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: releng/12.0/sys/kern/vfs_mountroot.c 337837 2018-08-15 12:12:21Z trasz $");
   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 struct root_hold_token {
  114         const char                      *who;
  115         LIST_ENTRY(root_hold_token)     list;
  116 };
  117 
  118 static LIST_HEAD(, root_hold_token)     root_holds =
  119     LIST_HEAD_INITIALIZER(root_holds);
  120 
  121 enum action {
  122         A_CONTINUE,
  123         A_PANIC,
  124         A_REBOOT,
  125         A_RETRY
  126 };
  127 
  128 static enum action root_mount_onfail = A_CONTINUE;
  129 
  130 static int root_mount_mddev;
  131 static int root_mount_complete;
  132 
  133 /* By default wait up to 3 seconds for devices to appear. */
  134 static int root_mount_timeout = 3;
  135 TUNABLE_INT("vfs.mountroot.timeout", &root_mount_timeout);
  136 
  137 static int root_mount_always_wait = 0;
  138 SYSCTL_INT(_vfs, OID_AUTO, root_mount_always_wait, CTLFLAG_RDTUN,
  139     &root_mount_always_wait, 0,
  140     "Wait for root mount holds even if the root device already exists");
  141 
  142 SYSCTL_PROC(_vfs, OID_AUTO, root_mount_hold,
  143     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
  144     NULL, 0, sysctl_vfs_root_mount_hold, "A",
  145     "List of root mount hold tokens");
  146 
  147 static int
  148 sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS)
  149 {
  150         struct sbuf sb;
  151         struct root_hold_token *h;
  152         int error;
  153 
  154         sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
  155 
  156         mtx_lock(&root_holds_mtx);
  157         LIST_FOREACH(h, &root_holds, list) {
  158                 if (h != LIST_FIRST(&root_holds))
  159                         sbuf_putc(&sb, ' ');
  160                 sbuf_printf(&sb, "%s", h->who);
  161         }
  162         mtx_unlock(&root_holds_mtx);
  163 
  164         error = sbuf_finish(&sb);
  165         if (error == 0)
  166                 error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
  167         sbuf_delete(&sb);
  168         return (error);
  169 }
  170 
  171 struct root_hold_token *
  172 root_mount_hold(const char *identifier)
  173 {
  174         struct root_hold_token *h;
  175 
  176         h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
  177         h->who = identifier;
  178         mtx_lock(&root_holds_mtx);
  179         TSHOLD("root mount");
  180         LIST_INSERT_HEAD(&root_holds, h, list);
  181         mtx_unlock(&root_holds_mtx);
  182         return (h);
  183 }
  184 
  185 void
  186 root_mount_rel(struct root_hold_token *h)
  187 {
  188 
  189         if (h == NULL)
  190                 return;
  191 
  192         mtx_lock(&root_holds_mtx);
  193         LIST_REMOVE(h, list);
  194         TSRELEASE("root mount");
  195         wakeup(&root_holds);
  196         mtx_unlock(&root_holds_mtx);
  197         free(h, M_DEVBUF);
  198 }
  199 
  200 int
  201 root_mounted(void)
  202 {
  203 
  204         /* No mutex is acquired here because int stores are atomic. */
  205         return (root_mount_complete);
  206 }
  207 
  208 static void
  209 set_rootvnode(void)
  210 {
  211         struct proc *p;
  212 
  213         if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
  214                 panic("Cannot find root vnode");
  215 
  216         VOP_UNLOCK(rootvnode, 0);
  217 
  218         p = curthread->td_proc;
  219         FILEDESC_XLOCK(p->p_fd);
  220 
  221         if (p->p_fd->fd_cdir != NULL)
  222                 vrele(p->p_fd->fd_cdir);
  223         p->p_fd->fd_cdir = rootvnode;
  224         VREF(rootvnode);
  225 
  226         if (p->p_fd->fd_rdir != NULL)
  227                 vrele(p->p_fd->fd_rdir);
  228         p->p_fd->fd_rdir = rootvnode;
  229         VREF(rootvnode);
  230 
  231         FILEDESC_XUNLOCK(p->p_fd);
  232 }
  233 
  234 static int
  235 vfs_mountroot_devfs(struct thread *td, struct mount **mpp)
  236 {
  237         struct vfsoptlist *opts;
  238         struct vfsconf *vfsp;
  239         struct mount *mp;
  240         int error;
  241 
  242         *mpp = NULL;
  243 
  244         if (rootdevmp != NULL) {
  245                 /*
  246                  * Already have /dev; this happens during rerooting.
