vfs_lookup.c revision 42453
11541Srgrimes/*
21541Srgrimes * Copyright (c) 1982, 1986, 1989, 1993
31541Srgrimes *	The Regents of the University of California.  All rights reserved.
41541Srgrimes * (c) UNIX System Laboratories, Inc.
51541Srgrimes * All or some portions of this file are derived from material licensed
61541Srgrimes * to the University of California by American Telephone and Telegraph
71541Srgrimes * Co. or Unix System Laboratories, Inc. and are reproduced herein with
81541Srgrimes * the permission of UNIX System Laboratories, Inc.
91541Srgrimes *
101541Srgrimes * Redistribution and use in source and binary forms, with or without
111541Srgrimes * modification, are permitted provided that the following conditions
121541Srgrimes * are met:
131541Srgrimes * 1. Redistributions of source code must retain the above copyright
141541Srgrimes *    notice, this list of conditions and the following disclaimer.
151541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright
161541Srgrimes *    notice, this list of conditions and the following disclaimer in the
171541Srgrimes *    documentation and/or other materials provided with the distribution.
181541Srgrimes * 3. All advertising materials mentioning features or use of this software
191541Srgrimes *    must display the following acknowledgement:
201541Srgrimes *	This product includes software developed by the University of
211541Srgrimes *	California, Berkeley and its contributors.
221541Srgrimes * 4. Neither the name of the University nor the names of its contributors
231541Srgrimes *    may be used to endorse or promote products derived from this software
241541Srgrimes *    without specific prior written permission.
251541Srgrimes *
261541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
271541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
281541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
291541Srgrimes * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
301541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
311541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
321541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
331541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
341541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
351541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
361541Srgrimes * SUCH DAMAGE.
371541Srgrimes *
381541Srgrimes *	@(#)vfs_lookup.c	8.4 (Berkeley) 2/16/94
3942453Seivind * $Id: vfs_lookup.c,v 1.30 1999/01/08 17:31:16 eivind Exp $
401541Srgrimes */
411541Srgrimes
4213203Swollman#include "opt_ktrace.h"
4313203Swollman
441541Srgrimes#include <sys/param.h>
452112Swollman#include <sys/systm.h>
461541Srgrimes#include <sys/namei.h>
471541Srgrimes#include <sys/vnode.h>
481541Srgrimes#include <sys/mount.h>
491541Srgrimes#include <sys/filedesc.h>
501541Srgrimes#include <sys/proc.h>
511541Srgrimes
521541Srgrimes#ifdef KTRACE
531541Srgrimes#include <sys/ktrace.h>
541541Srgrimes#endif
551541Srgrimes
5632011Sbde#include <vm/vm_zone.h>
5732011Sbde
581541Srgrimes/*
591541Srgrimes * Convert a pathname into a pointer to a locked inode.
601541Srgrimes *
611541Srgrimes * The FOLLOW flag is set when symbolic links are to be followed
621541Srgrimes * when they occur at the end of the name translation process.
631541Srgrimes * Symbolic links are always followed for all other pathname
641541Srgrimes * components other than the last.
651541Srgrimes *
661541Srgrimes * The segflg defines whether the name is to be copied from user
671541Srgrimes * space or kernel space.
681541Srgrimes *
691541Srgrimes * Overall outline of namei:
701541Srgrimes *
711541Srgrimes *	copy in name
721541Srgrimes *	get starting directory
731541Srgrimes *	while (!done && !error) {
741541Srgrimes *		call lookup to search path.
751541Srgrimes *		if symbolic link, massage name in buffer and continue
761541Srgrimes *	}
771541Srgrimes */
781541Srgrimesint
791541Srgrimesnamei(ndp)
801541Srgrimes	register struct nameidata *ndp;
811541Srgrimes{
821541Srgrimes	register struct filedesc *fdp;	/* pointer to file descriptor state */
831541Srgrimes	register char *cp;		/* pointer into pathname argument */
841541Srgrimes	register struct vnode *dp;	/* the directory we are searching */
851541Srgrimes	struct iovec aiov;		/* uio for reading symbolic links */
861541Srgrimes	struct uio auio;
871541Srgrimes	int error, linklen;
881541Srgrimes	struct componentname *cnp = &ndp->ni_cnd;
8922521Sdyson	struct proc *p = cnp->cn_proc;
901541Srgrimes
911541Srgrimes	ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_proc->p_ucred;
9242408Seivind	KASSERT(cnp->cn_cred && cnp->cn_proc, ("namei: bad cred/proc"));
9342408Seivind	KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0,
9442453Seivind	    ("namei: nameiop contaminated with flags"));
9542408Seivind	KASSERT((cnp->cn_flags & OPMASK) == 0,
9642453Seivind	    ("namei: flags contaminated with nameiops"));
971541Srgrimes	fdp = cnp->cn_proc->p_fd;
981541Srgrimes
991541Srgrimes	/*
1001541Srgrimes	 * Get a buffer for the name to be translated, and copy the
1011541Srgrimes	 * name into the buffer.
