sys/vfs/fdesc/fdesc_vfsops.c

   1 /*
   2  * Copyright (c) 1992, 1993, 1995
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software donated to Berkeley by
   6  * Jan-Simon Pendry.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  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 REGENTS 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 REGENTS 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  *      @(#)fdesc_vfsops.c      8.4 (Berkeley) 1/21/94
  37  *
  38  * $FreeBSD: src/sys/miscfs/fdesc/fdesc_vfsops.c,v 1.22.2.3 2002/08/23 17:42:39 njl Exp $
  39  * $DragonFly: src/sys/vfs/fdesc/fdesc_vfsops.c,v 1.22 2006/09/05 00:55:50 dillon Exp $
  40  */
  41
  42 /*
  43  * /dev/fd Filesystem
  44  */
  45
  46 #include <sys/param.h>
  47 #include <sys/systm.h>
  48 #include <sys/filedesc.h>
  49 #include <sys/kernel.h>
  50 #include <sys/lock.h>
  51 #include <sys/malloc.h>
  52 #include <sys/mount.h>
  53 #include <sys/proc.h>
  54 #include <sys/resourcevar.h>
  55 #include <sys/socket.h>
  56 #include <sys/vnode.h>
  57
  58 #include "fdesc.h"
  59
  60 extern struct vop_ops fdesc_vnode_vops;
  61
  62 static MALLOC_DEFINE(M_FDESCMNT, "FDESC mount", "FDESC mount structure");
  63
  64 static int      fdesc_mount (struct mount *mp, char *path, caddr_t data,
  65                                 struct ucred *cred);
  66 static int      fdesc_unmount (struct mount *mp, int mntflags);
  67 static int      fdesc_statfs (struct mount *mp, struct statfs *sbp,
  68                                 struct ucred *cred);
  69
  70 /*
  71  * Mount the per-process file descriptors (/dev/fd)
  72  */
  73 static int
  74 fdesc_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
  75 {
  76         int error = 0;
  77         struct fdescmount *fmp;
  78         struct vnode *rvp;
  79
  80         if (path == NULL)
  81                 panic("fdesc_mount: cannot mount as root");
  82
  83         /*
  84          * Update is a no-op
  85          */
  86         if (mp->mnt_flag & MNT_UPDATE)
  87                 return (EOPNOTSUPP);
  88
  89         vfs_add_vnodeops(mp, &fdesc_vnode_vops, &mp->mnt_vn_norm_ops);
  90
  91         error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp);
  92         if (error)
  93                 return (error);
  94
  95         MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount),
  96                                 M_FDESCMNT, M_WAITOK);  /* XXX */
  97         rvp->v_type = VDIR;
  98         rvp->v_flag |= VROOT;
  99         fmp->f_root = rvp;
 100         /* XXX -- don't mark as local to work around fts() problems */
 101         /*mp->mnt_flag |= MNT_LOCAL;*/
 102         mp->mnt_data = (qaddr_t) fmp;
 103         vfs_getnewfsid(mp);
 104
 105         bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
 106         bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc"));
 107         fdesc_statfs(mp, &mp->mnt_stat, cred);
 108         return (0);
 109 }
 110
 111 static int
 112 fdesc_unmount(struct mount *mp, int mntflags)
 113 {
 114         int error;
 115         int flags = 0;
 116
 117         if (mntflags & MNT_FORCE)
 118                 flags |= FORCECLOSE;
 119
 120         /*
 121          * Clear out buffer cache.  I don't think we
 122          * ever get anything cached at this level at the
 123          * moment, but who knows...
 124          *
 125          * There is 1 extra root vnode reference corresponding
 126          * to f_root.
 127          */
 128         if ((error = vflush(mp, 1, flags)) != 0)
 129                 return (error);
 130
 131         /*
 132          * Finally, throw away the fdescmount structure
 133          */
 134         kfree(mp->mnt_data, M_FDESCMNT);        /* XXX */
 135         mp->mnt_data = 0;
 136
 137         return (0);
 138 }
 139
 140 int
 141 fdesc_root(struct mount *mp, struct vnode **vpp)
 142 {
 143         struct vnode *vp;
 144         int error;
 145
 146         /*
 147          * Return locked reference to root.
 148          */
 149         vp = VFSTOFDESC(mp)->f_root;
 150         error = vget(vp, LK_EXCLUSIVE | LK_RETRY);
 151         if (error == 0)
 152                 *vpp = vp;
 153         return (error);
 154 }
 155
 156 static int
 157 fdesc_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
 158 {
 159         sbp->f_flags = 0;
 160         sbp->f_bsize = DEV_BSIZE;
 161         sbp->f_iosize = DEV_BSIZE;
 162         sbp->f_blocks = 2;              /* 1K to keep df happy */
 163         sbp->f_bfree = 0;
 164         sbp->f_bavail = 0;
 165         sbp->f_files = 0;               /* dummy up these fields */
 166         sbp->f_ffree = 0;
 167         if (sbp != &mp->mnt_stat) {
 168                 sbp->f_type = mp->mnt_vfc->vfc_typenum;
 169                 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
 170                 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
 171         }
 172         return (0);
 173 }
 174
 175 static struct vfsops fdesc_vfsops = {
 176         .vfs_mount =            fdesc_mount,
 177         .vfs_unmount =          fdesc_unmount,
 178         .vfs_root =             fdesc_root,
 179         .vfs_statfs =           fdesc_statfs,
 180         .vfs_sync =             vfs_stdsync,
 181         .vfs_init =             fdesc_init,
 182         .vfs_uninit =           fdesc_uninit
 183 };
 184
 185 VFS_SET(fdesc_vfsops, fdesc, VFCF_SYNTHETIC);