  247                  */
  248                 error = vfs_busy(rootdevmp, 0);
  249                 if (error != 0)
  250                         return (error);
  251                 *mpp = rootdevmp;
  252         } else {
  253                 vfsp = vfs_byname("devfs");
  254                 KASSERT(vfsp != NULL, ("Could not find devfs by name"));
  255                 if (vfsp == NULL)
  256                         return (ENOENT);
  257 
  258                 mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
  259 
  260                 error = VFS_MOUNT(mp);
  261                 KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
  262                 if (error)
  263                         return (error);
  264 
  265                 opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
  266                 TAILQ_INIT(opts);
  267                 mp->mnt_opt = opts;
  268 
  269                 mtx_lock(&mountlist_mtx);
  270                 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
  271                 mtx_unlock(&mountlist_mtx);
  272 
  273                 *mpp = mp;
  274                 rootdevmp = mp;
  275         }
  276 
  277         set_rootvnode();
  278 
  279         error = kern_symlinkat(td, "/", AT_FDCWD, "dev", UIO_SYSSPACE);
  280         if (error)
  281                 printf("kern_symlink /dev -> / returns %d\n", error);
  282 
  283         return (error);
  284 }
  285 
  286 static void
  287 vfs_mountroot_shuffle(struct thread *td, struct mount *mpdevfs)
  288 {
  289         struct nameidata nd;
  290         struct mount *mporoot, *mpnroot;
  291         struct vnode *vp, *vporoot, *vpdevfs;
  292         char *fspath;
  293         int error;
  294 
  295         mpnroot = TAILQ_NEXT(mpdevfs, mnt_list);
  296 
  297         /* Shuffle the mountlist. */
  298         mtx_lock(&mountlist_mtx);
  299         mporoot = TAILQ_FIRST(&mountlist);
  300         TAILQ_REMOVE(&mountlist, mpdevfs, mnt_list);
  301         if (mporoot != mpdevfs) {
  302                 TAILQ_REMOVE(&mountlist, mpnroot, mnt_list);
  303                 TAILQ_INSERT_HEAD(&mountlist, mpnroot, mnt_list);
  304         }
  305         TAILQ_INSERT_TAIL(&mountlist, mpdevfs, mnt_list);
  306         mtx_unlock(&mountlist_mtx);
  307 
  308         cache_purgevfs(mporoot, true);
  309         if (mporoot != mpdevfs)
  310                 cache_purgevfs(mpdevfs, true);
  311 
  312         VFS_ROOT(mporoot, LK_EXCLUSIVE, &vporoot);
  313 
  314         VI_LOCK(vporoot);
  315         vporoot->v_iflag &= ~VI_MOUNT;
  316         VI_UNLOCK(vporoot);
  317         vporoot->v_mountedhere = NULL;
  318         mporoot->mnt_flag &= ~MNT_ROOTFS;
  319         mporoot->mnt_vnodecovered = NULL;
  320         vput(vporoot);
  321 
  322         /* Set up the new rootvnode, and purge the cache */
  323         mpnroot->mnt_vnodecovered = NULL;
  324         set_rootvnode();
  325         cache_purgevfs(rootvnode->v_mount, true);
  326 
  327         if (mporoot != mpdevfs) {
  328                 /* Remount old root under /.mount or /mnt */
  329                 fspath = "/.mount";
  330                 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  331                     fspath, td);
  332                 error = namei(&nd);
  333                 if (error) {
  334                         NDFREE(&nd, NDF_ONLY_PNBUF);
  335                         fspath = "/mnt";
  336                         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  337                             fspath, td);
  338                         error = namei(&nd);
  339                 }
  340                 if (!error) {
  341                         vp = nd.ni_vp;
  342                         error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
  343                         if (!error)
  344                                 error = vinvalbuf(vp, V_SAVE, 0, 0);
  345                         if (!error) {
  346                                 cache_purge(vp);
  347                                 mporoot->mnt_vnodecovered = vp;
  348                                 vp->v_mountedhere = mporoot;
  349                                 strlcpy(mporoot->mnt_stat.f_mntonname,
  350                                     fspath, MNAMELEN);
  351                                 VOP_UNLOCK(vp, 0);
  352                         } else
  353                                 vput(vp);
  354                 }
  355                 NDFREE(&nd, NDF_ONLY_PNBUF);
  356 
  357                 if (error)
  358                         printf("mountroot: unable to remount previous root "
