857 lines
23 KiB
C
857 lines
23 KiB
C
/* $OpenBSD: vfs_lookup.c,v 1.88 2023/01/06 19:08:36 miod Exp $ */
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/* $NetBSD: vfs_lookup.c,v 1.17 1996/02/09 19:00:59 christos Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)vfs_lookup.c 8.6 (Berkeley) 11/21/94
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/syslimits.h>
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#include <sys/namei.h>
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#include <sys/vnode.h>
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#include <sys/lock.h>
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#include <sys/mount.h>
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#include <sys/errno.h>
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#include <sys/pool.h>
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#include <sys/filedesc.h>
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#include <sys/proc.h>
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#include <sys/pledge.h>
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#include <sys/file.h>
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#include <sys/fcntl.h>
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#ifdef KTRACE
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#include <sys/ktrace.h>
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#endif
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int
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component_push(struct componentname *cnp, char *component, size_t len)
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{
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if (cnp->cn_rpi + len + 1 >= MAXPATHLEN)
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return 0;
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if (cnp->cn_rpi > 1)
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cnp->cn_rpbuf[cnp->cn_rpi++] = '/';
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memcpy(cnp->cn_rpbuf + cnp->cn_rpi, component, len);
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cnp->cn_rpi+=len;
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cnp->cn_rpbuf[cnp->cn_rpi] = '\0';
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return 1;
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}
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void
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component_pop(struct componentname *cnp)
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{
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while(cnp->cn_rpi && cnp->cn_rpbuf[cnp->cn_rpi] != '/' )
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cnp->cn_rpi--;
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if (cnp->cn_rpi == 0 && cnp->cn_rpbuf[0] == '/')
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cnp->cn_rpi++;
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cnp->cn_rpbuf[cnp->cn_rpi] = '\0';
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}
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void
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ndinitat(struct nameidata *ndp, u_long op, u_long flags,
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enum uio_seg segflg, int dirfd, const char *namep, struct proc *p)
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{
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memset(ndp, 0, sizeof(*ndp));
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ndp->ni_cnd.cn_nameiop = op;
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ndp->ni_cnd.cn_flags = flags;
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ndp->ni_segflg = segflg;
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ndp->ni_dirfd = dirfd;
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ndp->ni_dirp = namep;
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ndp->ni_cnd.cn_proc = p;
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}
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/*
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* Convert a pathname into a pointer to a vnode.
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*
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* The FOLLOW flag is set when symbolic links are to be followed
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* when they occur at the end of the name translation process.
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* Symbolic links are always followed for all other pathname
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* components other than the last.
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*
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* If the LOCKLEAF flag is set, a locked vnode is returned.
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*
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* The segflg defines whether the name is to be copied from user
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* space or kernel space.
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*
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* Overall outline of namei:
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*
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* copy in name
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* get starting directory
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* while (!done && !error) {
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* call lookup to search path.
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* if symbolic link, massage name in buffer and continue
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* }
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*/
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int
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namei(struct nameidata *ndp)
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{
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struct filedesc *fdp; /* pointer to file descriptor state */
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char *cp; /* pointer into pathname argument */
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struct vnode *dp; /* the directory we are searching */
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struct iovec aiov; /* uio for reading symbolic links */
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struct uio auio;
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int error, linklen;
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struct componentname *cnp = &ndp->ni_cnd;
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struct proc *p = cnp->cn_proc;
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ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_proc->p_ucred;
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#ifdef DIAGNOSTIC
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if (!cnp->cn_cred || !cnp->cn_proc)
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panic ("namei: bad cred/proc");
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if (cnp->cn_nameiop & (~OPMASK))
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panic ("namei: nameiop contaminated with flags");
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if (cnp->cn_flags & OPMASK)
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panic ("namei: flags contaminated with nameiops");
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#endif
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fdp = cnp->cn_proc->p_fd;
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/*
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* Get a buffer for the name to be translated, and copy the
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* name into the buffer.
