vfs_lookup.c revision 139804
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 139804 2005-01-06 23:35:40Z imp $"); 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> 541541Srgrimes#ifdef KTRACE 551541Srgrimes#include <sys/ktrace.h> 561541Srgrimes#endif 571541Srgrimes 5892751Sjeff#include <vm/uma.h> 5932011Sbde 60138345Sphk#define NAMEI_DIAGNOSTIC 1 61138345Sphk#undef NAMEI_DIAGNOSTIC 62138345Sphk 631541Srgrimes/* 6469664Speter * Allocation zone for namei 6569664Speter */ 6692751Sjeffuma_zone_t namei_zone; 6769664Speter 6869664Speterstatic void 6969664Speternameiinit(void *dummy __unused) 7069664Speter{ 7192654Sjeff namei_zone = uma_zcreate("NAMEI", MAXPATHLEN, NULL, NULL, NULL, NULL, 7292654Sjeff UMA_ALIGN_PTR, 0); 7369664Speter 7469664Speter} 7569664SpeterSYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL) 7669664Speter 7769664Speter/* 781541Srgrimes * Convert a pathname into a pointer to a locked inode. 791541Srgrimes * 801541Srgrimes * The FOLLOW flag is set when symbolic links are to be followed 811541Srgrimes * when they occur at the end of the name translation process. 821541Srgrimes * Symbolic links are always followed for all other pathname 831541Srgrimes * components other than the last. 841541Srgrimes * 851541Srgrimes * The segflg defines whether the name is to be copied from user 861541Srgrimes * space or kernel space. 871541Srgrimes * 881541Srgrimes * Overall outline of namei: 891541Srgrimes * 901541Srgrimes * copy in name 911541Srgrimes * get starting directory 921541Srgrimes * while (!done && !error) { 931541Srgrimes * call lookup to search path. 941541Srgrimes * if symbolic link, massage name in buffer and continue 951541Srgrimes * } 961541Srgrimes */ 971541Srgrimesint 981541Srgrimesnamei(ndp) 991541Srgrimes register struct nameidata *ndp; 1001541Srgrimes{ 1011541Srgrimes register struct filedesc *fdp; /* pointer to file descriptor state */ 1021541Srgrimes register char *cp; /* pointer into pathname argument */ 1031541Srgrimes register struct vnode *dp; /* the directory we are searching */ 1041541Srgrimes struct iovec aiov; /* uio for reading symbolic links */ 1051541Srgrimes struct uio auio; 1061541Srgrimes int error, linklen; 1071541Srgrimes struct componentname *cnp = &ndp->ni_cnd; 10883366Sjulian struct thread *td = cnp->cn_thread; 10983366Sjulian struct proc *p = td->td_proc; 1101541Srgrimes 111133131Srwatson GIANT_REQUIRED; 112133131Srwatson 11391419Sjhb ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_thread->td_ucred; 11483366Sjulian KASSERT(cnp->cn_cred && p, ("namei: bad cred/proc")); 11542408Seivind KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0, 11642453Seivind ("namei: nameiop contaminated with flags")); 11742408Seivind KASSERT((cnp->cn_flags & OPMASK) == 0, 11842453Seivind ("namei: flags contaminated with nameiops")); 11983366Sjulian fdp = p->p_fd; 1201541Srgrimes 1211541Srgrimes /* 1221541Srgrimes * Get a buffer for the name to be translated, and copy the 1231541Srgrimes * name into the buffer. 1241541Srgrimes */ 1251541Srgrimes if ((cnp->cn_flags & HASBUF) == 0) 126111119Simp cnp->cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK); 1271541Srgrimes if (ndp->ni_segflg == UIO_SYSSPACE) 1281541Srgrimes error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 12936735Sdfr MAXPATHLEN, (size_t *)&ndp->ni_pathlen); 1301541Srgrimes else 1311541Srgrimes error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 13236735Sdfr MAXPATHLEN, (size_t *)&ndp->ni_pathlen); 13320069Sbde 13420069Sbde /* 13520069Sbde * Don't allow empty pathnames. 