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/9.0/sys/kern/vfs_mount.c 226622 2011-10-21 22:12:24Z mckusick $");
   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,
   74                     char *fspath, int 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 MALLOC_DEFINE(M_VNODE_MARKER, "vnodemarker", "vnode marker");
   83 static uma_zone_t mount_zone;
   84 
   85 /* List of mounted filesystems. */
   86 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist);
   87 
   88 /* For any iteration/modification of mountlist */
   89 struct mtx mountlist_mtx;
   90 MTX_SYSINIT(mountlist, &mountlist_mtx, "mountlist", MTX_DEF);
   91 
   92 /*
   93  * Global opts, taken by all filesystems
   94  */
   95 static const char *global_opts[] = {
   96         "errmsg",
   97         "fstype",
   98         "fspath",
   99         "ro",
  100         "rw",
  101         "nosuid",
  102         "noexec",
  103         NULL
  104 };
  105 
  106 static int
  107 mount_init(void *mem, int size, int flags)
  108 {
  109         struct mount *mp;
  110 
  111         mp = (struct mount *)mem;
  112         mtx_init(&mp->mnt_mtx, "struct mount mtx", NULL, MTX_DEF);
  113         lockinit(&mp->mnt_explock, PVFS, "explock", 0, 0);
  114         return (0);
  115 }
  116 
  117 static void
  118 mount_fini(void *mem, int size)
  119 {
  120         struct mount *mp;
  121 
  122         mp = (struct mount *)mem;
  123         lockdestroy(&mp->mnt_explock);
  124         mtx_destroy(&mp->mnt_mtx);
  125 }
  126 
  127 static void
  128 vfs_mount_init(void *dummy __unused)
  129 {
  130 
  131         mount_zone = uma_zcreate("Mountpoints", sizeof(struct mount), NULL,
  132             NULL, mount_init, mount_fini, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  133 }
  134 SYSINIT(vfs_mount, SI_SUB_VFS, SI_ORDER_ANY, vfs_mount_init, NULL);
  135 
  136 /*
  137  * ---------------------------------------------------------------------
  138  * Functions for building and sanitizing the mount options
  139  */
  140 
  141 /* Remove one mount option. */
  142 static void
  143 vfs_freeopt(struct vfsoptlist *opts, struct vfsopt *opt)
  144 {
  145 
  146         TAILQ_REMOVE(opts, opt, link);
  147         free(opt->name, M_MOUNT);
  148         if (opt->value != NULL)
  149                 free(opt->value, M_MOUNT);
  150         free(opt, M_MOUNT);
  151 }
  152 
  153 /* Release all resources related to the mount options. */
  154 void
  155 vfs_freeopts(struct vfsoptlist *opts)
  156 {
  157         struct vfsopt *opt;
  158 
  159         while (!TAILQ_EMPTY(opts)) {
  160                 opt = TAILQ_FIRST(opts);
  161                 vfs_freeopt(opts, opt);
  162         }
  163         free(opts, M_MOUNT);
  164 }
  165 
  166 void
  167 vfs_deleteopt(struct vfsoptlist *opts, const char *name)
  168 {
  169         struct vfsopt *opt, *temp;
  170 
  171         if (opts == NULL)
  172                 return;
  173         TAILQ_FOREACH_SAFE(opt, opts, link, temp)  {
  174                 if (strcmp(opt->name, name) == 0)
  175                         vfs_freeopt(opts, opt);
  176         }
  177 }
  178 
  179 static int
  180 vfs_isopt_ro(const char *opt)
  181 {
  182 
  183         if (strcmp(opt, "ro") == 0 || strcmp(opt, "rdonly") == 0 ||
  184             strcmp(opt, "norw") == 0)
  185                 return (1);
  186         return (0);
  187 }
  188 
  189 static int
  190 vfs_isopt_rw(const char *opt)
  191 {
  192 
  193         if (strcmp(opt, "rw") == 0 || strcmp(opt, "noro") == 0)
  194                 return (1);
  195         return (0);
  196 }
  197 
  198 /*
  199  * Check if options are equal (with or without the "no" prefix).
  200  */
  201 static int
  202 vfs_equalopts(const char *opt1, const char *opt2)
  203 {
  204         char *p;
  205 
  206         /* "opt" vs. "opt" or "noopt" vs. "noopt" */
  207         if (strcmp(opt1, opt2) == 0)
  208                 return (1);
  209         /* "noopt" vs. "opt" */
  210         if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
  211                 return (1);
  212         /* "opt" vs. "noopt" */
  213         if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
  214                 return (1);
  215         while ((p = strchr(opt1, '.')) != NULL &&
  216             !strncmp(opt1, opt2, ++p - opt1)) {
  217                 opt2 += p - opt1;
  218                 opt1 = p;
  219                 /* "foo.noopt" vs. "foo.opt" */
  220                 if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
  221                         return (1);
  222                 /* "foo.opt" vs. "foo.noopt" */
  223                 if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
  224                         return (1);
  225         }
  226         /* "ro" / "rdonly" / "norw" / "rw" / "noro" */
  227         if ((vfs_isopt_ro(opt1) || vfs_isopt_rw(opt1)) &&
  228             (vfs_isopt_ro(opt2) || vfs_isopt_rw(opt2)))
  229                 return (1);
  230         return (0);
  231 }
  232 
  233 /*
  234  * If a mount option is specified several times,
  235  * (with or without the "no" prefix) only keep
  236  * the last occurence of it.
  237  */
  238 static void
  239 vfs_sanitizeopts(struct vfsoptlist *opts)
  240 {
  241         struct vfsopt *opt, *opt2, *tmp;
  242 
  243         TAILQ_FOREACH_REVERSE(opt, opts, vfsoptlist, link) {
  244                 opt2 = TAILQ_PREV(opt, vfsoptlist, link);
  245                 while (opt2 != NULL) {
  246                         if (vfs_equalopts(opt->name, opt2->name)) {
  247                                 tmp = TAILQ_PREV(opt2, vfsoptlist, link);
  248                                 vfs_freeopt(opts, opt2);
  249                                 opt2 = tmp;
  250                         } else {
  251                                 opt2 = TAILQ_PREV(opt2, vfsoptlist, link);
  252                         }
  253                 }
  254         }
  255 }
  256 
  257 /*
  258  * Build a linked list of mount options from a struct uio.
  259  */
  260 int
  261 vfs_buildopts(struct uio *auio, struct vfsoptlist **options)
  262 {
  263         struct vfsoptlist *opts;
  264         struct vfsopt *opt;
  265         size_t memused, namelen, optlen;
  266         unsigned int i, iovcnt;
  267         int error;
  268 
  269         opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
  270         TAILQ_INIT(opts);
  271         memused = 0;
  272         iovcnt = auio->uio_iovcnt;
  273         for (i = 0; i < iovcnt; i += 2) {
  274                 namelen = auio->uio_iov[i].iov_len;
  275                 optlen = auio->uio_iov[i + 1].iov_len;
  276                 memused += sizeof(struct vfsopt) + optlen + namelen;
  277                 /*
  278                  * Avoid consuming too much memory, and attempts to overflow
  279                  * memused.
  280                  */
  281                 if (memused > VFS_MOUNTARG_SIZE_MAX ||
  282                     optlen > VFS_MOUNTARG_SIZE_MAX ||
  283                     namelen > VFS_MOUNTARG_SIZE_MAX) {
  284                         error = EINVAL;
  285                         goto bad;
  286                 }
  287 
  288                 opt = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
  289                 opt->name = malloc(namelen, M_MOUNT, M_WAITOK);
  290                 opt->value = NULL;
  291                 opt->len = 0;
  292                 opt->pos = i / 2;
  293                 opt->seen = 0;
  294 
  295                 /*
  296                  * Do this early, so jumps to "bad" will free the current
  297                  * option.
  298                  */
  299                 TAILQ_INSERT_TAIL(opts, opt, link);
  300 
  301                 if (auio->uio_segflg == UIO_SYSSPACE) {
  302                         bcopy(auio->uio_iov[i].iov_base, opt->name, namelen);
  303                 } else {
  304                         error = copyin(auio->uio_iov[i].iov_base, opt->name,
  305                             namelen);
  306                         if (error)
  307                                 goto bad;
  308                 }
  309                 /* Ensure names are null-terminated strings. */
  310                 if (namelen == 0 || opt->name[namelen - 1] != '\0') {
  311                         error = EINVAL;
  312                         goto bad;
  313                 }
  314                 if (optlen != 0) {
  315                         opt->len = optlen;
  316                         opt->value = malloc(optlen, M_MOUNT, M_WAITOK);
  317                         if (auio->uio_segflg == UIO_SYSSPACE) {
  318                                 bcopy(auio->uio_iov[i + 1].iov_base, opt->value,
  319                                     optlen);
  320                         } else {
  321                                 error = copyin(auio->uio_iov[i + 1].iov_base,
  322                                     opt->value, optlen);
  323                                 if (error)
  324                                         goto bad;
  325                         }
  326                 }
  327         }
  328         vfs_sanitizeopts(opts);
  329         *options = opts;
  330         return (0);
  331 bad:
  332         vfs_freeopts(opts);
  333         return (error);
  334 }
  335 
  336 /*
  337  * Merge the old mount options with the new ones passed
  338  * in the MNT_UPDATE case.
