devfs_vfsops.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 1992, 1993, 1995
    5  *      The Regents of the University of California.  All rights reserved.
    6  * Copyright (c) 2000
    7  *      Poul-Henning Kamp.  All rights reserved.
    8  *
    9  * This code is derived from software donated to Berkeley by
   10  * Jan-Simon Pendry.
   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. Neither the name of the University nor the names of its contributors
   18  *    may be used to endorse or promote products derived from this software
   19  *    without specific prior written permission.
   20  *
   21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31  * SUCH DAMAGE.
   32  *
   33  *      @(#)kernfs_vfsops.c     8.10 (Berkeley) 5/14/95
   34  * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
   35  *
   36  * $FreeBSD$
   37  */
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/kernel.h>
   42 #include <sys/lock.h>
   43 #include <sys/malloc.h>
   44 #include <sys/mount.h>
   45 #include <sys/proc.h>
   46 #include <sys/sx.h>
   47 #include <sys/vnode.h>
   48 #include <sys/limits.h>
   49 #include <sys/jail.h>
   50 
   51 #include <fs/devfs/devfs.h>
   52 
   53 static struct unrhdr    *devfs_unr;
   54 
   55 MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
   56 
   57 static vfs_mount_t      devfs_mount;
   58 static vfs_unmount_t    devfs_unmount;
   59 static vfs_root_t       devfs_root;
   60 static vfs_statfs_t     devfs_statfs;
   61 
   62 static const char *devfs_opts[] = {
   63         "from", "export", "ruleset", NULL
   64 };
   65 
   66 /*
   67  * Mount the filesystem
   68  */
   69 static int
   70 devfs_mount(struct mount *mp)
   71 {
   72         int error;
   73         struct devfs_mount *fmp;
   74         struct vnode *rvp;
   75         struct thread *td = curthread;
   76         int injail, rsnum;
   77 
   78         if (devfs_unr == NULL)
   79                 devfs_unr = new_unrhdr(0, INT_MAX, NULL);
   80 
   81         error = 0;
   82 
   83         if (mp->mnt_flag & MNT_ROOTFS)
   84                 return (EOPNOTSUPP);
   85 
   86         rsnum = 0;
   87         injail = jailed(td->td_ucred);
   88 
   89         if (mp->mnt_optnew != NULL) {
   90                 if (vfs_filteropt(mp->mnt_optnew, devfs_opts))
   91                         return (EINVAL);
   92 
   93                 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
   94                         return (EOPNOTSUPP);
   95 
   96                 if (vfs_getopt(mp->mnt_optnew, "ruleset", NULL, NULL) == 0 &&
   97                     (vfs_scanopt(mp->mnt_optnew, "ruleset", "%d",
   98                     &rsnum) != 1 || rsnum < 0 || rsnum > 65535)) {
   99                         vfs_mount_error(mp, "%s",
  100                             "invalid ruleset specification");
  101                         return (EINVAL);
  102                 }
  103 
  104                 if (injail && rsnum != 0 &&
  105                     rsnum != td->td_ucred->cr_prison->pr_devfs_rsnum)
  106                         return (EPERM);
  107         }
  108 
  109         /* jails enforce their ruleset */
  110         if (injail)
  111                 rsnum = td->td_ucred->cr_prison->pr_devfs_rsnum;
  112 
  113         if (mp->mnt_flag & MNT_UPDATE) {
  114                 if (rsnum != 0) {
  115                         fmp = mp->mnt_data;
  116                         if (fmp != NULL) {
  117                                 sx_xlock(&fmp->dm_lock);
  118                                 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
  119                                 devfs_ruleset_apply(fmp);
  120                                 sx_xunlock(&fmp->dm_lock);
  121                         }
  122                 }
  123                 return (0);
  124         }
  125 
  126         fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO);
  127         fmp->dm_idx = alloc_unr(devfs_unr);
