/* * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94 * $FreeBSD: src/sys/kern/vfs_lookup.c,v 1.38.2.3 2001/08/31 19:36:49 dillon Exp $ */ #include "opt_ktrace.h" #include #include #include #include #include #include #include #include #include #ifdef KTRACE #include #endif #include int varsym_enable = 0; SYSCTL_INT(_vfs, OID_AUTO, varsym_enable, CTLFLAG_RW, &varsym_enable, 0, "Enable Variant Symlinks"); /* * OLD API FUNCTION * * Relookup a path name component. This function is only used by the * old API *_rename() code under very specific conditions. CNP_LOCKPARENT * must be set in the cnp. dvp must be unlocked on entry and will be left * unlocked if an error occurs. * * The returned *vpp will be NULL if an error occurs. Note that no error * will occur (error == 0) for CREATE requests on a non-existant target, but * *vpp will be NULL in that case. Both dvp and *vpp (if not NULL) will be * locked in the no-error case. No additional references are made to dvp, * only the locking state changes. */ int relookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp) { int rdonly; /* lookup read-only flag bit */ int error = 0; /* * Setup: break out flag bits into variables. */ KKASSERT(cnp->cn_flags & CNP_LOCKPARENT); KKASSERT(cnp->cn_flags & CNP_PDIRUNLOCK); vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY); cnp->cn_flags &= ~CNP_PDIRUNLOCK; *vpp = NULL; rdonly = cnp->cn_flags & CNP_RDONLY; /* * Search a new directory. */ /* * Degenerate lookups (e.g. "/", "..", derived from "/.", etc) * are not allowed. */ if (cnp->cn_nameptr[0] == '\0') { error = EISDIR; goto bad; } if (cnp->cn_flags & CNP_ISDOTDOT) panic ("relookup: lookup on dot-dot"); /* * We now have a segment name to search for, and a directory to search. */ if ((error = VOP_OLD_LOOKUP(dvp, vpp, cnp)) != 0) { KASSERT(*vpp == NULL, ("leaf should be empty")); if (error != EJUSTRETURN) goto bad; /* * If creating and at end of pathname, then can consider * allowing file to be created. */ if (rdonly) { error = EROFS; goto bad; } /* * We return with ni_vp NULL to indicate that the entry * doesn't currently exist, leaving a pointer to the * (possibly locked) directory inode in ndp->ni_dvp. */ return (0); } /* * Check for symbolic link */ KASSERT((*vpp)->v_type != VLNK || !(cnp->cn_flags & CNP_FOLLOW), ("relookup: symlink found.")); /* * Disallow directory write attempts on read-only file systems. */ if (rdonly && (cnp->cn_nameiop == NAMEI_DELETE || cnp->cn_nameiop == NAMEI_RENAME)) { error = EROFS; goto bad; } KKASSERT((cnp->cn_flags & CNP_PDIRUNLOCK) == 0); return (0); bad: if ((cnp->cn_flags & CNP_PDIRUNLOCK) == 0) { cnp->cn_flags |= CNP_PDIRUNLOCK; vn_unlock(dvp); } if (*vpp) { vput(*vpp); *vpp = NULL; } return (error); }