1 /* $NetBSD: fdesc_vfsops.c,v 1.89 2014/07/13 11:23:01 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 1.89 2014/07/13 11:23:01 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, ix; 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 ix = FD_ROOT; 95 error = vcache_get(mp, &ix, sizeof(ix), &rvp); 96 if (error) 97 return error; 98 99 mp->mnt_stat.f_namemax = FDESC_MAXNAMLEN; 100 mp->mnt_flag |= MNT_LOCAL; 101 mp->mnt_data = rvp; 102 vfs_getnewfsid(mp); 103 104 error = set_statvfs_info(path, UIO_USERSPACE, "fdesc", UIO_SYSSPACE, 105 mp->mnt_op->vfs_name, mp, l); 106 return error; 107 } 108 109 int 110 fdesc_start(struct mount *mp, int flags) 111 { 112 return (0); 113 } 114 115 int 116 fdesc_unmount(struct mount *mp, int mntflags) 117 { 118 int error; 119 int flags = 0; 120 struct vnode *rtvp = mp->mnt_data; 121 122 if (mntflags & MNT_FORCE) 123 flags |= FORCECLOSE; 124 125 if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 126 return (EBUSY); 127 if ((error = vflush(mp, rtvp, flags)) != 0) 128 return (error); 129 130 /* 131 * Blow it away for future re-use 132 */ 133 vgone(rtvp); 134 mp->mnt_data = NULL; 135 136 return (0); 137 } 138 139 int 140 fdesc_root(struct mount *mp, struct vnode **vpp) 141 { 142 struct vnode *vp; 143 144 /* 145 * Return locked reference to root. 146 */ 147 vp = mp->mnt_data; 148 vref(vp); 149 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 150 *vpp = vp; 151 return (0); 152 } 153 154 /*ARGSUSED*/ 155 int 156 fdesc_sync(struct mount *mp, int waitfor, 157 kauth_cred_t uc) 158 { 159 160 return (0); 161 } 162 163 /* 164 * Fdesc flat namespace lookup. 165 * Currently unsupported. 166 */ 167 int 168 fdesc_vget(struct mount *mp, ino_t ino, 169 struct vnode **vpp) 170 { 171 172 return (EOPNOTSUPP); 173 } 174 175 int 176 fdesc_loadvnode(struct mount *mp, struct vnode *vp, 177 const void *key, size_t key_len, const void **new_key) 178 { 179 int ix; 180 struct fdescnode *fd; 181 182 KASSERT(key_len == sizeof(ix)); 183 memcpy(&ix, key, key_len); 184 185 fd = kmem_alloc(sizeof(struct fdescnode), KM_SLEEP); 186 fd->fd_fd = -1; 187 fd->fd_link = NULL; 188 fd->fd_ix = ix; 189 fd->fd_vnode = vp; 190 vp->v_tag = VT_FDESC; 191 vp->v_op = fdesc_vnodeop_p; 192 vp->v_data = fd; 193 switch (ix) { 194 case FD_ROOT: 195 fd->fd_type = Froot; 196 vp->v_type = VDIR; 197 vp->v_vflag |= VV_ROOT; 198 break; 199 case FD_DEVFD: 200 fd->fd_type = Fdevfd; 201 vp->v_type = VDIR; 202 break; 203 case FD_CTTY: 204 fd->fd_type = Fctty; 205 vp->v_type = VNON; 206 break; 207 case FD_STDIN: 208 fd->fd_type = Flink; 209 fd->fd_link = "fd/0"; 210 vp->v_type = VLNK; 211 break; 212 case FD_STDOUT: 213 fd->fd_type = Flink; 214 fd->fd_link = "fd/1"; 215 vp->v_type = VLNK; 216 break; 217 case FD_STDERR: 218 fd->fd_type = Flink; 219 fd->fd_link = "fd/2"; 220 vp->v_type = VLNK; 221 break; 222 default: 223 KASSERT(ix >= FD_DESC); 224 fd->fd_type = Fdesc; 225 fd->fd_fd = ix - FD_DESC; 226 vp->v_type = VNON; 227 break; 228 } 229 uvm_vnp_setsize(vp, 0); 230 *new_key = &fd->fd_ix; 231 232 return 0; 233 } 234 235 extern const struct vnodeopv_desc fdesc_vnodeop_opv_desc; 236 237 const struct vnodeopv_desc * const fdesc_vnodeopv_descs[] = { 238 &fdesc_vnodeop_opv_desc, 239 NULL, 240 }; 241 242 struct vfsops fdesc_vfsops = { 243 .vfs_name = MOUNT_FDESC, 244 .vfs_min_mount_data = 0, 245 .vfs_mount = fdesc_mount, 246 .vfs_start = fdesc_start, 247 .vfs_unmount = fdesc_unmount, 248 .vfs_root = fdesc_root, 249 .vfs_quotactl = (void *)eopnotsupp, 250 .vfs_statvfs = genfs_statvfs, 251 .vfs_sync = fdesc_sync, 252 .vfs_vget = fdesc_vget, 253 .vfs_loadvnode = fdesc_loadvnode, 254 .vfs_fhtovp = (void *)eopnotsupp, 255 .vfs_vptofh = (void *)eopnotsupp, 256 .vfs_init = fdesc_init, 257 .vfs_done = fdesc_done, 258 .vfs_snapshot = (void *)eopnotsupp, 259 .vfs_extattrctl = vfs_stdextattrctl, 260 .vfs_suspendctl = (void *)eopnotsupp, 261 .vfs_renamelock_enter = genfs_renamelock_enter, 262 .vfs_renamelock_exit = genfs_renamelock_exit, 263 .vfs_fsync = (void *)eopnotsupp, 264 .vfs_opv_descs = fdesc_vnodeopv_descs 265 }; 266 267 static int 268 fdesc_modcmd(modcmd_t cmd, void *arg) 269 { 270 int error; 271 272 switch (cmd) { 273 case MODULE_CMD_INIT: 274 error = vfs_attach(&fdesc_vfsops); 275 if (error != 0) 276 break; 277 sysctl_createv(&fdesc_sysctl_log, 0, NULL, NULL, 278 CTLFLAG_PERMANENT, 279 CTLTYPE_NODE, "fdesc", 280 SYSCTL_DESCR("File-descriptor file system"), 281 NULL, 0, NULL, 0, 282 CTL_VFS, 7, CTL_EOL); 283 /* 284 * XXX the "7" above could be dynamic, thereby eliminating one 285 * more instance of the "number to vfs" mapping problem, but 286 * "7" is the order as taken from sys/mount.h 287 */ 288 break; 289 case MODULE_CMD_FINI: 290 error = vfs_detach(&fdesc_vfsops); 291 if (error != 0) 292 break; 293 sysctl_teardown(&fdesc_sysctl_log); 294 break; 295 default: 296 error = ENOTTY; 297 break; 298 } 299 300 return (error); 301 } 302