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/filedesc.h> 48 #include <sys/kernel.h> 49 #include <sys/lock.h> 50 #include <sys/mutex.h> 51 #include <sys/malloc.h> 52 #include <sys/mount.h> 53 #include <sys/proc.h> 54 #include <sys/resourcevar.h> 55 #include <sys/vnode.h> 56 57 #include <fs/fdescfs/fdesc.h> 58 59 static MALLOC_DEFINE(M_FDESCMNT, "FDESC mount", "FDESC mount structure"); 60 61 static int fdesc_mount(struct mount *mp, struct nameidata *ndp, 62 struct thread *td); 63 static int fdesc_unmount(struct mount *mp, int mntflags, 64 struct thread *td); 65 static int fdesc_statfs(struct mount *mp, struct statfs *sbp, 66 struct thread *td); 67 68 /* 69 * Mount the per-process file descriptors (/dev/fd) 70 */ 71 static int 72 fdesc_mount(mp, ndp, td) 73 struct mount *mp; 74 struct nameidata *ndp; 75 struct thread *td; 76 { 77 int error = 0; 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, td); 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_vflag |= VV_ROOT; 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 bzero(mp->mnt_stat.f_mntfromname, MNAMELEN); 102 bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc")); 103 (void)fdesc_statfs(mp, &mp->mnt_stat, td); 104 return (0); 105 } 106 107 static int 108 fdesc_unmount(mp, mntflags, td) 109 struct mount *mp; 110 int mntflags; 111 struct thread *td; 112 { 113 int error; 114 int flags = 0; 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 * There is 1 extra root vnode reference corresponding 125 * to f_root. 126 */ 127 if ((error = vflush(mp, 1, flags)) != 0) 128 return (error); 129 130 /* 131 * Finally, throw away the fdescmount structure 132 */ 133 free(mp->mnt_data, M_FDESCMNT); /* XXX */ 134 mp->mnt_data = 0; 135 136 return (0); 137 } 138 139 int 140 fdesc_root(mp, vpp) 141 struct mount *mp; 142 struct vnode **vpp; 143 { 144 struct thread *td = curthread; /* XXX */ 145 struct vnode *vp; 146 147 /* 148 * Return locked reference to root. 149 */ 150 vp = VFSTOFDESC(mp)->f_root; 151 VREF(vp); 152 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 153 *vpp = vp; 154 return (0); 155 } 156 157 static int 158 fdesc_statfs(mp, sbp, td) 159 struct mount *mp; 160 struct statfs *sbp; 161 struct thread *td; 162 { 163 struct filedesc *fdp; 164 int lim; 165 int i; 166 int last; 167 int freefd; 168 169 /* 170 * Compute number of free file descriptors. 171 * [ Strange results will ensue if the open file 172 * limit is ever reduced below the current number 173 * of open files... ] 174 */ 175 lim = td->td_proc->p_rlimit[RLIMIT_NOFILE].rlim_cur; 176 fdp = td->td_proc->p_fd; 177 FILEDESC_LOCK(fdp); 178 last = min(fdp->fd_nfiles, lim); 179 freefd = 0; 180 for (i = fdp->fd_freefile; i < last; i++) 181 if (fdp->fd_ofiles[i] == NULL) 182 freefd++; 183 184 /* 185 * Adjust for the fact that the fdesc array may not 186 * have been fully allocated yet. 187 */ 188 if (fdp->fd_nfiles < lim) 189 freefd += (lim - fdp->fd_nfiles); 190 FILEDESC_UNLOCK(fdp); 191 192 sbp->f_flags = 0; 193 sbp->f_bsize = DEV_BSIZE; 194 sbp->f_iosize = DEV_BSIZE; 195 sbp->f_blocks = 2; /* 1K to keep df happy */ 196 sbp->f_bfree = 0; 197 sbp->f_bavail = 0; 198 sbp->f_files = lim + 1; /* Allow for "." */ 199 sbp->f_ffree = freefd; /* See comments above */ 200 if (sbp != &mp->mnt_stat) { 201 sbp->f_type = mp->mnt_vfc->vfc_typenum; 202 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 203 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 204 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 205 } 206 return (0); 207 } 208 209 static struct vfsops fdesc_vfsops = { 210 NULL, 211 vfs_stdstart, 212 fdesc_unmount, 213 fdesc_root, 214 vfs_stdquotactl, 215 fdesc_statfs, 216 vfs_stdsync, 217 vfs_stdvget, 218 vfs_stdfhtovp, 219 vfs_stdcheckexp, 220 vfs_stdvptofh, 221 fdesc_init, 222 vfs_stduninit, 223 vfs_stdextattrctl, 224 fdesc_mount, 225 }; 226 227 VFS_SET(fdesc_vfsops, fdescfs, VFCF_SYNTHETIC); 228