1079 lines
32 KiB
C
1079 lines
32 KiB
C
/*
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* modified for Lites 1.1
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*
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* Aug 1995, Godmar Back (gback@cs.utah.edu)
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* University of Utah, Department of Computer Science
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*/
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/*
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* Copyright (c) 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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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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* @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94
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*/
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#if !defined(__FreeBSD__)
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#include "diagnostic.h"
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#endif
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/namei.h>
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#include <sys/buf.h>
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#include <sys/file.h>
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#include <sys/mount.h>
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#include <sys/vnode.h>
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#include <sys/malloc.h>
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#include <sys/dirent.h>
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#include <ufs/ufs/quota.h>
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#include <ufs/ufs/inode.h>
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#include <ufs/ufs/dir.h>
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#include <ufs/ufs/ufsmount.h>
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#include <ufs/ufs/ufs_extern.h>
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#include <gnu/ext2fs/ext2_extern.h>
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#include <gnu/ext2fs/ext2_fs.h>
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#include <gnu/ext2fs/ext2_fs_sb.h>
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/*
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DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512)
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while it is the native blocksize in ext2fs - thus, a #define
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is no longer appropriate
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*/
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#undef DIRBLKSIZ
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extern int dirchk;
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static void ext2_dirconv2ffs __P((struct ext2_dir_entry *e2dir,
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struct dirent *ffsdir));
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static int ext2_dirbadentry __P((struct vnode *dp,
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struct ext2_dir_entry *de,
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int entryoffsetinblock));
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/*
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* the problem that is tackled below is the fact that FFS
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* includes the terminating zero on disk while EXT2FS doesn't
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* this implies that we need to introduce some padding.
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* For instance, a filename "sbin" has normally a reclen 12
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* in EXT2, but 16 in FFS.
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* This reminds me of that Pepsi commercial: 'Kid saved a lousy nine cents...'
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* If it wasn't for that, the complete ufs code for directories would
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* have worked w/o changes (except for the difference in DIRBLKSIZ)
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*/
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static void
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ext2_dirconv2ffs( e2dir, ffsdir)
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struct ext2_dir_entry *e2dir;
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struct dirent *ffsdir;
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{
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struct dirent de;
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bzero(&de, sizeof(struct dirent));
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de.d_fileno = e2dir->inode;
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de.d_namlen = e2dir->name_len;
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#ifndef NO_HARDWIRED_CONSTANTS
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if(e2dir->name_len + 8 == e2dir->rec_len)
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de.d_reclen += 4;
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de.d_type = DT_UNKNOWN; /* don't know more here */
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strncpy(de.d_name, e2dir->name, e2dir->name_len);
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de.d_name[de.d_namlen] = '\0';
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/* Godmar thinks: since e2dir->rec_len can be big and means
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nothing anyway, we compute our own reclen according to what
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we think is right
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*/
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de.d_reclen = (de.d_namlen+8+1+3) & ~3;
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bcopy(&de, ffsdir, de.d_reclen);
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#endif
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#if 0
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printf("dirconv: ino %d rec old %d rec new %d nam %d name %s\n",
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ffsdir->d_fileno, e2dir->rec_len, ffsdir->d_reclen,
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ffsdir->d_namlen, ffsdir->d_name);
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#endif
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}
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/*
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* Vnode op for reading directories.
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*
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* The routine below assumes that the on-disk format of a directory
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* is the same as that defined by <sys/dirent.h>. If the on-disk
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* format changes, then it will be necessary to do a conversion
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* from the on-disk format that read returns to the format defined
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* by <sys/dirent.h>.
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*/
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/*
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* this is exactly what we do here - the problem is that the conversion
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* will blow up some entries by four bytes, so it can't be done in place.
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* This is too bad. Right now the conversion is done entry by entry, the
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* converted entry is sent via uiomove.
