1 /* $NetBSD: fdesc_vfsops.c,v 1.96 2020/04/13 19:23:18 ad 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 1.96 2020/04/13 19:23:18 ad 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/kauth.h> 62 #include <sys/module.h> 63 64 #include <miscfs/genfs/genfs.h> 65 #include <miscfs/fdesc/fdesc.h> 66 67 MODULE(MODULE_CLASS_VFS, fdesc, NULL); 68 69 VFS_PROTOS(fdesc); 70 71 /* 72 * Mount the per-process file descriptors (/dev/fd) 73 */ 74 int 75 fdesc_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 76 { 77 struct lwp *l = curlwp; 78 int error = 0, ix; 79 struct vnode *rvp; 80 81 if (mp->mnt_flag & MNT_GETARGS) { 82 *data_len = 0; 83 return 0; 84 } 85 /* 86 * Update is a no-op 87 */ 88 if (mp->mnt_flag & MNT_UPDATE) 89 return (EOPNOTSUPP); 90 91 ix = FD_ROOT; 92 error = vcache_get(mp, &ix, sizeof(ix), &rvp); 93 if (error) 94 return error; 95 96 mp->mnt_stat.f_namemax = FDESC_MAXNAMLEN; 97 mp->mnt_flag |= MNT_LOCAL; 98 mp->mnt_data = rvp; 99 vfs_getnewfsid(mp); 100 101 error = set_statvfs_info(path, UIO_USERSPACE, "fdesc", UIO_SYSSPACE, 102 mp->mnt_op->vfs_name, mp, l); 103 return error; 104 } 105 106 int 107 fdesc_start(struct mount *mp, int flags) 108 { 109 return (0); 110 } 111 112 int 113 fdesc_unmount(struct mount *mp, int mntflags) 114 { 115 int error; 116 int flags = 0; 117 struct vnode *rtvp = mp->mnt_data; 118 119 if (mntflags & MNT_FORCE) 120 flags |= FORCECLOSE; 121 122 if (vrefcnt(rtvp) > 1 && (mntflags & MNT_FORCE) == 0) 123 return (EBUSY); 124 if ((error = vflush(mp, rtvp, flags)) != 0) 125 return (error); 126 127 /* 128 * Blow it away for future re-use 129 */ 130 vgone(rtvp); 131 mp->mnt_data = NULL; 132 133 return (0); 134 } 135 136 int 137 fdesc_root(struct mount *mp, int lktype, struct vnode **vpp) 138 { 139 struct vnode *vp; 140 141 /* 142 * Return locked reference to root. 143 */ 144 vp = mp->mnt_data; 145 vref(vp); 146 vn_lock(vp, lktype | LK_RETRY); 147 *vpp = vp; 148 return (0); 149 } 150 151 /*ARGSUSED*/ 152 int 153 fdesc_sync(struct mount *mp, int waitfor, 154 kauth_cred_t uc) 155 { 156 157 return (0); 158 } 159 160 /* 161 * Fdesc flat namespace lookup. 162 * Currently unsupported. 163 */ 164 int 165 fdesc_vget(struct mount *mp, ino_t ino, int lktype, 166 struct vnode **vpp) 167 { 168 169 return (EOPNOTSUPP); 170 } 171 172 int 173 fdesc_loadvnode(struct mount *mp, struct vnode *vp, 174 const void *key, size_t key_len, const void **new_key) 175 { 176 int ix; 177 struct fdescnode *fd; 178 179 KASSERT(key_len == sizeof(ix)); 180 memcpy(&ix, key, key_len); 181 182 fd = kmem_alloc(sizeof(struct fdescnode), KM_SLEEP); 183 fd->fd_fd = -1; 184 fd->fd_link = NULL; 185 fd->fd_ix = ix; 186 fd->fd_vnode = vp; 187 vp->v_tag = VT_FDESC; 188 vp->v_op = fdesc_vnodeop_p; 