1021541Srgrimes	 */
1031541Srgrimes	if ((cnp->cn_flags & HASBUF) == 0)
10429653Sdyson		cnp->cn_pnbuf = zalloc(namei_zone);
1051541Srgrimes	if (ndp->ni_segflg == UIO_SYSSPACE)
1061541Srgrimes		error = copystr(ndp->ni_dirp, cnp->cn_pnbuf,
10736735Sdfr			    MAXPATHLEN, (size_t *)&ndp->ni_pathlen);
1081541Srgrimes	else
1091541Srgrimes		error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
11036735Sdfr			    MAXPATHLEN, (size_t *)&ndp->ni_pathlen);
11120069Sbde
11220069Sbde	/*
11320069Sbde	 * Don't allow empty pathnames.
11420069Sbde	 */
11520069Sbde	if (!error && *cnp->cn_pnbuf == '\0')
11620069Sbde		error = ENOENT;
11720069Sbde
1181541Srgrimes	if (error) {
11929653Sdyson		zfree(namei_zone, cnp->cn_pnbuf);
1201541Srgrimes		ndp->ni_vp = NULL;
1211541Srgrimes		return (error);
1221541Srgrimes	}
1231541Srgrimes	ndp->ni_loopcnt = 0;
1241541Srgrimes#ifdef KTRACE
1251541Srgrimes	if (KTRPOINT(cnp->cn_proc, KTR_NAMEI))
1261541Srgrimes		ktrnamei(cnp->cn_proc->p_tracep, cnp->cn_pnbuf);
1271541Srgrimes#endif
1281541Srgrimes
1291541Srgrimes	/*
1301541Srgrimes	 * Get starting point for the translation.
1311541Srgrimes	 */
13233360Sdyson	ndp->ni_rootdir = fdp->fd_rdir;
13333360Sdyson
1341541Srgrimes	dp = fdp->fd_cdir;
1351541Srgrimes	VREF(dp);
1361541Srgrimes	for (;;) {
1371541Srgrimes		/*
1381541Srgrimes		 * Check if root directory should replace current directory.
1391541Srgrimes		 * Done at start of translation and after symbolic link.
1401541Srgrimes		 */
1411541Srgrimes		cnp->cn_nameptr = cnp->cn_pnbuf;
1421541Srgrimes		if (*(cnp->cn_nameptr) == '/') {
1431541Srgrimes			vrele(dp);
1441541Srgrimes			while (*(cnp->cn_nameptr) == '/') {
1451541Srgrimes				cnp->cn_nameptr++;
1461541Srgrimes				ndp->ni_pathlen--;
1471541Srgrimes			}
1481541Srgrimes			dp = ndp->ni_rootdir;
1491541Srgrimes			VREF(dp);
1501541Srgrimes		}
1511541Srgrimes		ndp->ni_startdir = dp;
1523148Sphk		error = lookup(ndp);
1533148Sphk		if (error) {
15429653Sdyson			zfree(namei_zone, cnp->cn_pnbuf);
1551541Srgrimes			return (error);
1561541Srgrimes		}
1571541Srgrimes		/*
1581541Srgrimes		 * Check for symbolic link
1591541Srgrimes		 */
1601541Srgrimes		if ((cnp->cn_flags & ISSYMLINK) == 0) {
1611541Srgrimes			if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0)
16229653Sdyson				zfree(namei_zone, cnp->cn_pnbuf);
1631541Srgrimes			else
1641541Srgrimes				cnp->cn_flags |= HASBUF;
16532286Sdyson
16632286Sdyson			if (ndp->ni_vp && ndp->ni_vp->v_type == VREG &&
16732286Sdyson				(cnp->cn_nameiop != DELETE) &&
16842315Seivind				((cnp->cn_flags & (NOOBJ|LOCKLEAF)) ==
16942315Seivind				 LOCKLEAF))
17032286Sdyson				vfs_object_create(ndp->ni_vp,
17142315Seivind					ndp->ni_cnd.cn_proc,
17242315Seivind					ndp->ni_cnd.cn_cred);
17332286Sdyson
1741541Srgrimes			return (0);
1751541Srgrimes		}
1761541Srgrimes		if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1)
17722521Sdyson			VOP_UNLOCK(ndp->ni_dvp, 0, p);
1781541Srgrimes		if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
1791541Srgrimes			error = ELOOP;
1801541Srgrimes			break;
1811541Srgrimes		}
1821541Srgrimes		if (ndp->ni_pathlen > 1)
18329653Sdyson			cp = zalloc(namei_zone);
1841541Srgrimes		else
1851541Srgrimes			cp = cnp->cn_pnbuf;
1861541Srgrimes		aiov.iov_base = cp;
1871541Srgrimes		aiov.iov_len = MAXPATHLEN;
1881541Srgrimes		auio.uio_iov = &aiov;
1891541Srgrimes		auio.uio_iovcnt = 1;
1901541Srgrimes		auio.uio_offset = 0;