13620069Sbde */ 13720069Sbde if (!error && *cnp->cn_pnbuf == '\0') 13820069Sbde error = ENOENT; 13920069Sbde 1401541Srgrimes if (error) { 14192751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 142100613Srwatson#ifdef DIAGNOSTIC 143100613Srwatson cnp->cn_pnbuf = NULL; 144100613Srwatson cnp->cn_nameptr = NULL; 145100613Srwatson#endif 1461541Srgrimes ndp->ni_vp = NULL; 1471541Srgrimes return (error); 1481541Srgrimes } 1491541Srgrimes ndp->ni_loopcnt = 0; 1501541Srgrimes#ifdef KTRACE 15197994Sjhb if (KTRPOINT(td, KTR_NAMEI)) { 15297994Sjhb KASSERT(cnp->cn_thread == curthread, 15397994Sjhb ("namei not using curthread")); 15497994Sjhb ktrnamei(cnp->cn_pnbuf); 15597994Sjhb } 1561541Srgrimes#endif 1571541Srgrimes 1581541Srgrimes /* 1591541Srgrimes * Get starting point for the translation. 1601541Srgrimes */ 16189306Salfred FILEDESC_LOCK(fdp); 16233360Sdyson ndp->ni_rootdir = fdp->fd_rdir; 16351649Sphk ndp->ni_topdir = fdp->fd_jdir; 16433360Sdyson 1651541Srgrimes dp = fdp->fd_cdir; 1661541Srgrimes VREF(dp); 16789306Salfred FILEDESC_UNLOCK(fdp); 1681541Srgrimes for (;;) { 1691541Srgrimes /* 1701541Srgrimes * Check if root directory should replace current directory. 1711541Srgrimes * Done at start of translation and after symbolic link. 1721541Srgrimes */ 1731541Srgrimes cnp->cn_nameptr = cnp->cn_pnbuf; 1741541Srgrimes if (*(cnp->cn_nameptr) == '/') { 1751541Srgrimes vrele(dp); 1761541Srgrimes while (*(cnp->cn_nameptr) == '/') { 1771541Srgrimes cnp->cn_nameptr++; 1781541Srgrimes ndp->ni_pathlen--; 1791541Srgrimes } 1801541Srgrimes dp = ndp->ni_rootdir; 1811541Srgrimes VREF(dp); 1821541Srgrimes } 1831541Srgrimes ndp->ni_startdir = dp; 1843148Sphk error = lookup(ndp); 1853148Sphk if (error) { 18692751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 187100613Srwatson#ifdef DIAGNOSTIC 188100613Srwatson cnp->cn_pnbuf = NULL; 189100613Srwatson cnp->cn_nameptr = NULL; 190100613Srwatson#endif 1911541Srgrimes return (error); 1921541Srgrimes } 1931541Srgrimes /* 1941541Srgrimes * Check for symbolic link 1951541Srgrimes */ 1961541Srgrimes if ((cnp->cn_flags & ISSYMLINK) == 0) { 197100613Srwatson if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) { 19892751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 199100613Srwatson#ifdef DIAGNOSTIC 200100613Srwatson cnp->cn_pnbuf = NULL; 201100613Srwatson cnp->cn_nameptr = NULL; 202100613Srwatson#endif 203100613Srwatson } else 2041541Srgrimes cnp->cn_flags |= HASBUF; 20532286Sdyson 20649101Salc if (vn_canvmio(ndp->ni_vp) == TRUE && 20732286Sdyson (cnp->cn_nameiop != DELETE) && 20842315Seivind ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == 20942315Seivind LOCKLEAF)) 21083366Sjulian vfs_object_create(ndp->ni_vp, td, 21142315Seivind ndp->ni_cnd.cn_cred); 21232286Sdyson 2131541Srgrimes return (0); 2141541Srgrimes } 2151541Srgrimes if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1) 21683366Sjulian VOP_UNLOCK(ndp->ni_dvp, 0, td); 2171541Srgrimes if (ndp->ni_loopcnt++ >= MAXSYMLINKS) { 2181541Srgrimes error = ELOOP; 2191541Srgrimes break; 2201541Srgrimes } 221101127Srwatson#ifdef MAC 222105479Srwatson if ((cnp->cn_flags & NOMACCHECK) == 0) { 223105479Srwatson error = mac_check_vnode_readlink(td->td_ucred, 224105479Srwatson ndp->ni_vp); 225105479Srwatson if (error) 226105479Srwatson break; 227105479Srwatson } 228101127Srwatson#endif 2291541Srgrimes if (ndp->ni_pathlen > 1) 230111119Simp cp = uma_zalloc(namei_zone, M_WAITOK); 2311541Srgrimes else 2321541Srgrimes cp = cnp->cn_pnbuf; 2331541Srgrimes aiov.iov_base = cp; 2341541Srgrimes aiov.iov_len = MAXPATHLEN; 2351541Srgrimes auio.uio_iov = &aiov; 2361541Srgrimes auio.uio_iovcnt = 