  359                             "under /.mount or /mnt (error %d)\n", error);
  360         }
  361 
  362         /* Remount devfs under /dev */
  363         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
  364         error = namei(&nd);
  365         if (!error) {
  366                 vp = nd.ni_vp;
  367                 error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
  368                 if (!error)
  369                         error = vinvalbuf(vp, V_SAVE, 0, 0);
  370                 if (!error) {
  371                         vpdevfs = mpdevfs->mnt_vnodecovered;
  372                         if (vpdevfs != NULL) {
  373                                 cache_purge(vpdevfs);
  374                                 vpdevfs->v_mountedhere = NULL;
  375                                 vrele(vpdevfs);
  376                         }
  377                         mpdevfs->mnt_vnodecovered = vp;
  378                         vp->v_mountedhere = mpdevfs;
  379                         VOP_UNLOCK(vp, 0);
  380                 } else
  381                         vput(vp);
  382         }
  383         if (error)
  384                 printf("mountroot: unable to remount devfs under /dev "
  385                     "(error %d)\n", error);
  386         NDFREE(&nd, NDF_ONLY_PNBUF);
  387 
  388         if (mporoot == mpdevfs) {
  389                 vfs_unbusy(mpdevfs);
  390                 /* Unlink the no longer needed /dev/dev -> / symlink */
  391                 error = kern_unlinkat(td, AT_FDCWD, "/dev/dev",
  392                     UIO_SYSSPACE, 0);
  393                 if (error)
  394                         printf("mountroot: unable to unlink /dev/dev "
  395                             "(error %d)\n", error);
  396         }
  397 }
  398 
  399 /*
  400  * Configuration parser.
  401  */
  402 
  403 /* Parser character classes. */
  404 #define CC_WHITESPACE           -1
  405 #define CC_NONWHITESPACE        -2
  406 
  407 /* Parse errors. */
  408 #define PE_EOF                  -1
  409 #define PE_EOL                  -2
  410 
  411 static __inline int
  412 parse_peek(char **conf)
  413 {
  414 
  415         return (**conf);
  416 }
  417 
  418 static __inline void
  419 parse_poke(char **conf, int c)
  420 {
  421 
  422         **conf = c;
  423 }
  424 
  425 static __inline void
  426 parse_advance(char **conf)
  427 {
  428 
  429         (*conf)++;
  430 }
  431 
  432 static int
  433 parse_skipto(char **conf, int mc)
  434 {
  435         int c, match;
  436 
  437         while (1) {
  438                 c = parse_peek(conf);
  439                 if (c == 0)
  440                         return (PE_EOF);
  441                 switch (mc) {
  442                 case CC_WHITESPACE:
  443                         match = (c == ' ' || c == '\t' || c == '\n') ? 1 : 0;
  444                         break;
  445                 case CC_NONWHITESPACE:
  446                         if (c == '\n')
  447                                 return (PE_EOL);
  448                         match = (c != ' ' && c != '\t') ? 1 : 0;
  449                         break;
  450                 default:
  451                         match = (c == mc) ? 1 : 0;
  452                         break;
  453                 }
  454                 if (match)
  455                         break;
  456                 parse_advance(conf);
  457         }
  458         return (0);
  459 }
  460 
  461 static int
  462 parse_token(char **conf, char **tok)
  463 {
  464         char *p;
  465         size_t len;
  466         int error;
  467 
  468         *tok = NULL;
  469         error = parse_skipto(conf, CC_NONWHITESPACE);
  470         if (error)
  471                 return (error);
  472         p = *conf;
  473         error = parse_skipto(conf, CC_WHITESPACE);
  474         len = *conf - p;
  475         *tok = malloc(len + 1, M_TEMP, M_WAITOK | M_ZERO);
  476         bcopy(p, *tok, len);
  477         return (0);
  478 }
  479 
  480 static void
  481 parse_dir_ask_printenv(const char *var)
  482 {
  483         char *val;
  484 
  485         val = kern_getenv(var);
  486         if (val != NULL) {
  487                 printf("  %s=%s\n", var, val);
  488                 freeenv(val);
  489         }
  490 }
  491 
  492 static int
  493 parse_dir_ask(char **conf)
  494 {
  495         char name[80];
  496         char *mnt;
  497         int error;
  498 
  499         vfs_mountroot_wait();
  500 
  501         printf("\nLoader variables:\n");
  502         parse_dir_ask_printenv("vfs.root.mountfrom");
  503         parse_dir_ask_printenv("vfs.root.mountfrom.options");