  339  *
  340  * XXX: This function will keep a "nofoo" option in the new
  341  * options.  E.g, if the option's canonical name is "foo",
  342  * "nofoo" ends up in the mount point's active options.
  343  */
  344 static void
  345 vfs_mergeopts(struct vfsoptlist *toopts, struct vfsoptlist *oldopts)
  346 {
  347         struct vfsopt *opt, *new;
  348 
  349         TAILQ_FOREACH(opt, oldopts, link) {
  350                 new = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
  351                 new->name = strdup(opt->name, M_MOUNT);
  352                 if (opt->len != 0) {
  353                         new->value = malloc(opt->len, M_MOUNT, M_WAITOK);
  354                         bcopy(opt->value, new->value, opt->len);
  355                 } else
  356                         new->value = NULL;
  357                 new->len = opt->len;
  358                 new->seen = opt->seen;
  359                 TAILQ_INSERT_HEAD(toopts, new, link);
  360         }
  361         vfs_sanitizeopts(toopts);
  362 }
  363 
  364 /*
  365  * Mount a filesystem.
  366  */
  367 int
  368 sys_nmount(td, uap)
  369         struct thread *td;
  370         struct nmount_args /* {
  371                 struct iovec *iovp;
  372                 unsigned int iovcnt;
  373                 int flags;
  374         } */ *uap;
  375 {
  376         struct uio *auio;
  377         int error;
  378         u_int iovcnt;
  379 
  380         AUDIT_ARG_FFLAGS(uap->flags);
  381         CTR4(KTR_VFS, "%s: iovp %p with iovcnt %d and flags %d", __func__,
  382             uap->iovp, uap->iovcnt, uap->flags);
  383 
  384         /*
  385          * Filter out MNT_ROOTFS.  We do not want clients of nmount() in
  386          * userspace to set this flag, but we must filter it out if we want
  387          * MNT_UPDATE on the root file system to work.
  388          * MNT_ROOTFS should only be set by the kernel when mounting its
  389          * root file system.
  390          */
  391         uap->flags &= ~MNT_ROOTFS;
  392 
  393         iovcnt = uap->iovcnt;
  394         /*
  395          * Check that we have an even number of iovec's
  396          * and that we have at least two options.
  397          */
  398         if ((iovcnt & 1) || (iovcnt < 4)) {
  399                 CTR2(KTR_VFS, "%s: failed for invalid iovcnt %d", __func__,
  400                     uap->iovcnt);
  401                 return (EINVAL);
  402         }
  403 
  404         error = copyinuio(uap->iovp, iovcnt, &auio);
  405         if (error) {
  406                 CTR2(KTR_VFS, "%s: failed for invalid uio op with %d errno",
  407                     __func__, error);
  408                 return (error);
  409         }
  410         error = vfs_donmount(td, uap->flags, auio);
  411 
  412         free(auio, M_IOV);
  413         return (error);
  414 }
  415 
  416 /*
  417  * ---------------------------------------------------------------------
  418  * Various utility functions
  419  */
  420 
  421 void
  422 vfs_ref(struct mount *mp)
  423 {
  424 
  425         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  426         MNT_ILOCK(mp);
  427         MNT_REF(mp);
  428         MNT_IUNLOCK(mp);
  429 }
  430 
  431 void
  432 vfs_rel(struct mount *mp)
  433 {
  434 
  435         CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
  436         MNT_ILOCK(mp);
  437         MNT_REL(mp);
  438         MNT_IUNLOCK(mp);
  439 }
  440 
  441 /*
  442  * Allocate and initialize the mount point struct.
  443  */
  444 struct mount *
  445 vfs_mount_alloc(struct vnode *vp, struct vfsconf *vfsp, const char *fspath,
  446     struct ucred *cred)
  447 {
  448         struct mount *mp;
  449 
  450         mp = uma_zalloc(mount_zone, M_WAITOK);
  451         bzero(&mp->mnt_startzero,
  452             __rangeof(struct mount, mnt_startzero, mnt_endzero));
  453         TAILQ_INIT(&mp->mnt_nvnodelist);
  454         mp->mnt_nvnodelistsize = 0;
  455         mp->mnt_ref = 0;
  456         (void) vfs_busy(mp, MBF_NOWAIT);
  457         mp->mnt_op = vfsp->vfc_vfsops;
  458         mp->mnt_vfc = vfsp;
  459         vfsp->vfc_refcount++;   /* XXX Unlocked */
  460         mp->mnt_stat.f_type = vfsp->vfc_typenum;
  461         mp->mnt_gen++;
  462         strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
  463         mp->mnt_vnodecovered = vp;
  464         mp->mnt_cred = crdup(cred);
  465         mp->mnt_stat.f_owner = cred->cr_uid;
  466         strlcpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
  467         mp->mnt_iosize_max = DFLTPHYS;
  468 #ifdef MAC
  469         mac_mount_init(mp);
  470         mac_mount_create(cred, mp);
  471 #endif
  472         arc4rand(&mp->mnt_hashseed, sizeof mp->mnt_hashseed, 0);
  473         return (mp);
  474 }
  475 
  476 /*
  477  * Destroy the mount struct previously allocated by vfs_mount_alloc().
  478  */
  479 void
  480 vfs_mount_destroy(struct mount *mp)
  481 {
  482 
  483         MNT_ILOCK(mp);
  484         mp->mnt_kern_flag |= MNTK_REFEXPIRE;
  485         if (mp->mnt_kern_flag & MNTK_MWAIT) {
  486                 mp->mnt_kern_flag &= ~MNTK_MWAIT;
  487                 wakeup(mp);
  488         }
  489         while (mp->mnt_ref)
  490                 msleep(mp, MNT_MTX(mp), PVFS, "mntref", 0);
  491         KASSERT(mp->mnt_ref == 0,
  492             ("%s: invalid refcount in the drain path @ %s:%d", __func__,
  493             __FILE__, __LINE__));
  494         if (mp->mnt_writeopcount != 0)
  495                 panic("vfs_mount_destroy: nonzero writeopcount");
  496         if (mp->mnt_secondary_writes != 0)
  497                 panic("vfs_mount_destroy: nonzero secondary_writes");
  498         mp->mnt_vfc->vfc_refcount--;
  499         if (!TAILQ_EMPTY(&mp->mnt_nvnodelist)) {
  500                 struct vnode *vp;
  501 
  502                 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes)
  503                         vprint("", vp);
  504                 panic("unmount: dangling vnode");
  505         }
  506         if (mp->mnt_nvnodelistsize != 0)
  507                 panic("vfs_mount_destroy: nonzero nvnodelistsize");
  508         if (mp->mnt_lockref != 0)
  509                 panic("vfs_mount_destroy: nonzero lock refcount");
  510         MNT_IUNLOCK(mp);
  511 #ifdef MAC
  512         mac_mount_destroy(mp);
  513 #endif
  514         if (mp->mnt_opt != NULL)
  515                 vfs_freeopts(mp->mnt_opt);
  516         crfree(mp->mnt_cred);
  517         uma_zfree(mount_zone, mp);
  518 }
  519 
  520 int
  521 vfs_donmount(struct thread *td, int fsflags, struct uio *fsoptions)
  522 {
  523         struct vfsoptlist *optlist;
  524         struct vfsopt *opt, *tmp_opt;
  525         char *fstype, *fspath, *errmsg;
  526         int error, fstypelen, fspathlen, errmsg_len, errmsg_pos;
  527 
  528         errmsg = fspath = NULL;
  529         errmsg_len = fspathlen = 0;
  530         errmsg_pos = -1;
  531 
  532         error = vfs_buildopts(fsoptions, &optlist);
  533         if (error)
  534                 return (error);
  535 
  536         if (vfs_getopt(optlist, "errmsg", (void **)&errmsg, &errmsg_len) == 0)
  537                 errmsg_pos = vfs_getopt_pos(optlist, "errmsg");
  538 
  539         /*
  540          * We need these two options before the others,
  541          * and they are mandatory for any filesystem.
  542          * Ensure they are NUL terminated as well.
  543          */
  544         fstypelen = 0;
  545         error = vfs_getopt(optlist, "fstype", (void **)&fstype, &fstypelen);
  546         if (error || fstype[fstypelen - 1] != '\0') {
  547                 error = EINVAL;
  548                 if (errmsg != NULL)
  549                         strncpy(errmsg, "Invalid fstype", errmsg_len);
  550                 goto bail;
  551         }
  552         fspathlen = 0;
  553         error = vfs_getopt(optlist, "fspath", (void **)&fspath, &fspathlen);
  554         if (error || fspath[fspathlen - 1] != '\0') {
  555                 error = EINVAL;
  556                 if (errmsg != NULL)
  557                         strncpy(errmsg, "Invalid fspath", errmsg_len);
  558                 goto bail;
  559         }
  560 
  561         /*
  562          * We need to see if we have the "update" option
  563          * before we call vfs_domount(), since vfs_domount() has special
  564          * logic based on MNT_UPDATE.  This is very important
  565          * when we want to update the root filesystem.
