), GETS_ECHO);
  557                 if (name[0] == '\0')
  558                         break;
  559                 if (name[0] == '?' && name[1] == '\0') {
  560                         printf("\nList of GEOM managed disk devices:\n  ");
  561                         g_dev_print();
  562                         continue;
  563                 }
  564                 if (name[0] == '.' && name[1] == '\0') {
  565                         pause("rmask", hz);
  566                         continue;
  567                 }
  568                 mnt = name;
  569                 error = parse_mount(&mnt);
  570                 if (error == -1)
  571                         printf("Invalid file system specification.\n");
  572         } while (error != 0);
  573 
  574         return (error);
  575 }
  576 
  577 static int
  578 parse_dir_md(char **conf)
  579 {
  580         struct stat sb;
  581         struct thread *td;
  582         struct md_ioctl *mdio;
  583         char *path, *tok;
  584         int error, fd, len;
  585 
  586         td = curthread;
  587         fd = -1;
  588 
  589         error = parse_token(conf, &tok);
  590         if (error)
  591                 return (error);
  592 
  593         len = strlen(tok);
  594         mdio = malloc(sizeof(*mdio) + len + 1, M_TEMP, M_WAITOK | M_ZERO);
  595         path = (void *)(mdio + 1);
  596         bcopy(tok, path, len);
  597         free(tok, M_TEMP);
  598 
  599         /* Get file status. */
  600         error = kern_statat(td, 0, AT_FDCWD, path, UIO_SYSSPACE, &sb, NULL);
  601         if (error)
  602                 goto out;
  603 
  604         /* Open /dev/mdctl so that we can attach/detach. */
  605         error = kern_openat(td, AT_FDCWD, "/dev/" MDCTL_NAME, UIO_SYSSPACE,
  606             O_RDWR, 0);
  607         if (error)
  608                 goto out;
  609 
  610         fd = td->td_retval[0];
  611         mdio->md_version = MDIOVERSION;
  612         mdio->md_type = MD_VNODE;
  613 
  614         if (root_mount_mddev != -1) {
  615                 mdio->md_unit = root_mount_mddev;
  616                 (void)kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
  617                 /* Ignore errors. We don't care. */
  618                 root_mount_mddev = -1;
  619         }
  620 
  621         mdio->md_file = (void *)(mdio + 1);
  622         mdio->md_options = MD_AUTOUNIT | MD_READONLY;
  623         mdio->md_mediasize = sb.st_size;
  624         mdio->md_unit = 0;
  625         error = kern_ioctl(td, fd, MDIOCATTACH, (void *)mdio);
  626         if (error)
  627                 goto out;
  628 
  629         if (mdio->md_unit > 9) {
  630                 printf("rootmount: too many md units\n");
  631                 mdio->md_file = NULL;
  632                 mdio->md_options = 0;
  633                 mdio->md_mediasize = 0;
  634                 error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
  635                 /* Ignore errors. We don't care. */
  636                 error = ERANGE;
  637                 goto out;
  638         }
  639 
  640         root_mount_mddev = mdio->md_unit;
  641         printf(MD_NAME "%u attached to %s\n", root_mount_mddev, mdio->md_file);
  642 
  643  out:
  644         if (fd >= 0)
  645                 (void)kern_close(td, fd);
  646         free(mdio, M_TEMP);
  647         return (error);
  648 }
  649 
  650 static int
  651 parse_dir_onfail(char **conf)
  652 {
  653         char *action;
  654         int error;
  655 
  656         error = parse_token(conf, &action);
  657         if (error)
  658                 return (error);
  659 
  660         if (!strcmp(action, "continue"))
  661                 root_mount_onfail = A_CONTINUE;
  662         else if (!strcmp(action, "panic"))
  663                 root_mount_onfail = A_PANIC;
  664         else if (!strcmp(action, "reboot"))
  665                 root_mount_onfail = A_REBOOT;
  666         else if (!strcmp(action, "retry"))
  667                 root_mount_onfail = A_RETRY;
  668         else {
  669                 printf("rootmount: %s: unknown action\n", action);
  670                 error = EINVAL;
  671         }
  672 
  673         free(action, M_TEMP);
  674         return (0);
  675 }
  676 
  677 static int
  678 parse_dir_timeout(char **conf)
  679 {
  680         char *tok, *endtok;
  681         long secs;
