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 u_int size; 78 struct fdescmount *fmp; 79 struct vnode *rvp; 80 81 /* 82 * Update is a no-op 83 */ 84 if (mp->mnt_flag & MNT_UPDATE) 85 return (EOPNOTSUPP); 86 87 error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp); 88 if (error) 89 return (error); 90 91 MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount), 92 M_FDESCMNT, M_WAITOK); /* XXX */ 93 rvp->v_type = VDIR; 94 rvp->v_flag |= VROOT; 95 fmp->f_root = rvp; 96 /* XXX -- don't mark as local to work around fts() problems */ 97 /*mp->mnt_flag |= MNT_LOCAL;*/ 98 mp->mnt_data = (qaddr_t) fmp; 99 vfs_getnewfsid(mp); 100 101 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 102 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 103 bzero(mp->mnt_stat.f_mntfromname, MNAMELEN); 104 bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc")); 105 (void)fdesc_statfs(mp, &mp->mnt_stat, p); 106 return (0); 107 } 108 109 static int 110 fdesc_unmount(mp, mntflags, p) 111 struct mount *mp; 112 int mntflags; 113 struct proc *p; 114 { 115 int error; 116 int flags = 0; 117 struct vnode *rootvp = VFSTOFDESC(mp)->f_root; 118 119 if (mntflags & MNT_FORCE) 120 flags |= FORCECLOSE; 121 122 /* 123 * Clear out buffer cache. I don't think we 124 * ever get anything cached at this level at the 125 * moment, but who knows... 126 */ 127 if (rootvp->v_usecount > 1) 128 return (EBUSY); 129 if ((error = vflush(mp, rootvp, flags)) != 0) 130 return (error); 131 132 /* 133 * Release reference on underlying root vnode 134 */ 135 vrele(rootvp); 136 /* 137 * And blow it away for future re-use 138 */ 139 vgone(rootvp); 140 /* 141 * Finally, throw away the fdescmount structure 142 */ 143 free(mp->mnt_data, M_FDESCMNT); /* XXX */ 144 mp->mnt_data = 0; 145 146 return (0); 147 } 148 149 int 150 fdesc_root(mp, vpp) 151 struct mount *mp; 152 struct vnode **vpp; 153 { 154 struct proc *p = curproc; /* XXX */ 155 struct vnode *vp; 156 157 /* 158 * Return locked reference to root. 159 */ 160 vp = VFSTOFDESC(mp)->f_root; 161 VREF(vp); 162 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 163 *vpp = vp; 164 return (0); 165 } 166 167 static int 168 fdesc_statfs(mp, sbp, p) 169 struct mount *mp; 170 struct statfs *sbp; 171 struct proc *p; 172 { 173 struct filedesc *fdp; 174 int lim; 175 int i; 176 int last; 177 int freefd; 178 179 /* 180 * Compute number of free file descriptors. 181 * [ Strange results will ensue if the open file 182 * limit is ever reduced below the current number 183 * of open files... ] 184 */ 185 lim = p->p_rlimit[RLIMIT_NOFILE].rlim_cur; 186 fdp = p->p_fd; 187 last = min(fdp->fd_nfiles, lim); 188 freefd = 0; 189 for (i = fdp->fd_freefile; i < last; i++) 190 if (fdp->fd_ofiles[i] == NULL) 191 freefd++; 192 193 /* 194 * Adjust for the fact that the fdesc array may not 195 * have been fully allocated yet. 196 */ 197 if (fdp->fd_nfiles < lim) 198 freefd += (lim - fdp->fd_nfiles); 199 200 sbp->f_flags = 0; 201 sbp->f_bsize = DEV_BSIZE; 202 sbp->f_iosize = DEV_BSIZE; 203 sbp->f_blocks = 2; /* 1K to keep df happy */ 204 sbp->f_bfree = 0; 205 sbp->f_bavail = 0; 206 sbp->f_files = lim + 1; /* Allow for "." */ 207 sbp->f_ffree = freefd; /* See comments above */ 208 if (sbp != &mp->mnt_stat) { 209 sbp->f_type = mp->mnt_vfc->vfc_typenum; 210 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 211 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 212 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 213 } 214 return (0); 215 } 216 217 static struct vfsops fdesc_vfsops = { 218 fdesc_mount, 219 vfs_stdstart, 220 fdesc_unmount, 221 fdesc_root, 222 vfs_stdquotactl, 223 fdesc_statfs, 224 vfs_stdsync, 225 vfs_stdvget, 226 vfs_stdfhtovp, 227 vfs_stdcheckexp, 228 vfs_stdvptofh, 229 fdesc_init, 230 vfs_stduninit, 231 vfs_stdextattrctl, 232 }; 233 234 VFS_SET(fdesc_vfsops, fdesc, VFCF_SYNTHETIC); 235