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*/
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if ((cnp->cn_flags & HASBUF) == 0)
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cnp->cn_pnbuf = pool_get(&namei_pool, PR_WAITOK);
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if (ndp->ni_segflg == UIO_SYSSPACE) {
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ndp->ni_pathlen = strlcpy(cnp->cn_pnbuf, ndp->ni_dirp,
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MAXPATHLEN);
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if (ndp->ni_pathlen >= MAXPATHLEN) {
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error = ENAMETOOLONG;
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} else {
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error = 0;
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ndp->ni_pathlen++; /* ni_pathlen includes NUL */
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}
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} else
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error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
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MAXPATHLEN, &ndp->ni_pathlen);
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/*
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* Fail on null pathnames
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*/
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if (error == 0 && ndp->ni_pathlen == 1)
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error = ENOENT;
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if (error)
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goto fail;
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#ifdef KTRACE
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if (KTRPOINT(cnp->cn_proc, KTR_NAMEI))
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ktrnamei(cnp->cn_proc, cnp->cn_pnbuf);
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#endif
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/*
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* Strip trailing slashes, as requested
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*/
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if (cnp->cn_flags & STRIPSLASHES) {
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char *end = cnp->cn_pnbuf + ndp->ni_pathlen - 2;
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cp = end;
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while (cp >= cnp->cn_pnbuf && (*cp == '/'))
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cp--;
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/* Still some remaining characters in the buffer */
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if (cp >= cnp->cn_pnbuf) {
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ndp->ni_pathlen -= (end - cp);
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*(cp + 1) = '\0';
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}
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}
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ndp->ni_loopcnt = 0;
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/*
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* Get starting point for the translation.
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*/
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if ((ndp->ni_rootdir = fdp->fd_rdir) == NULL ||
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(ndp->ni_cnd.cn_flags & KERNELPATH))
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ndp->ni_rootdir = rootvnode;
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if (ndp->ni_cnd.cn_flags & KERNELPATH) {
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ndp->ni_cnd.cn_flags |= BYPASSUNVEIL;
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} else {
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error = pledge_namei(p, ndp, cnp->cn_pnbuf);
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if (error)
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goto fail;
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}
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/*
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* Check if starting from root directory or current directory.
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*/
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if (cnp->cn_pnbuf[0] == '/') {
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dp = ndp->ni_rootdir;
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vref(dp);
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if (cnp->cn_flags & REALPATH && cnp->cn_rpi == 0) {
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cnp->cn_rpbuf[0] = '/';
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cnp->cn_rpbuf[1] = '\0';
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cnp->cn_rpi = 1;
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}
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} else if (ndp->ni_dirfd == AT_FDCWD) {
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dp = fdp->fd_cdir;
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vref(dp);
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unveil_start_relative(p, ndp, dp);
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unveil_check_component(p, ndp, dp);
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} else {
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struct file *fp = fd_getfile(fdp, ndp->ni_dirfd);
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if (fp == NULL) {
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error = EBADF;
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goto fail;
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}
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dp = (struct vnode *)fp->f_data;
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if (fp->f_type != DTYPE_VNODE || dp->v_type != VDIR) {
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FRELE(fp, p);
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error = ENOTDIR;
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goto fail;
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}
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vref(dp);
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unveil_start_relative(p, ndp, dp);
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unveil_check_component(p, ndp, dp);
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FRELE(fp, p);
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}
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for (;;) {
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if (!dp->v_mount) {
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/* Give up if the directory is no longer mounted */
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vrele(dp);
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error = ENOENT;
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goto fail;
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}
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cnp->cn_nameptr = cnp->cn_pnbuf;
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ndp->ni_startdir = dp;
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if ((error = vfs_lookup(ndp)) != 0)
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goto fail;
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/*
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* If not a symbolic link, return search result.