  566          */
  567         TAILQ_FOREACH_SAFE(opt, optlist, link, tmp_opt) {
  568                 if (strcmp(opt->name, "update") == 0) {
  569                         fsflags |= MNT_UPDATE;
  570                         vfs_freeopt(optlist, opt);
  571                 }
  572                 else if (strcmp(opt->name, "async") == 0)
  573                         fsflags |= MNT_ASYNC;
  574                 else if (strcmp(opt->name, "force") == 0) {
  575                         fsflags |= MNT_FORCE;
  576                         vfs_freeopt(optlist, opt);
  577                 }
  578                 else if (strcmp(opt->name, "reload") == 0) {
  579                         fsflags |= MNT_RELOAD;
  580                         vfs_freeopt(optlist, opt);
  581                 }
  582                 else if (strcmp(opt->name, "multilabel") == 0)
  583                         fsflags |= MNT_MULTILABEL;
  584                 else if (strcmp(opt->name, "noasync") == 0)
  585                         fsflags &= ~MNT_ASYNC;
  586                 else if (strcmp(opt->name, "noatime") == 0)
  587                         fsflags |= MNT_NOATIME;
  588                 else if (strcmp(opt->name, "atime") == 0) {
  589                         free(opt->name, M_MOUNT);
  590                         opt->name = strdup("nonoatime", M_MOUNT);
  591                 }
  592                 else if (strcmp(opt->name, "noclusterr") == 0)
  593                         fsflags |= MNT_NOCLUSTERR;
  594                 else if (strcmp(opt->name, "clusterr") == 0) {
  595                         free(opt->name, M_MOUNT);
  596                         opt->name = strdup("nonoclusterr", M_MOUNT);
  597                 }
  598                 else if (strcmp(opt->name, "noclusterw") == 0)
  599                         fsflags |= MNT_NOCLUSTERW;
  600                 else if (strcmp(opt->name, "clusterw") == 0) {
  601                         free(opt->name, M_MOUNT);
  602                         opt->name = strdup("nonoclusterw", M_MOUNT);
  603                 }
  604                 else if (strcmp(opt->name, "noexec") == 0)
  605                         fsflags |= MNT_NOEXEC;
  606                 else if (strcmp(opt->name, "exec") == 0) {
  607                         free(opt->name, M_MOUNT);
  608                         opt->name = strdup("nonoexec", M_MOUNT);
  609                 }
  610                 else if (strcmp(opt->name, "nosuid") == 0)
  611                         fsflags |= MNT_NOSUID;
  612                 else if (strcmp(opt->name, "suid") == 0) {
  613                         free(opt->name, M_MOUNT);
  614                         opt->name = strdup("nonosuid", M_MOUNT);
  615                 }
  616                 else if (strcmp(opt->name, "nosymfollow") == 0)
  617                         fsflags |= MNT_NOSYMFOLLOW;
  618                 else if (strcmp(opt->name, "symfollow") == 0) {
  619                         free(opt->name, M_MOUNT);
  620                         opt->name = strdup("nonosymfollow", M_MOUNT);
  621                 }
  622                 else if (strcmp(opt->name, "noro") == 0)
  623                         fsflags &= ~MNT_RDONLY;
  624                 else if (strcmp(opt->name, "rw") == 0)
  625                         fsflags &= ~MNT_RDONLY;
  626                 else if (strcmp(opt->name, "ro") == 0)
  627                         fsflags |= MNT_RDONLY;
  628                 else if (strcmp(opt->name, "rdonly") == 0) {
  629                         free(opt->name, M_MOUNT);
  630                         opt->name = strdup("ro", M_MOUNT);
  631                         fsflags |= MNT_RDONLY;
  632                 }
  633                 else if (strcmp(opt->name, "suiddir") == 0)
  634                         fsflags |= MNT_SUIDDIR;
  635                 else if (strcmp(opt->name, "sync") == 0)
  636                         fsflags |= MNT_SYNCHRONOUS;
  637                 else if (strcmp(opt->name, "union") == 0)
  638                         fsflags |= MNT_UNION;
  639         }
  640 
  641         /*
  642          * Be ultra-paranoid about making sure the type and fspath
  643          * variables will fit in our mp buffers, including the
  644          * terminating NUL.
  645          */
  646         if (fstypelen >= MFSNAMELEN - 1 || fspathlen >= MNAMELEN - 1) {
  647                 error = ENAMETOOLONG;
  648                 goto bail;
  649         }
  650 
  651         error = vfs_domount(td, fstype, fspath, fsflags, &optlist);
  652 bail:
  653         /* copyout the errmsg */
  654         if (errmsg_pos != -1 && ((2 * errmsg_pos + 1) < fsoptions->uio_iovcnt)
  655             && errmsg_len > 0 && errmsg != NULL) {
  656                 if (fsoptions->uio_segflg == UIO_SYSSPACE) {
  657                         bcopy(errmsg,
  658                             fsoptions->uio_iov[2 * errmsg_pos + 1].iov_base,
  659                             fsoptions->uio_iov[2 * errmsg_pos + 1].iov_len);
  660                 } else {
  661                         copyout(errmsg,
  662                             fsoptions->uio_iov[2 * errmsg_pos + 1].iov_base,
  663                             fsoptions->uio_iov[2 * errmsg_pos + 1].iov_len);
  664                 }
  665         }
  666 
  667         if (optlist != NULL)
  668                 vfs_freeopts(optlist);
  669         return (error);
  670 }
  671 
  672 /*
  673  * Old mount API.
  674  */
  675 #ifndef _SYS_SYSPROTO_H_
  676 struct mount_args {
  677         char    *type;
  678         char    *path;
  679         int     flags;
  680         caddr_t data;
  681 };
  682 #endif
  683 /* ARGSUSED */
  684 int
  685 sys_mount(td, uap)
  686         struct thread *td;
  687         struct mount_args /* {
  688                 char *type;
  689                 char *path;
  690                 int flags;
  691                 caddr_t data;
  692         } */ *uap;
  693 {
  694         char *fstype;
  695         struct vfsconf *vfsp = NULL;
  696         struct mntarg *ma = NULL;
  697         int error;
  698 
  699         AUDIT_ARG_FFLAGS(uap->flags);
  700 
  701         /*
  702          * Filter out MNT_ROOTFS.  We do not want clients of mount() in
  703          * userspace to set this flag, but we must filter it out if we want
  704          * MNT_UPDATE on the root file system to work.
  705          * MNT_ROOTFS should only be set by the kernel when mounting its
  706          * root file system.
  707          */
  708         uap->flags &= ~MNT_ROOTFS;
  709 
  710         fstype = malloc(MFSNAMELEN, M_TEMP, M_WAITOK);
  711         error = copyinstr(uap->type, fstype, MFSNAMELEN, NULL);
  712         if (error) {
  713                 free(fstype, M_TEMP);
  714                 return (error);
  715         }
  716 
  717         AUDIT_ARG_TEXT(fstype);
  718         mtx_lock(&Giant);
  719         vfsp = vfs_byname_kld(fstype, td, &error);
  720         free(fstype, M_TEMP);
  721         if (vfsp == NULL) {
  722                 mtx_unlock(&Giant);
  723                 return (ENOENT);
  724         }
  725         if (vfsp->vfc_vfsops->vfs_cmount == NULL) {
  726                 mtx_unlock(&Giant);
  727                 return (EOPNOTSUPP);
  728         }
  729 
  730         ma = mount_argsu(ma, "fstype", uap->type, MNAMELEN);
  731         ma = mount_argsu(ma, "fspath", uap->path, MNAMELEN);
  732         ma = mount_argb(ma, uap->flags & MNT_RDONLY, "noro");
  733         ma = mount_argb(ma, !(uap->flags & MNT_NOSUID), "nosuid");
  734         ma = mount_argb(ma, !(uap->flags & MNT_NOEXEC), "noexec");
  735 
  736         error = vfsp->vfc_vfsops->vfs_cmount(ma, uap->data, uap->flags);
  737         mtx_unlock(&Giant);
  738         return (error);
  739 }
  740 
  741 /*
  742  * vfs_domount_first(): first file system mount (not update)
  743  */
  744 static int
  745 vfs_domount_first(
  746         struct thread *td,              /* Calling thread. */
  747         struct vfsconf *vfsp,           /* File system type. */
  748         char *fspath,                   /* Mount path. */
  749         struct vnode *vp,               /* Vnode to be covered. */
  750         int fsflags,                    /* Flags common to all filesystems. */
  751         struct vfsoptlist **optlist     /* Options local to the filesystem. */
  752         )
  753 {
  754         struct vattr va;
  755         struct mount *mp;
  756         struct vnode *newdp;
  757         int error;
  758 
  759         mtx_assert(&Giant, MA_OWNED);
  760         ASSERT_VOP_ELOCKED(vp, __func__);
  761         KASSERT((fsflags & MNT_UPDATE) == 0, ("MNT_UPDATE shouldn't be here"));
  762 
  763         /*
  764          * If the user is not root, ensure that they own the directory
  765          * onto which we are attempting to mount.
