vfs_lookup.c revision 144229
1139804Simp/*- 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 * 4. Neither the name of the University nor the names of its contributors 191541Srgrimes * may be used to endorse or promote products derived from this software 201541Srgrimes * without specific prior written permission. 211541Srgrimes * 221541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 231541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 241541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 251541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 261541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 271541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 281541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 291541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 301541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 311541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 321541Srgrimes * SUCH DAMAGE. 331541Srgrimes * 341541Srgrimes * @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94 351541Srgrimes */ 361541Srgrimes 37116182Sobrien#include <sys/cdefs.h> 38116182Sobrien__FBSDID("$FreeBSD: head/sys/kern/vfs_lookup.c 144229 2005-03-28 13:56:56Z jeff $"); 39116182Sobrien 4013203Swollman#include "opt_ktrace.h" 41101127Srwatson#include "opt_mac.h" 4213203Swollman 431541Srgrimes#include <sys/param.h> 442112Swollman#include <sys/systm.h> 4569664Speter#include <sys/kernel.h> 4676166Smarkm#include <sys/lock.h> 47101127Srwatson#include <sys/mac.h> 4889316Salfred#include <sys/mutex.h> 491541Srgrimes#include <sys/namei.h> 501541Srgrimes#include <sys/vnode.h> 511541Srgrimes#include <sys/mount.h> 521541Srgrimes#include <sys/filedesc.h> 531541Srgrimes#include <sys/proc.h> 54141471Sjhb#include <sys/syscallsubr.h> 551541Srgrimes#ifdef KTRACE 561541Srgrimes#include <sys/ktrace.h> 571541Srgrimes#endif 581541Srgrimes 5992751Sjeff#include <vm/uma.h> 6032011Sbde 61138345Sphk#define NAMEI_DIAGNOSTIC 1 62138345Sphk#undef NAMEI_DIAGNOSTIC 63138345Sphk 641541Srgrimes/* 6569664Speter * Allocation zone for namei 6669664Speter */ 6792751Sjeffuma_zone_t namei_zone; 6869664Speter 6969664Speterstatic void 7069664Speternameiinit(void *dummy __unused) 7169664Speter{ 7292654Sjeff namei_zone = uma_zcreate("NAMEI", MAXPATHLEN, NULL, NULL, NULL, NULL, 7392654Sjeff UMA_ALIGN_PTR, 0); 7469664Speter 7569664Speter} 7669664SpeterSYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL) 7769664Speter 7869664Speter/* 791541Srgrimes * Convert a pathname into a pointer to a locked inode. 801541Srgrimes * 811541Srgrimes * The FOLLOW flag is set when symbolic links are to be followed 821541Srgrimes * when they occur at the end of the name translation process. 831541Srgrimes * Symbolic links are always followed for all other pathname 841541Srgrimes * components other than the last. 851541Srgrimes * 861541Srgrimes * The segflg defines whether the name is to be copied from user 871541Srgrimes * space or kernel space. 881541Srgrimes * 891541Srgrimes * Overall outline of namei: 901541Srgrimes * 911541Srgrimes * copy in name 921541Srgrimes * get starting directory 931541Srgrimes * while (!done && !error) { 941541Srgrimes * call lookup to search path. 951541Srgrimes * if symbolic link, massage name in buffer and continue 961541Srgrimes * } 971541Srgrimes */ 981541Srgrimesint 991541Srgrimesnamei(ndp) 1001541Srgrimes register struct nameidata *ndp; 1011541Srgrimes{ 1021541Srgrimes register struct filedesc *fdp; /* pointer to file descriptor state */ 1031541Srgrimes register char *cp; /* pointer into pathname argument */ 1041541Srgrimes register struct vnode *dp; /* the directory we are searching */ 1051541Srgrimes struct iovec aiov; /* uio for reading symbolic links */ 1061541Srgrimes struct uio auio; 1071541Srgrimes int error, linklen; 1081541Srgrimes struct componentname *cnp = &ndp->ni_cnd; 10983366Sjulian struct thread *td = cnp->cn_thread; 11083366Sjulian struct proc *p = td->td_proc; 111140714Sjeff struct mount *mp; 112140714Sjeff int vfslocked; 1131541Srgrimes 11491419Sjhb ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_thread->td_ucred; 11583366Sjulian KASSERT(cnp->cn_cred && p, ("namei: bad cred/proc")); 11642408Seivind KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0, 11742453Seivind ("namei: nameiop contaminated with flags")); 11842408Seivind KASSERT((cnp->cn_flags & OPMASK) == 0, 11942453Seivind ("namei: flags contaminated with nameiops")); 120144048Sjeff#ifndef LOOKUP_SHARED 121144048Sjeff cnp->cn_flags &= ~LOCKSHARED; 122144048Sjeff#endif 12383366Sjulian fdp = p->p_fd; 1241541Srgrimes 1251541Srgrimes /* 1261541Srgrimes * Get a buffer for the name to be translated, and copy the 1271541Srgrimes * name into the buffer. 