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*/
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if ((cnp->cn_flags & ISSYMLINK) == 0) {
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if ((error = unveil_check_final(p, ndp))) {
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if ((cnp->cn_flags & LOCKPARENT) &&
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(cnp->cn_flags & ISLASTCN) &&
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(ndp->ni_vp != ndp->ni_dvp))
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vput(ndp->ni_dvp);
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if (ndp->ni_vp) {
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if ((cnp->cn_flags & LOCKLEAF))
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vput(ndp->ni_vp);
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else
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vrele(ndp->ni_vp);
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}
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goto fail;
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}
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if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0)
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pool_put(&namei_pool, cnp->cn_pnbuf);
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else
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cnp->cn_flags |= HASBUF;
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return (0);
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}
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if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
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VOP_UNLOCK(ndp->ni_dvp);
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if (ndp->ni_loopcnt++ >= SYMLOOP_MAX) {
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error = ELOOP;
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break;
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}
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if (ndp->ni_pathlen > 1)
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cp = pool_get(&namei_pool, PR_WAITOK);
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else
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cp = cnp->cn_pnbuf;
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aiov.iov_base = cp;
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aiov.iov_len = MAXPATHLEN;
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auio.uio_iov = &aiov;
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auio.uio_iovcnt = 1;
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auio.uio_offset = 0;
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auio.uio_rw = UIO_READ;
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auio.uio_segflg = UIO_SYSSPACE;
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auio.uio_procp = cnp->cn_proc;
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auio.uio_resid = MAXPATHLEN;
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error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
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if (error) {
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badlink:
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if (ndp->ni_pathlen > 1)
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pool_put(&namei_pool, cp);
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break;
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}
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linklen = MAXPATHLEN - auio.uio_resid;
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if (linklen == 0) {
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error = ENOENT;
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goto badlink;
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}
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if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
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error = ENAMETOOLONG;
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goto badlink;
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}
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if (ndp->ni_pathlen > 1) {
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memcpy(cp + linklen, ndp->ni_next, ndp->ni_pathlen);
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pool_put(&namei_pool, cnp->cn_pnbuf);
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cnp->cn_pnbuf = cp;
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} else
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cnp->cn_pnbuf[linklen] = '\0';
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ndp->ni_pathlen += linklen;
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vput(ndp->ni_vp);
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dp = ndp->ni_dvp;
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/*
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* Check if root directory should replace current directory.
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*/
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if (cnp->cn_pnbuf[0] == '/') {
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vrele(dp);
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dp = ndp->ni_rootdir;
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vref(dp);
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ndp->ni_unveil_match = NULL;
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unveil_check_component(p, ndp, dp);
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if (cnp->cn_flags & REALPATH) {
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cnp->cn_rpbuf[0] = '/';
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cnp->cn_rpbuf[1] = '\0';
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cnp->cn_rpi = 1;
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}
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} else if (cnp->cn_flags & REALPATH) {
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component_pop(cnp);
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}
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}
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vrele(ndp->ni_dvp);
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vput(ndp->ni_vp);
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fail:
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pool_put(&namei_pool, cnp->cn_pnbuf);
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ndp->ni_vp = NULL;
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return (error);
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}
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/*
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* Search a pathname.
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* This is a very central and rather complicated routine.
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*
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* The pathname is pointed to by ni_cnd.cn_nameptr and is of length
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* ni_pathlen. The starting directory is taken from ni_startdir. The
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* pathname is descended until done, or a symbolic link is encountered.
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* If the path is completed the flag ISLASTCN is set in ni_cnd.cn_flags.
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* If a symbolic link need interpretation is encountered, the flag ISSYMLINK
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* is set in ni_cnd.cn_flags.
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*
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* The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
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* whether the name is to be looked up, created, renamed, or deleted.
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* When CREATE, RENAME, or DELETE is specified, information usable in
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* creating, renaming, or deleting a directory entry may be calculated.
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* If flag has LOCKPARENT or'ed into it, the parent directory is returned
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* locked. If flag has WANTPARENT or'ed into it, the parent directory is
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* returned unlocked. Otherwise the parent directory is not returned. If
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* the target of the pathname exists and LOCKLEAF is or'ed into the flag
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* the target is returned locked, otherwise it is returned unlocked.
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* When creating or renaming and LOCKPARENT is specified, the target may not
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* be ".". When deleting and LOCKPARENT is specified, the target may be ".".
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*
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* Overall outline of lookup:
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*
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* dirloop:
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* identify next component of name at ndp->ni_ptr
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* handle degenerate case where name is null string
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* if .. and crossing mount points and on mounted filesys, find parent
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* call VOP_LOOKUP routine for next component name
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* directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
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* component vnode returned in ni_vp (if it exists), locked.
