Exemple #1
0
/*
 * 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;
	uint32_t cn;
	daddr_t bn;
	struct buf *bp;
	int error;

	for (gen = 1;; gen++) {
		/*
		 * Generate DOS name with generation number
		 */
		if (!unix2dosfn((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(pmp->pm_devvp, bn, blsize, &bp);
			if (error) {
				brelse(bp);
				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);
		}
	}

	return (EEXIST);
}
/*
 * Find any Win'95 long filename entry in directory dep
 */
int
findwin95(struct denode *dep)
{
	struct msdosfsmount *pmp = dep->de_pmp;
	struct direntry *dentp;
	int blsize, win95;
	u_long cn;
	daddr_t bn;
	struct buf *bp;

	win95 = 1;
	/*
	 * Read through the directory looking for Win'95 entries
	 * XXX Note: Error currently handled just as EOF
	 */
	for (cn = 0;; cn++) {
		if (pcbmap(dep, cn, &bn, 0, &blsize))
			return win95;
		if (bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED,
		    0, &bp)) {
			return win95;
		}
		for (dentp = (struct direntry *)bp->b_data;
		     (char *)dentp < (char *)bp->b_data + blsize;
		     dentp++) {
			if (dentp->deName[0] == SLOT_EMPTY) {
				/*
				 * Last used entry and not found
				 */
				brelse(bp, 0);
				return win95;
			}
			if (dentp->deName[0] == SLOT_DELETED) {
				/*
				 * Ignore deleted files
				 * Note: might be an indication of Win'95
				 * anyway	XXX
				 */
				continue;
			}
			if (dentp->deAttributes == ATTR_WIN95) {
				brelse(bp, 0);
				return 1;
			}
			win95 = 0;
		}
		brelse(bp, 0);
	}
}
Exemple #3
0
/*
 * vp  - address of vnode file the file
 * bn  - which cluster we are interested in mapping to a filesystem block number.
 * vpp - returns the vnode for the block special file holding the filesystem
 *	 containing the file of interest
 * bnp - address of where to return the filesystem relative block number
 */
int
msdosfs_bmap(void *v)
{
	struct vop_bmap_args *ap = v;
	struct denode *dep = VTODE(ap->a_vp);
	struct msdosfsmount *pmp = dep->de_pmp;

	if (ap->a_vpp != NULL)
		*ap->a_vpp = dep->de_devvp;
	if (ap->a_bnp == NULL)
		return (0);
	if (ap->a_runp) {
		/*
		 * Sequential clusters should be counted here.
		 */
		*ap->a_runp = 0;
	}
	return (pcbmap(dep, de_bn2cn(pmp, ap->a_bn), ap->a_bnp, 0, 0));
}
Exemple #4
0
int
msdosfs_strategy(void *v)
{
	struct vop_strategy_args *ap = v;
	struct buf *bp = ap->a_bp;
	struct denode *dep = VTODE(bp->b_vp);
	struct vnode *vp;
	int error = 0;
	int s;

	if (bp->b_vp->v_type == VBLK || bp->b_vp->v_type == VCHR)
		panic("msdosfs_strategy: spec");
	/*
	 * If we don't already know the filesystem relative block number
	 * then get it using pcbmap().  If pcbmap() returns the block
	 * number as -1 then we've got a hole in the file.  DOS filesystems
	 * don't allow files with holes, so we shouldn't ever see this.
	 */
	if (bp->b_blkno == bp->b_lblkno) {
		error = pcbmap(dep, de_bn2cn(dep->de_pmp, bp->b_lblkno),
			       &bp->b_blkno, 0, 0);
		if (error)
			bp->b_blkno = -1;
		if (bp->b_blkno == -1)
			clrbuf(bp);
	}
	if (bp->b_blkno == -1) {
		s = splbio();	
		biodone(bp);
		splx(s);
		return (error);
	}

	/*
	 * Read/write the block from/to the disk that contains the desired
	 * file block.
	 */

	vp = dep->de_devvp;
	bp->b_dev = vp->v_rdev;
	(vp->v_op->vop_strategy)(ap);
	return (0);
}
Exemple #5
0
/*
 * Write data to a file or directory.
 */
static int
msdosfs_wfile(const char *path, struct denode *dep, fsnode *node)
{
	int error, fd;
	size_t osize = dep->de_FileSize;
	struct stat *st = &node->inode->st;
	size_t nsize, offs;
	struct msdosfsmount *pmp = dep->de_pmp;
	struct buf *bp;
	char *dat;
	u_long cn = 0;

	error = 0;	/* XXX: gcc/vax */
	DPRINTF(("%s(diroff %lu, dirclust %lu, startcluster %lu)\n", __func__,
	    dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster));
	if (st->st_size == 0)
		return 0;

	/* Don't bother to try to write files larger than the fs limit */
	if (st->st_size > MSDOSFS_FILESIZE_MAX) {
		errno = EFBIG;
		return -1;
	}

	nsize = st->st_size;
	DPRINTF(("%s(nsize=%zu, osize=%zu)\n", __func__, nsize, osize));
	if (nsize > osize) {
		if ((error = deextend(dep, nsize, NULL)) != 0) {
			errno = error;
			return -1;
		}
		if ((error = msdosfs_updatede(dep)) != 0) {
			errno = error;
			return -1;
		}
	}

	if ((fd = open(path, O_RDONLY)) == -1)
		err(1, "open %s", path);

	if ((dat = mmap(0, nsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0))
	    == MAP_FAILED) {
		DPRINTF(("%s: mmap %s %s", __func__, node->name,
		    strerror(errno)));
		close(fd);
		goto out;
	}
	close(fd);

	for (offs = 0; offs < nsize;) {
		int blsize, cpsize;
		daddr_t bn;
		u_long on = offs & pmp->pm_crbomask;
#ifdef HACK
		cn = dep->de_StartCluster;
		if (cn == MSDOSFSROOT) {
			DPRINTF(("%s: bad lbn %lu", __func__, cn));
			goto out;
		}
		bn = cntobn(pmp, cn);
		blsize = pmp->pm_bpcluster;
#else
		if ((error = pcbmap(dep, cn++, &bn, NULL, &blsize)) != 0) {
			DPRINTF(("%s: pcbmap %lu", __func__, bn));
			goto out;
		}
#endif
		DPRINTF(("%s(cn=%lu, bn=%llu/%llu, blsize=%d)\n", __func__,
		    cn, (unsigned long long)bn,
		    (unsigned long long)de_bn2kb(pmp, bn), blsize));
		if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize,
		    0, &bp)) != 0) {
			DPRINTF(("bread %d\n", error));
			goto out;
		} 
		cpsize = MIN((nsize - offs), blsize - on);
		memcpy((char *)bp->b_data + on, dat + offs, cpsize);
		bwrite(bp);
		offs += cpsize;
	}

	munmap(dat, nsize);
	return 0;
out:
	munmap(dat, nsize);
	return error;
}
Exemple #6
0
/*
 * When we search a directory the blocks containing directory entries are
 * read and examined.  The directory entries contain information that would
 * normally be in the inode of a unix filesystem.  This means that some of
 * a directory's contents may also be in memory resident denodes (sort of
 * an inode).  This can cause problems if we are searching while some other
 * process is modifying a directory.  To prevent one process from accessing
 * incompletely modified directory information we depend upon being the
 * sole owner of a directory block.  bread/brelse provide this service.
 * This being the case, when a process modifies a directory it must first
 * acquire the disk block that contains the directory entry to be modified.
 * Then update the disk block and the denode, and then write the disk block
 * out to disk.	 This way disk blocks containing directory entries and in
 * memory denode's will be in synch.
 */
static int
msdosfs_findslot(struct denode *dp, struct componentname *cnp) 
{
	daddr_t bn;
	int error;
	int slotcount;
	int slotoffset = 0;
	int frcn;
	u_long cluster;
	int blkoff;
	u_int diroff;
	int blsize;
	struct msdosfsmount *pmp;
	struct buf *bp = 0;
	struct direntry *dep;
	u_char dosfilename[12];
	int wincnt = 1;
	int chksum = -1, chksum_ok;
	int olddos = 1;

	pmp = dp->de_pmp;

	switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
	    cnp->cn_namelen, 0)) {
	case 0:
		return (EINVAL);
	case 1:
		break;
	case 2:
		wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
		    cnp->cn_namelen, pmp->pm_flags & MSDOSFSMNT_UTF8) + 1;
		break;
	case 3:
		olddos = 0;
		wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
		    cnp->cn_namelen, pmp->pm_flags & MSDOSFSMNT_UTF8) + 1;
		break;
	}

	if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
		wincnt = 1;

	/*
	 * Suppress search for slots unless creating
	 * file and at end of pathname, in which case
	 * we watch for a place to put the new file in
	 * case it doesn't already exist.
	 */
	slotcount = 0;
	DPRINTF(("%s(): dos filename: %s\n", __func__, dosfilename));
	/*
	 * Search the directory pointed at by vdp for the name pointed at
	 * by cnp->cn_nameptr.
	 */
	/*
	 * The outer loop ranges over the clusters that make up the
	 * directory.  Note that the root directory is different from all
	 * other directories.  It has a fixed number of blocks that are not
	 * part of the pool of allocatable clusters.  So, we treat it a
	 * little differently. The root directory starts at "cluster" 0.
	 */
	diroff = 0;
	for (frcn = 0; diroff < dp->de_FileSize; frcn++) {
		if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) {
			if (error == E2BIG)
				break;
			return (error);
		}
		error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize,
		    0, &bp);
		if (error) {
			return (error);
		}
		for (blkoff = 0; blkoff < blsize;
		     blkoff += sizeof(struct direntry),
		     diroff += sizeof(struct direntry)) {
			dep = (struct direntry *)((char *)bp->b_data + blkoff);
			/*
			 * If the slot is empty and we are still looking
			 * for an empty then remember this one.	 If the
			 * slot is not empty then check to see if it
			 * matches what we are looking for.  If the slot
			 * has never been filled with anything, then the
			 * remainder of the directory has never been used,
			 * so there is no point in searching it.
			 */
			if (dep->deName[0] == SLOT_EMPTY ||
			    dep->deName[0] == SLOT_DELETED) {
				/*
				 * Drop memory of previous long matches
				 */
				chksum = -1;

				if (slotcount < wincnt) {
					slotcount++;
					slotoffset = diroff;
				}
				if (dep->deName[0] == SLOT_EMPTY) {
					brelse(bp, 0);
					goto notfound;
				}
			} else {
				/*
				 * If there wasn't enough space for our
				 * winentries, forget about the empty space
				 */
				if (slotcount < wincnt)
					slotcount = 0;

				/*
				 * Check for Win95 long filename entry
				 */
				if (dep->deAttributes == ATTR_WIN95) {
					if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
						continue;

					chksum = winChkName((const u_char *)cnp->cn_nameptr,
							    cnp->cn_namelen,
							    (struct winentry *)dep,
							    chksum,
							    pmp->pm_flags & MSDOSFSMNT_UTF8);
					continue;
				}

				/*
				 * Ignore volume labels (anywhere, not just
				 * the root directory).
				 */
				if (dep->deAttributes & ATTR_VOLUME) {
					chksum = -1;
					continue;
				}

				/*
				 * Check for a checksum or name match
				 */
				chksum_ok = (chksum == winChksum(dep->deName));
				if (!chksum_ok
				    && (!olddos || memcmp(dosfilename, dep->deName, 11))) {
					chksum = -1;
					continue;
				}
				DPRINTF(("%s(): match blkoff %d, diroff %d\n",
				    __func__, blkoff, diroff));
				/*
				 * Remember where this directory
				 * entry came from for whoever did
				 * this lookup.
				 */
				dp->de_fndoffset = diroff;
				dp->de_fndcnt = 0;

				return EEXIST;
			}
		}	/* for (blkoff = 0; .... */
		/*
		 * Release the buffer holding the directory cluster just
		 * searched.
		 */
		brelse(bp, 0);
	}	/* for (frcn = 0; ; frcn++) */

notfound:
	/*
	 * We hold no disk buffers at this point.
	 */

	/*
	 * If we get here we didn't find the entry we were looking for. But
	 * that's ok if we are creating or renaming and are at the end of
	 * the pathname and the directory hasn't been removed.
	 */
	DPRINTF(("%s(): refcnt %ld, slotcount %d, slotoffset %d\n",
	    __func__, dp->de_refcnt, slotcount, slotoffset));
	/*
	 * Fixup the slot description to point to the place where
	 * we might put the new DOS direntry (putting the Win95
	 * long name entries before that)
	 */
	if (!slotcount) {
		slotcount = 1;
		slotoffset = diroff;
	}
	if (wincnt > slotcount) {
		slotoffset += sizeof(struct direntry) * (wincnt - slotcount);
	}

