fdesc_vfsops.c revision 1.94
1 /* $NetBSD: fdesc_vfsops.c,v 1.94 2020/03/16 21:20:11 pgoyette 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 1.94 2020/03/16 21:20:11 pgoyette 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 static struct sysctllog *fdesc_sysctl_log; 72 73 /* 74 * Mount the per-process file descriptors (/dev/fd) 75 */ 76 int 77 fdesc_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 78 { 79 struct lwp *l = curlwp; 80 int error = 0, ix; 81 struct vnode *rvp; 82 83 if (mp->mnt_flag & MNT_GETARGS) { 84 *data_len = 0; 85 return 0; 86 } 87 /* 88 * Update is a no-op 89 */ 90 if (mp->mnt_flag & MNT_UPDATE) 91 return (EOPNOTSUPP); 92 93 ix = FD_ROOT; 94 error = vcache_get(mp, &ix, sizeof(ix), &rvp); 95 if (error) 96 return error; 97 98 mp->mnt_stat.f_namemax = FDESC_MAXNAMLEN; 99 mp->mnt_flag |= MNT_LOCAL; 100 mp->mnt_data = rvp; 101 vfs_getnewfsid(mp); 102 103 error = set_statvfs_info(path, UIO_USERSPACE, "fdesc", UIO_SYSSPACE, 104 mp->mnt_op->vfs_name, mp, l); 105 return error; 106 } 107 108 int 109 fdesc_start(struct mount *mp, int flags) 110 { 111 return (0); 112 } 113 114 int 115 fdesc_unmount(struct mount *mp, int mntflags) 116 { 117 int error; 118 int flags = 0; 119 struct vnode *rtvp = mp->mnt_data; 120 121 if (mntflags & MNT_FORCE) 122 flags |= FORCECLOSE; 123 124 if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 125 return (EBUSY); 126 if ((error = vflush(mp, rtvp, flags)) != 0) 127 return (error); 128 129 /* 130 * Blow it away for future re-use 131 */ 132 vgone(rtvp); 133 mp->mnt_data = NULL; 134 135 return (0); 136 } 137 138 int 139 fdesc_root(struct mount *mp, int lktype, struct vnode **vpp) 140 { 141 struct vnode *vp; 142 143 /* 144 * Return locked reference to root. 145 */ 146 vp = mp->mnt_data; 147 vref(vp); 148 vn_lock(vp, lktype | LK_RETRY); 149 *vpp = vp; 150 return (0); 151 } 152 153 /*ARGSUSED*/ 154 int 155 fdesc_sync(struct mount *mp, int waitfor, 156 kauth_cred_t uc) 157 { 158 159 return (0); 160 } 161 162 /* 163 * Fdesc flat namespace lookup. 164 * Currently unsupported. 165 */ 166 int 167 fdesc_vget(struct mount *mp, ino_t ino, int lktype, 168 struct vnode **vpp) 169 { 170 171 return (EOPNOTSUPP); 172 } 173 174 int 175 fdesc_loadvnode(struct mount *mp, struct vnode *vp, 176 const void *key, size_t key_len, const void **new_key) 177 { 178 int ix; 179 struct fdescnode *fd; 180 181 KASSERT(key_len == sizeof(ix)); 182 memcpy(&ix, key, key_len); 183 184 fd = kmem_alloc(sizeof(struct fdescnode), KM_SLEEP); 185 fd->fd_fd = -1; 186 fd->fd_link = NULL; 187 fd->fd_ix = ix; 188 fd->fd_vnode = vp; 189 vp->v_tag = VT_FDESC; 190 vp->v_op = fdesc_vnodeop_p; 191 vp->v_data = fd; 192 switch (ix) { 193 case FD_ROOT: 