1281541Srgrimes */ 1291541Srgrimes if ((cnp->cn_flags & HASBUF) == 0) 130111119Simp cnp->cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK); 1311541Srgrimes if (ndp->ni_segflg == UIO_SYSSPACE) 1321541Srgrimes error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 13336735Sdfr MAXPATHLEN, (size_t *)&ndp->ni_pathlen); 1341541Srgrimes else 1351541Srgrimes error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 13636735Sdfr MAXPATHLEN, (size_t *)&ndp->ni_pathlen); 13720069Sbde 13820069Sbde /* 13920069Sbde * Don't allow empty pathnames. 14020069Sbde */ 14120069Sbde if (!error && *cnp->cn_pnbuf == '\0') 14220069Sbde error = ENOENT; 14320069Sbde 1441541Srgrimes if (error) { 14592751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 146100613Srwatson#ifdef DIAGNOSTIC 147100613Srwatson cnp->cn_pnbuf = NULL; 148100613Srwatson cnp->cn_nameptr = NULL; 149100613Srwatson#endif 1501541Srgrimes ndp->ni_vp = NULL; 1511541Srgrimes return (error); 1521541Srgrimes } 1531541Srgrimes ndp->ni_loopcnt = 0; 1541541Srgrimes#ifdef KTRACE 15597994Sjhb if (KTRPOINT(td, KTR_NAMEI)) { 15697994Sjhb KASSERT(cnp->cn_thread == curthread, 15797994Sjhb ("namei not using curthread")); 15897994Sjhb ktrnamei(cnp->cn_pnbuf); 15997994Sjhb } 1601541Srgrimes#endif 1611541Srgrimes 1621541Srgrimes /* 1631541Srgrimes * Get starting point for the translation. 1641541Srgrimes */ 16589306Salfred FILEDESC_LOCK(fdp); 16633360Sdyson ndp->ni_rootdir = fdp->fd_rdir; 16751649Sphk ndp->ni_topdir = fdp->fd_jdir; 16833360Sdyson 1691541Srgrimes dp = fdp->fd_cdir; 170140714Sjeff vfslocked = VFS_LOCK_GIANT(dp->v_mount); 1711541Srgrimes VREF(dp); 17289306Salfred FILEDESC_UNLOCK(fdp); 1731541Srgrimes for (;;) { 1741541Srgrimes /* 1751541Srgrimes * Check if root directory should replace current directory. 1761541Srgrimes * Done at start of translation and after symbolic link. 1771541Srgrimes */ 1781541Srgrimes cnp->cn_nameptr = cnp->cn_pnbuf; 1791541Srgrimes if (*(cnp->cn_nameptr) == '/') { 1801541Srgrimes vrele(dp); 181140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 1821541Srgrimes while (*(cnp->cn_nameptr) == '/') { 1831541Srgrimes cnp->cn_nameptr++; 1841541Srgrimes ndp->ni_pathlen--; 1851541Srgrimes } 1861541Srgrimes dp = ndp->ni_rootdir; 187140714Sjeff vfslocked = VFS_LOCK_GIANT(dp->v_mount); 1881541Srgrimes VREF(dp); 1891541Srgrimes } 190140714Sjeff if (vfslocked) 191140714Sjeff ndp->ni_cnd.cn_flags |= GIANTHELD; 1921541Srgrimes ndp->ni_startdir = dp; 1933148Sphk error = lookup(ndp); 1943148Sphk if (error) { 19592751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 196100613Srwatson#ifdef DIAGNOSTIC 197100613Srwatson cnp->cn_pnbuf = NULL; 198100613Srwatson cnp->cn_nameptr = NULL; 199100613Srwatson#endif 2001541Srgrimes return (error); 2011541Srgrimes } 202140714Sjeff vfslocked = (ndp->ni_cnd.cn_flags & GIANTHELD) != 0; 203140714Sjeff ndp->ni_cnd.cn_flags &= ~GIANTHELD; 2041541Srgrimes /* 2051541Srgrimes * Check for symbolic link 2061541Srgrimes */ 2071541Srgrimes if ((cnp->cn_flags & ISSYMLINK) == 0) { 208100613Srwatson if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) { 20992751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 210100613Srwatson#ifdef DIAGNOSTIC 211100613Srwatson cnp->cn_pnbuf = NULL; 212100613Srwatson cnp->cn_nameptr = NULL; 213100613Srwatson#endif 214100613Srwatson } else 2151541Srgrimes cnp->cn_flags |= HASBUF; 21632286Sdyson 217140714Sjeff if ((cnp->cn_flags & MPSAFE) == 0) { 218140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 219140714Sjeff } else if (vfslocked) 220140714Sjeff ndp->ni_cnd.cn_flags |= GIANTHELD; 2211541Srgrimes return (0); 2221541Srgrimes } 2231541Srgrimes if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1) 22483366Sjulian VOP_UNLOCK(ndp->ni_dvp, 0, td); 2251541Srgrimes if (ndp->ni_loopcnt++ >= MAXSYMLINKS) { 2261541Srgrimes error = ELOOP; 2271541Srgrimes break; 2281541Srgrimes } 229101127Srwatson#ifdef MAC 230105479Srwatson if ((cnp->cn_flags & NOMACCHECK) == 0) { 231105479Srwatson error = mac_check_vnode_readlink(td->td_ucred, 232105479Srwatson ndp->ni_vp); 233105479Srwatson if (error) 234105479Srwatson break; 235105479Srwatson } 236101127Srwatson#endif 2371541Srgrimes if (ndp->ni_pathlen > 1) 238111119Simp cp = uma_zalloc(namei_zone, M_WAITOK); 2391541Srgrimes else 2401541Srgrimes cp = cnp->cn_pnbuf; 2411541Srgrimes aiov.iov_base = cp; 2421541Srgrimes aiov.iov_len = MAXPATHLEN; 2431541Srgrimes auio.uio_iov = &aiov; 2441541Srgrimes auio.uio_iovcnt = 1; 2451541Srgrimes auio.uio_offset = 0; 2461541Srgrimes auio.uio_rw = UIO_READ; 2471541Srgrimes auio.uio_segflg = UIO_SYSSPACE; 24883366Sjulian auio.uio_td = (struct thread *)0; 2491541Srgrimes auio.uio_resid = MAXPATHLEN; 2503148Sphk