	/*
	 * Return an indication of where the new directory
	 * entry should be put.
	 */
	dp->de_fndoffset = slotoffset;
	dp->de_fndcnt = wincnt - 1;

	/*
	 * 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.
	 *
	 * NB - if the directory is unlocked, then this
	 * information cannot be used.
	 */
	return 0;
}
Exemple #7
0
/*
 * When we search a directory the blocks containing directory entries are
 * read and examined.  The directory entries contain information that would
 * normally be in the inode of a unix filesystem.  This means that some of
 * a directory's contents may also be in memory resident denodes (sort of
 * an inode).  This can cause problems if we are searching while some other
 * process is modifying a directory.  To prevent one process from accessing
 * incompletely modified directory information we depend upon being the
 * sole owner of a directory block.  bread/brelse provide this service.
 * This being the case, when a process modifies a directory it must first
 * acquire the disk block that contains the directory entry to be modified.
 * Then update the disk block and the denode, and then write the disk block
 * out to disk.  This way disk blocks containing directory entries and in
 * memory denode's will be in synch.
 *
 * msdosfs_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
 *		  struct componentname *a_cnp)
 */
int
msdosfs_lookup(struct vop_old_lookup_args *ap)
{
	struct mbnambuf nb;
	struct vnode *vdp = ap->a_dvp;
	struct vnode **vpp = ap->a_vpp;
	struct componentname *cnp = ap->a_cnp;
	daddr_t bn;
	int error;
	int lockparent;
	int wantparent;
	int slotcount;
	int slotoffset = 0;
	int frcn;
	u_long cluster;
	int blkoff;
	int diroff;
	int blsize;
	int isadir;		/* ~0 if found direntry is a directory	 */
	u_long scn;		/* starting cluster number		 */
	struct vnode *pdp;
	struct denode *dp;
	struct denode *tdp;
	struct msdosfsmount *pmp;
	struct buf *bp = NULL;
	struct direntry *dep = NULL;
	u_char dosfilename[12];
	int flags = cnp->cn_flags;
	int nameiop = cnp->cn_nameiop;
	int unlen;

	int wincnt = 1;
	int chksum = -1;
	int olddos = 1;
	cnp->cn_flags &= ~CNP_PDIRUNLOCK;

#ifdef MSDOSFS_DEBUG
	kprintf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
#endif
	dp = VTODE(vdp);
	pmp = dp->de_pmp;
	*vpp = NULL;
	lockparent = flags & CNP_LOCKPARENT;
	wantparent = flags & (CNP_LOCKPARENT | CNP_WANTPARENT);
#ifdef MSDOSFS_DEBUG
	kprintf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n",
	    vdp, dp, dp->de_Attributes);
#endif

	/*
	 * If they are going after the . or .. entry in the root directory,
	 * they won't find it.  DOS filesystems don't have them in the root
	 * directory.  So, we fake it. deget() is in on this scam too.
	 */
	if ((vdp->v_flag & VROOT) && cnp->cn_nameptr[0] == '.' &&
	    (cnp->cn_namelen == 1 ||
		(cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
		isadir = ATTR_DIRECTORY;
		scn = MSDOSFSROOT;
#ifdef MSDOSFS_DEBUG
		kprintf("msdosfs_lookup(): looking for . or .. in root directory\n");
#endif
		cluster = MSDOSFSROOT;
		blkoff = MSDOSFSROOT_OFS;
		goto foundroot;
	}
	switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
	    cnp->cn_namelen, 0, pmp)) {
	case 0:
		return (EINVAL);
	case 1:
		break;
	case 2:
		wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
		    cnp->cn_namelen, pmp) + 1;
		break;
	case 3:
		olddos = 0;
		wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
		    cnp->cn_namelen, pmp) + 1;
		break;
	}
	if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) {
		wincnt = 1;
		olddos = 1;
	}
	unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen);

	/*
	 * Suppress search for slots unless creating
	 * file and at end of pathname, in which case
	 * we watch for a place to put the new file in
	 * case it doesn't already exist.
	 */
	slotcount = wincnt;
	if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME)
		slotcount = 0;

#ifdef MSDOSFS_DEBUG
	kprintf("msdosfs_lookup(): dos version of filename %s, length %ld\n",
	    dosfilename, cnp->cn_namelen);
#endif
	/*
	 * Search the directory pointed at by vdp for the name pointed at
	 * by cnp->cn_nameptr.
	 */
	tdp = NULL;
	mbnambuf_init(&nb);
	/*
	 * The outer loop ranges over the clusters that make up the
	 * directory.  Note that the root directory is different from all
	 * other directories.  It has a fixed number of blocks that are not
	 * part of the pool of allocatable clusters.  So, we treat it a
	 * little differently. The root directory starts at "cluster" 0.
	 */
	diroff = 0;
	for (frcn = 0;; frcn++) {
		error = pcbmap(dp, frcn, &bn, &cluster, &blsize);
		if (error) {
			if (error == E2BIG)
				break;
			return (error);
		}
		error = bread(pmp->pm_devvp, de_bntodoff(pmp, bn), blsize, &bp);
		if (error) {
			brelse(bp);
			return (error);
		}
		for (blkoff = 0; blkoff < blsize;
		     blkoff += sizeof(struct direntry),
		     diroff += sizeof(struct direntry)) {
			dep = (struct direntry *)(bp->b_data + blkoff);
			/*
			 * If the slot is empty and we are still looking
			 * for an empty then remember this one.  If the
			 * slot is not empty then check to see if it
			 * matches what we are looking for.  If the slot
			 * has never been filled with anything, then the
			 * remainder of the directory has never been used,
			 * so there is no point in searching it.
			 */
			if (dep->deName[0] == SLOT_EMPTY ||
			    dep->deName[0] == SLOT_DELETED) {
				/*
				 * Drop memory of previous long matches
				 */
				chksum = -1;
				mbnambuf_init(&nb);

				if (slotcount < wincnt) {
					slotcount++;
					slotoffset = diroff;
				}
				if (dep->deName[0] == SLOT_EMPTY) {
					brelse(bp);
					goto notfound;
				}
			} else {
				/*
				 * If there wasn't enough space for our winentries,
				 * forget about the empty space
				 */
				if (slotcount < wincnt)
					slotcount = 0;

				/*
				 * Check for Win95 long filename entry
				 */
				if (dep->deAttributes == ATTR_WIN95) {
				if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
						continue;
					chksum = win2unixfn(&nb,
                                            (struct winentry *)dep, chksum,
                                            pmp);
					continue;
				}

                                chksum = winChkName(&nb,
                                    (const u_char *)cnp->cn_nameptr, unlen,
                                    chksum, pmp);
				if (chksum == -2) {
                                        chksum = -1;
                                        continue;
                                }

				/*
				 * Ignore volume labels (anywhere, not just
				 * the root directory).
				 */
				if (dep->deAttributes & ATTR_VOLUME) {
					chksum = -1;
					continue;
				}

				/*
				 * Check for a checksum or name match
				 */
				if (chksum != winChksum(dep->deName)
				    && (!olddos || bcmp(dosfilename, dep->deName, 11))) {
					chksum = -1;
					continue;
				}
#ifdef MSDOSFS_DEBUG
				kprintf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
				    blkoff, diroff);
#endif
				/*
				 * Remember where this directory
				 * entry came from for whoever did
				 * this lookup.
				 */
				dp->de_fndoffset = diroff;
				dp->de_fndcnt = wincnt - 1;

				goto found;
			}
		}	/* for (blkoff = 0; .... */
		/*
		 * Release the buffer holding the directory cluster just
		 * searched.
		 */
		brelse(bp);
	}	/* for (frcn = 0; ; frcn++) */

notfound:
	/*
	 * We hold no disk buffers at this point.
	 */

	/*
	 * Fixup the slot description to point to the place where
	 * we might put the new DOS direntry (putting the Win95
	 * long name entries before that)
	 */
	if (!slotcount) {
		slotcount = 1;
		slotoffset = diroff;
	}
	if (wincnt > slotcount)
		slotoffset += sizeof(struct direntry) * (wincnt - slotcount);

	/*
	 * If we get here we didn't find the entry we were looking for. But
	 * that's ok if we are creating or renaming and are at the end of
	 * the pathname and the directory hasn't been removed.
	 */
#ifdef MSDOSFS_DEBUG
	kprintf("msdosfs_lookup(): op %d, refcnt %ld\n",
	    nameiop, dp->de_refcnt);
	kprintf("               slotcount %d, slotoffset %d\n",
	       slotcount, slotoffset);
#endif
	if ((nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME) &&
	    dp->de_refcnt > 0) {
		/*
		 * Access for write is interpreted as allowing
		 * creation of files in the directory.
		 */
		error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred);
		if (error)
			return (error);
		/*
		 * Return an indication of where the new directory
		 * entry should be put.
		 */
		dp->de_fndoffset = slotoffset;
		dp->de_fndcnt = wincnt - 1;

		/*
		 * 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.
		 */
		if (!lockparent) {
			vn_unlock(vdp);
			cnp->cn_flags |= CNP_PDIRUNLOCK;
		}
		return (EJUSTRETURN);
	}
	return (ENOENT);

found:
	/*
	 * NOTE:  We still have the buffer with matched directory entry at
	 * this point.
	 */
	isadir = dep->deAttributes & ATTR_DIRECTORY;
	scn = getushort(dep->deStartCluster);
	if (FAT32(pmp)) {
		scn |= getushort(dep->deHighClust) << 16;
		if (scn == pmp->pm_rootdirblk) {
			/*
			 * There should actually be 0 here.
			 * Just ignore the error.
			 */
			scn = MSDOSFSROOT;
		}
	}

	if (isadir) {
		cluster = scn;
		if (cluster == MSDOSFSROOT)
			blkoff = MSDOSFSROOT_OFS;
		else
			blkoff = 0;
	} else if (cluster == MSDOSFSROOT)
		blkoff = diroff;

	/*
	 * Now release buf to allow deget to read the entry again.
	 * Reserving it here and giving it to deget could result
	 * in a deadlock.
	 */
	brelse(bp);
	bp = NULL;
	
foundroot:
	/*
	 * If we entered at foundroot, then we are looking for the . or ..
	 * entry of the filesystems root directory.  isadir and scn were
	 * setup before jumping here.  And, bp is already null.
	 */
	if (FAT32(pmp) && scn == MSDOSFSROOT)
		scn = pmp->pm_rootdirblk;

	/*
	 * 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 == NAMEI_DELETE) {
		/*
		 * Don't allow deleting the root.
		 */
		if (blkoff == MSDOSFSROOT_OFS)
			return EROFS;				/* really? XXX */

		/*
		 * Write access to directory required to delete files.
		 */
		error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred);
		if (error)
			return (error);

		/*
		 * Return pointer to current entry in dp->i_offset.
		 * Save directory inode pointer in ndp->ni_dvp for dirremove().
		 */
		if (dp->de_StartCluster == scn && isadir) {	/* "." */
			vref(vdp);
			*vpp = vdp;
			return (0);
		}
		error = deget(pmp, cluster, blkoff, &tdp);
		if (error)
			return (error);
		*vpp = DETOV(tdp);
		if (!lockparent) {
			vn_unlock(vdp);
			cnp->cn_flags |= CNP_PDIRUNLOCK;
		}
		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 == NAMEI_RENAME && wantparent) {
		if (blkoff == MSDOSFSROOT_OFS)
			return EROFS;			/* really? XXX */

		error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred);
		if (error)
			return (error);