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*
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* XXX allocate a buffer, convert as many entries as possible, then send
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* the whole buffer to uiomove
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*/
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int
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ext2_readdir(ap)
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struct vop_readdir_args /* {
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struct vnode *a_vp;
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struct uio *a_uio;
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struct ucred *a_cred;
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} */ *ap;
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{
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register struct uio *uio = ap->a_uio;
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int count, error;
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struct ext2_dir_entry *edp, *dp;
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struct dirent dstdp;
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struct uio auio;
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struct iovec aiov;
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caddr_t dirbuf;
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int readcnt;
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u_quad_t startoffset = uio->uio_offset;
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count = uio->uio_resid; /* legyenek boldogok akik akarnak ... */
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uio->uio_resid = count;
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uio->uio_iov->iov_len = count;
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#if 0
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printf("ext2_readdir called uio->uio_offset %d uio->uio_resid %d count %d \n",
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(int)uio->uio_offset, (int)uio->uio_resid, (int)count);
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#endif
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auio = *uio;
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auio.uio_iov = &aiov;
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auio.uio_iovcnt = 1;
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auio.uio_segflg = UIO_SYSSPACE;
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aiov.iov_len = count;
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MALLOC(dirbuf, caddr_t, count, M_TEMP, M_WAITOK);
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aiov.iov_base = dirbuf;
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error = VOP_READ(ap->a_vp, &auio, 0, ap->a_cred);
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if (error == 0) {
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readcnt = count - auio.uio_resid;
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edp = (struct ext2_dir_entry *)&dirbuf[readcnt];
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for (dp = (struct ext2_dir_entry *)dirbuf;
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!error && uio->uio_resid > 0 && dp < edp; ) {
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ext2_dirconv2ffs(dp, &dstdp);
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if (dp->rec_len > 0) {
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if(dstdp.d_reclen <= uio->uio_resid) {
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/* advance dp */
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dp = (struct ext2_dir_entry *)
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((char *)dp + dp->rec_len);
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error =
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uiomove((caddr_t)&dstdp,
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dstdp.d_reclen, uio);
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} else
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break;
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} else {
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error = EIO;
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break;
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}
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}
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/* we need to correct uio_offset */
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uio->uio_offset = startoffset + (caddr_t)dp - dirbuf;
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}
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FREE(dirbuf, M_TEMP);
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return (error);
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}
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/*
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* Convert a component of a pathname into a pointer to a locked inode.
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* This is a very central and rather complicated routine.
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* If the file system is not maintained in a strict tree hierarchy,
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* this can result in a deadlock situation (see comments in code below).
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*
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* The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
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* on 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 and the target of the pathname
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* exists, lookup returns both the target and its parent directory locked.
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* When creating or renaming and LOCKPARENT is specified, the target may
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* not be ".". When deleting and LOCKPARENT is specified, the target may
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* be "."., but the caller must check to ensure it does an vrele and vput
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* instead of two vputs.
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*
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* Overall outline of ufs_lookup:
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*
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* check accessibility of directory
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* look for name in cache, if found, then if at end of path
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* and deleting or creating, drop it, else return name
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* search for name in directory, to found or notfound
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* notfound:
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* if creating, return locked directory, leaving info on available slots
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* else return error
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* found:
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* if at end of path and deleting, return information to allow delete
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* if at end of path and rewriting (RENAME and LOCKPARENT), lock target
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* inode and return info to allow rewrite
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* if not at end, add name to cache; if at end and neither creating
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* nor deleting, add name to cache
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*/
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int
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ext2_lookup(ap)
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struct vop_lookup_args /* {
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struct vnode *a_dvp;
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struct vnode **a_vpp;
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struct componentname *a_cnp;
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} */ *ap;
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{
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register struct vnode *vdp; /* vnode for directory being searched */
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register struct inode *dp; /* inode for directory being searched */
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struct buf *bp; /* a buffer of directory entries */
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register struct ext2_dir_entry *ep; /* the current directory entry */
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int entryoffsetinblock; /* offset of ep in bp's buffer */
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enum {NONE, COMPACT, FOUND} slotstatus;
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doff_t slotoffset; /* offset of area with free space */
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int slotsize; /* size of area at slotoffset */
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int slotfreespace; /* amount of space free in slot */
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int slotneeded; /* size of the entry we're seeking */
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int numdirpasses; /* strategy for directory search */
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doff_t endsearch; /* offset to end directory search */
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doff_t prevoff; /* prev entry dp->i_offset */
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struct vnode *pdp; /* saved dp during symlink work */
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struct vnode *tdp; /* returned by VFS_VGET */
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doff_t enduseful; /* pointer past last used dir slot */
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u_long bmask; /* block offset mask */
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int lockparent; /* 1 => lockparent flag is set */
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int wantparent; /* 1 => wantparent or lockparent flag */
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int namlen, error;
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struct vnode **vpp = ap->a_vpp;
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struct componentname *cnp = ap->a_cnp;
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struct ucred *cred = cnp->cn_cred;
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int flags = cnp->cn_flags;
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int nameiop = cnp->cn_nameiop;
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struct proc *p = cnp->cn_proc;
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int DIRBLKSIZ = VTOI(ap->a_dvp)->i_e2fs->s_blocksize;
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bp = NULL;
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slotoffset = -1;
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*vpp = NULL;
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vdp = ap->a_dvp;
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dp = VTOI(vdp);
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lockparent = flags & LOCKPARENT;
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wantparent = flags & (LOCKPARENT|WANTPARENT);
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/*
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* Check accessiblity of directory.
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*/
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if ((dp->i_mode & IFMT) != IFDIR)
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return (ENOTDIR);
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if (error = VOP_ACCESS(vdp, VEXEC, cred, cnp->cn_proc))
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return (error);
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/*
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* We now have a segment name to search for, and a directory to search.
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*
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* Before tediously performing a linear scan of the directory,
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* check the name cache to see if the directory/name pair
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* we are looking for is known already.
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*/
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if (error = cache_lookup(vdp, vpp, cnp)) {
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int vpid; /* capability number of vnode */
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if (error == ENOENT)
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return (error);
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/*
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* Get the next vnode in the path.