error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); 2513148Sphk if (error) { 2521541Srgrimes if (ndp->ni_pathlen > 1) 25392751Sjeff uma_zfree(namei_zone, cp); 2541541Srgrimes break; 2551541Srgrimes } 2561541Srgrimes linklen = MAXPATHLEN - auio.uio_resid; 25778692Sdillon if (linklen == 0) { 25878692Sdillon if (ndp->ni_pathlen > 1) 25992751Sjeff uma_zfree(namei_zone, cp); 26078692Sdillon error = ENOENT; 26178692Sdillon break; 26278692Sdillon } 2631541Srgrimes if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { 2641541Srgrimes if (ndp->ni_pathlen > 1) 26592751Sjeff uma_zfree(namei_zone, cp); 2661541Srgrimes error = ENAMETOOLONG; 2671541Srgrimes break; 2681541Srgrimes } 2691541Srgrimes if (ndp->ni_pathlen > 1) { 2701541Srgrimes bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen); 27192751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 2721541Srgrimes cnp->cn_pnbuf = cp; 2731541Srgrimes } else 2741541Srgrimes cnp->cn_pnbuf[linklen] = '\0'; 2751541Srgrimes ndp->ni_pathlen += linklen; 2761541Srgrimes vput(ndp->ni_vp); 2771541Srgrimes dp = ndp->ni_dvp; 2781541Srgrimes } 27992751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 280100613Srwatson#ifdef DIAGNOSTIC 281100613Srwatson cnp->cn_pnbuf = NULL; 282100613Srwatson cnp->cn_nameptr = NULL; 283100613Srwatson#endif 2841541Srgrimes vrele(ndp->ni_dvp); 285140714Sjeff mp = ndp->ni_vp->v_mount; 2861541Srgrimes vput(ndp->ni_vp); 287140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 2881541Srgrimes ndp->ni_vp = NULL; 2891541Srgrimes return (error); 2901541Srgrimes} 2911541Srgrimes 2921541Srgrimes/* 2931541Srgrimes * Search a pathname. 2941541Srgrimes * This is a very central and rather complicated routine. 2951541Srgrimes * 2961541Srgrimes * The pathname is pointed to by ni_ptr and is of length ni_pathlen. 2971541Srgrimes * The starting directory is taken from ni_startdir. The pathname is 2981541Srgrimes * descended until done, or a symbolic link is encountered. The variable 2991541Srgrimes * ni_more is clear if the path is completed; it is set to one if a 3001541Srgrimes * symbolic link needing interpretation is encountered. 3011541Srgrimes * 3021541Srgrimes * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 3031541Srgrimes * whether the name is to be looked up, created, renamed, or deleted. 3041541Srgrimes * When CREATE, RENAME, or DELETE is specified, information usable in 3051541Srgrimes * creating, renaming, or deleting a directory entry may be calculated. 3061541Srgrimes * If flag has LOCKPARENT or'ed into it, the parent directory is returned 3071541Srgrimes * locked. If flag has WANTPARENT or'ed into it, the parent directory is 3081541Srgrimes * returned unlocked. Otherwise the parent directory is not returned. If 3091541Srgrimes * the target of the pathname exists and LOCKLEAF is or'ed into the flag 3101541Srgrimes * the target is returned locked, otherwise it is returned unlocked. 3111541Srgrimes * When creating or renaming and LOCKPARENT is specified, the target may not 3121541Srgrimes * be ".". When deleting and LOCKPARENT is specified, the target may be ".". 3138876Srgrimes * 3141541Srgrimes * Overall outline of lookup: 3151541Srgrimes * 3161541Srgrimes * dirloop: 3171541Srgrimes * identify next component of name at ndp->ni_ptr 3181541Srgrimes * handle degenerate case where name is null string 3191541Srgrimes * if .. and crossing mount points and on mounted filesys, find parent 3201541Srgrimes * call VOP_LOOKUP routine for next component name 3211541Srgrimes * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set 3221541Srgrimes * component vnode returned in ni_vp (if it exists), locked. 3231541Srgrimes * if result vnode is mounted on and crossing mount points, 3241541Srgrimes * find mounted on vnode 3251541Srgrimes * if more components of name, do next level at dirloop 3261541Srgrimes * return the answer in ni_vp, locked if LOCKLEAF set 3271541Srgrimes * if LOCKPARENT set, return locked parent in ni_dvp 3281541Srgrimes * if WANTPARENT set, return unlocked parent in ni_dvp 3291541Srgrimes */ 3301541Srgrimesint 3311541Srgrimeslookup(ndp) 3321541Srgrimes register struct nameidata *ndp; 3331541Srgrimes{ 3341541Srgrimes register char *cp; /* pointer into pathname argument */ 3351541Srgrimes register struct vnode *dp = 0; /* the directory we are searching */ 3361541Srgrimes struct vnode *tdp; /* saved dp */ 3371541Srgrimes struct mount *mp; /* mount table entry */ 3381541Srgrimes int docache; /* == 0 do not cache last component */ 3391541Srgrimes int wantparent; /* 1 => wantparent or lockparent flag */ 3401541Srgrimes int rdonly; /* lookup read-only flag bit */ 3419804Sbde int trailing_slash; 3421541Srgrimes int error = 0; 34365805Sbp int dpunlocked = 0; /* dp has already been unlocked */ 3441541Srgrimes struct componentname *cnp = &ndp->ni_cnd; 34583366Sjulian struct thread *td = cnp->cn_thread; 346140714Sjeff int vfslocked; 347140714Sjeff int tvfslocked; 3481541Srgrimes 3491541Srgrimes /* 3501541Srgrimes * Setup: break out flag bits into variables. 