1*7c478bd9Sstevel@tonic-gate /* 2*7c478bd9Sstevel@tonic-gate * CDDL HEADER START 3*7c478bd9Sstevel@tonic-gate * 4*7c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the 5*7c478bd9Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only 6*7c478bd9Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance 7*7c478bd9Sstevel@tonic-gate * with the License. 8*7c478bd9Sstevel@tonic-gate * 9*7c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10*7c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 11*7c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions 12*7c478bd9Sstevel@tonic-gate * and limitations under the License. 13*7c478bd9Sstevel@tonic-gate * 14*7c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 15*7c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16*7c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 17*7c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 18*7c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 19*7c478bd9Sstevel@tonic-gate * 20*7c478bd9Sstevel@tonic-gate * CDDL HEADER END 21*7c478bd9Sstevel@tonic-gate */ 22*7c478bd9Sstevel@tonic-gate /* 23*7c478bd9Sstevel@tonic-gate * Copyright 2003 Sun Microsystems, Inc. All rights reserved. 24*7c478bd9Sstevel@tonic-gate * Use is subject to license terms. 25*7c478bd9Sstevel@tonic-gate */ 26*7c478bd9Sstevel@tonic-gate 27*7c478bd9Sstevel@tonic-gate /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 28*7c478bd9Sstevel@tonic-gate /* All Rights Reserved */ 29*7c478bd9Sstevel@tonic-gate 30*7c478bd9Sstevel@tonic-gate /* 31*7c478bd9Sstevel@tonic-gate * Portions of this source code were derived from Berkeley 4.3 BSD 32*7c478bd9Sstevel@tonic-gate * under license from the Regents of the University of California. 33*7c478bd9Sstevel@tonic-gate */ 34*7c478bd9Sstevel@tonic-gate 35*7c478bd9Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 36*7c478bd9Sstevel@tonic-gate 37*7c478bd9Sstevel@tonic-gate #include <sys/types.h> 38*7c478bd9Sstevel@tonic-gate #include <sys/t_lock.h> 39*7c478bd9Sstevel@tonic-gate #include <sys/param.h> 40*7c478bd9Sstevel@tonic-gate #include <sys/errno.h> 41*7c478bd9Sstevel@tonic-gate #include <sys/fstyp.h> 42*7c478bd9Sstevel@tonic-gate #include <sys/kmem.h> 43*7c478bd9Sstevel@tonic-gate #include <sys/systm.h> 44*7c478bd9Sstevel@tonic-gate #include <sys/mount.h> 45*7c478bd9Sstevel@tonic-gate #include <sys/vfs.h> 46*7c478bd9Sstevel@tonic-gate #include <sys/cred.h> 47*7c478bd9Sstevel@tonic-gate #include <sys/vnode.h> 48*7c478bd9Sstevel@tonic-gate #include <sys/cmn_err.h> 49*7c478bd9Sstevel@tonic-gate #include <sys/debug.h> 50*7c478bd9Sstevel@tonic-gate #include <sys/pathname.h> 51*7c478bd9Sstevel@tonic-gate #include <sys/policy.h> 52*7c478bd9Sstevel@tonic-gate #include <sys/zone.h> 53*7c478bd9Sstevel@tonic-gate 54*7c478bd9Sstevel@tonic-gate 55*7c478bd9Sstevel@tonic-gate /* 56*7c478bd9Sstevel@tonic-gate * New umount() system call (for force unmount flag and perhaps others later). 57*7c478bd9Sstevel@tonic-gate */ 58*7c478bd9Sstevel@tonic-gate int 59*7c478bd9Sstevel@tonic-gate umount2(char *pathp, int flag) 60*7c478bd9Sstevel@tonic-gate { 61*7c478bd9Sstevel@tonic-gate struct pathname pn; 62*7c478bd9Sstevel@tonic-gate struct vfs *vfsp; 63*7c478bd9Sstevel@tonic-gate int error; 64*7c478bd9Sstevel@tonic-gate 65*7c478bd9Sstevel@tonic-gate /* 66*7c478bd9Sstevel@tonic-gate * Some flags are disallowed through the system call interface. 