1911541Srgrimes		auio.uio_rw = UIO_READ;
1921541Srgrimes		auio.uio_segflg = UIO_SYSSPACE;
1931541Srgrimes		auio.uio_procp = (struct proc *)0;
1941541Srgrimes		auio.uio_resid = MAXPATHLEN;
1953148Sphk		error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
1963148Sphk		if (error) {
1971541Srgrimes			if (ndp->ni_pathlen > 1)
19829653Sdyson				zfree(namei_zone, cp);
1991541Srgrimes			break;
2001541Srgrimes		}
2011541Srgrimes		linklen = MAXPATHLEN - auio.uio_resid;
2021541Srgrimes		if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
2031541Srgrimes			if (ndp->ni_pathlen > 1)
20429653Sdyson				zfree(namei_zone, cp);
2051541Srgrimes			error = ENAMETOOLONG;
2061541Srgrimes			break;
2071541Srgrimes		}
2081541Srgrimes		if (ndp->ni_pathlen > 1) {
2091541Srgrimes			bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
21029653Sdyson			zfree(namei_zone, cnp->cn_pnbuf);
2111541Srgrimes			cnp->cn_pnbuf = cp;
2121541Srgrimes		} else
2131541Srgrimes			cnp->cn_pnbuf[linklen] = '\0';
2141541Srgrimes		ndp->ni_pathlen += linklen;
2151541Srgrimes		vput(ndp->ni_vp);
2161541Srgrimes		dp = ndp->ni_dvp;
2171541Srgrimes	}
21829653Sdyson	zfree(namei_zone, cnp->cn_pnbuf);
2191541Srgrimes	vrele(ndp->ni_dvp);
2201541Srgrimes	vput(ndp->ni_vp);
2211541Srgrimes	ndp->ni_vp = NULL;
2221541Srgrimes	return (error);
2231541Srgrimes}
2241541Srgrimes
2251541Srgrimes/*
2261541Srgrimes * Search a pathname.
2271541Srgrimes * This is a very central and rather complicated routine.
2281541Srgrimes *
2291541Srgrimes * The pathname is pointed to by ni_ptr and is of length ni_pathlen.
2301541Srgrimes * The starting directory is taken from ni_startdir. The pathname is
2311541Srgrimes * descended until done, or a symbolic link is encountered. The variable
2321541Srgrimes * ni_more is clear if the path is completed; it is set to one if a
2331541Srgrimes * symbolic link needing interpretation is encountered.
2341541Srgrimes *
2351541Srgrimes * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
2361541Srgrimes * whether the name is to be looked up, created, renamed, or deleted.
2371541Srgrimes * When CREATE, RENAME, or DELETE is specified, information usable in
2381541Srgrimes * creating, renaming, or deleting a directory entry may be calculated.
2391541Srgrimes * If flag has LOCKPARENT or'ed into it, the parent directory is returned
2401541Srgrimes * locked. If flag has WANTPARENT or'ed into it, the parent directory is
2411541Srgrimes * returned unlocked. Otherwise the parent directory is not returned. If
2421541Srgrimes * the target of the pathname exists and LOCKLEAF is or'ed into the flag
2431541Srgrimes * the target is returned locked, otherwise it is returned unlocked.
2441541Srgrimes * When creating or renaming and LOCKPARENT is specified, the target may not
2451541Srgrimes * be ".".  When deleting and LOCKPARENT is specified, the target may be ".".
2468876Srgrimes *
2471541Srgrimes * Overall outline of lookup:
2481541Srgrimes *
2491541Srgrimes * dirloop:
2501541Srgrimes *	identify next component of name at ndp->ni_ptr
2511541Srgrimes *	handle degenerate case where name is null string
2521541Srgrimes *	if .. and crossing mount points and on mounted filesys, find parent
2531541Srgrimes *	call VOP_LOOKUP routine for next component name
2541541Srgrimes *	    directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
2551541Srgrimes *	    component vnode returned in ni_vp (if it exists), locked.