3511541Srgrimes */ 352140714Sjeff vfslocked = (ndp->ni_cnd.cn_flags & GIANTHELD) != 0; 353140714Sjeff ndp->ni_cnd.cn_flags &= ~GIANTHELD; 3541541Srgrimes wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 355144229Sjeff KASSERT(cnp->cn_nameiop == LOOKUP || wantparent, 356144229Sjeff ("CREATE, DELETE, RENAME require LOCKPARENT or WANTPARENT.")); 3571541Srgrimes docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 3581541Srgrimes if (cnp->cn_nameiop == DELETE || 35922874Sbde (wantparent && cnp->cn_nameiop != CREATE && 36022874Sbde cnp->cn_nameiop != LOOKUP)) 3611541Srgrimes docache = 0; 3621541Srgrimes rdonly = cnp->cn_flags & RDONLY; 3631541Srgrimes ndp->ni_dvp = NULL; 3641541Srgrimes cnp->cn_flags &= ~ISSYMLINK; 3651541Srgrimes dp = ndp->ni_startdir; 3661541Srgrimes ndp->ni_startdir = NULLVP; 36783366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 3681541Srgrimes 3691541Srgrimesdirloop: 3701541Srgrimes /* 3711541Srgrimes * Search a new directory. 3721541Srgrimes * 3731541Srgrimes * The last component of the filename is left accessible via 3741541Srgrimes * cnp->cn_nameptr for callers that need the name. Callers needing 3751541Srgrimes * the name set the SAVENAME flag. When done, they assume 3761541Srgrimes * responsibility for freeing the pathname buffer. 3771541Srgrimes */ 3781541Srgrimes cnp->cn_consume = 0; 3791541Srgrimes for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 38051906Sphk continue; 3811541Srgrimes cnp->cn_namelen = cp - cnp->cn_nameptr; 3821541Srgrimes if (cnp->cn_namelen > NAME_MAX) { 3831541Srgrimes error = ENAMETOOLONG; 3841541Srgrimes goto bad; 3851541Srgrimes } 3861541Srgrimes#ifdef NAMEI_DIAGNOSTIC 3871541Srgrimes { char c = *cp; 3881541Srgrimes *cp = '\0'; 3891541Srgrimes printf("{%s}: ", cnp->cn_nameptr); 3901541Srgrimes *cp = c; } 3911541Srgrimes#endif 3921541Srgrimes ndp->ni_pathlen -= cnp->cn_namelen; 3931541Srgrimes ndp->ni_next = cp; 3949804Sbde 3959804Sbde /* 3969804Sbde * Replace multiple slashes by a single slash and trailing slashes 3979804Sbde * by a null. This must be done before VOP_LOOKUP() because some 3989804Sbde * fs's don't know about trailing slashes. Remember if there were 3999804Sbde * trailing slashes to handle symlinks, existing non-directories 4009804Sbde * and non-existing files that won't be directories specially later. 4019804Sbde */ 4029804Sbde trailing_slash = 0; 4039804Sbde while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) { 4049804Sbde cp++; 4059804Sbde ndp->ni_pathlen--; 4069804Sbde if (*cp == '\0') { 4079804Sbde trailing_slash = 1; 4089804Sbde *ndp->ni_next = '\0'; /* XXX for direnter() ... */ 4099804Sbde } 4109804Sbde } 4119804Sbde ndp->ni_next = cp; 4129804Sbde 4131541Srgrimes cnp->cn_flags |= MAKEENTRY; 4141541Srgrimes if (*cp == '\0' && docache == 0) 4151541Srgrimes cnp->cn_flags &= ~MAKEENTRY; 4161541Srgrimes if (cnp->cn_namelen == 2 && 4171541Srgrimes cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 4181541Srgrimes cnp->cn_flags |= ISDOTDOT; 4191541Srgrimes else 4201541Srgrimes cnp->cn_flags &= ~ISDOTDOT; 4211541Srgrimes if (*ndp->ni_next == 0) 4221541Srgrimes cnp->cn_flags |= ISLASTCN; 4231541Srgrimes else 4241541Srgrimes cnp->cn_flags &= ~ISLASTCN; 4251541Srgrimes 4261541Srgrimes 4271541Srgrimes /* 4281541Srgrimes * Check for degenerate name (e.g. / or "") 4291541Srgrimes * which is a way of talking about a directory, 4301541Srgrimes * e.g. like "/." or ".". 4311541Srgrimes */ 4321541Srgrimes if (cnp->cn_nameptr[0] == '\0') { 43322521Sdyson if (dp->v_type != VDIR) { 43422521Sdyson error = ENOTDIR; 43522521Sdyson goto bad; 43622521Sdyson } 4371541Srgrimes if (cnp->cn_nameiop != LOOKUP) { 4381541Srgrimes error = EISDIR; 4391541Srgrimes goto bad; 4401541Srgrimes } 4411541Srgrimes if (wantparent) { 4421541Srgrimes ndp->ni_dvp = dp; 4431541Srgrimes VREF(dp); 4441541Srgrimes } 4451541Srgrimes ndp->ni_vp = dp; 4461541Srgrimes if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) 44783366Sjulian VOP_UNLOCK(dp, 0, td); 44854655Seivind /* XXX This should probably move to the top of function. */ 4491541Srgrimes if (cnp->cn_flags & SAVESTART) 4501541Srgrimes panic("lookup: SAVESTART"); 451140714Sjeff goto success; 4521541Srgrimes } 4531541Srgrimes 4541541Srgrimes /* 4551541Srgrimes * Handle "..": two special cases. 