The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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

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    1 /*-
    2  * Copyright (c) 2010 Marcel Moolenaar
    3  * Copyright (c) 1999-2004 Poul-Henning Kamp
    4  * Copyright (c) 1999 Michael Smith
    5  * Copyright (c) 1989, 1993
    6  *      The Regents of the University of California.  All rights reserved.
    7  * (c) UNIX System Laboratories, Inc.
    8  * All or some portions of this file are derived from material licensed
    9  * to the University of California by American Telephone and Telegraph
   10  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   11  * the permission of UNIX System Laboratories, Inc.
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  * 4. Neither the name of the University nor the names of its contributors
   22  *    may be used to endorse or promote products derived from this software
   23  *    without specific prior written permission.
   24  *
   25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   35  * SUCH DAMAGE.
   36  */
   37 
   38 #include "opt_rootdevname.h"
   39 
   40 #include <sys/cdefs.h>
   41 __FBSDID("$FreeBSD: releng/11.0/sys/kern/vfs_mountroot.c 299523 2016-05-12 07:38:10Z trasz $");
   42 
   43 #include <sys/param.h>
   44 #include <sys/conf.h>
   45 #include <sys/cons.h>
   46 #include <sys/fcntl.h>
   47 #include <sys/jail.h>
   48 #include <sys/kernel.h>
   49 #include <sys/malloc.h>
   50 #include <sys/mdioctl.h>
   51 #include <sys/mount.h>
   52 #include <sys/mutex.h>
   53 #include <sys/namei.h>
   54 #include <sys/priv.h>
   55 #include <sys/proc.h>
   56 #include <sys/filedesc.h>
   57 #include <sys/reboot.h>
   58 #include <sys/sbuf.h>
   59 #include <sys/stat.h>
   60 #include <sys/syscallsubr.h>
   61 #include <sys/sysproto.h>
   62 #include <sys/sx.h>
   63 #include <sys/sysctl.h>
   64 #include <sys/sysent.h>
   65 #include <sys/systm.h>
   66 #include <sys/vnode.h>
   67 
   68 #include <geom/geom.h>
   69 
   70 /*
   71  * The root filesystem is detailed in the kernel environment variable
   72  * vfs.root.mountfrom, which is expected to be in the general format
   73  *
   74  * <vfsname>:[<path>][  <vfsname>:[<path>] ...]
   75  * vfsname   := the name of a VFS known to the kernel and capable
   76  *              of being mounted as root
   77  * path      := disk device name or other data used by the filesystem
   78  *              to locate its physical store
   79  *
   80  * If the environment variable vfs.root.mountfrom is a space separated list,
   81  * each list element is tried in turn and the root filesystem will be mounted
   82  * from the first one that succeeds.
   83  *
   84  * The environment variable vfs.root.mountfrom.options is a comma delimited
   85  * set of string mount options.  These mount options must be parseable
   86  * by nmount() in the kernel.
   87  */
   88 
   89 static int parse_mount(char **);
   90 static struct mntarg *parse_mountroot_options(struct mntarg *, const char *);
   91 static int sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS);
   92 static void vfs_mountroot_wait(void);
   93 static int vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev);
   94 
   95 /*
   96  * The vnode of the system's root (/ in the filesystem, without chroot
   97  * active.)
   98  */
   99 struct vnode *rootvnode;
  100 
  101 /*
  102  * Mount of the system's /dev.
  103  */
  104 struct mount *rootdevmp;
  105 
  106 char *rootdevnames[2] = {NULL, NULL};
  107 
  108 struct mtx root_holds_mtx;
  109 MTX_SYSINIT(root_holds, &root_holds_mtx, "root_holds", MTX_DEF);
  110 
  111 struct root_hold_token {
  112         const char                      *who;
  113         LIST_ENTRY(root_hold_token)     list;
  114 };
  115 
  116 static LIST_HEAD(, root_hold_token)     root_holds =
  117     LIST_HEAD_INITIALIZER(root_holds);
  118 
  119 enum action {
  120         A_CONTINUE,
  121         A_PANIC,
  122         A_REBOOT,
  123         A_RETRY
  124 };
  125 
  126 static enum action root_mount_onfail = A_CONTINUE;
  127 
  128 static int root_mount_mddev;
  129 static int root_mount_complete;
  130 
  131 /* By default wait up to 3 seconds for devices to appear. */
  132 static int root_mount_timeout = 3;
  133 TUNABLE_INT("vfs.mountroot.timeout", &root_mount_timeout);
  134 
  135 SYSCTL_PROC(_vfs, OID_AUTO, root_mount_hold,
  136     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
  137     NULL, 0, sysctl_vfs_root_mount_hold, "A",
  138     "List of root mount hold tokens");
  139 
  140 static int
  141 sysctl_vfs_root_mount_hold(SYSCTL_HANDLER_ARGS)
