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


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

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    1 /*-
    2  * Copyright (c) 1992, 1993, 1995
    3  *      The Regents of the University of California.  All rights reserved.
    4  * Copyright (c) 2000
    5  *      Poul-Henning Kamp.  All rights reserved.
    6  *
    7  * This code is derived from software donated to Berkeley by
    8  * Jan-Simon Pendry.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Neither the name of the University nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  *
   31  *      @(#)kernfs_vfsops.c     8.10 (Berkeley) 5/14/95
   32  * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
   33  *
   34  * $FreeBSD: releng/11.0/sys/fs/devfs/devfs_vfsops.c 287109 2015-08-24 14:04:44Z trasz $
   35  */
   36 
   37 #include <sys/param.h>
   38 #include <sys/systm.h>
   39 #include <sys/kernel.h>
   40 #include <sys/lock.h>
   41 #include <sys/malloc.h>
   42 #include <sys/mount.h>
   43 #include <sys/proc.h>
   44 #include <sys/sx.h>
   45 #include <sys/vnode.h>
   46 #include <sys/limits.h>
   47 #include <sys/jail.h>
   48 
   49 #include <fs/devfs/devfs.h>
   50 
   51 static struct unrhdr    *devfs_unr;
   52 
   53 MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
   54 
   55 static vfs_mount_t      devfs_mount;
   56 static vfs_unmount_t    devfs_unmount;
   57 static vfs_root_t       devfs_root;
   58 static vfs_statfs_t     devfs_statfs;
   59 
   60 static const char *devfs_opts[] = {
   61         "from", "export", "ruleset", NULL
   62 };
   63 
   64 /*
   65  * Mount the filesystem
   66  */
   67 static int
   68 devfs_mount(struct mount *mp)
   69 {
   70         int error;
   71         struct devfs_mount *fmp;
   72         struct vnode *rvp;
   73         struct thread *td = curthread;
   74         int injail, rsnum;
   75 
   76         if (devfs_unr == NULL)
   77                 devfs_unr = new_unrhdr(0, INT_MAX, NULL);
   78 
   79         error = 0;
   80 
   81         if (mp->mnt_flag & MNT_ROOTFS)
   82                 return (EOPNOTSUPP);
   83 
   84         if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_DEVFS))
   85                 return (EPERM);
   86 
   87         rsnum = 0;
   88         injail = jailed(td->td_ucred);
   89 
   90         if (mp->mnt_optnew != NULL) {
   91                 if (vfs_filteropt(mp->mnt_optnew, devfs_opts))
   92                         return (EINVAL);
   93 
   94                 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
   95                         return (EOPNOTSUPP);
   96 
   97                 if (vfs_getopt(mp->mnt_optnew, "ruleset", NULL, NULL) == 0 &&
   98                     (vfs_scanopt(mp->mnt_optnew, "ruleset", "%d",
   99                     &rsnum) != 1 || rsnum < 0 || rsnum > 65535)) {
  100                         vfs_mount_error(mp, "%s",
  101                             "invalid ruleset specification");
  102                         return (EINVAL);
  103                 }
  104 
  105                 if (injail && rsnum != 0 &&
  106                     rsnum != td->td_ucred->cr_prison->pr_devfs_rsnum)
  107                         return (EPERM);
  108         }
  109 
  110         /* jails enforce their ruleset */
  111         if (injail)
  112                 rsnum = td->td_ucred->cr_prison->pr_devfs_rsnum;
  113 
  114         if (mp->mnt_flag & MNT_UPDATE) {
  115                 if (rsnum != 0) {
  116                         fmp = mp->mnt_data;
  117                         if (fmp != NULL) {
  118                                 sx_xlock(&fmp->dm_lock);
  119                                 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
  120                                 devfs_ruleset_apply(fmp);
  121                                 sx_xunlock(&fmp->dm_lock);
  122                         }
  123                 }
  124                 return (0);
  125         }
  126 