  128         sx_init(&fmp->dm_lock, "devfsmount");
  129         fmp->dm_holdcnt = 1;
  130 
  131         MNT_ILOCK(mp);
  132         mp->mnt_flag |= MNT_LOCAL;
  133         mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED;
  134 #ifdef MAC
  135         mp->mnt_flag |= MNT_MULTILABEL;
  136 #endif
  137         MNT_IUNLOCK(mp);
  138         fmp->dm_mount = mp;
  139         mp->mnt_data = (void *) fmp;
  140         vfs_getnewfsid(mp);
  141 
  142         fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO);
  143 
  144         error = devfs_root(mp, LK_EXCLUSIVE, &rvp);
  145         if (error) {
  146                 sx_destroy(&fmp->dm_lock);
  147                 free_unr(devfs_unr, fmp->dm_idx);
  148                 free(fmp, M_DEVFS);
  149                 return (error);
  150         }
  151 
  152         if (rsnum != 0) {
  153                 sx_xlock(&fmp->dm_lock);
  154                 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
  155                 sx_xunlock(&fmp->dm_lock);
  156         }
  157 
  158         VOP_UNLOCK(rvp, 0);
  159 
  160         vfs_mountedfrom(mp, "devfs");
  161 
  162         return (0);
  163 }
  164 
  165 void
  166 devfs_unmount_final(struct devfs_mount *fmp)
  167 {
  168         sx_destroy(&fmp->dm_lock);
  169         free(fmp, M_DEVFS);
  170 }
  171 
  172 static int
  173 devfs_unmount(struct mount *mp, int mntflags)
  174 {
  175         int error;
  176         int flags = 0;
  177         struct devfs_mount *fmp;
  178         int hold;
  179         u_int idx;
  180 
  181         fmp = VFSTODEVFS(mp);
  182         KASSERT(fmp->dm_mount != NULL,
  183                 ("devfs_unmount unmounted devfs_mount"));
  184         if (mntflags & MNT_FORCE)
  185                 flags |= FORCECLOSE;
  186         /* There is 1 extra root vnode reference from devfs_mount(). */
  187         error = vflush(mp, 1, flags, curthread);
  188         if (error)
  189                 return (error);
  190         sx_xlock(&fmp->dm_lock);
  191         devfs_cleanup(fmp);
  192         devfs_rules_cleanup(fmp);
  193         fmp->dm_mount = NULL;
  194         hold = --fmp->dm_holdcnt;
  195         mp->mnt_data = NULL;
  196         idx = fmp->dm_idx;
  197         sx_xunlock(&fmp->dm_lock);
  198         free_unr(devfs_unr, idx);
  199         if (hold == 0)
  200                 devfs_unmount_final(fmp);
  201         return 0;
  202 }
  203 
  204 /* Return locked reference to root.  */
  205 
  206 static int
  207 devfs_root(struct mount *mp, int flags, struct vnode **vpp)
  208 {
  209         int error;
  210         struct vnode *vp;
  211         struct devfs_mount *dmp;
  212 
  213         dmp = VFSTODEVFS(mp);
  214         sx_xlock(&dmp->dm_lock);
  215         error = devfs_allocv(dmp->dm_rootdir, mp, LK_EXCLUSIVE, &vp);
  216         if (error)
  217                 return (error);
  218         vp->v_vflag |= VV_ROOT;
  219         *vpp = vp;
  220         return (0);
  221 }
  222 
  223 static int
  224 devfs_statfs(struct mount *mp, struct statfs *sbp)
  225 {
  226 
  227         sbp->f_flags = 0;
  228         sbp->f_bsize = DEV_BSIZE;
  229         sbp->f_iosize = DEV_BSIZE;
  230         sbp->f_blocks = 2;              /* 1K to keep df happy */
  231         sbp->f_bfree = 0;
  232         sbp->f_bavail = 0;
  233         sbp->f_files = 0;
  234         sbp->f_ffree = 0;
  235         return (0);
  236 }
  237 
  238 static struct vfsops devfs_vfsops = {
  239         .vfs_mount =            devfs_mount,
  240         .vfs_root =             devfs_root,
  241         .vfs_statfs =           devfs_statfs,
  242         .vfs_unmount =          devfs_unmount,
  243 };
  244 
  245 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL);

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FreeBSD/Linux Kernel Cross Reference sys/fs/devfs/devfs_vfsops.c

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sys/fs/devfs/devfs_vfsops.c