  142 {
  143         struct sbuf sb;
  144         struct root_hold_token *h;
  145         int error;
  146 
  147         sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
  148 
  149         mtx_lock(&root_holds_mtx);
  150         LIST_FOREACH(h, &root_holds, list) {
  151                 if (h != LIST_FIRST(&root_holds))
  152                         sbuf_putc(&sb, ' ');
  153                 sbuf_printf(&sb, "%s", h->who);
  154         }
  155         mtx_unlock(&root_holds_mtx);
  156 
  157         error = sbuf_finish(&sb);
  158         if (error == 0)
  159                 error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
  160         sbuf_delete(&sb);
  161         return (error);
  162 }
  163 
  164 struct root_hold_token *
  165 root_mount_hold(const char *identifier)
  166 {
  167         struct root_hold_token *h;
  168 
  169         if (root_mounted())
  170                 return (NULL);
  171 
  172         h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
  173         h->who = identifier;
  174         mtx_lock(&root_holds_mtx);
  175         LIST_INSERT_HEAD(&root_holds, h, list);
  176         mtx_unlock(&root_holds_mtx);
  177         return (h);
  178 }
  179 
  180 void
  181 root_mount_rel(struct root_hold_token *h)
  182 {
  183 
  184         if (h == NULL)
  185                 return;
  186         mtx_lock(&root_holds_mtx);
  187         LIST_REMOVE(h, list);
  188         wakeup(&root_holds);
  189         mtx_unlock(&root_holds_mtx);
  190         free(h, M_DEVBUF);
  191 }
  192 
  193 int
  194 root_mounted(void)
  195 {
  196 
  197         /* No mutex is acquired here because int stores are atomic. */
  198         return (root_mount_complete);
  199 }
  200 
  201 static void
  202 set_rootvnode(void)
  203 {
  204         struct proc *p;
  205 
  206         if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
  207                 panic("Cannot find root vnode");
  208 
  209         VOP_UNLOCK(rootvnode, 0);
  210 
  211         p = curthread->td_proc;
  212         FILEDESC_XLOCK(p->p_fd);
  213 
  214         if (p->p_fd->fd_cdir != NULL)
  215                 vrele(p->p_fd->fd_cdir);
  216         p->p_fd->fd_cdir = rootvnode;
  217         VREF(rootvnode);
  218 
  219         if (p->p_fd->fd_rdir != NULL)
  220                 vrele(p->p_fd->fd_rdir);
  221         p->p_fd->fd_rdir = rootvnode;
  222         VREF(rootvnode);
  223 
  224         FILEDESC_XUNLOCK(p->p_fd);
  225 }
  226 
  227 static int
  228 vfs_mountroot_devfs(struct thread *td, struct mount **mpp)
  229 {
  230         struct vfsoptlist *opts;
  231         struct vfsconf *vfsp;
  232         struct mount *mp;
  233         int error;
  234 
  235         *mpp = NULL;
  236 
  237         if (rootdevmp != NULL) {
  238                 /*
  239                  * Already have /dev; this happens during rerooting.
  240                  */
  241                 error = vfs_busy(rootdevmp, 0);
  242                 if (error != 0)
  243                         return (error);
  244                 *mpp = rootdevmp;
  245         } else {
  246                 vfsp = vfs_byname("devfs");
  247                 KASSERT(vfsp != NULL, ("Could not find devfs by name"));
  248                 if (vfsp == NULL)
  249                         return (ENOENT);
  250 
  251                 mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
  252 
  253                 error = VFS_MOUNT(mp);
  254                 KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
  255                 if (error)
  256                         return (error);
  257 
  258                 opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
  259                 TAILQ_INIT(opts);
  260                 mp->mnt_opt = opts;
  261 
  262                 mtx_lock(&mountlist_mtx);
  263                 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
  264                 mtx_unlock(&mountlist_mtx);
  265 
  266                 *mpp = mp;
  267                 rootdevmp = mp;
  268         }
  269 
  270         set_rootvnode();
  271 
  272         error = kern_symlinkat(td, "/", AT_FDCWD, "dev", UIO_SYSSPACE);
  273         if (error)
  274                 printf("kern_symlink /dev -> / returns %d\n", error);
  275 
  276         return (error);
  277 }
  278 
  279 static void
  280 vfs_mountroot_shuffle(struct thread *td, struct mount *mpdevfs)
  281 {
  282         struct nameidata nd;
  283         struct mount *mporoot, *mpnroot;
  284         struct vnode *vp, *vporoot, *vpdevfs;
  285         char *fspath;
  286         int error;
  287 
  288         mpnroot = TAILQ_NEXT(mpdevfs, mnt_list);