  127         fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO);
  128         fmp->dm_idx = alloc_unr(devfs_unr);
  129         sx_init(&fmp->dm_lock, "devfsmount");
  130         fmp->dm_holdcnt = 1;
  131 
  132         MNT_ILOCK(mp);
  133         mp->mnt_flag |= MNT_LOCAL;
  134         mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED;
  135 #ifdef MAC
  136         mp->mnt_flag |= MNT_MULTILABEL;
  137 #endif
  138         MNT_IUNLOCK(mp);
  139         fmp->dm_mount = mp;
  140         mp->mnt_data = (void *) fmp;
  141         vfs_getnewfsid(mp);
  142 
  143         fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO);
  144 
  145         error = devfs_root(mp, LK_EXCLUSIVE, &rvp);
  146         if (error) {
  147                 sx_destroy(&fmp->dm_lock);
  148                 free_unr(devfs_unr, fmp->dm_idx);
  149                 free(fmp, M_DEVFS);
  150                 return (error);
  151         }
  152 
  153         if (rsnum != 0) {
  154                 sx_xlock(&fmp->dm_lock);
  155                 devfs_ruleset_set((devfs_rsnum)rsnum, fmp);
  156                 sx_xunlock(&fmp->dm_lock);
  157         }
  158 
  159         VOP_UNLOCK(rvp, 0);
  160 
  161         vfs_mountedfrom(mp, "devfs");
  162 
  163         return (0);
  164 }
  165 
  166 void
  167 devfs_unmount_final(struct devfs_mount *fmp)
  168 {
  169         sx_destroy(&fmp->dm_lock);
  170         free(fmp, M_DEVFS);
  171 }
  172 
  173 static int
  174 devfs_unmount(struct mount *mp, int mntflags)
  175 {
  176         int error;
  177         int flags = 0;
  178         struct devfs_mount *fmp;
  179         int hold;
  180         u_int idx;
  181 
  182         fmp = VFSTODEVFS(mp);
  183         KASSERT(fmp->dm_mount != NULL,
  184                 ("devfs_unmount unmounted devfs_mount"));
  185         if (mntflags & MNT_FORCE)
  186                 flags |= FORCECLOSE;
  187         /* There is 1 extra root vnode reference from devfs_mount(). */
  188         error = vflush(mp, 1, flags, curthread);
  189         if (error)
  190                 return (error);
  191         sx_xlock(&fmp->dm_lock);
  192         devfs_cleanup(fmp);
  193         devfs_rules_cleanup(fmp);
  194         fmp->dm_mount = NULL;
  195         hold = --fmp->dm_holdcnt;
  196         mp->mnt_data = NULL;
  197         idx = fmp->dm_idx;
  198         sx_xunlock(&fmp->dm_lock);
  199         free_unr(devfs_unr, idx);
  200         if (hold == 0)
  201                 devfs_unmount_final(fmp);
  202         return 0;
  203 }
  204 
  205 /* Return locked reference to root.  */
  206 
  207 static int
  208 devfs_root(struct mount *mp, int flags, struct vnode **vpp)
  209 {
  210         int error;
  211         struct vnode *vp;
  212         struct devfs_mount *dmp;
  213 
  214         dmp = VFSTODEVFS(mp);
  215         sx_xlock(&dmp->dm_lock);
  216         error = devfs_allocv(dmp->dm_rootdir, mp, LK_EXCLUSIVE, &vp);
  217         if (error)
  218                 return (error);
  219         vp->v_vflag |= VV_ROOT;
  220         *vpp = vp;
  221         return (0);
  222 }
  223 
  224 static int
  225 devfs_statfs(struct mount *mp, struct statfs *sbp)
  226 {
  227 
  228         sbp->f_flags = 0;
  229         sbp->f_bsize = DEV_BSIZE;
  230         sbp->f_iosize = DEV_BSIZE;
  231         sbp->f_blocks = 2;              /* 1K to keep df happy */
  232         sbp->f_bfree = 0;
  233         sbp->f_bavail = 0;
  234         sbp->f_files = 0;
  235         sbp->f_ffree = 0;
  236         return (0);
  237 }
  238 
  239 static struct vfsops devfs_vfsops = {
  240         .vfs_mount =            devfs_mount,
  241         .vfs_root =             devfs_root,
  242         .vfs_statfs =           devfs_statfs,
  243         .vfs_unmount =          devfs_unmount,
  244 };
  245 
  246 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC | VFCF_JAIL);

Cache object: 5aaded41e954913a2e6207a9df29c3f6


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