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 __P((struct mount *mp, char *path, caddr_t data, 62 struct nameidata *ndp, struct thread *td)); 63 static int fdesc_unmount __P((struct mount *mp, int mntflags, 64 struct thread *td)); 65 static int fdesc_statfs __P((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, path, data, ndp, td) 73 struct mount *mp; 74 char *path; 75 caddr_t data; 76 struct nameidata *ndp; 77 struct thread *td; 78 { 79 int error = 0; 80 struct fdescmount *fmp; 81 struct vnode *rvp; 82 83 /* 84 * Update is a no-op 85 */ 86 if (mp->mnt_flag & MNT_UPDATE) 87 return (EOPNOTSUPP); 88 89 error = fdesc_allocvp(Froot, FD_ROOT, mp, &rvp, td); 90 if (error) 91 return (error); 92 93 MALLOC(fmp, struct fdescmount *, sizeof(struct fdescmount), 94 M_FDESCMNT, M_WAITOK); /* XXX */ 95 rvp->v_type = VDIR; 96 rvp->v_flag |= VROOT; 97 fmp->f_root = rvp; 98 /* XXX -- don't mark as local to work around fts() problems */ 99 /*mp->mnt_flag |= MNT_LOCAL;*/ 100 mp->mnt_data = (qaddr_t) fmp; 101 vfs_getnewfsid(mp); 102 103 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, td); 106 return (0); 107 } 108 109 static int 110 fdesc_unmount(mp, mntflags, td) 111 struct mount *mp; 112 int mntflags; 113 struct thread *td; 114 { 115 int error; 116 int flags = 0; 117 118 if (mntflags & MNT_FORCE) 119 flags |= FORCECLOSE; 120 121 /* 122 * Clear out buffer cache. I don't think we 123 * ever get anything cached at this level at the 124 * moment, but who knows... 125 * 126 * There is 1 extra root vnode reference corresponding 127 * to f_root. 128 */ 129 if ((error = vflush(mp, 1, flags)) != 0) 130 return (error); 131 132 /* 133 * Finally, throw away the fdescmount structure 134 */ 135 free(mp->mnt_data, M_FDESCMNT); /* XXX */ 136 mp->mnt_data = 0; 137 138 return (0); 139 } 140 141 int 142 fdesc_root(mp, vpp) 143 struct mount *mp; 144 struct vnode **vpp; 145 { 146 struct thread *td = curthread; /* XXX */ 147 struct vnode *vp; 148 149 /* 150 * Return locked reference to root. 151 */ 152 vp = VFSTOFDESC(mp)->f_root; 153 VREF(vp); 154 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 155 *vpp = vp; 156 return (0); 157 } 158 159 static int 160 fdesc_statfs(mp, sbp, td) 161 struct mount *mp; 162 struct statfs *sbp; 163 struct thread *td; 164 { 165 struct filedesc *fdp; 166 int lim; 167 int i; 168 int last; 169 int freefd; 170 171 /* 172 * Compute number of free file descriptors. 173 * [ Strange results will ensue if the open file 174 * limit is ever reduced below the current number 175 * of open files... ] 176 */ 177 lim = td->td_proc->p_rlimit[RLIMIT_NOFILE].rlim_cur; 178 fdp = td->td_proc->p_fd; 179 FILEDESC_LOCK(fdp); 180 last = min(fdp->fd_nfiles, lim); 181 freefd = 0; 182 for (i = fdp->fd_freefile; i < last; i++) 183 if (fdp->fd_ofiles[i] == NULL) 184 freefd++; 185 186 /* 187 * Adjust for the fact that the fdesc array may not 188 * have been fully allocated yet. 189 */ 190 if (fdp->fd_nfiles < lim) 191 freefd += (lim - fdp->fd_nfiles); 192 FILEDESC_UNLOCK(fdp); 193 194 sbp->f_flags = 0; 195 sbp->f_bsize = DEV_BSIZE; 196 sbp->f_iosize = DEV_BSIZE; 197 sbp->f_blocks = 2; /* 1K to keep df happy */ 198 sbp->f_bfree = 0; 199 sbp->f_bavail = 0; 200 sbp->f_files = lim + 1; /* Allow for "." */ 201 sbp->f_ffree = freefd; /* See comments above */ 202 if (sbp != &mp->mnt_stat) { 203 sbp->f_type = mp->mnt_vfc->vfc_typenum; 204 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 205 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 206 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 207 } 208 return (0); 209 } 210 211 static struct vfsops fdesc_vfsops = { 212 fdesc_mount, 213 vfs_stdstart, 214 fdesc_unmount, 215 fdesc_root, 216 vfs_stdquotactl, 217 fdesc_statfs, 218 vfs_stdsync, 219 vfs_stdvget, 220 vfs_stdfhtovp, 221 vfs_stdcheckexp, 222 vfs_stdvptofh, 223 fdesc_init, 224 vfs_stduninit, 225 vfs_stdextattrctl, 226 }; 227 228 VFS_SET(fdesc_vfsops, fdescfs, VFCF_SYNTHETIC); 229