  289 
  290         /* Shuffle the mountlist. */
  291         mtx_lock(&mountlist_mtx);
  292         mporoot = TAILQ_FIRST(&mountlist);
  293         TAILQ_REMOVE(&mountlist, mpdevfs, mnt_list);
  294         if (mporoot != mpdevfs) {
  295                 TAILQ_REMOVE(&mountlist, mpnroot, mnt_list);
  296                 TAILQ_INSERT_HEAD(&mountlist, mpnroot, mnt_list);
  297         }
  298         TAILQ_INSERT_TAIL(&mountlist, mpdevfs, mnt_list);
  299         mtx_unlock(&mountlist_mtx);
  300 
  301         cache_purgevfs(mporoot);
  302         if (mporoot != mpdevfs)
  303                 cache_purgevfs(mpdevfs);
  304 
  305         VFS_ROOT(mporoot, LK_EXCLUSIVE, &vporoot);
  306 
  307         VI_LOCK(vporoot);
  308         vporoot->v_iflag &= ~VI_MOUNT;
  309         VI_UNLOCK(vporoot);
  310         vporoot->v_mountedhere = NULL;
  311         mporoot->mnt_flag &= ~MNT_ROOTFS;
  312         mporoot->mnt_vnodecovered = NULL;
  313         vput(vporoot);
  314 
  315         /* Set up the new rootvnode, and purge the cache */
  316         mpnroot->mnt_vnodecovered = NULL;
  317         set_rootvnode();
  318         cache_purgevfs(rootvnode->v_mount);
  319 
  320         if (mporoot != mpdevfs) {
  321                 /* Remount old root under /.mount or /mnt */
  322                 fspath = "/.mount";
  323                 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  324                     fspath, td);
  325                 error = namei(&nd);
  326                 if (error) {
  327                         NDFREE(&nd, NDF_ONLY_PNBUF);
  328                         fspath = "/mnt";
  329                         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  330                             fspath, td);
  331                         error = namei(&nd);
  332                 }
  333                 if (!error) {
  334                         vp = nd.ni_vp;
  335                         error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
  336                         if (!error)
  337                                 error = vinvalbuf(vp, V_SAVE, 0, 0);
  338                         if (!error) {
  339                                 cache_purge(vp);
  340                                 mporoot->mnt_vnodecovered = vp;
  341                                 vp->v_mountedhere = mporoot;
  342                                 strlcpy(mporoot->mnt_stat.f_mntonname,
  343                                     fspath, MNAMELEN);
  344                                 VOP_UNLOCK(vp, 0);
  345                         } else
  346                                 vput(vp);
  347                 }
  348                 NDFREE(&nd, NDF_ONLY_PNBUF);
  349 
  350                 if (error)
  351                         printf("mountroot: unable to remount previous root "
  352                             "under /.mount or /mnt (error %d)\n", error);
  353         }
  354 
  355         /* Remount devfs under /dev */
  356         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
  357         error = namei(&nd);
  358         if (!error) {
  359                 vp = nd.ni_vp;
  360                 error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
  361                 if (!error)
  362                         error = vinvalbuf(vp, V_SAVE, 0, 0);
  363                 if (!error) {
  364                         vpdevfs = mpdevfs->mnt_vnodecovered;
  365                         if (vpdevfs != NULL) {
  366                                 cache_purge(vpdevfs);
  367                                 vpdevfs->v_mountedhere = NULL;
  368                                 vrele(vpdevfs);
  369                         }
  370                         mpdevfs->mnt_vnodecovered = vp;
  371                         vp->v_mountedhere = mpdevfs;
  372                         VOP_UNLOCK(vp, 0);
  373                 } else
  374                         vput(vp);
  375         }
  376         if (error)
  377                 printf("mountroot: unable to remount devfs under /dev "
  378                     "(error %d)\n", error);
  379         NDFREE(&nd, NDF_ONLY_PNBUF);
  380 
  381         if (mporoot == mpdevfs) {
  382                 vfs_unbusy(mpdevfs);
  383                 /* Unlink the no longer needed /dev/dev -> / symlink */
  384                 error = kern_unlinkat(td, AT_FDCWD, "/dev/dev",
  385                     UIO_SYSSPACE, 0);
  386                 if (error)
  387                         printf("mountroot: unable to unlink /dev/dev "
  388                             "(error %d)\n", error);
  389         }
  390 }
  391 
  392 /*
  393  * Configuration parser.