		/*
		 * Careful about locking second inode.
		 * This can only occur if the target is ".".
		 */
		if (dp->de_StartCluster == scn && isadir)
			return (EISDIR);

		if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
			return (error);
		*vpp = DETOV(tdp);
		if (!lockparent) {
			vn_unlock(vdp);
			cnp->cn_flags |= CNP_PDIRUNLOCK;
		}
		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 & CNP_ISDOTDOT) {
		vn_unlock(pdp);
		cnp->cn_flags |= CNP_PDIRUNLOCK;
		error = deget(pmp, cluster, blkoff,  &tdp);
		if (error) {
			vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY); 
			cnp->cn_flags &= ~CNP_PDIRUNLOCK;
			return (error);
		}
		if (lockparent) {
			error = vn_lock(pdp, LK_EXCLUSIVE | LK_FAILRECLAIM);
			if (error) {
				vput(DETOV(tdp));
				return (error);
			}
			cnp->cn_flags &= ~CNP_PDIRUNLOCK;
		}
		*vpp = DETOV(tdp);
	} else if (dp->de_StartCluster == scn && isadir) {
		vref(vdp);	/* we want ourself, ie "." */
		*vpp = vdp;
	} else {
		if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
			return (error);
		if (!lockparent) {
			vn_unlock(pdp);
			cnp->cn_flags |= CNP_PDIRUNLOCK;
		}
		*vpp = DETOV(tdp);
	}
	return (0);
}
Exemple #8
0
/*
 * Truncate the file described by dep to the length specified by length.
 */
int
detrunc(struct denode *dep, u_long length, int flags, struct ucred *cred)
{
	int error;
	int allerror;
	u_long eofentry;
	u_long chaintofree;
	daddr_t bn;
	int boff;
	int isadir = dep->de_Attributes & ATTR_DIRECTORY;
	struct buf *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 vnode 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 ((DETOV(dep)->v_vflag & VV_ROOT) && !FAT32(pmp)) {
#ifdef MSDOSFS_DEBUG
		printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n",
		    dep->de_dirclust, dep->de_diroffset);
#endif
		return (EINVAL);
	}

	if (dep->de_FileSize < length) {
		vnode_pager_setsize(DETOV(dep), length);
		return deextend(dep, length, cred);
	}

	/*
	 * 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, de_clcount(pmp, length) - 1, 0, 
			       &eofentry, 0);
		if (error) {
#ifdef MSDOSFS_DEBUG
			printf("detrunc(): pcbmap fails %d\n", error);
#endif
			return (error);
		}
	}

	fc_purge(dep, de_clcount(pmp, length));

	/*
	 * 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, bn, pmp->pm_bpcluster,
			    NOCRED, &bp);
			if (error) {
				brelse(bp);
#ifdef MSDOSFS_DEBUG
				printf("detrunc(): bread fails %d\n", error);
#endif
				return (error);
			}
			bzero(bp->b_data + boff, 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;
	allerror = vtruncbuf(DETOV(dep), cred, length, pmp->pm_bpcluster);
#ifdef MSDOSFS_DEBUG
	if (allerror)
		printf("detrunc(): vtruncbuf error %d\n", allerror);
#endif
	error = deupdat(dep, !DOINGASYNC((DETOV(dep))));
	if (error != 0 && allerror == 0)
		allerror = error;
#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 != ~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);
		}
		fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1),
			    eofentry);
	}

	/*
	 * Now free the clusters removed from the file because of the
	 * truncation.
	 */
	if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree))
		freeclusterchain(pmp, chaintofree);

	return (allerror);
}
/*
 * When we search a directory the blocks containing directory entries are
 * read and examined.  The directory entries contain information that would
 * normally be in the inode of a unix filesystem.  This means that some of
 * a directory's contents may also be in memory resident denodes (sort of
 * an inode).  This can cause problems if we are searching while some other
 * process is modifying a directory.  To prevent one process from accessing
 * incompletely modified directory information we depend upon being the
 * sole owner of a directory block.  bread/brelse provide this service.
 * This being the case, when a process modifies a directory it must first
 * acquire the disk block that contains the directory entry to be modified.
 * Then update the disk block and the denode, and then write the disk block
 * out to disk.  This way disk blocks containing directory entries and in
 * memory denode's will be in synch.
 */
int
msdosfs_lookup(void *v)
{
	struct vop_lookup_v2_args /* {
		struct vnode *a_dvp;
		struct vnode **a_vpp;
		struct componentname *a_cnp;
	} */ *ap = v;
	struct vnode *vdp = ap->a_dvp;
	struct vnode **vpp = ap->a_vpp;
	struct componentname *cnp = ap->a_cnp;
	daddr_t bn;
	int error;
	int slotcount;
	int slotoffset = 0;
	int frcn;
	u_long cluster;
	int blkoff;
	int diroff;
	int blsize;
	int isadir;		/* ~0 if found direntry is a directory	 */
	u_long scn;		/* starting cluster number		 */
	struct vnode *pdp;
	struct denode *dp;
	struct denode *tdp;
	struct msdosfsmount *pmp;
	struct buf *bp = 0;
	struct direntry *dep;
	u_char dosfilename[12];
	int flags;
	int nameiop = cnp->cn_nameiop;
	int wincnt = 1;
	int chksum = -1, chksum_ok;
	int olddos = 1;

	flags = cnp->cn_flags;

#ifdef MSDOSFS_DEBUG
	printf("msdosfs_lookup(): looking for %.*s\n",
		(int)cnp->cn_namelen, cnp->cn_nameptr);
#endif
	dp = VTODE(vdp);
	pmp = dp->de_pmp;
	*vpp = NULL;
#ifdef MSDOSFS_DEBUG
	printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n",
	    vdp, dp, dp->de_Attributes);
#endif

	/*
	 * Check accessiblity of directory.
	 */
	if ((error = VOP_ACCESS(vdp, VEXEC, cnp->cn_cred)) != 0)
		return (error);

	if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) &&
	    (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
		return (EROFS);

	/*
	 * We now have a segment name to search for, and a directory to search.
	 *
	 * Before tediously performing a linear scan of the directory,
	 * check the name cache to see if the directory/name pair
	 * we are looking for is known already.
	 */
	if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen,
			 cnp->cn_nameiop, cnp->cn_flags, NULL, vpp)) {
		return *vpp == NULLVP ? ENOENT: 0;
	}

	/*
	 * If they are going after the . or .. entry in the root directory,
	 * they won't find it.  DOS filesystems don't have them in the root
	 * directory.  So, we fake it. deget() is in on this scam too.
	 */
	if ((vdp->v_vflag & VV_ROOT) && cnp->cn_nameptr[0] == '.' &&
	    (cnp->cn_namelen == 1 ||
		(cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
		isadir = ATTR_DIRECTORY;
		scn = MSDOSFSROOT;
#ifdef MSDOSFS_DEBUG
		printf("msdosfs_lookup(): looking for . or .. in root directory\n");
#endif
		cluster = MSDOSFSROOT;
		blkoff = MSDOSFSROOT_OFS;
		goto foundroot;
	}

	switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
	    cnp->cn_namelen, 0)) {
	case 0:
		return (EINVAL);
	case 1:
		break;
	case 2:
		wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
		    cnp->cn_namelen) + 1;
		break;
	case 3:
		olddos = 0;
		wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
		    cnp->cn_namelen) + 1;
		break;
	}
	if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
		wincnt = 1;

	/*
	 * Suppress search for slots unless creating
	 * file and at end of pathname, in which case
	 * we watch for a place to put the new file in
	 * case it doesn't already exist.
	 */
	slotcount = wincnt;
	if ((nameiop == CREATE || nameiop == RENAME) &&
	    (flags & ISLASTCN))
		slotcount = 0;

#ifdef MSDOSFS_DEBUG
	printf("msdosfs_lookup(): dos filename: %s\n", dosfilename);
#endif
	/*
	 * Search the directory pointed at by vdp for the name pointed at
	 * by cnp->cn_nameptr.
	 */
	tdp = NULL;
	/*
	 * The outer loop ranges over the clusters that make up the
	 * directory.  Note that the root directory is different from all
	 * other directories.  It has a fixed number of blocks that are not
	 * part of the pool of allocatable clusters.  So, we treat it a
	 * little differently. The root directory starts at "cluster" 0.
	 */
	diroff = 0;
	for (frcn = 0; diroff < dp->de_FileSize; frcn++) {
		if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) {
			if (error == E2BIG)
				break;
			return (error);
		}
		error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED,
		    0, &bp);
		if (error) {
			return (error);
		}
		for (blkoff = 0; blkoff < blsize;
		     blkoff += sizeof(struct direntry),
		     diroff += sizeof(struct direntry)) {
			dep = (struct direntry *)((char *)bp->b_data + blkoff);
			/*
			 * If the slot is empty and we are still looking
			 * for an empty then remember this one.  If the
			 * slot is not empty then check to see if it
			 * matches what we are looking for.  If the slot
			 * has never been filled with anything, then the
			 * remainder of the directory has never been used,
			 * so there is no point in searching it.
			 */
			if (dep->deName[0] == SLOT_EMPTY ||
			    dep->deName[0] == SLOT_DELETED) {
				/*
				 * Drop memory of previous long matches
				 */
				chksum = -1;

				if (slotcount < wincnt) {
					slotcount++;
					slotoffset = diroff;
				}
				if (dep->deName[0] == SLOT_EMPTY) {
					brelse(bp, 0);
					goto notfound;
				}
			} else {
				/*
				 * If there wasn't enough space for our
				 * winentries, forget about the empty space
				 */
				if (slotcount < wincnt)
					slotcount = 0;

				/*
				 * Check for Win95 long filename entry
				 */
				if (dep->deAttributes == ATTR_WIN95) {
					if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
						continue;

					chksum = winChkName((const u_char *)cnp->cn_nameptr,
							    cnp->cn_namelen,
							    (struct winentry *)dep,
							    chksum);
					continue;
				}

				/*
				 * Ignore volume labels (anywhere, not just
				 * the root directory).
				 */
				if (dep->deAttributes & ATTR_VOLUME) {
					chksum = -1;
					continue;
				}

				/*
				 * Check for a checksum or name match
				 */
				chksum_ok = (chksum == winChksum(dep->deName));
				if (!chksum_ok && (
					!olddos ||
					memcmp(&dosfilename[0],dep->deName,8) ||
					memcmp(&dosfilename[8],dep->deExtension,3))) {
					chksum = -1;
					continue;
				}
#ifdef MSDOSFS_DEBUG
				printf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
				    blkoff, diroff);
#endif
				/*
				 * Remember where this directory
				 * entry came from for whoever did
				 * this lookup.
				 */
				dp->de_fndoffset = diroff;
				if (chksum_ok && nameiop == RENAME) {
					/*
					 * Target had correct long name
					 * directory entries, reuse them
					 * as needed.
					 */
					dp->de_fndcnt = wincnt - 1;
				} else {
					/*
					 * Long name directory entries
					 * not present or corrupt, can only
					 * reuse dos directory entry.
					 */
					dp->de_fndcnt = 0;
				}

				goto found;
			}
		}	/* for (blkoff = 0; .... */
		/*
		 * Release the buffer holding the directory cluster just
		 * searched.
		 */
		brelse(bp, 0);
	}	/* for (frcn = 0; ; frcn++) */

notfound:
	/*
	 * We hold no disk buffers at this point.
	 */

	/*
	 * If we get here we didn't find the entry we were looking for. But
	 * that's ok if we are creating or renaming and are at the end of
	 * the pathname and the directory hasn't been removed.
	 */
#ifdef MSDOSFS_DEBUG
	printf("msdosfs_lookup(): op %d, refcnt %ld, slotcount %d, slotoffset %d\n",
	    nameiop, dp->de_refcnt, slotcount, slotoffset);
#endif
	if ((nameiop == CREATE || nameiop == RENAME) &&
	    (flags & ISLASTCN) && dp->de_refcnt != 0) {
		/*
		 * Access for write is interpreted as allowing
		 * creation of files in the directory.
		 */
		error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred);
		if (error)
			return (error);

		/*
		 * Fixup the slot description to point to the place where
		 * we might put the new DOS direntry (putting the Win95
		 * long name entries before that)
		 */
		if (!slotcount) {
			slotcount = 1;
			slotoffset = diroff;
		}
		if (wincnt > slotcount) {
			slotoffset +=
				sizeof(struct direntry) * (wincnt - slotcount);
		}

		/*
		 * Return an indication of where the new directory
		 * entry should be put.
		 */
		dp->de_fndoffset = slotoffset;
		dp->de_fndcnt = wincnt - 1;

		/*
		 * 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.
		 *
		 * NB - if the directory is unlocked, then this
		 * information cannot be used.
		 */
		return (EJUSTRETURN);
	}

