sys/miscfs/fdesc/fdesc_vfsops.c

   1 /*      $NetBSD: fdesc_vfsops.c,v 1.83 2009/11/30 10:59:20 pooka Exp $  */
   2
   3 /*
   4  * Copyright (c) 1992, 1993, 1995
   5  *      The Regents of the University of California.  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. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)fdesc_vfsops.c      8.10 (Berkeley) 5/14/95
  35  *
  36  * #Id: fdesc_vfsops.c,v 1.9 1993/04/06 15:28:33 jsp Exp #
  37  */
  38
  39 /*
  40  * /dev/fd Filesystem
  41  */
  42
  43 #include <sys/cdefs.h>
  44 __KERNEL_RCSID(0, "$NetBSD: fdesc_vfsops.c,v 1.83 2009/11/30 10:59:20 pooka Exp $");
  45
  46 #if defined(_KERNEL_OPT)
  47 #include "opt_compat_netbsd.h"
  48 #endif
  49
  50 #include <sys/param.h>
  51 #include <sys/systm.h>
  52 #include <sys/sysctl.h>
  53 #include <sys/time.h>
  54 #include <sys/proc.h>
  55 #include <sys/resourcevar.h>
  56 #include <sys/filedesc.h>
  57 #include <sys/vnode.h>
  58 #include <sys/mount.h>
  59 #include <sys/dirent.h>
  60 #include <sys/namei.h>
  61 #include <sys/malloc.h>
  62 #include <sys/kauth.h>
  63 #include <sys/module.h>
  64
  65 #include <miscfs/genfs/genfs.h>
  66 #include <miscfs/fdesc/fdesc.h>
  67
  68 MODULE(MODULE_CLASS_VFS, fdesc, NULL);
  69
  70 VFS_PROTOS(fdesc);
  71
  72 static struct sysctllog *fdesc_sysctl_log;
  73
  74 /*
  75  * Mount the per-process file descriptors (/dev/fd)
  76  */
  77 int
  78 fdesc_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
  79 {
  80         struct lwp *l = curlwp;
  81         int error = 0;
  82         struct vnode *rvp;
  83
  84         if (mp->mnt_flag & MNT_GETARGS) {
  85                 *data_len = 0;
  86                 return 0;
  87         }
  88         /*
  89          * Update is a no-op
  90          */
  91         if (mp->mnt_flag & MNT_UPDATE)
  92                 return (EOPNOTSUPP);
  93
  94         error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp);
  95         if (error)
  96                 return (error);
  97
  98         rvp->v_type = VDIR;
  99         rvp->v_vflag |= VV_ROOT;
 100         mp->mnt_stat.f_namemax = MAXNAMLEN;
 101         mp->mnt_flag |= MNT_LOCAL;
 102         mp->mnt_data = rvp;
 103         vfs_getnewfsid(mp);
 104
 105         error = set_statvfs_info(path, UIO_USERSPACE, "fdesc", UIO_SYSSPACE,
 106             mp->mnt_op->vfs_name, mp, l);
 107         VOP_UNLOCK(rvp, 0);
 108         return error;
 109 }
 110
 111 int
 112 fdesc_start(struct mount *mp, int flags)
 113 {
 114         return (0);
 115 }
 116
 117 int
 118 fdesc_unmount(struct mount *mp, int mntflags)
 119 {
 120         int error;
 121         int flags = 0;
 122         struct vnode *rtvp = mp->mnt_data;
 123
 124         if (mntflags & MNT_FORCE)
 125                 flags |= FORCECLOSE;
 126
 127         if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
 128                 return (EBUSY);
 129         if ((error = vflush(mp, rtvp, flags)) != 0)
 130                 return (error);
 131
 132         /*
 133          * Blow it away for future re-use
 134          */
 135         vgone(rtvp);
 136         mp->mnt_data = NULL;
 137
 138         return (0);
 139 }
 140
 141 int
 142 fdesc_root(struct mount *mp, struct vnode **vpp)
 143 {
 144         struct vnode *vp;
 145
 146         /*
 147          * Return locked reference to root.
 148          */
 149         vp = mp->mnt_data;
 150         vref(vp);
 151         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 152         *vpp = vp;
 153         return (0);
 154 }
 155
 156 /*ARGSUSED*/
 157 int
 158 fdesc_sync(struct mount *mp, int waitfor,
 159     kauth_cred_t uc)
 160 {
 161
 162         return (0);
 163 }
 164
 165 /*
 166  * Fdesc flat namespace lookup.
 167  * Currently unsupported.
 168  */
 169 int
 170 fdesc_vget(struct mount *mp, ino_t ino,
 171     struct vnode **vpp)
 172 {
 173
 174         return (EOPNOTSUPP);
 175 }
 176
 177 extern const struct vnodeopv_desc fdesc_vnodeop_opv_desc;
 178
 179 const struct vnodeopv_desc * const fdesc_vnodeopv_descs[] = {
 180         &fdesc_vnodeop_opv_desc,
 181         NULL,
 182 };
 183
 184 struct vfsops fdesc_vfsops = {
 185         MOUNT_FDESC,
 186         0,
 187         fdesc_mount,
 188         fdesc_start,
 189         fdesc_unmount,
 190         fdesc_root,
 191         (void *)eopnotsupp,             /* vfs_quotactl */
 192         genfs_statvfs,
 193         fdesc_sync,
 194         fdesc_vget,
 195         (void *)eopnotsupp,             /* vfs_fhtovp */
 196         (void *)eopnotsupp,             /* vfs_vptofh */
 197         fdesc_init,
 198         NULL,
 199         fdesc_done,
 200         NULL,                           /* vfs_mountroot */
 201         (int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
 202         vfs_stdextattrctl,
 203         (void *)eopnotsupp,             /* vfs_suspendctl */
 204         genfs_renamelock_enter,
 205         genfs_renamelock_exit,
 206         (void *)eopnotsupp,
 207         fdesc_vnodeopv_descs,
 208         0,
 209         { NULL, NULL},
 210 };
 211
 212 static int
 213 fdesc_modcmd(modcmd_t cmd, void *arg)
 214 {
 215         int error;
 216
 217         switch (cmd) {
 218         case MODULE_CMD_INIT:
 219                 error = vfs_attach(&fdesc_vfsops);
 220                 if (error != 0)
 221                         break;
 222                 sysctl_createv(&fdesc_sysctl_log, 0, NULL, NULL,
 223                                CTLFLAG_PERMANENT,
 224                                CTLTYPE_NODE, "vfs", NULL,
 225                                NULL, 0, NULL, 0,
 226                                CTL_VFS, CTL_EOL);
 227                 sysctl_createv(&fdesc_sysctl_log, 0, NULL, NULL,
 228                                CTLFLAG_PERMANENT,
 229                                CTLTYPE_NODE, "fdesc",
 230                                SYSCTL_DESCR("File-descriptor file system"),
 231                                NULL, 0, NULL, 0,
 232                                CTL_VFS, 7, CTL_EOL);
 233                 /*
 234                  * XXX the "7" above could be dynamic, thereby eliminating one
 235                  * more instance of the "number to vfs" mapping problem, but
 236                  * "7" is the order as taken from sys/mount.h
 237                  */
 238                 break;
 239         case MODULE_CMD_FINI:
 240                 error = vfs_detach(&fdesc_vfsops);
 241                 if (error != 0)
 242                         break;
 243                 sysctl_teardown(&fdesc_sysctl_log);
 244                 break;
 245         default:
 246                 error = ENOTTY;
 247                 break;
 248         }
 249
 250         return (error);
 251 }