  394  */
  395 
  396 /* Parser character classes. */
  397 #define CC_WHITESPACE           -1
  398 #define CC_NONWHITESPACE        -2
  399 
  400 /* Parse errors. */
  401 #define PE_EOF                  -1
  402 #define PE_EOL                  -2
  403 
  404 static __inline int
  405 parse_peek(char **conf)
  406 {
  407 
  408         return (**conf);
  409 }
  410 
  411 static __inline void
  412 parse_poke(char **conf, int c)
  413 {
  414 
  415         **conf = c;
  416 }
  417 
  418 static __inline void
  419 parse_advance(char **conf)
  420 {
  421 
  422         (*conf)++;
  423 }
  424 
  425 static int
  426 parse_skipto(char **conf, int mc)
  427 {
  428         int c, match;
  429 
  430         while (1) {
  431                 c = parse_peek(conf);
  432                 if (c == 0)
  433                         return (PE_EOF);
  434                 switch (mc) {
  435                 case CC_WHITESPACE:
  436                         match = (c == ' ' || c == '\t' || c == '\n') ? 1 : 0;
  437                         break;
  438                 case CC_NONWHITESPACE:
  439                         if (c == '\n')
  440                                 return (PE_EOL);
  441                         match = (c != ' ' && c != '\t') ? 1 : 0;
  442                         break;
  443                 default:
  444                         match = (c == mc) ? 1 : 0;
  445                         break;
  446                 }
  447                 if (match)
  448                         break;
  449                 parse_advance(conf);
  450         }
  451         return (0);
  452 }
  453 
  454 static int
  455 parse_token(char **conf, char **tok)
  456 {
  457         char *p;
  458         size_t len;
  459         int error;
  460 
  461         *tok = NULL;
  462         error = parse_skipto(conf, CC_NONWHITESPACE);
  463         if (error)
  464                 return (error);
  465         p = *conf;
  466         error = parse_skipto(conf, CC_WHITESPACE);
  467         len = *conf - p;
  468         *tok = malloc(len + 1, M_TEMP, M_WAITOK | M_ZERO);
  469         bcopy(p, *tok, len);
  470         return (0);
  471 }
  472 
  473 static void
  474 parse_dir_ask_printenv(const char *var)
  475 {
  476         char *val;
  477 
  478         val = kern_getenv(var);
  479         if (val != NULL) {
  480                 printf("  %s=%s\n", var, val);
  481                 freeenv(val);
  482         }
  483 }
  484 
  485 static int
  486 parse_dir_ask(char **conf)
  487 {
  488         char name[80];
  489         char *mnt;
  490         int error;
  491 
  492         vfs_mountroot_wait();
  493 
  494         printf("\nLoader variables:\n");
  495         parse_dir_ask_printenv("vfs.root.mountfrom");
  496         parse_dir_ask_printenv("vfs.root.mountfrom.options");
  497 
  498         printf("\nManual root filesystem specification:\n");
  499         printf("  <fstype>:<device> [options]\n");
  500         printf("      Mount <device> using filesystem <fstype>\n");
  501         printf("      and with the specified (optional) option list.\n");
  502         printf("\n");
  503         printf("    eg. ufs:/dev/da0s1a\n");
  504         printf("        zfs:tank\n");
  505         printf("        cd9660:/dev/cd0 ro\n");
  506         printf("          (which is equivalent to: ");
  507         printf("mount -t cd9660 -o ro /dev/cd0 /)\n");
  508         printf("\n");
  509         printf("  ?               List valid disk boot devices\n");
  510         printf("  .               Yield 1 second (for background tasks)\n");
  511         printf("  <empty line>    Abort manual input\n");
  512 
  513         do {
  514                 error = EINVAL;
  515                 printf("\nmountroot> ");
  516                 cngets(name, sizeof(name), GETS_ECHO);
  517                 if (name[0] == '\0')
  518                         break;
  519                 if (name[0] == '?' && name[1] == '\0') {
  520                         printf("\nList of GEOM managed disk devices:\n  ");
  521                         g_dev_print();
  522                         continue;
  523                 }
  524                 if (name[0] == '.' && name[1] == '\0') {
  525                         pause("rmask", hz);
  526                         continue;
  527                 }
  528                 mnt = name;
  529                 error = parse_mount(&mnt);
  530                 if (error == -1)
  531                         printf("Invalid file system specification.\n");
  532         } while (error != 0);
  533 
  534         return (error);
  535 }
  536 
  537 static int
  538 parse_dir_md(char **conf)
  539 {
  540         struct stat sb;
  541         struct thread *td;
  542         struct md_ioctl *mdio;
  543         char *path, *tok;
  544         int error, fd, len;
  545 
  546         td = curthread;
  547 
  548         error = parse_token(conf, &tok);
