The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_mount.c

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    1 /*-
    2  * Copyright (c) 1999-2004 Poul-Henning Kamp
    3  * Copyright (c) 1999 Michael Smith
    4  * Copyright (c) 1989, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  * (c) UNIX System Laboratories, Inc.
    7  * All or some portions of this file are derived from material licensed
    8  * to the University of California by American Telephone and Telegraph
    9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   10  * the permission of UNIX System Laboratories, Inc.
   11  *
   12  * Redistribution and use in source and binary forms, with or without
   13  * modification, are permitted provided that the following conditions
   14  * are met:
   15  * 1. Redistributions of source code must retain the above copyright
   16  *    notice, this list of conditions and the following disclaimer.
   17  * 2. Redistributions in binary form must reproduce the above copyright
   18  *    notice, this list of conditions and the following disclaimer in the
   19  *    documentation and/or other materials provided with the distribution.
   20  * 4. Neither the name of the University nor the names of its contributors
   21  *    may be used to endorse or promote products derived from this software
   22  *    without specific prior written permission.
   23  *
   24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   34  * SUCH DAMAGE.
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: releng/10.4/sys/kern/vfs_mount.c 309208 2016-11-27 09:14:52Z kib $");
   39 
   40 #include <sys/param.h>
   41 #include <sys/conf.h>
   42 #include <sys/fcntl.h>
   43 #include <sys/jail.h>
   44 #include <sys/kernel.h>
   45 #include <sys/libkern.h>
   46 #include <sys/malloc.h>
   47 #include <sys/mount.h>
   48 #include <sys/mutex.h>
   49 #include <sys/namei.h>
   50 #include <sys/priv.h>
   51 #include <sys/proc.h>
   52 #include <sys/filedesc.h>
   53 #include <sys/reboot.h>
   54 #include <sys/sbuf.h>
   55 #include <sys/syscallsubr.h>
   56 #include <sys/sysproto.h>
   57 #include <sys/sx.h>
   58 #include <sys/sysctl.h>
   59 #include <sys/sysent.h>
   60 #include <sys/systm.h>
   61 #include <sys/vnode.h>
   62 #include <vm/uma.h>
   63 
   64 #include <geom/geom.h>
   65 
   66 #include <machine/stdarg.h>
   67 
   68 #include <security/audit/audit.h>
   69 #include <security/mac/mac_framework.h>
   70 
   71 #define VFS_MOUNTARG_SIZE_MAX   (1024 * 64)
   72 
   73 static int      vfs_domount(struct thread *td, const char *fstype, char *fspath,
   74                     uint64_t fsflags, struct vfsoptlist **optlist);
   75 static void     free_mntarg(struct mntarg *ma);
   76 
   77 static int      usermount = 0;
   78 SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0,
   79     "Unprivileged users may mount and unmount file systems");
   80 
   81 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
   82 static uma_zone_t mount_zone;
   83 
   84 /* List of mounted filesystems. */
   85 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist);
   86 
   87 /* For any iteration/modification of mountlist */
   88 struct mtx mountlist_mtx;
   89 MTX_SYSINIT(mountlist, &mountlist_mtx, "mountlist", MTX_DEF);
   90 
   91 /*
   92  * Global opts, taken by all filesystems
   93  */
   94 static const char *global_opts[] = {
   95         "errmsg",
   96         "fstype",
   97         "fspath",
   98         "ro",
   99         "rw",
  100         "nosuid",
  101         "noexec",
  102         NULL
  103 };
  104 
  105 static int
  106 mount_init(void *mem, int size, int flags)
  107 {
  108         struct mount *mp;
  109 
  110         mp = (struct mount *)mem;
  111         mtx_init(&mp->mnt_mtx, "struct mount mtx", NULL, MTX_DEF);
  112         lockinit(&mp->mnt_explock, PVFS, "explock", 0, 0);
  113         return (0);
  114 }
  115 
  116 static void
  117 mount_fini(void *mem, int size)
  118 {
  119         struct mount *mp;
  120 
  121         mp = (struct mount *)mem;
  122         lockdestroy(&mp->mnt_explock);
  123         mtx_destroy(&mp->mnt_mtx);
  124 }
  125 
  126 static void
  127 vfs_mount_init(void *dummy __unused)
  128 {
  129 
  130         mount_zone = uma_zcreate("Mountpoints", sizeof(struct mount), NULL,
  131             NULL, mount_init, mount_fini, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  132 }
  133 SYSINIT(vfs_mount, SI_SUB_VFS, SI_ORDER_ANY, vfs_mount_init, NULL);
  134 
  135 /*
  136  * ---------------------------------------------------------------------
  137  * Functions for building and sanitizing the mount options
  138  */
  139 
  140 /* Remove one mount option. */
  141 static void
  142 vfs_freeopt(struct vfsoptlist *opts, struct vfsopt *opt)
  143 {
  144 
  145         TAILQ_REMOVE(opts, opt, link);
  146         free(opt->name, M_MOUNT);
  147         if (opt->value != NULL)
  148                 free(opt->value, M_MOUNT);
  149         free(opt, M_MOUNT);
  150 }
  151 
  152 /* Release all resources related to the mount options. */
  153 void
  154 vfs_freeopts(struct vfsoptlist *opts)
  155 {
  156         struct vfsopt *opt;
  157 
  158         while (!TAILQ_EMPTY(opts)) {
  159                 opt = TAILQ_FIRST(opts);
  160                 vfs_freeopt(opts, opt);
  161         }
  162         free(opts, M_MOUNT);
  163 }
  164 
  165 void
  166 vfs_deleteopt(struct vfsoptlist *opts, const char *name)
  167 {
  168         struct vfsopt *opt, *temp;
  169 
  170         if (opts == NULL)
  171                 return;
  172         TAILQ_FOREACH_SAFE(opt, opts, link, temp)  {
  173                 if (strcmp(opt->name, name) == 0)
  174                         vfs_freeopt(opts, opt);
  175         }
  176 }
  177 
  178 static int
  179 vfs_isopt_ro(const char *opt)
  180 {
  181 
  182         if (strcmp(opt, "ro") == 0 || strcmp(opt, "rdonly") == 0 ||
  183             strcmp(opt, "norw") == 0)
  184                 return (1);
  185         return (0);
  186 }
  187 
  188 static int
  189 vfs_isopt_rw(const char *opt)
  190 {
  191 
  192         if (strcmp(opt, "rw") == 0 || strcmp(opt, "noro") == 0)
  193                 return (1);
  194         return (0);
  195 }
  196 
  197 /*
  198  * Check if options are equal (with or without the "no" prefix).
  199  */
  200 static int
  201 vfs_equalopts(const char *opt1, const char *opt2)
  202 {
  203         char *p;
  204 
  205         /* "opt" vs. "opt" or "noopt" vs. "noopt" */
  206         if (strcmp(opt1, opt2) == 0)
  207                 return (1);
  208         /* "noopt" vs. "opt" */
  209         if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
  210                 return (1);
  211         /* "opt" vs. "noopt" */
  212         if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
  213                 return (1);
  214         while ((p = strchr(opt1, '.')) != NULL &&
  215             !strncmp(opt1, opt2, ++p - opt1)) {
  216                 opt2 += p - opt1;
  217                 opt1 = p;
  218                 /* "foo.noopt" vs. "foo.opt" */
  219                 if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
  220                         return (1);
  221                 /* "foo.opt" vs. "foo.noopt" */
  222                 if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
  223                         return (1);
  224         }
  225         /* "ro" / "rdonly" / "norw" / "rw" / "noro" */
  226         if ((vfs_isopt_ro(opt1) || vfs_isopt_rw(opt1)) &&
  227             (vfs_isopt_ro(opt2) || vfs_isopt_rw(opt2)))
  228                 return (1);
  229         return (0);
  230 }
  231 
  232 /*
  233  * If a mount option is specified several times,
  234  * (with or without the "no" prefix) only keep
  235  * the last occurrence of it.
  236  */
  237 static void
  238 vfs_sanitizeopts(struct vfsoptlist *opts)
  239 {
  240         struct vfsopt *opt, *opt2, *tmp;
  241 
  242         TAILQ_FOREACH_REVERSE(opt, opts, vfsoptlist, link) {
  243                 opt2 = TAILQ_PREV(opt, vfsoptlist, link);
  244                 while (opt2 != NULL) {
  245                         if (vfs_equalopts(opt->name, opt2->name)) {
  246                                 tmp = TAILQ_PREV(opt2, vfsoptlist, link);
  247                                 vfs_freeopt(opts, opt2);
  248                                 opt2 = tmp;
  249                         } else {
  250                                 opt2 = TAILQ_PREV(opt2, vfsoptlist, link);
  251                         }
  252                 }
  253         }
  254 }
  255 
  256 /*
  257  * Build a linked list of mount options from a struct uio.
  258  */
  259 int
  260 vfs_buildopts(struct uio *auio, struct vfsoptlist **options)
  261 {
  262         struct vfsoptlist *opts;
  263         struct vfsopt *opt;
  264         size_t memused, namelen, optlen;
  265         unsigned int i, iovcnt;
  266         int error;
  267 
  268         opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
  269         TAILQ_INIT(opts);
  270         memused = 0;
  271         iovcnt = auio->uio_iovcnt;
  272         for (i = 0; i < iovcnt; i += 2) {
  273                 namelen = auio->uio_iov[i].iov_len;
  274                 optlen = auio->uio_iov[i + 1].iov_len;
  275                 memused += sizeof(struct vfsopt) + optlen + namelen;
  276                 /*
  277                  * Avoid consuming too much memory, and attempts to overflow
  278                  * memused.
