1/*- 2 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD$"); 29 30#include <sys/param.h> 31#include <sys/kernel.h> 32#include <sys/systm.h> 33#include <sys/pathname.h> 34#include <sys/vfs.h> 35#include <sys/vnode.h> 36 37int 38lookupname(char *dirname, enum uio_seg seg, enum symfollow follow, 39 vnode_t **dirvpp, vnode_t **compvpp) 40{ 41 42 return (lookupnameat(dirname, seg, follow, dirvpp, compvpp, NULL)); 43} 44 45int 46lookupnameat(char *dirname, enum uio_seg seg, enum symfollow follow, 47 vnode_t **dirvpp, vnode_t **compvpp, vnode_t *startvp) 48{ 49 struct nameidata nd; 50 int error, ltype; 51 52 ASSERT(dirvpp == NULL); 53 54 vref(startvp); 55 ltype = VOP_ISLOCKED(startvp); 56 VOP_UNLOCK(startvp, 0); 57 NDINIT_ATVP(&nd, LOOKUP, LOCKLEAF | MPSAFE | follow, seg, dirname, 58 startvp, curthread); 59 error = namei(&nd); 60 *compvpp = nd.ni_vp; 61 NDFREE(&nd, NDF_ONLY_PNBUF); 62 vn_lock(startvp, ltype | LK_RETRY); 63 return (error); 64} 65 66int 67traverse(vnode_t **cvpp, int lktype) 68{ 69 vnode_t *cvp; 70 vnode_t *tvp; 71 vfs_t *vfsp; 72 int error; 73 74 cvp = *cvpp; 75 tvp = NULL; 76 77 /* 78 * If this vnode is mounted on, then we transparently indirect 79 * to the vnode which is the root of the mounted file system. 80 * Before we do this we must check that an unmount is not in 81 * progress on this vnode. 82 */ 83 84 for (;;) { 85 /* 86 * Reached the end of the mount chain? 87 */ 88 vfsp = vn_mountedvfs(cvp); 89 if (vfsp == NULL) 90 break; 91 error = vfs_busy(vfsp, 0); 92 /* 93 * tvp is NULL for *cvpp vnode, which we can't unlock. 94 */ 95 if (tvp != NULL) 96 vput(cvp); 97 else 98 vrele(cvp); 99 if (error) 100 return (error); 101 102 /* 103 * The read lock must be held across the call to VFS_ROOT() to 104 * prevent a concurrent unmount from destroying the vfs. 105 */ 106 error = VFS_ROOT(vfsp, lktype, &tvp); 107 vfs_unbusy(vfsp); 108 if (error != 0) 109 return (error); 110 cvp = tvp; 111 } 112 113 *cvpp = cvp; 114 return (0); 115} 116