  682         int error;
  683 
  684         error = parse_token(conf, &tok);
  685         if (error)
  686                 return (error);
  687 
  688         secs = strtol(tok, &endtok, 0);
  689         error = (secs < 0 || *endtok != '\0') ? EINVAL : 0;
  690         if (!error)
  691                 root_mount_timeout = secs;
  692         free(tok, M_TEMP);
  693         return (error);
  694 }
  695 
  696 static int
  697 parse_directive(char **conf)
  698 {
  699         char *dir;
  700         int error;
  701 
  702         error = parse_token(conf, &dir);
  703         if (error)
  704                 return (error);
  705 
  706         if (strcmp(dir, ".ask") == 0)
  707                 error = parse_dir_ask(conf);
  708         else if (strcmp(dir, ".md") == 0)
  709                 error = parse_dir_md(conf);
  710         else if (strcmp(dir, ".onfail") == 0)
  711                 error = parse_dir_onfail(conf);
  712         else if (strcmp(dir, ".timeout") == 0)
  713                 error = parse_dir_timeout(conf);
  714         else {
  715                 printf("mountroot: invalid directive `%s'\n", dir);
  716                 /* Ignore the rest of the line. */
  717                 (void)parse_skipto(conf, '\n');
  718                 error = EINVAL;
  719         }
  720         free(dir, M_TEMP);
  721         return (error);
  722 }
  723 
  724 static int
  725 parse_mount_dev_present(const char *dev)
  726 {
  727         struct nameidata nd;
  728         int error;
  729 
  730         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, dev, curthread);
  731         error = namei(&nd);
  732         if (!error)
  733                 vput(nd.ni_vp);
  734         NDFREE(&nd, NDF_ONLY_PNBUF);
  735         return (error != 0) ? 0 : 1;
  736 }
  737 
  738 #define ERRMSGL 255
  739 static int
  740 parse_mount(char **conf)
  741 {
  742         char *errmsg;
  743         struct mntarg *ma;
  744         char *dev, *fs, *opts, *tok;
  745         int delay, error, timeout;
  746 
  747         error = parse_token(conf, &tok);
  748         if (error)
  749                 return (error);
  750         fs = tok;
  751         error = parse_skipto(&tok, ':');
  752         if (error) {
  753                 free(fs, M_TEMP);
  754                 return (error);
  755         }
  756         parse_poke(&tok, '\0');
  757         parse_advance(&tok);
  758         dev = tok;
  759 
  760         if (root_mount_mddev != -1) {
  761                 /* Handle substitution for the md unit number. */
  762                 tok = strstr(dev, "md#");
  763                 if (tok != NULL)
  764                         tok[2] = '' + root_mount_mddev;
  765         }
  766 
  767         /* Parse options. */
  768         error = parse_token(conf, &tok);
  769         opts = (error == 0) ? tok : NULL;
  770 
  771         printf("Trying to mount root from %s:%s [%s]...\n", fs, dev,
  772             (opts != NULL) ? opts : "");
  773 
  774         errmsg = malloc(ERRMSGL, M_TEMP, M_WAITOK | M_ZERO);
  775 
  776         if (vfs_byname(fs) == NULL) {
  777                 strlcpy(errmsg, "unknown file system", ERRMSGL);
  778                 error = ENOENT;
  779                 goto out;
  780         }
  781 
  782         error = vfs_mountroot_wait_if_neccessary(fs, dev);
  783         if (error != 0)
  784                 goto out;
  785 
  786         delay = hz / 10;
  787         timeout = root_mount_timeout * hz;
  788 
  789         for (;;) {
  790                 ma = NULL;
  791                 ma = mount_arg(ma, "fstype", fs, -1);
  792                 ma = mount_arg(ma, "fspath", "/", -1);
  793                 ma = mount_arg(ma, "from", dev, -1);
  794                 ma = mount_arg(ma, "errmsg", errmsg, ERRMSGL);
  795                 ma = mount_arg(ma, "ro", NULL, 0);
  796                 ma = parse_mountroot_options(ma, opts);
  797 
  798                 error = kernel_mount(ma, MNT_ROOTFS);
  799                 if (error == 0 || timeout <= 0)
  800                         break;
  801 
  802                 if (root_mount_timeout * hz == timeout ||
  803                     (bootverbose && timeout % hz == 0)) {
  804                         printf("Mounting from %s:%s failed with error %d; "
  805                             "retrying for %d more second%s\n", fs, dev, error,