  279                  */
  280                 if (memused > VFS_MOUNTARG_SIZE_MAX ||
  281                     optlen > VFS_MOUNTARG_SIZE_MAX ||
  282                     namelen > VFS_MOUNTARG_SIZE_MAX) {
  283                         error = EINVAL;
  284                         goto bad;
  285                 }
  286 
  287                 opt = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
  288                 opt->name = malloc(namelen, M_MOUNT, M_WAITOK);
  289                 opt->value = NULL;
  290                 opt->len = 0;
  291                 opt->pos = i / 2;
  292                 opt->seen = 0;
  293 
  294                 /*
  295                  * Do this early, so jumps to "bad" will free the current
  296                  * option.
  297                  */
  298                 TAILQ_INSERT_TAIL(opts, opt, link);
  299 
  300                 if (auio->uio_segflg == UIO_SYSSPACE) {
  301                         bcopy(auio->uio_iov[i].iov_base, opt->name, namelen);
  302                 } else {
  303                         error = copyin(auio->uio_iov[i].iov_base, opt->name,
  304                             namelen);
  305                         if (error)
  306                                 goto bad;
  307                 }
  308                 /* Ensure names are null-terminated strings. */
  309                 if (namelen == 0 || opt->name[namelen - 1] != '\0') {
  310                         error = EINVAL;
  311                         goto bad;
  312                 }
  313                 if (optlen != 0) {
  314                         opt->len = optlen;
  315                         opt->value = malloc(optlen, M_MOUNT, M_WAITOK);
  316                         if (auio->uio_segflg == UIO_SYSSPACE) {
  317                                 bcopy(auio->uio_iov[i + 1].iov_base, opt->value,
  318                                     optlen);
  319                         } else {
  320                                 error = copyin(auio->uio_iov[i + 1].iov_base,
  321                                     opt->value, optlen);
  322                                 if (error)
  323                                         goto bad;
  324                         }
  325                 }
  326         }
  327         vfs_sanitizeopts(opts);
  328         *options = opts;
  329         return (0);
  330 bad:
  331         vfs_freeopts(opts);
  332         return (error);
  333 }
  334 
  335 /*
  336  * Merge the old mount options with the new ones passed
  337  * in the MNT_UPDATE case.
  338  *
  339  * XXX: This function will keep a "nofoo" option in the new
  340  * options.  E.g, if the option's canonical name is "foo",
  341  * "nofoo" ends up in the mount point's active options.
  342  */
  343 static void
  344 vfs_mergeopts(struct vfsoptlist *toopts, struct vfsoptlist *oldopts)
  345 {
  346         struct vfsopt *opt, *new;
  347 
  348         TAILQ_FOREACH(opt, oldopts, link) {
  349                 new = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
  350                 new->name = strdup(opt->name, M_MOUNT);
  351                 if (opt->len != 0) {
  352                         new->value = malloc(opt->len, M_MOUNT, M_WAITOK);
  353                         bcopy(opt->value, new->value, opt->len);
  354                 } else
  355                         new->value = NULL;
  356                 new->len = opt->len;
  357                 new->seen = opt->seen;
  358                 TAILQ_INSERT_HEAD(toopts, new, link);
  359         }
  360         vfs_sanitizeopts(toopts);
  361 }
  362 
  363 /*
  364  * Mount a filesystem.
  365  */
  366 int
  367 sys_nmount(td, uap)
  368         struct thread *td;
  369         struct nmount_args /* {
  370                 struct iovec *iovp;
  371                 unsigned int iovcnt;
  372                 int flags;
  373         } */ *uap;
  374 {
  375         struct uio *auio;
  376         int error;
  377         u_int iovcnt;
  378         uint64_t flags;
  379 
  380         /*
  381          * Mount flags are now 64-bits. On 32-bit archtectures only
  382          * 32-bits are passed in, but from here on everything handles
  383          * 64-bit flags correctly.
  384          */
  385         flags = uap->flags;
  386 
  387         AUDIT_ARG_FFLAGS(flags);
  388         CTR4(KTR_VFS, "%s: iovp %p with iovcnt %d and flags %d", __func__,
  389             uap->iovp, uap->iovcnt, flags);
  390 
  391         /*
  392          * Filter out MNT_ROOTFS.  We do not want clients of nmount() in
  393          * userspace to set this flag, but we must filter it out if we want
  394          * MNT_UPDATE on the root file system to work.
  395          * MNT_ROOTFS should only be set by the kernel when mounting its
  396          * root file system.
  397          */
  398         flags &= ~MNT_ROOTFS;
  399 
  400         iovcnt = uap->iovcnt;
  401         /*
  402          * Check that we have an even number of iovec's
  403          * and that we have at least two options.
  404          */
  405         if ((iovcnt & 1) || (iovcnt < 4)) {
  406                 CTR2(KTR_VFS, "%s: failed for invalid iovcnt %d", __func__,
  407                     uap->iovcnt);
  408                 return (EINVAL);
  409         }
  410 
  411         error = copyinuio(uap->iovp, iovcnt, &auio);
  412         if (error) {
  413                 CTR2(KTR_VFS, "%s: failed for invalid uio op with %d errno",
  414                     __func__, error);
  415                 return (error);
  416         }
  417         error = vfs_donmount(td, flags, auio);
  418 
  419         free(auio, M_IOV);
  420         return (error);
  421 }
  422 
  423 /*
  424  * ---------------------------------------------------------------------
  425  * Various utility functions
  426  */
  427 
  428 void
  429 vfs_ref(struct mount *mp)
  430 {
  431 
  432         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  433         MNT_ILOCK(mp);
  434         MNT_REF(mp);
  435         MNT_IUNLOCK(mp);
  436 }
  437 
  438 void
  439 vfs_rel(struct mount *mp)
  440 {
  441 
  442         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  443         MNT_ILOCK(mp);
  444         MNT_REL(mp);
  445         MNT_IUNLOCK(mp);
  446 }
  447 
  448 /*
  449  * Allocate and initialize the mount point struct.
  450  */
  451 struct mount *
  452 vfs_mount_alloc(struct vnode *vp, struct vfsconf *vfsp, const char *fspath,
  453     struct ucred *cred)
  454 {
  455         struct mount *mp;
  456 
  457         mp = uma_zalloc(mount_zone, M_WAITOK);
  458         bzero(&mp->mnt_startzero,
  459             __rangeof(struct mount, mnt_startzero, mnt_endzero));
  460         TAILQ_INIT(&mp->mnt_nvnodelist);
  461         mp->mnt_nvnodelistsize = 0;
  462         TAILQ_INIT(&mp->mnt_activevnodelist);
  463         mp->mnt_activevnodelistsize = 0;
  464         mp->mnt_ref = 0;
  465         (void) vfs_busy(mp, MBF_NOWAIT);
  466         atomic_add_acq_int(&vfsp->vfc_refcount, 1);
  467         mp->mnt_op = vfsp->vfc_vfsops;
  468         mp->mnt_vfc = vfsp;
  469         mp->mnt_stat.f_type = vfsp->vfc_typenum;
  470         mp->mnt_gen++;
  471         strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
  472         mp->mnt_vnodecovered = vp;
  473         mp->mnt_cred = crdup(cred);
  474         mp->mnt_stat.f_owner = cred->cr_uid;
  475         strlcpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
  476         mp->mnt_iosize_max = DFLTPHYS;
  477 #ifdef MAC
  478         mac_mount_init(mp);
  479         mac_mount_create(cred, mp);
  480 #endif
  481         arc4rand(&mp->mnt_hashseed, sizeof mp->mnt_hashseed, 0);
  482         TAILQ_INIT(&mp->mnt_uppers);
  483         return (mp);
  484 }
  485 
  486 /*
  487  * Destroy the mount struct previously allocated by vfs_mount_alloc().
  488  */
  489 void
  490 vfs_mount_destroy(struct mount *mp)
  491 {
  492 
  493         MNT_ILOCK(mp);
  494         mp->mnt_kern_flag |= MNTK_REFEXPIRE;
  495         if (mp->mnt_kern_flag & MNTK_MWAIT) {
  496                 mp->mnt_kern_flag &= ~MNTK_MWAIT;
  497                 wakeup(mp);
  498         }
  499         while (mp->mnt_ref)
  500                 msleep(mp, MNT_MTX(mp), PVFS, "mntref", 0);
  501         KASSERT(mp->mnt_ref == 0,
  502             ("%s: invalid refcount in the drain path @ %s:%d", __func__,
  503             __FILE__, __LINE__));
  504         if (mp->mnt_writeopcount != 0)
  505                 panic("vfs_mount_destroy: nonzero writeopcount");
  506         if (mp->mnt_secondary_writes != 0)
  507                 panic("vfs_mount_destroy: nonzero secondary_writes");
  508         atomic_subtract_rel_int(&mp->mnt_vfc->vfc_refcount, 1);
  509         if (!TAILQ_EMPTY(&mp->mnt_nvnodelist)) {
  510                 struct vnode *vp;
  511 
  512                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes)
  513                         vprint("", vp);
  514                 panic("unmount: dangling vnode");
  515         }
  516         KASSERT(TAILQ_EMPTY(&mp->mnt_uppers), ("mnt_uppers"));
  517         if (mp->mnt_nvnodelistsize != 0)
  518                 panic("vfs_mount_destroy: nonzero nvnodelistsize");
  519         if (mp->mnt_activevnodelistsize != 0)
  520                 panic("vfs_mount_destroy: nonzero activevnodelistsize");
  521         if (mp->mnt_lockref != 0)
  522                 panic("vfs_mount_destroy: nonzero lock refcount");
  523         MNT_IUNLOCK(mp);
  524 #ifdef MAC
  525         mac_mount_destroy(mp);
  526 #endif
  527         if (mp->mnt_opt != NULL)
  528                 vfs_freeopts(mp->mnt_opt);
  529         crfree(mp->mnt_cred);
  530         uma_zfree(mount_zone, mp);
  531 }
  532 
  533 int
  534 vfs_donmount(struct thread *td, uint64_t fsflags, struct uio *fsoptions)
  535 {
  536         struct vfsoptlist *optlist;
  537         struct vfsopt *opt, *tmp_opt;
  538         char *fstype, *fspath, *errmsg;
  539         int error, fstypelen, fspathlen, errmsg_len, errmsg_pos;
  540 
  541         errmsg = fspath = NULL;
  542         errmsg_len = fspathlen = 0;
  543         errmsg_pos = -1;
  544 
  545         error = vfs_buildopts(fsoptions, &optlist);
  546         if (error)
  547                 return (error);
  548 
  549         if (vfs_getopt(optlist, "errmsg", (void **)&errmsg, &errmsg_len) == 0)
  550                 errmsg_pos = vfs_getopt_pos(optlist, "errmsg");
  551 
  552         /*
  553          * We need these two options before the others,
  554          * and they are mandatory for any filesystem.