2561541Srgrimes *	if result vnode is mounted on and crossing mount points,
2571541Srgrimes *	    find mounted on vnode
2581541Srgrimes *	if more components of name, do next level at dirloop
2591541Srgrimes *	return the answer in ni_vp, locked if LOCKLEAF set
2601541Srgrimes *	    if LOCKPARENT set, return locked parent in ni_dvp
2611541Srgrimes *	    if WANTPARENT set, return unlocked parent in ni_dvp
2621541Srgrimes */
2631541Srgrimesint
2641541Srgrimeslookup(ndp)
2651541Srgrimes	register struct nameidata *ndp;
2661541Srgrimes{
2671541Srgrimes	register char *cp;		/* pointer into pathname argument */
2681541Srgrimes	register struct vnode *dp = 0;	/* the directory we are searching */
2691541Srgrimes	struct vnode *tdp;		/* saved dp */
2701541Srgrimes	struct mount *mp;		/* mount table entry */
2711541Srgrimes	int docache;			/* == 0 do not cache last component */
2721541Srgrimes	int wantparent;			/* 1 => wantparent or lockparent flag */
2731541Srgrimes	int rdonly;			/* lookup read-only flag bit */
2749804Sbde	int trailing_slash;
2751541Srgrimes	int error = 0;
2761541Srgrimes	struct componentname *cnp = &ndp->ni_cnd;
27722521Sdyson	struct proc *p = cnp->cn_proc;
2781541Srgrimes
2791541Srgrimes	/*
2801541Srgrimes	 * Setup: break out flag bits into variables.
2811541Srgrimes	 */
2821541Srgrimes	wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
2831541Srgrimes	docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
2841541Srgrimes	if (cnp->cn_nameiop == DELETE ||
28522874Sbde	    (wantparent && cnp->cn_nameiop != CREATE &&
28622874Sbde	     cnp->cn_nameiop != LOOKUP))
2871541Srgrimes		docache = 0;
2881541Srgrimes	rdonly = cnp->cn_flags & RDONLY;
2891541Srgrimes	ndp->ni_dvp = NULL;
2901541Srgrimes	cnp->cn_flags &= ~ISSYMLINK;
2911541Srgrimes	dp = ndp->ni_startdir;
2921541Srgrimes	ndp->ni_startdir = NULLVP;
29322521Sdyson	vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
2941541Srgrimes
2951541Srgrimesdirloop:
2961541Srgrimes	/*
2971541Srgrimes	 * Search a new directory.
2981541Srgrimes	 *
2991541Srgrimes	 * The cn_hash value is for use by vfs_cache.
3001541Srgrimes	 * The last component of the filename is left accessible via
3011541Srgrimes	 * cnp->cn_nameptr for callers that need the name. Callers needing
3021541Srgrimes	 * the name set the SAVENAME flag. When done, they assume
3031541Srgrimes	 * responsibility for freeing the pathname buffer.
3041541Srgrimes	 */
3051541Srgrimes	cnp->cn_consume = 0;
3061541Srgrimes	cnp->cn_hash = 0;
3071541Srgrimes	for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++)
3081541Srgrimes		cnp->cn_hash += (unsigned char)*cp;
3091541Srgrimes	cnp->cn_namelen = cp - cnp->cn_nameptr;
3101541Srgrimes	if (cnp->cn_namelen > NAME_MAX) {
3111541Srgrimes		error = ENAMETOOLONG;
3121541Srgrimes		goto bad;
3131541Srgrimes	}
3141541Srgrimes#ifdef NAMEI_DIAGNOSTIC
3151541Srgrimes	{ char c = *cp;
3161541Srgrimes	*cp = '\0';
3171541Srgrimes	printf("{%s}: ", cnp->cn_nameptr);
3181541Srgrimes	*cp = c; }
3191541Srgrimes#endif
3201541Srgrimes	ndp->ni_pathlen -= cnp->cn_namelen;
3211541Srgrimes	ndp->ni_next = cp;
3229804Sbde
3239804Sbde	/*
3249804Sbde	 * Replace multiple slashes by a single slash and trailing slashes
3259804Sbde	 * by a null.  This must be done before VOP_LOOKUP() because some
3269804Sbde	 * fs's don't know about trailing slashes.  Remember if there were
3279804Sbde	 * trailing slashes to handle symlinks, existing non-directories
3289804Sbde	 * and non-existing files that won't be directories specially later.
