1 /* $NetBSD: fdesc_vfsops.c,v 1.88 2014/03/23 15:21:16 hannken 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 1.88 2014/03/23 15:21:16 hannken 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 = FDESC_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); 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 .vfs_name = MOUNT_FDESC, 186 .vfs_min_mount_data = 0, 187 .vfs_mount = fdesc_mount, 188 .vfs_start = fdesc_start, 189 .vfs_unmount = fdesc_unmount, 190 .vfs_root = fdesc_root, 191 .vfs_quotactl = (void *)eopnotsupp, 192 .vfs_statvfs = genfs_statvfs, 193 .vfs_sync = fdesc_sync, 194 .vfs_vget = fdesc_vget, 195 .vfs_fhtovp = (void *)eopnotsupp, 196 .vfs_vptofh = (void *)eopnotsupp, 197 .vfs_init = fdesc_init, 198 .vfs_done = fdesc_done, 199 .vfs_snapshot = (void *)eopnotsupp, 200 .vfs_extattrctl = vfs_stdextattrctl, 201 .vfs_suspendctl = (void *)eopnotsupp, 202 .vfs_renamelock_enter = genfs_renamelock_enter, 203 .vfs_renamelock_exit = genfs_renamelock_exit, 204 .vfs_fsync = (void *)eopnotsupp, 205 .vfs_opv_descs = fdesc_vnodeopv_descs 206 }; 207 208 static int 209 fdesc_modcmd(modcmd_t cmd, void *arg) 210 { 211 int error; 212 213 switch (cmd) { 214 case MODULE_CMD_INIT: 215 error = vfs_attach(&fdesc_vfsops); 216 if (error != 0) 217 break; 218 sysctl_createv(&fdesc_sysctl_log, 0, NULL, NULL, 219 CTLFLAG_PERMANENT, 220 CTLTYPE_NODE, "fdesc", 221 SYSCTL_DESCR("File-descriptor file system"), 222 NULL, 0, NULL, 0, 223 CTL_VFS, 7, CTL_EOL); 224 /* 225 * XXX the "7" above could be dynamic, thereby eliminating one 226 * more instance of the "number to vfs" mapping problem, but 227 * "7" is the order as taken from sys/mount.h 228 */ 229 break; 230 case MODULE_CMD_FINI: 231 error = vfs_detach(&fdesc_vfsops); 232 if (error != 0) 233 break; 234 sysctl_teardown(&fdesc_sysctl_log); 235 break; 236 default: 237 error = ENOTTY; 238 break; 239 } 240 241 return (error); 242 } 243