  766          */
  767         error = VOP_GETATTR(vp, &va, td->td_ucred);
  768         if (error == 0 && va.va_uid != td->td_ucred->cr_uid)
  769                 error = priv_check_cred(td->td_ucred, PRIV_VFS_ADMIN, 0);
  770         if (error == 0)
  771                 error = vinvalbuf(vp, V_SAVE, 0, 0);
  772         if (error == 0 && vp->v_type != VDIR)
  773                 error = ENOTDIR;
  774         if (error == 0) {
  775                 VI_LOCK(vp);
  776                 if ((vp->v_iflag & VI_MOUNT) == 0 && vp->v_mountedhere == NULL)
  777                         vp->v_iflag |= VI_MOUNT;
  778                 else
  779                         error = EBUSY;
  780                 VI_UNLOCK(vp);
  781         }
  782         if (error != 0) {
  783                 vput(vp);
  784                 return (error);
  785         }
  786         VOP_UNLOCK(vp, 0);
  787 
  788         /* Allocate and initialize the filesystem. */
  789         mp = vfs_mount_alloc(vp, vfsp, fspath, td->td_ucred);
  790         /* XXXMAC: pass to vfs_mount_alloc? */
  791         mp->mnt_optnew = *optlist;
  792         /* Set the mount level flags. */
  793         mp->mnt_flag = (fsflags & (MNT_UPDATEMASK | MNT_ROOTFS | MNT_RDONLY));
  794 
  795         /*
  796          * Mount the filesystem.
  797          * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
  798          * get.  No freeing of cn_pnbuf.
  799          */
  800         error = VFS_MOUNT(mp);
  801         if (error != 0) {
  802                 vfs_unbusy(mp);
  803                 vfs_mount_destroy(mp);
  804                 VI_LOCK(vp);
  805                 vp->v_iflag &= ~VI_MOUNT;
  806                 VI_UNLOCK(vp);
  807                 vrele(vp);
  808                 return (error);
  809         }
  810 
  811         if (mp->mnt_opt != NULL)
  812                 vfs_freeopts(mp->mnt_opt);
  813         mp->mnt_opt = mp->mnt_optnew;
  814         *optlist = NULL;
  815         (void)VFS_STATFS(mp, &mp->mnt_stat);
  816 
  817         /*
  818          * Prevent external consumers of mount options from reading mnt_optnew.
  819          */
  820         mp->mnt_optnew = NULL;
  821 
  822         MNT_ILOCK(mp);
  823         if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
  824                 mp->mnt_kern_flag |= MNTK_ASYNC;
  825         else
  826                 mp->mnt_kern_flag &= ~MNTK_ASYNC;
  827         MNT_IUNLOCK(mp);
  828 
  829         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
  830         cache_purge(vp);
  831         VI_LOCK(vp);
  832         vp->v_iflag &= ~VI_MOUNT;
  833         VI_UNLOCK(vp);
  834         vp->v_mountedhere = mp;
  835         /* Place the new filesystem at the end of the mount list. */
  836         mtx_lock(&mountlist_mtx);
  837         TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
  838         mtx_unlock(&mountlist_mtx);
  839         vfs_event_signal(NULL, VQ_MOUNT, 0);
  840         if (VFS_ROOT(mp, LK_EXCLUSIVE, &newdp))
  841                 panic("mount: lost mount");
  842         VOP_UNLOCK(newdp, 0);
  843         VOP_UNLOCK(vp, 0);
  844         mountcheckdirs(vp, newdp);
  845         vrele(newdp);
  846         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  847                 vfs_allocate_syncvnode(mp);
  848         vfs_unbusy(mp);
  849         return (0);
  850 }
  851 
  852 /*
  853  * vfs_domount_update(): update of mounted file system
  854  */
  855 static int
  856 vfs_domount_update(
  857         struct thread *td,              /* Calling thread. */
  858         struct vnode *vp,               /* Mount point vnode. */
  859         int fsflags,                    /* Flags common to all filesystems. */
  860         struct vfsoptlist **optlist     /* Options local to the filesystem. */
  861         )
  862 {
  863         struct oexport_args oexport;
  864         struct export_args export;
  865         struct mount *mp;
  866         int error, export_error, flag;
  867 
  868         mtx_assert(&Giant, MA_OWNED);
  869         ASSERT_VOP_ELOCKED(vp, __func__);
  870         KASSERT((fsflags & MNT_UPDATE) != 0, ("MNT_UPDATE should be here"));
  871 
  872         if ((vp->v_vflag & VV_ROOT) == 0) {
  873                 vput(vp);
  874                 return (EINVAL);
  875         }
  876         mp = vp->v_mount;
  877         /*
  878          * We only allow the filesystem to be reloaded if it
  879          * is currently mounted read-only.
  880          */
  881         flag = mp->mnt_flag;
  882         if ((fsflags & MNT_RELOAD) != 0 && (flag & MNT_RDONLY) == 0) {
  883                 vput(vp);
  884                 return (EOPNOTSUPP);    /* Needs translation */
  885         }
  886         /*
  887          * Only privileged root, or (if MNT_USER is set) the user that
  888          * did the original mount is permitted to update it.
  889          */
  890         error = vfs_suser(mp, td);
  891         if (error != 0) {
  892                 vput(vp);
  893                 return (error);
  894         }
  895         if (vfs_busy(mp, MBF_NOWAIT)) {
  896                 vput(vp);
  897                 return (EBUSY);
  898         }
  899         VI_LOCK(vp);
  900         if ((vp->v_iflag & VI_MOUNT) != 0 || vp->v_mountedhere != NULL) {
  901                 VI_UNLOCK(vp);
  902                 vfs_unbusy(mp);
  903                 vput(vp);
  904                 return (EBUSY);
  905         }
  906         vp->v_iflag |= VI_MOUNT;
  907         VI_UNLOCK(vp);
  908         VOP_UNLOCK(vp, 0);
  909 
  910         MNT_ILOCK(mp);
  911         mp->mnt_flag &= ~MNT_UPDATEMASK;
  912         mp->mnt_flag |= fsflags & (MNT_RELOAD | MNT_FORCE | MNT_UPDATE |
  913             MNT_SNAPSHOT | MNT_ROOTFS | MNT_UPDATEMASK | MNT_RDONLY);
  914         if ((mp->mnt_flag & MNT_ASYNC) == 0)
  915                 mp->mnt_kern_flag &= ~MNTK_ASYNC;
  916         MNT_IUNLOCK(mp);
  917         mp->mnt_optnew = *optlist;
  918         vfs_mergeopts(mp->mnt_optnew, mp->mnt_opt);
  919 
  920         /*
  921          * Mount the filesystem.
  922          * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
  923          * get.  No freeing of cn_pnbuf.
  924          */
  925         error = VFS_MOUNT(mp);
  926 
  927         export_error = 0;
  928         if (error == 0) {
  929                 /* Process the export option. */
  930                 if (vfs_copyopt(mp->mnt_optnew, "export", &export,
  931                     sizeof(export)) == 0) {
  932                         export_error = vfs_export(mp, &export);
  933                 } else if (vfs_copyopt(mp->mnt_optnew, "export", &oexport,
  934                     sizeof(oexport)) == 0) {
  935                         export.ex_flags = oexport.ex_flags;
  936                         export.ex_root = oexport.ex_root;
  937                         export.ex_anon = oexport.ex_anon;
  938                         export.ex_addr = oexport.ex_addr;
  939                         export.ex_addrlen = oexport.ex_addrlen;
  940                         export.ex_mask = oexport.ex_mask;
  941                         export.ex_masklen = oexport.ex_masklen;
  942                         export.ex_indexfile = oexport.ex_indexfile;
  943                         export.ex_numsecflavors = 0;
  944                         export_error = vfs_export(mp, &export);
  945                 }
  946         }
  947 
  948         MNT_ILOCK(mp);
  949         if (error == 0) {
  950                 mp->mnt_flag &= ~(MNT_UPDATE | MNT_RELOAD | MNT_FORCE |
  951                     MNT_SNAPSHOT);
  952         } else {
  953                 /*
  954                  * If we fail, restore old mount flags. MNT_QUOTA is special,
  955                  * because it is not part of MNT_UPDATEMASK, but it could have
  956                  * changed in the meantime if quotactl(2) was called.
  957                  * All in all we want current value of MNT_QUOTA, not the old
  958                  * one.
  959                  */
  960                 mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA);
  961         }
  962         if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
  963                 mp->mnt_kern_flag |= MNTK_ASYNC;
  964         else
  965                 mp->mnt_kern_flag &= ~MNTK_ASYNC;
  966         MNT_IUNLOCK(mp);
  967 
  968         if (error != 0)
  969                 goto end;
  970 
  971         if (mp->mnt_opt != NULL)
  972                 vfs_freeopts(mp->mnt_opt);
  973         mp->mnt_opt = mp->mnt_optnew;
  974         *optlist = NULL;
  975         (void)VFS_STATFS(mp, &mp->mnt_stat);
  976         /*
  977          * Prevent external consumers of mount options from reading
  978          * mnt_optnew.
  979          */
  980         mp->mnt_optnew = NULL;
  981 
  982         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  983                 vfs_allocate_syncvnode(mp);
  984         else
  985                 vfs_deallocate_syncvnode(mp);
  986 end:
  987         vfs_unbusy(mp);
  988         VI_LOCK(vp);
  989         vp->v_iflag &= ~VI_MOUNT;
  990         VI_UNLOCK(vp);
  991         vrele(vp);
  992         return (error != 0 ? error : export_error);
  993 }
  994 
  995 /*
  996  * vfs_domount(): actually attempt a filesystem mount.