189 vp->v_data = fd; 190 switch (ix) { 191 case FD_ROOT: 192 fd->fd_type = Froot; 193 vp->v_type = VDIR; 194 vp->v_vflag |= VV_ROOT; 195 break; 196 case FD_DEVFD: 197 fd->fd_type = Fdevfd; 198 vp->v_type = VDIR; 199 break; 200 case FD_CTTY: 201 fd->fd_type = Fctty; 202 vp->v_type = VCHR; 203 break; 204 case FD_STDIN: 205 fd->fd_type = Flink; 206 fd->fd_link = "fd/0"; 207 vp->v_type = VLNK; 208 break; 209 case FD_STDOUT: 210 fd->fd_type = Flink; 211 fd->fd_link = "fd/1"; 212 vp->v_type = VLNK; 213 break; 214 case FD_STDERR: 215 fd->fd_type = Flink; 216 fd->fd_link = "fd/2"; 217 vp->v_type = VLNK; 218 break; 219 default: 220 KASSERT(ix >= FD_DESC); 221 fd->fd_type = Fdesc; 222 fd->fd_fd = ix - FD_DESC; 223 vp->v_type = VNON; 224 break; 225 } 226 uvm_vnp_setsize(vp, 0); 227 *new_key = &fd->fd_ix; 228 229 return 0; 230 } 231 232 extern const struct vnodeopv_desc fdesc_vnodeop_opv_desc; 233 234 const struct vnodeopv_desc * const fdesc_vnodeopv_descs[] = { 235 &fdesc_vnodeop_opv_desc, 236 NULL, 237 }; 238 239 struct vfsops fdesc_vfsops = { 240 .vfs_name = MOUNT_FDESC, 241 .vfs_min_mount_data = 0, 242 .vfs_mount = fdesc_mount, 243 .vfs_start = fdesc_start, 244 .vfs_unmount = fdesc_unmount, 245 .vfs_root = fdesc_root, 246 .vfs_quotactl = (void *)eopnotsupp, 247 .vfs_statvfs = genfs_statvfs, 248 .vfs_sync = fdesc_sync, 249 .vfs_vget = fdesc_vget, 250 .vfs_loadvnode = fdesc_loadvnode, 251 .vfs_fhtovp = (void *)eopnotsupp, 252 .vfs_vptofh = (void *)eopnotsupp, 253 .vfs_init = fdesc_init, 254 .vfs_done = fdesc_done, 255 .vfs_snapshot = (void *)eopnotsupp, 256 .vfs_extattrctl = vfs_stdextattrctl, 257 .vfs_suspendctl = genfs_suspendctl, 258 .vfs_renamelock_enter = genfs_renamelock_enter, 259 .vfs_renamelock_exit = genfs_renamelock_exit, 260 .vfs_fsync = (void *)eopnotsupp, 261 .vfs_opv_descs = fdesc_vnodeopv_descs 262 }; 263 264 SYSCTL_SETUP(fdesc_sysctl_setup, "fdesc sysctl") 265 { 266 267 sysctl_createv(clog, 0, NULL, NULL, 268 CTLFLAG_PERMANENT, 269 CTLTYPE_NODE, "fdesc", 270 SYSCTL_DESCR("File-descriptor file system"), 271 NULL, 0, NULL, 0, 272 CTL_VFS, 7, CTL_EOL); 273 /* 274 * XXX the "7" above could be dynamic, thereby eliminating one 275 * more instance of the "number to vfs" mapping problem, but 276 * "7" is the order as taken from sys/mount.h 277 */ 278 } 279 280 static int 281 fdesc_modcmd(modcmd_t cmd, void *arg) 282 { 283 int error; 284 285 switch (cmd) { 286 case MODULE_CMD_INIT: 287 error = vfs_attach(&fdesc_vfsops); 288 if (error != 0) 289 break; 290 break; 291 case MODULE_CMD_FINI: 292 error = vfs_detach(&fdesc_vfsops); 293 if (error != 0) 294 break; 295 break; 296 default: 297 error = ENOTTY; 298 break; 299 } 300 301 return (error); 302 } 303
Indexes created Wed Sep 24 05:09:52 GMT 2025