xref: /freebsd/usr.sbin/makefs/msdos/msdosfs_lookup.c (revision 2a63c3be158216222d89a073dcbd6a72ee4aab5a)

/*	$NetBSD: msdosfs_lookup.c,v 1.37 1997/11/17 15:36:54 ws Exp $	*/

/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * 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 <sys/param.h>
#include <sys/errno.h>

#include <stdbool.h>
#include <stdio.h>
#include <string.h>

#include <fs/msdosfs/bpb.h>
#include "msdos/denode.h"
#include <fs/msdosfs/fat.h>
#include <fs/msdosfs/msdosfsmount.h>

#include "makefs.h"
#include "msdos.h"

/*
 * dep  - directory entry to copy into the directory
 * ddep - directory to add to
 * depp - return the address of the denode for the created directory entry
 *	  if depp != 0
 * cnp  - componentname needed for Win95 long filenames
 */
int
createde(struct denode *dep, struct denode *ddep, struct denode **depp,
    struct componentname *cnp)
{
	int error;
	u_long dirclust, diroffset;
	struct direntry *ndep;
	struct msdosfsmount *pmp = ddep->de_pmp;
	struct m_buf *bp;
	daddr_t bn;
	int blsize;

	MSDOSFS_DPRINTF(("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
	    dep, ddep, depp, cnp));

	/*
	 * If no space left in the directory then allocate another cluster
	 * and chain it onto the end of the file.  There is one exception
	 * to this.  That is, if the root directory has no more space it
	 * can NOT be expanded.  extendfile() checks for and fails attempts
	 * to extend the root directory.  We just return an error in that
	 * case.
	 */
	if (ddep->de_fndoffset >= ddep->de_FileSize) {
		diroffset = ddep->de_fndoffset + sizeof(struct direntry)
		    - ddep->de_FileSize;
		dirclust = de_clcount(pmp, diroffset);
		error = m_extendfile(ddep, dirclust, 0, 0, DE_CLEAR);
		if (error) {
			(void)detrunc(ddep, ddep->de_FileSize, 0, NULL);
			return error;
		}

		/*
		 * Update the size of the directory
		 */
		ddep->de_FileSize += de_cn2off(pmp, dirclust);
	}

	/*
	 * We just read in the cluster with space.  Copy the new directory
	 * entry in.  Then write it to disk. NOTE:  DOS directories
	 * do not get smaller as clusters are emptied.
	 */
	error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset),
		       &bn, &dirclust, &blsize);
	if (error)
		return error;
	diroffset = ddep->de_fndoffset;
	if (dirclust != MSDOSFSROOT)
		diroffset &= pmp->pm_crbomask;
	if ((error = bread((void *)pmp->pm_devvp, bn, blsize, NOCRED,
	    &bp)) != 0) {
		return error;
	}
	ndep = bptoep(pmp, bp, ddep->de_fndoffset);

	DE_EXTERNALIZE(ndep, dep);

	/*
	 * Now write the Win95 long name
	 */
	if (ddep->de_fndcnt > 0) {
		uint8_t chksum = winChksum(ndep->deName);
		const u_char *un = (const u_char *)cnp->cn_nameptr;
		int unlen = cnp->cn_namelen;
		int cnt = 1;

		while (--ddep->de_fndcnt >= 0) {
			if (!(ddep->de_fndoffset & pmp->pm_crbomask)) {
				if ((error = bwrite(bp)) != 0)
					return error;

				ddep->de_fndoffset -= sizeof(struct direntry);
				error = pcbmap(ddep,
					       de_cluster(pmp,
							  ddep->de_fndoffset),
					       &bn, 0, &blsize);
				if (error)
					return error;

				error = bread((void *)pmp->pm_devvp, bn, blsize,
					      NOCRED, &bp);
				if (error) {
					return error;
				}
				ndep = bptoep(pmp, bp, ddep->de_fndoffset);
			} else {
				ndep--;
				ddep->de_fndoffset -= sizeof(struct direntry);
			}
			if (!unix2winfn(un, unlen, (struct winentry *)ndep,
					cnt++, chksum))
				break;
		}
	}

	if ((error = bwrite(bp)) != 0)
		return error;

	/*
	 * If they want us to return with the denode gotten.
	 */
	if (depp) {
		if (dep->de_Attributes & ATTR_DIRECTORY) {
			dirclust = dep->de_StartCluster;
			if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)
				dirclust = MSDOSFSROOT;
			if (dirclust == MSDOSFSROOT)
				diroffset = MSDOSFSROOT_OFS;
			else
				diroffset = 0;
		}
		return deget(pmp, dirclust, diroffset, 0, depp);
	}

	return 0;
}

/*
 * Read in the disk block containing the directory entry (dirclu, dirofs)
 * and return the address of the buf header, and the address of the
 * directory entry within the block.
 */
int
m_readep(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
    struct m_buf **bpp, struct direntry **epp)
{
	int error;
	daddr_t bn;
	int blsize;

	blsize = pmp->pm_bpcluster;
	if (dirclust == MSDOSFSROOT
	    && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
		blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
	bn = detobn(pmp, dirclust, diroffset);
	if ((error = bread((void *)pmp->pm_devvp, bn, blsize, NOCRED,
	    bpp)) != 0) {
		*bpp = NULL;
		return (error);
	}
	if (epp)
		*epp = bptoep(pmp, *bpp, diroffset);
	return (0);
}

/*
 * Read in the disk block containing the directory entry dep came from and
 * return the address of the buf header, and the address of the directory
 * entry within the block.
 */
int
m_readde(struct denode *dep, struct m_buf **bpp, struct direntry **epp)
{

	return (m_readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
	    bpp, epp));
}

/*
 * Create a unique DOS name in dvp
 */
int
uniqdosname(struct denode *dep, struct componentname *cnp, u_char *cp)
{
	struct msdosfsmount *pmp = dep->de_pmp;
	struct direntry *dentp;
	int gen;
	int blsize;
	u_long cn;
	daddr_t bn;
	struct m_buf *bp;
	int error;

	if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
		return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
		    cnp->cn_namelen, 0) ? 0 : EINVAL);

	for (gen = 1;; gen++) {
		/*
		 * Generate DOS name with generation number
		 */
		if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp,
		    cnp->cn_namelen, gen))
			return gen == 1 ? EINVAL : EEXIST;

		/*
		 * Now look for a dir entry with this exact name
		 */
		for (cn = error = 0; !error; cn++) {
			if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
				if (error == E2BIG)	/* EOF reached and not found */
					return 0;
				return error;
			}
			error = bread((void *)pmp->pm_devvp, bn, blsize,
			    NOCRED, &bp);
			if (error) {
				return error;
			}
			for (dentp = (struct direntry *)bp->b_data;
			     (char *)dentp < bp->b_data + blsize;
			     dentp++) {
				if (dentp->deName[0] == SLOT_EMPTY) {
					/*
					 * Last used entry and not found
					 */
					brelse(bp);
					return 0;
				}
				/*
				 * Ignore volume labels and Win95 entries
				 */
				if (dentp->deAttributes & ATTR_VOLUME)
					continue;
				if (!bcmp(dentp->deName, cp, 11)) {
					error = EEXIST;
					break;
				}
			}
			brelse(bp);
		}
	}
}