1; 2371541Srgrimes auio.uio_offset = 0; 2381541Srgrimes auio.uio_rw = UIO_READ; 2391541Srgrimes auio.uio_segflg = UIO_SYSSPACE; 24083366Sjulian auio.uio_td = (struct thread *)0; 2411541Srgrimes auio.uio_resid = MAXPATHLEN; 2423148Sphk error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); 2433148Sphk if (error) { 2441541Srgrimes if (ndp->ni_pathlen > 1) 24592751Sjeff uma_zfree(namei_zone, cp); 2461541Srgrimes break; 2471541Srgrimes } 2481541Srgrimes linklen = MAXPATHLEN - auio.uio_resid; 24978692Sdillon if (linklen == 0) { 25078692Sdillon if (ndp->ni_pathlen > 1) 25192751Sjeff uma_zfree(namei_zone, cp); 25278692Sdillon error = ENOENT; 25378692Sdillon break; 25478692Sdillon } 2551541Srgrimes if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { 2561541Srgrimes if (ndp->ni_pathlen > 1) 25792751Sjeff uma_zfree(namei_zone, cp); 2581541Srgrimes error = ENAMETOOLONG; 2591541Srgrimes break; 2601541Srgrimes } 2611541Srgrimes if (ndp->ni_pathlen > 1) { 2621541Srgrimes bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen); 26392751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 2641541Srgrimes cnp->cn_pnbuf = cp; 2651541Srgrimes } else 2661541Srgrimes cnp->cn_pnbuf[linklen] = '\0'; 2671541Srgrimes ndp->ni_pathlen += linklen; 2681541Srgrimes vput(ndp->ni_vp); 2691541Srgrimes dp = ndp->ni_dvp; 2701541Srgrimes } 27192751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 272100613Srwatson#ifdef DIAGNOSTIC 273100613Srwatson cnp->cn_pnbuf = NULL; 274100613Srwatson cnp->cn_nameptr = NULL; 275100613Srwatson#endif 2761541Srgrimes vrele(ndp->ni_dvp); 2771541Srgrimes vput(ndp->ni_vp); 2781541Srgrimes ndp->ni_vp = NULL; 2791541Srgrimes return (error); 2801541Srgrimes} 2811541Srgrimes 2821541Srgrimes/* 2831541Srgrimes * Search a pathname. 2841541Srgrimes * This is a very central and rather complicated routine. 2851541Srgrimes * 2861541Srgrimes * The pathname is pointed to by ni_ptr and is of length ni_pathlen. 2871541Srgrimes * The starting directory is taken from ni_startdir. The pathname is 2881541Srgrimes * descended until done, or a symbolic link is encountered. The variable 2891541Srgrimes * ni_more is clear if the path is completed; it is set to one if a 2901541Srgrimes * symbolic link needing interpretation is encountered. 2911541Srgrimes * 2921541Srgrimes * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 2931541Srgrimes * whether the name is to be looked up, created, renamed, or deleted. 2941541Srgrimes * When CREATE, RENAME, or DELETE is specified, information usable in 2951541Srgrimes * creating, renaming, or deleting a directory entry may be calculated. 2961541Srgrimes * If flag has LOCKPARENT or'ed into it, the parent directory is returned 2971541Srgrimes * locked. If flag has WANTPARENT or'ed into it, the parent directory is 2981541Srgrimes * returned unlocked. Otherwise the parent directory is not returned. If 2991541Srgrimes * the target of the pathname exists and LOCKLEAF is or'ed into the flag 3001541Srgrimes * the target is returned locked, otherwise it is returned unlocked. 3011541Srgrimes * When creating or renaming and LOCKPARENT is specified, the target may not 3021541Srgrimes * be ".". When deleting and LOCKPARENT is specified, the target may be ".". 3038876Srgrimes * 3041541Srgrimes * Overall outline of lookup: 3051541Srgrimes * 3061541Srgrimes * dirloop: 3071541Srgrimes * identify next component of name at ndp->ni_ptr 3081541Srgrimes * handle degenerate case where name is null string 3091541Srgrimes * if .. and crossing mount points and on mounted filesys, find parent 3101541Srgrimes * call VOP_LOOKUP routine for next component name 3111541Srgrimes * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set 3121541Srgrimes * component vnode returned in ni_vp (if it exists), locked. 