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