vfs_lookup.c revision 144833
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 144833 2005-04-09 11:53:16Z jeff $"); 39116182Sobrien 4013203Swollman#include "opt_ktrace.h" 41101127Srwatson#include "opt_mac.h" 42144613Sjeff#include "opt_vfs.h" 4313203Swollman 441541Srgrimes#include <sys/param.h> 452112Swollman#include <sys/systm.h> 4669664Speter#include <sys/kernel.h> 4776166Smarkm#include <sys/lock.h> 48101127Srwatson#include <sys/mac.h> 4989316Salfred#include <sys/mutex.h> 501541Srgrimes#include <sys/namei.h> 511541Srgrimes#include <sys/vnode.h> 521541Srgrimes#include <sys/mount.h> 531541Srgrimes#include <sys/filedesc.h> 541541Srgrimes#include <sys/proc.h> 55141471Sjhb#include <sys/syscallsubr.h> 56144613Sjeff#include <sys/sysctl.h> 571541Srgrimes#ifdef KTRACE 581541Srgrimes#include <sys/ktrace.h> 591541Srgrimes#endif 601541Srgrimes 6192751Sjeff#include <vm/uma.h> 6232011Sbde 63138345Sphk#define NAMEI_DIAGNOSTIC 1 64138345Sphk#undef NAMEI_DIAGNOSTIC 65138345Sphk 661541Srgrimes/* 6769664Speter * Allocation zone for namei 6869664Speter */ 6992751Sjeffuma_zone_t namei_zone; 7069664Speter 7169664Speterstatic void 7269664Speternameiinit(void *dummy __unused) 7369664Speter{ 7492654Sjeff namei_zone = uma_zcreate("NAMEI", MAXPATHLEN, NULL, NULL, NULL, NULL, 7592654Sjeff UMA_ALIGN_PTR, 0); 7669664Speter 7769664Speter} 7869664SpeterSYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL) 7969664Speter 80144613Sjeff#ifdef LOOKUP_SHARED 81144613Sjeffstatic int lookup_shared = 1; 82144613Sjeff#else 83144613Sjeffstatic int lookup_shared = 0; 84144613Sjeff#endif 85144613SjeffSYSCTL_INT(_vfs, OID_AUTO, lookup_shared, CTLFLAG_RW, &lookup_shared, 0, 86144613Sjeff "Enables/Disables shared locks for path name translation"); 87144613Sjeff 8869664Speter/* 891541Srgrimes * Convert a pathname into a pointer to a locked inode. 901541Srgrimes * 911541Srgrimes * The FOLLOW flag is set when symbolic links are to be followed 921541Srgrimes * when they occur at the end of the name translation process. 931541Srgrimes * Symbolic links are always followed for all other pathname 941541Srgrimes * components other than the last. 951541Srgrimes * 961541Srgrimes * The segflg defines whether the name is to be copied from user 971541Srgrimes * space or kernel space. 981541Srgrimes * 991541Srgrimes * Overall outline of namei: 1001541Srgrimes * 1011541Srgrimes * copy in name 1021541Srgrimes * get starting directory 1031541Srgrimes * while (!done && !error) { 1041541Srgrimes * call lookup to search path. 1051541Srgrimes * if symbolic link, massage name in buffer and continue 1061541Srgrimes * } 1071541Srgrimes */ 1081541Srgrimesint 1091541Srgrimesnamei(ndp) 1101541Srgrimes register struct nameidata *ndp; 1111541Srgrimes{ 1121541Srgrimes register struct filedesc *fdp; /* pointer to file descriptor state */ 1131541Srgrimes register char *cp; /* pointer into pathname argument */ 1141541Srgrimes register struct vnode *dp; /* the directory we are searching */ 1151541Srgrimes struct iovec aiov; /* uio for reading symbolic links */ 1161541Srgrimes struct uio auio; 1171541Srgrimes int error, linklen; 1181541Srgrimes struct componentname *cnp = &ndp->ni_cnd; 11983366Sjulian struct thread *td = cnp->cn_thread; 12083366Sjulian struct proc *p = td->td_proc; 121140714Sjeff int vfslocked; 1221541Srgrimes 12391419Sjhb ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_thread->td_ucred; 12483366Sjulian KASSERT(cnp->cn_cred && p, ("namei: bad cred/proc")); 12542408Seivind KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0, 12642453Seivind ("namei: nameiop contaminated with flags")); 12742408Seivind KASSERT((cnp->cn_flags & OPMASK) == 0, 12842453Seivind ("namei: flags contaminated with nameiops")); 129144613Sjeff if (!lookup_shared) 130144613Sjeff cnp->cn_flags &= ~LOCKSHARED; 13183366Sjulian fdp = p->p_fd; 1321541Srgrimes 1331541Srgrimes /* 1341541Srgrimes * Get a buffer for the name to be translated, and copy the 1351541Srgrimes * name into the buffer. 1361541Srgrimes */ 1371541Srgrimes if ((cnp->cn_flags & HASBUF) == 0) 138111119Simp cnp->cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK); 1391541Srgrimes if (ndp->ni_segflg == UIO_SYSSPACE) 1401541Srgrimes error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, 14136735Sdfr MAXPATHLEN, (size_t *)&ndp->ni_pathlen); 1421541Srgrimes else 1431541Srgrimes error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, 14436735Sdfr MAXPATHLEN, (size_t *)&ndp->ni_pathlen); 14520069Sbde 14620069Sbde /* 14720069Sbde * Don't allow empty pathnames. 14820069Sbde */ 14920069Sbde if (!error && *cnp->cn_pnbuf == '\0') 15020069Sbde error = ENOENT; 15120069Sbde 1521541Srgrimes if (error) { 15392751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 154100613Srwatson#ifdef DIAGNOSTIC 155100613Srwatson cnp->cn_pnbuf = NULL; 156100613Srwatson cnp->cn_nameptr = NULL; 157100613Srwatson#endif 1581541Srgrimes ndp->ni_vp = NULL; 1591541Srgrimes return (error); 1601541Srgrimes } 1611541Srgrimes ndp->ni_loopcnt = 0; 1621541Srgrimes#ifdef KTRACE 16397994Sjhb if (KTRPOINT(td, KTR_NAMEI)) { 16497994Sjhb KASSERT(cnp->cn_thread == curthread, 16597994Sjhb ("namei not using curthread")); 16697994Sjhb ktrnamei(cnp->cn_pnbuf); 16797994Sjhb } 1681541Srgrimes#endif 1691541Srgrimes 1701541Srgrimes /* 1711541Srgrimes * Get starting point for the translation. 