788 lines
21 KiB
C
788 lines
21 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94
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* $FreeBSD$
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*/
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#include "opt_ktrace.h"
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#include "opt_mac.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mac.h>
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#include <sys/mutex.h>
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#include <sys/namei.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/filedesc.h>
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#include <sys/proc.h>
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#ifdef KTRACE
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#include <sys/ktrace.h>
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#endif
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#include <vm/uma.h>
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/*
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* Allocation zone for namei
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*/
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uma_zone_t namei_zone;
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static void
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nameiinit(void *dummy __unused)
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{
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namei_zone = uma_zcreate("NAMEI", MAXPATHLEN, NULL, NULL, NULL, NULL,
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UMA_ALIGN_PTR, 0);
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}
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SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL)
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/*
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* Convert a pathname into a pointer to a locked inode.
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*
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* The FOLLOW flag is set when symbolic links are to be followed
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* when they occur at the end of the name translation process.
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* Symbolic links are always followed for all other pathname
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* components other than the last.
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*
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* The segflg defines whether the name is to be copied from user
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* space or kernel space.
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*
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* Overall outline of namei:
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*
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* copy in name
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* get starting directory
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* while (!done && !error) {
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* call lookup to search path.
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* if symbolic link, massage name in buffer and continue
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* }
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*/
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int
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namei(ndp)
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register struct nameidata *ndp;
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{
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register struct filedesc *fdp; /* pointer to file descriptor state */
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register char *cp; /* pointer into pathname argument */
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register struct vnode *dp; /* the directory we are searching */
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struct iovec aiov; /* uio for reading symbolic links */
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struct uio auio;
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int error, linklen;
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struct componentname *cnp = &ndp->ni_cnd;
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struct thread *td = cnp->cn_thread;
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struct proc *p = td->td_proc;
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ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_thread->td_ucred;
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KASSERT(cnp->cn_cred && p, ("namei: bad cred/proc"));
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KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0,
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("namei: nameiop contaminated with flags"));
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KASSERT((cnp->cn_flags & OPMASK) == 0,
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("namei: flags contaminated with nameiops"));
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fdp = p->p_fd;
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/*
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* Get a buffer for the name to be translated, and copy the
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* name into the buffer.
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*/
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if ((cnp->cn_flags & HASBUF) == 0)
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cnp->cn_pnbuf = uma_zalloc(namei_zone, 0);
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if (ndp->ni_segflg == UIO_SYSSPACE)
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error = copystr(ndp->ni_dirp, cnp->cn_pnbuf,
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MAXPATHLEN, (size_t *)&ndp->ni_pathlen);
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else
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error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
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MAXPATHLEN, (size_t *)&ndp->ni_pathlen);
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/*
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* Don't allow empty pathnames.
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*/
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if (!error && *cnp->cn_pnbuf == '\0')
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error = ENOENT;
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if (error) {
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uma_zfree(namei_zone, cnp->cn_pnbuf);
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#ifdef DIAGNOSTIC
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cnp->cn_pnbuf = NULL;
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cnp->cn_nameptr = NULL;
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#endif
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ndp->ni_vp = NULL;
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return (error);
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}
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ndp->ni_loopcnt = 0;
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_NAMEI)) {
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KASSERT(cnp->cn_thread == curthread,
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("namei not using curthread"));
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ktrnamei(cnp->cn_pnbuf);
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}
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#endif
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/*
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* Get starting point for the translation.
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*/
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FILEDESC_LOCK(fdp);
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ndp->ni_rootdir = fdp->fd_rdir;
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ndp->ni_topdir = fdp->fd_jdir;
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dp = fdp->fd_cdir;
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VREF(dp);
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FILEDESC_UNLOCK(fdp);
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for (;;) {
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/*
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* Check if root directory should replace current directory.
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* Done at start of translation and after symbolic link.