  549         if (error)
  550                 return (error);
  551 
  552         len = strlen(tok);
  553         mdio = malloc(sizeof(*mdio) + len + 1, M_TEMP, M_WAITOK | M_ZERO);
  554         path = (void *)(mdio + 1);
  555         bcopy(tok, path, len);
  556         free(tok, M_TEMP);
  557 
  558         /* Get file status. */
  559         error = kern_statat(td, 0, AT_FDCWD, path, UIO_SYSSPACE, &sb, NULL);
  560         if (error)
  561                 goto out;
  562 
  563         /* Open /dev/mdctl so that we can attach/detach. */
  564         error = kern_openat(td, AT_FDCWD, "/dev/" MDCTL_NAME, UIO_SYSSPACE,
  565             O_RDWR, 0);
  566         if (error)
  567                 goto out;
  568 
  569         fd = td->td_retval[0];
  570         mdio->md_version = MDIOVERSION;
  571         mdio->md_type = MD_VNODE;
  572 
  573         if (root_mount_mddev != -1) {
  574                 mdio->md_unit = root_mount_mddev;
  575                 DROP_GIANT();
  576                 error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
  577                 PICKUP_GIANT();
  578                 /* Ignore errors. We don't care. */
  579                 root_mount_mddev = -1;
  580         }
  581 
  582         mdio->md_file = (void *)(mdio + 1);
  583         mdio->md_options = MD_AUTOUNIT | MD_READONLY;
  584         mdio->md_mediasize = sb.st_size;
  585         mdio->md_unit = 0;
  586         DROP_GIANT();
  587         error = kern_ioctl(td, fd, MDIOCATTACH, (void *)mdio);
  588         PICKUP_GIANT();
  589         if (error)
  590                 goto out;
  591 
  592         if (mdio->md_unit > 9) {
  593                 printf("rootmount: too many md units\n");
  594                 mdio->md_file = NULL;
  595                 mdio->md_options = 0;
  596                 mdio->md_mediasize = 0;
  597                 DROP_GIANT();
  598                 error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
  599                 PICKUP_GIANT();
  600                 /* Ignore errors. We don't care. */
  601                 error = ERANGE;
  602                 goto out;
  603         }
  604 
  605         root_mount_mddev = mdio->md_unit;
  606         printf(MD_NAME "%u attached to %s\n", root_mount_mddev, mdio->md_file);
  607 
  608         error = kern_close(td, fd);
  609 
  610  out:
  611         free(mdio, M_TEMP);
  612         return (error);
  613 }
  614 
  615 static int
  616 parse_dir_onfail(char **conf)
  617 {
  618         char *action;
  619         int error;
  620 
  621         error = parse_token(conf, &action);
  622         if (error)
  623                 return (error);
  624 
  625         if (!strcmp(action, "continue"))
  626                 root_mount_onfail = A_CONTINUE;
  627         else if (!strcmp(action, "panic"))
  628                 root_mount_onfail = A_PANIC;
  629         else if (!strcmp(action, "reboot"))
  630                 root_mount_onfail = A_REBOOT;
  631         else if (!strcmp(action, "retry"))
  632                 root_mount_onfail = A_RETRY;
  633         else {
  634                 printf("rootmount: %s: unknown action\n", action);
  635                 error = EINVAL;
  636         }
  637 
  638         free(action, M_TEMP);
  639         return (0);
  640 }
  641 
  642 static int
  643 parse_dir_timeout(char **conf)
  644 {
  645         char *tok, *endtok;
  646         long secs;
  647         int error;
  648 
  649         error = parse_token(conf, &tok);
  650         if (error)
  651                 return (error);
  652 
  653         secs = strtol(tok, &endtok, 0);
  654         error = (secs < 0 || *endtok != '\0') ? EINVAL : 0;
  655         if (!error)
  656                 root_mount_timeout = secs;
  657         free(tok, M_TEMP);
  658         return (error);
  659 }
  660 
  661 static int
  662 parse_directive(char **conf)
  663 {
  664         char *dir;
  665         int error;
  666 
  667         error = parse_token(conf, &dir);
  668         if (error)
  669                 return (error);
  670 
  671         if (strcmp(dir, ".ask") == 0)
  672                 error = parse_dir_ask(conf);
  673         else if (strcmp(dir, ".md") == 0)
  674                 error = parse_dir_md(conf);
  675         else if (strcmp(dir, ".onfail") == 0)
  676                 error = parse_dir_onfail(conf);
  677         else if (strcmp(dir, ".timeout") == 0)
  678                 error = parse_dir_timeout(conf);
  679         else {
  680                 printf("mountroot: invalid directive `%s'\n", dir);
  681                 /* Ignore the rest of the line. */
  682                 (void)parse_skipto(conf, '\n');
  683                 error = EINVAL;
  684         }
  685         free(dir, M_TEMP);
  686         return (error);
  687 }
  688 
  689 static int
  690 parse_mount_dev_present(const char *dev)
  691 {
  692         struct nameidata nd;
  693         int error;