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* See comment below starting `Step through' for
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* an explaination of the locking protocol.
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*/
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pdp = vdp;
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dp = VTOI(*vpp);
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vdp = *vpp;
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vpid = vdp->v_id;
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if (pdp == vdp) { /* lookup on "." */
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VREF(vdp);
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error = 0;
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} else if (flags & ISDOTDOT) {
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VOP_UNLOCK(pdp, 0, p);
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error = vget(vdp, LK_EXCLUSIVE, p);
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if (!error && lockparent && (flags & ISLASTCN))
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error = vn_lock(pdp, LK_EXCLUSIVE, p);
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} else {
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error = vget(vdp, LK_EXCLUSIVE, p);
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if (!lockparent || error || !(flags & ISLASTCN))
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VOP_UNLOCK(pdp, 0, p);
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}
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/*
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* Check that the capability number did not change
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* while we were waiting for the lock.
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*/
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if (!error) {
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if (vpid == vdp->v_id)
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return (0);
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vput(vdp);
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if (lockparent && pdp != vdp && (flags & ISLASTCN))
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VOP_UNLOCK(pdp, 0, p);
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}
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if (error = vn_lock(pdp, LK_EXCLUSIVE, p))
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return (error);
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vdp = pdp;
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dp = VTOI(pdp);
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*vpp = NULL;
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}
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/*
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* Suppress search for slots unless creating
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* file and at end of pathname, in which case
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* we watch for a place to put the new file in
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* case it doesn't already exist.
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*/
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slotstatus = FOUND;
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slotfreespace = slotsize = slotneeded = 0;
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if ((nameiop == CREATE || nameiop == RENAME) &&
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(flags & ISLASTCN)) {
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slotstatus = NONE;
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slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen);
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/* was
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slotneeded = (sizeof(struct direct) - MAXNAMLEN +
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cnp->cn_namelen + 3) &~ 3; */
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}
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/*
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* If there is cached information on a previous search of
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* this directory, pick up where we last left off.
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* We cache only lookups as these are the most common
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* and have the greatest payoff. Caching CREATE has little
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* benefit as it usually must search the entire directory
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* to determine that the entry does not exist. Caching the
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* location of the last DELETE or RENAME has not reduced
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* profiling time and hence has been removed in the interest
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* of simplicity.
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*/
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bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
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if (nameiop != LOOKUP || dp->i_diroff == 0 ||
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dp->i_diroff > dp->i_size) {
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entryoffsetinblock = 0;
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dp->i_offset = 0;
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numdirpasses = 1;
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} else {
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dp->i_offset = dp->i_diroff;
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if ((entryoffsetinblock = dp->i_offset & bmask) &&
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(error = VOP_BLKATOFF(vdp, (off_t)dp->i_offset, NULL, &bp)))
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return (error);
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numdirpasses = 2;
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nchstats.ncs_2passes++;
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}
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prevoff = dp->i_offset;
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endsearch = roundup(dp->i_size, DIRBLKSIZ);
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enduseful = 0;
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searchloop:
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while (dp->i_offset < endsearch) {
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/*
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* If necessary, get the next directory block.
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*/
|
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if ((dp->i_offset & bmask) == 0) {
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if (bp != NULL)
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brelse(bp);
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if (error =
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VOP_BLKATOFF(vdp, (off_t)dp->i_offset, NULL, &bp))
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return (error);
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entryoffsetinblock = 0;
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}
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/*
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* If still looking for a slot, and at a DIRBLKSIZE
|
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* boundary, have to start looking for free space again.
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*/
|
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if (slotstatus == NONE &&
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(entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
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slotoffset = -1;
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slotfreespace = 0;
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}
|
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/*
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* Get pointer to next entry.
|
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* Full validation checks are slow, so we only check
|
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* enough to insure forward progress through the
|
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* directory. Complete checks can be run by patching
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* "dirchk" to be true.
|
|
*/
|
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ep = (struct ext2_dir_entry *)
|
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((char *)bp->b_data + entryoffsetinblock);
|
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if (ep->rec_len == 0 ||
|
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(dirchk && ext2_dirbadentry(vdp, ep, entryoffsetinblock))) {
|
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int i;
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ufs_dirbad(dp, dp->i_offset, "mangled entry");
|
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i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
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dp->i_offset += i;
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entryoffsetinblock += i;
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continue;
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}
|
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|
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/*
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* If an appropriate sized slot has not yet been found,
|
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* check to see if one is available. Also accumulate space
|
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* in the current block so that we can determine if
|
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* compaction is viable.