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*/
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cnp->cn_nameptr = cnp->cn_pnbuf;
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if (*(cnp->cn_nameptr) == '/') {
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vrele(dp);
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while (*(cnp->cn_nameptr) == '/') {
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cnp->cn_nameptr++;
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ndp->ni_pathlen--;
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}
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dp = ndp->ni_rootdir;
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VREF(dp);
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}
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ndp->ni_startdir = dp;
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error = lookup(ndp);
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if (error) {
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uma_zfree(namei_zone, cnp->cn_pnbuf);
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#ifdef DIAGNOSTIC
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cnp->cn_pnbuf = NULL;
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cnp->cn_nameptr = NULL;
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#endif
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return (error);
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}
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/*
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* Check for symbolic link
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*/
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if ((cnp->cn_flags & ISSYMLINK) == 0) {
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if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) {
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uma_zfree(namei_zone, cnp->cn_pnbuf);
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#ifdef DIAGNOSTIC
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cnp->cn_pnbuf = NULL;
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cnp->cn_nameptr = NULL;
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#endif
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} else
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cnp->cn_flags |= HASBUF;
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if (vn_canvmio(ndp->ni_vp) == TRUE &&
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(cnp->cn_nameiop != DELETE) &&
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((cnp->cn_flags & (NOOBJ|LOCKLEAF)) ==
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LOCKLEAF))
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vfs_object_create(ndp->ni_vp, td,
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ndp->ni_cnd.cn_cred);
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return (0);
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}
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if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1)
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VOP_UNLOCK(ndp->ni_dvp, 0, td);
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if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
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error = ELOOP;
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break;
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}
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#ifdef MAC
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if ((cnp->cn_flags & NOMACCHECK) == 0) {
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error = mac_check_vnode_readlink(td->td_ucred,
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ndp->ni_vp);
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if (error)
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break;
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}
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#endif
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if (ndp->ni_pathlen > 1)
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cp = uma_zalloc(namei_zone, 0);
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else
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cp = cnp->cn_pnbuf;
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aiov.iov_base = cp;
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aiov.iov_len = MAXPATHLEN;
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auio.uio_iov = &aiov;
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auio.uio_iovcnt = 1;
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auio.uio_offset = 0;
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auio.uio_rw = UIO_READ;
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auio.uio_segflg = UIO_SYSSPACE;
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auio.uio_td = (struct thread *)0;
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auio.uio_resid = MAXPATHLEN;
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error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
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if (error) {
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if (ndp->ni_pathlen > 1)
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uma_zfree(namei_zone, cp);
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break;
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}
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linklen = MAXPATHLEN - auio.uio_resid;
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if (linklen == 0) {
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if (ndp->ni_pathlen > 1)
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uma_zfree(namei_zone, cp);
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error = ENOENT;
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break;
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}
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if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
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if (ndp->ni_pathlen > 1)
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uma_zfree(namei_zone, cp);
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error = ENAMETOOLONG;
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break;
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}
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if (ndp->ni_pathlen > 1) {
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bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
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uma_zfree(namei_zone, cnp->cn_pnbuf);
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cnp->cn_pnbuf = cp;
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} else
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cnp->cn_pnbuf[linklen] = '\0';
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ndp->ni_pathlen += linklen;
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vput(ndp->ni_vp);
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dp = ndp->ni_dvp;
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}
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uma_zfree(namei_zone, cnp->cn_pnbuf);
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#ifdef DIAGNOSTIC
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cnp->cn_pnbuf = NULL;
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cnp->cn_nameptr = NULL;
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#endif
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vrele(ndp->ni_dvp);
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vput(ndp->ni_vp);
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ndp->ni_vp = NULL;
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return (error);
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}
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/*
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* Search a pathname.
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* This is a very central and rather complicated routine.
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*
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* The pathname is pointed to by ni_ptr and is of length ni_pathlen.
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* The starting directory is taken from ni_startdir. The pathname is
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* descended until done, or a symbolic link is encountered. The variable
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* ni_more is clear if the path is completed; it is set to one if a
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* symbolic link needing interpretation is encountered.
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*
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* The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
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* whether the name is to be looked up, created, renamed, or deleted.
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* When CREATE, RENAME, or DELETE is specified, information usable in
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* creating, renaming, or deleting a directory entry may be calculated.
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* If flag has LOCKPARENT or'ed into it, the parent directory is returned
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* locked. If flag has WANTPARENT or'ed into it, the parent directory is
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* returned unlocked. Otherwise the parent directory is not returned. If
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* the target of the pathname exists and LOCKLEAF is or'ed into the flag
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* the target is returned locked, otherwise it is returned unlocked.