67*7c478bd9Sstevel@tonic-gate */ 68*7c478bd9Sstevel@tonic-gate flag &= MS_UMOUNT_MASK; 69*7c478bd9Sstevel@tonic-gate 70*7c478bd9Sstevel@tonic-gate /* 71*7c478bd9Sstevel@tonic-gate * Lookup user-supplied name by trying to match it against the 72*7c478bd9Sstevel@tonic-gate * mount points recorded at mount time. If no match is found 73*7c478bd9Sstevel@tonic-gate * (which can happen if the path to the mount point is specified 74*7c478bd9Sstevel@tonic-gate * differently between mount & umount, or if a block device were 75*7c478bd9Sstevel@tonic-gate * passed to umount) then we fall back to calling lookupname() 76*7c478bd9Sstevel@tonic-gate * to find the vfs. Doing it this way prevents calling lookupname() 77*7c478bd9Sstevel@tonic-gate * in most cases and that allows forcible umount to work even if 78*7c478bd9Sstevel@tonic-gate * lookupname() would hang (i.e. because an NFS server is dead). 79*7c478bd9Sstevel@tonic-gate */ 80*7c478bd9Sstevel@tonic-gate 81*7c478bd9Sstevel@tonic-gate if (error = pn_get(pathp, UIO_USERSPACE, &pn)) 82*7c478bd9Sstevel@tonic-gate return (set_errno(error)); 83*7c478bd9Sstevel@tonic-gate 84*7c478bd9Sstevel@tonic-gate /* 85*7c478bd9Sstevel@tonic-gate * Only a privileged user is allowed to bypass the security 86*7c478bd9Sstevel@tonic-gate * checks done by lookupname() and use the results from 87*7c478bd9Sstevel@tonic-gate * vfs_mntpoint2vfsp() instead. It could be argued that the 88*7c478bd9Sstevel@tonic-gate * proper check is FILE_DAC_SEARCH but we put it all 89*7c478bd9Sstevel@tonic-gate * under the mount privilege. Also, make sure the caller 90*7c478bd9Sstevel@tonic-gate * isn't in an environment with an alternate root (to the zone's root) 91*7c478bd9Sstevel@tonic-gate * directory, i.e. chroot(2). 92*7c478bd9Sstevel@tonic-gate */ 93*7c478bd9Sstevel@tonic-gate if (secpolicy_fs_unmount(CRED(), NULL) != 0 || 94*7c478bd9Sstevel@tonic-gate (PTOU(curproc)->u_rdir != NULL && 95*7c478bd9Sstevel@tonic-gate PTOU(curproc)->u_rdir != curproc->p_zone->zone_rootvp) || 96*7c478bd9Sstevel@tonic-gate (vfsp = vfs_mntpoint2vfsp(pn.pn_path)) == NULL) { 97*7c478bd9Sstevel@tonic-gate vnode_t *fsrootvp; 98*7c478bd9Sstevel@tonic-gate 99*7c478bd9Sstevel@tonic-gate /* fall back to lookupname() on path given to us */ 100*7c478bd9Sstevel@tonic-gate if (error = lookupname(pn.pn_path, UIO_SYSSPACE, FOLLOW, 101*7c478bd9Sstevel@tonic-gate NULLVPP, &fsrootvp)) { 102*7c478bd9Sstevel@tonic-gate pn_free(&pn); 103*7c478bd9Sstevel@tonic-gate return (set_errno(error)); 104*7c478bd9Sstevel@tonic-gate } 105*7c478bd9Sstevel@tonic-gate /* 106*7c478bd9Sstevel@tonic-gate * Find the vfs to be unmounted. The caller may have specified 107*7c478bd9Sstevel@tonic-gate * either the directory mount point (preferred) or else (for a 108*7c478bd9Sstevel@tonic-gate * disk-based file system) the block device which was mounted. 109*7c478bd9Sstevel@tonic-gate * Check to see which it is; if it's the device, search the VFS 110*7c478bd9Sstevel@tonic-gate * list to find the associated vfs entry. 111*7c478bd9Sstevel@tonic-gate */ 112*7c478bd9Sstevel@tonic-gate if (fsrootvp->v_flag & VROOT) { 113*7c478bd9Sstevel@tonic-gate vfsp = fsrootvp->v_vfsp; 114*7c478bd9Sstevel@tonic-gate VFS_HOLD(vfsp); 115*7c478bd9Sstevel@tonic-gate } else if (fsrootvp->v_type == VBLK) 116*7c478bd9Sstevel@tonic-gate vfsp = vfs_dev2vfsp(fsrootvp->v_rdev); 117*7c478bd9Sstevel@tonic-gate else 118*7c478bd9Sstevel@tonic-gate vfsp = NULL; 119*7c478bd9Sstevel@tonic-gate 120*7c478bd9Sstevel@tonic-gate VN_RELE(fsrootvp); 121*7c478bd9Sstevel@tonic-gate 122*7c478bd9Sstevel@tonic-gate if (vfsp == NULL) { 123*7c478bd9Sstevel@tonic-gate pn_free(&pn); 124*7c478bd9Sstevel@tonic-gate return (set_errno(EINVAL)); 125*7c478bd9Sstevel@tonic-gate } 126*7c478bd9Sstevel@tonic-gate } 127*7c478bd9Sstevel@tonic-gate pn_free(&pn); 128*7c478bd9Sstevel@tonic-gate 129*7c478bd9Sstevel@tonic-gate /* 130*7c478bd9Sstevel@tonic-gate * Protect the call to vn_vfswlock() with the vfs reflock. This 131*7c478bd9Sstevel@tonic-gate * ensures vfs_vnodecovered will either be NULL (because someone 132*7c478bd9Sstevel@tonic-gate * beat us to the umount) or valid (because vfs_lock() prevents 133*7c478bd9Sstevel@tonic-gate * another umount from getting through here until we've called 134*7c478bd9Sstevel@tonic-gate * vn_vfswlock() on the covered vnode). 