1721541Srgrimes */ 17389306Salfred FILEDESC_LOCK(fdp); 17433360Sdyson ndp->ni_rootdir = fdp->fd_rdir; 17551649Sphk ndp->ni_topdir = fdp->fd_jdir; 17633360Sdyson 1771541Srgrimes dp = fdp->fd_cdir; 178140714Sjeff vfslocked = VFS_LOCK_GIANT(dp->v_mount); 1791541Srgrimes VREF(dp); 18089306Salfred FILEDESC_UNLOCK(fdp); 1811541Srgrimes for (;;) { 1821541Srgrimes /* 1831541Srgrimes * Check if root directory should replace current directory. 1841541Srgrimes * Done at start of translation and after symbolic link. 1851541Srgrimes */ 1861541Srgrimes cnp->cn_nameptr = cnp->cn_pnbuf; 1871541Srgrimes if (*(cnp->cn_nameptr) == '/') { 1881541Srgrimes vrele(dp); 189140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 1901541Srgrimes while (*(cnp->cn_nameptr) == '/') { 1911541Srgrimes cnp->cn_nameptr++; 1921541Srgrimes ndp->ni_pathlen--; 1931541Srgrimes } 1941541Srgrimes dp = ndp->ni_rootdir; 195140714Sjeff vfslocked = VFS_LOCK_GIANT(dp->v_mount); 1961541Srgrimes VREF(dp); 1971541Srgrimes } 198140714Sjeff if (vfslocked) 199140714Sjeff ndp->ni_cnd.cn_flags |= GIANTHELD; 2001541Srgrimes ndp->ni_startdir = dp; 2013148Sphk error = lookup(ndp); 2023148Sphk if (error) { 20392751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 204100613Srwatson#ifdef DIAGNOSTIC 205100613Srwatson cnp->cn_pnbuf = NULL; 206100613Srwatson cnp->cn_nameptr = NULL; 207100613Srwatson#endif 2081541Srgrimes return (error); 2091541Srgrimes } 210140714Sjeff vfslocked = (ndp->ni_cnd.cn_flags & GIANTHELD) != 0; 211140714Sjeff ndp->ni_cnd.cn_flags &= ~GIANTHELD; 2121541Srgrimes /* 2131541Srgrimes * Check for symbolic link 2141541Srgrimes */ 2151541Srgrimes if ((cnp->cn_flags & ISSYMLINK) == 0) { 216100613Srwatson if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) { 21792751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 218100613Srwatson#ifdef DIAGNOSTIC 219100613Srwatson cnp->cn_pnbuf = NULL; 220100613Srwatson cnp->cn_nameptr = NULL; 221100613Srwatson#endif 222100613Srwatson } else 2231541Srgrimes cnp->cn_flags |= HASBUF; 22432286Sdyson 225140714Sjeff if ((cnp->cn_flags & MPSAFE) == 0) { 226140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 227140714Sjeff } else if (vfslocked) 228140714Sjeff ndp->ni_cnd.cn_flags |= GIANTHELD; 2291541Srgrimes return (0); 2301541Srgrimes } 2311541Srgrimes if (ndp->ni_loopcnt++ >= MAXSYMLINKS) { 2321541Srgrimes error = ELOOP; 2331541Srgrimes break; 2341541Srgrimes } 235101127Srwatson#ifdef MAC 236105479Srwatson if ((cnp->cn_flags & NOMACCHECK) == 0) { 237105479Srwatson error = mac_check_vnode_readlink(td->td_ucred, 238105479Srwatson ndp->ni_vp); 239105479Srwatson if (error) 240105479Srwatson break; 241105479Srwatson } 242101127Srwatson#endif 2431541Srgrimes if (ndp->ni_pathlen > 1) 244111119Simp cp = uma_zalloc(namei_zone, M_WAITOK); 2451541Srgrimes else 2461541Srgrimes cp = cnp->cn_pnbuf; 2471541Srgrimes aiov.iov_base = cp; 2481541Srgrimes aiov.iov_len = MAXPATHLEN; 2491541Srgrimes auio.uio_iov = &aiov; 2501541Srgrimes auio.uio_iovcnt = 1; 2511541Srgrimes auio.uio_offset = 0; 2521541Srgrimes auio.uio_rw = UIO_READ; 2531541Srgrimes auio.uio_segflg = UIO_SYSSPACE; 25483366Sjulian auio.uio_td = (struct thread *)0; 2551541Srgrimes auio.uio_resid = MAXPATHLEN; 2563148Sphk error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); 2573148Sphk if (error) { 2581541Srgrimes if (ndp->ni_pathlen > 1) 25992751Sjeff uma_zfree(namei_zone, cp); 2601541Srgrimes break; 2611541Srgrimes } 2621541Srgrimes linklen = MAXPATHLEN - auio.uio_resid; 26378692Sdillon if (linklen == 0) { 26478692Sdillon if (ndp->ni_pathlen > 1) 26592751Sjeff uma_zfree(namei_zone, cp); 26678692Sdillon error = ENOENT; 26778692Sdillon break; 26878692Sdillon } 2691541Srgrimes if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { 2701541Srgrimes if (ndp->ni_pathlen > 1) 27192751Sjeff uma_zfree(namei_zone, cp); 2721541Srgrimes error = ENAMETOOLONG; 2731541Srgrimes break; 2741541Srgrimes } 2751541Srgrimes if (ndp->ni_pathlen > 1) { 2761541Srgrimes bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen); 27792751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 2781541Srgrimes cnp->cn_pnbuf = cp; 2791541Srgrimes } else 2801541Srgrimes cnp->cn_pnbuf[linklen] = '\0'; 2811541Srgrimes ndp->ni_pathlen += linklen; 2821541Srgrimes vput(ndp->ni_vp); 2831541Srgrimes dp = ndp->ni_dvp; 2841541Srgrimes } 28592751Sjeff uma_zfree(namei_zone, cnp->cn_pnbuf); 286100613Srwatson#ifdef DIAGNOSTIC 287100613Srwatson cnp->cn_pnbuf = NULL; 288100613Srwatson cnp->cn_nameptr = NULL; 289100613Srwatson#endif 290144833Sjeff vput(ndp->ni_vp); 291144833Sjeff ndp->ni_vp = NULL; 2921541Srgrimes vrele(ndp->ni_dvp); 293140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 2941541Srgrimes return (error); 2951541Srgrimes} 2961541Srgrimes 2971541Srgrimes/* 2981541Srgrimes * Search a pathname. 