  555          * Ensure they are NUL terminated as well.
  556          */
  557         fstypelen = 0;
  558         error = vfs_getopt(optlist, "fstype", (void **)&fstype, &fstypelen);
  559         if (error || fstype[fstypelen - 1] != '\0') {
  560                 error = EINVAL;
  561                 if (errmsg != NULL)
  562                         strncpy(errmsg, "Invalid fstype", errmsg_len);
  563                 goto bail;
  564         }
  565         fspathlen = 0;
  566         error = vfs_getopt(optlist, "fspath", (void **)&fspath, &fspathlen);
  567         if (error || fspath[fspathlen - 1] != '\0') {
  568                 error = EINVAL;
  569                 if (errmsg != NULL)
  570                         strncpy(errmsg, "Invalid fspath", errmsg_len);
  571                 goto bail;
  572         }
  573 
  574         /*
  575          * We need to see if we have the "update" option
  576          * before we call vfs_domount(), since vfs_domount() has special
  577          * logic based on MNT_UPDATE.  This is very important
  578          * when we want to update the root filesystem.
  579          */
  580         TAILQ_FOREACH_SAFE(opt, optlist, link, tmp_opt) {
  581                 if (strcmp(opt->name, "update") == 0) {
  582                         fsflags |= MNT_UPDATE;
  583                         vfs_freeopt(optlist, opt);
  584                 }
  585                 else if (strcmp(opt->name, "async") == 0)
  586                         fsflags |= MNT_ASYNC;
  587                 else if (strcmp(opt->name, "force") == 0) {
  588                         fsflags |= MNT_FORCE;
  589                         vfs_freeopt(optlist, opt);
  590                 }
  591                 else if (strcmp(opt->name, "reload") == 0) {
  592                         fsflags |= MNT_RELOAD;
  593                         vfs_freeopt(optlist, opt);
  594                 }
  595                 else if (strcmp(opt->name, "multilabel") == 0)
  596                         fsflags |= MNT_MULTILABEL;
  597                 else if (strcmp(opt->name, "noasync") == 0)
  598                         fsflags &= ~MNT_ASYNC;
  599                 else if (strcmp(opt->name, "noatime") == 0)
  600                         fsflags |= MNT_NOATIME;
  601                 else if (strcmp(opt->name, "atime") == 0) {
  602                         free(opt->name, M_MOUNT);
  603                         opt->name = strdup("nonoatime", M_MOUNT);
  604                 }
  605                 else if (strcmp(opt->name, "noclusterr") == 0)
  606                         fsflags |= MNT_NOCLUSTERR;
  607                 else if (strcmp(opt->name, "clusterr") == 0) {
  608                         free(opt->name, M_MOUNT);
  609                         opt->name = strdup("nonoclusterr", M_MOUNT);
  610                 }
  611                 else if (strcmp(opt->name, "noclusterw") == 0)
  612                         fsflags |= MNT_NOCLUSTERW;
  613                 else if (strcmp(opt->name, "clusterw") == 0) {
  614                         free(opt->name, M_MOUNT);
  615                         opt->name = strdup("nonoclusterw", M_MOUNT);
  616                 }
  617                 else if (strcmp(opt->name, "noexec") == 0)
  618                         fsflags |= MNT_NOEXEC;
  619                 else if (strcmp(opt->name, "exec") == 0) {
  620                         free(opt->name, M_MOUNT);
  621                         opt->name = strdup("nonoexec", M_MOUNT);
  622                 }
  623                 else if (strcmp(opt->name, "nosuid") == 0)
  624                         fsflags |= MNT_NOSUID;
  625                 else if (strcmp(opt->name, "suid") == 0) {
  626                         free(opt->name, M_MOUNT);
  627                         opt->name = strdup("nonosuid", M_MOUNT);
  628                 }
  629                 else if (strcmp(opt->name, "nosymfollow") == 0)
  630                         fsflags |= MNT_NOSYMFOLLOW;
  631                 else if (strcmp(opt->name, "symfollow") == 0) {
  632                         free(opt->name, M_MOUNT);
  633                         opt->name = strdup("nonosymfollow", M_MOUNT);
  634                 }
  635                 else if (strcmp(opt->name, "noro") == 0)
  636                         fsflags &= ~MNT_RDONLY;
  637                 else if (strcmp(opt->name, "rw") == 0)
  638                         fsflags &= ~MNT_RDONLY;
  639                 else if (strcmp(opt->name, "ro") == 0)
  640                         fsflags |= MNT_RDONLY;
  641                 else if (strcmp(opt->name, "rdonly") == 0) {
  642                         free(opt->name, M_MOUNT);
  643                         opt->name = strdup("ro", M_MOUNT);
  644                         fsflags |= MNT_RDONLY;
  645                 }
  646                 else if (strcmp(opt->name, "suiddir") == 0)
  647                         fsflags |= MNT_SUIDDIR;
  648                 else if (strcmp(opt->name, "sync") == 0)
  649                         fsflags |= MNT_SYNCHRONOUS;
  650                 else if (strcmp(opt->name, "union") == 0)
  651                         fsflags |= MNT_UNION;
  652                 else if (strcmp(opt->name, "automounted") == 0) {
  653                         fsflags |= MNT_AUTOMOUNTED;
  654                         vfs_freeopt(optlist, opt);
  655                 }
  656         }
  657 
  658         /*
  659          * Be ultra-paranoid about making sure the type and fspath
  660          * variables will fit in our mp buffers, including the
  661          * terminating NUL.
  662          */
  663         if (fstypelen > MFSNAMELEN || fspathlen > MNAMELEN) {
  664                 error = ENAMETOOLONG;
  665                 goto bail;
  666         }
  667 
  668         error = vfs_domount(td, fstype, fspath, fsflags, &optlist);
  669 bail:
  670         /* copyout the errmsg */
  671         if (errmsg_pos != -1 && ((2 * errmsg_pos + 1) < fsoptions->uio_iovcnt)
  672             && errmsg_len > 0 && errmsg != NULL) {
  673                 if (fsoptions->uio_segflg == UIO_SYSSPACE) {
  674                         bcopy(errmsg,
  675                             fsoptions->uio_iov[2 * errmsg_pos + 1].iov_base,
  676                             fsoptions->uio_iov[2 * errmsg_pos + 1].iov_len);
  677                 } else {
  678                         copyout(errmsg,
  679                             fsoptions->uio_iov[2 * errmsg_pos + 1].iov_base,
  680                             fsoptions->uio_iov[2 * errmsg_pos + 1].iov_len);
  681                 }
  682         }
  683 
  684         if (optlist != NULL)
  685                 vfs_freeopts(optlist);
  686         return (error);
  687 }
  688 
  689 /*
  690  * Old mount API.
  691  */
  692 #ifndef _SYS_SYSPROTO_H_
  693 struct mount_args {
  694         char    *type;
  695         char    *path;
  696         int     flags;
  697         caddr_t data;
  698 };
  699 #endif
  700 /* ARGSUSED */
  701 int
  702 sys_mount(td, uap)
  703         struct thread *td;
  704         struct mount_args /* {
  705                 char *type;
  706                 char *path;
  707                 int flags;
  708                 caddr_t data;
  709         } */ *uap;
  710 {
  711         char *fstype;
  712         struct vfsconf *vfsp = NULL;
  713         struct mntarg *ma = NULL;
  714         uint64_t flags;
  715         int error;
  716 
  717         /*
  718          * Mount flags are now 64-bits. On 32-bit architectures only
  719          * 32-bits are passed in, but from here on everything handles
  720          * 64-bit flags correctly.
  721          */
  722         flags = uap->flags;
  723 
  724         AUDIT_ARG_FFLAGS(flags);
  725 
  726         /*
  727          * Filter out MNT_ROOTFS.  We do not want clients of mount() in
  728          * userspace to set this flag, but we must filter it out if we want
  729          * MNT_UPDATE on the root file system to work.
  730          * MNT_ROOTFS should only be set by the kernel when mounting its
  731          * root file system.