|
|
*/
|
|
if (slotstatus != FOUND) {
|
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int size = ep->rec_len;
|
|
|
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if (ep->inode != 0)
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size -= EXT2_DIR_REC_LEN(ep->name_len);
|
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if (size > 0) {
|
|
if (size >= slotneeded) {
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slotstatus = FOUND;
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slotoffset = dp->i_offset;
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slotsize = ep->rec_len;
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} else if (slotstatus == NONE) {
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slotfreespace += size;
|
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if (slotoffset == -1)
|
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slotoffset = dp->i_offset;
|
|
if (slotfreespace >= slotneeded) {
|
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slotstatus = COMPACT;
|
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slotsize = dp->i_offset +
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ep->rec_len - slotoffset;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
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/*
|
|
* Check for a name match.
|
|
*/
|
|
if (ep->inode) {
|
|
namlen = ep->name_len;
|
|
if (namlen == cnp->cn_namelen &&
|
|
!bcmp(cnp->cn_nameptr, ep->name,
|
|
(unsigned)namlen)) {
|
|
/*
|
|
* Save directory entry's inode number and
|
|
* reclen in ndp->ni_ufs area, and release
|
|
* directory buffer.
|
|
*/
|
|
dp->i_ino = ep->inode;
|
|
dp->i_reclen = ep->rec_len;
|
|
brelse(bp);
|
|
goto found;
|
|
}
|
|
}
|
|
prevoff = dp->i_offset;
|
|
dp->i_offset += ep->rec_len;
|
|
entryoffsetinblock += ep->rec_len;
|
|
if (ep->inode)
|
|
enduseful = dp->i_offset;
|
|
}
|
|
/* notfound: */
|
|
/*
|
|
* If we started in the middle of the directory and failed
|
|
* to find our target, we must check the beginning as well.
|
|
*/
|
|
if (numdirpasses == 2) {
|
|
numdirpasses--;
|
|
dp->i_offset = 0;
|
|
endsearch = dp->i_diroff;
|
|
goto searchloop;
|
|
}
|
|
if (bp != NULL)
|
|
brelse(bp);
|
|
/*
|
|
* If creating, and at end of pathname and current
|
|
* directory has not been removed, then can consider
|
|
* allowing file to be created.
|
|
*/
|
|
if ((nameiop == CREATE || nameiop == RENAME) &&
|
|
(flags & ISLASTCN) && dp->i_nlink != 0) {
|
|
/*
|
|
* Access for write is interpreted as allowing
|
|
* creation of files in the directory.
|
|
*/
|
|
if (error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc))
|
|
return (error);
|
|
/*
|
|
* Return an indication of where the new directory
|
|
* entry should be put. If we didn't find a slot,
|
|
* then set dp->i_count to 0 indicating
|
|
* that the new slot belongs at the end of the
|
|
* directory. If we found a slot, then the new entry
|
|
* can be put in the range from dp->i_offset to
|
|
* dp->i_offset + dp->i_count.
|
|
*/
|
|
if (slotstatus == NONE) {
|
|
dp->i_offset = roundup(dp->i_size, DIRBLKSIZ);
|
|
dp->i_count = 0;
|
|
enduseful = dp->i_offset;
|
|
} else {
|
|
dp->i_offset = slotoffset;
|
|
dp->i_count = slotsize;
|
|
if (enduseful < slotoffset + slotsize)
|
|
enduseful = slotoffset + slotsize;
|
|
}
|
|
dp->i_endoff = roundup(enduseful, DIRBLKSIZ);
|
|
dp->i_flag |= IN_CHANGE | IN_UPDATE;
|
|
/*
|
|
* We return with the directory locked, so that
|
|
* the parameters we set up above will still be
|
|
* valid if we actually decide to do a direnter().
|
|
* We return ni_vp == NULL to indicate that the entry
|
|
* does not currently exist; we leave a pointer to
|
|
* the (locked) directory inode in ndp->ni_dvp.
|
|
* The pathname buffer is saved so that the name
|
|
* can be obtained later.
|
|
*
|
|
* NB - if the directory is unlocked, then this
|
|
* information cannot be used.
|
|
*/
|
|
cnp->cn_flags |= SAVENAME;
|
|
if (!lockparent)
|
|
VOP_UNLOCK(vdp, 0, p);
|
|
return (EJUSTRETURN);
|
|
}
|
|
/*
|
|
* Insert name into cache (as non-existent) if appropriate.
|
|
*/
|
|
if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
|
|
cache_enter(vdp, *vpp, cnp);
|
|
return (ENOENT);
|
|
|
|
found:
|
|
if (numdirpasses == 2)
|
|
nchstats.ncs_pass2++;
|
|
/*
|
|
* Check that directory length properly reflects presence
|
|
* of this entry.
|
|
*/
|
|
if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->name_len)
|
|
> dp->i_size) {
|
|
ufs_dirbad(dp, dp->i_offset, "i_size too small");
|
|
dp->i_size = entryoffsetinblock+EXT2_DIR_REC_LEN(ep->name_len);
|
|
dp->i_flag |= IN_CHANGE | IN_UPDATE;
|
|
}
|
|
|
|
/*
|
|
* Found component in pathname.
|
|
* If the final component of path name, save information
|
|
* in the cache as to where the entry was found.