  504 
  505         printf("\nManual root filesystem specification:\n");
  506         printf("  <fstype>:<device> [options]\n");
  507         printf("      Mount <device> using filesystem <fstype>\n");
  508         printf("      and with the specified (optional) option list.\n");
  509         printf("\n");
  510         printf("    eg. ufs:/dev/da0s1a\n");
  511         printf("        zfs:zroot/ROOT/default\n");
  512         printf("        cd9660:/dev/cd0 ro\n");
  513         printf("          (which is equivalent to: ");
  514         printf("mount -t cd9660 -o ro /dev/cd0 /)\n");
  515         printf("\n");
  516         printf("  ?               List valid disk boot devices\n");
  517         printf("  .               Yield 1 second (for background tasks)\n");
  518         printf("  <empty line>    Abort manual input\n");
  519 
  520         do {
  521                 error = EINVAL;
  522                 printf("\nmountroot> ");
  523                 cngets(name, sizeof(name), GETS_ECHO);
  524                 if (name[0] == '\0')
  525                         break;
  526                 if (name[0] == '?' && name[1] == '\0') {
  527                         printf("\nList of GEOM managed disk devices:\n  ");
  528                         g_dev_print();
  529                         continue;
  530                 }
  531                 if (name[0] == '.' && name[1] == '\0') {
  532                         pause("rmask", hz);
  533                         continue;
  534                 }
  535                 mnt = name;
  536                 error = parse_mount(&mnt);
  537                 if (error == -1)
  538                         printf("Invalid file system specification.\n");
  539         } while (error != 0);
  540 
  541         return (error);
  542 }
  543 
  544 static int
  545 parse_dir_md(char **conf)
  546 {
  547         struct stat sb;
  548         struct thread *td;
  549         struct md_ioctl *mdio;
  550         char *path, *tok;
  551         int error, fd, len;
  552 
  553         td = curthread;
  554 
  555         error = parse_token(conf, &tok);
  556         if (error)
  557                 return (error);
  558 
  559         len = strlen(tok);
  560         mdio = malloc(sizeof(*mdio) + len + 1, M_TEMP, M_WAITOK | M_ZERO);
  561         path = (void *)(mdio + 1);
  562         bcopy(tok, path, len);
  563         free(tok, M_TEMP);
  564 
  565         /* Get file status. */
  566         error = kern_statat(td, 0, AT_FDCWD, path, UIO_SYSSPACE, &sb, NULL);
  567         if (error)
  568                 goto out;
  569 
  570         /* Open /dev/mdctl so that we can attach/detach. */
  571         error = kern_openat(td, AT_FDCWD, "/dev/" MDCTL_NAME, UIO_SYSSPACE,
  572             O_RDWR, 0);
  573         if (error)
  574                 goto out;
  575 
  576         fd = td->td_retval[0];
  577         mdio->md_version = MDIOVERSION;
  578         mdio->md_type = MD_VNODE;
  579 
  580         if (root_mount_mddev != -1) {
  581                 mdio->md_unit = root_mount_mddev;
  582                 error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
  583                 /* Ignore errors. We don't care. */
  584                 root_mount_mddev = -1;
  585         }
  586 
  587         mdio->md_file = (void *)(mdio + 1);
  588         mdio->md_options = MD_AUTOUNIT | MD_READONLY;
  589         mdio->md_mediasize = sb.st_size;
  590         mdio->md_unit = 0;
  591         error = kern_ioctl(td, fd, MDIOCATTACH, (void *)mdio);
  592         if (error)
  593                 goto out;
  594 
  595         if (mdio->md_unit > 9) {
  596                 printf("rootmount: too many md units\n");
  597                 mdio->md_file = NULL;
  598                 mdio->md_options = 0;
  599                 mdio->md_mediasize = 0;
  600                 error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
  601                 /* Ignore errors. We don't care. */
  602                 error = ERANGE;
  603                 goto out;
  604         }
  605 
  606         root_mount_mddev = mdio->md_unit;
  607         printf(MD_NAME "%u attached to %s\n", root_mount_mddev, mdio->md_file);
  608 
  609         error = kern_close(td, fd);
  610 
  611  out:
  612         free(mdio, M_TEMP);
  613         return (error);
  614 }
  615 
  616 static int
  617 parse_dir_onfail(char **conf)
  618 {
  619         char *action;
  620         int error;
  621 
  622         error = parse_token(conf, &action);
  623         if (error)
  624                 return (error);
  625 
  626         if (!strcmp(action, "continue"))