  732          */
  733         flags &= ~MNT_ROOTFS;
  734 
  735         fstype = malloc(MFSNAMELEN, M_TEMP, M_WAITOK);
  736         error = copyinstr(uap->type, fstype, MFSNAMELEN, NULL);
  737         if (error) {
  738                 free(fstype, M_TEMP);
  739                 return (error);
  740         }
  741 
  742         AUDIT_ARG_TEXT(fstype);
  743         vfsp = vfs_byname_kld(fstype, td, &error);
  744         free(fstype, M_TEMP);
  745         if (vfsp == NULL)
  746                 return (ENOENT);
  747         if (vfsp->vfc_vfsops->vfs_cmount == NULL)
  748                 return (EOPNOTSUPP);
  749 
  750         ma = mount_argsu(ma, "fstype", uap->type, MFSNAMELEN);
  751         ma = mount_argsu(ma, "fspath", uap->path, MNAMELEN);
  752         ma = mount_argb(ma, flags & MNT_RDONLY, "noro");
  753         ma = mount_argb(ma, !(flags & MNT_NOSUID), "nosuid");
  754         ma = mount_argb(ma, !(flags & MNT_NOEXEC), "noexec");
  755 
  756         error = vfsp->vfc_vfsops->vfs_cmount(ma, uap->data, flags);
  757         return (error);
  758 }
  759 
  760 /*
  761  * vfs_domount_first(): first file system mount (not update)
  762  */
  763 static int
  764 vfs_domount_first(
  765         struct thread *td,              /* Calling thread. */
  766         struct vfsconf *vfsp,           /* File system type. */
  767         char *fspath,                   /* Mount path. */
  768         struct vnode *vp,               /* Vnode to be covered. */
  769         uint64_t fsflags,               /* Flags common to all filesystems. */
  770         struct vfsoptlist **optlist     /* Options local to the filesystem. */
  771         )
  772 {
  773         struct vattr va;
  774         struct mount *mp;
  775         struct vnode *newdp;
  776         int error;
  777 
  778         ASSERT_VOP_ELOCKED(vp, __func__);
  779         KASSERT((fsflags & MNT_UPDATE) == 0, ("MNT_UPDATE shouldn't be here"));
  780 
  781         /*
  782          * If the user is not root, ensure that they own the directory
  783          * onto which we are attempting to mount.
  784          */
  785         error = VOP_GETATTR(vp, &va, td->td_ucred);
  786         if (error == 0 && va.va_uid != td->td_ucred->cr_uid)
  787                 error = priv_check_cred(td->td_ucred, PRIV_VFS_ADMIN, 0);
  788         if (error == 0)
  789                 error = vinvalbuf(vp, V_SAVE, 0, 0);
  790         if (error == 0 && vp->v_type != VDIR)
  791                 error = ENOTDIR;
  792         if (error == 0) {
  793                 VI_LOCK(vp);
  794                 if ((vp->v_iflag & VI_MOUNT) == 0 && vp->v_mountedhere == NULL)
  795                         vp->v_iflag |= VI_MOUNT;
  796                 else
  797                         error = EBUSY;
  798                 VI_UNLOCK(vp);
  799         }
  800         if (error != 0) {
  801                 vput(vp);
  802                 return (error);
  803         }
  804         VOP_UNLOCK(vp, 0);
  805 
  806         /* Allocate and initialize the filesystem. */
  807         mp = vfs_mount_alloc(vp, vfsp, fspath, td->td_ucred);
  808         /* XXXMAC: pass to vfs_mount_alloc? */
  809         mp->mnt_optnew = *optlist;
  810         /* Set the mount level flags. */
  811         mp->mnt_flag = (fsflags & (MNT_UPDATEMASK | MNT_ROOTFS | MNT_RDONLY));
  812 
  813         /*
  814          * Mount the filesystem.
  815          * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
  816          * get.  No freeing of cn_pnbuf.
  817          */
  818         error = VFS_MOUNT(mp);
  819         if (error != 0) {
  820                 vfs_unbusy(mp);
  821                 vfs_mount_destroy(mp);
  822                 VI_LOCK(vp);
  823                 vp->v_iflag &= ~VI_MOUNT;
  824                 VI_UNLOCK(vp);
  825                 vrele(vp);
  826                 return (error);
  827         }
  828 
  829         if (mp->mnt_opt != NULL)
  830                 vfs_freeopts(mp->mnt_opt);
  831         mp->mnt_opt = mp->mnt_optnew;
  832         *optlist = NULL;
  833         (void)VFS_STATFS(mp, &mp->mnt_stat);
  834 
  835         /*
  836          * Prevent external consumers of mount options from reading mnt_optnew.
  837          */
  838         mp->mnt_optnew = NULL;
  839 
  840         MNT_ILOCK(mp);
  841         if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
  842             (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
  843                 mp->mnt_kern_flag |= MNTK_ASYNC;
  844         else
  845                 mp->mnt_kern_flag &= ~MNTK_ASYNC;
  846         MNT_IUNLOCK(mp);
  847 
  848         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
  849         cache_purge(vp);
  850         VI_LOCK(vp);
  851         vp->v_iflag &= ~VI_MOUNT;
  852         VI_UNLOCK(vp);
  853         vp->v_mountedhere = mp;
  854         /* Place the new filesystem at the end of the mount list. */
  855         mtx_lock(&mountlist_mtx);
  856         TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
  857         mtx_unlock(&mountlist_mtx);
  858         vfs_event_signal(NULL, VQ_MOUNT, 0);
  859         if (VFS_ROOT(mp, LK_EXCLUSIVE, &newdp))
  860                 panic("mount: lost mount");
  861         VOP_UNLOCK(vp, 0);
  862         EVENTHANDLER_INVOKE(vfs_mounted, mp, newdp, td);
  863         VOP_UNLOCK(newdp, 0);
  864         mountcheckdirs(vp, newdp);
  865         vrele(newdp);
  866         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  867                 vfs_allocate_syncvnode(mp);
  868         vfs_unbusy(mp);
  869         return (0);
  870 }
  871 
  872 /*
  873  * vfs_domount_update(): update of mounted file system
  874  */
  875 static int
  876 vfs_domount_update(
  877         struct thread *td,              /* Calling thread. */
  878         struct vnode *vp,               /* Mount point vnode. */
  879         uint64_t fsflags,               /* Flags common to all filesystems. */
  880         struct vfsoptlist **optlist     /* Options local to the filesystem. */
  881         )
  882 {
  883         struct oexport_args oexport;
  884         struct export_args export;
  885         struct mount *mp;
  886         int error, export_error;
  887         uint64_t flag;
  888 
  889         ASSERT_VOP_ELOCKED(vp, __func__);
  890         KASSERT((fsflags & MNT_UPDATE) != 0, ("MNT_UPDATE should be here"));
  891         mp = vp->v_mount;
  892 
  893         if ((vp->v_vflag & VV_ROOT) == 0) {
  894                 if (vfs_copyopt(*optlist, "export", &export, sizeof(export))
  895                     == 0)
  896                         error = EXDEV;
  897                 else
  898                         error = EINVAL;
  899                 vput(vp);
  900                 return (error);
  901         }
  902 
  903         /*
  904          * We only allow the filesystem to be reloaded if it
  905          * is currently mounted read-only.
  906          */
  907         flag = mp->mnt_flag;
  908         if ((fsflags & MNT_RELOAD) != 0 && (flag & MNT_RDONLY) == 0) {
  909                 vput(vp);
  910                 return (EOPNOTSUPP);    /* Needs translation */
  911         }
  912         /*
  913          * Only privileged root, or (if MNT_USER is set) the user that
  914          * did the original mount is permitted to update it.
  915          */
  916         error = vfs_suser(mp, td);
  917         if (error != 0) {
  918                 vput(vp);
  919                 return (error);
  920         }
  921         if (vfs_busy(mp, MBF_NOWAIT)) {
  922                 vput(vp);
  923                 return (EBUSY);
  924         }
  925         VI_LOCK(vp);
  926         if ((vp->v_iflag & VI_MOUNT) != 0 || vp->v_mountedhere != NULL) {
  927                 VI_UNLOCK(vp);
  928                 vfs_unbusy(mp);
  929                 vput(vp);
  930                 return (EBUSY);
  931         }
  932         vp->v_iflag |= VI_MOUNT;
  933         VI_UNLOCK(vp);
  934         VOP_UNLOCK(vp, 0);
  935 
  936         MNT_ILOCK(mp);
  937         if ((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
  938                 MNT_IUNLOCK(mp);
  939                 error = EBUSY;
  940                 goto end;
  941         }
  942         mp->mnt_flag &= ~MNT_UPDATEMASK;
  943         mp->mnt_flag |= fsflags & (MNT_RELOAD | MNT_FORCE | MNT_UPDATE |
  944             MNT_SNAPSHOT | MNT_ROOTFS | MNT_UPDATEMASK | MNT_RDONLY);
  945         if ((mp->mnt_flag & MNT_ASYNC) == 0)
  946                 mp->mnt_kern_flag &= ~MNTK_ASYNC;
  947         MNT_IUNLOCK(mp);
  948         mp->mnt_optnew = *optlist;
  949         vfs_mergeopts(mp->mnt_optnew, mp->mnt_opt);
  950 
  951         /*
  952          * Mount the filesystem.
  953          * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
  954          * get.  No freeing of cn_pnbuf.