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* if result vnode is mounted on and crossing mount points,
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* find mounted on vnode
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* if more components of name, do next level at dirloop
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* return the answer in ni_vp, locked if LOCKLEAF set
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* if LOCKPARENT set, return locked parent in ni_dvp
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* if WANTPARENT set, return unlocked parent in ni_dvp
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*/
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int
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vfs_lookup(struct nameidata *ndp)
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{
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char *cp; /* pointer into pathname argument */
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struct vnode *dp = NULL; /* the directory we are searching */
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struct vnode *tdp; /* saved dp */
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struct mount *mp; /* mount table entry */
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int docache; /* == 0 do not cache last component */
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int wantparent; /* 1 => wantparent or lockparent flag */
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int rdonly; /* lookup read-only flag bit */
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int error = 0;
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int dpunlocked = 0; /* dp has already been unlocked */
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int slashes;
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struct componentname *cnp = &ndp->ni_cnd;
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/*
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* Setup: break out flag bits into variables.
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*/
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wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
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docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
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if (cnp->cn_nameiop == DELETE ||
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(wantparent && cnp->cn_nameiop != CREATE))
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docache = 0;
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rdonly = cnp->cn_flags & RDONLY;
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ndp->ni_dvp = NULL;
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cnp->cn_flags &= ~ISSYMLINK;
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dp = ndp->ni_startdir;
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ndp->ni_startdir = NULLVP;
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vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
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/*
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* If we have a leading string of slashes, remove them, and just make
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* sure the current node is a directory.
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*/
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cp = cnp->cn_nameptr;
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if (*cp == '/') {
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do {
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cp++;
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} while (*cp == '/');
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ndp->ni_pathlen -= cp - cnp->cn_nameptr;
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cnp->cn_nameptr = cp;
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if (dp->v_type != VDIR) {
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error = ENOTDIR;
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goto bad;
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}
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/*
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* If we've exhausted the path name, then just return the
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* current node. If the caller requested the parent node (i.e.
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* it's a CREATE, DELETE, or RENAME), and we don't have one
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* (because this is the root directory), then we must fail.
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*/
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if (cnp->cn_nameptr[0] == '\0') {
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if (ndp->ni_dvp == NULL && wantparent) {
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error = EISDIR;
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goto bad;
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}
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ndp->ni_vp = dp;
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cnp->cn_flags |= ISLASTCN;
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goto terminal;
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}
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}
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dirloop:
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/*
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* Search a new directory.
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*
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* The last component of the filename is left accessible via
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* cnp->cn_nameptr for callers that need the name. Callers needing
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* the name set the SAVENAME flag. When done, they assume
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* responsibility for freeing the pathname buffer.
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*/
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cnp->cn_consume = 0;
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/* XXX: Figure out the length of the last component. */
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cp = cnp->cn_nameptr;
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while (*cp && (*cp != '/'))
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cp++;
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cnp->cn_namelen = cp - cnp->cn_nameptr;
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if (cnp->cn_namelen > NAME_MAX) {
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error = ENAMETOOLONG;
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goto bad;
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}
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#ifdef NAMEI_DIAGNOSTIC
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{ char c = *cp;
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*cp = '\0';
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printf("{%s}: ", cnp->cn_nameptr);
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*cp = c; }
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|
#endif
|
|
if (cnp->cn_flags & REALPATH) {
|
|
size_t len = cp - cnp->cn_nameptr;
|
|
if (len == 2 && cnp->cn_nameptr[0] == '.' &&
|
|
cnp->cn_nameptr[1] == '.')
|
|
component_pop(cnp);
|
|
else if (!(len == 1 && cnp->cn_nameptr[0] == '.')) {
|
|
if (!component_push(cnp, cnp->cn_nameptr, len)) {
|
|
error = ENAMETOOLONG;
|
|
goto bad;
|
|
}
|
|
}
|
|
}
|
|
|
|
ndp->ni_pathlen -= cnp->cn_namelen;
|
|
ndp->ni_next = cp;
|
|
/*
|
|
* If this component is followed by a slash, then move the pointer to
|
|
* the next component forward, and remember that this component must be
|
|
* a directory.
|
|
*/
|
|
if (*cp == '/') {
|
|
do {
|
|
cp++;
|
|
} while (*cp == '/');
|
|
slashes = cp - ndp->ni_next;
|
|
ndp->ni_pathlen -= slashes;
|
|
ndp->ni_next = cp;
|
|
cnp->cn_flags |= REQUIREDIR;
|
|
} else {
|
|
slashes = 0;
|
|
cnp->cn_flags &= ~REQUIREDIR;
|
|
}
|
|
/*
|
|
* We do special processing on the last component, whether or not it's
|
|
* a directory. Cache all intervening lookups, but not the final one.