  627                 root_mount_onfail = A_CONTINUE;
  628         else if (!strcmp(action, "panic"))
  629                 root_mount_onfail = A_PANIC;
  630         else if (!strcmp(action, "reboot"))
  631                 root_mount_onfail = A_REBOOT;
  632         else if (!strcmp(action, "retry"))
  633                 root_mount_onfail = A_RETRY;
  634         else {
  635                 printf("rootmount: %s: unknown action\n", action);
  636                 error = EINVAL;
  637         }
  638 
  639         free(action, M_TEMP);
  640         return (0);
  641 }
  642 
  643 static int
  644 parse_dir_timeout(char **conf)
  645 {
  646         char *tok, *endtok;
  647         long secs;
  648         int error;
  649 
  650         error = parse_token(conf, &tok);
  651         if (error)
  652                 return (error);
  653 
  654         secs = strtol(tok, &endtok, 0);
  655         error = (secs < 0 || *endtok != '\0') ? EINVAL : 0;
  656         if (!error)
  657                 root_mount_timeout = secs;
  658         free(tok, M_TEMP);
  659         return (error);
  660 }
  661 
  662 static int
  663 parse_directive(char **conf)
  664 {
  665         char *dir;
  666         int error;
  667 
  668         error = parse_token(conf, &dir);
  669         if (error)
  670                 return (error);
  671 
  672         if (strcmp(dir, ".ask") == 0)
  673                 error = parse_dir_ask(conf);
  674         else if (strcmp(dir, ".md") == 0)
  675                 error = parse_dir_md(conf);
  676         else if (strcmp(dir, ".onfail") == 0)
  677                 error = parse_dir_onfail(conf);
  678         else if (strcmp(dir, ".timeout") == 0)
  679                 error = parse_dir_timeout(conf);
  680         else {
  681                 printf("mountroot: invalid directive `%s'\n", dir);
  682                 /* Ignore the rest of the line. */
  683                 (void)parse_skipto(conf, '\n');
  684                 error = EINVAL;
  685         }
  686         free(dir, M_TEMP);
  687         return (error);
  688 }
  689 
  690 static int
  691 parse_mount_dev_present(const char *dev)
  692 {
  693         struct nameidata nd;
  694         int error;
  695 
  696         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, dev, curthread);
  697         error = namei(&nd);
  698         if (!error)
  699                 vput(nd.ni_vp);
  700         NDFREE(&nd, NDF_ONLY_PNBUF);
  701         return (error != 0) ? 0 : 1;
  702 }
  703 
  704 #define ERRMSGL 255
  705 static int
  706 parse_mount(char **conf)
  707 {
  708         char *errmsg;
  709         struct mntarg *ma;
  710         char *dev, *fs, *opts, *tok;
  711         int delay, error, timeout;
  712 
  713         error = parse_token(conf, &tok);
  714         if (error)
  715                 return (error);
  716         fs = tok;
  717         error = parse_skipto(&tok, ':');
  718         if (error) {
  719                 free(fs, M_TEMP);
  720                 return (error);
  721         }
  722         parse_poke(&tok, '\0');
  723         parse_advance(&tok);
  724         dev = tok;
  725 
  726         if (root_mount_mddev != -1) {
  727                 /* Handle substitution for the md unit number. */
  728                 tok = strstr(dev, "md#");
  729                 if (tok != NULL)
  730                         tok[2] = '' + root_mount_mddev;
  731         }
  732 
  733         /* Parse options. */
  734         error = parse_token(conf, &tok);
  735         opts = (error == 0) ? tok : NULL;
  736 
  737         printf("Trying to mount root from %s:%s [%s]...\n", fs, dev,
  738             (opts != NULL) ? opts : "");
  739 
  740         errmsg = malloc(ERRMSGL, M_TEMP, M_WAITOK | M_ZERO);
  741 
  742         if (vfs_byname(fs) == NULL) {
  743                 strlcpy(errmsg, "unknown file system", ERRMSGL);
  744                 error = ENOENT;
  745                 goto out;
  746         }
  747 
  748         error = vfs_mountroot_wait_if_neccessary(fs, dev);
  749         if (error != 0)
  750                 goto out;
  751 
  752         delay = hz / 10;
  753         timeout = root_mount_timeout * hz;
  754 
  755         for (;;) {
  756                 ma = NULL;
  757                 ma = mount_arg(ma, "fstype", fs, -1);
  758                 ma = mount_arg(ma, "fspath", "/", -1);
  759                 ma = mount_arg(ma, "from", dev, -1);
  760                 ma = mount_arg(ma, "errmsg", errmsg, ERRMSGL);
  761                 ma = mount_arg(ma, "ro", NULL, 0);
  762                 ma = parse_mountroot_options(ma, opts);