3131541Srgrimes * if result vnode is mounted on and crossing mount points, 3141541Srgrimes * find mounted on vnode 3151541Srgrimes * if more components of name, do next level at dirloop 3161541Srgrimes * return the answer in ni_vp, locked if LOCKLEAF set 3171541Srgrimes * if LOCKPARENT set, return locked parent in ni_dvp 3181541Srgrimes * if WANTPARENT set, return unlocked parent in ni_dvp 3191541Srgrimes */ 3201541Srgrimesint 3211541Srgrimeslookup(ndp) 3221541Srgrimes register struct nameidata *ndp; 3231541Srgrimes{ 3241541Srgrimes register char *cp; /* pointer into pathname argument */ 3251541Srgrimes register struct vnode *dp = 0; /* the directory we are searching */ 3261541Srgrimes struct vnode *tdp; /* saved dp */ 3271541Srgrimes struct mount *mp; /* mount table entry */ 3281541Srgrimes int docache; /* == 0 do not cache last component */ 3291541Srgrimes int wantparent; /* 1 => wantparent or lockparent flag */ 3301541Srgrimes int rdonly; /* lookup read-only flag bit */ 3319804Sbde int trailing_slash; 3321541Srgrimes int error = 0; 33365805Sbp int dpunlocked = 0; /* dp has already been unlocked */ 3341541Srgrimes struct componentname *cnp = &ndp->ni_cnd; 33583366Sjulian struct thread *td = cnp->cn_thread; 3361541Srgrimes 3371541Srgrimes /* 3381541Srgrimes * Setup: break out flag bits into variables. 3391541Srgrimes */ 3401541Srgrimes wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 3411541Srgrimes docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 3421541Srgrimes if (cnp->cn_nameiop == DELETE || 34322874Sbde (wantparent && cnp->cn_nameiop != CREATE && 34422874Sbde cnp->cn_nameiop != LOOKUP)) 3451541Srgrimes docache = 0; 3461541Srgrimes rdonly = cnp->cn_flags & RDONLY; 3471541Srgrimes ndp->ni_dvp = NULL; 3481541Srgrimes cnp->cn_flags &= ~ISSYMLINK; 3491541Srgrimes dp = ndp->ni_startdir; 3501541Srgrimes ndp->ni_startdir = NULLVP; 35183366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 3521541Srgrimes 3531541Srgrimesdirloop: 3541541Srgrimes /* 3551541Srgrimes * Search a new directory. 3561541Srgrimes * 3571541Srgrimes * The last component of the filename is left accessible via 3581541Srgrimes * cnp->cn_nameptr for callers that need the name. Callers needing 3591541Srgrimes * the name set the SAVENAME flag. When done, they assume 3601541Srgrimes * responsibility for freeing the pathname buffer. 3611541Srgrimes */ 3621541Srgrimes cnp->cn_consume = 0; 3631541Srgrimes for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 36451906Sphk continue; 3651541Srgrimes cnp->cn_namelen = cp - cnp->cn_nameptr; 3661541Srgrimes if (cnp->cn_namelen > NAME_MAX) { 3671541Srgrimes error = ENAMETOOLONG; 3681541Srgrimes goto bad; 3691541Srgrimes } 3701541Srgrimes#ifdef NAMEI_DIAGNOSTIC 3711541Srgrimes { char c = *cp; 3721541Srgrimes *cp = '\0'; 3731541Srgrimes printf("{%s}: ", cnp->cn_nameptr); 3741541Srgrimes *cp = c; } 3751541Srgrimes#endif 3761541Srgrimes ndp->ni_pathlen -= cnp->cn_namelen; 3771541Srgrimes ndp->ni_next = cp; 3789804Sbde 3799804Sbde /* 3809804Sbde * Replace multiple slashes by a single slash and trailing slashes 3819804Sbde * by a null. This must be done before VOP_LOOKUP() because some 3829804Sbde * fs's don't know about trailing slashes. Remember if there were 3839804Sbde * trailing slashes to handle symlinks, existing non-directories 3849804Sbde * and non-existing files that won't be directories specially later. 