#if 0
	/*
	 * Insert name into cache (as non-existent) if appropriate.
	 *
	 * XXX Negative caching is broken for msdosfs because the name
	 * cache doesn't understand peculiarities such as case insensitivity
	 * and 8.3 filenames.  Hence, it may not invalidate all negative
	 * entries if a file with this name is later created.
	 * e.g. creating a file 'foo' won't invalidate a negative entry 
	 * for 'FOO'.
	 */
	if (nameiop != CREATE)
		cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen,
			    cnp->cn_flags);
#endif

	return (ENOENT);

found:
	/*
	 * NOTE:  We still have the buffer with matched directory entry at
	 * this point.
	 */
	isadir = dep->deAttributes & ATTR_DIRECTORY;
	scn = getushort(dep->deStartCluster);
	if (FAT32(pmp)) {
		scn |= getushort(dep->deHighClust) << 16;
		if (scn == pmp->pm_rootdirblk) {
			/*
			 * There should actually be 0 here.
			 * Just ignore the error.
			 */
			scn = MSDOSFSROOT;
		}
	}

	if (isadir) {
		cluster = scn;
		if (cluster == MSDOSFSROOT)
			blkoff = MSDOSFSROOT_OFS;
		else
			blkoff = 0;
	} else if (cluster == MSDOSFSROOT)
		blkoff = diroff;

	/*
	 * Now release buf to allow deget to read the entry again.
	 * Reserving it here and giving it to deget could result
	 * in a deadlock.
	 */
	brelse(bp, 0);

foundroot:
	/*
	 * If we entered at foundroot, then we are looking for the . or ..
	 * entry of the filesystems root directory.  isadir and scn were
	 * setup before jumping here.  And, bp is already null.
	 */
	if (FAT32(pmp) && scn == MSDOSFSROOT)
		scn = pmp->pm_rootdirblk;

	/*
	 * If deleting, and at end of pathname, return
	 * parameters which can be used to remove file.
	 * Lock the inode, being careful with ".".
	 */
	if (nameiop == DELETE && (flags & ISLASTCN)) {
		/*
		 * Don't allow deleting the root.
		 */
		if (blkoff == MSDOSFSROOT_OFS)
			return EINVAL;

		/*
		 * Write access to directory required to delete files.
		 */
		error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred);
		if (error)
			return (error);

		/*
		 * Return pointer to current entry in dp->i_offset.
		 * Save directory inode pointer in ndp->ni_dvp for dirremove().
		 */
		if (dp->de_StartCluster == scn && isadir) {	/* "." */
			vref(vdp);
			*vpp = vdp;
			return (0);
		}
		if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
			return (error);
		*vpp = DETOV(tdp);
		VOP_UNLOCK(*vpp);
		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 && (flags & ISLASTCN)) {

		if (vdp->v_mount->mnt_flag & MNT_RDONLY)
			return (EROFS);

		if (blkoff == MSDOSFSROOT_OFS)
			return EINVAL;

		error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred);
		if (error)
			return (error);

		/*
		 * Careful about locking second inode.
		 * This can only occur if the target is ".".
		 */
		if (dp->de_StartCluster == scn && isadir)
			return (EISDIR);

		if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
			return (error);
		*vpp = DETOV(tdp);
		VOP_UNLOCK(*vpp);
		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);	/* race to get the inode */
		error = deget(pmp, cluster, blkoff, &tdp);
		vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY);
		if (error) {
			return error;
		}
		*vpp = DETOV(tdp);
	} else if (dp->de_StartCluster == scn && isadir) {
		vref(vdp);	/* we want ourself, ie "." */
		*vpp = vdp;
	} else {
		if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
			return (error);
		*vpp = DETOV(tdp);
	}

	/*
	 * Insert name into cache if appropriate.
	 */
	cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags);

	if (*vpp != vdp)
		VOP_UNLOCK(*vpp);

	return 0;
}
/*
 * 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 buf *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_vnode = 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 vnode.
	 */
	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_vnode = (struct vnode *)-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 vnode 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);
}
Exemple #11
0
/*
 * Renames on files require moving the denode to a new hash queue since the
 * denode's location is used to compute which hash queue to put the file
 * in. Unless it is a rename in place.  For example "mv a b".
 *
 * What follows is the basic algorithm:
 *
 * if (file move) {
 *	if (dest file exists) {
 *		remove dest file
 *	}
 *	if (dest and src in same directory) {
 *		rewrite name in existing directory slot
 *	} else {
 *		write new entry in dest directory
 *		update offset and dirclust in denode
 *		move denode to new hash chain
 *		clear old directory entry
 *	}
 * } else {
 *	directory move
 *	if (dest directory exists) {
 *		if (dest is not empty) {
 *			return ENOTEMPTY
 *		}
 *		remove dest directory
 *	}
 *	if (dest and src in same directory) {
 *		rewrite name in existing entry
 *	} else {
 *		be sure dest is not a child of src directory
 *		write entry in dest directory
 *		update "." and ".." in moved directory
 *		update offset and dirclust in denode
 *		move denode to new hash chain
 *		clear old directory entry for moved directory
 *	}
 * }
 *
 * On entry:
 *	source's parent directory is unlocked
 *	source file or directory is unlocked
 *	destination's parent directory is locked
 *	destination file or directory is locked if it exists
 *
 * On exit:
 *	all denodes should be released
 *
 * Notes:
 * I'm not sure how the memory containing the pathnames pointed at by the
 * componentname structures is freed, there may be some memory bleeding
 * for each rename done.
 */
int
msdosfs_rename(void *v)
{
	struct vop_rename_args *ap = v;
	struct vnode *tvp = ap->a_tvp;
	struct vnode *tdvp = ap->a_tdvp;
	struct vnode *fvp = ap->a_fvp;
	struct vnode *fdvp = ap->a_fdvp;
	struct componentname *tcnp = ap->a_tcnp;
	struct componentname *fcnp = ap->a_fcnp;
	struct proc *p = curproc; /* XXX */
	struct denode *ip, *xp, *dp, *zp;
	u_char toname[11], oldname[11];
	uint32_t from_diroffset, to_diroffset;
	u_char to_count;
	int doingdirectory = 0, newparent = 0;
	int error;
	uint32_t cn, pcl;
	daddr64_t bn;
	struct msdosfsmount *pmp;
	struct direntry *dotdotp;
	struct buf *bp;

	pmp = VFSTOMSDOSFS(fdvp->v_mount);

#ifdef DIAGNOSTIC
	if ((tcnp->cn_flags & HASBUF) == 0 ||
	    (fcnp->cn_flags & HASBUF) == 0)
		panic("msdosfs_rename: no name");
#endif
	/*
	 * Check for cross-device rename.
	 */
	if ((fvp->v_mount != tdvp->v_mount) ||
	    (tvp && (fvp->v_mount != tvp->v_mount))) {
		error = EXDEV;
abortit:
		VOP_ABORTOP(tdvp, tcnp);
		if (tdvp == tvp)
			vrele(tdvp);
		else
			vput(tdvp);
		if (tvp)
			vput(tvp);
		VOP_ABORTOP(fdvp, fcnp);
		vrele(fdvp);
		vrele(fvp);
		return (error);
	}
	
	/*
	 * If source and dest are the same, do nothing.
	 */
	if (tvp == fvp) {
		error = 0;
		goto abortit;
	}

	/* */
	if ((error = vn_lock(fvp, LK_EXCLUSIVE | LK_RETRY, p)) != 0)
		goto abortit;
	dp = VTODE(fdvp);
	ip = VTODE(fvp);

	/*
	 * Be sure we are not renaming ".", "..", or an alias of ".". This
	 * leads to a crippled directory tree.  It's pretty tough to do a
	 * "ls" or "pwd" with the "." directory entry missing, and "cd .."
	 * doesn't work if the ".." entry is missing.
	 */
	if (ip->de_Attributes & ATTR_DIRECTORY) {
		/*
		 * Avoid ".", "..", and aliases of "." for obvious reasons.
		 */
		if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
		    dp == ip ||
		    (fcnp->cn_flags & ISDOTDOT) ||
		    (tcnp->cn_flags & ISDOTDOT) ||
		    (ip->de_flag & DE_RENAME)) {
			VOP_UNLOCK(fvp, 0, p);
			error = EINVAL;
			goto abortit;
		}
		ip->de_flag |= DE_RENAME;
		doingdirectory++;
	}

	/*
	 * When the target exists, both the directory
	 * and target vnodes are returned locked.
	 */
	dp = VTODE(tdvp);
	xp = tvp ? VTODE(tvp) : NULL;
	/*
	 * Remember direntry place to use for destination
	 */
	to_diroffset = dp->de_fndoffset;
	to_count = dp->de_fndcnt;

	/*
	 * If ".." must be changed (ie the directory gets a new
	 * parent) then the source directory must not be in the
	 * directory hierarchy above the target, as this would
	 * orphan everything below the source directory. Also
	 * the user must have write permission in the source so
	 * as to be able to change "..". We must repeat the call
	 * to namei, as the parent directory is unlocked by the
	 * call to doscheckpath().
	 */
	error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_proc);
	VOP_UNLOCK(fvp, 0, p);
	if (VTODE(fdvp)->de_StartCluster != VTODE(tdvp)->de_StartCluster)
		newparent = 1;
	vrele(fdvp);
	if (doingdirectory && newparent) {
		if (error)	/* write access check above */
			goto bad1;
		if (xp != NULL)
			vput(tvp);
		/*
		 * doscheckpath() vput()'s dp,
		 * so we have to do a relookup afterwards
		 */
		if ((error = doscheckpath(ip, dp)) != 0)
			goto out;
		if ((tcnp->cn_flags & SAVESTART) == 0)
			panic("msdosfs_rename: lost to startdir");
		if ((error = vfs_relookup(tdvp, &tvp, tcnp)) != 0)
			goto out;
		dp = VTODE(tdvp);
		xp = tvp ? VTODE(tvp) : NULL;
	}

	if (xp != NULL) {
		/*
		 * Target must be empty if a directory and have no links
		 * to it. Also, ensure source and target are compatible
		 * (both directories, or both not directories).
		 */
		if (xp->de_Attributes & ATTR_DIRECTORY) {
			if (!dosdirempty(xp)) {
				error = ENOTEMPTY;
				goto bad1;
			}
			if (!doingdirectory) {
				error = ENOTDIR;
				goto bad1;
			}
			cache_purge(tdvp);
		} else if (doingdirectory) {
			error = EISDIR;
			goto bad1;
		}
		if ((error = removede(dp, xp)) != 0)
			goto bad1;
		vput(tvp);
		xp = NULL;
	}

	/*
	 * Convert the filename in tcnp into a dos filename. We copy this
	 * into the denode and directory entry for the destination
	 * file/directory.
	 */
	if ((error = uniqdosname(VTODE(tdvp), tcnp, toname)) != 0)
		goto bad1;

	/*
	 * Since from wasn't locked at various places above,
	 * have to do a relookup here.
	 */
	fcnp->cn_flags &= ~MODMASK;
	fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
	if ((fcnp->cn_flags & SAVESTART) == 0)
		panic("msdosfs_rename: lost from startdir");
	if (!newparent)
		VOP_UNLOCK(tdvp, 0, p);
	(void) vfs_relookup(fdvp, &fvp, fcnp);
	if (fvp == NULL) {
		/*
		 * From name has disappeared.
		 */
		if (doingdirectory)
			panic("rename: lost dir entry");
		vrele(ap->a_fvp);
		if (newparent)
			VOP_UNLOCK(tdvp, 0, p);
		vrele(tdvp);
		return 0;
	}
	xp = VTODE(fvp);
	zp = VTODE(fdvp);
	from_diroffset = zp->de_fndoffset;

	/*
	 * Ensure that the directory entry still exists and has not
	 * changed till now. If the source is a file the entry may
	 * have been unlinked or renamed. In either case there is
	 * no further work to be done. If the source is a directory
	 * then it cannot have been rmdir'ed or renamed; this is
	 * prohibited by the DE_RENAME flag.
	 */
	if (xp != ip) {
		if (doingdirectory)
			panic("rename: lost dir entry");
		vrele(ap->a_fvp);
		if (newparent)
			VOP_UNLOCK(fdvp, 0, p);
		xp = NULL;
	} else {
		vrele(fvp);
		xp = NULL;

		/*
		 * First write a new entry in the destination
		 * directory and mark the entry in the source directory
		 * as deleted.  Then move the denode to the correct hash
		 * chain for its new location in the filesystem.  And, if
		 * we moved a directory, then update its .. entry to point
		 * to the new parent directory.
		 */
		bcopy(ip->de_Name, oldname, 11);
		bcopy(toname, ip->de_Name, 11);	/* update denode */
		dp->de_fndoffset = to_diroffset;
		dp->de_fndcnt = to_count;
		error = createde(ip, dp, (struct denode **)0, tcnp);
		if (error) {
			bcopy(oldname, ip->de_Name, 11);
			if (newparent)
				VOP_UNLOCK(fdvp, 0, p);
			goto bad;
		}
		ip->de_refcnt++;
		zp->de_fndoffset = from_diroffset;
		if ((error = removede(zp, ip)) != 0) {
			/* XXX should really panic here, fs is corrupt */
			if (newparent)
				VOP_UNLOCK(fdvp, 0, p);
			goto bad;
		}

		cache_purge(fvp);

		if (!doingdirectory) {
			error = pcbmap(dp, de_cluster(pmp, to_diroffset), 0,
				       &ip->de_dirclust, 0);
			if (error) {
				/* XXX should really panic here, fs is corrupt */
				if (newparent)
					VOP_UNLOCK(fdvp, 0, p);
				goto bad;
			}
			if (ip->de_dirclust != MSDOSFSROOT)
				ip->de_diroffset = to_diroffset & pmp->pm_crbomask;
		}
		reinsert(ip);
		if (newparent)
			VOP_UNLOCK(fdvp, 0, p);
	}

