chdir.c revision 5753:d64b1f799526
1314564Sdim/* 2314564Sdim * CDDL HEADER START 3254721Semaste * 4353358Sdim * The contents of this file are subject to the terms of the 5353358Sdim * Common Development and Distribution License (the "License"). 6353358Sdim * You may not use this file except in compliance with the License. 7254721Semaste * 8254721Semaste * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9254721Semaste * or http://www.opensolaris.org/os/licensing. 10254721Semaste * See the License for the specific language governing permissions 11254721Semaste * and limitations under the License. 12254721Semaste * 13254721Semaste * When distributing Covered Code, include this CDDL HEADER in each 14254721Semaste * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15344779Sdim * If applicable, add the following below this CDDL HEADER, with the 16314564Sdim * fields enclosed by brackets "[]" replaced with your own identifying 17254721Semaste * information: Portions Copyright [yyyy] [name of copyright owner] 18254721Semaste * 19254721Semaste * CDDL HEADER END 20314564Sdim */ 21314564Sdim/* 22254721Semaste * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23254721Semaste * Use is subject to license terms. 24353358Sdim */ 25314564Sdim 26314564Sdim/* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 27314564Sdim/* All Rights Reserved */ 28314564Sdim 29353358Sdim/* 30296417Sdim * Portions of this source code were derived from Berkeley 4.3 BSD 31314564Sdim * under license from the Regents of the University of California. 32314564Sdim */ 33254721Semaste 34314564Sdim#pragma ident "%Z%%M% %I% %E% SMI" 35314564Sdim 36314564Sdim#include <sys/param.h> 37314564Sdim#include <sys/isa_defs.h> 38314564Sdim#include <sys/types.h> 39314564Sdim#include <sys/sysmacros.h> 40314564Sdim#include <sys/cred.h> 41314564Sdim#include <sys/user.h> 42314564Sdim#include <sys/systm.h> 43314564Sdim#include <sys/errno.h> 44314564Sdim#include <sys/fcntl.h> 45314564Sdim#include <sys/pathname.h> 46314564Sdim#include <sys/var.h> 47314564Sdim#include <sys/vfs.h> 48314564Sdim#include <sys/vnode.h> 49314564Sdim#include <sys/file.h> 50314564Sdim#include <sys/mode.h> 51314564Sdim#include <sys/proc.h> 52314564Sdim#include <sys/uio.h> 53314564Sdim#include <sys/poll.h> 54314564Sdim#include <sys/kmem.h> 55314564Sdim#include <sys/filio.h> 56314564Sdim#include <sys/cmn_err.h> 57314564Sdim#include <sys/policy.h> 58314564Sdim#include <sys/zone.h> 59314564Sdim 60314564Sdim#include <sys/debug.h> 61254721Semaste#include <c2/audit.h> 62314564Sdim#include <fs/fs_subr.h> 63254721Semaste 64314564Sdim/* 65314564Sdim * Change current working directory ("."). 66314564Sdim */ 67314564Sdimstatic int chdirec(vnode_t *, int ischroot, int do_traverse); 68254721Semaste 69314564Sdimint 70314564Sdimchdir(char *fname) 71314564Sdim{ 72314564Sdim vnode_t *vp; 73314564Sdim int error; 74254721Semaste int estale_retry = 0; 75314564Sdim 76314564Sdimlookup: 77254721Semaste if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) { 78314564Sdim if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 79314564Sdim goto lookup; 80314564Sdim return (set_errno(error)); 81296417Sdim } 82314564Sdim 83314564Sdim error = chdirec(vp, 0, 1); 84314564Sdim if (error) { 85296417Sdim if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 86254721Semaste goto lookup; 87314564Sdim return (set_errno(error)); 88254721Semaste } 89314564Sdim return (0); 90254721Semaste} 91314564Sdim 92314564Sdim/* 93314564Sdim * File-descriptor based version of 'chdir'. 