  694 
  695         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, dev, curthread);
  696         error = namei(&nd);
  697         if (!error)
  698                 vput(nd.ni_vp);
  699         NDFREE(&nd, NDF_ONLY_PNBUF);
  700         return (error != 0) ? 0 : 1;
  701 }
  702 
  703 #define ERRMSGL 255
  704 static int
  705 parse_mount(char **conf)
  706 {
  707         char *errmsg;
  708         struct mntarg *ma;
  709         char *dev, *fs, *opts, *tok;
  710         int error;
  711 
  712         error = parse_token(conf, &tok);
  713         if (error)
  714                 return (error);
  715         fs = tok;
  716         error = parse_skipto(&tok, ':');
  717         if (error) {
  718                 free(fs, M_TEMP);
  719                 return (error);
  720         }
  721         parse_poke(&tok, '\0');
  722         parse_advance(&tok);
  723         dev = tok;
  724 
  725         if (root_mount_mddev != -1) {
  726                 /* Handle substitution for the md unit number. */
  727                 tok = strstr(dev, "md#");
  728                 if (tok != NULL)
  729                         tok[2] = '' + root_mount_mddev;
  730         }
  731 
  732         /* Parse options. */
  733         error = parse_token(conf, &tok);
  734         opts = (error == 0) ? tok : NULL;
  735 
  736         printf("Trying to mount root from %s:%s [%s]...\n", fs, dev,
  737             (opts != NULL) ? opts : "");
  738 
  739         errmsg = malloc(ERRMSGL, M_TEMP, M_WAITOK | M_ZERO);
  740 
  741         if (vfs_byname(fs) == NULL) {
  742                 strlcpy(errmsg, "unknown file system", ERRMSGL);
  743                 error = ENOENT;
  744                 goto out;
  745         }
  746 
  747         error = vfs_mountroot_wait_if_neccessary(fs, dev);
  748         if (error != 0)
  749                 goto out;
  750 
  751         ma = NULL;
  752         ma = mount_arg(ma, "fstype", fs, -1);
  753         ma = mount_arg(ma, "fspath", "/", -1);
  754         ma = mount_arg(ma, "from", dev, -1);
  755         ma = mount_arg(ma, "errmsg", errmsg, ERRMSGL);
  756         ma = mount_arg(ma, "ro", NULL, 0);
  757         ma = parse_mountroot_options(ma, opts);
  758         error = kernel_mount(ma, MNT_ROOTFS);
  759 
  760  out:
  761         if (error) {
  762                 printf("Mounting from %s:%s failed with error %d",
  763                     fs, dev, error);
  764                 if (errmsg[0] != '\0')
  765                         printf(": %s", errmsg);
  766                 printf(".\n");
  767         }
  768         free(fs, M_TEMP);
  769         free(errmsg, M_TEMP);
  770         if (opts != NULL)
  771                 free(opts, M_TEMP);
  772         /* kernel_mount can return -1 on error. */
  773         return ((error < 0) ? EDOOFUS : error);
  774 }
  775 #undef ERRMSGL
  776 
  777 static int
  778 vfs_mountroot_parse(struct sbuf *sb, struct mount *mpdevfs)
  779 {
  780         struct mount *mp;
  781         char *conf;
  782         int error;
  783 
  784         root_mount_mddev = -1;
  785 
  786 retry:
  787         conf = sbuf_data(sb);
  788         mp = TAILQ_NEXT(mpdevfs, mnt_list);
  789         error = (mp == NULL) ? 0 : EDOOFUS;
  790         root_mount_onfail = A_CONTINUE;
  791         while (mp == NULL) {
  792                 error = parse_skipto(&conf, CC_NONWHITESPACE);
  793                 if (error == PE_EOL) {
  794                         parse_advance(&conf);
  795                         continue;
  796                 }
  797                 if (error < 0)
  798                         break;
  799                 switch (parse_peek(&conf)) {
  800                 case '#':
  801                         error = parse_skipto(&conf, '\n');
  802                         break;
  803                 case '.':
  804                         error = parse_directive(&conf);
  805                         break;
  806                 default:
  807                         error = parse_mount(&conf);
  808                         if (error == -1) {
  809                                 printf("mountroot: invalid file system "
  810                                     "specification.\n");
  811                                 error = 0;
  812                         }
  813                         break;
  814                 }
  815                 if (error < 0)
  816                         break;
  817                 /* Ignore any trailing garbage on the line. */
  818                 if (parse_peek(&conf) != '\n') {
  819                         printf("mountroot: advancing to next directive...\n");
  820                         (void)parse_skipto(&conf, '\n');
  821                 }
  822                 mp = TAILQ_NEXT(mpdevfs, mnt_list);
  823         }
  824         if (mp != NULL)
  825                 return (0);
  826 
  827         /*
  828          * We failed to mount (a new) root.
