364 lines
11 KiB
C
364 lines
11 KiB
C
/* $NetBSD: msdosfs_denode.c,v 1.6 2013/10/19 17:16:37 christos Exp $ */
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/*-
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* Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
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* Copyright (C) 1994, 1995, 1997 TooLs GmbH.
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* All rights reserved.
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* Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
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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 TooLs GmbH.
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* 4. The name of TooLs GmbH may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Written by Paul Popelka (paulp@uts.amdahl.com)
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*
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* You can do anything you want with this software, just don't say you wrote
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* it, and don't remove this notice.
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*
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* This software is provided "as is".
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*
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* The author supplies this software to be publicly redistributed on the
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* understanding that the author is not responsible for the correct
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* functioning of this software in any circumstances and is not liable for
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* any damages caused by this software.
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*
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* October 1992
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*/
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#if HAVE_NBTOOL_CONFIG_H
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#include "nbtool_config.h"
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#endif
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: msdosfs_denode.c,v 1.6 2013/10/19 17:16:37 christos Exp $");
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#include <sys/param.h>
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#include <ffs/buf.h>
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#include <fs/msdosfs/bpb.h>
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#include <fs/msdosfs/msdosfsmount.h>
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#include <fs/msdosfs/direntry.h>
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#include <fs/msdosfs/denode.h>
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#include <fs/msdosfs/fat.h>
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#include <util.h>
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/*
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* If deget() succeeds it returns with the gotten denode locked().
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*
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* pmp - address of msdosfsmount structure of the filesystem containing
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* the denode of interest. The pm_dev field and the address of
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* the msdosfsmount structure are used.
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* dirclust - which cluster bp contains, if dirclust is 0 (root directory)
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* diroffset is relative to the beginning of the root directory,
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* otherwise it is cluster relative.
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* diroffset - offset past begin of cluster of denode we want
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* depp - returns the address of the gotten denode.
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*/
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int
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deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
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struct denode **depp)
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/* pmp: so we know the maj/min number */
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/* dirclust: cluster this dir entry came from */
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/* diroffset: index of entry within the cluster */
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/* depp: returns the addr of the gotten denode */
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{
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int error;
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struct direntry *direntptr;
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struct denode *ldep;
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struct buf *bp;
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#ifdef MSDOSFS_DEBUG
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printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n",
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pmp, dirclust, diroffset, depp);
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#endif
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/*
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* On FAT32 filesystems, root is a (more or less) normal
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* directory
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*/
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if (FAT32(pmp) && dirclust == MSDOSFSROOT)
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dirclust = pmp->pm_rootdirblk;
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ldep = ecalloc(1, sizeof(*ldep));
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ldep->de_vnode = NULL;
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ldep->de_flag = 0;
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ldep->de_devvp = 0;
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ldep->de_lockf = 0;
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ldep->de_dev = pmp->pm_dev;
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ldep->de_dirclust = dirclust;
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ldep->de_diroffset = diroffset;
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ldep->de_pmp = pmp;
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ldep->de_devvp = pmp->pm_devvp;
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ldep->de_refcnt = 1;
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fc_purge(ldep, 0);
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/*
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* Copy the directory entry into the denode area of the vnode.
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*/
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if ((dirclust == MSDOSFSROOT
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|| (FAT32(pmp) && dirclust == pmp->pm_rootdirblk))
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&& diroffset == MSDOSFSROOT_OFS) {
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/*
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* Directory entry for the root directory. There isn't one,
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* so we manufacture one. We should probably rummage
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* through the root directory and find a label entry (if it
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* exists), and then use the time and date from that entry
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* as the time and date for the root denode.
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*/
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ldep->de_vnode = (struct vnode *)-1;
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ldep->de_Attributes = ATTR_DIRECTORY;
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if (FAT32(pmp))
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ldep->de_StartCluster = pmp->pm_rootdirblk;
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/* de_FileSize will be filled in further down */
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else {
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ldep->de_StartCluster = MSDOSFSROOT;
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ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec;
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}
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/*
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* fill in time and date so that dos2unixtime() doesn't
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* spit up when called from msdosfs_getattr() with root
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* denode
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*/
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ldep->de_CHun = 0;
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ldep->de_CTime = 0x0000; /* 00:00:00 */
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ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT)
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| (1 << DD_DAY_SHIFT);
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/* Jan 1, 1980 */
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ldep->de_ADate = ldep->de_CDate;
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ldep->de_MTime = ldep->de_CTime;
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ldep->de_MDate = ldep->de_CDate;
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/* leave the other fields as garbage */
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} else {
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error = readep(pmp, dirclust, diroffset, &bp, &direntptr);
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if (error) {
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ldep->de_devvp = NULL;
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ldep->de_Name[0] = SLOT_DELETED;
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return (error);
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}
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DE_INTERNALIZE(ldep, direntptr);
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brelse(bp, 0);
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}
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/*
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* Fill in a few fields of the vnode and finish filling in the
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* denode. Then return the address of the found denode.
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*/
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if (ldep->de_Attributes & ATTR_DIRECTORY) {
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/*
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* Since DOS directory entries that describe directories
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* have 0 in the filesize field, we take this opportunity
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* to find out the length of the directory and plug it into
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* the denode structure.