3859804Sbde */ 3869804Sbde trailing_slash = 0; 3879804Sbde while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) { 3889804Sbde cp++; 3899804Sbde ndp->ni_pathlen--; 3909804Sbde if (*cp == '\0') { 3919804Sbde trailing_slash = 1; 3929804Sbde *ndp->ni_next = '\0'; /* XXX for direnter() ... */ 3939804Sbde } 3949804Sbde } 3959804Sbde ndp->ni_next = cp; 3969804Sbde 3971541Srgrimes cnp->cn_flags |= MAKEENTRY; 3981541Srgrimes if (*cp == '\0' && docache == 0) 3991541Srgrimes cnp->cn_flags &= ~MAKEENTRY; 4001541Srgrimes if (cnp->cn_namelen == 2 && 4011541Srgrimes cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 4021541Srgrimes cnp->cn_flags |= ISDOTDOT; 4031541Srgrimes else 4041541Srgrimes cnp->cn_flags &= ~ISDOTDOT; 4051541Srgrimes if (*ndp->ni_next == 0) 4061541Srgrimes cnp->cn_flags |= ISLASTCN; 4071541Srgrimes else 4081541Srgrimes cnp->cn_flags &= ~ISLASTCN; 4091541Srgrimes 4101541Srgrimes 4111541Srgrimes /* 4121541Srgrimes * Check for degenerate name (e.g. / or "") 4131541Srgrimes * which is a way of talking about a directory, 4141541Srgrimes * e.g. like "/." or ".". 4151541Srgrimes */ 4161541Srgrimes if (cnp->cn_nameptr[0] == '\0') { 41722521Sdyson if (dp->v_type != VDIR) { 41822521Sdyson error = ENOTDIR; 41922521Sdyson goto bad; 42022521Sdyson } 4211541Srgrimes if (cnp->cn_nameiop != LOOKUP) { 4221541Srgrimes error = EISDIR; 4231541Srgrimes goto bad; 4241541Srgrimes } 4251541Srgrimes if (wantparent) { 4261541Srgrimes ndp->ni_dvp = dp; 4271541Srgrimes VREF(dp); 4281541Srgrimes } 4291541Srgrimes ndp->ni_vp = dp; 4301541Srgrimes if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) 43183366Sjulian VOP_UNLOCK(dp, 0, td); 43254655Seivind /* XXX This should probably move to the top of function. */ 4331541Srgrimes if (cnp->cn_flags & SAVESTART) 4341541Srgrimes panic("lookup: SAVESTART"); 4351541Srgrimes return (0); 4361541Srgrimes } 4371541Srgrimes 4381541Srgrimes /* 4391541Srgrimes * Handle "..": two special cases. 4401541Srgrimes * 1. If at root directory (e.g. after chroot) 4411541Srgrimes * or at absolute root directory 4421541Srgrimes * then ignore it so can't get out. 4431541Srgrimes * 2. If this vnode is the root of a mounted 4441541Srgrimes * filesystem, then replace it with the 4451541Srgrimes * vnode which was mounted on so we take the 44696755Strhodes * .. in the other filesystem. 44751649Sphk * 3. If the vnode is the top directory of 44851649Sphk * the jail or chroot, don't let them out. 4491541Srgrimes */ 4501541Srgrimes if (cnp->cn_flags & ISDOTDOT) { 4511541Srgrimes for (;;) { 45251649Sphk if (dp == ndp->ni_rootdir || 45351649Sphk dp == ndp->ni_topdir || 45451649Sphk dp == rootvnode) { 4551541Srgrimes ndp->ni_dvp = dp; 4561541Srgrimes ndp->ni_vp = dp; 4571541Srgrimes VREF(dp); 4581541Srgrimes goto nextname; 4591541Srgrimes } 460101308Sjeff if ((dp->v_vflag & VV_ROOT) == 0 || 4611541Srgrimes (cnp->cn_flags & NOCROSSMOUNT)) 4621541Srgrimes break; 46369405Salfred if (dp->v_mount == NULL) { /* forced unmount */ 46469405Salfred error = EBADF; 46569405Salfred goto bad; 46669405Salfred } 4671541Srgrimes tdp = dp; 4681541Srgrimes dp = dp->v_mount->mnt_vnodecovered; 4691541Srgrimes vput(tdp); 4701541Srgrimes VREF(dp); 47183366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 4721541Srgrimes } 4731541Srgrimes } 4741541Srgrimes 4751541Srgrimes /* 4761541Srgrimes * We now have a segment name to search for, and a directory to search. 