  955          */
  956         error = VFS_MOUNT(mp);
  957 
  958         export_error = 0;
  959         if (error == 0) {
  960                 /* Process the export option. */
  961                 if (vfs_copyopt(mp->mnt_optnew, "export", &export,
  962                     sizeof(export)) == 0) {
  963                         export_error = vfs_export(mp, &export);
  964                 } else if (vfs_copyopt(mp->mnt_optnew, "export", &oexport,
  965                     sizeof(oexport)) == 0) {
  966                         export.ex_flags = oexport.ex_flags;
  967                         export.ex_root = oexport.ex_root;
  968                         export.ex_anon = oexport.ex_anon;
  969                         export.ex_addr = oexport.ex_addr;
  970                         export.ex_addrlen = oexport.ex_addrlen;
  971                         export.ex_mask = oexport.ex_mask;
  972                         export.ex_masklen = oexport.ex_masklen;
  973                         export.ex_indexfile = oexport.ex_indexfile;
  974                         export.ex_numsecflavors = 0;
  975                         export_error = vfs_export(mp, &export);
  976                 }
  977         }
  978 
  979         MNT_ILOCK(mp);
  980         if (error == 0) {
  981                 mp->mnt_flag &= ~(MNT_UPDATE | MNT_RELOAD | MNT_FORCE |
  982                     MNT_SNAPSHOT);
  983         } else {
  984                 /*
  985                  * If we fail, restore old mount flags. MNT_QUOTA is special,
  986                  * because it is not part of MNT_UPDATEMASK, but it could have
  987                  * changed in the meantime if quotactl(2) was called.
  988                  * All in all we want current value of MNT_QUOTA, not the old
  989                  * one.
  990                  */
  991                 mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA);
  992         }
  993         if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
  994             (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
  995                 mp->mnt_kern_flag |= MNTK_ASYNC;
  996         else
  997                 mp->mnt_kern_flag &= ~MNTK_ASYNC;
  998         MNT_IUNLOCK(mp);
  999 
 1000         if (error != 0)
 1001                 goto end;
 1002 
 1003         if (mp->mnt_opt != NULL)
 1004                 vfs_freeopts(mp->mnt_opt);
 1005         mp->mnt_opt = mp->mnt_optnew;
 1006         *optlist = NULL;
 1007         (void)VFS_STATFS(mp, &mp->mnt_stat);
 1008         /*
 1009          * Prevent external consumers of mount options from reading
 1010          * mnt_optnew.
 1011          */
 1012         mp->mnt_optnew = NULL;
 1013 
 1014         if ((mp->mnt_flag & MNT_RDONLY) == 0)
 1015                 vfs_allocate_syncvnode(mp);
 1016         else
 1017                 vfs_deallocate_syncvnode(mp);
 1018 end:
 1019         vfs_unbusy(mp);
 1020         VI_LOCK(vp);
 1021         vp->v_iflag &= ~VI_MOUNT;
 1022         VI_UNLOCK(vp);
 1023         vrele(vp);
 1024         return (error != 0 ? error : export_error);
 1025 }
 1026 
 1027 /*
 1028  * vfs_domount(): actually attempt a filesystem mount.
 1029  */
 1030 static int
 1031 vfs_domount(
 1032         struct thread *td,              /* Calling thread. */
 1033         const char *fstype,             /* Filesystem type. */
 1034         char *fspath,                   /* Mount path. */
 1035         uint64_t fsflags,               /* Flags common to all filesystems. */
 1036         struct vfsoptlist **optlist     /* Options local to the filesystem. */
 1037         )
 1038 {
 1039         struct vfsconf *vfsp;
 1040         struct nameidata nd;
 1041         struct vnode *vp;
 1042         char *pathbuf;
 1043         int error;
 1044 
 1045         /*
 1046          * Be ultra-paranoid about making sure the type and fspath
 1047          * variables will fit in our mp buffers, including the
 1048          * terminating NUL.
 1049          */
 1050         if (strlen(fstype) >= MFSNAMELEN || strlen(fspath) >= MNAMELEN)
 1051                 return (ENAMETOOLONG);
 1052 
 1053         if (jailed(td->td_ucred) || usermount == 0) {
 1054                 if ((error = priv_check(td, PRIV_VFS_MOUNT)) != 0)
 1055                         return (error);
 1056         }
 1057 
 1058         /*
 1059          * Do not allow NFS export or MNT_SUIDDIR by unprivileged users.
 1060          */
 1061         if (fsflags & MNT_EXPORTED) {
 1062                 error = priv_check(td, PRIV_VFS_MOUNT_EXPORTED);
 1063                 if (error)
 1064                         return (error);
 1065         }
 1066         if (fsflags & MNT_SUIDDIR) {
 1067                 error = priv_check(td, PRIV_VFS_MOUNT_SUIDDIR);
 1068                 if (error)
 1069                         return (error);
 1070         }
 1071         /*
 1072          * Silently enforce MNT_NOSUID and MNT_USER for unprivileged users.
 1073          */
 1074         if ((fsflags & (MNT_NOSUID | MNT_USER)) != (MNT_NOSUID | MNT_USER)) {
 1075                 if (priv_check(td, PRIV_VFS_MOUNT_NONUSER) != 0)
 1076                         fsflags |= MNT_NOSUID | MNT_USER;
 1077         }
 1078 
 1079         /* Load KLDs before we lock the covered vnode to avoid reversals. */
 1080         vfsp = NULL;
 1081         if ((fsflags & MNT_UPDATE) == 0) {
 1082                 /* Don't try to load KLDs if we're mounting the root. */
 1083                 if (fsflags & MNT_ROOTFS)
 1084                         vfsp = vfs_byname(fstype);
 1085                 else
 1086                         vfsp = vfs_byname_kld(fstype, td, &error);
 1087                 if (vfsp == NULL)
 1088                         return (ENODEV);
 1089                 if (jailed(td->td_ucred) && !(vfsp->vfc_flags & VFCF_JAIL))
 1090                         return (EPERM);
 1091         }
 1092 
 1093         /*
 1094          * Get vnode to be covered or mount point's vnode in case of MNT_UPDATE.
 1095          */
 1096         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1,
 1097             UIO_SYSSPACE, fspath, td);
 1098         error = namei(&nd);
 1099         if (error != 0)
 1100                 return (error);
 1101         NDFREE(&nd, NDF_ONLY_PNBUF);
 1102         vp = nd.ni_vp;
 1103         if ((fsflags & MNT_UPDATE) == 0) {
 1104                 pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
 1105                 strcpy(pathbuf, fspath);
 1106                 error = vn_path_to_global_path(td, vp, pathbuf, MNAMELEN);
 1107                 /* debug.disablefullpath == 1 results in ENODEV */
 1108                 if (error == 0 || error == ENODEV) {
 1109                         error = vfs_domount_first(td, vfsp, pathbuf, vp,
 1110                             fsflags, optlist);
 1111                 }
 1112                 free(pathbuf, M_TEMP);
 1113         } else
 1114                 error = vfs_domount_update(td, vp, fsflags, optlist);
 1115 
 1116         return (error);
 1117 }
 1118 
 1119 /*
 1120  * Unmount a filesystem.
 1121  *
 1122  * Note: unmount takes a path to the vnode mounted on as argument, not
 1123  * special file (as before).
 1124  */
 1125 #ifndef _SYS_SYSPROTO_H_
 1126 struct unmount_args {
 1127         char    *path;
 1128         int     flags;
 1129 };
 1130 #endif
 1131 /* ARGSUSED */
 1132 int
 1133 sys_unmount(struct thread *td, struct unmount_args *uap)
 1134 {
 1135         struct nameidata nd;
 1136         struct mount *mp;
 1137         char *pathbuf;
 1138         int error, id0, id1;
 1139 
 1140         AUDIT_ARG_VALUE(uap->flags);
 1141         if (jailed(td->td_ucred) || usermount == 0) {
 1142                 error = priv_check(td, PRIV_VFS_UNMOUNT);
 1143                 if (error)
 1144                         return (error);
 1145         }
 1146 
 1147         pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
 1148         error = copyinstr(uap->path, pathbuf, MNAMELEN, NULL);
 1149         if (error) {
 1150                 free(pathbuf, M_TEMP);
 1151                 return (error);
 1152         }
 1153         if (uap->flags & MNT_BYFSID) {
 1154                 AUDIT_ARG_TEXT(pathbuf);
 1155                 /* Decode the filesystem ID. */
 1156                 if (sscanf(pathbuf, "FSID:%d:%d", &id0, &id1) != 2) {
 1157                         free(pathbuf, M_TEMP);
 1158                         return (EINVAL);
 1159                 }
 1160 
 1161                 mtx_lock(&mountlist_mtx);
 1162                 TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
 1163                         if (mp->mnt_stat.f_fsid.val[0] == id0 &&
 1164                             mp->mnt_stat.f_fsid.val[1] == id1) {
 1165                                 vfs_ref(mp);
 1166                                 break;
 1167                         }
 1168                 }
 1169                 mtx_unlock(&mountlist_mtx);
 1170         } else {
 1171                 /*
 1172                  * Try to find global path for path argument.
 1173                  */
 1174                 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1,
 1175                     UIO_SYSSPACE, pathbuf, td);
 1176                 if (namei(&nd) == 0) {
 1177                         NDFREE(&nd, NDF_ONLY_PNBUF);
 1178                         error = vn_path_to_global_path(td, nd.ni_vp, pathbuf,
 1179                             MNAMELEN);
 1180                         if (error == 0 || error == ENODEV)
 1181                                 vput(nd.ni_vp);
 1182                 }
 1183                 mtx_lock(&mountlist_mtx);
 1184                 TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
 1185                         if (strcmp(mp->mnt_stat.f_mntonname, pathbuf) == 0) {
 1186                                 vfs_ref(mp);
 1187                                 break;
 1188                         }
 1189                 }
 1190                 mtx_unlock(&mountlist_mtx);
 1191         }
 1192         free(pathbuf, M_TEMP);
 1193         if (mp == NULL) {
 1194                 /*
 1195                  * Previously we returned ENOENT for a nonexistent path and
 1196                  * EINVAL for a non-mountpoint.  We cannot tell these apart
 1197                  * now, so in the !MNT_BYFSID case return the more likely
 1198                  * EINVAL for compatibility.
 1199                  */
 1200                 return ((uap->flags & MNT_BYFSID) ? ENOENT : EINVAL);
 1201         }
 1202 
 1203         /*
 1204          * Don't allow unmounting the root filesystem.