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*/
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u_long size;
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if (ldep->de_StartCluster != MSDOSFSROOT) {
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error = pcbmap(ldep, CLUST_END, 0, &size, 0);
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if (error == E2BIG) {
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ldep->de_FileSize = de_cn2off(pmp, size);
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error = 0;
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} else
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printf("deget(): pcbmap returned %d\n", error);
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}
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}
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*depp = ldep;
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return (0);
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}
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/*
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* Truncate the file described by dep to the length specified by length.
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*/
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int
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detrunc(struct denode *dep, u_long length, int flags, struct kauth_cred *cred)
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{
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int error;
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int allerror = 0;
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u_long eofentry;
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u_long chaintofree = 0;
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daddr_t bn, lastblock;
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int boff;
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int isadir = dep->de_Attributes & ATTR_DIRECTORY;
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struct buf *bp;
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struct msdosfsmount *pmp = dep->de_pmp;
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#ifdef MSDOSFS_DEBUG
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printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags);
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#endif
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/*
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* Disallow attempts to truncate the root directory since it is of
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* fixed size. That's just the way dos filesystems are. We use
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* the VROOT bit in the vnode because checking for the directory
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* bit and a startcluster of 0 in the denode is not adequate to
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* recognize the root directory at this point in a file or
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* directory's life.
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*/
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if (dep->de_vnode != NULL && !FAT32(pmp)) {
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printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n",
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dep->de_dirclust, dep->de_diroffset);
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return (EINVAL);
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}
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if (dep->de_FileSize < length)
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return (deextend(dep, length, cred));
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lastblock = de_clcount(pmp, length) - 1;
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/*
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* If the desired length is 0 then remember the starting cluster of
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* the file and set the StartCluster field in the directory entry
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* to 0. If the desired length is not zero, then get the number of
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* the last cluster in the shortened file. Then get the number of
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* the first cluster in the part of the file that is to be freed.
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* Then set the next cluster pointer in the last cluster of the
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* file to CLUST_EOFE.
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*/
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if (length == 0) {
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chaintofree = dep->de_StartCluster;
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dep->de_StartCluster = 0;
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eofentry = ~0;
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} else {
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error = pcbmap(dep, lastblock, 0, &eofentry, 0);
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if (error) {
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#ifdef MSDOSFS_DEBUG
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printf("detrunc(): pcbmap fails %d\n", error);
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#endif
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return (error);
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}
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}
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/*
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* If the new length is not a multiple of the cluster size then we
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* must zero the tail end of the new last cluster in case it
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* becomes part of the file again because of a seek.
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*/
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if ((boff = length & pmp->pm_crbomask) != 0) {
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if (isadir) {
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bn = cntobn(pmp, eofentry);
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error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
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pmp->pm_bpcluster, NOCRED, B_MODIFY, &bp);
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if (error) {
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#ifdef MSDOSFS_DEBUG
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printf("detrunc(): bread fails %d\n", error);
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#endif
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return (error);
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}
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memset((char *)bp->b_data + boff, 0,
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pmp->pm_bpcluster - boff);
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if (flags & IO_SYNC)
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bwrite(bp);
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else
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bdwrite(bp);
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}
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}
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/*
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* Write out the updated directory entry. Even if the update fails
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* we free the trailing clusters.
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*/
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dep->de_FileSize = length;
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if (!isadir)
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dep->de_flag |= DE_UPDATE|DE_MODIFIED;
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#ifdef MSDOSFS_DEBUG
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printf("detrunc(): allerror %d, eofentry %lu\n",
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allerror, eofentry);
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#endif
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/*
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* If we need to break the cluster chain for the file then do it
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* now.
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*/
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if (eofentry != (u_long)~0) {
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error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
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&chaintofree, CLUST_EOFE);
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if (error) {
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#ifdef MSDOSFS_DEBUG
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printf("detrunc(): fatentry errors %d\n", error);
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#endif
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return (error);
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}
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}
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/*
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* Now free the clusters removed from the file because of the
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* truncation.
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*/
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if (chaintofree != 0 && !MSDOSFSEOF(chaintofree, pmp->pm_fatmask))
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freeclusterchain(pmp, chaintofree);
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return (allerror);
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}
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/*
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* Extend the file described by dep to length specified by length.
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*/
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int
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deextend(struct denode *dep, u_long length, struct kauth_cred *cred)
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{
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struct msdosfsmount *pmp = dep->de_pmp;
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u_long count;
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int error;
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/*
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* The root of a DOS filesystem cannot be extended.
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*/
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if (dep->de_vnode != NULL && !FAT32(pmp))
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return EINVAL;
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/*
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* Directories cannot be extended.
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*/
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if (dep->de_Attributes & ATTR_DIRECTORY)
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return EISDIR;
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if (length <= dep->de_FileSize)
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return E2BIG;
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/*
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* Compute the number of clusters to allocate.
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*/
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count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize);
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if (count > 0) {
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if (count > pmp->pm_freeclustercount)
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return (ENOSPC);
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error = extendfile(dep, count, NULL, NULL, DE_CLEAR);
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if (error) {
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/* truncate the added clusters away again */
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(void) detrunc(dep, dep->de_FileSize, 0, cred);
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return (error);
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}
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}
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/*
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* Zero extend file range; ubc_zerorange() uses ubc_alloc() and a
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* memset(); we set the write size so ubc won't read in file data that
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* is zero'd later.
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*/
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dep->de_FileSize = length;
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dep->de_flag |= DE_UPDATE|DE_MODIFIED;
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return 0;
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}
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