|
|
*/
|
|
if ((flags & ISLASTCN) && nameiop == LOOKUP)
|
|
dp->i_diroff = dp->i_offset &~ (DIRBLKSIZ - 1);
|
|
|
|
/*
|
|
* If deleting, and at end of pathname, return
|
|
* parameters which can be used to remove file.
|
|
* If the wantparent flag isn't set, we return only
|
|
* the directory (in ndp->ni_dvp), otherwise we go
|
|
* on and lock the inode, being careful with ".".
|
|
*/
|
|
if (nameiop == DELETE && (flags & ISLASTCN)) {
|
|
/*
|
|
* Write access to directory required to delete files.
|
|
*/
|
|
if (error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc))
|
|
return (error);
|
|
/*
|
|
* Return pointer to current entry in dp->i_offset,
|
|
* and distance past previous entry (if there
|
|
* is a previous entry in this block) in dp->i_count.
|
|
* Save directory inode pointer in ndp->ni_dvp for dirremove().
|
|
*/
|
|
if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
|
|
dp->i_count = 0;
|
|
else
|
|
dp->i_count = dp->i_offset - prevoff;
|
|
if (dp->i_number == dp->i_ino) {
|
|
VREF(vdp);
|
|
*vpp = vdp;
|
|
return (0);
|
|
}
|
|
if (error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp))
|
|
return (error);
|
|
/*
|
|
* If directory is "sticky", then user must own
|
|
* the directory, or the file in it, else she
|
|
* may not delete it (unless she's root). This
|
|
* implements append-only directories.
|
|
*/
|
|
if ((dp->i_mode & ISVTX) &&
|
|
cred->cr_uid != 0 &&
|
|
cred->cr_uid != dp->i_uid &&
|
|
VTOI(tdp)->i_uid != cred->cr_uid) {
|
|
vput(tdp);
|
|
return (EPERM);
|
|
}
|
|
*vpp = tdp;
|
|
if (!lockparent)
|
|
VOP_UNLOCK(vdp, 0, p);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* If rewriting (RENAME), return the inode and the
|
|
* information required to rewrite the present directory
|
|
* Must get inode of directory entry to verify it's a
|
|
* regular file, or empty directory.
|
|
*/
|
|
if (nameiop == RENAME && wantparent &&
|
|
(flags & ISLASTCN)) {
|
|
if (error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc))
|
|
return (error);
|
|
/*
|
|
* Careful about locking second inode.
|
|
* This can only occur if the target is ".".
|
|
*/
|
|
if (dp->i_number == dp->i_ino)
|
|
return (EISDIR);
|
|
if (error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp))
|
|
return (error);
|
|
*vpp = tdp;
|
|
cnp->cn_flags |= SAVENAME;
|
|
if (!lockparent)
|
|
VOP_UNLOCK(vdp, 0, p);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Step through the translation in the name. We do not `vput' the
|
|
* directory because we may need it again if a symbolic link
|
|
* is relative to the current directory. Instead we save it
|
|
* unlocked as "pdp". We must get the target inode before unlocking
|
|
* the directory to insure that the inode will not be removed
|
|
* before we get it. We prevent deadlock by always fetching
|
|
* inodes from the root, moving down the directory tree. Thus
|
|
* when following backward pointers ".." we must unlock the
|
|
* parent directory before getting the requested directory.
|
|
* There is a potential race condition here if both the current
|
|
* and parent directories are removed before the VFS_VGET for the
|
|
* inode associated with ".." returns. We hope that this occurs
|
|
* infrequently since we cannot avoid this race condition without
|
|
* implementing a sophisticated deadlock detection algorithm.
|
|
* Note also that this simple deadlock detection scheme will not
|
|
* work if the file system has any hard links other than ".."
|
|
* that point backwards in the directory structure.
|
|
*/
|
|
pdp = vdp;
|
|
if (flags & ISDOTDOT) {
|
|
VOP_UNLOCK(pdp, 0, p); /* race to get the inode */
|
|
if (error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp)) {
|
|
vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p);
|
|
return (error);
|
|
}
|
|
if (lockparent && (flags & ISLASTCN) &&
|
|
(error = vn_lock(pdp, LK_EXCLUSIVE, p))) {
|
|
vput(tdp);
|
|
return (error);
|
|
}
|
|
*vpp = tdp;
|
|
} else if (dp->i_number == dp->i_ino) {
|
|
VREF(vdp); /* we want ourself, ie "." */
|
|
*vpp = vdp;
|
|
} else {
|
|
if (error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp))
|
|
return (error);
|
|
if (!lockparent || !(flags & ISLASTCN))
|
|
VOP_UNLOCK(pdp, 0, p);
|
|
*vpp = tdp;
|
|
}
|
|
|
|
/*
|
|
* Insert name into cache if appropriate.