4771541Srgrimes */ 4781541Srgrimesunionlookup: 479101127Srwatson#ifdef MAC 480105479Srwatson if ((cnp->cn_flags & NOMACCHECK) == 0) { 481105479Srwatson error = mac_check_vnode_lookup(td->td_ucred, dp, cnp); 482105479Srwatson if (error) 483105479Srwatson goto bad; 484105479Srwatson } 485101127Srwatson#endif 4861541Srgrimes ndp->ni_dvp = dp; 48722521Sdyson ndp->ni_vp = NULL; 48865973Sbp cnp->cn_flags &= ~PDIRUNLOCK; 48924624Sdfr ASSERT_VOP_LOCKED(dp, "lookup"); 490138345Sphk#ifdef NAMEI_DIAGNOSTIC 491138345Sphk vprint("lookup in", dp); 492138345Sphk#endif 49343301Sdillon if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) { 49442408Seivind KASSERT(ndp->ni_vp == NULL, ("leaf should be empty")); 4951541Srgrimes#ifdef NAMEI_DIAGNOSTIC 4961541Srgrimes printf("not found\n"); 4971541Srgrimes#endif 4981541Srgrimes if ((error == ENOENT) && 499101308Sjeff (dp->v_vflag & VV_ROOT) && (dp->v_mount != NULL) && 5001541Srgrimes (dp->v_mount->mnt_flag & MNT_UNION)) { 5011541Srgrimes tdp = dp; 5021541Srgrimes dp = dp->v_mount->mnt_vnodecovered; 50365973Sbp if (cnp->cn_flags & PDIRUNLOCK) 50465973Sbp vrele(tdp); 50565973Sbp else 50665973Sbp vput(tdp); 5071541Srgrimes VREF(dp); 50883366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 5091541Srgrimes goto unionlookup; 5101541Srgrimes } 5111541Srgrimes 5121541Srgrimes if (error != EJUSTRETURN) 5131541Srgrimes goto bad; 5141541Srgrimes /* 5151541Srgrimes * If creating and at end of pathname, then can consider 5161541Srgrimes * allowing file to be created. 5171541Srgrimes */ 51811644Sdg if (rdonly) { 5191541Srgrimes error = EROFS; 5201541Srgrimes goto bad; 5211541Srgrimes } 5229804Sbde if (*cp == '\0' && trailing_slash && 5239804Sbde !(cnp->cn_flags & WILLBEDIR)) { 5249804Sbde error = ENOENT; 5259804Sbde goto bad; 5269804Sbde } 5271541Srgrimes /* 5281541Srgrimes * We return with ni_vp NULL to indicate that the entry 5291541Srgrimes * doesn't currently exist, leaving a pointer to the 5301541Srgrimes * (possibly locked) directory inode in ndp->ni_dvp. 5311541Srgrimes */ 5321541Srgrimes if (cnp->cn_flags & SAVESTART) { 5331541Srgrimes ndp->ni_startdir = ndp->ni_dvp; 5341541Srgrimes VREF(ndp->ni_startdir); 5351541Srgrimes } 5361541Srgrimes return (0); 5371541Srgrimes } 5381541Srgrimes#ifdef NAMEI_DIAGNOSTIC 5391541Srgrimes printf("found\n"); 5401541Srgrimes#endif 5411541Srgrimes 54224624Sdfr ASSERT_VOP_LOCKED(ndp->ni_vp, "lookup"); 54324624Sdfr 5441541Srgrimes /* 5451541Srgrimes * Take into account any additional components consumed by 5461541Srgrimes * the underlying filesystem. 5471541Srgrimes */ 5481541Srgrimes if (cnp->cn_consume > 0) { 5491541Srgrimes cnp->cn_nameptr += cnp->cn_consume; 5501541Srgrimes ndp->ni_next += cnp->cn_consume; 5511541Srgrimes ndp->ni_pathlen -= cnp->cn_consume; 5521541Srgrimes cnp->cn_consume = 0; 5531541Srgrimes } 5541541Srgrimes 5551541Srgrimes dp = ndp->ni_vp; 5561541Srgrimes 5571541Srgrimes /* 5581541Srgrimes * Check to see if the vnode has been mounted on; 55996755Strhodes * if so find the root of the mounted filesystem. 5601541Srgrimes */ 5611541Srgrimes while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 5621541Srgrimes (cnp->cn_flags & NOCROSSMOUNT) == 0) { 56383366Sjulian if (vfs_busy(mp, 0, 0, td)) 5641541Srgrimes continue; 56583366Sjulian VOP_UNLOCK(dp, 0, td); 566132023Salfred error = VFS_ROOT(mp, &tdp, td); 56783366Sjulian vfs_unbusy(mp, td); 56865805Sbp if (error) { 56965805Sbp dpunlocked = 1; 5701541Srgrimes goto bad2; 57165805Sbp } 57265805Sbp vrele(dp); 5731541Srgrimes ndp->ni_vp = dp = tdp; 5741541Srgrimes } 5751541Srgrimes 57610219Sdfr /* 57710219Sdfr * Check for symbolic link 57810219Sdfr */ 57910219Sdfr if ((dp->v_type == VLNK) && 58010219Sdfr ((cnp->cn_flags & FOLLOW) || trailing_slash || 58110219Sdfr *ndp->ni_next == '/')) { 58210219Sdfr cnp->cn_flags |= ISSYMLINK; 58369405Salfred if (dp->v_mount == NULL) { 58469405Salfred /* We can't know whether the directory was mounted with 58569405Salfred * NOSYMFOLLOW, so we can't follow safely. */ 58669405Salfred error = EBADF; 58769405Salfred goto bad2; 58869405Salfred } 58935105Swosch if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) { 59035105Swosch error = EACCES; 59135105Swosch goto bad2; 59235105Swosch } 59310219Sdfr return (0); 59410219Sdfr } 59510219Sdfr 59610219Sdfr /* 59710219Sdfr * Check for bogus trailing slashes. 