 1205          */
 1206         if (mp->mnt_flag & MNT_ROOTFS) {
 1207                 vfs_rel(mp);
 1208                 return (EINVAL);
 1209         }
 1210         error = dounmount(mp, uap->flags, td);
 1211         return (error);
 1212 }
 1213 
 1214 /*
 1215  * Do the actual filesystem unmount.
 1216  */
 1217 int
 1218 dounmount(struct mount *mp, int flags, struct thread *td)
 1219 {
 1220         struct vnode *coveredvp, *fsrootvp;
 1221         int error;
 1222         uint64_t async_flag;
 1223         int mnt_gen_r;
 1224 
 1225         if ((coveredvp = mp->mnt_vnodecovered) != NULL) {
 1226                 mnt_gen_r = mp->mnt_gen;
 1227                 VI_LOCK(coveredvp);
 1228                 vholdl(coveredvp);
 1229                 vn_lock(coveredvp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
 1230                 /*
 1231                  * Check for mp being unmounted while waiting for the
 1232                  * covered vnode lock.
 1233                  */
 1234                 if (coveredvp->v_mountedhere != mp ||
 1235                     coveredvp->v_mountedhere->mnt_gen != mnt_gen_r) {
 1236                         VOP_UNLOCK(coveredvp, 0);
 1237                         vdrop(coveredvp);
 1238                         vfs_rel(mp);
 1239                         return (EBUSY);
 1240                 }
 1241         }
 1242 
 1243         /*
 1244          * Only privileged root, or (if MNT_USER is set) the user that did the
 1245          * original mount is permitted to unmount this filesystem.
 1246          */
 1247         error = vfs_suser(mp, td);
 1248         if (error != 0) {
 1249                 if (coveredvp != NULL) {
 1250                         VOP_UNLOCK(coveredvp, 0);
 1251                         vdrop(coveredvp);
 1252                 }
 1253                 vfs_rel(mp);
 1254                 return (error);
 1255         }
 1256 
 1257         vn_start_write(NULL, &mp, V_WAIT | V_MNTREF);
 1258         MNT_ILOCK(mp);
 1259         if ((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0 ||
 1260             (mp->mnt_flag & MNT_UPDATE) != 0 ||
 1261             !TAILQ_EMPTY(&mp->mnt_uppers)) {
 1262                 MNT_IUNLOCK(mp);
 1263                 if (coveredvp != NULL) {
 1264                         VOP_UNLOCK(coveredvp, 0);
 1265                         vdrop(coveredvp);
 1266                 }
 1267                 vn_finished_write(mp);
 1268                 return (EBUSY);
 1269         }
 1270         mp->mnt_kern_flag |= MNTK_UNMOUNT | MNTK_NOINSMNTQ;
 1271         /* Allow filesystems to detect that a forced unmount is in progress. */
 1272         if (flags & MNT_FORCE) {
 1273                 mp->mnt_kern_flag |= MNTK_UNMOUNTF;
 1274                 MNT_IUNLOCK(mp);
 1275                 /*
 1276                  * Must be done after setting MNTK_UNMOUNTF and before
 1277                  * waiting for mnt_lockref to become 0.
 1278                  */
 1279                 VFS_PURGE(mp);
 1280                 MNT_ILOCK(mp);
 1281         }
 1282         error = 0;
 1283         if (mp->mnt_lockref) {
 1284                 mp->mnt_kern_flag |= MNTK_DRAINING;
 1285                 error = msleep(&mp->mnt_lockref, MNT_MTX(mp), PVFS,
 1286                     "mount drain", 0);
 1287         }
 1288         MNT_IUNLOCK(mp);
 1289         KASSERT(mp->mnt_lockref == 0,
 1290             ("%s: invalid lock refcount in the drain path @ %s:%d",
 1291             __func__, __FILE__, __LINE__));
 1292         KASSERT(error == 0,
 1293             ("%s: invalid return value for msleep in the drain path @ %s:%d",
 1294             __func__, __FILE__, __LINE__));
 1295 
 1296         if (mp->mnt_flag & MNT_EXPUBLIC)
 1297                 vfs_setpublicfs(NULL, NULL, NULL);
 1298 
 1299         /*
 1300          * From now, we can claim that the use reference on the
 1301          * coveredvp is ours, and the ref can be released only by
 1302          * successfull unmount by us, or left for later unmount
 1303          * attempt.  The previously acquired hold reference is no
 1304          * longer needed to protect the vnode from reuse.
 1305          */
 1306         if (coveredvp != NULL)
 1307                 vdrop(coveredvp);
 1308 
 1309         vfs_msync(mp, MNT_WAIT);
 1310         MNT_ILOCK(mp);
 1311         async_flag = mp->mnt_flag & MNT_ASYNC;
 1312         mp->mnt_flag &= ~MNT_ASYNC;
 1313         mp->mnt_kern_flag &= ~MNTK_ASYNC;
 1314         MNT_IUNLOCK(mp);
 1315         cache_purgevfs(mp);     /* remove cache entries for this file sys */
 1316         vfs_deallocate_syncvnode(mp);
 1317         /*
 1318          * For forced unmounts, move process cdir/rdir refs on the fs root
 1319          * vnode to the covered vnode.  For non-forced unmounts we want
 1320          * such references to cause an EBUSY error.
 1321          */
 1322         if ((flags & MNT_FORCE) &&
 1323             VFS_ROOT(mp, LK_EXCLUSIVE, &fsrootvp) == 0) {
 1324                 if (mp->mnt_vnodecovered != NULL &&
 1325                     (mp->mnt_flag & MNT_IGNORE) == 0)
 1326                         mountcheckdirs(fsrootvp, mp->mnt_vnodecovered);
 1327                 if (fsrootvp == rootvnode) {
 1328                         vrele(rootvnode);
 1329                         rootvnode = NULL;
 1330                 }
 1331                 vput(fsrootvp);
 1332         }
 1333         if ((mp->mnt_flag & MNT_RDONLY) != 0 || (flags & MNT_FORCE) != 0 ||
 1334             (error = VFS_SYNC(mp, MNT_WAIT)) == 0)
 1335                 error = VFS_UNMOUNT(mp, flags);
 1336         vn_finished_write(mp);
 1337         /*
 1338          * If we failed to flush the dirty blocks for this mount point,
 1339          * undo all the cdir/rdir and rootvnode changes we made above.
 1340          * Unless we failed to do so because the device is reporting that
 1341          * it doesn't exist anymore.
 1342          */
 1343         if (error && error != ENXIO) {
 1344                 if ((flags & MNT_FORCE) &&
 1345                     VFS_ROOT(mp, LK_EXCLUSIVE, &fsrootvp) == 0) {
 1346                         if (mp->mnt_vnodecovered != NULL &&
 1347                             (mp->mnt_flag & MNT_IGNORE) == 0)
 1348                                 mountcheckdirs(mp->mnt_vnodecovered, fsrootvp);
 1349                         if (rootvnode == NULL) {
 1350                                 rootvnode = fsrootvp;
 1351                                 vref(rootvnode);
 1352                         }
 1353                         vput(fsrootvp);
 1354                 }
 1355                 MNT_ILOCK(mp);
 1356                 mp->mnt_kern_flag &= ~MNTK_NOINSMNTQ;
 1357                 if ((mp->mnt_flag & MNT_RDONLY) == 0) {
 1358                         MNT_IUNLOCK(mp);
 1359                         vfs_allocate_syncvnode(mp);
 1360                         MNT_ILOCK(mp);
 1361                 }
 1362                 mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
 1363                 mp->mnt_flag |= async_flag;
 1364                 if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
 1365                     (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
 1366                         mp->mnt_kern_flag |= MNTK_ASYNC;
 1367                 if (mp->mnt_kern_flag & MNTK_MWAIT) {
 1368                         mp->mnt_kern_flag &= ~MNTK_MWAIT;
 1369                         wakeup(mp);
 1370                 }
 1371                 MNT_IUNLOCK(mp);
 1372                 if (coveredvp)
 1373                         VOP_UNLOCK(coveredvp, 0);
 1374                 return (error);
 1375         }
 1376         mtx_lock(&mountlist_mtx);
 1377         TAILQ_REMOVE(&mountlist, mp, mnt_list);
 1378         mtx_unlock(&mountlist_mtx);
 1379         EVENTHANDLER_INVOKE(vfs_unmounted, mp, td);
 1380         if (coveredvp != NULL) {
 1381                 coveredvp->v_mountedhere = NULL;
 1382                 vput(coveredvp);
 1383         }
 1384         vfs_event_signal(NULL, VQ_UNMOUNT, 0);
 1385         if (mp == rootdevmp)
 1386                 rootdevmp = NULL;
 1387         vfs_mount_destroy(mp);
 1388         return (0);
 1389 }
 1390 
 1391 /*
 1392  * Report errors during filesystem mounting.
 1393  */
 1394 void
 1395 vfs_mount_error(struct mount *mp, const char *fmt, ...)
 1396 {
 1397         struct vfsoptlist *moptlist = mp->mnt_optnew;
 1398         va_list ap;
 1399         int error, len;
 1400         char *errmsg;
 1401 
 1402         error = vfs_getopt(moptlist, "errmsg", (void **)&errmsg, &len);
 1403         if (error || errmsg == NULL || len <= 0)
 1404                 return;
 1405 
 1406         va_start(ap, fmt);
 1407         vsnprintf(errmsg, (size_t)len, fmt, ap);
 1408         va_end(ap);
 1409 }
 1410 
 1411 void
 1412 vfs_opterror(struct vfsoptlist *opts, const char *fmt, ...)
