fdesc_vfsops.c revision 89306
1/* 2 * Copyright (c) 1992, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software donated to Berkeley by 6 * Jan-Simon Pendry. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)fdesc_vfsops.c 8.4 (Berkeley) 1/21/94 37 * 38 * $FreeBSD: head/sys/fs/fdescfs/fdesc_vfsops.c 89306 2002-01-13 11:58:06Z alfred $ 39 */ 40 41/* 42 * /dev/fd Filesystem 43 */ 44 45#include <sys/param.h> 46#include <sys/systm.h> 47#include <sys/filedesc.h> 48#include <sys/kernel.h> 49#include <sys/lock.h> 50#include <sys/malloc.h> 51#include <sys/mount.h> 52#include <sys/proc.h> 53#include <sys/resourcevar.h> 54#include <sys/vnode.h> 55 56#include <fs/fdescfs/fdesc.h> 57 58static MALLOC_DEFINE(M_FDESCMNT, "FDESC mount", "FDESC mount structure"); 59 60static int fdesc_mount __P((struct mount *mp, char *path, caddr_t data, 61 struct nameidata *ndp, struct thread *td)); 62static int fdesc_unmount __P((struct mount *mp, int mntflags, 63 struct thread *td)); 64static int fdesc_statfs __P((struct mount *mp, struct statfs *sbp, 65 struct thread *td)); 66 67/* 68 * Mount the per-process file descriptors (/dev/fd) 69 */ 70static int 71fdesc_mount(mp, path, data, ndp, td) 72 struct mount *mp; 73 char *path; 74 caddr_t data; 75 struct nameidata *ndp; 76 struct thread *td; 77{ 78 int error = 0; 79 struct fdescmount *fmp; 80 struct vnode *rvp; 81 82 /* 83 * Update is a no-op 84 */ 85 if (mp->mnt_flag & MNT_UPDATE) 86 return (EOPNOTSUPP); 87 88 error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp, td); 89 if (error) 90 return (error); 91 92 MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount), 93 M_FDESCMNT, M_WAITOK); /* XXX */ 94 rvp->v_type = VDIR; 95 rvp->v_flag |= VROOT; 96 fmp->f_root = rvp; 97 /* XXX -- don't mark as local to work around fts() problems */ 98 /*mp->mnt_flag |= MNT_LOCAL;*/ 99 mp->mnt_data = (qaddr_t) fmp; 100 vfs_getnewfsid(mp); 101 102 bzero(mp->mnt_stat.f_mntfromname, MNAMELEN); 103 bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc")); 104 (void)fdesc_statfs(mp, &mp->mnt_stat, td); 105 return (0); 106} 107 108static int 109fdesc_unmount(mp, mntflags, td) 110 struct mount *mp; 111 int mntflags; 112 struct thread *td; 113{ 114 int error; 115 int flags = 0; 116 117 if (mntflags & MNT_FORCE) 118 flags |= FORCECLOSE; 119 120 /* 121 * Clear out buffer cache. I don't think we 122 * ever get anything cached at this level at the 123 * moment, but who knows... 124 * 125 * There is 1 extra root vnode reference corresponding 126 * to f_root. 127 */ 128 if ((error = vflush(mp, 1, flags)) != 0) 129 return (error); 130 131 /* 132 * Finally, throw away the fdescmount structure 133 */ 134 free(mp->mnt_data, M_FDESCMNT); /* XXX */ 135 mp->mnt_data = 0; 136 137 return (0); 138} 139 140int 141fdesc_root(mp, vpp) 142 struct mount *mp; 143 struct vnode **vpp; 144{ 145 struct thread *td = curthread; /* XXX */ 146 struct vnode *vp; 147 148 /* 149 * Return locked reference to root. 150 */ 151 vp = VFSTOFDESC(mp)->f_root; 152 VREF(vp); 153 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 154 *vpp = vp; 155 return (0); 156} 157 158static int 159fdesc_statfs(mp, sbp, td) 160 struct mount *mp; 161 struct statfs *sbp; 162 struct thread *td; 163{ 164 struct filedesc *fdp; 165 int lim; 166 int i; 167 int last; 168 int freefd; 169 170 /* 171 * Compute number of free file descriptors. 172 * [ Strange results will ensue if the open file 173 * limit is ever reduced below the current number 174 * of open files... ] 175 */ 176 lim = td->td_proc->p_rlimit[RLIMIT_NOFILE].rlim_cur; 177 fdp = td->td_proc->p_fd; 178 FILEDESC_LOCK(fdp); 179 last = min(fdp->fd_nfiles, lim); 180 freefd = 0; 181 for (i = fdp->fd_freefile; i < last; i++) 182 if (fdp->fd_ofiles[i] == NULL) 183 freefd++; 184 185 /* 186 * Adjust for the fact that the fdesc array may not 187 * have been fully allocated yet. 188 */ 189 if (fdp->fd_nfiles < lim) 190 freefd += (lim - fdp->fd_nfiles); 191 FILEDESC_UNLOCK(fdp); 192 193 sbp->f_flags = 0; 194 sbp->f_bsize = DEV_BSIZE; 195 sbp->f_iosize = DEV_BSIZE; 196 sbp->f_blocks = 2; /* 1K to keep df happy */ 197 sbp->f_bfree = 0; 198 sbp->f_bavail = 0; 199 sbp->f_files = lim + 1; /* Allow for "." */ 200 sbp->f_ffree = freefd; /* See comments above */ 201 if (sbp != &mp->mnt_stat) { 202 sbp->f_type = mp->mnt_vfc->vfc_typenum; 203 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 204 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 205 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 206 } 207 return (0); 208} 209 210static struct vfsops fdesc_vfsops = { 211 fdesc_mount, 212 vfs_stdstart, 213 fdesc_unmount, 214 fdesc_root, 215 vfs_stdquotactl, 216 fdesc_statfs, 217 vfs_stdsync, 218 vfs_stdvget, 219 vfs_stdfhtovp, 220 vfs_stdcheckexp, 221 vfs_stdvptofh, 222 fdesc_init, 223 vfs_stduninit, 224 vfs_stdextattrctl, 225}; 226 227VFS_SET(fdesc_vfsops, fdescfs, VFCF_SYNTHETIC); 228