|
|
*/
|
|
if (*cp == '\0') {
|
|
if (docache)
|
|
cnp->cn_flags |= MAKEENTRY;
|
|
else
|
|
cnp->cn_flags &= ~MAKEENTRY;
|
|
cnp->cn_flags |= ISLASTCN;
|
|
} else {
|
|
cnp->cn_flags |= MAKEENTRY;
|
|
cnp->cn_flags &= ~ISLASTCN;
|
|
}
|
|
if (cnp->cn_namelen == 2 &&
|
|
cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
|
|
cnp->cn_flags |= ISDOTDOT;
|
|
else
|
|
cnp->cn_flags &= ~ISDOTDOT;
|
|
|
|
/*
|
|
* Handle "..": two special cases.
|
|
* 1. If at root directory (e.g. after chroot)
|
|
* or at absolute root directory
|
|
* then ignore it so can't get out.
|
|
* 2. If this vnode is the root of a mounted
|
|
* filesystem, then replace it with the
|
|
* vnode which was mounted on so we take the
|
|
* .. in the other file system.
|
|
*/
|
|
if (cnp->cn_flags & ISDOTDOT) {
|
|
for (;;) {
|
|
if (dp == ndp->ni_rootdir || dp == rootvnode) {
|
|
ndp->ni_dvp = dp;
|
|
ndp->ni_vp = dp;
|
|
vref(dp);
|
|
ndp->ni_unveil_match = NULL;
|
|
goto nextname;
|
|
}
|
|
if ((dp->v_flag & VROOT) == 0 ||
|
|
(cnp->cn_flags & NOCROSSMOUNT))
|
|
break;
|
|
tdp = dp;
|
|
dp = dp->v_mount->mnt_vnodecovered;
|
|
vput(tdp);
|
|
vref(dp);
|
|
unveil_check_component(curproc, ndp, dp);
|
|
vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We now have a segment name to search for, and a directory to search.
|
|
*/
|
|
ndp->ni_dvp = dp;
|
|
ndp->ni_vp = NULL;
|
|
cnp->cn_flags &= ~PDIRUNLOCK;
|
|
unveil_check_component(curproc, ndp, dp);
|
|
|
|
if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) {
|
|
#ifdef DIAGNOSTIC
|
|
if (ndp->ni_vp != NULL)
|
|
panic("leaf should be empty");
|
|
#endif
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
printf("not found\n");
|
|
#endif
|
|
/*
|
|
* Allow for unveiling a file in a directory which we cannot
|
|
* create ourselves.
|
|
*/
|
|
if (ndp->ni_pledge == PLEDGE_UNVEIL &&
|
|
(error == EPERM || error == EACCES || error == EROFS))
|
|
error = EJUSTRETURN;
|
|
|
|
if (error != EJUSTRETURN)
|
|
goto bad;
|
|
/*
|
|
* If this was not the last component, or there were trailing
|
|
* slashes, then the name must exist.
|
|
*/
|
|
if (cnp->cn_flags & REQUIREDIR) {
|
|
error = ENOENT;
|
|
goto bad;
|
|
}
|
|
/*
|
|
* If creating and at end of pathname, then can consider
|
|
* allowing file to be created. Check for a read only
|
|
* filesystem and disallow this unless we are unveil'ing
|
|
*/
|
|
if (ndp->ni_pledge != PLEDGE_UNVEIL && (rdonly ||
|
|
(ndp->ni_dvp->v_mount->mnt_flag & MNT_RDONLY))) {
|
|
error = EROFS;
|
|
goto bad;
|
|
}
|
|
/*
|
|
* We return with ni_vp NULL to indicate that the entry
|
|
* doesn't currently exist, leaving a pointer to the
|
|
* (possibly locked) directory inode in ndp->ni_dvp.
|
|
*/
|
|
if (cnp->cn_flags & SAVESTART) {
|
|
ndp->ni_startdir = ndp->ni_dvp;
|
|
vref(ndp->ni_startdir);
|
|
}
|
|
return (0);
|
|
}
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
printf("found\n");
|
|
#endif
|
|
|
|
/*
|
|
* Take into account any additional components consumed by the
|
|
* underlying filesystem. This will include any trailing slashes after
|
|
* the last component consumed.