	/*
	 * If we moved a directory to a new parent directory, then we must
	 * fixup the ".." entry in the moved directory.
	 */
	if (doingdirectory && newparent) {
		cn = ip->de_StartCluster;
		if (cn == MSDOSFSROOT) {
			/* this should never happen */
			panic("msdosfs_rename: updating .. in root directory?");
		} else
			bn = cntobn(pmp, cn);
		error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
			      NOCRED, &bp);
		if (error) {
			/* XXX should really panic here, fs is corrupt */
			brelse(bp);
			goto bad;
		}
		dotdotp = (struct direntry *)bp->b_data;
		putushort(dotdotp[0].deStartCluster, cn);
		pcl = dp->de_StartCluster;
		if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
			pcl = 0;
		putushort(dotdotp[1].deStartCluster, pcl);
		if (FAT32(pmp)) {
			putushort(dotdotp[0].deHighClust, cn >> 16);
			putushort(dotdotp[1].deHighClust, pcl >> 16);
		}
		if ((error = bwrite(bp)) != 0) {
			/* XXX should really panic here, fs is corrupt */
			goto bad;
		}
	}
Exemple #12
0
/*
 * Write data to a file or directory.
 */
int
msdosfs_write(void *v)
{
	struct vop_write_args *ap = v;
	int n;
	int croffset;
	int resid;
	uint32_t osize;
	int error = 0;
	uint32_t count, lastcn;
	daddr64_t bn;
	struct buf *bp;
	int ioflag = ap->a_ioflag;
	struct uio *uio = ap->a_uio;
	struct proc *p = uio->uio_procp;
	struct vnode *vp = ap->a_vp;
	struct vnode *thisvp;
	struct denode *dep = VTODE(vp);
	struct msdosfsmount *pmp = dep->de_pmp;
	struct ucred *cred = ap->a_cred;

#ifdef MSDOSFS_DEBUG
	printf("msdosfs_write(vp %08x, uio %08x, ioflag %08x, cred %08x\n",
	    vp, uio, ioflag, cred);
	printf("msdosfs_write(): diroff %d, dirclust %d, startcluster %d\n",
	    dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
#endif

	switch (vp->v_type) {
	case VREG:
		if (ioflag & IO_APPEND)
			uio->uio_offset = dep->de_FileSize;
		thisvp = vp;
		break;
	case VDIR:
		return EISDIR;
	default:
		panic("msdosfs_write(): bad file type");
	}

	if (uio->uio_offset < 0)
		return (EINVAL);

	if (uio->uio_resid == 0)
		return (0);

	/* Don't bother to try to write files larger than the f/s limit */
	if (uio->uio_offset + uio->uio_resid > MSDOSFS_FILESIZE_MAX)
		return (EFBIG);

	/*
	 * If they've exceeded their filesize limit, tell them about it.
	 */
	if (p &&
	    ((uio->uio_offset + uio->uio_resid) >
	    p->p_rlimit[RLIMIT_FSIZE].rlim_cur)) {
		psignal(p, SIGXFSZ);
		return (EFBIG);
	}

	/*
	 * If the offset we are starting the write at is beyond the end of
	 * the file, then they've done a seek.  Unix filesystems allow
	 * files with holes in them, DOS doesn't so we must fill the hole
	 * with zeroed blocks.
	 */
	if (uio->uio_offset > dep->de_FileSize) {
		if ((error = deextend(dep, uio->uio_offset, cred)) != 0)
			return (error);
	}

	/*
	 * Remember some values in case the write fails.
	 */
	resid = uio->uio_resid;
	osize = dep->de_FileSize;

	/*
	 * If we write beyond the end of the file, extend it to its ultimate
	 * size ahead of the time to hopefully get a contiguous area.
	 */
	if (uio->uio_offset + resid > osize) {
		count = de_clcount(pmp, uio->uio_offset + resid) -
			de_clcount(pmp, osize);
		if ((error = extendfile(dep, count, NULL, NULL, 0)) &&
		    (error != ENOSPC || (ioflag & IO_UNIT)))
			goto errexit;
		lastcn = dep->de_fc[FC_LASTFC].fc_frcn;
	} else
		lastcn = de_clcount(pmp, osize) - 1;

	do {
		if (de_cluster(pmp, uio->uio_offset) > lastcn) {
			error = ENOSPC;
			break;
		}

		bn = de_blk(pmp, uio->uio_offset);
		if ((uio->uio_offset & pmp->pm_crbomask) == 0
		    && (de_blk(pmp, uio->uio_offset + uio->uio_resid) > de_blk(pmp, uio->uio_offset)
			|| uio->uio_offset + uio->uio_resid >= dep->de_FileSize)) {
			/*
			 * If either the whole cluster gets written,
			 * or we write the cluster from its start beyond EOF,
			 * then no need to read data from disk.
			 */
			bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0);
			clrbuf(bp);
			/*
			 * Do the bmap now, since pcbmap needs buffers
			 * for the fat table. (see msdosfs_strategy)
			 */
			if (bp->b_blkno == bp->b_lblkno) {
				error = pcbmap(dep,
					       de_bn2cn(pmp, bp->b_lblkno),
					       &bp->b_blkno, 0, 0);
				if (error)
					bp->b_blkno = -1;
			}
			if (bp->b_blkno == -1) {
				brelse(bp);
				if (!error)
					error = EIO;		/* XXX */
				break;
			}
		} else {
			/*
			 * The block we need to write into exists, so read it in.
			 */
			error = bread(thisvp, bn, pmp->pm_bpcluster,
				      NOCRED, &bp);
			if (error) {
				brelse(bp);
				break;
			}
		}

		croffset = uio->uio_offset & pmp->pm_crbomask;
		n = min(uio->uio_resid, pmp->pm_bpcluster - croffset);
		if (uio->uio_offset + n > dep->de_FileSize) {
			dep->de_FileSize = uio->uio_offset + n;
			uvm_vnp_setsize(vp, dep->de_FileSize);
		}
		uvm_vnp_uncache(vp);
		/*
		 * Should these vnode_pager_* functions be done on dir
		 * files?
		 */

		/*
		 * Copy the data from user space into the buf header.
		 */
		error = uiomove(bp->b_data + croffset, n, uio);

		/*
		 * If they want this synchronous then write it and wait for
		 * it.  Otherwise, if on a cluster boundary write it
		 * asynchronously so we can move on to the next block
		 * without delay.  Otherwise do a delayed write because we
		 * may want to write somemore into the block later.
		 */
		if (ioflag & IO_SYNC)
			(void) bwrite(bp);
		else if (n + croffset == pmp->pm_bpcluster)
			bawrite(bp);
		else
			bdwrite(bp);
		dep->de_flag |= DE_UPDATE;
	} while (error == 0 && uio->uio_resid > 0);

	/*
	 * If the write failed and they want us to, truncate the file back
	 * to the size it was before the write was attempted.
	 */
errexit:
	if (error) {
		if (ioflag & IO_UNIT) {
			detrunc(dep, osize, ioflag & IO_SYNC, NOCRED, NULL);
			uio->uio_offset -= resid - uio->uio_resid;
			uio->uio_resid = resid;
		} else {
			detrunc(dep, dep->de_FileSize, ioflag & IO_SYNC, NOCRED, NULL);
			if (uio->uio_resid != resid)
				error = 0;
		}
	} else if (ioflag & IO_SYNC)
		error = deupdat(dep, 1);
	return (error);
}
Exemple #13
0
int
msdosfs_read(void *v)
{
	struct vop_read_args *ap = v;
	int error = 0;
	uint32_t diff;
	int blsize;
	int isadir;
	uint32_t n;
	long on;
	daddr64_t lbn, rablock, rablkno;
	struct buf *bp;
	struct vnode *vp = ap->a_vp;
	struct denode *dep = VTODE(vp);
	struct msdosfsmount *pmp = dep->de_pmp;
	struct uio *uio = ap->a_uio;

	/*
	 * If they didn't ask for any data, then we are done.
	 */
	if (uio->uio_resid == 0)
		return (0);
	if (uio->uio_offset < 0)
		return (EINVAL);

	isadir = dep->de_Attributes & ATTR_DIRECTORY;
	do {
		if (uio->uio_offset >= dep->de_FileSize)
			return (0);

		lbn = de_cluster(pmp, uio->uio_offset);
		on = uio->uio_offset & pmp->pm_crbomask;
		n = min((uint32_t) (pmp->pm_bpcluster - on), uio->uio_resid);

		/*
		 * de_FileSize is uint32_t, and we know that uio_offset <
		 * de_FileSize, so uio->uio_offset < 2^32.  Therefore
		 * the cast to uint32_t on the next line is safe.
		 */
		diff = dep->de_FileSize - (uint32_t)uio->uio_offset;
		if (diff < n)
			n = diff;

		/* convert cluster # to block # if a directory */
		if (isadir) {
			error = pcbmap(dep, lbn, &lbn, 0, &blsize);
			if (error)
				return (error);
		}
		/*
		 * If we are operating on a directory file then be sure to
		 * do i/o with the vnode for the filesystem instead of the
		 * vnode for the directory.
		 */
		if (isadir) {
			error = bread(pmp->pm_devvp, lbn, blsize, NOCRED, &bp);
		} else {
			rablock = lbn + 1;
			rablkno = de_cn2bn(pmp, rablock);
			if (dep->de_lastr + 1 == lbn &&
			    de_cn2off(pmp, rablock) < dep->de_FileSize)
				error = breadn(vp, de_cn2bn(pmp, lbn),
				    pmp->pm_bpcluster, &rablkno,
				    &pmp->pm_bpcluster, 1, NOCRED, &bp);
			else
				error = bread(vp, de_cn2bn(pmp, lbn),
				    pmp->pm_bpcluster, NOCRED, &bp);
			dep->de_lastr = lbn;
		}
		n = min(n, pmp->pm_bpcluster - bp->b_resid);
		if (error) {
			brelse(bp);
			return (error);
		}
		error = uiomove(bp->b_data + on, (int) n, uio);
		brelse(bp);
	} while (error == 0 && uio->uio_resid > 0 && n != 0);
	if (!isadir && !(vp->v_mount->mnt_flag & MNT_NOATIME))
		dep->de_flag |= DE_ACCESS;
	return (error);
}
/*
 * 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, rberror;
	u_long dirclust, clusoffset;
	u_long fndoffset, havecnt = 0, wcnt = 1, i;
	struct direntry *ndep;
	struct msdosfsmount *pmp = ddep->de_pmp;
	struct buf *bp;
	daddr_t bn;
	int blsize;
#ifdef _KERNEL
	int async = ddep->de_pmp->pm_mountp->mnt_flag & MNT_ASYNC;
#else
#define async 0
#endif

#ifdef MSDOSFS_DEBUG
	printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
	    dep, ddep, depp, cnp);
#endif

	/*
	 * 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) {
		u_long needlen = ddep->de_fndoffset + sizeof(struct direntry)
		    - ddep->de_FileSize;
		dirclust = de_clcount(pmp, needlen);
		if ((error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR)) != 0) {
			(void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED);
			goto err_norollback;
		}

		/*
		 * 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)
		goto err_norollback;
	clusoffset = ddep->de_fndoffset;
	if (dirclust != MSDOSFSROOT)
		clusoffset &= pmp->pm_crbomask;
	if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED,
	    B_MODIFY, &bp)) != 0) {
		goto err_norollback;
	}
	ndep = bptoep(pmp, bp, clusoffset);

	DE_EXTERNALIZE(ndep, dep);