94314564Sdim */ 95254721Semasteint 96254721Semastefchdir(int fd) 97254721Semaste{ 98254721Semaste vnode_t *vp; 99296417Sdim file_t *fp; 100 int error; 101 102 if ((fp = getf(fd)) == NULL) 103 return (set_errno(EBADF)); 104 vp = fp->f_vnode; 105 VN_HOLD(vp); 106 releasef(fd); 107 error = chdirec(vp, 0, 0); 108 if (error) 109 return (set_errno(error)); 110 return (0); 111} 112 113/* 114 * Change notion of root ("/") directory. 115 */ 116int 117chroot(char *fname) 118{ 119 vnode_t *vp; 120 int error; 121 int estale_retry = 0; 122 123lookup: 124 if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) { 125 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 126 goto lookup; 127 return (set_errno(error)); 128 } 129 130 error = chdirec(vp, 1, 1); 131 if (error) { 132 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 133 goto lookup; 134 return (set_errno(error)); 135 } 136 return (0); 137} 138 139/* 140 * ++++++++++++++++++++++++ 141 * ++ SunOS4.1 Buyback ++ 142 * ++++++++++++++++++++++++ 143 * Change root directory with a user given fd 144 */ 145int 146fchroot(int fd) 147{ 148 vnode_t *vp; 149 file_t *fp; 150 int error; 151 152 if ((fp = getf(fd)) == NULL) 153 return (set_errno(EBADF)); 154 vp = fp->f_vnode; 155 VN_HOLD(vp); 156 releasef(fd); 157 error = chdirec(vp, 1, 0); 158 if (error) 159 return (set_errno(error)); 160 return (0); 161} 162 163static int 164chdirec(vnode_t *vp, int ischroot, int do_traverse) 165{ 166 int error; 167 vnode_t *oldvp; 168 proc_t *pp = curproc; 169 vnode_t **vpp; 170 refstr_t *cwd; 171 int newcwd = 1; 172 173 if (vp->v_type != VDIR) { 174 error = ENOTDIR; 175 goto bad; 176 } 177 if (error = VOP_ACCESS(vp, VEXEC, 0, CRED(), NULL)) 178 goto bad; 179 180 /* 181 * The VOP_ACCESS() may have covered 'vp' with a new filesystem, 182 * if 'vp' is an autoFS vnode. Traverse the mountpoint so 183 * that we don't end up with a covered current directory. 184 */ 185 if (vn_mountedvfs(vp) != NULL && do_traverse) { 186 if (error = traverse(&vp)) 187 goto bad; 188 } 189 190 /* 191 * Special chroot semantics: chroot is allowed if privileged 192 * or if the target is really a loopback mount of the root (or 193 * root of the zone) as determined by comparing dev and inode 194 * numbers 195 */ 196 if (ischroot) { 197 struct vattr tattr; 198 struct vattr rattr; 199 vnode_t *zonevp = curproc->p_zone->zone_rootvp; 200 201 tattr.va_mask = AT_FSID|AT_NODEID; 202 if (error = VOP_GETATTR(vp, &tattr, 0, CRED(), NULL)) 203 goto bad; 204 205 rattr.va_mask = AT_FSID|AT_NODEID; 206 if (error = VOP_GETATTR(zonevp, &rattr, 0, CRED(), NULL)) 207 goto bad; 208 209 if ((tattr.va_fsid != rattr.va_fsid || 210 tattr.va_nodeid != rattr.va_nodeid) && 211 (error = secpolicy_chroot(CRED())) != 0) 212 goto bad; 213 214 vpp = &PTOU(pp)->u_rdir; 215 } else { 216 vpp = &PTOU(pp)->u_cdir; 217 } 218 219 if (audit_active) /* update abs cwd/root path see c2audit.c */ 220 audit_chdirec(vp, vpp); 221 222 mutex_enter(&pp->p_lock); 223 /* 224 * This bit of logic prevents us from overwriting u_cwd if we are 225 * changing to the same directory. We set the cwd to NULL so that we 226 * don't try to do the lookup on the next call to getcwd(). 227 */ 228 if (!ischroot && *vpp != NULL && vp != NULL && VN_CMP(*vpp, vp)) 229 newcwd = 0; 230 231 oldvp = *vpp; 232 *vpp = vp; 233 if ((cwd = PTOU(pp)->u_cwd) != NULL && newcwd) 234 PTOU(pp)->u_cwd = NULL; 235 mutex_exit(&pp->p_lock); 236 237 if (cwd && newcwd) 238 refstr_rele(cwd); 239 if (oldvp) 240 VN_RELE(oldvp); 241 return (0); 242 243bad: 244 VN_RELE(vp); 245 return (error); 246} 247