 1413 {
 1414         va_list ap;
 1415         int error, len;
 1416         char *errmsg;
 1417 
 1418         error = vfs_getopt(opts, "errmsg", (void **)&errmsg, &len);
 1419         if (error || errmsg == NULL || len <= 0)
 1420                 return;
 1421 
 1422         va_start(ap, fmt);
 1423         vsnprintf(errmsg, (size_t)len, fmt, ap);
 1424         va_end(ap);
 1425 }
 1426 
 1427 /*
 1428  * ---------------------------------------------------------------------
 1429  * Functions for querying mount options/arguments from filesystems.
 1430  */
 1431 
 1432 /*
 1433  * Check that no unknown options are given
 1434  */
 1435 int
 1436 vfs_filteropt(struct vfsoptlist *opts, const char **legal)
 1437 {
 1438         struct vfsopt *opt;
 1439         char errmsg[255];
 1440         const char **t, *p, *q;
 1441         int ret = 0;
 1442 
 1443         TAILQ_FOREACH(opt, opts, link) {
 1444                 p = opt->name;
 1445                 q = NULL;
 1446                 if (p[0] == 'n' && p[1] == 'o')
 1447                         q = p + 2;
 1448                 for(t = global_opts; *t != NULL; t++) {
 1449                         if (strcmp(*t, p) == 0)
 1450                                 break;
 1451                         if (q != NULL) {
 1452                                 if (strcmp(*t, q) == 0)
 1453                                         break;
 1454                         }
 1455                 }
 1456                 if (*t != NULL)
 1457                         continue;
 1458                 for(t = legal; *t != NULL; t++) {
 1459                         if (strcmp(*t, p) == 0)
 1460                                 break;
 1461                         if (q != NULL) {
 1462                                 if (strcmp(*t, q) == 0)
 1463                                         break;
 1464                         }
 1465                 }
 1466                 if (*t != NULL)
 1467                         continue;
 1468                 snprintf(errmsg, sizeof(errmsg),
 1469                     "mount option <%s> is unknown", p);
 1470                 ret = EINVAL;
 1471         }
 1472         if (ret != 0) {
 1473                 TAILQ_FOREACH(opt, opts, link) {
 1474                         if (strcmp(opt->name, "errmsg") == 0) {
 1475                                 strncpy((char *)opt->value, errmsg, opt->len);
 1476                                 break;
 1477                         }
 1478                 }
 1479                 if (opt == NULL)
 1480                         printf("%s\n", errmsg);
 1481         }
 1482         return (ret);
 1483 }
 1484 
 1485 /*
 1486  * Get a mount option by its name.
 1487  *
 1488  * Return 0 if the option was found, ENOENT otherwise.
 1489  * If len is non-NULL it will be filled with the length
 1490  * of the option. If buf is non-NULL, it will be filled
 1491  * with the address of the option.
 1492  */
 1493 int
 1494 vfs_getopt(opts, name, buf, len)
 1495         struct vfsoptlist *opts;
 1496         const char *name;
 1497         void **buf;
 1498         int *len;
 1499 {
 1500         struct vfsopt *opt;
 1501 
 1502         KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
 1503 
 1504         TAILQ_FOREACH(opt, opts, link) {
 1505                 if (strcmp(name, opt->name) == 0) {
 1506                         opt->seen = 1;
 1507                         if (len != NULL)
 1508                                 *len = opt->len;
 1509                         if (buf != NULL)
 1510                                 *buf = opt->value;
 1511                         return (0);
 1512                 }
 1513         }
 1514         return (ENOENT);
 1515 }
 1516 
 1517 int
 1518 vfs_getopt_pos(struct vfsoptlist *opts, const char *name)
 1519 {
 1520         struct vfsopt *opt;
 1521 
 1522         if (opts == NULL)
 1523                 return (-1);
 1524 
 1525         TAILQ_FOREACH(opt, opts, link) {
 1526                 if (strcmp(name, opt->name) == 0) {
 1527                         opt->seen = 1;
 1528                         return (opt->pos);
 1529                 }
 1530         }
 1531         return (-1);
 1532 }
 1533 
 1534 int
 1535 vfs_getopt_size(struct vfsoptlist *opts, const char *name, off_t *value)
 1536 {
 1537         char *opt_value, *vtp;
 1538         quad_t iv;
 1539         int error, opt_len;
 1540 
 1541         error = vfs_getopt(opts, name, (void **)&opt_value, &opt_len);
 1542         if (error != 0)
 1543                 return (error);
 1544         if (opt_len == 0 || opt_value == NULL)
 1545                 return (EINVAL);
 1546         if (opt_value[0] == '\0' || opt_value[opt_len - 1] != '\0')
 1547                 return (EINVAL);
 1548         iv = strtoq(opt_value, &vtp, 0);
 1549         if (vtp == opt_value || (vtp[0] != '\0' && vtp[1] != '\0'))
 1550                 return (EINVAL);
 1551         if (iv < 0)
 1552                 return (EINVAL);
 1553         switch (vtp[0]) {
 1554         case 't':
 1555         case 'T':
 1556                 iv *= 1024;
 1557         case 'g':
 1558         case 'G':
 1559                 iv *= 1024;
 1560         case 'm':
 1561         case 'M':
 1562                 iv *= 1024;
 1563         case 'k':
 1564         case 'K':
 1565                 iv *= 1024;
 1566         case '\0':
 1567                 break;
 1568         default:
 1569                 return (EINVAL);
 1570         }
 1571         *value = iv;
 1572 
 1573         return (0);
 1574 }
 1575 
 1576 char *
 1577 vfs_getopts(struct vfsoptlist *opts, const char *name, int *error)
 1578 {
 1579         struct vfsopt *opt;
 1580 
 1581         *error = 0;
 1582         TAILQ_FOREACH(opt, opts, link) {
 1583                 if (strcmp(name, opt->name) != 0)
 1584                         continue;
 1585                 opt->seen = 1;
 1586                 if (opt->len == 0 ||
 1587                     ((char *)opt->value)[opt->len - 1] != '\0') {
 1588                         *error = EINVAL;
 1589                         return (NULL);
 1590                 }
 1591                 return (opt->value);
 1592         }
 1593         *error = ENOENT;
 1594         return (NULL);
 1595 }
 1596 
 1597 int
 1598 vfs_flagopt(struct vfsoptlist *opts, const char *name, uint64_t *w,
 1599         uint64_t val)
 1600 {
 1601         struct vfsopt *opt;
 1602 
 1603         TAILQ_FOREACH(opt, opts, link) {
 1604                 if (strcmp(name, opt->name) == 0) {
 1605                         opt->seen = 1;
 1606                         if (w != NULL)
 1607                                 *w |= val;
 1608                         return (1);
 1609                 }
 1610         }
 1611         if (w != NULL)
 1612                 *w &= ~val;
 1613         return (0);
 1614 }
 1615 
 1616 int
 1617 vfs_scanopt(struct vfsoptlist *opts, const char *name, const char *fmt, ...)
 1618 {
 1619         va_list ap;
 1620         struct vfsopt *opt;
 1621         int ret;
 1622 
 1623         KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
 1624 
 1625         TAILQ_FOREACH(opt, opts, link) {
 1626                 if (strcmp(name, opt->name) != 0)
 1627                         continue;
 1628                 opt->seen = 1;
 1629                 if (opt->len == 0 || opt->value == NULL)
 1630                         return (0);
 1631                 if (((char *)opt->value)[opt->len - 1] != '\0')
 1632                         return (0);
 1633                 va_start(ap, fmt);
 1634                 ret = vsscanf(opt->value, fmt, ap);
 1635                 va_end(ap);
 1636                 return (ret);
 1637         }
 1638         return (0);
 1639 }
 1640 
 1641 int
 1642 vfs_setopt(struct vfsoptlist *opts, const char *name, void *value, int len)
 1643 {
 1644         struct vfsopt *opt;
 1645 
 1646         TAILQ_FOREACH(opt, opts, link) {
 1647                 if (strcmp(name, opt->name) != 0)
 1648                         continue;
 1649                 opt->seen = 1;
 1650                 if (opt->value == NULL)
 1651                         opt->len = len;
 1652                 else {
 1653                         if (opt->len != len)
 1654                                 return (EINVAL);
 1655                         bcopy(value, opt->value, len);
 1656                 }
 1657                 return (0);
 1658         }
 1659         return (ENOENT);
 1660 }
 1661 
 1662 int
 1663 vfs_setopt_part(struct vfsoptlist *opts, const char *name, void *value, int len)
 1664 {
 1665         struct vfsopt *opt;
 1666 
 1667         TAILQ_FOREACH(opt, opts, link) {
 1668                 if (strcmp(name, opt->name) != 0)
 1669                         continue;
 1670                 opt->seen = 1;
 1671                 if (opt->value == NULL)
 1672                         opt->len = len;
 1673                 else {
 1674                         if (opt->len < len)
 1675                                 return (EINVAL);
 1676                         opt->len = len;
 1677                         bcopy(value, opt->value, len);
 1678                 }
 1679                 return (0);
 1680         }
 1681         return (ENOENT);
 1682 }
 1683 
 1684 int
 1685 vfs_setopts(struct vfsoptlist *opts, const char *name, const char *value)
 1686 {
 1687         struct vfsopt *opt;
 1688 
 1689         TAILQ_FOREACH(opt, opts, link) {
 1690                 if (strcmp(name, opt->name) != 0)
 1691                         continue;
 1692                 opt->seen = 1;
 1693                 if (opt->value == NULL)
 1694                         opt->len = strlen(value) + 1;
 1695                 else if (strlcpy(opt->value, value, opt->len) >= opt->len)
 1696                         return (EINVAL);
 1697                 return (0);
 1698         }
 1699         return (ENOENT);
 1700 }
 1701 
 1702 /*
 1703  * Find and copy a mount option.
