/* $OpenBSD: msdosfs_denode.c,v 1.7 2021/10/06 00:40:41 deraadt Exp $ */ /* $NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $ */ /*- * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. * Copyright (C) 1994, 1995, 1997 TooLs GmbH. * All rights reserved. * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by TooLs GmbH. * 4. The name of TooLs GmbH may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * Written by Paul Popelka (paulp@uts.amdahl.com) * * You can do anything you want with this software, just don't say you wrote * it, and don't remove this notice. * * This software is provided "as is". * * The author supplies this software to be publicly redistributed on the * understanding that the author is not responsible for the correct * functioning of this software in any circumstances and is not liable for * any damages caused by this software. * * October 1992 */ #include "ffs/buf.h" #include <msdosfs/bpb.h> #include "msdos/msdosfsmount.h" #include "msdos/direntry.h" #include "msdos/denode.h" #include "msdos/fat.h" #include <util.h> #include "makefs.h" /* * If deget() succeeds it returns with the gotten denode locked(). * * pmp - address of msdosfsmount structure of the filesystem containing * the denode of interest. The pm_dev field and the address of * the msdosfsmount structure are used. * dirclust - which cluster bp contains, if dirclust is 0 (root directory) * diroffset is relative to the beginning of the root directory, * otherwise it is cluster relative. * diroffset - offset past begin of cluster of denode we want * depp - returns the address of the gotten denode. */ int deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, struct denode **depp) /* pmp: so we know the maj/min number */ /* dirclust: cluster this dir entry came from */ /* diroffset: index of entry within the cluster */ /* depp: returns the addr of the gotten denode */ { int error; struct direntry *direntptr; struct denode *ldep; struct mkfsbuf *bp; #ifdef MSDOSFS_DEBUG printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n", pmp, dirclust, diroffset, depp); #endif /* * On FAT32 filesystems, root is a (more or less) normal * directory */ if (FAT32(pmp) && dirclust == MSDOSFSROOT) dirclust = pmp->pm_rootdirblk; ldep = ecalloc(1, sizeof(*ldep)); ldep->de_mkfsvnode = NULL; ldep->de_flag = 0; ldep->de_devvp = 0; ldep->de_lockf = 0; ldep->de_dev = pmp->pm_dev; ldep->de_dirclust = dirclust; ldep->de_diroffset = diroffset; ldep->de_pmp = pmp; ldep->de_devvp = pmp->pm_devvp; ldep->de_refcnt = 1; fc_purge(ldep, 0); /* * Copy the directory entry into the denode area of the mkfsvnode. */ if ((dirclust == MSDOSFSROOT || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)) && diroffset == MSDOSFSROOT_OFS) { /* * Directory entry for the root directory. There isn't one, * so we manufacture one. We should probably rummage * through the root directory and find a label entry (if it * exists), and then use the time and date from that entry * as the time and date for the root denode. */ ldep->de_mkfsvnode = (struct mkfsvnode *)-1; ldep->de_Attributes = ATTR_DIRECTORY; if (FAT32(pmp)) ldep->de_StartCluster = pmp->pm_rootdirblk; /* de_FileSize will be filled in further down */ else { ldep->de_StartCluster = MSDOSFSROOT; ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec; } /* * fill in time and date so that dos2unixtime() doesn't * spit up when called from msdosfs_getattr() with root * denode */ ldep->de_CHun = 0; ldep->de_CTime = 0x0000; /* 00:00:00 */ ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT) | (1 << DD_DAY_SHIFT); /* Jan 1, 1980 */ ldep->de_ADate = ldep->de_CDate; ldep->de_MTime = ldep->de_CTime; ldep->de_MDate = ldep->de_CDate; /* leave the other fields as garbage */ } else { error = readep(pmp, dirclust, diroffset, &bp, &direntptr); if (error) { ldep->de_devvp = NULL; ldep->de_Name[0] = SLOT_DELETED; return (error); } DE_INTERNALIZE(ldep, direntptr); brelse(bp, 0); } /* * Fill in a few fields of the mkfsvnode and finish filling in the * denode. Then return the address of the found denode. */ if (ldep->de_Attributes & ATTR_DIRECTORY) { /* * Since DOS directory entries that describe directories * have 0 in the filesize field, we take this opportunity * to find out the length of the directory and plug it into * the denode structure. */ u_long size; if (ldep->de_StartCluster != MSDOSFSROOT) { error = pcbmap(ldep, CLUST_END, 0, &size, 0); if (error == E2BIG) { ldep->de_FileSize = de_cn2off(pmp, size); error = 0; } else printf("deget(): pcbmap returned %d\n", error); } } *depp = ldep; return (0); } /* * Truncate the file described by dep to the length specified by length. */ int detrunc(struct denode *dep, u_long length, int flags) { int error; int allerror = 0; u_long eofentry; u_long chaintofree = 0; daddr_t bn, lastblock; int boff; int isadir = dep->de_Attributes & ATTR_DIRECTORY; struct mkfsbuf *bp; struct msdosfsmount *pmp = dep->de_pmp; #ifdef MSDOSFS_DEBUG printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags); #endif /* * Disallow attempts to truncate the root directory since it is of * fixed size. That's just the way dos filesystems are. We use * the VROOT bit in the mkfsvnode because checking for the directory * bit and a startcluster of 0 in the denode is not adequate to * recognize the root directory at this point in a file or * directory's life. */ if (dep->de_mkfsvnode != NULL && !FAT32(pmp)) { printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n", dep->de_dirclust, dep->de_diroffset); return (EINVAL); } if (dep->de_FileSize < length) return (deextend(dep, length)); lastblock = de_clcount(pmp, length) - 1; /* * If the desired length is 0 then remember the starting cluster of * the file and set the StartCluster field in the directory entry * to 0. If the desired length is not zero, then get the number of * the last cluster in the shortened file. Then get the number of * the first cluster in the part of the file that is to be freed. * Then set the next cluster pointer in the last cluster of the * file to CLUST_EOFE. */ if (length == 0) { chaintofree = dep->de_StartCluster; dep->de_StartCluster = 0; eofentry = ~0; } else { error = pcbmap(dep, lastblock, 0, &eofentry, 0); if (error) { #ifdef MSDOSFS_DEBUG printf("detrunc(): pcbmap fails %d\n", error); #endif return (error); } } /* * If the new length is not a multiple of the cluster size then we * must zero the tail end of the new last cluster in case it * becomes part of the file again because of a seek. */ if ((boff = length & pmp->pm_crbomask) != 0) { if (isadir) { bn = cntobn(pmp, eofentry); error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), pmp->pm_bpcluster, B_MODIFY, &bp); if (error) { #ifdef MSDOSFS_DEBUG printf("detrunc(): bread fails %d\n", error); #endif return (error); } memset((char *)bp->b_data + boff, 0, pmp->pm_bpcluster - boff); if (flags & IO_SYNC) bwrite(bp); else bdwrite(bp); } } /* * Write out the updated directory entry. Even if the update fails * we free the trailing clusters. */ dep->de_FileSize = length; if (!isadir) dep->de_flag |= DE_UPDATE|DE_MODIFIED; #ifdef MSDOSFS_DEBUG printf("detrunc(): allerror %d, eofentry %lu\n", allerror, eofentry); #endif /* * If we need to break the cluster chain for the file then do it * now. */ if (eofentry != (u_long)~0) { error = fatentry(FAT_GET_AND_SET, pmp, eofentry, &chaintofree, CLUST_EOFE); if (error) { #ifdef MSDOSFS_DEBUG printf("detrunc(): fatentry errors %d\n", error); #endif return (error); } } /* * Now free the clusters removed from the file because of the * truncation. */ if (chaintofree != 0 && !MSDOSFSEOF(chaintofree, pmp->pm_fatmask)) freeclusterchain(pmp, chaintofree); return (allerror); } /* * Extend the file described by dep to length specified by length. */ int deextend(struct denode *dep, u_long length) { struct msdosfsmount *pmp = dep->de_pmp; u_long count; int error; /* * The root of a DOS filesystem cannot be extended. */ if (dep->de_mkfsvnode != NULL && !FAT32(pmp)) return EINVAL; /* * Directories cannot be extended. */ if (dep->de_Attributes & ATTR_DIRECTORY) return EISDIR; if (length <= dep->de_FileSize) return E2BIG; /* * Compute the number of clusters to allocate. */ count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize); if (count > 0) { if (count > pmp->pm_freeclustercount) return (ENOSPC); error = extendfile(dep, count, NULL, NULL, DE_CLEAR); if (error) { /* truncate the added clusters away again */ (void) detrunc(dep, dep->de_FileSize, 0); return (error); } } /* * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a * memset(); we set the write size so ubc won't read in file data that * is zero'd later. */ dep->de_FileSize = length; dep->de_flag |= DE_UPDATE|DE_MODIFIED; return 0; }