59810219Sdfr */ 59910219Sdfr if (trailing_slash && dp->v_type != VDIR) { 60010219Sdfr error = ENOTDIR; 60110219Sdfr goto bad2; 60210219Sdfr } 60310219Sdfr 6041541Srgrimesnextname: 6051541Srgrimes /* 6061541Srgrimes * Not a symbolic link. If more pathname, 6071541Srgrimes * continue at next component, else return. 6081541Srgrimes */ 6091541Srgrimes if (*ndp->ni_next == '/') { 6101541Srgrimes cnp->cn_nameptr = ndp->ni_next; 6111541Srgrimes while (*cnp->cn_nameptr == '/') { 6121541Srgrimes cnp->cn_nameptr++; 6131541Srgrimes ndp->ni_pathlen--; 6141541Srgrimes } 61554655Seivind if (ndp->ni_dvp != ndp->ni_vp) 61654655Seivind ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "lookup"); 6171541Srgrimes vrele(ndp->ni_dvp); 6181541Srgrimes goto dirloop; 6191541Srgrimes } 6201541Srgrimes /* 62196755Strhodes * Disallow directory write attempts on read-only filesystems. 6221541Srgrimes */ 62311644Sdg if (rdonly && 62411644Sdg (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 62511644Sdg error = EROFS; 62611644Sdg goto bad2; 6271541Srgrimes } 6281541Srgrimes if (cnp->cn_flags & SAVESTART) { 6291541Srgrimes ndp->ni_startdir = ndp->ni_dvp; 6301541Srgrimes VREF(ndp->ni_startdir); 6311541Srgrimes } 6321541Srgrimes if (!wantparent) 6331541Srgrimes vrele(ndp->ni_dvp); 63432071Sdyson 6351541Srgrimes if ((cnp->cn_flags & LOCKLEAF) == 0) 63683366Sjulian VOP_UNLOCK(dp, 0, td); 6371541Srgrimes return (0); 6381541Srgrimes 6391541Srgrimesbad2: 64065973Sbp if ((cnp->cn_flags & (LOCKPARENT | PDIRUNLOCK)) == LOCKPARENT && 64165973Sbp *ndp->ni_next == '\0') 64283366Sjulian VOP_UNLOCK(ndp->ni_dvp, 0, td); 6431541Srgrimes vrele(ndp->ni_dvp); 6441541Srgrimesbad: 64565805Sbp if (dpunlocked) 64665805Sbp vrele(dp); 64765805Sbp else 64865805Sbp vput(dp); 6491541Srgrimes ndp->ni_vp = NULL; 6501541Srgrimes return (error); 6511541Srgrimes} 6521541Srgrimes 6533148Sphk/* 6543148Sphk * relookup - lookup a path name component 6553148Sphk * Used by lookup to re-aquire things. 6563148Sphk */ 6573148Sphkint 6583148Sphkrelookup(dvp, vpp, cnp) 6593148Sphk struct vnode *dvp, **vpp; 6603148Sphk struct componentname *cnp; 6613148Sphk{ 66283366Sjulian struct thread *td = cnp->cn_thread; 66322521Sdyson struct vnode *dp = 0; /* the directory we are searching */ 6643148Sphk int docache; /* == 0 do not cache last component */ 6653148Sphk int wantparent; /* 1 => wantparent or lockparent flag */ 6663148Sphk int rdonly; /* lookup read-only flag bit */ 6673148Sphk int error = 0; 6681541Srgrimes 6693148Sphk /* 6703148Sphk * Setup: break out flag bits into variables. 6713148Sphk */ 6723148Sphk wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 6733148Sphk docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 6743148Sphk if (cnp->cn_nameiop == DELETE || 6753148Sphk (wantparent && cnp->cn_nameiop != CREATE)) 6763148Sphk docache = 0; 6773148Sphk rdonly = cnp->cn_flags & RDONLY; 6783148Sphk cnp->cn_flags &= ~ISSYMLINK; 6793148Sphk dp = dvp; 68083366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 6813148Sphk 6823148Sphk/* dirloop: */ 6833148Sphk /* 6843148Sphk * Search a new directory. 