4561541Srgrimes * 1. If at root directory (e.g. after chroot) 4571541Srgrimes * or at absolute root directory 4581541Srgrimes * then ignore it so can't get out. 4591541Srgrimes * 2. If this vnode is the root of a mounted 4601541Srgrimes * filesystem, then replace it with the 4611541Srgrimes * vnode which was mounted on so we take the 46296755Strhodes * .. in the other filesystem. 46351649Sphk * 3. If the vnode is the top directory of 46451649Sphk * the jail or chroot, don't let them out. 4651541Srgrimes */ 4661541Srgrimes if (cnp->cn_flags & ISDOTDOT) { 4671541Srgrimes for (;;) { 46851649Sphk if (dp == ndp->ni_rootdir || 46951649Sphk dp == ndp->ni_topdir || 47051649Sphk dp == rootvnode) { 4711541Srgrimes ndp->ni_dvp = dp; 4721541Srgrimes ndp->ni_vp = dp; 4731541Srgrimes VREF(dp); 4741541Srgrimes goto nextname; 4751541Srgrimes } 476101308Sjeff if ((dp->v_vflag & VV_ROOT) == 0 || 4771541Srgrimes (cnp->cn_flags & NOCROSSMOUNT)) 4781541Srgrimes break; 47969405Salfred if (dp->v_mount == NULL) { /* forced unmount */ 48069405Salfred error = EBADF; 48169405Salfred goto bad; 48269405Salfred } 4831541Srgrimes tdp = dp; 484140714Sjeff tvfslocked = vfslocked; 4851541Srgrimes dp = dp->v_mount->mnt_vnodecovered; 4861541Srgrimes vput(tdp); 487140714Sjeff vfslocked = VFS_LOCK_GIANT(dp->v_mount); 488140714Sjeff VFS_UNLOCK_GIANT(tvfslocked); 4891541Srgrimes VREF(dp); 49083366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 4911541Srgrimes } 4921541Srgrimes } 4931541Srgrimes 4941541Srgrimes /* 4951541Srgrimes * We now have a segment name to search for, and a directory to search. 4961541Srgrimes */ 4971541Srgrimesunionlookup: 498101127Srwatson#ifdef MAC 499105479Srwatson if ((cnp->cn_flags & NOMACCHECK) == 0) { 500105479Srwatson error = mac_check_vnode_lookup(td->td_ucred, dp, cnp); 501105479Srwatson if (error) 502105479Srwatson goto bad; 503105479Srwatson } 504101127Srwatson#endif 5051541Srgrimes ndp->ni_dvp = dp; 50622521Sdyson ndp->ni_vp = NULL; 50724624Sdfr ASSERT_VOP_LOCKED(dp, "lookup"); 508138345Sphk#ifdef NAMEI_DIAGNOSTIC 509138345Sphk vprint("lookup in", dp); 510138345Sphk#endif 51143301Sdillon if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) { 51242408Seivind KASSERT(ndp->ni_vp == NULL, ("leaf should be empty")); 5131541Srgrimes#ifdef NAMEI_DIAGNOSTIC 5141541Srgrimes printf("not found\n"); 5151541Srgrimes#endif 5161541Srgrimes if ((error == ENOENT) && 517101308Sjeff (dp->v_vflag & VV_ROOT) && (dp->v_mount != NULL) && 5181541Srgrimes (dp->v_mount->mnt_flag & MNT_UNION)) { 5191541Srgrimes tdp = dp; 520140714Sjeff tvfslocked = vfslocked; 5211541Srgrimes dp = dp->v_mount->mnt_vnodecovered; 522144203Sjeff vput(tdp); 523140714Sjeff vfslocked = VFS_LOCK_GIANT(dp->v_mount); 524140714Sjeff VFS_UNLOCK_GIANT(tvfslocked); 5251541Srgrimes VREF(dp); 52683366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 5271541Srgrimes goto unionlookup; 5281541Srgrimes } 5291541Srgrimes 5301541Srgrimes if (error != EJUSTRETURN) 5311541Srgrimes goto bad; 5321541Srgrimes /* 5331541Srgrimes * If creating and at end of pathname, then can consider 5341541Srgrimes * allowing file to be created. 5351541Srgrimes */ 53611644Sdg if (rdonly) { 5371541Srgrimes error = EROFS; 5381541Srgrimes goto bad; 5391541Srgrimes } 5409804Sbde if (*cp == '\0' && trailing_slash && 5419804Sbde !(cnp->cn_flags & WILLBEDIR)) { 5429804Sbde error = ENOENT; 5439804Sbde goto bad; 5449804Sbde } 545144203Sjeff if ((cnp->cn_flags & LOCKPARENT) == 0) 546144203Sjeff VOP_UNLOCK(dp, 0, td); 5471541Srgrimes /* 548144203Sjeff * This is a temporary assert to make sure I know what the 549144203Sjeff * behavior here was. 550144203Sjeff */ 551144203Sjeff KASSERT((cnp->cn_flags & (WANTPARENT|LOCKPARENT)) != 0, 552144203Sjeff ("lookup: Unhandled case.")); 553144203Sjeff /* 5541541Srgrimes * We return with ni_vp NULL to indicate that the entry 5551541Srgrimes * doesn't currently exist, leaving a pointer to the 5561541Srgrimes * (possibly locked) directory inode in ndp->ni_dvp. 5571541Srgrimes */ 5581541Srgrimes if (cnp->cn_flags & SAVESTART) { 5591541Srgrimes ndp->ni_startdir = ndp->ni_dvp; 5601541Srgrimes VREF(ndp->ni_startdir); 5611541Srgrimes } 562140714Sjeff goto success; 5631541Srgrimes } 5641541Srgrimes#ifdef NAMEI_DIAGNOSTIC 5651541Srgrimes printf("found\n"); 5661541Srgrimes#endif 567144203Sjeff /* 568144203Sjeff * In the DOTDOT case dp is unlocked, we may have to relock it if 569144203Sjeff * this is the parent of the last component. Otherwise, we have to 570144203Sjeff * unlock if this is not the last component, or if it is and 571144203Sjeff * LOCKPARENT is set. 572144203Sjeff */ 573144203Sjeff if (cnp->cn_flags & ISDOTDOT) { 574144203Sjeff if ((cnp->cn_flags & (ISLASTCN | LOCKPARENT)) == 575144203Sjeff (ISLASTCN | LOCKPARENT)) 576144203Sjeff vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 577144203Sjeff } else if (dp != ndp->ni_vp) { 578144203Sjeff if ((cnp->cn_flags & (ISLASTCN | LOCKPARENT)) == ISLASTCN) 579144203Sjeff VOP_UNLOCK(dp, 0, td); 580144203Sjeff else if ((cnp->cn_flags & ISLASTCN) == 0) 581144203Sjeff VOP_UNLOCK(dp, 0, td); 582144203Sjeff } 5831541Srgrimes 5841541Srgrimes /* 5851541Srgrimes * Take into account any additional components consumed by 5861541Srgrimes * the underlying filesystem. 