	/*
	 * Now write the Win95 long name
	 */
	if (ddep->de_fndcnt > 0) {
		u_int8_t chksum = winChksum(ndep->deName);
		const u_char *un = (const u_char *)cnp->cn_nameptr;
		int unlen = cnp->cn_namelen;
		u_long xhavecnt;

		fndoffset = ddep->de_fndoffset;
		xhavecnt = ddep->de_fndcnt + 1;

		for(; wcnt < xhavecnt; wcnt++) {
			if ((fndoffset & pmp->pm_crbomask) == 0) {
				/* we should never get here if ddep is root
				 * directory */

				if (async)
					(void) bdwrite(bp);
				else if ((error = bwrite(bp)) != 0)
					goto rollback;

				fndoffset -= sizeof(struct direntry);
				error = pcbmap(ddep,
					       de_cluster(pmp, fndoffset),
					       &bn, 0, &blsize);
				if (error)
					goto rollback;

				error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
				    blsize, NOCRED, B_MODIFY, &bp);
				if (error) {
					goto rollback;
				}
				ndep = bptoep(pmp, bp,
						fndoffset & pmp->pm_crbomask);
			} else {
				ndep--;
				fndoffset -= sizeof(struct direntry);
			}
			if (!unix2winfn(un, unlen, (struct winentry *)ndep,
						wcnt, chksum))
				break;
		}
	}

	if (async)
		bdwrite(bp);
	else if ((error = bwrite(bp)) != 0)
		goto rollback;

	/*
	 * If they want us to return with the denode gotten.
	 */
	if (depp) {
		u_long diroffset = clusoffset;
		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;
		}
		error = deget(pmp, dirclust, diroffset, depp);
#ifndef MAKEFS
		if (error == 0)
			VOP_UNLOCK(DETOV(*depp));
#endif
		return error;
	}

	return 0;

    rollback:
	/*
	 * Mark all slots modified so far as deleted. Note that we
	 * can't just call removede(), since directory is not in
	 * consistent state.
	 */
	fndoffset = ddep->de_fndoffset;
	rberror = pcbmap(ddep, de_cluster(pmp, fndoffset),
	       &bn, NULL, &blsize);
	if (rberror)
		goto err_norollback;
	if ((rberror = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED,
	    B_MODIFY, &bp)) != 0) {
		goto err_norollback;
	}
	ndep = bptoep(pmp, bp, clusoffset);

	havecnt = ddep->de_fndcnt + 1;
	for(i = wcnt; i <= havecnt; i++) {
		/* mark entry as deleted */
		ndep->deName[0] = SLOT_DELETED;

		if ((fndoffset & pmp->pm_crbomask) == 0) {
			/* we should never get here if ddep is root
			 * directory */

			if (async)
				bdwrite(bp);
			else if ((rberror = bwrite(bp)) != 0)
				goto err_norollback;

			fndoffset -= sizeof(struct direntry);
			rberror = pcbmap(ddep,
				       de_cluster(pmp, fndoffset),
				       &bn, 0, &blsize);
			if (rberror)
				goto err_norollback;

			rberror = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
			    blsize, NOCRED, B_MODIFY, &bp);
			if (rberror) {
				goto err_norollback;
			}
			ndep = bptoep(pmp, bp, fndoffset);
		} else {
			ndep--;
			fndoffset -= sizeof(struct direntry);
		}
	}

	/* ignore any further error */
	if (async)
		(void) bdwrite(bp);
	else
		(void) bwrite(bp);

    err_norollback:
	return error;
}
/*
 * 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, uint32_t dirclust, uint32_t diroffset,
    struct denode **depp)
{
	int error;
	extern struct vops msdosfs_vops;
	struct direntry *direntptr;
	struct denode *ldep;
	struct vnode *nvp;
	struct buf *bp;
	struct proc *p = curproc; /* XXX */

#ifdef MSDOSFS_DEBUG
	printf("deget(pmp %08x, dirclust %d, diroffset %x, depp %08x)\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;

	/*
	 * See if the denode is in the denode cache. Use the location of
	 * the directory entry to compute the hash value. For subdir use
	 * address of "." entry. For root dir (if not FAT32) use cluster
	 * MSDOSFSROOT, offset MSDOSFSROOT_OFS
	 * 
	 * NOTE: The check for de_refcnt > 0 below insures the denode being
	 * examined does not represent an unlinked but still open file.
	 * These files are not to be accessible even when the directory
	 * entry that represented the file happens to be reused while the
	 * deleted file is still open.
	 */
retry:
	ldep = msdosfs_hashget(pmp->pm_dev, dirclust, diroffset);
	if (ldep) {
		*depp = ldep;
		return (0);
	}

	/*
	 * Directory entry was not in cache, have to create a vnode and
	 * copy it from the passed disk buffer.
	 */
	/* getnewvnode() does a vref() on the vnode */
	error = getnewvnode(VT_MSDOSFS, pmp->pm_mountp, &msdosfs_vops, &nvp);
	if (error) {
		*depp = 0;
		return (error);
	}
	ldep = malloc(sizeof(*ldep), M_MSDOSFSNODE, M_WAITOK | M_ZERO);
	lockinit(&ldep->de_lock, PINOD, "denode", 0, 0);
	nvp->v_data = ldep;
	ldep->de_vnode = nvp;
	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;
	fc_purge(ldep, 0);	/* init the fat cache for this denode */

	/*
	 * Insert the denode into the hash queue and lock the denode so it
	 * can't be accessed until we've read it in and have done what we
	 * need to it.
	 */
	vn_lock(nvp, LK_EXCLUSIVE | LK_RETRY, p);
	error = msdosfs_hashins(ldep);

	if (error) {
		vput (nvp);
		
		if (error == EEXIST)
			goto retry;

		return (error);
	}

	ldep->de_pmp = pmp;
	ldep->de_devvp = pmp->pm_devvp;
	ldep->de_refcnt = 1;
	/*
	 * Copy the directory entry into the denode area of the vnode.
	 */
	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.
		 */
	        nvp->v_flag |= VROOT; /* should be further down         XXX */

		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_CTime = 0x0000;	/* 00:00:00	 */
		ldep->de_CTimeHundredth = 0;
		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)
			return (error);
		DE_INTERNALIZE(ldep, direntptr);
		brelse(bp);
	}

	/*
	 * Fill in a few fields of the vnode 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.
		 */
		uint32_t size;

		nvp->v_type = VDIR;
		if (ldep->de_StartCluster != MSDOSFSROOT) {
			error = pcbmap(ldep, 0xffff, 0, &size, 0);
			if (error == E2BIG) {
				ldep->de_FileSize = de_cn2off(pmp, size);
				error = 0;
			} else if (error) {
				printf("deget(): pcbmap returned %d\n", error);
				return (error);
			}
		}
	} else
		nvp->v_type = VREG;
	vref(ldep->de_devvp);
	*depp = ldep;
	return (0);
}
/*
 * Be sure a directory is empty except for "." and "..". Return 1 if empty,
 * return 0 if not empty or error.
 */
int
dosdirempty(struct denode *dep)
{
	int blsize;
	int error;
	u_long cn;
	daddr_t bn;
	struct buf *bp;
	struct msdosfsmount *pmp = dep->de_pmp;
	struct direntry *dentp;

	/*
	 * Since the filesize field in directory entries for a directory is
	 * zero, we just have to feel our way through the directory until
	 * we hit end of file.
	 */
	for (cn = 0;; cn++) {
		if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
			if (error == E2BIG)
				return (1);	/* it's empty */
			return (0);
		}
		error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED,
		    0, &bp);
		if (error) {
			return (0);
		}
		for (dentp = (struct direntry *)bp->b_data;
		     (char *)dentp < (char *)bp->b_data + blsize;
		     dentp++) {
			if (dentp->deName[0] != SLOT_DELETED &&
			    (dentp->deAttributes & ATTR_VOLUME) == 0) {
				/*
				 * In dos directories an entry whose name
				 * starts with SLOT_EMPTY (0) starts the
				 * beginning of the unused part of the
				 * directory, so we can just return that it
				 * is empty.
				 */
				if (dentp->deName[0] == SLOT_EMPTY) {
					brelse(bp, 0);
					return (1);
				}
				/*
				 * Any names other than "." and ".." in a
				 * directory mean it is not empty.
				 */
				if (memcmp(dentp->deName, ".          ", 11) &&
				    memcmp(dentp->deName, "..         ", 11)) {
					brelse(bp, 0);
#ifdef MSDOSFS_DEBUG
					printf("dosdirempty(): found %.11s, %d, %d\n",
					    dentp->deName, dentp->deName[0],
						dentp->deName[1]);
#endif
					return (0);	/* not empty */
				}
			}
		}
		brelse(bp, 0);
	}
	/* NOTREACHED */
}
Exemple #17
0
/*
 * When we search a directory the blocks containing directory entries are
 * read and examined.  The directory entries contain information that would
 * normally be in the inode of a unix filesystem.  This means that some of
 * a directory's contents may also be in memory resident denodes (sort of
 * an inode).  This can cause problems if we are searching while some other
 * process is modifying a directory.  To prevent one process from accessing
 * incompletely modified directory information we depend upon being the
 * sole owner of a directory block.  bread/brelse provide this service.
 * This being the case, when a process modifies a directory it must first
 * acquire the disk block that contains the directory entry to be modified.
 * Then update the disk block and the denode, and then write the disk block
 * out to disk.  This way disk blocks containing directory entries and in
 * memory denode's will be in synch.
 */
static int
msdosfs_lookup_(struct vnode *vdp, struct vnode **vpp,
    struct componentname *cnp, u_int64_t *dd_inum)
{
	struct mbnambuf nb;
	daddr_t bn;
	int error;
	int slotcount;
	int slotoffset = 0;
	int frcn;
	u_long cluster;
	int blkoff;
	int diroff;
	int blsize;
	int isadir;		/* ~0 if found direntry is a directory	 */
	u_long scn;		/* starting cluster number		 */
	struct vnode *pdp;
	struct denode *dp;
	struct denode *tdp;
	struct msdosfsmount *pmp;
	struct buf *bp = 0;
	struct direntry *dep = NULL;
	u_char dosfilename[12];
	int flags = cnp->cn_flags;
	int nameiop = cnp->cn_nameiop;
	int unlen;
	u_int64_t inode1;

	int wincnt = 1;
	int chksum = -1, chksum_ok;
	int olddos = 1;

#ifdef MSDOSFS_DEBUG
	printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
#endif
	dp = VTODE(vdp);
	pmp = dp->de_pmp;
#ifdef MSDOSFS_DEBUG
	printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n",
	    vdp, dp, dp->de_Attributes);
#endif

 restart:
	if (vpp != NULL)
		*vpp = NULL;
	/*
	 * If they are going after the . or .. entry in the root directory,
	 * they won't find it.  DOS filesystems don't have them in the root
	 * directory.  So, we fake it. deget() is in on this scam too.
	 */
	if ((vdp->v_vflag & VV_ROOT) && cnp->cn_nameptr[0] == '.' &&
	    (cnp->cn_namelen == 1 ||
		(cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) {
		isadir = ATTR_DIRECTORY;
		scn = MSDOSFSROOT;
#ifdef MSDOSFS_DEBUG
		printf("msdosfs_lookup(): looking for . or .. in root directory\n");
#endif
		cluster = MSDOSFSROOT;
		blkoff = MSDOSFSROOT_OFS;
		goto foundroot;
	}

	switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename,
	    cnp->cn_namelen, 0, pmp)) {
	case 0:
		return (EINVAL);
	case 1:
		break;
	case 2:
		wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
		    cnp->cn_namelen, pmp) + 1;
		break;
	case 3:
		olddos = 0;
		wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr,
		    cnp->cn_namelen, pmp) + 1;
		break;
	}
	if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) {
		wincnt = 1;
		olddos = 1;
	}
	unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen);

	/*
	 * Suppress search for slots unless creating
	 * file and at end of pathname, in which case
	 * we watch for a place to put the new file in
	 * case it doesn't already exist.
	 */
	slotcount = wincnt;
	if ((nameiop == CREATE || nameiop == RENAME) &&
	    (flags & ISLASTCN))
		slotcount = 0;