2991541Srgrimes * This is a very central and rather complicated routine. 3001541Srgrimes * 3011541Srgrimes * The pathname is pointed to by ni_ptr and is of length ni_pathlen. 3021541Srgrimes * The starting directory is taken from ni_startdir. The pathname is 3031541Srgrimes * descended until done, or a symbolic link is encountered. The variable 3041541Srgrimes * ni_more is clear if the path is completed; it is set to one if a 3051541Srgrimes * symbolic link needing interpretation is encountered. 3061541Srgrimes * 3071541Srgrimes * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 3081541Srgrimes * whether the name is to be looked up, created, renamed, or deleted. 3091541Srgrimes * When CREATE, RENAME, or DELETE is specified, information usable in 3101541Srgrimes * creating, renaming, or deleting a directory entry may be calculated. 3111541Srgrimes * If flag has LOCKPARENT or'ed into it, the parent directory is returned 3121541Srgrimes * locked. If flag has WANTPARENT or'ed into it, the parent directory is 3131541Srgrimes * returned unlocked. Otherwise the parent directory is not returned. If 3141541Srgrimes * the target of the pathname exists and LOCKLEAF is or'ed into the flag 3151541Srgrimes * the target is returned locked, otherwise it is returned unlocked. 3161541Srgrimes * When creating or renaming and LOCKPARENT is specified, the target may not 3171541Srgrimes * be ".". When deleting and LOCKPARENT is specified, the target may be ".". 3188876Srgrimes * 3191541Srgrimes * Overall outline of lookup: 3201541Srgrimes * 3211541Srgrimes * dirloop: 3221541Srgrimes * identify next component of name at ndp->ni_ptr 3231541Srgrimes * handle degenerate case where name is null string 3241541Srgrimes * if .. and crossing mount points and on mounted filesys, find parent 3251541Srgrimes * call VOP_LOOKUP routine for next component name 3261541Srgrimes * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set 3271541Srgrimes * component vnode returned in ni_vp (if it exists), locked. 3281541Srgrimes * if result vnode is mounted on and crossing mount points, 3291541Srgrimes * find mounted on vnode 3301541Srgrimes * if more components of name, do next level at dirloop 3311541Srgrimes * return the answer in ni_vp, locked if LOCKLEAF set 3321541Srgrimes * if LOCKPARENT set, return locked parent in ni_dvp 3331541Srgrimes * if WANTPARENT set, return unlocked parent in ni_dvp 3341541Srgrimes */ 3351541Srgrimesint 3361541Srgrimeslookup(ndp) 3371541Srgrimes register struct nameidata *ndp; 3381541Srgrimes{ 3391541Srgrimes register char *cp; /* pointer into pathname argument */ 3401541Srgrimes register struct vnode *dp = 0; /* the directory we are searching */ 3411541Srgrimes struct vnode *tdp; /* saved dp */ 3421541Srgrimes struct mount *mp; /* mount table entry */ 3431541Srgrimes int docache; /* == 0 do not cache last component */ 3441541Srgrimes int wantparent; /* 1 => wantparent or lockparent flag */ 3451541Srgrimes int rdonly; /* lookup read-only flag bit */ 3469804Sbde int trailing_slash; 3471541Srgrimes int error = 0; 34865805Sbp int dpunlocked = 0; /* dp has already been unlocked */ 3491541Srgrimes struct componentname *cnp = &ndp->ni_cnd; 35083366Sjulian struct thread *td = cnp->cn_thread; 351140714Sjeff int vfslocked; 352140714Sjeff int tvfslocked; 3531541Srgrimes 3541541Srgrimes /* 3551541Srgrimes * Setup: break out flag bits into variables. 3561541Srgrimes */ 357140714Sjeff vfslocked = (ndp->ni_cnd.cn_flags & GIANTHELD) != 0; 358140714Sjeff ndp->ni_cnd.cn_flags &= ~GIANTHELD; 3591541Srgrimes wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT); 360144229Sjeff KASSERT(cnp->cn_nameiop == LOOKUP || wantparent, 361144229Sjeff ("CREATE, DELETE, RENAME require LOCKPARENT or WANTPARENT.")); 3621541Srgrimes docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; 3631541Srgrimes if (cnp->cn_nameiop == DELETE || 36422874Sbde (wantparent && cnp->cn_nameiop != CREATE && 36522874Sbde cnp->cn_nameiop != LOOKUP)) 3661541Srgrimes docache = 0; 3671541Srgrimes rdonly = cnp->cn_flags & RDONLY; 368144286Sjeff cnp->cn_flags &= ~ISSYMLINK; 3691541Srgrimes ndp->ni_dvp = NULL; 370144286Sjeff /* 371144286Sjeff * We use shared locks until we hit the parent of the last cn then 372144286Sjeff * we adjust based on the requesting flags. 373144286Sjeff */ 374144613Sjeff if (lookup_shared) 375144613Sjeff cnp->cn_lkflags = LK_SHARED; 376144613Sjeff else 377144613Sjeff cnp->cn_lkflags = LK_EXCLUSIVE; 3781541Srgrimes dp = ndp->ni_startdir; 3791541Srgrimes ndp->ni_startdir = NULLVP; 380144286Sjeff vn_lock(dp, cnp->cn_lkflags | LK_RETRY, td); 3811541Srgrimes 3821541Srgrimesdirloop: 3831541Srgrimes /* 3841541Srgrimes * Search a new directory. 