5871541Srgrimes */ 5881541Srgrimes if (cnp->cn_consume > 0) { 5891541Srgrimes cnp->cn_nameptr += cnp->cn_consume; 5901541Srgrimes ndp->ni_next += cnp->cn_consume; 5911541Srgrimes ndp->ni_pathlen -= cnp->cn_consume; 5921541Srgrimes cnp->cn_consume = 0; 5931541Srgrimes } 5941541Srgrimes 5951541Srgrimes dp = ndp->ni_vp; 5961541Srgrimes 5971541Srgrimes /* 5981541Srgrimes * Check to see if the vnode has been mounted on; 59996755Strhodes * if so find the root of the mounted filesystem. 6001541Srgrimes */ 6011541Srgrimes while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 6021541Srgrimes (cnp->cn_flags & NOCROSSMOUNT) == 0) { 60383366Sjulian if (vfs_busy(mp, 0, 0, td)) 6041541Srgrimes continue; 60583366Sjulian VOP_UNLOCK(dp, 0, td); 606140714Sjeff tvfslocked = VFS_LOCK_GIANT(mp); 607144055Sjeff error = VFS_ROOT(mp, LK_EXCLUSIVE, &tdp, td); 60883366Sjulian vfs_unbusy(mp, td); 60965805Sbp if (error) { 610140714Sjeff VFS_UNLOCK_GIANT(tvfslocked); 61165805Sbp dpunlocked = 1; 6121541Srgrimes goto bad2; 61365805Sbp } 61465805Sbp vrele(dp); 615140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 6161541Srgrimes ndp->ni_vp = dp = tdp; 617140714Sjeff vfslocked = tvfslocked; 6181541Srgrimes } 6191541Srgrimes 62010219Sdfr /* 62110219Sdfr * Check for symbolic link 62210219Sdfr */ 62310219Sdfr if ((dp->v_type == VLNK) && 62410219Sdfr ((cnp->cn_flags & FOLLOW) || trailing_slash || 62510219Sdfr *ndp->ni_next == '/')) { 62610219Sdfr cnp->cn_flags |= ISSYMLINK; 62769405Salfred if (dp->v_mount == NULL) { 62869405Salfred /* We can't know whether the directory was mounted with 62969405Salfred * NOSYMFOLLOW, so we can't follow safely. */ 63069405Salfred error = EBADF; 63169405Salfred goto bad2; 63269405Salfred } 63335105Swosch if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) { 63435105Swosch error = EACCES; 63535105Swosch goto bad2; 63635105Swosch } 637140714Sjeff goto success; 63810219Sdfr } 63910219Sdfr 64010219Sdfr /* 64110219Sdfr * Check for bogus trailing slashes. 64210219Sdfr */ 64310219Sdfr if (trailing_slash && dp->v_type != VDIR) { 64410219Sdfr error = ENOTDIR; 64510219Sdfr goto bad2; 64610219Sdfr } 64710219Sdfr 6481541Srgrimesnextname: 6491541Srgrimes /* 6501541Srgrimes * Not a symbolic link. If more pathname, 6511541Srgrimes * continue at next component, else return. 6521541Srgrimes */ 653144203Sjeff KASSERT((cnp->cn_flags & ISLASTCN) || *ndp->ni_next == '/', 654144203Sjeff ("lookup: invalid path state.")); 6551541Srgrimes if (*ndp->ni_next == '/') { 6561541Srgrimes cnp->cn_nameptr = ndp->ni_next; 6571541Srgrimes while (*cnp->cn_nameptr == '/') { 6581541Srgrimes cnp->cn_nameptr++; 6591541Srgrimes ndp->ni_pathlen--; 6601541Srgrimes } 66154655Seivind if (ndp->ni_dvp != ndp->ni_vp) 66254655Seivind ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "lookup"); 6631541Srgrimes vrele(ndp->ni_dvp); 6641541Srgrimes goto dirloop; 6651541Srgrimes } 6661541Srgrimes /* 66796755Strhodes * Disallow directory write attempts on read-only filesystems. 6681541Srgrimes */ 66911644Sdg if (rdonly && 67011644Sdg (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 67111644Sdg error = EROFS; 67211644Sdg goto bad2; 6731541Srgrimes } 6741541Srgrimes if (cnp->cn_flags & SAVESTART) { 6751541Srgrimes ndp->ni_startdir = ndp->ni_dvp; 6761541Srgrimes VREF(ndp->ni_startdir); 6771541Srgrimes } 6781541Srgrimes if (!wantparent) 6791541Srgrimes vrele(ndp->ni_dvp); 68032071Sdyson 6811541Srgrimes if ((cnp->cn_flags & LOCKLEAF) == 0) 68283366Sjulian VOP_UNLOCK(dp, 0, td); 683140714Sjeffsuccess: 684140714Sjeff if (vfslocked) 685140714Sjeff ndp->ni_cnd.cn_flags |= GIANTHELD; 6861541Srgrimes return (0); 6871541Srgrimes 6881541Srgrimesbad2: 689144203Sjeff if ((cnp->cn_flags & LOCKPARENT) && *ndp->ni_next == '\0') 690144203Sjeff vput(ndp->ni_dvp); 691144203Sjeff else 692144203Sjeff vrele(ndp->ni_dvp); 6931541Srgrimesbad: 69465805Sbp if (dpunlocked) 69565805Sbp vrele(dp); 69665805Sbp else 69765805Sbp vput(dp); 698140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 699140714Sjeff ndp->ni_cnd.cn_flags &= ~GIANTHELD; 7001541Srgrimes ndp->ni_vp = NULL; 7011541Srgrimes return (error); 7021541Srgrimes} 7031541Srgrimes 7043148Sphk/* 7053148Sphk * relookup - lookup a path name component 7063148Sphk * Used by lookup to re-aquire things. 