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 vfs_nmount_t fdesc_mount; 62 static vfs_unmount_t fdesc_unmount; 63 static vfs_statfs_t fdesc_statfs; 64 65 /* 66 * Mount the per-process file descriptors (/dev/fd) 67 */ 68 static int 69 fdesc_mount(mp, ndp, td) 70 struct mount *mp; 71 struct nameidata *ndp; 72 struct thread *td; 73 { 74 int error = 0; 75 struct fdescmount *fmp; 76 struct vnode *rvp; 77 78 /* 79 * Update is a no-op 80 */ 81 if (mp->mnt_flag & MNT_UPDATE) 82 return (EOPNOTSUPP); 83 84 error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp, td); 85 if (error) 86 return (error); 87 88 MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount), 89 M_FDESCMNT, M_WAITOK); /* XXX */ 90 rvp->v_type = VDIR; 91 rvp->v_vflag |= VV_ROOT; 92 fmp->f_root = rvp; 93 /* XXX -- don't mark as local to work around fts() problems */ 94 /*mp->mnt_flag |= MNT_LOCAL;*/ 95 mp->mnt_data = (qaddr_t) fmp; 96 vfs_getnewfsid(mp); 97 98 bzero(mp->mnt_stat.f_mntfromname, MNAMELEN); 99 bcopy("fdescfs", mp->mnt_stat.f_mntfromname, sizeof("fdescfs")); 100 (void)fdesc_statfs(mp, &mp->mnt_stat, td); 101 return (0); 102 } 103 104 static int 105 fdesc_unmount(mp, mntflags, td) 106 struct mount *mp; 107 int mntflags; 108 struct thread *td; 109 { 110 int error; 111 int flags = 0; 112 113 if (mntflags & MNT_FORCE) 114 flags |= FORCECLOSE; 115 116 /* 117 * Clear out buffer cache. I don't think we 118 * ever get anything cached at this level at the 119 * moment, but who knows... 120 * 121 * There is 1 extra root vnode reference corresponding 122 * to f_root. 123 */ 124 if ((error = vflush(mp, 1, flags)) != 0) 125 return (error); 126 127 /* 128 * Finally, throw away the fdescmount structure 129 */ 130 free(mp->mnt_data, M_FDESCMNT); /* XXX */ 131 mp->mnt_data = 0; 132 133 return (0); 134 } 135 136 int 137 fdesc_root(mp, vpp) 138 struct mount *mp; 139 struct vnode **vpp; 140 { 141 struct thread *td = curthread; /* XXX */ 142 struct vnode *vp; 143 144 /* 145 * Return locked reference to root. 146 */ 147 vp = VFSTOFDESC(mp)->f_root; 148 VREF(vp); 149 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 150 *vpp = vp; 151 return (0); 152 } 153 154 static int 155 fdesc_statfs(mp, sbp, td) 156 struct mount *mp; 157 struct statfs *sbp; 158 struct thread *td; 159 { 160 struct filedesc *fdp; 161 int lim; 162 int i; 163 int last; 164 int freefd; 165 166 /* 167 * Compute number of free file descriptors. 168 * [ Strange results will ensue if the open file 169 * limit is ever reduced below the current number 170 * of open files... ] 171 */ 172 lim = td->td_proc->p_rlimit[RLIMIT_NOFILE].rlim_cur; 173 fdp = td->td_proc->p_fd; 174 FILEDESC_LOCK(fdp); 175 last = min(fdp->fd_nfiles, lim); 176 freefd = 0; 177 for (i = fdp->fd_freefile; i < last; i++) 178 if (fdp->fd_ofiles[i] == NULL) 179 freefd++; 180 181 /* 182 * Adjust for the fact that the fdesc array may not 183 * have been fully allocated yet. 184 */ 185 if (fdp->fd_nfiles < lim) 186 freefd += (lim - fdp->fd_nfiles); 187 FILEDESC_UNLOCK(fdp); 188 189 sbp->f_flags = 0; 190 sbp->f_bsize = DEV_BSIZE; 191 sbp->f_iosize = DEV_BSIZE; 192 sbp->f_blocks = 2; /* 1K to keep df happy */ 193 sbp->f_bfree = 0; 194 sbp->f_bavail = 0; 195 sbp->f_files = lim + 1; /* Allow for "." */ 196 sbp->f_ffree = freefd; /* See comments above */ 197 if (sbp != &mp->mnt_stat) { 198 sbp->f_type = mp->mnt_vfc->vfc_typenum; 199 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 200 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 201 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 202 } 203 return (0); 204 } 205 206 static struct vfsops fdesc_vfsops = { 207 .vfs_init = fdesc_init, 208 .vfs_nmount = fdesc_mount, 209 .vfs_root = fdesc_root, 210 .vfs_statfs = fdesc_statfs, 211 .vfs_unmount = fdesc_unmount, 212 }; 213 214 VFS_SET(fdesc_vfsops, fdescfs, VFCF_SYNTHETIC); 215