|
|
*/
|
|
if (cnp->cn_flags & MAKEENTRY)
|
|
cache_enter(vdp, *vpp, cnp);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Do consistency checking on a directory entry:
|
|
* record length must be multiple of 4
|
|
* entry must fit in rest of its DIRBLKSIZ block
|
|
* record must be large enough to contain entry
|
|
* name is not longer than MAXNAMLEN
|
|
* name must be as long as advertised, and null terminated
|
|
*/
|
|
/*
|
|
* changed so that it confirms to ext2_check_dir_entry
|
|
*/
|
|
static int
|
|
ext2_dirbadentry(dp, de, entryoffsetinblock)
|
|
struct vnode *dp;
|
|
register struct ext2_dir_entry *de;
|
|
int entryoffsetinblock;
|
|
{
|
|
int DIRBLKSIZ = VTOI(dp)->i_e2fs->s_blocksize;
|
|
|
|
char * error_msg = NULL;
|
|
|
|
if (de->rec_len < EXT2_DIR_REC_LEN(1))
|
|
error_msg = "rec_len is smaller than minimal";
|
|
else if (de->rec_len % 4 != 0)
|
|
error_msg = "rec_len % 4 != 0";
|
|
else if (de->rec_len < EXT2_DIR_REC_LEN(de->name_len))
|
|
error_msg = "reclen is too small for name_len";
|
|
else if (entryoffsetinblock + de->rec_len > DIRBLKSIZ)
|
|
error_msg = "directory entry across blocks";
|
|
/* else LATER
|
|
if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count)
|
|
error_msg = "inode out of bounds";
|
|
*/
|
|
|
|
if (error_msg != NULL) {
|
|
printf("bad directory entry: %s\n", error_msg);
|
|
printf("offset=%lu, inode=%lu, rec_len=%d, name_len=%d\n",
|
|
entryoffsetinblock, (unsigned long)de->inode,
|
|
de->rec_len, de->name_len);
|
|
}
|
|
return error_msg == NULL ? 0 : 1;
|
|
}
|
|
|
|
/*
|
|
* Write a directory entry after a call to namei, using the parameters
|
|
* that it left in nameidata. The argument ip is the inode which the new
|
|
* directory entry will refer to. Dvp is a pointer to the directory to
|
|
* be written, which was left locked by namei. Remaining parameters
|
|
* (dp->i_offset, dp->i_count) indicate how the space for the new
|
|
* entry is to be obtained.
|
|
*/
|
|
int
|
|
ext2_direnter(ip, dvp, cnp)
|
|
struct inode *ip;
|
|
struct vnode *dvp;
|
|
register struct componentname *cnp;
|
|
{
|
|
register struct ext2_dir_entry *ep, *nep;
|
|
register struct inode *dp;
|
|
struct buf *bp;
|
|
struct ext2_dir_entry newdir;
|
|
struct iovec aiov;
|
|
struct uio auio;
|
|
u_int dsize;
|
|
int error, loc, newentrysize, spacefree;
|
|
char *dirbuf;
|
|
int DIRBLKSIZ = ip->i_e2fs->s_blocksize;
|
|
|
|
|
|
#if DIAGNOSTIC
|
|
if ((cnp->cn_flags & SAVENAME) == 0)
|
|
panic("direnter: missing name");
|
|
#endif
|
|
dp = VTOI(dvp);
|
|
newdir.inode = ip->i_number;
|
|
newdir.name_len = cnp->cn_namelen;
|
|
bcopy(cnp->cn_nameptr, newdir.name, (unsigned)cnp->cn_namelen + 1);
|
|
newentrysize = EXT2_DIR_REC_LEN(newdir.name_len);
|
|
if (dp->i_count == 0) {
|
|
/*
|
|
* If dp->i_count is 0, then namei could find no
|
|
* space in the directory. Here, dp->i_offset will
|
|
* be on a directory block boundary and we will write the
|
|
* new entry into a fresh block.
|
|
*/
|
|
if (dp->i_offset & (DIRBLKSIZ - 1))
|
|
panic("ext2_direnter: newblk");
|
|
auio.uio_offset = dp->i_offset;
|
|
newdir.rec_len = DIRBLKSIZ;
|
|
auio.uio_resid = newentrysize;
|
|
aiov.iov_len = newentrysize;
|
|
aiov.iov_base = (caddr_t)&newdir;
|
|
auio.uio_iov = &aiov;
|
|
auio.uio_iovcnt = 1;
|
|
auio.uio_rw = UIO_WRITE;
|
|
auio.uio_segflg = UIO_SYSSPACE;
|
|
auio.uio_procp = (struct proc *)0;
|
|
error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
|
|
if (DIRBLKSIZ >
|
|
VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_bsize)
|
|
/* XXX should grow with balloc() */
|
|
panic("ext2_direnter: frag size");
|
|
else if (!error) {
|
|
dp->i_size = roundup(dp->i_size, DIRBLKSIZ);
|
|
dp->i_flag |= IN_CHANGE;
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* If dp->i_count is non-zero, then namei found space
|
|
* for the new entry in the range dp->i_offset to
|
|
* dp->i_offset + dp->i_count in the directory.