  997  */
  998 static int
  999 vfs_domount(
 1000         struct thread *td,              /* Calling thread. */
 1001         const char *fstype,             /* Filesystem type. */
 1002         char *fspath,                   /* Mount path. */
 1003         int fsflags,                    /* Flags common to all filesystems. */
 1004         struct vfsoptlist **optlist     /* Options local to the filesystem. */
 1005         )
 1006 {
 1007         struct vfsconf *vfsp;
 1008         struct nameidata nd;
 1009         struct vnode *vp;
 1010         int error;
 1011 
 1012         /*
 1013          * Be ultra-paranoid about making sure the type and fspath
 1014          * variables will fit in our mp buffers, including the
 1015          * terminating NUL.
 1016          */
 1017         if (strlen(fstype) >= MFSNAMELEN || strlen(fspath) >= MNAMELEN)
 1018                 return (ENAMETOOLONG);
 1019 
 1020         if (jailed(td->td_ucred) || usermount == 0) {
 1021                 if ((error = priv_check(td, PRIV_VFS_MOUNT)) != 0)
 1022                         return (error);
 1023         }
 1024 
 1025         /*
 1026          * Do not allow NFS export or MNT_SUIDDIR by unprivileged users.
 1027          */
 1028         if (fsflags & MNT_EXPORTED) {
 1029                 error = priv_check(td, PRIV_VFS_MOUNT_EXPORTED);
 1030                 if (error)
 1031                         return (error);
 1032         }
 1033         if (fsflags & MNT_SUIDDIR) {
 1034                 error = priv_check(td, PRIV_VFS_MOUNT_SUIDDIR);
 1035                 if (error)
 1036                         return (error);
 1037         }
 1038         /*
 1039          * Silently enforce MNT_NOSUID and MNT_USER for unprivileged users.
 1040          */
 1041         if ((fsflags & (MNT_NOSUID | MNT_USER)) != (MNT_NOSUID | MNT_USER)) {
 1042                 if (priv_check(td, PRIV_VFS_MOUNT_NONUSER) != 0)
 1043                         fsflags |= MNT_NOSUID | MNT_USER;
 1044         }
 1045 
 1046         /* Load KLDs before we lock the covered vnode to avoid reversals. */
 1047         vfsp = NULL;
 1048         if ((fsflags & MNT_UPDATE) == 0) {
 1049                 /* Don't try to load KLDs if we're mounting the root. */
 1050                 if (fsflags & MNT_ROOTFS)
 1051                         vfsp = vfs_byname(fstype);
 1052                 else
 1053                         vfsp = vfs_byname_kld(fstype, td, &error);
 1054                 if (vfsp == NULL)
 1055                         return (ENODEV);
 1056                 if (jailed(td->td_ucred) && !(vfsp->vfc_flags & VFCF_JAIL))
 1057                         return (EPERM);
 1058         }
 1059 
 1060         /*
 1061          * Get vnode to be covered or mount point's vnode in case of MNT_UPDATE.
 1062          */
 1063         NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | MPSAFE | AUDITVNODE1,
 1064             UIO_SYSSPACE, fspath, td);
 1065         error = namei(&nd);
 1066         if (error != 0)
 1067                 return (error);
 1068         if (!NDHASGIANT(&nd))
 1069                 mtx_lock(&Giant);
 1070         NDFREE(&nd, NDF_ONLY_PNBUF);
 1071         vp = nd.ni_vp;
 1072         if ((fsflags & MNT_UPDATE) == 0) {
 1073                 error = vfs_domount_first(td, vfsp, fspath, vp, fsflags,
 1074                     optlist);
 1075         } else {
 1076                 error = vfs_domount_update(td, vp, fsflags, optlist);
 1077         }
 1078         mtx_unlock(&Giant);
 1079 
 1080         ASSERT_VI_UNLOCKED(vp, __func__);
 1081         ASSERT_VOP_UNLOCKED(vp, __func__);
 1082 
 1083         return (error);
 1084 }
 1085 
 1086 /*
 1087  * Unmount a filesystem.
 1088  *
 1089  * Note: unmount takes a path to the vnode mounted on as argument, not
 1090  * special file (as before).
 1091  */
 1092 #ifndef _SYS_SYSPROTO_H_
 1093 struct unmount_args {
 1094         char    *path;
 1095         int     flags;
 1096 };
 1097 #endif
 1098 /* ARGSUSED */
 1099 int
 1100 sys_unmount(td, uap)
 1101         struct thread *td;
 1102         register struct unmount_args /* {
 1103                 char *path;
 1104                 int flags;
 1105         } */ *uap;
 1106 {
 1107         struct mount *mp;
 1108         char *pathbuf;
 1109         int error, id0, id1;
 1110 
 1111         AUDIT_ARG_VALUE(uap->flags);
 1112         if (jailed(td->td_ucred) || usermount == 0) {
 1113                 error = priv_check(td, PRIV_VFS_UNMOUNT);
 1114                 if (error)
 1115                         return (error);
 1116         }
 1117 
 1118         pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
 1119         error = copyinstr(uap->path, pathbuf, MNAMELEN, NULL);
 1120         if (error) {
 1121                 free(pathbuf, M_TEMP);
 1122                 return (error);
 1123         }
 1124         mtx_lock(&Giant);
 1125         if (uap->flags & MNT_BYFSID) {
 1126                 AUDIT_ARG_TEXT(pathbuf);
 1127                 /* Decode the filesystem ID. */
 1128                 if (sscanf(pathbuf, "FSID:%d:%d", &id0, &id1) != 2) {
 1129                         mtx_unlock(&Giant);
 1130                         free(pathbuf, M_TEMP);
 1131                         return (EINVAL);
 1132                 }
 1133 
 1134                 mtx_lock(&mountlist_mtx);
 1135                 TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
 1136                         if (mp->mnt_stat.f_fsid.val[0] == id0 &&
 1137                             mp->mnt_stat.f_fsid.val[1] == id1)
 1138                                 break;
 1139                 }
 1140                 mtx_unlock(&mountlist_mtx);
 1141         } else {
 1142                 AUDIT_ARG_UPATH1(td, pathbuf);
 1143                 mtx_lock(&mountlist_mtx);
 1144                 TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
 1145                         if (strcmp(mp->mnt_stat.f_mntonname, pathbuf) == 0)
 1146                                 break;
 1147                 }
 1148                 mtx_unlock(&mountlist_mtx);
 1149         }
 1150         free(pathbuf, M_TEMP);
 1151         if (mp == NULL) {
 1152                 /*
 1153                  * Previously we returned ENOENT for a nonexistent path and
 1154                  * EINVAL for a non-mountpoint.  We cannot tell these apart
 1155                  * now, so in the !MNT_BYFSID case return the more likely
 1156                  * EINVAL for compatibility.
 1157                  */
 1158                 mtx_unlock(&Giant);
 1159                 return ((uap->flags & MNT_BYFSID) ? ENOENT : EINVAL);
 1160         }
 1161 
 1162         /*
 1163          * Don't allow unmounting the root filesystem.
 1164          */
 1165         if (mp->mnt_flag & MNT_ROOTFS) {
 1166                 mtx_unlock(&Giant);
 1167                 return (EINVAL);
 1168         }
 1169         error = dounmount(mp, uap->flags, td);
 1170         mtx_unlock(&Giant);
 1171         return (error);
 1172 }
 1173 
 1174 /*
 1175  * Do the actual filesystem unmount.
 1176  */
 1177 int
 1178 dounmount(mp, flags, td)
 1179         struct mount *mp;
 1180         int flags;
 1181         struct thread *td;
 1182 {
 1183         struct vnode *coveredvp, *fsrootvp;
 1184         int error;
 1185         int async_flag;
 1186         int mnt_gen_r;
 1187 
 1188         mtx_assert(&Giant, MA_OWNED);
 1189 
 1190         if ((coveredvp = mp->mnt_vnodecovered) != NULL) {
 1191                 mnt_gen_r = mp->mnt_gen;
 1192                 VI_LOCK(coveredvp);
 1193                 vholdl(coveredvp);
 1194                 vn_lock(coveredvp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
 1195                 vdrop(coveredvp);
 1196                 /*
 1197                  * Check for mp being unmounted while waiting for the
 1198                  * covered vnode lock.
 1199                  */
 1200                 if (coveredvp->v_mountedhere != mp ||
 1201                     coveredvp->v_mountedhere->mnt_gen != mnt_gen_r) {
 1202                         VOP_UNLOCK(coveredvp, 0);
 1203                         return (EBUSY);
 1204                 }
 1205         }
 1206         /*
 1207          * Only privileged root, or (if MNT_USER is set) the user that did the
 1208          * original mount is permitted to unmount this filesystem.