6853148Sphk * 6863148Sphk * The last component of the filename is left accessible via 6873148Sphk * cnp->cn_nameptr for callers that need the name. Callers needing 6883148Sphk * the name set the SAVENAME flag. When done, they assume 6893148Sphk * responsibility for freeing the pathname buffer. 6903148Sphk */ 6913148Sphk#ifdef NAMEI_DIAGNOSTIC 6923148Sphk printf("{%s}: ", cnp->cn_nameptr); 6933148Sphk#endif 6943148Sphk 6953148Sphk /* 6963148Sphk * Check for degenerate name (e.g. / or "") 6973148Sphk * which is a way of talking about a directory, 6983148Sphk * e.g. like "/." or ".". 6993148Sphk */ 7003148Sphk if (cnp->cn_nameptr[0] == '\0') { 7013148Sphk if (cnp->cn_nameiop != LOOKUP || wantparent) { 7023148Sphk error = EISDIR; 7033148Sphk goto bad; 7043148Sphk } 7053148Sphk if (dp->v_type != VDIR) { 7063148Sphk error = ENOTDIR; 7073148Sphk goto bad; 7083148Sphk } 7093148Sphk if (!(cnp->cn_flags & LOCKLEAF)) 71083366Sjulian VOP_UNLOCK(dp, 0, td); 7113148Sphk *vpp = dp; 71254655Seivind /* XXX This should probably move to the top of function. */ 7133148Sphk if (cnp->cn_flags & SAVESTART) 7143148Sphk panic("lookup: SAVESTART"); 7153148Sphk return (0); 7163148Sphk } 7173148Sphk 7183148Sphk if (cnp->cn_flags & ISDOTDOT) 7193148Sphk panic ("relookup: lookup on dot-dot"); 7203148Sphk 7213148Sphk /* 7223148Sphk * We now have a segment name to search for, and a directory to search. 7233148Sphk */ 724138345Sphk#ifdef NAMEI_DIAGNOSTIC 725138345Sphk vprint("search in:", dp); 726138345Sphk#endif 72743311Sdillon if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) { 72842408Seivind KASSERT(*vpp == NULL, ("leaf should be empty")); 7293148Sphk if (error != EJUSTRETURN) 7303148Sphk goto bad; 7313148Sphk /* 7323148Sphk * If creating and at end of pathname, then can consider 7333148Sphk * allowing file to be created. 7343148Sphk */ 73511644Sdg if (rdonly) { 7363148Sphk error = EROFS; 7373148Sphk goto bad; 7383148Sphk } 7393148Sphk /* ASSERT(dvp == ndp->ni_startdir) */ 7403148Sphk if (cnp->cn_flags & SAVESTART) 7413148Sphk VREF(dvp); 7423148Sphk /* 7433148Sphk * We return with ni_vp NULL to indicate that the entry 7443148Sphk * doesn't currently exist, leaving a pointer to the 7453148Sphk * (possibly locked) directory inode in ndp->ni_dvp. 7463148Sphk */ 7473148Sphk return (0); 7483148Sphk } 7493148Sphk dp = *vpp; 7503148Sphk 7513148Sphk /* 7523148Sphk * Check for symbolic link 7533148Sphk */ 75442408Seivind KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW), 75542453Seivind ("relookup: symlink found.\n")); 7563148Sphk 7573148Sphk /* 75896755Strhodes * Disallow directory write attempts on read-only filesystems. 7593148Sphk */ 76011644Sdg if (rdonly && 76111644Sdg (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 76211644Sdg error = EROFS; 76311644Sdg goto bad2; 7643148Sphk } 7653148Sphk /* ASSERT(dvp == ndp->ni_startdir) */ 7663148Sphk if (cnp->cn_flags & SAVESTART) 7673148Sphk VREF(dvp); 76822521Sdyson 7693148Sphk if (!wantparent) 7703148Sphk vrele(dvp); 77132071Sdyson 77249101Salc if (vn_canvmio(dp) == TRUE && 77332286Sdyson ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == LOCKLEAF)) 77483366Sjulian vfs_object_create(dp, td, cnp->cn_cred); 77532071Sdyson 7763148Sphk if ((cnp->cn_flags & LOCKLEAF) == 0) 77783366Sjulian VOP_UNLOCK(dp, 0, td); 7783148Sphk return (0); 7793148Sphk 7803148Sphkbad2: 7813148Sphk if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) 78283366Sjulian VOP_UNLOCK(dvp, 0, td); 7833148Sphk vrele(dvp); 7843148Sphkbad: 7853148Sphk vput(dp); 7863148Sphk *vpp = NULL; 7873148Sphk return (error); 7883148Sphk} 789