7073148Sphk */ 7083148Sphkint 7093148Sphkrelookup(dvp, vpp, cnp) 7103148Sphk struct vnode *dvp, **vpp; 7113148Sphk struct componentname *cnp; 7123148Sphk{ 71383366Sjulian struct thread *td = cnp->cn_thread; 71422521Sdyson struct vnode *dp = 0; /* the directory we are searching */ 7153148Sphk int wantparent; /* 1 => wantparent or lockparent flag */ 7163148Sphk int rdonly; /* lookup read-only flag bit */ 7173148Sphk int error = 0; 7181541Srgrimes 719144203Sjeff KASSERT(cnp->cn_flags & ISLASTCN, 720144203Sjeff ("relookup: Not given last component.")); 7213148Sphk /* 7223148Sphk * Setup: break out flag bits into variables. 7233148Sphk */ 7243148Sphk wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 7253148Sphk rdonly = cnp->cn_flags & RDONLY; 7263148Sphk cnp->cn_flags &= ~ISSYMLINK; 7273148Sphk dp = dvp; 72883366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 7293148Sphk 7303148Sphk /* 7313148Sphk * Search a new directory. 7323148Sphk * 7333148Sphk * The last component of the filename is left accessible via 7343148Sphk * cnp->cn_nameptr for callers that need the name. Callers needing 7353148Sphk * the name set the SAVENAME flag. When done, they assume 7363148Sphk * responsibility for freeing the pathname buffer. 7373148Sphk */ 7383148Sphk#ifdef NAMEI_DIAGNOSTIC 7393148Sphk printf("{%s}: ", cnp->cn_nameptr); 7403148Sphk#endif 7413148Sphk 7423148Sphk /* 7433148Sphk * Check for degenerate name (e.g. / or "") 7443148Sphk * which is a way of talking about a directory, 7453148Sphk * e.g. like "/." or ".". 7463148Sphk */ 7473148Sphk if (cnp->cn_nameptr[0] == '\0') { 7483148Sphk if (cnp->cn_nameiop != LOOKUP || wantparent) { 7493148Sphk error = EISDIR; 7503148Sphk goto bad; 7513148Sphk } 7523148Sphk if (dp->v_type != VDIR) { 7533148Sphk error = ENOTDIR; 7543148Sphk goto bad; 7553148Sphk } 7563148Sphk if (!(cnp->cn_flags & LOCKLEAF)) 75783366Sjulian VOP_UNLOCK(dp, 0, td); 7583148Sphk *vpp = dp; 75954655Seivind /* XXX This should probably move to the top of function. */ 7603148Sphk if (cnp->cn_flags & SAVESTART) 7613148Sphk panic("lookup: SAVESTART"); 7623148Sphk return (0); 7633148Sphk } 7643148Sphk 7653148Sphk if (cnp->cn_flags & ISDOTDOT) 7663148Sphk panic ("relookup: lookup on dot-dot"); 7673148Sphk 7683148Sphk /* 7693148Sphk * We now have a segment name to search for, and a directory to search. 7703148Sphk */ 771138345Sphk#ifdef NAMEI_DIAGNOSTIC 772138345Sphk vprint("search in:", dp); 773138345Sphk#endif 77443311Sdillon if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) { 77542408Seivind KASSERT(*vpp == NULL, ("leaf should be empty")); 7763148Sphk if (error != EJUSTRETURN) 7773148Sphk goto bad; 7783148Sphk /* 7793148Sphk * If creating and at end of pathname, then can consider 7803148Sphk * allowing file to be created. 7813148Sphk */ 78211644Sdg if (rdonly) { 7833148Sphk error = EROFS; 7843148Sphk goto bad; 7853148Sphk } 7863148Sphk /* ASSERT(dvp == ndp->ni_startdir) */ 7873148Sphk if (cnp->cn_flags & SAVESTART) 7883148Sphk VREF(dvp); 789144203Sjeff if ((cnp->cn_flags & LOCKPARENT) == 0) 790144203Sjeff VOP_UNLOCK(dp, 0, td); 7913148Sphk /* 792144203Sjeff * This is a temporary assert to make sure I know what the 793144203Sjeff * behavior here was. 794144203Sjeff */ 795144203Sjeff KASSERT((cnp->cn_flags & (WANTPARENT|LOCKPARENT)) != 0, 796144203Sjeff ("relookup: Unhandled case.")); 797144203Sjeff /* 7983148Sphk * We return with ni_vp NULL to indicate that the entry 7993148Sphk * doesn't currently exist, leaving a pointer to the 8003148Sphk * (possibly locked) directory inode in ndp->ni_dvp. 8013148Sphk */ 8023148Sphk return (0); 8033148Sphk } 804144203Sjeff /* 805144203Sjeff * In the DOTDOT case dp is unlocked, we may have to relock it if 806144203Sjeff * LOCKPARENT is set. Otherwise, unlock the parent. 807144203Sjeff */ 808144203Sjeff if ((cnp->cn_flags & (ISDOTDOT | LOCKPARENT)) == 809144203Sjeff (ISDOTDOT | LOCKPARENT)) 810144203Sjeff vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 811144203Sjeff else if ((cnp->cn_flags & (ISDOTDOT | LOCKPARENT)) == 0 && dp != *vpp) 812144203Sjeff VOP_UNLOCK(dp, 0, td); 8133148Sphk dp = *vpp; 8143148Sphk 8153148Sphk /* 8163148Sphk * Check for symbolic link 8173148Sphk */ 81842408Seivind KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW), 81942453Seivind ("relookup: symlink found.\n")); 8203148Sphk 8213148Sphk /* 82296755Strhodes * Disallow directory write attempts on read-only filesystems. 