 1209          */
 1210         error = vfs_suser(mp, td);
 1211         if (error) {
 1212                 if (coveredvp)
 1213                         VOP_UNLOCK(coveredvp, 0);
 1214                 return (error);
 1215         }
 1216 
 1217         MNT_ILOCK(mp);
 1218         if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
 1219                 MNT_IUNLOCK(mp);
 1220                 if (coveredvp)
 1221                         VOP_UNLOCK(coveredvp, 0);
 1222                 return (EBUSY);
 1223         }
 1224         mp->mnt_kern_flag |= MNTK_UNMOUNT | MNTK_NOINSMNTQ;
 1225         /* Allow filesystems to detect that a forced unmount is in progress. */
 1226         if (flags & MNT_FORCE)
 1227                 mp->mnt_kern_flag |= MNTK_UNMOUNTF;
 1228         error = 0;
 1229         if (mp->mnt_lockref) {
 1230                 mp->mnt_kern_flag |= MNTK_DRAINING;
 1231                 error = msleep(&mp->mnt_lockref, MNT_MTX(mp), PVFS,
 1232                     "mount drain", 0);
 1233         }
 1234         MNT_IUNLOCK(mp);
 1235         KASSERT(mp->mnt_lockref == 0,
 1236             ("%s: invalid lock refcount in the drain path @ %s:%d",
 1237             __func__, __FILE__, __LINE__));
 1238         KASSERT(error == 0,
 1239             ("%s: invalid return value for msleep in the drain path @ %s:%d",
 1240             __func__, __FILE__, __LINE__));
 1241         vn_start_write(NULL, &mp, V_WAIT);
 1242 
 1243         if (mp->mnt_flag & MNT_EXPUBLIC)
 1244                 vfs_setpublicfs(NULL, NULL, NULL);
 1245 
 1246         vfs_msync(mp, MNT_WAIT);
 1247         MNT_ILOCK(mp);
 1248         async_flag = mp->mnt_flag & MNT_ASYNC;
 1249         mp->mnt_flag &= ~MNT_ASYNC;
 1250         mp->mnt_kern_flag &= ~MNTK_ASYNC;
 1251         MNT_IUNLOCK(mp);
 1252         cache_purgevfs(mp);     /* remove cache entries for this file sys */
 1253         vfs_deallocate_syncvnode(mp);
 1254         /*
 1255          * For forced unmounts, move process cdir/rdir refs on the fs root
 1256          * vnode to the covered vnode.  For non-forced unmounts we want
 1257          * such references to cause an EBUSY error.
 1258          */
 1259         if ((flags & MNT_FORCE) &&
 1260             VFS_ROOT(mp, LK_EXCLUSIVE, &fsrootvp) == 0) {
 1261                 if (mp->mnt_vnodecovered != NULL)
 1262                         mountcheckdirs(fsrootvp, mp->mnt_vnodecovered);
 1263                 if (fsrootvp == rootvnode) {
 1264                         vrele(rootvnode);
 1265                         rootvnode = NULL;
 1266                 }
 1267                 vput(fsrootvp);
 1268         }
 1269         if (((mp->mnt_flag & MNT_RDONLY) ||
 1270              (error = VFS_SYNC(mp, MNT_WAIT)) == 0) || (flags & MNT_FORCE) != 0)
 1271                 error = VFS_UNMOUNT(mp, flags);
 1272         vn_finished_write(mp);
 1273         /*
 1274          * If we failed to flush the dirty blocks for this mount point,
 1275          * undo all the cdir/rdir and rootvnode changes we made above.
 1276          * Unless we failed to do so because the device is reporting that
 1277          * it doesn't exist anymore.
 1278          */
 1279         if (error && error != ENXIO) {
 1280                 if ((flags & MNT_FORCE) &&
 1281                     VFS_ROOT(mp, LK_EXCLUSIVE, &fsrootvp) == 0) {
 1282                         if (mp->mnt_vnodecovered != NULL)
 1283                                 mountcheckdirs(mp->mnt_vnodecovered, fsrootvp);
 1284                         if (rootvnode == NULL) {
 1285                                 rootvnode = fsrootvp;
 1286                                 vref(rootvnode);
 1287                         }
 1288                         vput(fsrootvp);
 1289                 }
 1290                 MNT_ILOCK(mp);
 1291                 mp->mnt_kern_flag &= ~MNTK_NOINSMNTQ;
 1292                 if ((mp->mnt_flag & MNT_RDONLY) == 0) {
 1293                         MNT_IUNLOCK(mp);
 1294                         vfs_allocate_syncvnode(mp);
 1295                         MNT_ILOCK(mp);
 1296                 }
 1297                 mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
 1298                 mp->mnt_flag |= async_flag;
 1299                 if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
 1300                         mp->mnt_kern_flag |= MNTK_ASYNC;
 1301                 if (mp->mnt_kern_flag & MNTK_MWAIT) {
 1302                         mp->mnt_kern_flag &= ~MNTK_MWAIT;
 1303                         wakeup(mp);
 1304                 }
 1305                 MNT_IUNLOCK(mp);
 1306                 if (coveredvp)
 1307                         VOP_UNLOCK(coveredvp, 0);
 1308                 return (error);
 1309         }
 1310         mtx_lock(&mountlist_mtx);
 1311         TAILQ_REMOVE(&mountlist, mp, mnt_list);
 1312         mtx_unlock(&mountlist_mtx);
 1313         if (coveredvp != NULL) {
 1314                 coveredvp->v_mountedhere = NULL;
 1315                 vput(coveredvp);
 1316         }
 1317         vfs_event_signal(NULL, VQ_UNMOUNT, 0);
 1318         vfs_mount_destroy(mp);
 1319         return (0);
 1320 }
 1321 
 1322 /*
 1323  * Report errors during filesystem mounting.
 1324  */
 1325 void
 1326 vfs_mount_error(struct mount *mp, const char *fmt, ...)
 1327 {
 1328         struct vfsoptlist *moptlist = mp->mnt_optnew;
 1329         va_list ap;
 1330         int error, len;
 1331         char *errmsg;
 1332 
 1333         error = vfs_getopt(moptlist, "errmsg", (void **)&errmsg, &len);
 1334         if (error || errmsg == NULL || len <= 0)
 1335                 return;
 1336 
 1337         va_start(ap, fmt);
 1338         vsnprintf(errmsg, (size_t)len, fmt, ap);
 1339         va_end(ap);
 1340 }
 1341 
 1342 void
 1343 vfs_opterror(struct vfsoptlist *opts, const char *fmt, ...)
 1344 {
 1345         va_list ap;
 1346         int error, len;
 1347         char *errmsg;
 1348 
 1349         error = vfs_getopt(opts, "errmsg", (void **)&errmsg, &len);
 1350         if (error || errmsg == NULL || len <= 0)
 1351                 return;
 1352 
 1353         va_start(ap, fmt);
 1354         vsnprintf(errmsg, (size_t)len, fmt, ap);
 1355         va_end(ap);
 1356 }
 1357 
 1358 /*
 1359  * ---------------------------------------------------------------------
 1360  * Functions for querying mount options/arguments from filesystems.
 1361  */
 1362 
 1363 /*
 1364  * Check that no unknown options are given
 1365  */
 1366 int
 1367 vfs_filteropt(struct vfsoptlist *opts, const char **legal)
 1368 {
 1369         struct vfsopt *opt;
 1370         char errmsg[255];
 1371         const char **t, *p, *q;
 1372         int ret = 0;
 1373 
 1374         TAILQ_FOREACH(opt, opts, link) {
 1375                 p = opt->name;
 1376                 q = NULL;
 1377                 if (p[0] == 'n' && p[1] == 'o')
 1378                         q = p + 2;
 1379                 for(t = global_opts; *t != NULL; t++) {
 1380                         if (strcmp(*t, p) == 0)
 1381                                 break;
 1382                         if (q != NULL) {
 1383                                 if (strcmp(*t, q) == 0)
 1384                                         break;
 1385                         }
 1386                 }
 1387                 if (*t != NULL)
 1388                         continue;
 1389                 for(t = legal; *t != NULL; t++) {
 1390                         if (strcmp(*t, p) == 0)
 1391                                 break;
 1392                         if (q != NULL) {
 1393                                 if (strcmp(*t, q) == 0)
 1394                                         break;
 1395                         }
 1396                 }
 1397                 if (*t != NULL)
 1398                         continue;
 1399                 snprintf(errmsg, sizeof(errmsg),
 1400                     "mount option <%s> is unknown", p);
 1401                 ret = EINVAL;
 1402         }
 1403         if (ret != 0) {
 1404                 TAILQ_FOREACH(opt, opts, link) {
 1405                         if (strcmp(opt->name, "errmsg") == 0) {
 1406                                 strncpy((char *)opt->value, errmsg, opt->len);
 1407                                 break;
 1408                         }
 1409                 }
 1410                 if (opt == NULL)
 1411                         printf("%s\n", errmsg);
 1412         }
 1413         return (ret);
 1414 }
 1415 
 1416 /*
 1417  * Get a mount option by its name.
 1418  *
 1419  * Return 0 if the option was found, ENOENT otherwise.
 1420  * If len is non-NULL it will be filled with the length
 1421  * of the option. If buf is non-NULL, it will be filled
 1422  * with the address of the option.