  806                             timeout / hz, (timeout / hz > 1) ? "s" : "");
  807                 }
  808                 pause("rmretry", delay);
  809                 timeout -= delay;
  810         }
  811  out:
  812         if (error) {
  813                 printf("Mounting from %s:%s failed with error %d",
  814                     fs, dev, error);
  815                 if (errmsg[0] != '\0')
  816                         printf(": %s", errmsg);
  817                 printf(".\n");
  818         }
  819         free(fs, M_TEMP);
  820         free(errmsg, M_TEMP);
  821         if (opts != NULL)
  822                 free(opts, M_TEMP);
  823         /* kernel_mount can return -1 on error. */
  824         return ((error < 0) ? EDOOFUS : error);
  825 }
  826 #undef ERRMSGL
  827 
  828 static int
  829 vfs_mountroot_parse(struct sbuf *sb, struct mount *mpdevfs)
  830 {
  831         struct mount *mp;
  832         char *conf;
  833         int error;
  834 
  835         root_mount_mddev = -1;
  836 
  837 retry:
  838         conf = sbuf_data(sb);
  839         mp = TAILQ_NEXT(mpdevfs, mnt_list);
  840         error = (mp == NULL) ? 0 : EDOOFUS;
  841         root_mount_onfail = A_CONTINUE;
  842         while (mp == NULL) {
  843                 error = parse_skipto(&conf, CC_NONWHITESPACE);
  844                 if (error == PE_EOL) {
  845                         parse_advance(&conf);
  846                         continue;
  847                 }
  848                 if (error < 0)
  849                         break;
  850                 switch (parse_peek(&conf)) {
  851                 case '#':
  852                         error = parse_skipto(&conf, '\n');
  853                         break;
  854                 case '.':
  855                         error = parse_directive(&conf);
  856                         break;
  857                 default:
  858                         error = parse_mount(&conf);
  859                         if (error == -1) {
  860                                 printf("mountroot: invalid file system "
  861                                     "specification.\n");
  862                                 error = 0;
  863                         }
  864                         break;
  865                 }
  866                 if (error < 0)
  867                         break;
  868                 /* Ignore any trailing garbage on the line. */
  869                 if (parse_peek(&conf) != '\n') {
  870                         printf("mountroot: advancing to next directive...\n");
  871                         (void)parse_skipto(&conf, '\n');
  872                 }
  873                 mp = TAILQ_NEXT(mpdevfs, mnt_list);
  874         }
  875         if (mp != NULL)
  876                 return (0);
  877 
  878         /*
  879          * We failed to mount (a new) root.
  880          */
  881         switch (root_mount_onfail) {
  882         case A_CONTINUE:
  883                 break;
  884         case A_PANIC:
  885                 panic("mountroot: unable to (re-)mount root.");
  886                 /* NOTREACHED */
  887         case A_RETRY:
  888                 goto retry;
  889         case A_REBOOT:
  890                 kern_reboot(RB_NOSYNC);
  891                 /* NOTREACHED */
  892         }
  893 
  894         return (error);
  895 }
  896 
  897 static void
  898 vfs_mountroot_conf0(struct sbuf *sb)
  899 {
  900         char *s, *tok, *mnt, *opt;
  901         int error;
  902 
  903         sbuf_printf(sb, ".onfail panic\n");
  904         sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
  905         if (boothowto & RB_ASKNAME)
  906                 sbuf_printf(sb, ".ask\n");
  907 #ifdef ROOTDEVNAME
  908         if (boothowto & RB_DFLTROOT)
  909                 sbuf_printf(sb, "%s\n", ROOTDEVNAME);
  910 #endif
  911         if (boothowto & RB_CDROM) {
  912                 sbuf_printf(sb, "cd9660:/dev/cd0 ro\n");
  913                 sbuf_printf(sb, ".timeout 0\n");
  914                 sbuf_printf(sb, "cd9660:/dev/cd1 ro\n");
  915                 sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
  916         }
  917         s = kern_getenv("vfs.root.mountfrom");
  918         if (s != NULL) {
  919                 opt = kern_getenv("vfs.root.mountfrom.options");
  920                 tok = s;
  921                 error = parse_token(&tok, &mnt);
