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/* $OpenBSD: msdosfs_lookup.c,v 1.16 2006/10/03 19:49:06 pedro Exp $ */
/* $NetBSD: msdosfs_lookup.c,v 1.34 1997/10/18 22:12:27 ws Exp $ */
/*-
* Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
* Copyright (C) 1994, 1995, 1997 TooLs GmbH.
* All rights reserved.
* Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by TooLs GmbH.
* 4. The name of TooLs GmbH may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Written by Paul Popelka (paulp@uts.amdahl.com)
*
* You can do anything you want with this software, just don't say you wrote
* it, and don't remove this notice.
*
* This software is provided "as is".
*
* The author supplies this software to be publicly redistributed on the
* understanding that the author is not responsible for the correct
* functioning of this software in any circumstances and is not liable for
* any damages caused by this software.
*
* October 1992
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/dirent.h>
#include <msdosfs/bpb.h>
#include <msdosfs/direntry.h>
#include <msdosfs/denode.h>
#include <msdosfs/msdosfsmount.h>
#include <msdosfs/fat.h>
/*
* 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(v)
void *v;
{
struct vop_lookup_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;
struct proc *p = cnp->cn_proc;
daddr64_t bn;
int error;
int lockparent;
int wantparent;
int slotcount;
int slotoffset = 0;
int frcn;
uint32_t cluster;
int blkoff;
int diroff;
int blsize;
int isadir; /* ~0 if found direntry is a directory */
uint32_t 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];
u_char *adjp;
int adjlen;
int flags;
int nameiop = cnp->cn_nameiop;
int wincnt = 1;
int chksum = -1, chksum_ok;
int olddos = 1;
cnp->cn_flags &= ~PDIRUNLOCK; /* XXX why this ?? */
flags = cnp->cn_flags;
#ifdef MSDOSFS_DEBUG
printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr);
#endif
dp = VTODE(vdp);
pmp = dp->de_pmp;
*vpp = NULL;
lockparent = flags & LOCKPARENT;
wantparent = flags & (LOCKPARENT | WANTPARENT);
#ifdef MSDOSFS_DEBUG
printf("msdosfs_lookup(): vdp %08x, dp %08x, Attr %02x\n",
vdp, dp, dp->de_Attributes);
#endif
/*
* Check accessiblity of directory.
*/
if ((dp->de_Attributes & ATTR_DIRECTORY) == 0)
return (ENOTDIR);
if ((error = VOP_ACCESS(vdp, VEXEC, cnp->cn_cred, cnp->cn_proc)) != 0)
return (error);
/*
* 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 ((error = cache_lookup(vdp, vpp, cnp)) >= 0)
return (error);
/*
* 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
printf("msdosfs_lookup(): looking for . or .. in root directory\n");
#endif
cluster = MSDOSFSROOT;
blkoff = MSDOSFSROOT_OFS;
goto foundroot;
}
switch (unix2dosfn((u_char *)cnp->cn_nameptr, dosfilename, cnp->cn_namelen, 0)) {
case 0:
return (EINVAL);
case 1:
break;
case 2:
wincnt = winSlotCnt((u_char *)cnp->cn_nameptr, cnp->cn_namelen) + 1;
break;
case 3:
olddos = 0;
wincnt = winSlotCnt((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 version of filename %s, length %d\n",
dosfilename, cnp->cn_namelen);
#endif
/*
* We want to search the directory pointed to by vdp for the name
* pointed to by cnp->cn_nameptr.
*
* XXX UNIX allows filenames with trailing dots and blanks; we don't.
* Most of the routines in msdosfs_conv.c adjust for this, but
* winChkName() does not, so we do it here. Otherwise, a file
* such as ".foobar." cannot be retrieved properly.
*
* (Note that this is also faster: perform the adjustment once,
* rather than on each call to winChkName. However, it is still
* a nasty hack.)
*/
adjp = cnp->cn_nameptr;
adjlen = cnp->cn_namelen;
for (adjp += adjlen; adjlen > 0; adjlen--)
if (*--adjp != ' ' && *adjp != '.')
break;
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;; frcn++) {
if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) {
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;
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 = winChkName((u_char *)cnp->cn_nameptr,
adjlen,
(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 || 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 %d\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_proc);
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;
if (!lockparent) {
VOP_UNLOCK(vdp, 0, p);
cnp->cn_flags |= PDIRUNLOCK;
}
return (EJUSTRETURN);
}
/*
* Insert name into cache (as non-existent) if appropriate.
*/
if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
cache_enter(vdp, *vpp, cnp);
return (ENOENT);
found:;
/*
* 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 (cluster == MSDOSFSROOT)
blkoff = diroff;
if (isadir) {
cluster = scn;
if (cluster == MSDOSFSROOT)
blkoff = MSDOSFSROOT_OFS;
else
blkoff = 0;
}
/*
* 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);
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 == DELETE && (flags & ISLASTCN)) {
/*
* Don't allow deleting the root.