#ifdef MSDOSFS_DEBUG
	printf("msdosfs_lookup(): dos version of filename %s, length %ld\n",
	    dosfilename, cnp->cn_namelen);
#endif
	/*
	 * Search the directory pointed at by vdp for the name pointed at
	 * by cnp->cn_nameptr.
	 */
	tdp = NULL;
	mbnambuf_init(&nb);
	/*
	 * The outer loop ranges over the clusters that make up the
	 * directory.  Note that the root directory is different from all
	 * other directories.  It has a fixed number of blocks that are not
	 * part of the pool of allocatable clusters.  So, we treat it a
	 * little differently. The root directory starts at "cluster" 0.
	 */
	diroff = 0;
	for (frcn = 0;; frcn++) {
		error = pcbmap(dp, frcn, &bn, &cluster, &blsize);
		if (error) {
			if (error == E2BIG)
				break;
			return (error);
		}
		error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
		if (error) {
			brelse(bp);
			return (error);
		}
		for (blkoff = 0; blkoff < blsize;
		     blkoff += sizeof(struct direntry),
		     diroff += sizeof(struct direntry)) {
			dep = (struct direntry *)(bp->b_data + blkoff);
			/*
			 * If the slot is empty and we are still looking
			 * for an empty then remember this one.  If the
			 * slot is not empty then check to see if it
			 * matches what we are looking for.  If the slot
			 * has never been filled with anything, then the
			 * remainder of the directory has never been used,
			 * so there is no point in searching it.
			 */
			if (dep->deName[0] == SLOT_EMPTY ||
			    dep->deName[0] == SLOT_DELETED) {
				/*
				 * Drop memory of previous long matches
				 */
				chksum = -1;
				mbnambuf_init(&nb);

				if (slotcount < wincnt) {
					slotcount++;
					slotoffset = diroff;
				}
				if (dep->deName[0] == SLOT_EMPTY) {
					brelse(bp);
					goto notfound;
				}
			} else {
				/*
				 * If there wasn't enough space for our winentries,
				 * forget about the empty space
				 */
				if (slotcount < wincnt)
					slotcount = 0;

				/*
				 * Check for Win95 long filename entry
				 */
				if (dep->deAttributes == ATTR_WIN95) {
					if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
						continue;

					chksum = win2unixfn(&nb,
					    (struct winentry *)dep, chksum,
					    pmp);
					continue;
				}

				chksum = winChkName(&nb,
				    (const u_char *)cnp->cn_nameptr, unlen,
				    chksum, pmp);
				if (chksum == -2) {
					chksum = -1;
					continue;
				}

				/*
				 * Ignore volume labels (anywhere, not just
				 * the root directory).
				 */
				if (dep->deAttributes & ATTR_VOLUME) {
					chksum = -1;
					continue;
				}

				/*
				 * Check for a checksum or name match
				 */
				chksum_ok = (chksum == winChksum(dep->deName));
				if (!chksum_ok
				    && (!olddos || bcmp(dosfilename, dep->deName, 11))) {
					chksum = -1;
					continue;
				}
#ifdef MSDOSFS_DEBUG
				printf("msdosfs_lookup(): match blkoff %d, diroff %d\n",
				    blkoff, diroff);
#endif
				/*
				 * Remember where this directory
				 * entry came from for whoever did
				 * this lookup.
				 */
				dp->de_fndoffset = diroff;
				if (chksum_ok && nameiop == RENAME) {
					/*
					 * Target had correct long name
					 * directory entries, reuse them
					 * as needed.
					 */
					dp->de_fndcnt = wincnt - 1;
				} else {
					/*
					 * Long name directory entries
					 * not present or corrupt, can only
					 * reuse dos directory entry.
					 */
					dp->de_fndcnt = 0;
				}

				goto found;
			}
		}	/* for (blkoff = 0; .... */
		/*
		 * Release the buffer holding the directory cluster just
		 * searched.
		 */
		brelse(bp);
	}	/* for (frcn = 0; ; frcn++) */

notfound:
	/*
	 * We hold no disk buffers at this point.
	 */

	/*
	 * Fixup the slot description to point to the place where
	 * we might put the new DOS direntry (putting the Win95
	 * long name entries before that)
	 */
	if (!slotcount) {
		slotcount = 1;
		slotoffset = diroff;
	}
	if (wincnt > slotcount)
		slotoffset += sizeof(struct direntry) * (wincnt - slotcount);

	/*
	 * If we get here we didn't find the entry we were looking for. But
	 * that's ok if we are creating or renaming and are at the end of
	 * the pathname and the directory hasn't been removed.
	 */
#ifdef MSDOSFS_DEBUG
	printf("msdosfs_lookup(): op %d, refcnt %ld\n",
	    nameiop, dp->de_refcnt);
	printf("               slotcount %d, slotoffset %d\n",
	       slotcount, slotoffset);
#endif
	if ((nameiop == CREATE || nameiop == RENAME) &&
	    (flags & ISLASTCN) && dp->de_refcnt != 0) {
		/*
		 * Access for write is interpreted as allowing
		 * creation of files in the directory.
		 */
		error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
		if (error)
			return (error);
		/*
		 * Return an indication of where the new directory
		 * entry should be put.
		 */
		dp->de_fndoffset = slotoffset;
		dp->de_fndcnt = wincnt - 1;

		/*
		 * 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;
		return (EJUSTRETURN);
	}
#if 0
	/*
	 * Insert name into cache (as non-existent) if appropriate.
	 *
	 * XXX Negative caching is broken for msdosfs because the name
	 * cache doesn't understand peculiarities such as case insensitivity
	 * and 8.3 filenames.  Hence, it may not invalidate all negative
	 * entries if a file with this name is later created.
	 */
	if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
		cache_enter(vdp, *vpp, cnp);
#endif
	return (ENOENT);

found:
	/*
	 * NOTE:  We still have the buffer with matched directory entry at
	 * this point.
	 */
	isadir = dep->deAttributes & ATTR_DIRECTORY;
	scn = getushort(dep->deStartCluster);
	if (FAT32(pmp)) {
		scn |= getushort(dep->deHighClust) << 16;
		if (scn == pmp->pm_rootdirblk) {
			/*
			 * There should actually be 0 here.
			 * Just ignore the error.
			 */
			scn = MSDOSFSROOT;
		}
	}

	if (isadir) {
		cluster = scn;
		if (cluster == MSDOSFSROOT)
			blkoff = MSDOSFSROOT_OFS;
		else
			blkoff = 0;
	} else if (cluster == MSDOSFSROOT)
		blkoff = diroff;

	/*
	 * Now release buf to allow deget to read the entry again.
	 * Reserving it here and giving it to deget could result
	 * in a deadlock.
	 */
	brelse(bp);
	bp = 0;
	
foundroot:
	/*
	 * If we entered at foundroot, then we are looking for the . or ..
	 * entry of the filesystems root directory.  isadir and scn were
	 * setup before jumping here.  And, bp is already null.
	 */
	if (FAT32(pmp) && scn == MSDOSFSROOT)
		scn = pmp->pm_rootdirblk;

	if (dd_inum != NULL) {
		*dd_inum = (uint64_t)pmp->pm_bpcluster * scn + blkoff;
		return (0);
	}

	/*
	 * If deleting, and at end of pathname, return
	 * parameters which can be used to remove file.
	 */
	if (nameiop == DELETE && (flags & ISLASTCN)) {
		/*
		 * Don't allow deleting the root.
		 */
		if (blkoff == MSDOSFSROOT_OFS)
			return (EBUSY);

		/*
		 * Write access to directory required to delete files.
		 */
		error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
		if (error)
			return (error);

		/*
		 * Return pointer to current entry in dp->i_offset.
		 * Save directory inode pointer in ndp->ni_dvp for dirremove().
		 */
		if (dp->de_StartCluster == scn && isadir) {	/* "." */
			VREF(vdp);
			*vpp = vdp;
			return (0);
		}
		error = deget(pmp, cluster, blkoff, &tdp);
		if (error)
			return (error);
		*vpp = DETOV(tdp);
		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 && (flags & ISLASTCN)) {
		if (blkoff == MSDOSFSROOT_OFS)
			return (EBUSY);

		error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread);
		if (error)
			return (error);

		/*
		 * Careful about locking second inode.
		 * This can only occur if the target is ".".
		 */
		if (dp->de_StartCluster == scn && isadir)
			return (EISDIR);

		if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
			return (error);
		*vpp = DETOV(tdp);
		cnp->cn_flags |= SAVENAME;
		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.
	 */
	pdp = vdp;
	if (flags & ISDOTDOT) {
		error = msdosfs_deget_dotdot(pdp, cluster, blkoff, vpp);
		if (error) {
			*vpp = NULL;
			return (error);
		}
		/*
		 * Recheck that ".." still points to the inode we
		 * looked up before pdp lock was dropped.
		 */
		error = msdosfs_lookup_(pdp, NULL, cnp, &inode1);
		if (error) {
			vput(*vpp);
			*vpp = NULL;
			return (error);
		}
		if (VTODE(*vpp)->de_inode != inode1) {
			vput(*vpp);
			goto restart;
		}
	} else if (dp->de_StartCluster == scn && isadir) {
		VREF(vdp);	/* we want ourself, ie "." */
		*vpp = vdp;
	} else {
		if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0)
			return (error);
		*vpp = DETOV(tdp);
	}

	/*
	 * Insert name into cache if appropriate.
	 */
	if (cnp->cn_flags & MAKEENTRY)
		cache_enter(vdp, *vpp, cnp);
	return (0);
}
/*
 * Remove a directory entry. At this point the file represented by the
 * directory entry to be removed is still full length until noone has it
 * open.  When the file no longer being used msdosfs_inactive() is called
 * and will truncate the file to 0 length.  When the vnode containing the
 * denode is needed for some other purpose by VFS it will call
 * msdosfs_reclaim() which will remove the denode from the denode cache.
 */
int
removede(struct denode *pdep, struct denode *dep)
	/* pdep:	 directory where the entry is removed */
	/* dep:	 file to be removed */
{
	int error;
	struct direntry *ep;
	struct buf *bp;
	daddr_t bn;
	int blsize;
	struct msdosfsmount *pmp = pdep->de_pmp;
	u_long offset = pdep->de_fndoffset;
#ifdef _KERNEL
	int async = pdep->de_pmp->pm_mountp->mnt_flag & MNT_ASYNC;
#else
#define async 0
#endif

#ifdef MSDOSFS_DEBUG
	printf("removede(): filename %s, dep %p, offset %08lx\n",
	    dep->de_Name, dep, offset);
#endif

	dep->de_refcnt--;
	offset += sizeof(struct direntry);
	do {
		offset -= sizeof(struct direntry);
		error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize);
		if (error)
			return error;
		error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED,
		    B_MODIFY, &bp);
		if (error) {
			return error;
		}
		ep = bptoep(pmp, bp, offset);
		/*
		 * Check whether, if we came here the second time, i.e.
		 * when underflowing into the previous block, the last
		 * entry in this block is a longfilename entry, too.
		 */
		if (ep->deAttributes != ATTR_WIN95
		    && offset != pdep->de_fndoffset) {
			brelse(bp, 0);
			break;
		}
		offset += sizeof(struct direntry);
		while (1) {
			/*
			 * We are a bit agressive here in that we delete any Win95
			 * entries preceding this entry, not just the ones we "own".
			 * Since these presumably aren't valid anyway,
			 * there should be no harm.
			 */
			offset -= sizeof(struct direntry);
			ep--->deName[0] = SLOT_DELETED;
			if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95)
			    || !(offset & pmp->pm_crbomask)
			    || ep->deAttributes != ATTR_WIN95)
				break;
		}
		if (async)
			bdwrite(bp);
		else if ((error = bwrite(bp)) != 0)
			return error;
	} while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95)
	    && !(offset & pmp->pm_crbomask)
	    && offset);
	return 0;
}
Exemple #19
0
/*
 * 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 buf *bp;
	daddr_t bn;
	int blsize;

#ifdef MSDOSFS_DEBUG
	kprintf("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
	    dep, ddep, depp, cnp);
#endif

	/*
	 * 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 = extendfile(ddep, dirclust, 0, 0, DE_CLEAR);
		if (error) {
			detrunc(ddep, ddep->de_FileSize, 0);
			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(pmp->pm_devvp, de_bntodoff(pmp, bn), blsize, &bp)) != 0) {
		brelse(bp);
		return error;
	}
	ndep = bptoep(pmp, bp, ddep->de_fndoffset);

	DE_EXTERNALIZE(ndep, dep);

	/*
	 * Now write the Win95 long name
	 */
	if (ddep->de_fndcnt > 0) {
		u_int8_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, NULL, &blsize);
				if (error)
					return error;

				error = bread(pmp->pm_devvp, de_bntodoff(pmp, bn), blsize, &bp);
				if (error) {
					brelse(bp);
					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,
					pmp))
				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, depp);
	}

	return 0;
}
Exemple #20
0
/*
 * If deget() succeeds it returns with the gotten denode locked().
 *
 * pmp	     - address of msdosfsmount structure of the filesystem containing
 *	       the denode of interest.  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)
{
	int error;
	uint64_t inode;
	struct mount *mntp = pmp->pm_mountp;
	struct direntry *direntptr;
	struct denode *ldep;
	struct vnode *nvp, *xvp;
	struct buf *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;