  922                 while (!error) {
  923                         sbuf_printf(sb, "%s %s\n", mnt,
  924                             (opt != NULL) ? opt : "");
  925                         free(mnt, M_TEMP);
  926                         error = parse_token(&tok, &mnt);
  927                 }
  928                 if (opt != NULL)
  929                         freeenv(opt);
  930                 freeenv(s);
  931         }
  932         if (rootdevnames[0] != NULL)
  933                 sbuf_printf(sb, "%s\n", rootdevnames[0]);
  934         if (rootdevnames[1] != NULL)
  935                 sbuf_printf(sb, "%s\n", rootdevnames[1]);
  936 #ifdef ROOTDEVNAME
  937         if (!(boothowto & RB_DFLTROOT))
  938                 sbuf_printf(sb, "%s\n", ROOTDEVNAME);
  939 #endif
  940         if (!(boothowto & RB_ASKNAME))
  941                 sbuf_printf(sb, ".ask\n");
  942 }
  943 
  944 static int
  945 vfs_mountroot_readconf(struct thread *td, struct sbuf *sb)
  946 {
  947         static char buf[128];
  948         struct nameidata nd;
  949         off_t ofs;
  950         ssize_t resid;
  951         int error, flags, len;
  952 
  953         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/.mount.conf", td);
  954         flags = FREAD;
  955         error = vn_open(&nd, &flags, 0, NULL);
  956         if (error)
  957                 return (error);
  958 
  959         NDFREE(&nd, NDF_ONLY_PNBUF);
  960         ofs = 0;
  961         len = sizeof(buf) - 1;
  962         while (1) {
  963                 error = vn_rdwr(UIO_READ, nd.ni_vp, buf, len, ofs,
  964                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  965                     NOCRED, &resid, td);
  966                 if (error)
  967                         break;
  968                 if (resid == len)
  969                         break;
  970                 buf[len - resid] = 0;
  971                 sbuf_printf(sb, "%s", buf);
  972                 ofs += len - resid;
  973         }
  974 
  975         VOP_UNLOCK(nd.ni_vp, 0);
  976         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  977         return (error);
  978 }
  979 
  980 static void
  981 vfs_mountroot_wait(void)
  982 {
  983         struct root_hold_token *h;
  984         struct timeval lastfail;
  985         int curfail;
  986 
  987         TSENTER();
  988 
  989         curfail = 0;
  990         while (1) {
  991                 g_waitidle();
  992                 mtx_lock(&root_holds_mtx);
  993                 if (TAILQ_EMPTY(&root_holds)) {
  994                         mtx_unlock(&root_holds_mtx);
  995                         break;
  996                 }
  997                 if (ppsratecheck(&lastfail, &curfail, 1)) {
  998                         printf("Root mount waiting for:");
  999                         TAILQ_FOREACH(h, &root_holds, list)
 1000                                 printf(" %s", h->who);
 1001                         printf("\n");
 1002                 }
 1003                 TSWAIT("root mount");
 1004                 msleep(&root_holds, &root_holds_mtx, PZERO | PDROP, "roothold",
 1005                     hz);
 1006                 TSUNWAIT("root mount");
 1007         }
 1008 
 1009         TSEXIT();
 1010 }
 1011 
 1012 static int
 1013 vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev)
 1014 {
 1015         int delay, timeout;
 1016 
 1017         /*
 1018          * In case of ZFS and NFS we don't have a way to wait for
 1019          * specific device.  Also do the wait if the user forced that
 1020          * behaviour by setting vfs.root_mount_always_wait=1.
 1021          */
 1022         if (strcmp(fs, "zfs") == 0 || strstr(fs, "nfs") != NULL ||
 1023             dev[0] == '\0' || root_mount_always_wait != 0) {
 1024                 vfs_mountroot_wait();
 1025                 return (0);
 1026         }
 1027 
 1028         /*
 1029          * Otherwise, no point in waiting if the device is already there.
 1030          * Note that we must wait for GEOM to finish reconfiguring itself,
 1031          * eg for geom_part(4) to finish tasting.
 1032          */
 1033         g_waitidle();
 1034         if (parse_mount_dev_present(dev))
 1035                 return (0);
 1036 
 1037         /*
 1038          * No luck.  Let's wait.  This code looks weird, but it's that way
 1039          * to behave exactly as it used to work before.