*/
if (blkoff == MSDOSFSROOT_OFS)
return EROFS; /* really? XXX */
/*
* Write access to directory required to delete files.
*/
error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc);
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);
if (!lockparent) {
VOP_UNLOCK(vdp, 0, p);
cnp->cn_flags |= 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 == RENAME && wantparent &&
(flags & ISLASTCN)) {
if (blkoff == MSDOSFSROOT_OFS)
return EROFS; /* really? XXX */
error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc);
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;
if (!lockparent)
VOP_UNLOCK(vdp, 0, p);
return (0);
}
/*
* Step through the translation in the name. We do not `vput' the
* directory because we may need it again if a symbolic link
* is relative to the current directory. Instead we save it
* unlocked as "pdp". We must get the target inode before unlocking
* the directory to insure that the inode will not be removed
* before we get it. We prevent deadlock by always fetching
* inodes from the root, moving down the directory tree. Thus
* when following backward pointers ".." we must unlock the
* parent directory before getting the requested directory.
* There is a potential race condition here if both the current
* and parent directories are removed before the VFS_VGET for the
* inode associated with ".." returns. We hope that this occurs
* infrequently since we cannot avoid this race condition without
* implementing a sophisticated deadlock detection algorithm.
* Note also that this simple deadlock detection scheme will not
* work if the file system has any hard links other than ".."
* that point backwards in the directory structure.
*/
pdp = vdp;
if (flags & ISDOTDOT) {
VOP_UNLOCK(pdp, 0, p); /* race to get the inode */
cnp->cn_flags |= PDIRUNLOCK;
if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) {
if (vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p) == 0)
cnp->cn_flags &= ~PDIRUNLOCK;
return (error);
}
if (lockparent && (flags & ISLASTCN)) {
if ((error = vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY,
p))) {
vput(DETOV(tdp));
return (error);
}
cnp->cn_flags &= ~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 || !(flags & ISLASTCN)) {
VOP_UNLOCK(pdp, 0, p);
cnp->cn_flags |= PDIRUNLOCK;
}
*vpp = DETOV(tdp);
}
/*
* Insert name into cache if appropriate.
*/
if (cnp->cn_flags & MAKEENTRY)
cache_enter(vdp, *vpp, cnp);
return (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(dep, ddep, depp, cnp)
struct denode *dep;
struct denode *ddep;
struct denode **depp;
struct componentname *cnp;
{
int error;
uint32_t dirclust, diroffset;
struct direntry *ndep;
struct msdosfsmount *pmp = ddep->de_pmp;
struct buf *bp;
daddr64_t bn;
int blsize;
#ifdef MSDOSFS_DEBUG
printf("createde(dep %08x, ddep %08x, depp %08x, cnp %08x)\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);
if ((error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR)) != 0) {
(void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL);
return error;
}
/*
* Update the size of the directory
*/
ddep->de_FileSize += de_cn2off(pmp, dirclust);
}
/*
* We just read in the cluster with space. Copy the new directory
* entry in. Then write it to disk. NOTE: DOS directories
* do not get smaller as clusters are emptied.
*/
error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset),
&bn, &dirclust, &blsize);
if (error)
return error;
diroffset = ddep->de_fndoffset;
if (dirclust != MSDOSFSROOT)
diroffset &= pmp->pm_crbomask;
if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &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);
u_char *un = (u_char *)cnp->cn_nameptr;
int unlen = cnp->cn_namelen;
int cnt = 1;
while (--ddep->de_fndcnt >= 0) {
if (!(ddep->de_fndoffset & pmp->pm_crbomask)) {
if ((error = bwrite(bp)) != 0)
return error;
ddep->de_fndoffset -= sizeof(struct direntry);
error = pcbmap(ddep,
de_cluster(pmp,
ddep->de_fndoffset),
&bn, 0, &blsize);
if (error)
return error;
error = bread(pmp->pm_devvp, bn, blsize,
NOCRED, &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))
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;
}
/*
* Be sure a directory is empty except for "." and "..". Return 1 if empty,
* return 0 if not empty or error.
*/
int
dosdirempty(dep)
struct denode *dep;
{
int blsize;
int error;
uint32_t cn;
daddr64_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, bn, blsize, NOCRED, &bp);
if (error) {
brelse(bp);
return (0);
}
for (dentp = (struct direntry *)bp->b_data;
(char *)dentp < 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);
return (1);
}
/*
* Any names other than "." and ".." in a
* directory mean it is not empty.
*/
if (bcmp(dentp->deName, ". ", 11) &&
bcmp(dentp->deName, ".. ", 11)) {
brelse(bp);
#ifdef MSDOSFS_DEBUG
printf("dosdirempty(): entry found %02x, %02x\n",
dentp->deName[0], dentp->deName[1]);
#endif
return (0); /* not empty */
}
}
}
brelse(bp);
}
/* NOTREACHED */
}
/*
* Check to see if the directory described by target is in some
* subdirectory of source. This prevents something like the following from
* succeeding and leaving a bunch or files and directories orphaned. mv
* /a/b/c /a/b/c/d/e/f Where c and f are directories.