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* When creating or renaming and LOCKPARENT is specified, the target may not
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* be ".". When deleting and LOCKPARENT is specified, the target may be ".".
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*
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* Overall outline of lookup:
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*
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* dirloop:
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* identify next component of name at ndp->ni_ptr
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* handle degenerate case where name is null string
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* if .. and crossing mount points and on mounted filesys, find parent
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* call VOP_LOOKUP routine for next component name
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* directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
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* component vnode returned in ni_vp (if it exists), locked.
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* if result vnode is mounted on and crossing mount points,
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* find mounted on vnode
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* if more components of name, do next level at dirloop
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* return the answer in ni_vp, locked if LOCKLEAF set
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* if LOCKPARENT set, return locked parent in ni_dvp
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* if WANTPARENT set, return unlocked parent in ni_dvp
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*/
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int
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lookup(ndp)
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register struct nameidata *ndp;
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{
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register char *cp; /* pointer into pathname argument */
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register struct vnode *dp = 0; /* the directory we are searching */
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struct vnode *tdp; /* saved dp */
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struct mount *mp; /* mount table entry */
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int docache; /* == 0 do not cache last component */
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int wantparent; /* 1 => wantparent or lockparent flag */
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int rdonly; /* lookup read-only flag bit */
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int trailing_slash;
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int error = 0;
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int dpunlocked = 0; /* dp has already been unlocked */
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struct componentname *cnp = &ndp->ni_cnd;
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struct thread *td = cnp->cn_thread;
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|
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/*
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* Setup: break out flag bits into variables.
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*/
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wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
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docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
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if (cnp->cn_nameiop == DELETE ||
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(wantparent && cnp->cn_nameiop != CREATE &&
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cnp->cn_nameiop != LOOKUP))
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docache = 0;
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rdonly = cnp->cn_flags & RDONLY;
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ndp->ni_dvp = NULL;
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cnp->cn_flags &= ~ISSYMLINK;
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dp = ndp->ni_startdir;
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ndp->ni_startdir = NULLVP;
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vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td);
|
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dirloop:
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/*
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* Search a new directory.
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*
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* The last component of the filename is left accessible via
|
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* cnp->cn_nameptr for callers that need the name. Callers needing
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* the name set the SAVENAME flag. When done, they assume
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* responsibility for freeing the pathname buffer.
|
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*/
|
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cnp->cn_consume = 0;
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for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++)
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continue;
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cnp->cn_namelen = cp - cnp->cn_nameptr;
|
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if (cnp->cn_namelen > NAME_MAX) {
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error = ENAMETOOLONG;
|
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goto bad;
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}
|
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#ifdef NAMEI_DIAGNOSTIC
|
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{ char c = *cp;
|
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*cp = '\0';
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printf("{%s}: ", cnp->cn_nameptr);
|
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*cp = c; }
|
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#endif
|
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ndp->ni_pathlen -= cnp->cn_namelen;
|
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ndp->ni_next = cp;
|
|
|
|
/*
|
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* Replace multiple slashes by a single slash and trailing slashes
|
|
* by a null. This must be done before VOP_LOOKUP() because some
|
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* fs's don't know about trailing slashes. Remember if there were
|
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* trailing slashes to handle symlinks, existing non-directories
|
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* and non-existing files that won't be directories specially later.
|
|
*/
|
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trailing_slash = 0;
|
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while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) {
|
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cp++;
|
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ndp->ni_pathlen--;
|
|
if (*cp == '\0') {
|
|
trailing_slash = 1;
|
|
*ndp->ni_next = '\0'; /* XXX for direnter() ... */
|
|
}
|
|
}
|
|
ndp->ni_next = cp;
|
|
|
|
cnp->cn_flags |= MAKEENTRY;
|
|
if (*cp == '\0' && docache == 0)
|
|
cnp->cn_flags &= ~MAKEENTRY;
|
|
if (cnp->cn_namelen == 2 &&
|
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cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
|
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cnp->cn_flags |= ISDOTDOT;
|
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else
|
|
cnp->cn_flags &= ~ISDOTDOT;
|
|
if (*ndp->ni_next == 0)
|
|
cnp->cn_flags |= ISLASTCN;
|
|
else
|
|
cnp->cn_flags &= ~ISLASTCN;
|
|
|
|
|
|
/*
|
|
* Check for degenerate name (e.g. / or "")
|
|
* which is a way of talking about a directory,
|
|
* e.g. like "/." or ".".