 1040          */
 1041         vfs_mountroot_wait();
 1042         printf("mountroot: waiting for device %s...\n", dev);
 1043         delay = hz / 10;
 1044         timeout = root_mount_timeout * hz;
 1045         do {
 1046                 pause("rmdev", delay);
 1047                 timeout -= delay;
 1048         } while (timeout > 0 && !parse_mount_dev_present(dev));
 1049 
 1050         if (timeout <= 0)
 1051                 return (ENODEV);
 1052 
 1053         return (0);
 1054 }
 1055 
 1056 void
 1057 vfs_mountroot(void)
 1058 {
 1059         struct mount *mp;
 1060         struct sbuf *sb;
 1061         struct thread *td;
 1062         time_t timebase;
 1063         int error;
 1064         
 1065         mtx_assert(&Giant, MA_NOTOWNED);
 1066 
 1067         TSENTER();
 1068 
 1069         td = curthread;
 1070 
 1071         sb = sbuf_new_auto();
 1072         vfs_mountroot_conf0(sb);
 1073         sbuf_finish(sb);
 1074 
 1075         error = vfs_mountroot_devfs(td, &mp);
 1076         while (!error) {
 1077                 error = vfs_mountroot_parse(sb, mp);
 1078                 if (!error) {
 1079                         vfs_mountroot_shuffle(td, mp);
 1080                         sbuf_clear(sb);
 1081                         error = vfs_mountroot_readconf(td, sb);
 1082                         sbuf_finish(sb);
 1083                 }
 1084         }
 1085 
 1086         sbuf_delete(sb);
 1087 
 1088         /*
 1089          * Iterate over all currently mounted file systems and use
 1090          * the time stamp found to check and/or initialize the RTC.
 1091          * Call inittodr() only once and pass it the largest of the
 1092          * timestamps we encounter.
 1093          */
 1094         timebase = 0;
 1095         mtx_lock(&mountlist_mtx);
 1096         mp = TAILQ_FIRST(&mountlist);
 1097         while (mp != NULL) {
 1098                 if (mp->mnt_time > timebase)
 1099                         timebase = mp->mnt_time;
 1100                 mp = TAILQ_NEXT(mp, mnt_list);
 1101         }
 1102         mtx_unlock(&mountlist_mtx);
 1103         inittodr(timebase);
 1104 
 1105         /* Keep prison0's root in sync with the global rootvnode. */
 1106         mtx_lock(&prison0.pr_mtx);
 1107         prison0.pr_root = rootvnode;
 1108         vref(prison0.pr_root);
 1109         mtx_unlock(&prison0.pr_mtx);
 1110 
 1111         mtx_lock(&root_holds_mtx);
 1112         atomic_store_rel_int(&root_mount_complete, 1);
 1113         wakeup(&root_mount_complete);
 1114         mtx_unlock(&root_holds_mtx);
 1115 
 1116         EVENTHANDLER_INVOKE(mountroot);
 1117 
 1118         TSEXIT();
 1119 }
 1120 
 1121 static struct mntarg *
 1122 parse_mountroot_options(struct mntarg *ma, const char *options)
 1123 {
 1124         char *p;
 1125         char *name, *name_arg;
 1126         char *val, *val_arg;
 1127         char *opts;
 1128 
 1129         if (options == NULL || options[0] == '\0')
 1130                 return (ma);
 1131 
 1132         p = opts = strdup(options, M_MOUNT);
 1133         if (opts == NULL) {
 1134                 return (ma);
 1135         }
 1136 
 1137         while((name = strsep(&p, ",")) != NULL) {
 1138                 if (name[0] == '\0')
 1139                         break;
 1140 
 1141                 val = strchr(name, '=');
 1142                 if (val != NULL) {
 1143                         *val = '\0';
 1144                         ++val;
 1145                 }
 1146                 if( strcmp(name, "rw") == 0 ||
 1147                     strcmp(name, "noro") == 0) {
 1148                         /*
 1149                          * The first time we mount the root file system,
 1150                          * we need to mount 'ro', so We need to ignore
 1151                          * 'rw' and 'noro' mount options.
 1152                          */
 1153                         continue;
 1154                 }
 1155                 name_arg = strdup(name, M_MOUNT);
 1156                 val_arg = NULL;
 1157                 if (val != NULL)
 1158                         val_arg = strdup(val, M_MOUNT);
 1159 
 1160                 ma = mount_arg(ma, name_arg, val_arg,
 1161                     (val_arg != NULL ? -1 : 0));
 1162         }
 1163         free(opts, M_MOUNT);
 1164         return (ma);
 1165 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/vfs_mountroot.c

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