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_mount_t fdesc_mount; 58 static vfs_unmount_t fdesc_unmount; 59 static vfs_statfs_t fdesc_statfs; 60 static vfs_root_t fdesc_root; 61 62 /* 63 * Mount the per-process file descriptors (/dev/fd) 64 */ 65 static int 66 fdesc_mount(struct mount *mp, struct thread *td) 67 { 68 int error = 0; 69 struct fdescmount *fmp; 70 struct vnode *rvp; 71 72 /* 73 * Update is a no-op 74 */ 75 if (mp->mnt_flag & (MNT_UPDATE | MNT_ROOTFS)) 76 return (EOPNOTSUPP); 77 78 error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp, td); 79 if (error) 80 return (error); 81 82 MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount), 83 M_FDESCMNT, M_WAITOK); /* XXX */ 84 rvp->v_type = VDIR; 85 rvp->v_vflag |= VV_ROOT; 86 fmp->f_root = rvp; 87 /* XXX -- don't mark as local to work around fts() problems */ 88 /*mp->mnt_flag |= MNT_LOCAL;*/ 89 mp->mnt_data = (qaddr_t) fmp; 90 vfs_getnewfsid(mp); 91 92 vfs_mountedfrom(mp, "fdescfs"); 93 return (0); 94 } 95 96 static int 97 fdesc_unmount(mp, mntflags, td) 98 struct mount *mp; 99 int mntflags; 100 struct thread *td; 101 { 102 int error; 103 int flags = 0; 104 105 if (mntflags & MNT_FORCE) 106 flags |= FORCECLOSE; 107 108 /* 109 * Clear out buffer cache. I don't think we 110 * ever get anything cached at this level at the 111 * moment, but who knows... 112 * 113 * There is 1 extra root vnode reference corresponding 114 * to f_root. 115 */ 116 if ((error = vflush(mp, 1, flags, td)) != 0) 117 return (error); 118 119 /* 120 * Finally, throw away the fdescmount structure 121 */ 122 free(mp->mnt_data, M_FDESCMNT); /* XXX */ 123 mp->mnt_data = 0; 124 125 return (0); 126 } 127 128 static int 129 fdesc_root(mp, vpp, td) 130 struct mount *mp; 131 struct vnode **vpp; 132 struct thread *td; 133 { 134 struct vnode *vp; 135 136 /* 137 * Return locked reference to root. 138 */ 139 vp = VFSTOFDESC(mp)->f_root; 140 VREF(vp); 141 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 142 *vpp = vp; 143 return (0); 144 } 145 146 static int 147 fdesc_statfs(mp, sbp, td) 148 struct mount *mp; 149 struct statfs *sbp; 150 struct thread *td; 151 { 152 struct filedesc *fdp; 153 int lim; 154 int i; 155 int last; 156 int freefd; 157 158 /* 159 * Compute number of free file descriptors. 160 * [ Strange results will ensue if the open file 161 * limit is ever reduced below the current number 162 * of open files... ] 163 */ 164 PROC_LOCK(td->td_proc); 165 lim = lim_cur(td->td_proc, RLIMIT_NOFILE); 166 PROC_UNLOCK(td->td_proc); 167 fdp = td->td_proc->p_fd; 168 FILEDESC_LOCK_FAST(fdp); 169 last = min(fdp->fd_nfiles, lim); 170 freefd = 0; 171 for (i = fdp->fd_freefile; i < last; i++) 172 if (fdp->fd_ofiles[i] == NULL) 173 freefd++; 174 175 /* 176 * Adjust for the fact that the fdesc array may not 177 * have been fully allocated yet. 178 */ 179 if (fdp->fd_nfiles < lim) 180 freefd += (lim - fdp->fd_nfiles); 181 FILEDESC_UNLOCK_FAST(fdp); 182 183 sbp->f_flags = 0; 184 sbp->f_bsize = DEV_BSIZE; 185 sbp->f_iosize = DEV_BSIZE; 186 sbp->f_blocks = 2; /* 1K to keep df happy */ 187 sbp->f_bfree = 0; 188 sbp->f_bavail = 0; 189 sbp->f_files = lim + 1; /* Allow for "." */ 190 sbp->f_ffree = freefd; /* See comments above */ 191 return (0); 192 } 193 194 static struct vfsops fdesc_vfsops = { 195 .vfs_init = fdesc_init, 196 .vfs_mount = fdesc_mount, 197 .vfs_root = fdesc_root, 198 .vfs_statfs = fdesc_statfs, 199 .vfs_unmount = fdesc_unmount, 200 }; 201 202 VFS_SET(fdesc_vfsops, fdescfs, VFCF_SYNTHETIC); 203