|
|
*/
|
|
if (cnp->cn_nameptr[0] == '\0') {
|
|
if (dp->v_type != VDIR) {
|
|
error = ENOTDIR;
|
|
goto bad;
|
|
}
|
|
if (cnp->cn_nameiop != LOOKUP) {
|
|
error = EISDIR;
|
|
goto bad;
|
|
}
|
|
if (wantparent) {
|
|
ndp->ni_dvp = dp;
|
|
VREF(dp);
|
|
}
|
|
ndp->ni_vp = dp;
|
|
if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF)))
|
|
VOP_UNLOCK(dp, 0, td);
|
|
/* XXX This should probably move to the top of function. */
|
|
if (cnp->cn_flags & SAVESTART)
|
|
panic("lookup: SAVESTART");
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Handle "..": two special cases.
|
|
* 1. If at root directory (e.g. after chroot)
|
|
* or at absolute root directory
|
|
* then ignore it so can't get out.
|
|
* 2. If this vnode is the root of a mounted
|
|
* filesystem, then replace it with the
|
|
* vnode which was mounted on so we take the
|
|
* .. in the other filesystem.
|
|
* 3. If the vnode is the top directory of
|
|
* the jail or chroot, don't let them out.
|
|
*/
|
|
if (cnp->cn_flags & ISDOTDOT) {
|
|
for (;;) {
|
|
if (dp == ndp->ni_rootdir ||
|
|
dp == ndp->ni_topdir ||
|
|
dp == rootvnode) {
|
|
ndp->ni_dvp = dp;
|
|
ndp->ni_vp = dp;
|
|
VREF(dp);
|
|
goto nextname;
|
|
}
|
|
if ((dp->v_vflag & VV_ROOT) == 0 ||
|
|
(cnp->cn_flags & NOCROSSMOUNT))
|
|
break;
|
|
if (dp->v_mount == NULL) { /* forced unmount */
|
|
error = EBADF;
|
|
goto bad;
|
|
}
|
|
tdp = dp;
|
|
dp = dp->v_mount->mnt_vnodecovered;
|
|
vput(tdp);
|
|
VREF(dp);
|
|
vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We now have a segment name to search for, and a directory to search.
|
|
*/
|
|
unionlookup:
|
|
#ifdef MAC
|
|
if ((cnp->cn_flags & NOMACCHECK) == 0) {
|
|
error = mac_check_vnode_lookup(td->td_ucred, dp, cnp);
|
|
if (error)
|
|
goto bad;
|
|
}
|
|
#endif
|
|
ndp->ni_dvp = dp;
|
|
ndp->ni_vp = NULL;
|
|
cnp->cn_flags &= ~PDIRUNLOCK;
|
|
ASSERT_VOP_LOCKED(dp, "lookup");
|
|
if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) {
|
|
KASSERT(ndp->ni_vp == NULL, ("leaf should be empty"));
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
printf("not found\n");
|
|
#endif
|
|
if ((error == ENOENT) &&
|
|
(dp->v_vflag & VV_ROOT) && (dp->v_mount != NULL) &&
|
|
(dp->v_mount->mnt_flag & MNT_UNION)) {
|
|
tdp = dp;
|
|
dp = dp->v_mount->mnt_vnodecovered;
|
|
if (cnp->cn_flags & PDIRUNLOCK)
|
|
vrele(tdp);
|
|
else
|
|
vput(tdp);
|
|
VREF(dp);
|
|
vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td);
|
|
goto unionlookup;
|
|
}
|
|
|
|
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;
|
|
}
|
|
if (*cp == '\0' && trailing_slash &&
|
|
!(cnp->cn_flags & WILLBEDIR)) {
|
|
error = ENOENT;
|
|
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.
|
|
*/
|
|
if (cnp->cn_flags & SAVESTART) {
|
|
ndp->ni_startdir = ndp->ni_dvp;
|
|
VREF(ndp->ni_startdir);
|
|
}
|
|
return (0);
|
|
}
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
printf("found\n");
|
|
#endif
|
|
|
|
ASSERT_VOP_LOCKED(ndp->ni_vp, "lookup");
|
|
|
|
/*
|
|
* Take into account any additional components consumed by
|
|
* the underlying filesystem.