3851541Srgrimes * 3861541Srgrimes * The last component of the filename is left accessible via 3871541Srgrimes * cnp->cn_nameptr for callers that need the name. Callers needing 3881541Srgrimes * the name set the SAVENAME flag. When done, they assume 3891541Srgrimes * responsibility for freeing the pathname buffer. 3901541Srgrimes */ 3911541Srgrimes cnp->cn_consume = 0; 3921541Srgrimes for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) 39351906Sphk continue; 3941541Srgrimes cnp->cn_namelen = cp - cnp->cn_nameptr; 3951541Srgrimes if (cnp->cn_namelen > NAME_MAX) { 3961541Srgrimes error = ENAMETOOLONG; 3971541Srgrimes goto bad; 3981541Srgrimes } 3991541Srgrimes#ifdef NAMEI_DIAGNOSTIC 4001541Srgrimes { char c = *cp; 4011541Srgrimes *cp = '\0'; 4021541Srgrimes printf("{%s}: ", cnp->cn_nameptr); 4031541Srgrimes *cp = c; } 4041541Srgrimes#endif 4051541Srgrimes ndp->ni_pathlen -= cnp->cn_namelen; 4061541Srgrimes ndp->ni_next = cp; 4079804Sbde 4089804Sbde /* 4099804Sbde * Replace multiple slashes by a single slash and trailing slashes 4109804Sbde * by a null. This must be done before VOP_LOOKUP() because some 4119804Sbde * fs's don't know about trailing slashes. Remember if there were 4129804Sbde * trailing slashes to handle symlinks, existing non-directories 4139804Sbde * and non-existing files that won't be directories specially later. 4149804Sbde */ 4159804Sbde trailing_slash = 0; 4169804Sbde while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) { 4179804Sbde cp++; 4189804Sbde ndp->ni_pathlen--; 4199804Sbde if (*cp == '\0') { 4209804Sbde trailing_slash = 1; 4219804Sbde *ndp->ni_next = '\0'; /* XXX for direnter() ... */ 4229804Sbde } 4239804Sbde } 4249804Sbde ndp->ni_next = cp; 4259804Sbde 4261541Srgrimes cnp->cn_flags |= MAKEENTRY; 4271541Srgrimes if (*cp == '\0' && docache == 0) 4281541Srgrimes cnp->cn_flags &= ~MAKEENTRY; 4291541Srgrimes if (cnp->cn_namelen == 2 && 4301541Srgrimes cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') 4311541Srgrimes cnp->cn_flags |= ISDOTDOT; 4321541Srgrimes else 4331541Srgrimes cnp->cn_flags &= ~ISDOTDOT; 4341541Srgrimes if (*ndp->ni_next == 0) 4351541Srgrimes cnp->cn_flags |= ISLASTCN; 4361541Srgrimes else 4371541Srgrimes cnp->cn_flags &= ~ISLASTCN; 4381541Srgrimes 4391541Srgrimes 4401541Srgrimes /* 4411541Srgrimes * Check for degenerate name (e.g. / or "") 4421541Srgrimes * which is a way of talking about a directory, 4431541Srgrimes * e.g. like "/." or ".". 4441541Srgrimes */ 4451541Srgrimes if (cnp->cn_nameptr[0] == '\0') { 44622521Sdyson if (dp->v_type != VDIR) { 44722521Sdyson error = ENOTDIR; 44822521Sdyson goto bad; 44922521Sdyson } 4501541Srgrimes if (cnp->cn_nameiop != LOOKUP) { 4511541Srgrimes error = EISDIR; 4521541Srgrimes goto bad; 4531541Srgrimes } 4541541Srgrimes if (wantparent) { 4551541Srgrimes ndp->ni_dvp = dp; 4561541Srgrimes VREF(dp); 4571541Srgrimes } 4581541Srgrimes ndp->ni_vp = dp; 4591541Srgrimes if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) 46083366Sjulian VOP_UNLOCK(dp, 0, td); 46154655Seivind /* XXX This should probably move to the top of function. */ 4621541Srgrimes if (cnp->cn_flags & SAVESTART) 4631541Srgrimes panic("lookup: SAVESTART"); 464140714Sjeff goto success; 4651541Srgrimes } 4661541Srgrimes 4671541Srgrimes /* 4681541Srgrimes * Handle "..": two special cases. 4691541Srgrimes * 1. If at root directory (e.g. after chroot) 4701541Srgrimes * or at absolute root directory 4711541Srgrimes * then ignore it so can't get out. 4721541Srgrimes * 2. If this vnode is the root of a mounted 4731541Srgrimes * filesystem, then replace it with the 4741541Srgrimes * vnode which was mounted on so we take the 47596755Strhodes * .. in the other filesystem. 47651649Sphk * 3. If the vnode is the top directory of 47751649Sphk * the jail or chroot, don't let them out. 4781541Srgrimes */ 4791541Srgrimes if (cnp->cn_flags & ISDOTDOT) { 4801541Srgrimes for (;;) { 48151649Sphk if (dp == ndp->ni_rootdir || 48251649Sphk dp == ndp->ni_topdir || 48351649Sphk dp == rootvnode) { 4841541Srgrimes ndp->ni_dvp = dp; 4851541Srgrimes ndp->ni_vp = dp; 4861541Srgrimes VREF(dp); 4871541Srgrimes goto nextname; 4881541Srgrimes } 489101308Sjeff if ((dp->v_vflag & VV_ROOT) == 0 || 4901541Srgrimes (cnp->cn_flags & NOCROSSMOUNT)) 4911541Srgrimes break; 49269405Salfred if (dp->v_mount == NULL) { /* forced unmount */ 49369405Salfred error = EBADF; 49469405Salfred goto bad; 49569405Salfred } 4961541Srgrimes tdp = dp; 497144833Sjeff dp = dp->v_mount->mnt_vnodecovered; 498140714Sjeff tvfslocked = vfslocked; 499144833Sjeff vfslocked = VFS_LOCK_GIANT(dp->v_mount); 500144833Sjeff VREF(dp); 5011541Srgrimes vput(tdp); 502140714Sjeff VFS_UNLOCK_GIANT(tvfslocked); 503144286Sjeff vn_lock(dp, cnp->cn_lkflags | LK_RETRY, td); 5041541Srgrimes } 5051541Srgrimes } 5061541Srgrimes 5071541Srgrimes /* 5081541Srgrimes * We now have a segment name to search for, and a directory to search. 