|
|
* To use this space, we may have to compact the entries located
|
|
* there, by copying them together towards the beginning of the
|
|
* block, leaving the free space in one usable chunk at the end.
|
|
*/
|
|
|
|
/*
|
|
* Increase size of directory if entry eats into new space.
|
|
* This should never push the size past a new multiple of
|
|
* DIRBLKSIZE.
|
|
*
|
|
* N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
|
|
*/
|
|
if (dp->i_offset + dp->i_count > dp->i_size)
|
|
dp->i_size = dp->i_offset + dp->i_count;
|
|
/*
|
|
* Get the block containing the space for the new directory entry.
|
|
*/
|
|
if (error = VOP_BLKATOFF(dvp, (off_t)dp->i_offset, &dirbuf, &bp))
|
|
return (error);
|
|
/*
|
|
* Find space for the new entry. In the simple case, the entry at
|
|
* offset base will have the space. If it does not, then namei
|
|
* arranged that compacting the region dp->i_offset to
|
|
* dp->i_offset + dp->i_count would yield the
|
|
* space.
|
|
*/
|
|
ep = (struct ext2_dir_entry *)dirbuf;
|
|
dsize = EXT2_DIR_REC_LEN(ep->name_len);
|
|
spacefree = ep->rec_len - dsize;
|
|
for (loc = ep->rec_len; loc < dp->i_count; ) {
|
|
nep = (struct ext2_dir_entry *)(dirbuf + loc);
|
|
if (ep->inode) {
|
|
/* trim the existing slot */
|
|
ep->rec_len = dsize;
|
|
ep = (struct ext2_dir_entry *)((char *)ep + dsize);
|
|
} else {
|
|
/* overwrite; nothing there; header is ours */
|
|
spacefree += dsize;
|
|
}
|
|
dsize = EXT2_DIR_REC_LEN(nep->name_len);
|
|
spacefree += nep->rec_len - dsize;
|
|
loc += nep->rec_len;
|
|
bcopy((caddr_t)nep, (caddr_t)ep, dsize);
|
|
}
|
|
/*
|
|
* Update the pointer fields in the previous entry (if any),
|
|
* copy in the new entry, and write out the block.
|
|
*/
|
|
if (ep->inode == 0) {
|
|
if (spacefree + dsize < newentrysize)
|
|
panic("ext2_direnter: compact1");
|
|
newdir.rec_len = spacefree + dsize;
|
|
} else {
|
|
if (spacefree < newentrysize)
|
|
panic("ext2_direnter: compact2");
|
|
newdir.rec_len = spacefree;
|
|
ep->rec_len = dsize;
|
|
ep = (struct ext2_dir_entry *)((char *)ep + dsize);
|
|
}
|
|
bcopy((caddr_t)&newdir, (caddr_t)ep, (u_int)newentrysize);
|
|
error = VOP_BWRITE(bp);
|
|
dp->i_flag |= IN_CHANGE | IN_UPDATE;
|
|
if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
|
|
error = VOP_TRUNCATE(dvp, (off_t)dp->i_endoff, IO_SYNC,
|
|
cnp->cn_cred, cnp->cn_proc);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Remove a directory entry after a call to namei, using
|
|
* the parameters which it left in nameidata. The entry
|
|
* dp->i_offset contains the offset into the directory of the
|
|
* entry to be eliminated. The dp->i_count field contains the
|
|
* size of the previous record in the directory. If this
|
|
* is 0, the first entry is being deleted, so we need only
|
|
* zero the inode number to mark the entry as free. If the
|
|
* entry is not the first in the directory, we must reclaim
|
|
* the space of the now empty record by adding the record size
|
|
* to the size of the previous entry.
|
|
*/
|
|
int
|
|
ext2_dirremove(dvp, cnp)
|
|
struct vnode *dvp;
|
|
struct componentname *cnp;
|
|
{
|
|
register struct inode *dp;
|
|
struct ext2_dir_entry *ep;
|
|
struct buf *bp;
|
|
int error;
|
|
|
|
dp = VTOI(dvp);
|
|
if (dp->i_count == 0) {
|
|
/*
|
|
* First entry in block: set d_ino to zero.
|
|
*/
|
|
if (error =
|
|
VOP_BLKATOFF(dvp, (off_t)dp->i_offset, (char **)&ep, &bp))
|
|
return (error);
|
|
ep->inode = 0;
|
|
error = VOP_BWRITE(bp);
|
|
dp->i_flag |= IN_CHANGE | IN_UPDATE;
|
|
return (error);
|
|
}
|
|
/*
|
|
* Collapse new free space into previous entry.
|
|
*/
|
|
if (error = VOP_BLKATOFF(dvp, (off_t)(dp->i_offset - dp->i_count),
|
|
(char **)&ep, &bp))
|
|
return (error);
|
|
ep->rec_len += dp->i_reclen;
|
|
error = VOP_BWRITE(bp);
|
|
dp->i_flag |= IN_CHANGE | IN_UPDATE;
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Rewrite an existing directory entry to point at the inode
|
|
* supplied. The parameters describing the directory entry are
|
|
* set up by a call to namei.
