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 * $FreeBSD$ 39 */ 40 41 /* 42 * /dev/fd Filesystem 43 */ 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/proc.h> 49 #include <sys/resourcevar.h> 50 #include <sys/filedesc.h> 51 #include <sys/vnode.h> 52 #include <sys/mount.h> 53 #include <sys/malloc.h> 54 #include <miscfs/fdesc/fdesc.h> 55 56 static MALLOC_DEFINE(M_FDESCMNT, "FDESC mount", "FDESC mount structure"); 57 58 static int fdesc_mount __P((struct mount *mp, char *path, caddr_t data, 59 struct nameidata *ndp, struct proc *p)); 60 static int fdesc_unmount __P((struct mount *mp, int mntflags, 61 struct proc *p)); 62 static int fdesc_statfs __P((struct mount *mp, struct statfs *sbp, 63 struct proc *p)); 64 65 /* 66 * Mount the per-process file descriptors (/dev/fd) 67 */ 68 static int 69 fdesc_mount(mp, path, data, ndp, p) 70 struct mount *mp; 71 char *path; 72 caddr_t data; 73 struct nameidata *ndp; 74 struct proc *p; 75 { 76 int error = 0; 77 struct fdescmount *fmp; 78 struct vnode *rvp; 79 80 /* 81 * Update is a no-op 82 */ 83 if (mp->mnt_flag & MNT_UPDATE) 84 return (EOPNOTSUPP); 85 86 error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp, p); 87 if (error) 88 return (error); 89 90 MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount), 91 M_FDESCMNT, M_WAITOK); /* XXX */ 92 rvp->v_type = VDIR; 93 rvp->v_flag |= VROOT; 94 fmp->f_root = rvp; 95 /* XXX -- don't mark as local to work around fts() problems */ 96 /*mp->mnt_flag |= MNT_LOCAL;*/ 97 mp->mnt_data = (qaddr_t) fmp; 98 vfs_getnewfsid(mp); 99 100 bzero(mp->mnt_stat.f_mntfromname, MNAMELEN); 101 bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc")); 102 (void)fdesc_statfs(mp, &mp->mnt_stat, p); 103 return (0); 104 } 105 106 static int 107 fdesc_unmount(mp, mntflags, p) 108 struct mount *mp; 109 int mntflags; 110 struct proc *p; 111 { 112 int error; 113 int flags = 0; 114 struct vnode *rootvp = VFSTOFDESC(mp)->f_root; 115 116 if (mntflags & MNT_FORCE) 117 flags |= FORCECLOSE; 118 119 /* 120 * Clear out buffer cache. I don't think we 121 * ever get anything cached at this level at the 122 * moment, but who knows... 123 */ 124 if (rootvp->v_usecount > 1) 125 return (EBUSY); 126 if ((error = vflush(mp, rootvp, flags)) != 0) 127 return (error); 128 129 /* 130 * Release reference on underlying root vnode 131 */ 132 vrele(rootvp); 133 /* 134 * And blow it away for future re-use 135 */ 136 vgone(rootvp); 137 /* 138 * Finally, throw away the fdescmount structure 139 */ 140 free(mp->mnt_data, M_FDESCMNT); /* XXX */ 141 mp->mnt_data = 0; 142 143 return (0); 144 } 145 146 int 147 fdesc_root(mp, vpp) 148 struct mount *mp; 149 struct vnode **vpp; 150 { 151 struct proc *p = curproc; /* XXX */ 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, p); 160 *vpp = vp; 161 return (0); 162 } 163 164 static int 165 fdesc_statfs(mp, sbp, p) 166 struct mount *mp; 167 struct statfs *sbp; 168 struct proc *p; 169 { 170 struct filedesc *fdp; 171 int lim; 172 int i; 173 int last; 174 int freefd; 175 176 /* 177 * Compute number of free file descriptors. 178 * [ Strange results will ensue if the open file 179 * limit is ever reduced below the current number 180 * of open files... ] 181 */ 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_flags = 0; 198 sbp->f_bsize = 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_files = lim + 1; /* Allow for "." */ 204 sbp->f_ffree = freefd; /* See comments above */ 205 if (sbp != &mp->mnt_stat) { 206 sbp->f_type = mp->mnt_vfc->vfc_typenum; 207 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 208 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 209 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 210 } 211 return (0); 212 } 213 214 static struct vfsops fdesc_vfsops = { 215 fdesc_mount, 216 vfs_stdstart, 217 fdesc_unmount, 218 fdesc_root, 219 vfs_stdquotactl, 220 fdesc_statfs, 221 vfs_stdsync, 222 vfs_stdvget, 223 vfs_stdfhtovp, 224 vfs_stdcheckexp, 225 vfs_stdvptofh, 226 fdesc_init, 227 vfs_stduninit, 228 vfs_stdextattrctl, 229 }; 230 231 VFS_SET(fdesc_vfsops, fdesc, VFCF_SYNTHETIC); 232