5091541Srgrimes */ 5101541Srgrimesunionlookup: 511101127Srwatson#ifdef MAC 512105479Srwatson if ((cnp->cn_flags & NOMACCHECK) == 0) { 513105479Srwatson error = mac_check_vnode_lookup(td->td_ucred, dp, cnp); 514105479Srwatson if (error) 515105479Srwatson goto bad; 516105479Srwatson } 517101127Srwatson#endif 5181541Srgrimes ndp->ni_dvp = dp; 51922521Sdyson ndp->ni_vp = NULL; 52024624Sdfr ASSERT_VOP_LOCKED(dp, "lookup"); 521144286Sjeff /* 522144286Sjeff * If we have a shared lock we may need to upgrade the lock for the 523144286Sjeff * last operation. 524144286Sjeff */ 525144286Sjeff if (VOP_ISLOCKED(dp, td) == LK_SHARED && 526144286Sjeff (cnp->cn_flags & ISLASTCN) && (cnp->cn_flags & LOCKPARENT)) 527144286Sjeff vn_lock(dp, LK_UPGRADE|LK_RETRY, td); 528144286Sjeff /* 529144286Sjeff * If we're looking up the last component and we need an exclusive 530144286Sjeff * lock, adjust our lkflags. 531144286Sjeff */ 532144286Sjeff if ((cnp->cn_flags & (ISLASTCN|LOCKSHARED|LOCKLEAF)) == 533144286Sjeff (ISLASTCN|LOCKLEAF)) 534144286Sjeff cnp->cn_lkflags = LK_EXCLUSIVE; 535138345Sphk#ifdef NAMEI_DIAGNOSTIC 536138345Sphk vprint("lookup in", dp); 537138345Sphk#endif 53843301Sdillon if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) { 53942408Seivind KASSERT(ndp->ni_vp == NULL, ("leaf should be empty")); 5401541Srgrimes#ifdef NAMEI_DIAGNOSTIC 5411541Srgrimes printf("not found\n"); 5421541Srgrimes#endif 5431541Srgrimes if ((error == ENOENT) && 544101308Sjeff (dp->v_vflag & VV_ROOT) && (dp->v_mount != NULL) && 5451541Srgrimes (dp->v_mount->mnt_flag & MNT_UNION)) { 5461541Srgrimes tdp = dp; 547144833Sjeff dp = dp->v_mount->mnt_vnodecovered; 548140714Sjeff tvfslocked = vfslocked; 549144833Sjeff vfslocked = VFS_LOCK_GIANT(dp->v_mount); 550144833Sjeff VREF(dp); 551144203Sjeff vput(tdp); 552140714Sjeff VFS_UNLOCK_GIANT(tvfslocked); 553144286Sjeff vn_lock(dp, cnp->cn_lkflags | LK_RETRY, td); 5541541Srgrimes goto unionlookup; 5551541Srgrimes } 5561541Srgrimes 5571541Srgrimes if (error != EJUSTRETURN) 5581541Srgrimes goto bad; 5591541Srgrimes /* 5601541Srgrimes * If creating and at end of pathname, then can consider 5611541Srgrimes * allowing file to be created. 5621541Srgrimes */ 56311644Sdg if (rdonly) { 5641541Srgrimes error = EROFS; 5651541Srgrimes goto bad; 5661541Srgrimes } 5679804Sbde if (*cp == '\0' && trailing_slash && 5689804Sbde !(cnp->cn_flags & WILLBEDIR)) { 5699804Sbde error = ENOENT; 5709804Sbde goto bad; 5719804Sbde } 572144203Sjeff if ((cnp->cn_flags & LOCKPARENT) == 0) 573144203Sjeff VOP_UNLOCK(dp, 0, td); 5741541Srgrimes /* 575144203Sjeff * This is a temporary assert to make sure I know what the 576144203Sjeff * behavior here was. 577144203Sjeff */ 578144203Sjeff KASSERT((cnp->cn_flags & (WANTPARENT|LOCKPARENT)) != 0, 579144203Sjeff ("lookup: Unhandled case.")); 580144203Sjeff /* 5811541Srgrimes * We return with ni_vp NULL to indicate that the entry 5821541Srgrimes * doesn't currently exist, leaving a pointer to the 5831541Srgrimes * (possibly locked) directory inode in ndp->ni_dvp. 5841541Srgrimes */ 5851541Srgrimes if (cnp->cn_flags & SAVESTART) { 5861541Srgrimes ndp->ni_startdir = ndp->ni_dvp; 5871541Srgrimes VREF(ndp->ni_startdir); 5881541Srgrimes } 589140714Sjeff goto success; 5901541Srgrimes } 5911541Srgrimes#ifdef NAMEI_DIAGNOSTIC 5921541Srgrimes printf("found\n"); 5931541Srgrimes#endif 594144203Sjeff /* 595144833Sjeff * In the DOTDOT case dp is unlocked, we relock it here even if we 596144833Sjeff * may not need it to simplify the code below. 597144203Sjeff */ 598144833Sjeff if (cnp->cn_flags & ISDOTDOT) 599144833Sjeff vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 6001541Srgrimes /* 6011541Srgrimes * Take into account any additional components consumed by 6021541Srgrimes * the underlying filesystem. 6031541Srgrimes */ 6041541Srgrimes if (cnp->cn_consume > 0) { 6051541Srgrimes cnp->cn_nameptr += cnp->cn_consume; 6061541Srgrimes ndp->ni_next += cnp->cn_consume; 6071541Srgrimes ndp->ni_pathlen -= cnp->cn_consume; 6081541Srgrimes cnp->cn_consume = 0; 6091541Srgrimes } 6101541Srgrimes 6111541Srgrimes dp = ndp->ni_vp; 6121541Srgrimes 6131541Srgrimes /* 6141541Srgrimes * Check to see if the vnode has been mounted on; 61596755Strhodes * if so find the root of the mounted filesystem. 6161541Srgrimes */ 6171541Srgrimes while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && 6181541Srgrimes (cnp->cn_flags & NOCROSSMOUNT) == 0) { 619144833Sjeff KASSERT(dp != ndp->ni_dvp, ("XXX")); 62083366Sjulian if (vfs_busy(mp, 0, 0, td)) 6211541Srgrimes continue; 622144833Sjeff vput(dp); 623140714Sjeff tvfslocked = VFS_LOCK_GIANT(mp); 624144833Sjeff VFS_UNLOCK_GIANT(vfslocked); 625144833Sjeff vfslocked = tvfslocked; 626144286Sjeff error = VFS_ROOT(mp, cnp->cn_lkflags, &tdp, td); 62783366Sjulian vfs_unbusy(mp, td); 62865805Sbp if (error) { 62965805Sbp dpunlocked = 1; 6301541Srgrimes goto bad2; 63165805Sbp } 6321541Srgrimes ndp->ni_vp = dp = tdp; 6331541Srgrimes } 6341541Srgrimes 63510219Sdfr /* 63610219Sdfr * Check for symbolic link 63710219Sdfr */ 63810219Sdfr if ((dp->v_type == VLNK) && 63910219Sdfr ((cnp->cn_flags & FOLLOW) || trailing_slash || 64010219Sdfr *ndp->ni_next == '/')) { 64110219Sdfr cnp->cn_flags |= ISSYMLINK; 64269405Salfred if (dp->v_mount == NULL) { 64369405Salfred /* We can't know whether the directory was mounted with 64469405Salfred * NOSYMFOLLOW, so we can't follow safely. */ 64569405Salfred error = EBADF; 64669405Salfred goto bad2; 64769405Salfred } 64835105Swosch if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) { 64935105Swosch error = EACCES; 65035105Swosch goto bad2; 65135105Swosch } 652144833Sjeff /* 653144833Sjeff * Symlink code always expects an unlocked dvp. 654144833Sjeff */ 655144833Sjeff if (ndp->ni_dvp != ndp->ni_vp) 656144833Sjeff VOP_UNLOCK(ndp->ni_dvp, 0, td); 657140714Sjeff goto success; 65810219Sdfr } 65910219Sdfr 66010219Sdfr /* 66110219Sdfr * Check for bogus trailing slashes. 66210219Sdfr */ 66310219Sdfr if (trailing_slash && dp->v_type != VDIR) { 66410219Sdfr error = ENOTDIR; 66510219Sdfr goto bad2; 66610219Sdfr } 66710219Sdfr 6681541Srgrimesnextname: 6691541Srgrimes /* 6701541Srgrimes * Not a symbolic link. If more pathname, 6711541Srgrimes * continue at next component, else return. 6721541Srgrimes */ 673144203Sjeff KASSERT((cnp->cn_flags & ISLASTCN) || *ndp->ni_next == '/', 674144203Sjeff ("lookup: invalid path state.")); 6751541Srgrimes if (*ndp->ni_next == '/') { 6761541Srgrimes cnp->cn_nameptr = ndp->ni_next; 6771541Srgrimes while (*cnp->cn_nameptr == '/') { 6781541Srgrimes cnp->cn_nameptr++; 6791541Srgrimes ndp->ni_pathlen--; 6801541Srgrimes } 681144833Sjeff if (ndp->ni_dvp != dp) 682144833Sjeff vput(ndp->ni_dvp); 683144833Sjeff else 684144833Sjeff vrele(ndp->ni_dvp); 6851541Srgrimes goto dirloop; 6861541Srgrimes } 6871541Srgrimes /* 68896755Strhodes * Disallow directory write attempts on read-only filesystems. 6891541Srgrimes */ 69011644Sdg if (rdonly && 69111644Sdg (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 69211644Sdg error = EROFS; 69311644Sdg goto bad2; 6941541Srgrimes } 6951541Srgrimes if (cnp->cn_flags & SAVESTART) { 6961541Srgrimes ndp->ni_startdir = ndp->ni_dvp; 6971541Srgrimes VREF(ndp->ni_startdir); 6981541Srgrimes } 699144833Sjeff if (!wantparent) { 700144833Sjeff if (ndp->ni_dvp != dp) 701144833Sjeff vput(ndp->ni_dvp); 702144833Sjeff else 703144833Sjeff vrele(ndp->ni_dvp); 704144833Sjeff } else if ((cnp->cn_flags & LOCKPARENT) == 0 && ndp->ni_dvp != dp) 705144833Sjeff VOP_UNLOCK(ndp->ni_dvp, 0, td); 70632071Sdyson 7071541Srgrimes if ((cnp->cn_flags & LOCKLEAF) == 0) 70883366Sjulian VOP_UNLOCK(dp, 0, td); 709140714Sjeffsuccess: 710140714Sjeff if (vfslocked) 711140714Sjeff ndp->ni_cnd.cn_flags |= GIANTHELD; 7121541Srgrimes return (0); 7131541Srgrimes 7141541Srgrimesbad2: 715144833Sjeff if (dp != ndp->ni_dvp) 716144203Sjeff vput(ndp->ni_dvp); 717144203Sjeff else 718144203Sjeff vrele(ndp->ni_dvp); 7191541Srgrimesbad: 720144833Sjeff if (!dpunlocked) 72165805Sbp vput(dp); 722140714Sjeff VFS_UNLOCK_GIANT(vfslocked); 723140714Sjeff ndp->ni_cnd.cn_flags &= ~GIANTHELD; 7241541Srgrimes ndp->ni_vp = NULL; 7251541Srgrimes return (error); 7261541Srgrimes} 7271541Srgrimes 7283148Sphk/* 7293148Sphk * relookup - lookup a path name component 7303148Sphk * Used by lookup to re-aquire things. 7313148Sphk */ 7323148Sphkint 7333148Sphkrelookup(dvp, vpp, cnp) 7343148Sphk struct vnode *dvp, **vpp; 7353148Sphk struct componentname *cnp; 7363148Sphk{ 73783366Sjulian struct thread *td = cnp->cn_thread; 73822521Sdyson struct vnode *dp = 0; /* the directory we are searching */ 7393148Sphk int wantparent; /* 1 => wantparent or lockparent flag */ 7403148Sphk int rdonly; /* lookup read-only flag bit */ 7413148Sphk int error = 0; 7421541Srgrimes 743144203Sjeff KASSERT(cnp->cn_flags & ISLASTCN, 744144203Sjeff ("relookup: Not given last component.")); 7453148Sphk /* 7463148Sphk * Setup: break out flag bits into variables. 7473148Sphk */ 7483148Sphk wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); 7493148Sphk rdonly = cnp->cn_flags & RDONLY; 7503148Sphk cnp->cn_flags &= ~ISSYMLINK; 7513148Sphk dp = dvp; 752144286Sjeff cnp->cn_lkflags = LK_EXCLUSIVE; 75383366Sjulian vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 7543148Sphk 7553148Sphk /* 7563148Sphk * Search a new directory. 7573148Sphk * 7583148Sphk * The last component of the filename is left accessible via 7593148Sphk * cnp->cn_nameptr for callers that need the name. Callers needing 7603148Sphk * the name set the SAVENAME flag. When done, they assume 7613148Sphk * responsibility for freeing the pathname buffer. 7623148Sphk */ 7633148Sphk#ifdef NAMEI_DIAGNOSTIC 7643148Sphk printf("{%s}: ", cnp->cn_nameptr); 7653148Sphk#endif 7663148Sphk 7673148Sphk /* 7683148Sphk * Check for degenerate name (e.g. / or "") 7693148Sphk * which is a way of talking about a directory, 7703148Sphk * e.g. like "/." or ".". 