|
|
*/
|
|
int
|
|
ext2_dirrewrite(dp, ip, cnp)
|
|
struct inode *dp, *ip;
|
|
struct componentname *cnp;
|
|
{
|
|
struct buf *bp;
|
|
struct ext2_dir_entry *ep;
|
|
struct vnode *vdp = ITOV(dp);
|
|
int error;
|
|
|
|
if (error = VOP_BLKATOFF(vdp, (off_t)dp->i_offset, (char **)&ep, &bp))
|
|
return (error);
|
|
ep->inode = ip->i_number;
|
|
error = VOP_BWRITE(bp);
|
|
dp->i_flag |= IN_CHANGE | IN_UPDATE;
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Check if a directory is empty or not.
|
|
* Inode supplied must be locked.
|
|
*
|
|
* Using a struct dirtemplate here is not precisely
|
|
* what we want, but better than using a struct direct.
|
|
*
|
|
* NB: does not handle corrupted directories.
|
|
*/
|
|
int
|
|
ext2_dirempty(ip, parentino, cred)
|
|
register struct inode *ip;
|
|
ino_t parentino;
|
|
struct ucred *cred;
|
|
{
|
|
register off_t off;
|
|
struct dirtemplate dbuf;
|
|
register struct ext2_dir_entry *dp = (struct ext2_dir_entry *)&dbuf;
|
|
int error, count, namlen;
|
|
|
|
#define MINDIRSIZ (sizeof (struct dirtemplate) / 2)
|
|
|
|
for (off = 0; off < ip->i_size; off += dp->rec_len) {
|
|
error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, off,
|
|
UIO_SYSSPACE, IO_NODELOCKED, cred, &count, (struct proc *)0);
|
|
/*
|
|
* Since we read MINDIRSIZ, residual must
|
|
* be 0 unless we're at end of file.
|
|
*/
|
|
if (error || count != 0)
|
|
return (0);
|
|
/* avoid infinite loops */
|
|
if (dp->rec_len == 0)
|
|
return (0);
|
|
/* skip empty entries */
|
|
if (dp->inode == 0)
|
|
continue;
|
|
/* accept only "." and ".." */
|
|
namlen = dp->name_len;
|
|
if (namlen > 2)
|
|
return (0);
|
|
if (dp->name[0] != '.')
|
|
return (0);
|
|
/*
|
|
* At this point namlen must be 1 or 2.
|
|
* 1 implies ".", 2 implies ".." if second
|
|
* char is also "."
|
|
*/
|
|
if (namlen == 1)
|
|
continue;
|
|
if (dp->name[1] == '.' && dp->inode == parentino)
|
|
continue;
|
|
return (0);
|
|
}
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* Check if source directory is in the path of the target directory.
|
|
* Target is supplied locked, source is unlocked.
|
|
* The target is always vput before returning.
|
|
*/
|
|
int
|
|
ext2_checkpath(source, target, cred)
|
|
struct inode *source, *target;
|
|
struct ucred *cred;
|
|
{
|
|
struct vnode *vp;
|
|
int error, rootino, namlen;
|
|
struct dirtemplate dirbuf;
|
|
|
|
vp = ITOV(target);
|
|
if (target->i_number == source->i_number) {
|
|
error = EEXIST;
|
|
goto out;
|
|
}
|
|
rootino = ROOTINO;
|
|
error = 0;
|
|
if (target->i_number == rootino)
|
|
goto out;
|
|
|
|
for (;;) {
|
|
if (vp->v_type != VDIR) {
|
|
error = ENOTDIR;
|
|
break;
|
|
}
|
|
error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
|
|
sizeof (struct dirtemplate), (off_t)0, UIO_SYSSPACE,
|
|
IO_NODELOCKED, cred, (int *)0, (struct proc *)0);
|
|
if (error != 0)
|
|
break;
|
|
namlen = ((struct odirtemplate *)&dirbuf)->dotdot_namlen; /* XXX */
|
|
if (namlen != 2 ||
|
|
dirbuf.dotdot_name[0] != '.' ||
|
|
dirbuf.dotdot_name[1] != '.') {
|
|
error = ENOTDIR;
|
|
break;
|
|
}
|
|
if (dirbuf.dotdot_ino == source->i_number) {
|
|
error = EINVAL;
|
|
break;
|
|
}
|
|
if (dirbuf.dotdot_ino == rootino)
|
|
break;
|
|
vput(vp);
|
|
if (error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino, &vp)) {
|
|
vp = NULL;
|
|
break;
|
|
}
|
|
}
|
|
|
|
out:
|
|
if (error == ENOTDIR)
|
|
printf("checkpath: .. not a directory\n");
|
|
if (vp != NULL)
|
|
vput(vp);
|
|
return (error);
|
|
}
|
|
|