|
|
*/
|
|
if (cnp->cn_consume > 0) {
|
|
if (cnp->cn_consume >= slashes) {
|
|
cnp->cn_flags &= ~REQUIREDIR;
|
|
}
|
|
|
|
ndp->ni_pathlen -= cnp->cn_consume - slashes;
|
|
ndp->ni_next += cnp->cn_consume - slashes;
|
|
cnp->cn_consume = 0;
|
|
if (ndp->ni_next[0] == '\0')
|
|
cnp->cn_flags |= ISLASTCN;
|
|
}
|
|
|
|
dp = ndp->ni_vp;
|
|
/*
|
|
* Check to see if the vnode has been mounted on;
|
|
* if so find the root of the mounted file system.
|
|
*/
|
|
while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
|
|
(cnp->cn_flags & NOCROSSMOUNT) == 0) {
|
|
if (vfs_busy(mp, VB_READ|VB_WAIT))
|
|
continue;
|
|
VOP_UNLOCK(dp);
|
|
error = VFS_ROOT(mp, &tdp);
|
|
vfs_unbusy(mp);
|
|
if (error) {
|
|
dpunlocked = 1;
|
|
goto bad2;
|
|
}
|
|
vrele(dp);
|
|
ndp->ni_vp = dp = tdp;
|
|
}
|
|
|
|
/*
|
|
* Check for symbolic link. Back up over any slashes that we skipped,
|
|
* as we will need them again.
|
|
*/
|
|
if ((dp->v_type == VLNK) && (cnp->cn_flags & (FOLLOW|REQUIREDIR))) {
|
|
ndp->ni_pathlen += slashes;
|
|
ndp->ni_next -= slashes;
|
|
cnp->cn_flags |= ISSYMLINK;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Check for directory, if the component was followed by a series of
|
|
* slashes.
|
|
*/
|
|
if ((dp->v_type != VDIR) && (cnp->cn_flags & REQUIREDIR)) {
|
|
error = ENOTDIR;
|
|
goto bad2;
|
|
}
|
|
|
|
nextname:
|
|
/*
|
|
* Not a symbolic link. If this was not the last component, then
|
|
* continue at the next component, else return.
|
|
*/
|
|
if (!(cnp->cn_flags & ISLASTCN)) {
|
|
cnp->cn_nameptr = ndp->ni_next;
|
|
vrele(ndp->ni_dvp);
|
|
goto dirloop;
|
|
}
|
|
|
|
terminal:
|
|
/*
|
|
* Check for read-only file systems.
|
|
*/
|
|
if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) {
|
|
/*
|
|
* Disallow directory write attempts on read-only
|
|
* file systems.
|
|
*/
|
|
if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) ||
|
|
(wantparent &&
|
|
(ndp->ni_dvp->v_mount->mnt_flag & MNT_RDONLY))) {
|
|
error = EROFS;
|
|
goto bad2;
|
|
}
|
|
}
|
|
if (ndp->ni_dvp != NULL) {
|
|
if (cnp->cn_flags & SAVESTART) {
|
|
ndp->ni_startdir = ndp->ni_dvp;
|
|
vref(ndp->ni_startdir);
|
|
}
|
|
if (!wantparent)
|
|
vrele(ndp->ni_dvp);
|
|
}
|
|
if ((cnp->cn_flags & LOCKLEAF) == 0)
|
|
VOP_UNLOCK(dp);
|
|
return (0);
|
|
|
|
bad2:
|
|
if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN) &&
|
|
((cnp->cn_flags & PDIRUNLOCK) == 0))
|
|
VOP_UNLOCK(ndp->ni_dvp);
|
|
vrele(ndp->ni_dvp);
|
|
bad:
|
|
if (dpunlocked)
|
|
vrele(dp);
|
|
else
|
|
vput(dp);
|
|
ndp->ni_vp = NULL;
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Reacquire a path name component.