7713148Sphk */ 7723148Sphk if (cnp->cn_nameptr[0] == '\0') { 7733148Sphk if (cnp->cn_nameiop != LOOKUP || wantparent) { 7743148Sphk error = EISDIR; 7753148Sphk goto bad; 7763148Sphk } 7773148Sphk if (dp->v_type != VDIR) { 7783148Sphk error = ENOTDIR; 7793148Sphk goto bad; 7803148Sphk } 7813148Sphk if (!(cnp->cn_flags & LOCKLEAF)) 78283366Sjulian VOP_UNLOCK(dp, 0, td); 7833148Sphk *vpp = dp; 78454655Seivind /* XXX This should probably move to the top of function. */ 7853148Sphk if (cnp->cn_flags & SAVESTART) 7863148Sphk panic("lookup: SAVESTART"); 7873148Sphk return (0); 7883148Sphk } 7893148Sphk 7903148Sphk if (cnp->cn_flags & ISDOTDOT) 7913148Sphk panic ("relookup: lookup on dot-dot"); 7923148Sphk 7933148Sphk /* 7943148Sphk * We now have a segment name to search for, and a directory to search. 7953148Sphk */ 796138345Sphk#ifdef NAMEI_DIAGNOSTIC 797138345Sphk vprint("search in:", dp); 798138345Sphk#endif 79943311Sdillon if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) { 80042408Seivind KASSERT(*vpp == NULL, ("leaf should be empty")); 8013148Sphk if (error != EJUSTRETURN) 8023148Sphk goto bad; 8033148Sphk /* 8043148Sphk * If creating and at end of pathname, then can consider 8053148Sphk * allowing file to be created. 8063148Sphk */ 80711644Sdg if (rdonly) { 8083148Sphk error = EROFS; 8093148Sphk goto bad; 8103148Sphk } 8113148Sphk /* ASSERT(dvp == ndp->ni_startdir) */ 8123148Sphk if (cnp->cn_flags & SAVESTART) 8133148Sphk VREF(dvp); 814144203Sjeff if ((cnp->cn_flags & LOCKPARENT) == 0) 815144203Sjeff VOP_UNLOCK(dp, 0, td); 8163148Sphk /* 817144203Sjeff * This is a temporary assert to make sure I know what the 818144203Sjeff * behavior here was. 819144203Sjeff */ 820144203Sjeff KASSERT((cnp->cn_flags & (WANTPARENT|LOCKPARENT)) != 0, 821144203Sjeff ("relookup: Unhandled case.")); 822144203Sjeff /* 8233148Sphk * We return with ni_vp NULL to indicate that the entry 8243148Sphk * doesn't currently exist, leaving a pointer to the 8253148Sphk * (possibly locked) directory inode in ndp->ni_dvp. 8263148Sphk */ 8273148Sphk return (0); 8283148Sphk } 829144203Sjeff /* 830144203Sjeff * In the DOTDOT case dp is unlocked, we may have to relock it if 831144203Sjeff * LOCKPARENT is set. Otherwise, unlock the parent. 832144203Sjeff */ 833144203Sjeff if ((cnp->cn_flags & (ISDOTDOT | LOCKPARENT)) == 834144203Sjeff (ISDOTDOT | LOCKPARENT)) 835144203Sjeff vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); 836144203Sjeff else if ((cnp->cn_flags & (ISDOTDOT | LOCKPARENT)) == 0 && dp != *vpp) 837144203Sjeff VOP_UNLOCK(dp, 0, td); 8383148Sphk dp = *vpp; 8393148Sphk 8403148Sphk /* 8413148Sphk * Check for symbolic link 8423148Sphk */ 84342408Seivind KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW), 84442453Seivind ("relookup: symlink found.\n")); 8453148Sphk 8463148Sphk /* 84796755Strhodes * Disallow directory write attempts on read-only filesystems. 8483148Sphk */ 84911644Sdg if (rdonly && 85011644Sdg (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { 85111644Sdg error = EROFS; 85211644Sdg goto bad2; 8533148Sphk } 8543148Sphk /* ASSERT(dvp == ndp->ni_startdir) */ 8553148Sphk if (cnp->cn_flags & SAVESTART) 8563148Sphk VREF(dvp); 85722521Sdyson 8583148Sphk if (!wantparent) 8593148Sphk vrele(dvp); 86032071Sdyson 8613148Sphk if ((cnp->cn_flags & LOCKLEAF) == 0) 86283366Sjulian VOP_UNLOCK(dp, 0, td); 8633148Sphk return (0); 8643148Sphk 8653148Sphkbad2: 866144203Sjeff if (cnp->cn_flags & LOCKPARENT) 86783366Sjulian VOP_UNLOCK(dvp, 0, td); 8683148Sphk vrele(dvp); 8693148Sphkbad: 8703148Sphk vput(dp); 8713148Sphk *vpp = NULL; 8723148Sphk return (error); 8733148Sphk} 874141471Sjhb 875141471Sjhb/* 876144661Sjeff * Free data allocated by namei(); see namei(9) for details. 877144661Sjeff */ 878144661Sjeffvoid 879144661SjeffNDFREE(ndp, flags) 880144661Sjeff struct nameidata *ndp; 881144661Sjeff const u_int flags; 882144661Sjeff{ 883144833Sjeff int unlock_dvp; 884144833Sjeff int unlock_vp; 885144661Sjeff 886144833Sjeff unlock_dvp = 0; 887144833Sjeff unlock_vp = 0; 888144833Sjeff 889144661Sjeff if (!(flags & NDF_NO_FREE_PNBUF) && 890144661Sjeff (ndp->ni_cnd.cn_flags & HASBUF)) { 891144661Sjeff uma_zfree(namei_zone, ndp->ni_cnd.cn_pnbuf); 892144661Sjeff ndp->ni_cnd.cn_flags &= ~HASBUF; 893144661Sjeff } 894144833Sjeff if (!(flags & NDF_NO_VP_UNLOCK) && 895144833Sjeff (ndp->ni_cnd.cn_flags & LOCKLEAF) && ndp->ni_vp) 896144833Sjeff unlock_vp = 1; 897144833Sjeff if (!(flags & NDF_NO_VP_RELE) && ndp->ni_vp) { 898144833Sjeff if (unlock_vp) { 899144833Sjeff vput(ndp->ni_vp); 900144833Sjeff unlock_vp = 0; 901144833Sjeff } else 902144833Sjeff vrele(ndp->ni_vp); 903144833Sjeff ndp->ni_vp = NULL; 904144833Sjeff } 905144833Sjeff if (unlock_vp) 906144833Sjeff VOP_UNLOCK(ndp->ni_vp, 0, ndp->ni_cnd.cn_thread); 907144661Sjeff if (!(flags & NDF_NO_DVP_UNLOCK) && 908144661Sjeff (ndp->ni_cnd.cn_flags & LOCKPARENT) && 909144661Sjeff ndp->ni_dvp != ndp->ni_vp) 910144833Sjeff unlock_dvp = 1; 911144661Sjeff if (!