 1423  */
 1424 int
 1425 vfs_getopt(opts, name, buf, len)
 1426         struct vfsoptlist *opts;
 1427         const char *name;
 1428         void **buf;
 1429         int *len;
 1430 {
 1431         struct vfsopt *opt;
 1432 
 1433         KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
 1434 
 1435         TAILQ_FOREACH(opt, opts, link) {
 1436                 if (strcmp(name, opt->name) == 0) {
 1437                         opt->seen = 1;
 1438                         if (len != NULL)
 1439                                 *len = opt->len;
 1440                         if (buf != NULL)
 1441                                 *buf = opt->value;
 1442                         return (0);
 1443                 }
 1444         }
 1445         return (ENOENT);
 1446 }
 1447 
 1448 int
 1449 vfs_getopt_pos(struct vfsoptlist *opts, const char *name)
 1450 {
 1451         struct vfsopt *opt;
 1452 
 1453         if (opts == NULL)
 1454                 return (-1);
 1455 
 1456         TAILQ_FOREACH(opt, opts, link) {
 1457                 if (strcmp(name, opt->name) == 0) {
 1458                         opt->seen = 1;
 1459                         return (opt->pos);
 1460                 }
 1461         }
 1462         return (-1);
 1463 }
 1464 
 1465 char *
 1466 vfs_getopts(struct vfsoptlist *opts, const char *name, int *error)
 1467 {
 1468         struct vfsopt *opt;
 1469 
 1470         *error = 0;
 1471         TAILQ_FOREACH(opt, opts, link) {
 1472                 if (strcmp(name, opt->name) != 0)
 1473                         continue;
 1474                 opt->seen = 1;
 1475                 if (opt->len == 0 ||
 1476                     ((char *)opt->value)[opt->len - 1] != '\0') {
 1477                         *error = EINVAL;
 1478                         return (NULL);
 1479                 }
 1480                 return (opt->value);
 1481         }
 1482         *error = ENOENT;
 1483         return (NULL);
 1484 }
 1485 
 1486 int
 1487 vfs_flagopt(struct vfsoptlist *opts, const char *name, uint64_t *w,
 1488         uint64_t val)
 1489 {
 1490         struct vfsopt *opt;
 1491 
 1492         TAILQ_FOREACH(opt, opts, link) {
 1493                 if (strcmp(name, opt->name) == 0) {
 1494                         opt->seen = 1;
 1495                         if (w != NULL)
 1496                                 *w |= val;
 1497                         return (1);
 1498                 }
 1499         }
 1500         if (w != NULL)
 1501                 *w &= ~val;
 1502         return (0);
 1503 }
 1504 
 1505 int
 1506 vfs_scanopt(struct vfsoptlist *opts, const char *name, const char *fmt, ...)
 1507 {
 1508         va_list ap;
 1509         struct vfsopt *opt;
 1510         int ret;
 1511 
 1512         KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
 1513 
 1514         TAILQ_FOREACH(opt, opts, link) {
 1515                 if (strcmp(name, opt->name) != 0)
 1516                         continue;
 1517                 opt->seen = 1;
 1518                 if (opt->len == 0 || opt->value == NULL)
 1519                         return (0);
 1520                 if (((char *)opt->value)[opt->len - 1] != '\0')
 1521                         return (0);
 1522                 va_start(ap, fmt);
 1523                 ret = vsscanf(opt->value, fmt, ap);
 1524                 va_end(ap);
 1525                 return (ret);
 1526         }
 1527         return (0);
 1528 }
 1529 
 1530 int
 1531 vfs_setopt(struct vfsoptlist *opts, const char *name, void *value, int len)
 1532 {
 1533         struct vfsopt *opt;
 1534 
 1535         TAILQ_FOREACH(opt, opts, link) {
 1536                 if (strcmp(name, opt->name) != 0)
 1537                         continue;
 1538                 opt->seen = 1;
 1539                 if (opt->value == NULL)
 1540                         opt->len = len;
 1541                 else {
 1542                         if (opt->len != len)
 1543                                 return (EINVAL);
 1544                         bcopy(value, opt->value, len);
 1545                 }
 1546                 return (0);
 1547         }
 1548         return (ENOENT);
 1549 }
 1550 
 1551 int
 1552 vfs_setopt_part(struct vfsoptlist *opts, const char *name, void *value, int len)
 1553 {
 1554         struct vfsopt *opt;
 1555 
 1556         TAILQ_FOREACH(opt, opts, link) {
 1557                 if (strcmp(name, opt->name) != 0)
 1558                         continue;
 1559                 opt->seen = 1;
 1560                 if (opt->value == NULL)
 1561                         opt->len = len;
 1562                 else {
 1563                         if (opt->len < len)
 1564                                 return (EINVAL);
 1565                         opt->len = len;
 1566                         bcopy(value, opt->value, len);
 1567                 }
 1568                 return (0);
 1569         }
 1570         return (ENOENT);
 1571 }
 1572 
 1573 int
 1574 vfs_setopts(struct vfsoptlist *opts, const char *name, const char *value)
 1575 {
 1576         struct vfsopt *opt;
 1577 
 1578         TAILQ_FOREACH(opt, opts, link) {
 1579                 if (strcmp(name, opt->name) != 0)
 1580                         continue;
 1581                 opt->seen = 1;
 1582                 if (opt->value == NULL)
 1583                         opt->len = strlen(value) + 1;
 1584                 else if (strlcpy(opt->value, value, opt->len) >= opt->len)
 1585                         return (EINVAL);
 1586                 return (0);
 1587         }
 1588         return (ENOENT);
 1589 }
 1590 
 1591 /*
 1592  * Find and copy a mount option.
 1593  *
 1594  * The size of the buffer has to be specified
 1595  * in len, if it is not the same length as the
 1596  * mount option, EINVAL is returned.
 1597  * Returns ENOENT if the option is not found.
 1598  */
 1599 int
 1600 vfs_copyopt(opts, name, dest, len)
 1601         struct vfsoptlist *opts;
 1602         const char *name;
 1603         void *dest;
 1604         int len;
 1605 {
 1606         struct vfsopt *opt;
 1607 
 1608         KASSERT(opts != NULL, ("vfs_copyopt: caller passed 'opts' as NULL"));
 1609 
 1610         TAILQ_FOREACH(opt, opts, link) {
 1611                 if (strcmp(name, opt->name) == 0) {
 1612                         opt->seen = 1;
 1613                         if (len != opt->len)
 1614                                 return (EINVAL);
 1615                         bcopy(opt->value, dest, opt->len);
 1616                         return (0);
 1617                 }
 1618         }
 1619         return (ENOENT);
 1620 }
 1621 
 1622 /*
 1623  * This is a helper function for filesystems to traverse their
 1624  * vnodes.  See MNT_VNODE_FOREACH() in sys/mount.h
 1625  */
 1626 
 1627 struct vnode *
 1628 __mnt_vnode_next(struct vnode **mvp, struct mount *mp)
 1629 {
 1630         struct vnode *vp;
 1631 
 1632         mtx_assert(MNT_MTX(mp), MA_OWNED);
 1633 
 1634         KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
 1635         if (should_yield()) {
 1636                 MNT_IUNLOCK(mp);
 1637                 kern_yield(PRI_UNCHANGED);
 1638                 MNT_ILOCK(mp);
 1639         }
 1640         vp = TAILQ_NEXT(*mvp, v_nmntvnodes);
 1641         while (vp != NULL && vp->v_type == VMARKER)
 1642                 vp = TAILQ_NEXT(vp, v_nmntvnodes);
 1643 
 1644         /* Check if we are done */
 1645         if (vp == NULL) {
 1646                 __mnt_vnode_markerfree(mvp, mp);
 1647                 return (NULL);
 1648         }
 1649         TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes);
 1650         TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
 1651         return (vp);
 1652 }
 1653 
 1654 struct vnode *
 1655 __mnt_vnode_first(struct vnode **mvp, struct mount *mp)
 1656 {
 1657         struct vnode *vp;
 1658 
 1659         mtx_assert(MNT_MTX(mp), MA_OWNED);
 1660 
 1661         vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
 1662         while (vp != NULL && vp->v_type == VMARKER)
 1663                 vp = TAILQ_NEXT(vp, v_nmntvnodes);
 1664 
 1665         /* Check if we are done */
 1666         if (vp == NULL) {
 1667                 *mvp = NULL;
 1668                 return (NULL);
 1669         }
 1670         MNT_REF(mp);
 1671         MNT_IUNLOCK(mp);
 1672         *mvp = (struct vnode *) malloc(sizeof(struct vnode),
 1673                                        M_VNODE_MARKER,
 1674                                        M_WAITOK | M_ZERO);
 1675         MNT_ILOCK(mp);
 1676         (*mvp)->v_type = VMARKER;
 1677 
 1678         vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
 1679         while (vp != NULL && vp->v_type == VMARKER)
 1680                 vp = TAILQ_NEXT(vp, v_nmntvnodes);
 1681 
 1682         /* Check if we are done */
 1683         if (vp == NULL) {
 1684                 MNT_IUNLOCK(mp);
 1685                 free(*mvp, M_VNODE_MARKER);
 1686                 MNT_ILOCK(mp);
 1687                 *mvp = NULL;
 1688                 MNT_REL(mp);
 1689                 return (NULL);
 1690         }
 1691         (*mvp)->v_mount = mp;
 1692         TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
 1693         return (vp);
 1694 }
 1695 
 1696 
 1697 void
 1698 __mnt_vnode_markerfree(struct vnode **mvp, struct mount *mp)
 1699 {
 1700 
 1701         if (*mvp == NULL)
 1702                 return;
 1703 
 1704         mtx_assert(MNT_MTX(mp), MA_OWNED);
 1705 
 1706         KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
 1707         TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes);
 1708         MNT_IUNLOCK(mp);
 1709         free(*mvp, M_VNODE_MARKER);
 1710         MNT_ILOCK(mp);
 1711         *mvp = NULL;
 1712         MNT_REL(mp);
 1713 }
 1714 
 1715 
 1716 int
 1717 __vfs_statfs(struct mount *mp, struct statfs *sbp)
 1718 {
 1719         int error;
 1720 
 1721         error = mp->mnt_op->vfs_statfs(mp, &mp->mnt_stat);
 1722         if (sbp != &mp->mnt_stat)
 1723                 *sbp = mp->mnt_stat;
 1724         return (error);
 1725 }
 1726 
 1727 void
 1728 vfs_mountedfrom(struct mount *mp, const char *from)
 1729 {
 1730 
 1731         bzero(mp->mnt_stat.f_mntfromname, sizeof mp->mnt_stat.f_mntfromname);
 1732         strlcpy(mp->mnt_stat.f_mntfromname, from,
 1733             sizeof mp->mnt_stat.f_mntfromname);
 1734 }
 1735 
 1736 /*
 1737  * ---------------------------------------------------------------------
 1738  * This is the api for building mount args and mounting filesystems from
 1739  * inside the kernel.