|
|
*/
|
|
int
|
|
vfs_relookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
|
|
{
|
|
struct vnode *dp = NULL; /* the directory we are searching */
|
|
int wantparent; /* 1 => wantparent or lockparent flag */
|
|
int rdonly; /* lookup read-only flag bit */
|
|
int error = 0;
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
char *cp; /* DEBUG: check name ptr/len */
|
|
#endif
|
|
|
|
/*
|
|
* Setup: break out flag bits into variables.
|
|
*/
|
|
wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
|
|
rdonly = cnp->cn_flags & RDONLY;
|
|
cnp->cn_flags &= ~ISSYMLINK;
|
|
dp = dvp;
|
|
vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
|
|
|
|
/* dirloop: */
|
|
/*
|
|
* Search a new directory.
|
|
*
|
|
* The last component of the filename is left accessible via
|
|
* cnp->cn_nameptr for callers that need the name. Callers needing
|
|
* the name set the SAVENAME flag. When done, they assume
|
|
* responsibility for freeing the pathname buffer.
|
|
*/
|
|
|
|
#ifdef NAMEI_DIAGNOSTIC
|
|
/* XXX: Figure out the length of the last component. */
|
|
cp = cnp->cn_nameptr;
|
|
while (*cp && (*cp != '/')) {
|
|
cp++;
|
|
}
|
|
if (cnp->cn_namelen != cp - cnp->cn_nameptr)
|
|
panic("relookup: bad len");
|
|
if (*cp != 0)
|
|
panic("relookup: not last component");
|
|
printf("{%s}: ", cnp->cn_nameptr);
|
|
#endif
|
|
|
|
/*
|
|
* Check for degenerate name (e.g. / or "")
|
|
* which is a way of talking about a directory,
|
|
* e.g. like "/." or ".".
|
|
*/
|
|
if (cnp->cn_nameptr[0] == '\0')
|
|
panic("relookup: null name");
|
|
|
|
if (cnp->cn_flags & ISDOTDOT)
|
|
panic ("relookup: lookup on dot-dot");
|
|
|
|
/*
|
|
* We now have a segment name to search for, and a directory to search.
|
|
*/
|
|
if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) {
|
|
#ifdef DIAGNOSTIC
|
|
if (*vpp != NULL)
|
|
panic("leaf should be empty");
|
|
#endif
|
|
if (error != EJUSTRETURN)
|
|
goto bad;
|
|
/*
|
|
* If creating and at end of pathname, then can consider
|
|
* allowing file to be created.
|
|
*/
|
|
if (rdonly || (dvp->v_mount->mnt_flag & MNT_RDONLY)) {
|
|
error = EROFS;
|
|
goto bad;
|
|
}
|
|
/* ASSERT(dvp == ndp->ni_startdir) */
|
|
if (cnp->cn_flags & SAVESTART)
|
|
vref(dvp);
|
|
/*
|
|
* We return with ni_vp NULL to indicate that the entry
|
|
* doesn't currently exist, leaving a pointer to the
|
|
* (possibly locked) directory inode in ndp->ni_dvp.
|
|
*/
|
|
return (0);
|
|
}
|
|
dp = *vpp;
|
|
|
|
#ifdef DIAGNOSTIC
|
|
/*
|
|
* Check for symbolic link
|
|
*/
|
|
if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW))
|
|
panic ("relookup: symlink found.");
|
|
#endif
|
|
|
|
/*
|
|
* Check for read-only file systems.
|
|
*/
|
|
if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) {
|
|
/*
|
|
* Disallow directory write attempts on read-only
|
|
* file systems.
|
|
*/
|
|
if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) ||
|
|
(wantparent &&
|
|
(dvp->v_mount->mnt_flag & MNT_RDONLY))) {
|
|
error = EROFS;
|
|
goto bad2;
|
|
}
|
|
}
|
|
/* ASSERT(dvp == ndp->ni_startdir) */
|
|
if (cnp->cn_flags & SAVESTART)
|
|
vref(dvp);
|
|
if (!wantparent)
|
|
vrele(dvp);
|
|
if ((cnp->cn_flags & LOCKLEAF) == 0)
|
|
VOP_UNLOCK(dp);
|
|
return (0);
|
|
|
|
bad2:
|
|
if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
|
|
VOP_UNLOCK(dvp);
|
|
vrele(dvp);
|
|
bad:
|
|
vput(dp);
|
|
*vpp = NULL;
|
|
return (error);
|
|
}
|
|
|
|
|