|
|
*/
|
|
if (cnp->cn_consume > 0) {
|
|
cnp->cn_nameptr += cnp->cn_consume;
|
|
ndp->ni_next += cnp->cn_consume;
|
|
ndp->ni_pathlen -= cnp->cn_consume;
|
|
cnp->cn_consume = 0;
|
|
}
|
|
|
|
dp = ndp->ni_vp;
|
|
|
|
/*
|
|
* Check to see if the vnode has been mounted on;
|
|
* if so find the root of the mounted filesystem.
|
|
*/
|
|
while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
|
|
(cnp->cn_flags & NOCROSSMOUNT) == 0) {
|
|
if (vfs_busy(mp, 0, 0, td))
|
|
continue;
|
|
VOP_UNLOCK(dp, 0, td);
|
|
error = VFS_ROOT(mp, &tdp);
|
|
vfs_unbusy(mp, td);
|
|
if (error) {
|
|
dpunlocked = 1;
|
|
goto bad2;
|
|
}
|
|
vrele(dp);
|
|
ndp->ni_vp = dp = tdp;
|
|
}
|
|
|
|
/*
|
|
* Check for symbolic link
|
|
*/
|
|
if ((dp->v_type == VLNK) &&
|
|
((cnp->cn_flags & FOLLOW) || trailing_slash ||
|
|
*ndp->ni_next == '/')) {
|
|
cnp->cn_flags |= ISSYMLINK;
|
|
if (dp->v_mount == NULL) {
|
|
/* We can't know whether the directory was mounted with
|
|
* NOSYMFOLLOW, so we can't follow safely. */
|
|
error = EBADF;
|
|
goto bad2;
|
|
}
|
|
if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) {
|
|
error = EACCES;
|
|
goto bad2;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Check for bogus trailing slashes.
|
|
*/
|
|
if (trailing_slash && dp->v_type != VDIR) {
|
|
error = ENOTDIR;
|
|
goto bad2;
|
|
}
|
|
|
|
nextname:
|
|
/*
|
|
* Not a symbolic link. If more pathname,
|
|
* continue at next component, else return.
|
|
*/
|
|
if (*ndp->ni_next == '/') {
|
|
cnp->cn_nameptr = ndp->ni_next;
|
|
while (*cnp->cn_nameptr == '/') {
|
|
cnp->cn_nameptr++;
|
|
ndp->ni_pathlen--;
|
|
}
|
|
if (ndp->ni_dvp != ndp->ni_vp)
|
|
ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "lookup");
|
|
vrele(ndp->ni_dvp);
|
|
goto dirloop;
|
|
}
|
|
/*
|
|
* Disallow directory write attempts on read-only filesystems.
|
|
*/
|
|
if (rdonly &&
|
|
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
|
|
error = EROFS;
|
|
goto bad2;
|
|
}
|
|
if (cnp->cn_flags & SAVESTART) {
|
|
ndp->ni_startdir = ndp->ni_dvp;
|
|
VREF(ndp->ni_startdir);
|
|
}
|
|
if (!wantparent)
|
|
vrele(ndp->ni_dvp);
|
|
|
|
if ((cnp->cn_flags & LOCKLEAF) == 0)
|
|
VOP_UNLOCK(dp, 0, td);
|
|
return (0);
|
|
|
|
bad2:
|
|
if ((cnp->cn_flags & (LOCKPARENT | PDIRUNLOCK)) == LOCKPARENT &&
|
|
*ndp->ni_next == '\0')
|
|
VOP_UNLOCK(ndp->ni_dvp, 0, td);
|
|
vrele(ndp->ni_dvp);
|
|
bad:
|
|
if (dpunlocked)
|
|
vrele(dp);
|
|
else
|
|
vput(dp);
|
|
ndp->ni_vp = NULL;
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* relookup - lookup a path name component
|
|
* Used by lookup to re-aquire things.