 1704  *
 1705  * The size of the buffer has to be specified
 1706  * in len, if it is not the same length as the
 1707  * mount option, EINVAL is returned.
 1708  * Returns ENOENT if the option is not found.
 1709  */
 1710 int
 1711 vfs_copyopt(opts, name, dest, len)
 1712         struct vfsoptlist *opts;
 1713         const char *name;
 1714         void *dest;
 1715         int len;
 1716 {
 1717         struct vfsopt *opt;
 1718 
 1719         KASSERT(opts != NULL, ("vfs_copyopt: caller passed 'opts' as NULL"));
 1720 
 1721         TAILQ_FOREACH(opt, opts, link) {
 1722                 if (strcmp(name, opt->name) == 0) {
 1723                         opt->seen = 1;
 1724                         if (len != opt->len)
 1725                                 return (EINVAL);
 1726                         bcopy(opt->value, dest, opt->len);
 1727                         return (0);
 1728                 }
 1729         }
 1730         return (ENOENT);
 1731 }
 1732 
 1733 int
 1734 __vfs_statfs(struct mount *mp, struct statfs *sbp)
 1735 {
 1736         int error;
 1737 
 1738         error = mp->mnt_op->vfs_statfs(mp, &mp->mnt_stat);
 1739         if (sbp != &mp->mnt_stat)
 1740                 *sbp = mp->mnt_stat;
 1741         return (error);
 1742 }
 1743 
 1744 void
 1745 vfs_mountedfrom(struct mount *mp, const char *from)
 1746 {
 1747 
 1748         bzero(mp->mnt_stat.f_mntfromname, sizeof mp->mnt_stat.f_mntfromname);
 1749         strlcpy(mp->mnt_stat.f_mntfromname, from,
 1750             sizeof mp->mnt_stat.f_mntfromname);
 1751 }
 1752 
 1753 /*
 1754  * ---------------------------------------------------------------------
 1755  * This is the api for building mount args and mounting filesystems from
 1756  * inside the kernel.
 1757  *
 1758  * The API works by accumulation of individual args.  First error is
 1759  * latched.
 1760  *
 1761  * XXX: should be documented in new manpage kernel_mount(9)
 1762  */
 1763 
 1764 /* A memory allocation which must be freed when we are done */
 1765 struct mntaarg {
 1766         SLIST_ENTRY(mntaarg)    next;
 1767 };
 1768 
 1769 /* The header for the mount arguments */
 1770 struct mntarg {
 1771         struct iovec *v;
 1772         int len;
 1773         int error;
 1774         SLIST_HEAD(, mntaarg)   list;
 1775 };
 1776 
 1777 /*
 1778  * Add a boolean argument.
 1779  *
 1780  * flag is the boolean value.
 1781  * name must start with "no".
 1782  */
 1783 struct mntarg *
 1784 mount_argb(struct mntarg *ma, int flag, const char *name)
 1785 {
 1786 
 1787         KASSERT(name[0] == 'n' && name[1] == 'o',
 1788             ("mount_argb(...,%s): name must start with 'no'", name));
 1789 
 1790         return (mount_arg(ma, name + (flag ? 2 : 0), NULL, 0));
 1791 }
 1792 
 1793 /*
 1794  * Add an argument printf style
 1795  */
 1796 struct mntarg *
 1797 mount_argf(struct mntarg *ma, const char *name, const char *fmt, ...)
 1798 {
 1799         va_list ap;
 1800         struct mntaarg *maa;
 1801         struct sbuf *sb;
 1802         int len;
 1803 
 1804         if (ma == NULL) {
 1805                 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
 1806                 SLIST_INIT(&ma->list);
 1807         }
 1808         if (ma->error)
 1809                 return (ma);
 1810 
 1811         ma->v = realloc(ma->v, sizeof *ma->v * (ma->len + 2),
 1812             M_MOUNT, M_WAITOK);
 1813         ma->v[ma->len].iov_base = (void *)(uintptr_t)name;
 1814         ma->v[ma->len].iov_len = strlen(name) + 1;
 1815         ma->len++;
 1816 
 1817         sb = sbuf_new_auto();
 1818         va_start(ap, fmt);
 1819         sbuf_vprintf(sb, fmt, ap);
 1820         va_end(ap);
 1821         sbuf_finish(sb);
 1822         len = sbuf_len(sb) + 1;
 1823         maa = malloc(sizeof *maa + len, M_MOUNT, M_WAITOK | M_ZERO);
 1824         SLIST_INSERT_HEAD(&ma->list, maa, next);
 1825         bcopy(sbuf_data(sb), maa + 1, len);
 1826         sbuf_delete(sb);
 1827 
 1828         ma->v[ma->len].iov_base = maa + 1;
 1829         ma->v[ma->len].iov_len = len;
 1830         ma->len++;
 1831 
 1832         return (ma);
 1833 }
 1834 
 1835 /*
 1836  * Add an argument which is a userland string.
 1837  */
 1838 struct mntarg *
 1839 mount_argsu(struct mntarg *ma, const char *name, const void *val, int len)
 1840 {
 1841         struct mntaarg *maa;
 1842         char *tbuf;
 1843 
 1844         if (val == NULL)
 1845                 return (ma);
 1846         if (ma == NULL) {
 1847                 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
 1848                 SLIST_INIT(&ma->list);
 1849         }
 1850         if (ma->error)
 1851                 return (ma);
 1852         maa = malloc(sizeof *maa + len, M_MOUNT, M_WAITOK | M_ZERO);
 1853         SLIST_INSERT_HEAD(&ma->list, maa, next);
 1854         tbuf = (void *)(maa + 1);
 1855         ma->error = copyinstr(val, tbuf, len, NULL);
 1856         return (mount_arg(ma, name, tbuf, -1));
 1857 }
 1858 
 1859 /*
 1860  * Plain argument.
 1861  *
 1862  * If length is -1, treat value as a C string.
 1863  */
 1864 struct mntarg *
 1865 mount_arg(struct mntarg *ma, const char *name, const void *val, int len)
 1866 {
 1867 
 1868         if (ma == NULL) {
 1869                 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
 1870                 SLIST_INIT(&ma->list);
 1871         }
 1872         if (ma->error)
 1873                 return (ma);
 1874 
 1875         ma->v = realloc(ma->v, sizeof *ma->v * (ma->len + 2),
 1876             M_MOUNT, M_WAITOK);
 1877         ma->v[ma->len].iov_base = (void *)(uintptr_t)name;
 1878         ma->v[ma->len].iov_len = strlen(name) + 1;
 1879         ma->len++;
 1880 
 1881         ma->v[ma->len].iov_base = (void *)(uintptr_t)val;
 1882         if (len < 0)
 1883                 ma->v[ma->len].iov_len = strlen(val) + 1;
 1884         else
 1885                 ma->v[ma->len].iov_len = len;
 1886         ma->len++;
 1887         return (ma);
 1888 }
 1889 
 1890 /*
 1891  * Free a mntarg structure
 1892  */
 1893 static void
 1894 free_mntarg(struct mntarg *ma)
 1895 {
 1896         struct mntaarg *maa;
 1897 
 1898         while (!SLIST_EMPTY(&ma->list)) {
 1899                 maa = SLIST_FIRST(&ma->list);
 1900                 SLIST_REMOVE_HEAD(&ma->list, next);
 1901                 free(maa, M_MOUNT);
 1902         }
 1903         free(ma->v, M_MOUNT);
 1904         free(ma, M_MOUNT);
 1905 }
 1906 
 1907 /*
 1908  * Mount a filesystem
 1909  */
 1910 int
 1911 kernel_mount(struct mntarg *ma, uint64_t flags)
 1912 {
 1913         struct uio auio;
 1914         int error;
 1915 
 1916         KASSERT(ma != NULL, ("kernel_mount NULL ma"));
 1917         KASSERT(ma->v != NULL, ("kernel_mount NULL ma->v"));
 1918         KASSERT(!(ma->len & 1), ("kernel_mount odd ma->len (%d)", ma->len));
 1919 
 1920         auio.uio_iov = ma->v;
 1921         auio.uio_iovcnt = ma->len;
 1922         auio.uio_segflg = UIO_SYSSPACE;
 1923 
 1924         error = ma->error;
 1925         if (!error)
 1926                 error = vfs_donmount(curthread, flags, &auio);
 1927         free_mntarg(ma);
 1928         return (error);
 1929 }
 1930 
 1931 /*
 1932  * A printflike function to mount a filesystem.
 1933  */
 1934 int
 1935 kernel_vmount(int flags, ...)
 1936 {
 1937         struct mntarg *ma = NULL;
 1938         va_list ap;
 1939         const char *cp;
 1940         const void *vp;
 1941         int error;
 1942 
 1943         va_start(ap, flags);
 1944         for (;;) {
 1945                 cp = va_arg(ap, const char *);
 1946                 if (cp == NULL)
 1947                         break;
 1948                 vp = va_arg(ap, const void *);
 1949                 ma = mount_arg(ma, cp, vp, (vp != NULL ? -1 : 0));
 1950         }
 1951         va_end(ap);
 1952 
 1953         error = kernel_mount(ma, flags);
 1954         return (error);
 1955 }
 1956 
 1957 void
 1958 vfs_oexport_conv(const struct oexport_args *oexp, struct export_args *exp)
 1959 {
 1960 
 1961         bcopy(oexp, exp, sizeof(*oexp));
 1962         exp->ex_numsecflavors = 0;
 1963 }

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