  763 
  764                 error = kernel_mount(ma, MNT_ROOTFS);
  765                 if (error == 0 || timeout <= 0)
  766                         break;
  767 
  768                 if (root_mount_timeout * hz == timeout ||
  769                     (bootverbose && timeout % hz == 0)) {
  770                         printf("Mounting from %s:%s failed with error %d; "
  771                             "retrying for %d more second%s\n", fs, dev, error,
  772                             timeout / hz, (timeout / hz > 1) ? "s" : "");
  773                 }
  774                 pause("rmretry", delay);
  775                 timeout -= delay;
  776         }
  777  out:
  778         if (error) {
  779                 printf("Mounting from %s:%s failed with error %d",
  780                     fs, dev, error);
  781                 if (errmsg[0] != '\0')
  782                         printf(": %s", errmsg);
  783                 printf(".\n");
  784         }
  785         free(fs, M_TEMP);
  786         free(errmsg, M_TEMP);
  787         if (opts != NULL)
  788                 free(opts, M_TEMP);
  789         /* kernel_mount can return -1 on error. */
  790         return ((error < 0) ? EDOOFUS : error);
  791 }
  792 #undef ERRMSGL
  793 
  794 static int
  795 vfs_mountroot_parse(struct sbuf *sb, struct mount *mpdevfs)
  796 {
  797         struct mount *mp;
  798         char *conf;
  799         int error;
  800 
  801         root_mount_mddev = -1;
  802 
  803 retry:
  804         conf = sbuf_data(sb);
  805         mp = TAILQ_NEXT(mpdevfs, mnt_list);
  806         error = (mp == NULL) ? 0 : EDOOFUS;
  807         root_mount_onfail = A_CONTINUE;
  808         while (mp == NULL) {
  809                 error = parse_skipto(&conf, CC_NONWHITESPACE);
  810                 if (error == PE_EOL) {
  811                         parse_advance(&conf);
  812                         continue;
  813                 }
  814                 if (error < 0)
  815                         break;
  816                 switch (parse_peek(&conf)) {
  817                 case '#':
  818                         error = parse_skipto(&conf, '\n');
  819                         break;
  820                 case '.':
  821                         error = parse_directive(&conf);
  822                         break;
  823                 default:
  824                         error = parse_mount(&conf);
  825                         if (error == -1) {
  826                                 printf("mountroot: invalid file system "
  827                                     "specification.\n");
  828                                 error = 0;
  829                         }
  830                         break;
  831                 }
  832                 if (error < 0)
  833                         break;
  834                 /* Ignore any trailing garbage on the line. */
  835                 if (parse_peek(&conf) != '\n') {
  836                         printf("mountroot: advancing to next directive...\n");
  837                         (void)parse_skipto(&conf, '\n');
  838                 }
  839                 mp = TAILQ_NEXT(mpdevfs, mnt_list);
  840         }
  841         if (mp != NULL)
  842                 return (0);
  843 
  844         /*
  845          * We failed to mount (a new) root.
  846          */
  847         switch (root_mount_onfail) {
  848         case A_CONTINUE:
  849                 break;
  850         case A_PANIC:
  851                 panic("mountroot: unable to (re-)mount root.");
  852                 /* NOTREACHED */
  853         case A_RETRY:
  854                 goto retry;
  855         case A_REBOOT:
  856                 kern_reboot(RB_NOSYNC);
  857                 /* NOTREACHED */
  858         }
  859 
  860         return (error);
  861 }
  862 
  863 static void
  864 vfs_mountroot_conf0(struct sbuf *sb)
  865 {
  866         char *s, *tok, *mnt, *opt;
  867         int error;
  868 
  869         sbuf_printf(sb, ".onfail panic\n");
  870         sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
  871         if (boothowto & RB_ASKNAME)
  872                 sbuf_printf(sb, ".ask\n");
  873 #ifdef ROOTDEVNAME
  874         if (boothowto & RB_DFLTROOT)
  875                 sbuf_printf(sb, "%s\n", ROOTDEVNAME);
  876 #endif
  877         if (boothowto & RB_CDROM) {
  878                 sbuf_printf(sb, "cd9660:/dev/cd0 ro\n");
  879                 sbuf_printf(sb, ".timeout 0\n");
  880                 sbuf_printf(sb, "cd9660:/dev/cd1 ro\n");
  881                 sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
  882         }
