/*
* 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;
}
/*
* 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);
}
/*
* 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;
}
/*
* 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);
}