*
* source - the inode for /a/b/c
* target - the inode for /a/b/c/d/e/f
*
* Returns 0 if target is NOT a subdirectory of source.
* Otherwise returns a non-zero error number.
* The target inode is always unlocked on return.
*/
int
doscheckpath(source, target)
struct denode *source;
struct denode *target;
{
daddr_t scn;
struct msdosfsmount *pmp;
struct direntry *ep;
struct denode *dep;
struct buf *bp = NULL;
int error = 0;
dep = target;
if ((target->de_Attributes & ATTR_DIRECTORY) == 0 ||
(source->de_Attributes & ATTR_DIRECTORY) == 0) {
error = ENOTDIR;
goto out;
}
if (dep->de_StartCluster == source->de_StartCluster) {
error = EEXIST;
goto out;
}
if (dep->de_StartCluster == MSDOSFSROOT)
goto out;
pmp = dep->de_pmp;
#ifdef DIAGNOSTIC
if (pmp != source->de_pmp)
panic("doscheckpath: source and target on different filesystems");
#endif
if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)
goto out;
for (;;) {
if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) {
error = ENOTDIR;
break;
}
scn = dep->de_StartCluster;
error = bread(pmp->pm_devvp, cntobn(pmp, scn),
pmp->pm_bpcluster, NOCRED, &bp);
if (error)
break;
ep = (struct direntry *) bp->b_data + 1;
if ((ep->deAttributes & ATTR_DIRECTORY) == 0 ||
bcmp(ep->deName, ".. ", 11) != 0) {
error = ENOTDIR;
break;
}
scn = getushort(ep->deStartCluster);
if (FAT32(pmp))
scn |= getushort(ep->deHighClust) << 16;
if (scn == source->de_StartCluster) {
error = EINVAL;
break;
}
if (scn == MSDOSFSROOT)
break;
if (FAT32(pmp) && scn == pmp->pm_rootdirblk) {
/*
* scn should be 0 in this case,
* but we silently ignore the error.
*/
break;
}
vput(DETOV(dep));
brelse(bp);
bp = NULL;
/* NOTE: deget() clears dep on error */
if ((error = deget(pmp, scn, 0, &dep)) != 0)
break;
}
out:;
if (bp)
brelse(bp);
if (error == ENOTDIR)
printf("doscheckpath(): .. not a directory?\n");
if (dep != NULL)
vput(DETOV(dep));
return (error);
}
/*
* Read in the disk block containing the directory entry (dirclu, dirofs)
* and return the address of the buf header, and the address of the
* directory entry within the block.
*/
int
readep(pmp, dirclust, diroffset, bpp, epp)
struct msdosfsmount *pmp;
uint32_t dirclust, diroffset;
struct buf **bpp;
struct direntry **epp;
{
int error;
daddr_t bn;
int blsize;
uint32_t boff;
boff = diroffset & ~pmp->pm_crbomask;
blsize = pmp->pm_bpcluster;
if (dirclust == MSDOSFSROOT
&& de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
bn = detobn(pmp, dirclust, diroffset);
if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) {
brelse(*bpp);
*bpp = NULL;
return (error);
}
if (epp)
*epp = bptoep(pmp, *bpp, diroffset);
return (0);
}
/*
* Read in the disk block containing the directory entry dep came from and
* return the address of the buf header, and the address of the directory
* entry within the block.
*/
int
readde(dep, bpp, epp)
struct denode *dep;
struct buf **bpp;
struct direntry **epp;
{
return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
bpp, epp));
}
/*
* 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(pdep, dep)
struct denode *pdep; /* directory where the entry is removed */
struct denode *dep; /* file to be removed */
{
int error;
struct direntry *ep;
struct buf *bp;
daddr64_t bn;
int blsize;
struct msdosfsmount *pmp = pdep->de_pmp;
uint32_t offset = pdep->de_fndoffset;
#ifdef MSDOSFS_DEBUG
printf("removede(): filename %s, dep %08x, offset %08x\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, bn, blsize, NOCRED, &bp);
if (error) {
brelse(bp);
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);
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 ((error = bwrite(bp)) != 0)
return error;
} while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95)
&& !(offset & pmp->pm_crbomask)
&& offset);
return 0;
}
/*
* Create a unique DOS name in dvp
*/
int
uniqdosname(dep, cnp, cp)
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;
daddr64_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, NOCRED, &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(dep)
struct denode *dep;
{
struct msdosfsmount *pmp = dep->de_pmp;
struct direntry *dentp;
int blsize;
uint32_t cn;
daddr64_t bn;
struct buf *bp;
/*
* Read through the directory looking for Win'95 entries
* Note: Error currently handled just as EOF XXX
*/
for (cn = 0;; cn++) {
if (pcbmap(dep, cn, &bn, 0, &blsize))
return 0;
if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) {
brelse(bp);
return 0;
}
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;
}
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);
return 1;
}
}
brelse(bp);
}
}
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