 1740  *
 1741  * The API works by accumulation of individual args.  First error is
 1742  * latched.
 1743  *
 1744  * XXX: should be documented in new manpage kernel_mount(9)
 1745  */
 1746 
 1747 /* A memory allocation which must be freed when we are done */
 1748 struct mntaarg {
 1749         SLIST_ENTRY(mntaarg)    next;
 1750 };
 1751 
 1752 /* The header for the mount arguments */
 1753 struct mntarg {
 1754         struct iovec *v;
 1755         int len;
 1756         int error;
 1757         SLIST_HEAD(, mntaarg)   list;
 1758 };
 1759 
 1760 /*
 1761  * Add a boolean argument.
 1762  *
 1763  * flag is the boolean value.
 1764  * name must start with "no".
 1765  */
 1766 struct mntarg *
 1767 mount_argb(struct mntarg *ma, int flag, const char *name)
 1768 {
 1769 
 1770         KASSERT(name[0] == 'n' && name[1] == 'o',
 1771             ("mount_argb(...,%s): name must start with 'no'", name));
 1772 
 1773         return (mount_arg(ma, name + (flag ? 2 : 0), NULL, 0));
 1774 }
 1775 
 1776 /*
 1777  * Add an argument printf style
 1778  */
 1779 struct mntarg *
 1780 mount_argf(struct mntarg *ma, const char *name, const char *fmt, ...)
 1781 {
 1782         va_list ap;
 1783         struct mntaarg *maa;
 1784         struct sbuf *sb;
 1785         int len;
 1786 
 1787         if (ma == NULL) {
 1788                 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
 1789                 SLIST_INIT(&ma->list);
 1790         }
 1791         if (ma->error)
 1792                 return (ma);
 1793 
 1794         ma->v = realloc(ma->v, sizeof *ma->v * (ma->len + 2),
 1795             M_MOUNT, M_WAITOK);
 1796         ma->v[ma->len].iov_base = (void *)(uintptr_t)name;
 1797         ma->v[ma->len].iov_len = strlen(name) + 1;
 1798         ma->len++;
 1799 
 1800         sb = sbuf_new_auto();
 1801         va_start(ap, fmt);
 1802         sbuf_vprintf(sb, fmt, ap);
 1803         va_end(ap);
 1804         sbuf_finish(sb);
 1805         len = sbuf_len(sb) + 1;
 1806         maa = malloc(sizeof *maa + len, M_MOUNT, M_WAITOK | M_ZERO);
 1807         SLIST_INSERT_HEAD(&ma->list, maa, next);
 1808         bcopy(sbuf_data(sb), maa + 1, len);
 1809         sbuf_delete(sb);
 1810 
 1811         ma->v[ma->len].iov_base = maa + 1;
 1812         ma->v[ma->len].iov_len = len;
 1813         ma->len++;
 1814 
 1815         return (ma);
 1816 }
 1817 
 1818 /*
 1819  * Add an argument which is a userland string.
 1820  */
 1821 struct mntarg *
 1822 mount_argsu(struct mntarg *ma, const char *name, const void *val, int len)
 1823 {
 1824         struct mntaarg *maa;
 1825         char *tbuf;
 1826 
 1827         if (val == NULL)
 1828                 return (ma);
 1829         if (ma == NULL) {
 1830                 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
 1831                 SLIST_INIT(&ma->list);
 1832         }
 1833         if (ma->error)
 1834                 return (ma);
 1835         maa = malloc(sizeof *maa + len, M_MOUNT, M_WAITOK | M_ZERO);
 1836         SLIST_INSERT_HEAD(&ma->list, maa, next);
 1837         tbuf = (void *)(maa + 1);
 1838         ma->error = copyinstr(val, tbuf, len, NULL);
 1839         return (mount_arg(ma, name, tbuf, -1));
 1840 }
 1841 
 1842 /*
 1843  * Plain argument.
 1844  *
 1845  * If length is -1, treat value as a C string.
 1846  */
 1847 struct mntarg *
 1848 mount_arg(struct mntarg *ma, const char *name, const void *val, int len)
 1849 {
 1850 
 1851         if (ma == NULL) {
 1852                 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
 1853                 SLIST_INIT(&ma->list);
 1854         }
 1855         if (ma->error)
 1856                 return (ma);
 1857 
 1858         ma->v = realloc(ma->v, sizeof *ma->v * (ma->len + 2),
 1859             M_MOUNT, M_WAITOK);
 1860         ma->v[ma->len].iov_base = (void *)(uintptr_t)name;
 1861         ma->v[ma->len].iov_len = strlen(name) + 1;
 1862         ma->len++;
 1863 
 1864         ma->v[ma->len].iov_base = (void *)(uintptr_t)val;
 1865         if (len < 0)
 1866                 ma->v[ma->len].iov_len = strlen(val) + 1;
 1867         else
 1868                 ma->v[ma->len].iov_len = len;
 1869         ma->len++;
 1870         return (ma);
 1871 }
 1872 
 1873 /*
 1874  * Free a mntarg structure
 1875  */
 1876 static void
 1877 free_mntarg(struct mntarg *ma)
 1878 {
 1879         struct mntaarg *maa;
 1880 
 1881         while (!SLIST_EMPTY(&ma->list)) {
 1882                 maa = SLIST_FIRST(&ma->list);
 1883                 SLIST_REMOVE_HEAD(&ma->list, next);
 1884                 free(maa, M_MOUNT);
 1885         }
 1886         free(ma->v, M_MOUNT);
 1887         free(ma, M_MOUNT);
 1888 }
 1889 
 1890 /*
 1891  * Mount a filesystem
 1892  */
 1893 int
 1894 kernel_mount(struct mntarg *ma, int flags)
 1895 {
 1896         struct uio auio;
 1897         int error;
 1898 
 1899         KASSERT(ma != NULL, ("kernel_mount NULL ma"));
 1900         KASSERT(ma->v != NULL, ("kernel_mount NULL ma->v"));
 1901         KASSERT(!(ma->len & 1), ("kernel_mount odd ma->len (%d)", ma->len));
 1902 
 1903         auio.uio_iov = ma->v;
 1904         auio.uio_iovcnt = ma->len;
 1905         auio.uio_segflg = UIO_SYSSPACE;
 1906 
 1907         error = ma->error;
 1908         if (!error)
 1909                 error = vfs_donmount(curthread, flags, &auio);
 1910         free_mntarg(ma);
 1911         return (error);
 1912 }
 1913 
 1914 /*
 1915  * A printflike function to mount a filesystem.
 1916  */
 1917 int
 1918 kernel_vmount(int flags, ...)
 1919 {
 1920         struct mntarg *ma = NULL;
 1921         va_list ap;
 1922         const char *cp;
 1923         const void *vp;
 1924         int error;
 1925 
 1926         va_start(ap, flags);
 1927         for (;;) {
 1928                 cp = va_arg(ap, const char *);
 1929                 if (cp == NULL)
 1930                         break;
 1931                 vp = va_arg(ap, const void *);
 1932                 ma = mount_arg(ma, cp, vp, (vp != NULL ? -1 : 0));
 1933         }
 1934         va_end(ap);
 1935 
 1936         error = kernel_mount(ma, flags);
 1937         return (error);
 1938 }
 1939 
 1940 void
 1941 vfs_oexport_conv(const struct oexport_args *oexp, struct export_args *exp)
 1942 {
 1943 
 1944         bcopy(oexp, exp, sizeof(*oexp));
 1945         exp->ex_numsecflavors = 0;
 1946 }

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