	/*
	 * See if the denode is in the denode cache. Use the location of
	 * the directory entry to compute the hash value. For subdir use
	 * address of "." entry. For root dir (if not FAT32) use cluster
	 * MSDOSFSROOT, offset MSDOSFSROOT_OFS
	 *
	 * NOTE: The check for de_refcnt > 0 below insures the denode being
	 * examined does not represent an unlinked but still open file.
	 * These files are not to be accessible even when the directory
	 * entry that represented the file happens to be reused while the
	 * deleted file is still open.
	 */
	inode = (uint64_t)pmp->pm_bpcluster * dirclust + diroffset;

	error = vfs_hash_get(mntp, inode, LK_EXCLUSIVE, curthread, &nvp,
	    de_vncmpf, &inode);
	if (error)
		return (error);
	if (nvp != NULL) {
		*depp = VTODE(nvp);
		KASSERT((*depp)->de_dirclust == dirclust, ("wrong dirclust"));
		KASSERT((*depp)->de_diroffset == diroffset, ("wrong diroffset"));
		return (0);
	}
	ldep = malloc(sizeof(struct denode), M_MSDOSFSNODE, M_WAITOK | M_ZERO);

	/*
	 * Directory entry was not in cache, have to create a vnode and
	 * copy it from the passed disk buffer.
	 */
	/* getnewvnode() does a VREF() on the vnode */
	error = getnewvnode("msdosfs", mntp, &msdosfs_vnodeops, &nvp);
	if (error) {
		*depp = NULL;
		free(ldep, M_MSDOSFSNODE);
		return error;
	}
	nvp->v_data = ldep;
	ldep->de_vnode = nvp;
	ldep->de_flag = 0;
	ldep->de_dirclust = dirclust;
	ldep->de_diroffset = diroffset;
	ldep->de_inode = inode;
	lockmgr(nvp->v_vnlock, LK_EXCLUSIVE, NULL);
	fc_purge(ldep, 0);	/* init the fat cache for this denode */
	error = insmntque(nvp, mntp);
	if (error != 0) {
		free(ldep, M_MSDOSFSNODE);
		*depp = NULL;
		return (error);
	}
	error = vfs_hash_insert(nvp, inode, LK_EXCLUSIVE, curthread, &xvp,
	    de_vncmpf, &inode);
	if (error) {
		*depp = NULL;
		return (error);
	}
	if (xvp != NULL) {
		*depp = xvp->v_data;
		return (0);
	}

	ldep->de_pmp = pmp;
	ldep->de_refcnt = 1;
	/*
	 * Copy the directory entry into the denode area of the vnode.
	 */
	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.
		 */
		nvp->v_vflag |= VV_ROOT; /* should be further down XXX */

		ldep->de_Attributes = ATTR_DIRECTORY;
		ldep->de_LowerCase = 0;
		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 * DEV_BSIZE;
		}
		/*
		 * fill in time and date so that fattime2timespec() 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) {
			/*
			 * The denode does not contain anything useful, so
			 * it would be wrong to leave it on its hash chain.
			 * Arrange for vput() to just forget about it.
			 */
			ldep->de_Name[0] = SLOT_DELETED;

			vput(nvp);
			*depp = NULL;
			return (error);
		}
		(void)DE_INTERNALIZE(ldep, direntptr);
		brelse(bp);
	}

	/*
	 * Fill in a few fields of the vnode 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;

		/*
		 * XXX it sometimes happens that the "." entry has cluster
		 * number 0 when it shouldn't.  Use the actual cluster number
		 * instead of what is written in directory entry.
		 */
		if (diroffset == 0 && ldep->de_StartCluster != dirclust) {
#ifdef MSDOSFS_DEBUG
			printf("deget(): \".\" entry at clust %lu != %lu\n",
			    dirclust, ldep->de_StartCluster);
#endif
			ldep->de_StartCluster = dirclust;
		}

		nvp->v_type = VDIR;
		if (ldep->de_StartCluster != MSDOSFSROOT) {
			error = pcbmap(ldep, 0xffff, 0, &size, 0);
			if (error == E2BIG) {
				ldep->de_FileSize = de_cn2off(pmp, size);
				error = 0;
			} else {
#ifdef MSDOSFS_DEBUG
				printf("deget(): pcbmap returned %d\n", error);
#endif
			}
		}
	} else
		nvp->v_type = VREG;
	ldep->de_modrev = init_va_filerev();
	*depp = ldep;
	return (0);
}
Exemple #21
0
int
msdosfs_readdir(void *v)
{
	struct vop_readdir_args *ap = v;
	int error = 0;
	int diff;
	long n;
	int blsize;
	long on;
	long lost;
	long count;
	uint32_t dirsperblk;
	uint32_t cn, lbn;
	uint32_t fileno;
	long bias = 0;
	daddr64_t bn;
	struct buf *bp;
	struct denode *dep = VTODE(ap->a_vp);
	struct msdosfsmount *pmp = dep->de_pmp;
	struct direntry *dentp;
	struct dirent dirbuf;
	struct uio *uio = ap->a_uio;
	u_long *cookies = NULL;
	int ncookies = 0;
	off_t offset, wlast = -1;
	int chksum = -1;

#ifdef MSDOSFS_DEBUG
	printf("msdosfs_readdir(): vp %08x, uio %08x, cred %08x, eofflagp %08x\n",
	    ap->a_vp, uio, ap->a_cred, ap->a_eofflag);
#endif

	/*
	 * msdosfs_readdir() won't operate properly on regular files since
	 * it does i/o only with the filesystem vnode, and hence can
	 * retrieve the wrong block from the buffer cache for a plain file.
	 * So, fail attempts to readdir() on a plain file.
	 */
	if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
		return (ENOTDIR);

	/*
	 * To be safe, initialize dirbuf
	 */
	bzero(dirbuf.d_name, sizeof(dirbuf.d_name));

	/*
	 * If the user buffer is smaller than the size of one dos directory
	 * entry or the file offset is not a multiple of the size of a
	 * directory entry, then we fail the read.
	 */
	count = uio->uio_resid & ~(sizeof(struct direntry) - 1);
	offset = uio->uio_offset;
	if (count < sizeof(struct direntry) ||
	    (offset & (sizeof(struct direntry) - 1)))
		return (EINVAL);
	lost = uio->uio_resid - count;
	uio->uio_resid = count;

	if (ap->a_ncookies) {
		ncookies = uio->uio_resid / sizeof(struct direntry) + 3;
		cookies = malloc(ncookies * sizeof(u_long), M_TEMP, M_WAITOK);
		*ap->a_cookies = cookies;
		*ap->a_ncookies = ncookies;
	}

	dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);

	/*
	 * If they are reading from the root directory then, we simulate
	 * the . and .. entries since these don't exist in the root
	 * directory.  We also set the offset bias to make up for having to
	 * simulate these entries. By this I mean that at file offset 64 we
	 * read the first entry in the root directory that lives on disk.
	 */
	if (dep->de_StartCluster == MSDOSFSROOT
	    || (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)) {
#if 0
		printf("msdosfs_readdir(): going after . or .. in root dir, offset %d\n",
		    offset);
#endif
		bias = 2 * sizeof(struct direntry);
		if (offset < bias) {
			for (n = (int)offset / sizeof(struct direntry);
			     n < 2; n++) {
			        if (FAT32(pmp))
				        dirbuf.d_fileno = pmp->pm_rootdirblk;
				else
				        dirbuf.d_fileno = 1;
				dirbuf.d_type = DT_DIR;
				switch (n) {
				case 0:
					dirbuf.d_namlen = 1;
					strlcpy(dirbuf.d_name, ".",
					    sizeof dirbuf.d_name);
					break;
				case 1:
					dirbuf.d_namlen = 2;
					strlcpy(dirbuf.d_name, "..",
					    sizeof dirbuf.d_name);
					break;
				}
				dirbuf.d_reclen = DIRENT_SIZE(&dirbuf);
				if (uio->uio_resid < dirbuf.d_reclen)
					goto out;
				error = uiomove((caddr_t) &dirbuf,
						dirbuf.d_reclen, uio);
				if (error)
					goto out;
				offset += sizeof(struct direntry);
				if (cookies) {
					*cookies++ = offset;
					if (--ncookies <= 0)
						goto out;
				}
			}
		}
	}

	while (uio->uio_resid > 0) {
		lbn = de_cluster(pmp, offset - bias);
		on = (offset - bias) & pmp->pm_crbomask;
		n = min(pmp->pm_bpcluster - on, uio->uio_resid);
		diff = dep->de_FileSize - (offset - bias);
		if (diff <= 0)
			break;
		n = min(n, diff);
		if ((error = pcbmap(dep, lbn, &bn, &cn, &blsize)) != 0)
			break;
		error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
		if (error) {
			brelse(bp);
			return (error);
		}
		n = min(n, blsize - bp->b_resid);

		/*
		 * Convert from dos directory entries to fs-independent
		 * directory entries.
		 */
		for (dentp = (struct direntry *)(bp->b_data + on);
		     (char *)dentp < bp->b_data + on + n;
		     dentp++, offset += sizeof(struct direntry)) {
#if 0
			printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
			    dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);
#endif
			/*
			 * If this is an unused entry, we can stop.
			 */
			if (dentp->deName[0] == SLOT_EMPTY) {
				brelse(bp);
				goto out;
			}
			/*
			 * Skip deleted entries.
			 */
			if (dentp->deName[0] == SLOT_DELETED) {
				chksum = -1;
				wlast = -1;
				continue;
			}

			/*
			 * Handle Win95 long directory entries
			 */
			if (dentp->deAttributes == ATTR_WIN95) {
				struct winentry *wep;
				if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
					continue;
				wep = (struct winentry *)dentp;
				chksum = win2unixfn(wep, &dirbuf, chksum);
				if (wep->weCnt & WIN_LAST)
					wlast = offset;
				continue;
			}

			/*
			 * Skip volume labels
			 */
			if (dentp->deAttributes & ATTR_VOLUME) {
				chksum = -1;
				wlast = -1;
				continue;
			}

			/*
			 * This computation of d_fileno must match
			 * the computation of va_fileid in
			 * msdosfs_getattr.
			 */
			fileno = getushort(dentp->deStartCluster);
			if (FAT32(pmp))
			    fileno |= getushort(dentp->deHighClust) << 16;

			if (dentp->deAttributes & ATTR_DIRECTORY) {
				/* Special-case root */
				if (fileno == MSDOSFSROOT)  {
					fileno = FAT32(pmp) ?
					    pmp->pm_rootdirblk : 1;
				}

				dirbuf.d_fileno = fileno;
				dirbuf.d_type = DT_DIR;
			} else {
				if (getulong(dentp->deFileSize) == 0) {
					uint64_t fileno64;

					fileno64 = (cn == MSDOSFSROOT) ?
					    roottobn(pmp, 0) : cntobn(pmp, cn);

					fileno64 *= dirsperblk;
					fileno64 += dentp -
					    (struct direntry *)bp->b_data;

					fileno = fileidhash(fileno64);
				}

				dirbuf.d_fileno = fileno;
				dirbuf.d_type = DT_REG;
			}

			if (chksum != winChksum(dentp->deName))
				dirbuf.d_namlen = dos2unixfn(dentp->deName,
				    (u_char *)dirbuf.d_name,
				    pmp->pm_flags & MSDOSFSMNT_SHORTNAME);
			else
				dirbuf.d_name[dirbuf.d_namlen] = 0;
			chksum = -1;
			dirbuf.d_reclen = DIRENT_SIZE(&dirbuf);
			if (uio->uio_resid < dirbuf.d_reclen) {
				brelse(bp);
				/* Remember long-name offset. */
				if (wlast != -1)
					offset = wlast;
				goto out;
			}
			wlast = -1;
			error = uiomove((caddr_t) &dirbuf,
					dirbuf.d_reclen, uio);
			if (error) {
				brelse(bp);
				goto out;
			}
			if (cookies) {
				*cookies++ = offset + sizeof(struct direntry);
				if (--ncookies <= 0) {
					brelse(bp);
					goto out;
				}
			}
		}
		brelse(bp);
	}

out:
	/* Subtract unused cookies */
	if (ap->a_ncookies)
		*ap->a_ncookies -= ncookies;

	uio->uio_offset = offset;
	uio->uio_resid += lost;
	if (dep->de_FileSize - (offset - bias) <= 0)
		*ap->a_eofflag = 1;
	else
		*ap->a_eofflag = 0;
	return (error);
}