8233148Sphk */ 82411644Sdg if (rdonly && 82511644Sdg (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 82611644Sdg error = EROFS; 82711644Sdg goto bad2; 8283148Sphk } 8293148Sphk /* ASSERT(dvp == ndp->ni_startdir) */ 8303148Sphk if (cnp->cn_flags & SAVESTART) 8313148Sphk VREF(dvp); 83222521Sdyson 8333148Sphk if (!wantparent) 8343148Sphk vrele(dvp); 83532071Sdyson 8363148Sphk if ((cnp->cn_flags & LOCKLEAF) == 0) 83783366Sjulian VOP_UNLOCK(dp, 0, td); 8383148Sphk return (0); 8393148Sphk 8403148Sphkbad2: 841144203Sjeff if (cnp->cn_flags & LOCKPARENT) 84283366Sjulian VOP_UNLOCK(dvp, 0, td); 8433148Sphk vrele(dvp); 8443148Sphkbad: 8453148Sphk vput(dp); 8463148Sphk *vpp = NULL; 8473148Sphk return (error); 8483148Sphk} 849141471Sjhb 850141471Sjhb/* 851141471Sjhb * Determine if there is a suitable alternate filename under the specified 852141471Sjhb * prefix for the specified path. If the create flag is set, then the 853141471Sjhb * alternate prefix will be used so long as the parent directory exists. 854141471Sjhb * This is used by the various compatiblity ABIs so that Linux binaries prefer 855141471Sjhb * files under /compat/linux for example. The chosen path (whether under 856141471Sjhb * the prefix or under /) is returned in a kernel malloc'd buffer pointed 857141471Sjhb * to by pathbuf. The caller is responsible for free'ing the buffer from 858141471Sjhb * the M_TEMP bucket if one is returned. 859141471Sjhb */ 860141471Sjhbint 861141471Sjhbkern_alternate_path(struct thread *td, const char *prefix, char *path, 862141471Sjhb enum uio_seg pathseg, char **pathbuf, int create) 863141471Sjhb{ 864141471Sjhb struct nameidata nd, ndroot; 865141471Sjhb char *ptr, *buf, *cp; 866141471Sjhb size_t len, sz; 867141471Sjhb int error; 868141471Sjhb 869141471Sjhb buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 870141471Sjhb *pathbuf = buf; 871141471Sjhb 872141471Sjhb /* Copy the prefix into the new pathname as a starting point. */ 873141471Sjhb len = strlcpy(buf, prefix, MAXPATHLEN); 874141471Sjhb if (len >= MAXPATHLEN) { 875141471Sjhb *pathbuf = NULL; 876141471Sjhb free(buf, M_TEMP); 877141471Sjhb return (EINVAL); 878141471Sjhb } 879141471Sjhb sz = MAXPATHLEN - len; 880141471Sjhb ptr = buf + len; 881141471Sjhb 882141471Sjhb /* Append the filename to the prefix. */ 883141471Sjhb if (pathseg == UIO_SYSSPACE) 884141471Sjhb error = copystr(path, ptr, sz, &len); 885141471Sjhb else 886141471Sjhb error = copyinstr(path, ptr, sz, &len); 887141471Sjhb 888141471Sjhb if (error) { 889141471Sjhb *pathbuf = NULL; 890141471Sjhb free(buf, M_TEMP); 891141471Sjhb return (error); 892141471Sjhb } 893141471Sjhb 894141471Sjhb /* Only use a prefix with absolute pathnames. */ 895141471Sjhb if (*ptr != '/') { 896141471Sjhb error = EINVAL; 897141471Sjhb goto keeporig; 898141471Sjhb } 899141471Sjhb 900141471Sjhb /* XXX: VFS_LOCK_GIANT? */ 901141471Sjhb mtx_lock(&Giant); 902141471Sjhb 903141471Sjhb /* 904141471Sjhb * We know that there is a / somewhere in this pathname. 905141471Sjhb * Search backwards for it, to find the file's parent dir 906141471Sjhb * to see if it exists in the alternate tree. If it does, 907141471Sjhb * and we want to create a file (cflag is set). We don't 908141471Sjhb * need to worry about the root comparison in this case. 909141471Sjhb */ 910141471Sjhb 911141471Sjhb if (create) { 912141471Sjhb for (cp = &ptr[len] - 1; *cp != '/'; cp--); 913141471Sjhb *cp = '\0'; 914141471Sjhb 915141471Sjhb NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td); 916141471Sjhb error = namei(&nd); 917141471Sjhb *cp = '/'; 918141471Sjhb if (error != 0) 919141471Sjhb goto nd_failed; 920141471Sjhb } else { 921141471Sjhb NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td); 922141471Sjhb 923141471Sjhb error = namei(&nd); 924141471Sjhb if (error != 0) 925141471Sjhb goto nd_failed; 926141471Sjhb 927141471Sjhb /* 928141471Sjhb * We now compare the vnode of the prefix to the one 929141471Sjhb * vnode asked. If they resolve to be the same, then we 930141471Sjhb * ignore the match so that the real root gets used. 931141471Sjhb * This avoids the problem of traversing "../.." to find the 932141471Sjhb * root directory and never finding it, because "/" resolves 933141471Sjhb * to the emulation root directory. This is expensive :-( 934141471Sjhb */ 935141471Sjhb NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix, td); 936141471Sjhb 937141471Sjhb /* We shouldn't ever get an error from this namei(). */ 938141471Sjhb error = namei(&ndroot); 939141471Sjhb if (error == 0) { 940141471Sjhb if (nd.ni_vp == ndroot.ni_vp) 941141471Sjhb error = ENOENT; 942141471Sjhb 943141471Sjhb NDFREE(&ndroot, NDF_ONLY_PNBUF); 944141471Sjhb vrele(ndroot.ni_vp); 945141471Sjhb } 946141471Sjhb } 947141471Sjhb 948141471Sjhb NDFREE(&nd, NDF_ONLY_PNBUF); 949141471Sjhb vrele(nd.ni_vp); 950141471Sjhb 951141471Sjhbnd_failed: 952141471Sjhb /* XXX: VFS_UNLOCK_GIANT? */ 953141471Sjhb mtx_unlock(&Giant); 954141471Sjhb 955141471Sjhbkeeporig: 956141471Sjhb /* If there was an error, use the original path name. */ 957141471Sjhb if (error) 958141471Sjhb bcopy(ptr, buf, len); 959141471Sjhb return (error); 960141471Sjhb} 961