(flags & NDF_NO_DVP_RELE) && 912144661Sjeff (ndp->ni_cnd.cn_flags & (LOCKPARENT|WANTPARENT))) { 913144833Sjeff if (unlock_dvp) { 914144833Sjeff vput(ndp->ni_dvp); 915144833Sjeff unlock_dvp = 0; 916144833Sjeff } else 917144833Sjeff vrele(ndp->ni_dvp); 918144661Sjeff ndp->ni_dvp = NULL; 919144661Sjeff } 920144833Sjeff if (unlock_dvp) 921144833Sjeff VOP_UNLOCK(ndp->ni_dvp, 0, ndp->ni_cnd.cn_thread); 922144661Sjeff if (!(flags & NDF_NO_STARTDIR_RELE) && 923144661Sjeff (ndp->ni_cnd.cn_flags & SAVESTART)) { 924144661Sjeff vrele(ndp->ni_startdir); 925144661Sjeff ndp->ni_startdir = NULL; 926144661Sjeff } 927144661Sjeff} 928144661Sjeff 929144661Sjeff/* 930141471Sjhb * Determine if there is a suitable alternate filename under the specified 931141471Sjhb * prefix for the specified path. If the create flag is set, then the 932141471Sjhb * alternate prefix will be used so long as the parent directory exists. 933141471Sjhb * This is used by the various compatiblity ABIs so that Linux binaries prefer 934141471Sjhb * files under /compat/linux for example. The chosen path (whether under 935141471Sjhb * the prefix or under /) is returned in a kernel malloc'd buffer pointed 936141471Sjhb * to by pathbuf. The caller is responsible for free'ing the buffer from 937141471Sjhb * the M_TEMP bucket if one is returned. 938141471Sjhb */ 939141471Sjhbint 940141471Sjhbkern_alternate_path(struct thread *td, const char *prefix, char *path, 941141471Sjhb enum uio_seg pathseg, char **pathbuf, int create) 942141471Sjhb{ 943141471Sjhb struct nameidata nd, ndroot; 944141471Sjhb char *ptr, *buf, *cp; 945141471Sjhb size_t len, sz; 946141471Sjhb int error; 947141471Sjhb 948141471Sjhb buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 949141471Sjhb *pathbuf = buf; 950141471Sjhb 951141471Sjhb /* Copy the prefix into the new pathname as a starting point. */ 952141471Sjhb len = strlcpy(buf, prefix, MAXPATHLEN); 953141471Sjhb if (len >= MAXPATHLEN) { 954141471Sjhb *pathbuf = NULL; 955141471Sjhb free(buf, M_TEMP); 956141471Sjhb return (EINVAL); 957141471Sjhb } 958141471Sjhb sz = MAXPATHLEN - len; 959141471Sjhb ptr = buf + len; 960141471Sjhb 961141471Sjhb /* Append the filename to the prefix. */ 962141471Sjhb if (pathseg == UIO_SYSSPACE) 963141471Sjhb error = copystr(path, ptr, sz, &len); 964141471Sjhb else 965141471Sjhb error = copyinstr(path, ptr, sz, &len); 966141471Sjhb 967141471Sjhb if (error) { 968141471Sjhb *pathbuf = NULL; 969141471Sjhb free(buf, M_TEMP); 970141471Sjhb return (error); 971141471Sjhb } 972141471Sjhb 973141471Sjhb /* Only use a prefix with absolute pathnames. */ 974141471Sjhb if (*ptr != '/') { 975141471Sjhb error = EINVAL; 976141471Sjhb goto keeporig; 977141471Sjhb } 978141471Sjhb 979141471Sjhb /* XXX: VFS_LOCK_GIANT? */ 980141471Sjhb mtx_lock(&Giant); 981141471Sjhb 982141471Sjhb /* 983141471Sjhb * We know that there is a / somewhere in this pathname. 984141471Sjhb * Search backwards for it, to find the file's parent dir 985141471Sjhb * to see if it exists in the alternate tree. If it does, 986141471Sjhb * and we want to create a file (cflag is set). We don't 987141471Sjhb * need to worry about the root comparison in this case. 988141471Sjhb */ 989141471Sjhb 990141471Sjhb if (create) { 991141471Sjhb for (cp = &ptr[len] - 1; *cp != '/'; cp--); 992141471Sjhb *cp = '\0'; 993141471Sjhb 994141471Sjhb NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td); 995141471Sjhb error = namei(&nd); 996141471Sjhb *cp = '/'; 997141471Sjhb if (error != 0) 998141471Sjhb goto nd_failed; 999141471Sjhb } else { 1000141471Sjhb NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td); 1001141471Sjhb 1002141471Sjhb error = namei(&nd); 1003141471Sjhb if (error != 0) 1004141471Sjhb goto nd_failed; 1005141471Sjhb 1006141471Sjhb /* 1007141471Sjhb * We now compare the vnode of the prefix to the one 1008141471Sjhb * vnode asked. If they resolve to be the same, then we 1009141471Sjhb * ignore the match so that the real root gets used. 1010141471Sjhb * This avoids the problem of traversing "../.." to find the 1011141471Sjhb * root directory and never finding it, because "/" resolves 1012141471Sjhb * to the emulation root directory. This is expensive :-( 1013141471Sjhb */ 1014141471Sjhb NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix, td); 1015141471Sjhb 1016141471Sjhb /* We shouldn't ever get an error from this namei(). */ 1017141471Sjhb error = namei(&ndroot); 1018141471Sjhb if (error == 0) { 1019141471Sjhb if (nd.ni_vp == ndroot.ni_vp) 1020141471Sjhb error = ENOENT; 1021141471Sjhb 1022141471Sjhb NDFREE(&ndroot, NDF_ONLY_PNBUF); 1023141471Sjhb vrele(ndroot.ni_vp); 1024141471Sjhb } 1025141471Sjhb } 1026141471Sjhb 1027141471Sjhb NDFREE(&nd, NDF_ONLY_PNBUF); 1028141471Sjhb vrele(nd.ni_vp); 1029141471Sjhb 1030141471Sjhbnd_failed: 1031141471Sjhb /* XXX: VFS_UNLOCK_GIANT? */ 1032141471Sjhb mtx_unlock(&Giant); 1033141471Sjhb 1034141471Sjhbkeeporig: 1035141471Sjhb /* If there was an error, use the original path name. */ 1036141471Sjhb if (error) 1037141471Sjhb bcopy(ptr, buf, len); 1038141471Sjhb return (error); 1039141471Sjhb} 1040