3299804Sbde	 */
3309804Sbde	trailing_slash = 0;
3319804Sbde	while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) {
3329804Sbde		cp++;
3339804Sbde		ndp->ni_pathlen--;
3349804Sbde		if (*cp == '\0') {
3359804Sbde			trailing_slash = 1;
3369804Sbde			*ndp->ni_next = '\0';	/* XXX for direnter() ... */
3379804Sbde		}
3389804Sbde	}
3399804Sbde	ndp->ni_next = cp;
3409804Sbde
3411541Srgrimes	cnp->cn_flags |= MAKEENTRY;
3421541Srgrimes	if (*cp == '\0' && docache == 0)
3431541Srgrimes		cnp->cn_flags &= ~MAKEENTRY;
3441541Srgrimes	if (cnp->cn_namelen == 2 &&
3451541Srgrimes	    cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
3461541Srgrimes		cnp->cn_flags |= ISDOTDOT;
3471541Srgrimes	else
3481541Srgrimes		cnp->cn_flags &= ~ISDOTDOT;
3491541Srgrimes	if (*ndp->ni_next == 0)
3501541Srgrimes		cnp->cn_flags |= ISLASTCN;
3511541Srgrimes	else
3521541Srgrimes		cnp->cn_flags &= ~ISLASTCN;
3531541Srgrimes
3541541Srgrimes
3551541Srgrimes	/*
3561541Srgrimes	 * Check for degenerate name (e.g. / or "")
3571541Srgrimes	 * which is a way of talking about a directory,
3581541Srgrimes	 * e.g. like "/." or ".".
3591541Srgrimes	 */
3601541Srgrimes	if (cnp->cn_nameptr[0] == '\0') {
36122521Sdyson		if (dp->v_type != VDIR) {
36222521Sdyson			error = ENOTDIR;
36322521Sdyson			goto bad;
36422521Sdyson		}
3651541Srgrimes		if (cnp->cn_nameiop != LOOKUP) {
3661541Srgrimes			error = EISDIR;
3671541Srgrimes			goto bad;
3681541Srgrimes		}
3691541Srgrimes		if (wantparent) {
3701541Srgrimes			ndp->ni_dvp = dp;
3711541Srgrimes			VREF(dp);
3721541Srgrimes		}
3731541Srgrimes		ndp->ni_vp = dp;
3741541Srgrimes		if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF)))
37522521Sdyson			VOP_UNLOCK(dp, 0, p);
3761541Srgrimes		if (cnp->cn_flags & SAVESTART)
3771541Srgrimes			panic("lookup: SAVESTART");
3781541Srgrimes		return (0);
3791541Srgrimes	}
3801541Srgrimes
3811541Srgrimes	/*
3821541Srgrimes	 * Handle "..": two special cases.
3831541Srgrimes	 * 1. If at root directory (e.g. after chroot)
3841541Srgrimes	 *    or at absolute root directory
3851541Srgrimes	 *    then ignore it so can't get out.
3861541Srgrimes	 * 2. If this vnode is the root of a mounted
3871541Srgrimes	 *    filesystem, then replace it with the
3881541Srgrimes	 *    vnode which was mounted on so we take the
3891541Srgrimes	 *    .. in the other file system.
3901541Srgrimes	 */
3911541Srgrimes	if (cnp->cn_flags & ISDOTDOT) {
3921541Srgrimes		for (;;) {
3931541Srgrimes			if (dp == ndp->ni_rootdir || dp == rootvnode) {
3941541Srgrimes				ndp->ni_dvp = dp;
3951541Srgrimes				ndp->ni_vp = dp;
3961541Srgrimes				VREF(dp);
3971541Srgrimes				goto nextname;
3981541Srgrimes			}
3991541Srgrimes			if ((dp->v_flag & VROOT) == 0 ||
4001541Srgrimes			    (cnp->cn_flags & NOCROSSMOUNT))
4011541Srgrimes				break;
4021541Srgrimes			tdp = dp;
4031541Srgrimes			dp = dp->v_mount->mnt_vnodecovered;
4041541Srgrimes			vput(tdp);
4051541Srgrimes			VREF(dp);
40622521Sdyson			vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
4071541Srgrimes		}
4081541Srgrimes	}
4091541Srgrimes
4101541Srgrimes	/*
4111541Srgrimes	 * We now have a segment name to search for, and a directory to search.
4121541Srgrimes	 */
4131541Srgrimesunionlookup:
4141541Srgrimes	ndp->ni_dvp = dp;
41522521Sdyson	ndp->ni_vp = NULL;
41624624Sdfr	ASSERT_VOP_LOCKED(dp, "lookup");
41722521Sdyson	if (error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) {
41842408Seivind		KASSERT(ndp->ni_vp == NULL, ("leaf should be empty"));
4191541Srgrimes#ifdef NAMEI_DIAGNOSTIC
4201541Srgrimes		printf("not found\n");
4211541Srgrimes#endif
4221541Srgrimes		if ((error == ENOENT) &&
4231541Srgrimes		    (dp->v_flag & VROOT) &&
4241541Srgrimes		    (dp->v_mount->mnt_flag & MNT_UNION)) {
4251541Srgrimes			tdp = dp;
4261541Srgrimes			dp = dp->v_mount->mnt_vnodecovered;
4271541Srgrimes			vput(tdp);
4281541Srgrimes			VREF(dp);
42922521Sdyson			vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
4301541Srgrimes			goto unionlookup;
4311541Srgrimes		}
4321541Srgrimes
4331541Srgrimes		if (error != EJUSTRETURN)
4341541Srgrimes			goto bad;
4351541Srgrimes		/*
4361541Srgrimes		 * If creating and at end of pathname, then can consider
4371541Srgrimes		 * allowing file to be created.