  829          */
  830         switch (root_mount_onfail) {
  831         case A_CONTINUE:
  832                 break;
  833         case A_PANIC:
  834                 panic("mountroot: unable to (re-)mount root.");
  835                 /* NOTREACHED */
  836         case A_RETRY:
  837                 goto retry;
  838         case A_REBOOT:
  839                 kern_reboot(RB_NOSYNC);
  840                 /* NOTREACHED */
  841         }
  842 
  843         return (error);
  844 }
  845 
  846 static void
  847 vfs_mountroot_conf0(struct sbuf *sb)
  848 {
  849         char *s, *tok, *mnt, *opt;
  850         int error;
  851 
  852         sbuf_printf(sb, ".onfail panic\n");
  853         sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
  854         if (boothowto & RB_ASKNAME)
  855                 sbuf_printf(sb, ".ask\n");
  856 #ifdef ROOTDEVNAME
  857         if (boothowto & RB_DFLTROOT)
  858                 sbuf_printf(sb, "%s\n", ROOTDEVNAME);
  859 #endif
  860         if (boothowto & RB_CDROM) {
  861                 sbuf_printf(sb, "cd9660:/dev/cd0 ro\n");
  862                 sbuf_printf(sb, ".timeout 0\n");
  863                 sbuf_printf(sb, "cd9660:/dev/cd1 ro\n");
  864                 sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
  865         }
  866         s = kern_getenv("vfs.root.mountfrom");
  867         if (s != NULL) {
  868                 opt = kern_getenv("vfs.root.mountfrom.options");
  869                 tok = s;
  870                 error = parse_token(&tok, &mnt);
  871                 while (!error) {
  872                         sbuf_printf(sb, "%s %s\n", mnt,
  873                             (opt != NULL) ? opt : "");
  874                         free(mnt, M_TEMP);
  875                         error = parse_token(&tok, &mnt);
  876                 }
  877                 if (opt != NULL)
  878                         freeenv(opt);
  879                 freeenv(s);
  880         }
  881         if (rootdevnames[0] != NULL)
  882                 sbuf_printf(sb, "%s\n", rootdevnames[0]);
  883         if (rootdevnames[1] != NULL)
  884                 sbuf_printf(sb, "%s\n", rootdevnames[1]);
  885 #ifdef ROOTDEVNAME
  886         if (!(boothowto & RB_DFLTROOT))
  887                 sbuf_printf(sb, "%s\n", ROOTDEVNAME);
  888 #endif
  889         if (!(boothowto & RB_ASKNAME))
  890                 sbuf_printf(sb, ".ask\n");
  891 }
  892 
  893 static int
  894 vfs_mountroot_readconf(struct thread *td, struct sbuf *sb)
  895 {
  896         static char buf[128];
  897         struct nameidata nd;
  898         off_t ofs;
  899         ssize_t resid;
  900         int error, flags, len;
  901 
  902         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/.mount.conf", td);
  903         flags = FREAD;
  904         error = vn_open(&nd, &flags, 0, NULL);
  905         if (error)
  906                 return (error);
  907 
  908         NDFREE(&nd, NDF_ONLY_PNBUF);
  909         ofs = 0;
  910         len = sizeof(buf) - 1;
  911         while (1) {
  912                 error = vn_rdwr(UIO_READ, nd.ni_vp, buf, len, ofs,
  913                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  914                     NOCRED, &resid, td);
  915                 if (error)
  916                         break;
  917                 if (resid == len)
  918                         break;
  919                 buf[len - resid] = 0;
  920                 sbuf_printf(sb, "%s", buf);
  921                 ofs += len - resid;
  922         }
  923 
  924         VOP_UNLOCK(nd.ni_vp, 0);
  925         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  926         return (error);
  927 }
  928 
  929 static void
  930 vfs_mountroot_wait(void)
  931 {
  932         struct root_hold_token *h;
  933         struct timeval lastfail;
  934         int curfail;
  935 
  936         curfail = 0;
  937         while (1) {
  938                 DROP_GIANT();
  939                 g_waitidle();
  940                 PICKUP_GIANT();
  941                 mtx_lock(&root_holds_mtx);
  942                 if (LIST_EMPTY(&root_holds)) {
  943                         mtx_unlock(&root_holds_mtx);
  944                         break;
  945                 }
  946                 if (ppsratecheck(&lastfail, &curfail, 1)) {
  947                         printf("Root mount waiting for:");
  948                         LIST_FOREACH(h, &root_holds, list)
  949                                 printf(" %s", h->who);
  950                         printf("\n");
  951                 }
  952                 msleep(&root_holds, &root_holds_mtx, PZERO | PDROP, "roothold",
  953                     hz);
  954         }
  955 }
  956 
  957 static int
  958 vfs_mountroot_wait_if_neccessary(const char *fs, const char *dev)
  959 {
  960         int delay, timeout;
  961 
  962         /*
  963          * In case of ZFS and NFS we don't have a way to wait for
  964          * specific device.
  965          */
  966         if (strcmp(fs, "zfs") == 0 || strstr(fs, "nfs") != NULL ||
  967             dev[0] == '\0') {
  968                 vfs_mountroot_wait();
  969                 return (0);
  970         }
  971 
  972         /*
  973          * Otherwise, no point in waiting if the device is already there.