194 fd->fd_type = Froot; 195 vp->v_type = VDIR; 196 vp->v_vflag |= VV_ROOT; 197 break; 198 case FD_DEVFD: 199 fd->fd_type = Fdevfd; 200 vp->v_type = VDIR; 201 break; 202 case FD_CTTY: 203 fd->fd_type = Fctty; 204 vp->v_type = VCHR; 205 break; 206 case FD_STDIN: 207 fd->fd_type = Flink; 208 fd->fd_link = "fd/0"; 209 vp->v_type = VLNK; 210 break; 211 case FD_STDOUT: 212 fd->fd_type = Flink; 213 fd->fd_link = "fd/1"; 214 vp->v_type = VLNK; 215 break; 216 case FD_STDERR: 217 fd->fd_type = Flink; 218 fd->fd_link = "fd/2"; 219 vp->v_type = VLNK; 220 break; 221 default: 222 KASSERT(ix >= FD_DESC); 223 fd->fd_type = Fdesc; 224 fd->fd_fd = ix - FD_DESC; 225 vp->v_type = VNON; 226 break; 227 } 228 uvm_vnp_setsize(vp, 0); 229 *new_key = &fd->fd_ix; 230 231 return 0; 232 } 233 234 extern const struct vnodeopv_desc fdesc_vnodeop_opv_desc; 235 236 const struct vnodeopv_desc * const fdesc_vnodeopv_descs[] = { 237 &fdesc_vnodeop_opv_desc, 238 NULL, 239 }; 240 241 struct vfsops fdesc_vfsops = { 242 .vfs_name = MOUNT_FDESC, 243 .vfs_min_mount_data = 0, 244 .vfs_mount = fdesc_mount, 245 .vfs_start = fdesc_start, 246 .vfs_unmount = fdesc_unmount, 247 .vfs_root = fdesc_root, 248 .vfs_quotactl = (void *)eopnotsupp, 249 .vfs_statvfs = genfs_statvfs, 250 .vfs_sync = fdesc_sync, 251 .vfs_vget = fdesc_vget, 252 .vfs_loadvnode = fdesc_loadvnode, 253 .vfs_fhtovp = (void *)eopnotsupp, 254 .vfs_vptofh = (void *)eopnotsupp, 255 .vfs_init = fdesc_init, 256 .vfs_done = fdesc_done, 257 .vfs_snapshot = (void *)eopnotsupp, 258 .vfs_extattrctl = vfs_stdextattrctl, 259 .vfs_suspendctl = genfs_suspendctl, 260 .vfs_renamelock_enter = genfs_renamelock_enter, 261 .vfs_renamelock_exit = genfs_renamelock_exit, 262 .vfs_fsync = (void *)eopnotsupp, 263 .vfs_opv_descs = fdesc_vnodeopv_descs 264 }; 265 266 SYSCTL_SETUP(fdesc_sysctl_setup, "fdesc sysctl") 267 { 268 269 sysctl_createv(&fdesc_sysctl_log, 0, NULL, NULL, 270 CTLFLAG_PERMANENT, 271 CTLTYPE_NODE, "fdesc", 272 SYSCTL_DESCR("File-descriptor file system"), 273 NULL, 0, NULL, 0, 274 CTL_VFS, 7, CTL_EOL); 275 /* 276 * XXX the "7" above could be dynamic, thereby eliminating one 277 * more instance of the "number to vfs" mapping problem, but 278 * "7" is the order as taken from sys/mount.h 279 */ 280 } 281 282 static int 283 fdesc_modcmd(modcmd_t cmd, void *arg) 284 { 285 int error; 286 287 switch (cmd) { 288 case MODULE_CMD_INIT: 289 error = vfs_attach(&fdesc_vfsops); 290 if (error != 0) 291 break; 292 break; 293 case MODULE_CMD_FINI: 294 error = vfs_detach(&fdesc_vfsops); 295 if (error != 0) 296 break; 297 break; 298 default: 299 error = ENOTTY; 300 break; 301 } 302 303 return (error); 304 } 305
Indexes created Fri Sep 26 08:10:20 GMT 2025