4381541Srgrimes		 */
43911644Sdg		if (rdonly) {
4401541Srgrimes			error = EROFS;
4411541Srgrimes			goto bad;
4421541Srgrimes		}
4439804Sbde		if (*cp == '\0' && trailing_slash &&
4449804Sbde		     !(cnp->cn_flags & WILLBEDIR)) {
4459804Sbde			error = ENOENT;
4469804Sbde			goto bad;
4479804Sbde		}
4481541Srgrimes		/*
4491541Srgrimes		 * We return with ni_vp NULL to indicate that the entry
4501541Srgrimes		 * doesn't currently exist, leaving a pointer to the
4511541Srgrimes		 * (possibly locked) directory inode in ndp->ni_dvp.
4521541Srgrimes		 */
4531541Srgrimes		if (cnp->cn_flags & SAVESTART) {
4541541Srgrimes			ndp->ni_startdir = ndp->ni_dvp;
4551541Srgrimes			VREF(ndp->ni_startdir);
4561541Srgrimes		}
4571541Srgrimes		return (0);
4581541Srgrimes	}
4591541Srgrimes#ifdef NAMEI_DIAGNOSTIC
4601541Srgrimes	printf("found\n");
4611541Srgrimes#endif
4621541Srgrimes
46324624Sdfr	ASSERT_VOP_LOCKED(ndp->ni_vp, "lookup");
46424624Sdfr
4651541Srgrimes	/*
4661541Srgrimes	 * Take into account any additional components consumed by
4671541Srgrimes	 * the underlying filesystem.
4681541Srgrimes	 */
4691541Srgrimes	if (cnp->cn_consume > 0) {
4701541Srgrimes		cnp->cn_nameptr += cnp->cn_consume;
4711541Srgrimes		ndp->ni_next += cnp->cn_consume;
4721541Srgrimes		ndp->ni_pathlen -= cnp->cn_consume;
4731541Srgrimes		cnp->cn_consume = 0;
4741541Srgrimes	}
4751541Srgrimes
4761541Srgrimes	dp = ndp->ni_vp;
4771541Srgrimes
4781541Srgrimes	/*
4791541Srgrimes	 * Check to see if the vnode has been mounted on;
4801541Srgrimes	 * if so find the root of the mounted file system.
4811541Srgrimes	 */
4821541Srgrimes	while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
4831541Srgrimes	       (cnp->cn_flags & NOCROSSMOUNT) == 0) {
48422521Sdyson		if (vfs_busy(mp, 0, 0, p))
4851541Srgrimes			continue;
48622521Sdyson		error = VFS_ROOT(mp, &tdp);
48722521Sdyson		vfs_unbusy(mp, p);
4883148Sphk		if (error)
4891541Srgrimes			goto bad2;
4901541Srgrimes		vput(dp);
4911541Srgrimes		ndp->ni_vp = dp = tdp;
4921541Srgrimes	}
4931541Srgrimes
49410219Sdfr	/*
49510219Sdfr	 * Check for symbolic link
49610219Sdfr	 */
49710219Sdfr	if ((dp->v_type == VLNK) &&
49810219Sdfr	    ((cnp->cn_flags & FOLLOW) || trailing_slash ||
49910219Sdfr	     *ndp->ni_next == '/')) {
50010219Sdfr		cnp->cn_flags |= ISSYMLINK;
50135105Swosch		if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) {
50235105Swosch			error = EACCES;
50335105Swosch			goto bad2;
50435105Swosch		}
50510219Sdfr		return (0);
50610219Sdfr	}
50710219Sdfr
50810219Sdfr	/*
50910219Sdfr	 * Check for bogus trailing slashes.
51010219Sdfr	 */
51110219Sdfr	if (trailing_slash && dp->v_type != VDIR) {
51210219Sdfr		error = ENOTDIR;
51310219Sdfr		goto bad2;
51410219Sdfr	}
51510219Sdfr
5161541Srgrimesnextname:
5171541Srgrimes	/*
5181541Srgrimes	 * Not a symbolic link.  If more pathname,
5191541Srgrimes	 * continue at next component, else return.