  883         s = kern_getenv("vfs.root.mountfrom");
  884         if (s != NULL) {
  885                 opt = kern_getenv("vfs.root.mountfrom.options");
  886                 tok = s;
  887                 error = parse_token(&tok, &mnt);
  888                 while (!error) {
  889                         sbuf_printf(sb, "%s %s\n", mnt,
  890                             (opt != NULL) ? opt : "");
  891                         free(mnt, M_TEMP);
  892                         error = parse_token(&tok, &mnt);
  893                 }
  894                 if (opt != NULL)
  895                         freeenv(opt);
  896                 freeenv(s);
  897         }
  898         if (rootdevnames[0] != NULL)
  899                 sbuf_printf(sb, "%s\n", rootdevnames[0]);
  900         if (rootdevnames[1] != NULL)
  901                 sbuf_printf(sb, "%s\n", rootdevnames[1]);
  902 #ifdef ROOTDEVNAME
  903         if (!(boothowto & RB_DFLTROOT))
  904                 sbuf_printf(sb, "%s\n", ROOTDEVNAME);
  905 #endif
  906         if (!(boothowto & RB_ASKNAME))
  907                 sbuf_printf(sb, ".ask\n");
  908 }
  909 
  910 static int
  911 vfs_mountroot_readconf(struct thread *td, struct sbuf *sb)
  912 {
  913         static char buf[128];
  914         struct nameidata nd;
  915         off_t ofs;
  916         ssize_t resid;
  917         int error, flags, len;
  918 
  919         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/.mount.conf", td);
  920         flags = FREAD;
  921         error = vn_open(&nd, &flags, 0, NULL);
  922         if (error)
  923                 return (error);
  924 
  925         NDFREE(&nd, NDF_ONLY_PNBUF);
  926         ofs = 0;
  927         len = sizeof(buf) - 1;
  928         while (1) {
  929                 error = vn_rdwr(UIO_READ, nd.ni_vp, buf, len, ofs,
  930                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  931                     NOCRED, &resid, td);
  932                 if (error)
  933                         break;
  934                 if (resid == len)
  935                         break;
  936                 buf[len - resid] = 0;
  937                 sbuf_printf(sb, "%s", buf);
  938                 ofs += len - resid;
  939         }
  940 
  941         VOP_UNLOCK(nd.ni_vp, 0);
  942         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  943         return (error);
  944 }
  945 
  946 static void
  947 vfs_mountroot_wait(void)
  948 {
  949         struct root_hold_token *h;
  950         struct timeval lastfail;
  951         int curfail;
  952 
  953         TSENTER();
  954 
  955         curfail = 0;
  956         while (1) {
  957                 g_waitidle();
  958                 mtx_lock(&root_holds_mtx);
  959                 if (LIST_EMPTY(&root_holds)) {
  960                         mtx_unlock(&root_holds_mtx);
  961                         break;
  962                 }
  963                 if (ppsratecheck(&lastfail, &curfail, 1)) {
  964                         printf("Root mount waiting for:");
  965                         LIST_FOREACH(h, &root_holds, list)
  966                                 printf(" %s", h->who);
  967                         printf("\n");
  968                 }
  969                 TSWAIT("root mount");
  970                 msleep(&root_holds, &root_holds_mtx, PZERO | PDROP, "roothold",
  971                     hz);
  972                 TSUNWAIT("root mount");
  973         }
  974 
  975         TSEXIT();
  976 }
  977 
  978 static int
  979 vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev)
  980 {
  981         int delay, timeout;
  982 
  983         /*
  984          * In case of ZFS and NFS we don't have a way to wait for
  985          * specific device.  Also do the wait if the user forced that
  986          * behaviour by setting vfs.root_mount_always_wait=1.
  987          */
  988         if (strcmp(fs, "zfs") == 0 || strstr(fs, "nfs") != NULL ||
  989             dev[0] == '\0' || root_mount_always_wait != 0) {
  990                 vfs_mountroot_wait();
  991                 return (0);
  992         }
  993 
  994         /*
  995          * Otherwise, no point in waiting if the device is already there.
  996          * Note that we must wait for GEOM to finish reconfiguring itself,
  997          * eg for geom_part(4) to finish tasting.
  998          */
  999         g_waitidle();
 1000         if (parse_mount_dev_present(dev))
 1001                 return (0);
 1002 
 1003         /*
 1004          * No luck.  Let's wait.  This code looks weird, but it's that way
 1005          * to behave exactly as it used to work before.