|
|
*/
|
|
int
|
|
relookup(dvp, vpp, cnp)
|
|
struct vnode *dvp, **vpp;
|
|
struct componentname *cnp;
|
|
{
|
|
struct thread *td = cnp->cn_thread;
|
|
struct vnode *dp = 0; /* the directory we are searching */
|
|
int docache; /* == 0 do not cache last component */
|
|
int wantparent; /* 1 => wantparent or lockparent flag */
|
|
int rdonly; /* lookup read-only flag bit */
|
|
int error = 0;
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
int newhash; /* DEBUG: check name hash */
|
|
char *cp; /* DEBUG: check name ptr/len */
|
|
#endif
|
|
|
|
/*
|
|
* Setup: break out flag bits into variables.
|
|
*/
|
|
wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
|
|
docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
|
|
if (cnp->cn_nameiop == DELETE ||
|
|
(wantparent && cnp->cn_nameiop != CREATE))
|
|
docache = 0;
|
|
rdonly = cnp->cn_flags & RDONLY;
|
|
cnp->cn_flags &= ~ISSYMLINK;
|
|
dp = dvp;
|
|
vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td);
|
|
|
|
/* dirloop: */
|
|
/*
|
|
* Search a new directory.
|
|
*
|
|
* The last component of the filename is left accessible via
|
|
* cnp->cn_nameptr for callers that need the name. Callers needing
|
|
* the name set the SAVENAME flag. When done, they assume
|
|
* responsibility for freeing the pathname buffer.
|
|
*/
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
if (cnp->cn_namelen != cp - cnp->cn_nameptr)
|
|
panic ("relookup: bad len");
|
|
if (*cp != 0)
|
|
panic("relookup: not last component");
|
|
printf("{%s}: ", cnp->cn_nameptr);
|
|
#endif
|
|
|
|
/*
|
|
* Check for degenerate name (e.g. / or "")
|
|
* which is a way of talking about a directory,
|
|
* e.g. like "/." or ".".
|
|
*/
|
|
if (cnp->cn_nameptr[0] == '\0') {
|
|
if (cnp->cn_nameiop != LOOKUP || wantparent) {
|
|
error = EISDIR;
|
|
goto bad;
|
|
}
|
|
if (dp->v_type != VDIR) {
|
|
error = ENOTDIR;
|
|
goto bad;
|
|
}
|
|
if (!(cnp->cn_flags & LOCKLEAF))
|
|
VOP_UNLOCK(dp, 0, td);
|
|
*vpp = dp;
|
|
/* XXX This should probably move to the top of function. */
|
|
if (cnp->cn_flags & SAVESTART)
|
|
panic("lookup: SAVESTART");
|
|
return (0);
|
|
}
|
|
|
|
if (cnp->cn_flags & ISDOTDOT)
|
|
panic ("relookup: lookup on dot-dot");
|
|
|
|
/*
|
|
* We now have a segment name to search for, and a directory to search.
|
|
*/
|
|
if ((error = VOP_LOOKUP(dp, 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;
|
|
}
|
|
/* ASSERT(dvp == ndp->ni_startdir) */
|
|
if (cnp->cn_flags & SAVESTART)
|
|
VREF(dvp);
|
|
/*
|
|
* 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);
|
|
}
|
|
dp = *vpp;
|
|
|
|
/*
|
|
* Check for symbolic link
|
|
*/
|
|
KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW),
|
|
("relookup: symlink found.\n"));
|
|
|
|
/*
|
|
* Disallow directory write attempts on read-only filesystems.
|
|
*/
|
|
if (rdonly &&
|
|
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
|
|
error = EROFS;
|
|
goto bad2;
|
|
}
|
|
/* ASSERT(dvp == ndp->ni_startdir) */
|
|
if (cnp->cn_flags & SAVESTART)
|
|
VREF(dvp);
|
|
|
|
if (!wantparent)
|
|
vrele(dvp);
|
|
|
|
if (vn_canvmio(dp) == TRUE &&
|
|
((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == LOCKLEAF))
|
|
vfs_object_create(dp, td, cnp->cn_cred);
|
|
|
|
if ((cnp->cn_flags & LOCKLEAF) == 0)
|
|
VOP_UNLOCK(dp, 0, td);
|
|
return (0);
|
|
|
|
bad2:
|
|
if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
|
|
VOP_UNLOCK(dvp, 0, td);
|
|
vrele(dvp);
|
|
bad:
|
|
vput(dp);
|
|
*vpp = NULL;
|
|
return (error);
|
|
}
|