5201541Srgrimes	 */
5211541Srgrimes	if (*ndp->ni_next == '/') {
5221541Srgrimes		cnp->cn_nameptr = ndp->ni_next;
5231541Srgrimes		while (*cnp->cn_nameptr == '/') {
5241541Srgrimes			cnp->cn_nameptr++;
5251541Srgrimes			ndp->ni_pathlen--;
5261541Srgrimes		}
52724624Sdfr		if (ndp->ni_dvp != ndp->ni_vp) {
52824624Sdfr		    ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "lookup");
52924624Sdfr		}
5301541Srgrimes		vrele(ndp->ni_dvp);
5311541Srgrimes		goto dirloop;
5321541Srgrimes	}
5331541Srgrimes	/*
53411644Sdg	 * Disallow directory write attempts on read-only file systems.
5351541Srgrimes	 */
53611644Sdg	if (rdonly &&
53711644Sdg	    (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
53811644Sdg		error = EROFS;
53911644Sdg		goto bad2;
5401541Srgrimes	}
5411541Srgrimes	if (cnp->cn_flags & SAVESTART) {
5421541Srgrimes		ndp->ni_startdir = ndp->ni_dvp;
5431541Srgrimes		VREF(ndp->ni_startdir);
5441541Srgrimes	}
5451541Srgrimes	if (!wantparent)
5461541Srgrimes		vrele(ndp->ni_dvp);
54732071Sdyson
5481541Srgrimes	if ((cnp->cn_flags & LOCKLEAF) == 0)
54922521Sdyson		VOP_UNLOCK(dp, 0, p);
5501541Srgrimes	return (0);
5511541Srgrimes
5521541Srgrimesbad2:
5531541Srgrimes	if ((cnp->cn_flags & LOCKPARENT) && *ndp->ni_next == '\0')
55422521Sdyson		VOP_UNLOCK(ndp->ni_dvp, 0, p);
5551541Srgrimes	vrele(ndp->ni_dvp);
5561541Srgrimesbad:
5571541Srgrimes	vput(dp);
5581541Srgrimes	ndp->ni_vp = NULL;
5591541Srgrimes	return (error);
5601541Srgrimes}
5611541Srgrimes
5623148Sphk/*
5633148Sphk * relookup - lookup a path name component
5643148Sphk *    Used by lookup to re-aquire things.
5653148Sphk */
5663148Sphkint
5673148Sphkrelookup(dvp, vpp, cnp)
5683148Sphk	struct vnode *dvp, **vpp;
5693148Sphk	struct componentname *cnp;
5703148Sphk{
57122521Sdyson	struct proc *p = cnp->cn_proc;
57222521Sdyson	struct vnode *dp = 0;		/* the directory we are searching */
5733148Sphk	int docache;			/* == 0 do not cache last component */
5743148Sphk	int wantparent;			/* 1 => wantparent or lockparent flag */
5753148Sphk	int rdonly;			/* lookup read-only flag bit */
5763148Sphk	int error = 0;
5773148Sphk#ifdef NAMEI_DIAGNOSTIC
5783148Sphk	int newhash;			/* DEBUG: check name hash */
5793148Sphk	char *cp;			/* DEBUG: check name ptr/len */
5803148Sphk#endif
5811541Srgrimes
5823148Sphk	/*
5833148Sphk	 * Setup: break out flag bits into variables.
5843148Sphk	 */
5853148Sphk	wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
5863148Sphk	docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
5873148Sphk	if (cnp->cn_nameiop == DELETE ||
5883148Sphk	    (wantparent && cnp->cn_nameiop != CREATE))
5893148Sphk		docache = 0;
5903148Sphk	rdonly = cnp->cn_flags & RDONLY;
5913148Sphk	cnp->cn_flags &= ~ISSYMLINK;
5923148Sphk	dp = dvp;
59322521Sdyson	vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, p);
5943148Sphk
5953148Sphk/* dirloop: */
5963148Sphk	/*
5973148Sphk	 * Search a new directory.
5983148Sphk	 *
5993148Sphk	 * The cn_hash value is for use by vfs_cache.
6003148Sphk	 * The last component of the filename is left accessible via
6013148Sphk	 * cnp->cn_nameptr for callers that need the name. Callers needing
6023148Sphk	 * the name set the SAVENAME flag. When done, they assume
6033148Sphk	 * responsibility for freeing the pathname buffer.