 1006          */
 1007         vfs_mountroot_wait();
 1008         printf("mountroot: waiting for device %s...\n", dev);
 1009         delay = hz / 10;
 1010         timeout = root_mount_timeout * hz;
 1011         do {
 1012                 pause("rmdev", delay);
 1013                 timeout -= delay;
 1014         } while (timeout > 0 && !parse_mount_dev_present(dev));
 1015 
 1016         if (timeout <= 0)
 1017                 return (ENODEV);
 1018 
 1019         return (0);
 1020 }
 1021 
 1022 void
 1023 vfs_mountroot(void)
 1024 {
 1025         struct mount *mp;
 1026         struct sbuf *sb;
 1027         struct thread *td;
 1028         time_t timebase;
 1029         int error;
 1030         
 1031         mtx_assert(&Giant, MA_NOTOWNED);
 1032 
 1033         TSENTER();
 1034 
 1035         td = curthread;
 1036 
 1037         sb = sbuf_new_auto();
 1038         vfs_mountroot_conf0(sb);
 1039         sbuf_finish(sb);
 1040 
 1041         error = vfs_mountroot_devfs(td, &mp);
 1042         while (!error) {
 1043                 error = vfs_mountroot_parse(sb, mp);
 1044                 if (!error) {
 1045                         vfs_mountroot_shuffle(td, mp);
 1046                         sbuf_clear(sb);
 1047                         error = vfs_mountroot_readconf(td, sb);
 1048                         sbuf_finish(sb);
 1049                 }
 1050         }
 1051 
 1052         sbuf_delete(sb);
 1053 
 1054         /*
 1055          * Iterate over all currently mounted file systems and use
 1056          * the time stamp found to check and/or initialize the RTC.
 1057          * Call inittodr() only once and pass it the largest of the
 1058          * timestamps we encounter.
 1059          */
 1060         timebase = 0;
 1061         mtx_lock(&mountlist_mtx);
 1062         mp = TAILQ_FIRST(&mountlist);
 1063         while (mp != NULL) {
 1064                 if (mp->mnt_time > timebase)
 1065                         timebase = mp->mnt_time;
 1066                 mp = TAILQ_NEXT(mp, mnt_list);
 1067         }
 1068         mtx_unlock(&mountlist_mtx);
 1069         inittodr(timebase);
 1070 
 1071         /* Keep prison0's root in sync with the global rootvnode. */
 1072         mtx_lock(&prison0.pr_mtx);
 1073         prison0.pr_root = rootvnode;
 1074         vref(prison0.pr_root);
 1075         mtx_unlock(&prison0.pr_mtx);
 1076 
 1077         mtx_lock(&root_holds_mtx);
 1078         atomic_store_rel_int(&root_mount_complete, 1);
 1079         wakeup(&root_mount_complete);
 1080         mtx_unlock(&root_holds_mtx);
 1081 
 1082         EVENTHANDLER_INVOKE(mountroot);
 1083 
 1084         TSEXIT();
 1085 }
 1086 
 1087 static struct mntarg *
 1088 parse_mountroot_options(struct mntarg *ma, const char *options)
 1089 {
 1090         char *p;
 1091         char *name, *name_arg;
 1092         char *val, *val_arg;
 1093         char *opts;
 1094 
 1095         if (options == NULL || options[0] == '\0')
 1096                 return (ma);
 1097 
 1098         p = opts = strdup(options, M_MOUNT);
 1099         if (opts == NULL) {
 1100                 return (ma);
 1101         }
 1102 
 1103         while((name = strsep(&p, ",")) != NULL) {
 1104                 if (name[0] == '\0')
 1105                         break;
 1106 
 1107                 val = strchr(name, '=');
 1108                 if (val != NULL) {
 1109                         *val = '\0';
 1110                         ++val;
 1111                 }
 1112                 if( strcmp(name, "rw") == 0 ||
 1113                     strcmp(name, "noro") == 0) {
 1114                         /*
 1115                          * The first time we mount the root file system,
 1116                          * we need to mount 'ro', so We need to ignore
 1117                          * 'rw' and 'noro' mount options.
 1118                          */
 1119                         continue;
 1120                 }
 1121                 name_arg = strdup(name, M_MOUNT);
 1122                 val_arg = NULL;
 1123                 if (val != NULL)
 1124                         val_arg = strdup(val, M_MOUNT);
 1125 
 1126                 ma = mount_arg(ma, name_arg, val_arg,
 1127                     (val_arg != NULL ? -1 : 0));
 1128         }
 1129         free(opts, M_MOUNT);
 1130         return (ma);
 1131 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/vfs_mountroot.c

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