135*7c478bd9Sstevel@tonic-gate * 136*7c478bd9Sstevel@tonic-gate * At one point, we did the non-blocking version (vfs_lock()), 137*7c478bd9Sstevel@tonic-gate * and if it failed, bailed out with EBUSY. However, dounmount() 138*7c478bd9Sstevel@tonic-gate * calls vfs_lock_wait() and we drop the vfs lock before calling 139*7c478bd9Sstevel@tonic-gate * dounmount(), so there's no difference between waiting here 140*7c478bd9Sstevel@tonic-gate * for the lock or waiting there because grabbed it as soon as 141*7c478bd9Sstevel@tonic-gate * we drop it below. No returning with EBUSY at this point 142*7c478bd9Sstevel@tonic-gate * reduces the number of spurious unmount failures that happen 143*7c478bd9Sstevel@tonic-gate * as a side-effect of fsflush() and other mount and unmount 144*7c478bd9Sstevel@tonic-gate * operations that might be going on simultaneously. 145*7c478bd9Sstevel@tonic-gate */ 146*7c478bd9Sstevel@tonic-gate vfs_lock_wait(vfsp); 147*7c478bd9Sstevel@tonic-gate 148*7c478bd9Sstevel@tonic-gate /* 149*7c478bd9Sstevel@tonic-gate * Call vn_vfswlock() on the covered vnode so that dounmount() 150*7c478bd9Sstevel@tonic-gate * can do its thing. It will call the corresponding vn_vfsunlock(). 151*7c478bd9Sstevel@tonic-gate * Note that vfsp->vfs_vnodecovered can be NULL here, either because 152*7c478bd9Sstevel@tonic-gate * someone did umount on "/" or because someone beat us to the umount 153*7c478bd9Sstevel@tonic-gate * before we did the vfs_lock() above. In these cases, vn_vfswlock() 154*7c478bd9Sstevel@tonic-gate * returns EBUSY and we just pass that up. Also note that we're 155*7c478bd9Sstevel@tonic-gate * looking at a vnode without doing a VN_HOLD() on it. This is 156*7c478bd9Sstevel@tonic-gate * safe because it can't go away while something is mounted on it 157*7c478bd9Sstevel@tonic-gate * and we're locking out other umounts at this point. 158*7c478bd9Sstevel@tonic-gate */ 159*7c478bd9Sstevel@tonic-gate if (vn_vfswlock(vfsp->vfs_vnodecovered)) { 160*7c478bd9Sstevel@tonic-gate vfs_unlock(vfsp); 161*7c478bd9Sstevel@tonic-gate VFS_RELE(vfsp); 162*7c478bd9Sstevel@tonic-gate return (set_errno(EBUSY)); 163*7c478bd9Sstevel@tonic-gate } 164*7c478bd9Sstevel@tonic-gate 165*7c478bd9Sstevel@tonic-gate /* 166*7c478bd9Sstevel@tonic-gate * Now that the VVFSLOCK in the covered vnode is protecting this 167*7c478bd9Sstevel@tonic-gate * path, we don't need the vfs reflock or the hold on the vfs anymore. 168*7c478bd9Sstevel@tonic-gate */ 169*7c478bd9Sstevel@tonic-gate vfs_unlock(vfsp); 170*7c478bd9Sstevel@tonic-gate VFS_RELE(vfsp); 171*7c478bd9Sstevel@tonic-gate 172*7c478bd9Sstevel@tonic-gate /* 173*7c478bd9Sstevel@tonic-gate * Perform the unmount. 174*7c478bd9Sstevel@tonic-gate */ 175*7c478bd9Sstevel@tonic-gate if ((error = dounmount(vfsp, flag, CRED())) != 0) 176*7c478bd9Sstevel@tonic-gate return (set_errno(error)); 177*7c478bd9Sstevel@tonic-gate return (0); 178*7c478bd9Sstevel@tonic-gate } 179*7c478bd9Sstevel@tonic-gate 180*7c478bd9Sstevel@tonic-gate /* 181*7c478bd9Sstevel@tonic-gate * Old umount() system call for compatibility. 182*7c478bd9Sstevel@tonic-gate * Changes due to support for forced unmount. 183*7c478bd9Sstevel@tonic-gate */ 184*7c478bd9Sstevel@tonic-gate int 185*7c478bd9Sstevel@tonic-gate umount(char *pathp) 186*7c478bd9Sstevel@tonic-gate { 187*7c478bd9Sstevel@tonic-gate return (umount2(pathp, 0)); 188*7c478bd9Sstevel@tonic-gate } 189