6043148Sphk	 */
6053148Sphk#ifdef NAMEI_DIAGNOSTIC
6063148Sphk	for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++)
6073148Sphk		newhash += (unsigned char)*cp;
6083148Sphk	if (newhash != cnp->cn_hash)
6093148Sphk		panic("relookup: bad hash");
6103148Sphk	if (cnp->cn_namelen != cp - cnp->cn_nameptr)
6113148Sphk		panic ("relookup: bad len");
6123148Sphk	if (*cp != 0)
6133148Sphk		panic("relookup: not last component");
6143148Sphk	printf("{%s}: ", cnp->cn_nameptr);
6153148Sphk#endif
6163148Sphk
6173148Sphk	/*
6183148Sphk	 * Check for degenerate name (e.g. / or "")
6193148Sphk	 * which is a way of talking about a directory,
6203148Sphk	 * e.g. like "/." or ".".
6213148Sphk	 */
6223148Sphk	if (cnp->cn_nameptr[0] == '\0') {
6233148Sphk		if (cnp->cn_nameiop != LOOKUP || wantparent) {
6243148Sphk			error = EISDIR;
6253148Sphk			goto bad;
6263148Sphk		}
6273148Sphk		if (dp->v_type != VDIR) {
6283148Sphk			error = ENOTDIR;
6293148Sphk			goto bad;
6303148Sphk		}
6313148Sphk		if (!(cnp->cn_flags & LOCKLEAF))
63222521Sdyson			VOP_UNLOCK(dp, 0, p);
6333148Sphk		*vpp = dp;
6343148Sphk		if (cnp->cn_flags & SAVESTART)
6353148Sphk			panic("lookup: SAVESTART");
6363148Sphk		return (0);
6373148Sphk	}
6383148Sphk
6393148Sphk	if (cnp->cn_flags & ISDOTDOT)
6403148Sphk		panic ("relookup: lookup on dot-dot");
6413148Sphk
6423148Sphk	/*
6433148Sphk	 * We now have a segment name to search for, and a directory to search.
6443148Sphk	 */
64522521Sdyson	if (error = VOP_LOOKUP(dp, vpp, cnp)) {
64642408Seivind		KASSERT(*vpp == NULL, ("leaf should be empty"));
6473148Sphk		if (error != EJUSTRETURN)
6483148Sphk			goto bad;
6493148Sphk		/*
6503148Sphk		 * If creating and at end of pathname, then can consider
6513148Sphk		 * allowing file to be created.
6523148Sphk		 */
65311644Sdg		if (rdonly) {
6543148Sphk			error = EROFS;
6553148Sphk			goto bad;
6563148Sphk		}
6573148Sphk		/* ASSERT(dvp == ndp->ni_startdir) */
6583148Sphk		if (cnp->cn_flags & SAVESTART)
6593148Sphk			VREF(dvp);
6603148Sphk		/*
6613148Sphk		 * We return with ni_vp NULL to indicate that the entry
6623148Sphk		 * doesn't currently exist, leaving a pointer to the
6633148Sphk		 * (possibly locked) directory inode in ndp->ni_dvp.
6643148Sphk		 */
6653148Sphk		return (0);
6663148Sphk	}
6673148Sphk	dp = *vpp;
6683148Sphk
6693148Sphk	/*
6703148Sphk	 * Check for symbolic link
6713148Sphk	 */
67242408Seivind	KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW),
67342453Seivind	    ("relookup: symlink found.\n"));
6743148Sphk
6753148Sphk	/*
67611644Sdg	 * Disallow directory write attempts on read-only file systems.
6773148Sphk	 */
67811644Sdg	if (rdonly &&
67911644Sdg	    (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
68011644Sdg		error = EROFS;
68111644Sdg		goto bad2;
6823148Sphk	}
6833148Sphk	/* ASSERT(dvp == ndp->ni_startdir) */
6843148Sphk	if (cnp->cn_flags & SAVESTART)
6853148Sphk		VREF(dvp);
68622521Sdyson
6873148Sphk	if (!wantparent)
6883148Sphk		vrele(dvp);
68932071Sdyson
69032286Sdyson	if (dp->v_type == VREG &&
69132286Sdyson		((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == LOCKLEAF))
69242315Seivind		vfs_object_create(dp, cnp->cn_proc, cnp->cn_cred);
69332071Sdyson
6943148Sphk	if ((cnp->cn_flags & LOCKLEAF) == 0)
69522521Sdyson		VOP_UNLOCK(dp, 0, p);
6963148Sphk	return (0);
6973148Sphk
6983148Sphkbad2:
6993148Sphk	if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
70022521Sdyson		VOP_UNLOCK(dvp, 0, p);
7013148Sphk	vrele(dvp);
7023148Sphkbad:
7033148Sphk	vput(dp);
7043148Sphk	*vpp = NULL;
7053148Sphk	return (error);
7063148Sphk}
707