  974          * Note that we must wait for GEOM to finish reconfiguring itself,
  975          * eg for geom_part(4) to finish tasting.
  976          */
  977         DROP_GIANT();
  978         g_waitidle();
  979         PICKUP_GIANT();
  980         if (parse_mount_dev_present(dev))
  981                 return (0);
  982 
  983         /*
  984          * No luck.  Let's wait.  This code looks weird, but it's that way
  985          * to behave exactly as it used to work before.
  986          */
  987         vfs_mountroot_wait();
  988         printf("mountroot: waiting for device %s...\n", dev);
  989         delay = hz / 10;
  990         timeout = root_mount_timeout * hz;
  991         do {
  992                 pause("rmdev", delay);
  993                 timeout -= delay;
  994         } while (timeout > 0 && !parse_mount_dev_present(dev));
  995 
  996         if (timeout <= 0)
  997                 return (ENODEV);
  998 
  999         return (0);
 1000 }
 1001 
 1002 void
 1003 vfs_mountroot(void)
 1004 {
 1005         struct mount *mp;
 1006         struct sbuf *sb;
 1007         struct thread *td;
 1008         time_t timebase;
 1009         int error;
 1010 
 1011         td = curthread;
 1012 
 1013         sb = sbuf_new_auto();
 1014         vfs_mountroot_conf0(sb);
 1015         sbuf_finish(sb);
 1016 
 1017         error = vfs_mountroot_devfs(td, &mp);
 1018         while (!error) {
 1019                 error = vfs_mountroot_parse(sb, mp);
 1020                 if (!error) {
 1021                         vfs_mountroot_shuffle(td, mp);
 1022                         sbuf_clear(sb);
 1023                         error = vfs_mountroot_readconf(td, sb);
 1024                         sbuf_finish(sb);
 1025                 }
 1026         }
 1027 
 1028         sbuf_delete(sb);
 1029 
 1030         /*
 1031          * Iterate over all currently mounted file systems and use
 1032          * the time stamp found to check and/or initialize the RTC.
 1033          * Call inittodr() only once and pass it the largest of the
 1034          * timestamps we encounter.
 1035          */
 1036         timebase = 0;
 1037         mtx_lock(&mountlist_mtx);
 1038         mp = TAILQ_FIRST(&mountlist);
 1039         while (mp != NULL) {
 1040                 if (mp->mnt_time > timebase)
 1041                         timebase = mp->mnt_time;
 1042                 mp = TAILQ_NEXT(mp, mnt_list);
 1043         }
 1044         mtx_unlock(&mountlist_mtx);
 1045         inittodr(timebase);
 1046 
 1047         /* Keep prison0's root in sync with the global rootvnode. */
 1048         mtx_lock(&prison0.pr_mtx);
 1049         prison0.pr_root = rootvnode;
 1050         vref(prison0.pr_root);
 1051         mtx_unlock(&prison0.pr_mtx);
 1052 
 1053         mtx_lock(&root_holds_mtx);
 1054         atomic_store_rel_int(&root_mount_complete, 1);
 1055         wakeup(&root_mount_complete);
 1056         mtx_unlock(&root_holds_mtx);
 1057 
 1058         EVENTHANDLER_INVOKE(mountroot);
 1059 }
 1060 
 1061 static struct mntarg *
 1062 parse_mountroot_options(struct mntarg *ma, const char *options)
 1063 {
 1064         char *p;
 1065         char *name, *name_arg;
 1066         char *val, *val_arg;
 1067         char *opts;
 1068 
 1069         if (options == NULL || options[0] == '\0')
 1070                 return (ma);
 1071 
 1072         p = opts = strdup(options, M_MOUNT);
 1073         if (opts == NULL) {
 1074                 return (ma);
 1075         }
 1076 
 1077         while((name = strsep(&p, ",")) != NULL) {
 1078                 if (name[0] == '\0')
 1079                         break;
 1080 
 1081                 val = strchr(name, '=');
 1082                 if (val != NULL) {
 1083                         *val = '\0';
 1084                         ++val;
 1085                 }
 1086                 if( strcmp(name, "rw") == 0 ||
 1087                     strcmp(name, "noro") == 0) {
 1088                         /*
 1089                          * The first time we mount the root file system,
 1090                          * we need to mount 'ro', so We need to ignore
 1091                          * 'rw' and 'noro' mount options.
 1092                          */
 1093                         continue;
 1094                 }
 1095                 name_arg = strdup(name, M_MOUNT);
 1096                 val_arg = NULL;
 1097                 if (val != NULL)
 1098                         val_arg = strdup(val, M_MOUNT);
 1099 
 1100                 ma = mount_arg(ma, name_arg, val_arg,
 1101                     (val_arg != NULL ? -1 : 0));
 1102         }
 1103         free(opts, M_MOUNT);
 1104         return (ma);
 1105 }

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