fdesc_vfsops.c revision 1.79
1 /* $NetBSD: fdesc_vfsops.c,v 1.79 2009/03/14 15:36:22 dsl 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 1.79 2009/03/14 15:36:22 dsl 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 fdescmount *fmp; 83 struct vnode *rvp; 84 85 if (mp->mnt_flag & MNT_GETARGS) { 86 *data_len = 0; 87 return 0; 88 } 89 /* 90 * Update is a no-op 91 */ 92 if (mp->mnt_flag & MNT_UPDATE) 93 return (EOPNOTSUPP); 94 95 error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp); 96 if (error) 97 return (error); 98 99 fmp = (struct fdescmount *)malloc(sizeof(struct fdescmount), 100 M_UFSMNT, M_WAITOK); /* XXX */ 101 rvp->v_type = VDIR; 102 rvp->v_vflag |= VV_ROOT; 103 fmp->f_root = rvp; 104 mp->mnt_stat.f_namemax = MAXNAMLEN; 105 mp->mnt_flag |= MNT_LOCAL; 106 mp->mnt_data = fmp; 107 vfs_getnewfsid(mp); 108 109 error = set_statvfs_info(path, UIO_USERSPACE, "fdesc", UIO_SYSSPACE, 110 mp->mnt_op->vfs_name, mp, l); 111 VOP_UNLOCK(rvp, 0); 112 return error; 113 } 114 115 int 116 fdesc_start(struct mount *mp, int flags) 117 { 118 return (0); 119 } 120 121 int 122 fdesc_unmount(struct mount *mp, int mntflags) 123 { 124 int error; 125 int flags = 0; 126 struct vnode *rtvp = VFSTOFDESC(mp)->f_root; 127 128 if (mntflags & MNT_FORCE) 129 flags |= FORCECLOSE; 130 131 if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 132 return (EBUSY); 133 if ((error = vflush(mp, rtvp, flags)) != 0) 134 return (error); 135 136 /* 137 * Blow it away for future re-use 138 */ 139 vgone(rtvp); 140 /* 141 * Finally, throw away the fdescmount structure 142 */ 143 free(mp->mnt_data, M_UFSMNT); /* XXX */ 144 mp->mnt_data = NULL; 145 146 return (0); 147 } 148 149 int 150 fdesc_root(struct mount *mp, struct vnode **vpp) 151 { 152 struct vnode *vp; 153 154 /* 155 * Return locked reference to root. 156 */ 157 vp = VFSTOFDESC(mp)->f_root; 158 VREF(vp); 159 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 160 *vpp = vp; 161 return (0); 162 } 163 164 int 165 fdesc_statvfs(struct mount *mp, struct statvfs *sbp) 166 { 167 struct lwp *l = curlwp; 168 struct filedesc *fdp; 169 struct proc *p; 170 int lim; 171 int i; 172 int last; 173 int freefd; 174 175 /* 176 * Compute number of free file descriptors. 177 * [ Strange results will ensue if the open file 178 * limit is ever reduced below the current number 179 * of open files... ] 180 */ 181 p = l->l_proc; 182 lim = p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 183 fdp = p->p_fd; 184 last = min(fdp->fd_nfiles, lim); 185 freefd = 0; 186 for (i = fdp->fd_freefile; i < last; i++) 187 if (fdp->fd_ofiles[i] == NULL) 188 freefd++; 189 190 /* 191 * Adjust for the fact that the fdesc array may not 192 * have been fully allocated yet. 193 */ 194 if (fdp->fd_nfiles < lim) 195 freefd += (lim - fdp->fd_nfiles); 196 197 sbp->f_bsize = DEV_BSIZE; 198 sbp->f_frsize = DEV_BSIZE; 199 sbp->f_iosize = DEV_BSIZE; 200 sbp->f_blocks = 2; /* 1K to keep df happy */ 201 sbp->f_bfree = 0; 202 sbp->f_bavail = 0; 203 sbp->f_bresvd = 0; 204 sbp->f_files = lim + 1; /* Allow for "." */ 205 sbp->f_ffree = freefd; /* See comments above */ 206 sbp->f_favail = freefd; /* See comments above */ 207 sbp->f_fresvd = 0; 208 copy_statvfs_info(sbp, mp); 209 return (0); 210 } 211 212 /*ARGSUSED*/ 213 int 214 fdesc_sync(struct mount *mp, int waitfor, 215 kauth_cred_t uc) 216 { 217 218 return (0); 219 } 220 221 /* 222 * Fdesc flat namespace lookup. 223 * Currently unsupported. 224 */ 225 int 226 fdesc_vget(struct mount *mp, ino_t ino, 227 struct vnode **vpp) 228 { 229 230 return (EOPNOTSUPP); 231 } 232 233 extern const struct vnodeopv_desc fdesc_vnodeop_opv_desc; 234 235 const struct vnodeopv_desc * const fdesc_vnodeopv_descs[] = { 236 &fdesc_vnodeop_opv_desc, 237 NULL, 238 }; 239 240 struct vfsops fdesc_vfsops = { 241 MOUNT_FDESC, 242 0, 243 fdesc_mount, 244 fdesc_start, 245 fdesc_unmount, 246 fdesc_root, 247 (void *)eopnotsupp, /* vfs_quotactl */ 248 fdesc_statvfs, 249 fdesc_sync, 250 fdesc_vget, 251 (void *)eopnotsupp, /* vfs_fhtovp */ 252 (void *)eopnotsupp, /* vfs_vptofh */ 253 fdesc_init, 254 NULL, 255 fdesc_done, 256 NULL, /* vfs_mountroot */ 257 (int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp, 258 vfs_stdextattrctl, 259 (void *)eopnotsupp, /* vfs_suspendctl */ 260 genfs_renamelock_enter, 261 genfs_renamelock_exit, 262 (void *)eopnotsupp, 263 fdesc_vnodeopv_descs, 264 0, 265 { NULL, NULL}, 266 }; 267 268 static int 269 fdesc_modcmd(modcmd_t cmd, void *arg) 270 { 271 int error; 272 273 switch (cmd) { 274 case MODULE_CMD_INIT: 275 error = vfs_attach(&fdesc_vfsops); 276 if (error != 0) 277 break; 278 sysctl_createv(&fdesc_sysctl_log, 0, NULL, NULL, 279 CTLFLAG_PERMANENT, 280 CTLTYPE_NODE, "vfs", NULL, 281 NULL, 0, NULL, 0, 282 CTL_VFS, CTL_EOL); 283 sysctl_createv(&fdesc_sysctl_log, 0, NULL, NULL, 284 CTLFLAG_PERMANENT, 285 CTLTYPE_NODE, "fdesc", 286 SYSCTL_DESCR("File-descriptor file system"), 287 NULL, 0, NULL, 0, 288 CTL_VFS, 7, CTL_EOL); 289 /* 290 * XXX the "7" above could be dynamic, thereby eliminating one 291 * more instance of the "number to vfs" mapping problem, but 292 * "7" is the order as taken from sys/mount.h 293 */ 294 break; 295 case MODULE_CMD_FINI: 296 error = vfs_detach(&fdesc_vfsops); 297 if (error != 0) 298 break; 299 sysctl_teardown(&fdesc_sysctl_log); 300 break; 301 default: 302 error = ENOTTY; 303 break; 304 } 305 306 return (error); 307 } 308
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