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freebsd-skq/sys/fs/ext2fs/ext2_lookup.c
Pedro F. Giffuni 7cbd6d338e {ext2|ufs}_readdir: Avoid setting negative ncookies. 
ncookies cannot be negative or the allocator will fail. This should only
happen if a caller is very broken but we can still try to survive the
event.

We should probably also verify for uio_resid > MAXPHYS but in that case
it is not clear that just clipping the ncookies value is an adequate
response.

MFC after:	2 weeks
2018-02-06 22:38:19 +00:00

1243 lines
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/*-
* modified for Lites 1.1
*
* Aug 1995, Godmar Back (gback@cs.utah.edu)
* University of Utah, Department of Computer Science
*/
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
* @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/endian.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/dirent.h>
#include <sys/sysctl.h>
#include <ufs/ufs/dir.h>
#include <fs/ext2fs/inode.h>
#include <fs/ext2fs/ext2_mount.h>
#include <fs/ext2fs/ext2fs.h>
#include <fs/ext2fs/ext2_dinode.h>
#include <fs/ext2fs/ext2_dir.h>
#include <fs/ext2fs/ext2_extern.h>
#include <fs/ext2fs/fs.h>
#ifdef INVARIANTS
static int dirchk = 1;
#else
static int dirchk = 0;
#endif
static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD, 0, "EXT2FS filesystem");
SYSCTL_INT(_vfs_e2fs, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
/*
DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512)
while it is the native blocksize in ext2fs - thus, a #define
is no longer appropriate
*/
#undef DIRBLKSIZ
static u_char ext2_ft_to_dt[] = {
DT_UNKNOWN, /* EXT2_FT_UNKNOWN */
DT_REG, /* EXT2_FT_REG_FILE */
DT_DIR, /* EXT2_FT_DIR */
DT_CHR, /* EXT2_FT_CHRDEV */
DT_BLK, /* EXT2_FT_BLKDEV */
DT_FIFO, /* EXT2_FT_FIFO */
DT_SOCK, /* EXT2_FT_SOCK */
DT_LNK, /* EXT2_FT_SYMLINK */
};
#define FTTODT(ft) \
((ft) < nitems(ext2_ft_to_dt) ? ext2_ft_to_dt[(ft)] : DT_UNKNOWN)
static u_char dt_to_ext2_ft[] = {
EXT2_FT_UNKNOWN, /* DT_UNKNOWN */
EXT2_FT_FIFO, /* DT_FIFO */
EXT2_FT_CHRDEV, /* DT_CHR */
EXT2_FT_UNKNOWN, /* unused */
EXT2_FT_DIR, /* DT_DIR */
EXT2_FT_UNKNOWN, /* unused */
EXT2_FT_BLKDEV, /* DT_BLK */
EXT2_FT_UNKNOWN, /* unused */
EXT2_FT_REG_FILE, /* DT_REG */
EXT2_FT_UNKNOWN, /* unused */
EXT2_FT_SYMLINK, /* DT_LNK */
EXT2_FT_UNKNOWN, /* unused */
EXT2_FT_SOCK, /* DT_SOCK */
EXT2_FT_UNKNOWN, /* unused */
EXT2_FT_UNKNOWN, /* DT_WHT */
};
#define DTTOFT(dt) \
((dt) < nitems(dt_to_ext2_ft) ? dt_to_ext2_ft[(dt)] : EXT2_FT_UNKNOWN)
static int ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
int entryoffsetinblock);
static int ext2_is_dot_entry(struct componentname *cnp);
static int ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp,
struct componentname *cnp, ino_t *dd_ino);
static int
ext2_is_dot_entry(struct componentname *cnp)
{
if (cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' &&
(cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == '\0'))
return (1);
return (0);
}
/*
* Vnode op for reading directories.
*/
int
ext2_readdir(struct vop_readdir_args *ap)
{
struct vnode *vp = ap->a_vp;
struct uio *uio = ap->a_uio;
struct buf *bp;
struct inode *ip;
struct ext2fs_direct_2 *dp, *edp;
u_long *cookies;
struct dirent dstdp;
off_t offset, startoffset;
size_t readcnt, skipcnt;
ssize_t startresid;
u_int ncookies;
int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize;
int error;
if (uio->uio_offset < 0)
return (EINVAL);
ip = VTOI(vp);
if (ap->a_ncookies != NULL) {
if (uio->uio_resid < 0)
ncookies = 0;
else
ncookies = uio->uio_resid;
if (uio->uio_offset >= ip->i_size)
ncookies = 0;
else if (ip->i_size - uio->uio_offset < ncookies)
ncookies = ip->i_size - uio->uio_offset;
ncookies = ncookies / (offsetof(struct ext2fs_direct_2,
e2d_namlen) + 4) + 1;
cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK);
*ap->a_ncookies = ncookies;
*ap->a_cookies = cookies;
} else {
ncookies = 0;
cookies = NULL;
}
offset = startoffset = uio->uio_offset;
startresid = uio->uio_resid;
error = 0;
while (error == 0 && uio->uio_resid > 0 &&
uio->uio_offset < ip->i_size) {
error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp);
if (error)
break;
if (bp->b_offset + bp->b_bcount > ip->i_size)
readcnt = ip->i_size - bp->b_offset;
else
readcnt = bp->b_bcount;
skipcnt = (size_t)(uio->uio_offset - bp->b_offset) &
~(size_t)(DIRBLKSIZ - 1);
offset = bp->b_offset + skipcnt;
dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt];
edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt];
while (error == 0 && uio->uio_resid > 0 && dp < edp) {
if (dp->e2d_reclen <= offsetof(struct ext2fs_direct_2,
e2d_namlen) || (caddr_t)dp + dp->e2d_reclen >
(caddr_t)edp) {
error = EIO;
break;
}
/*-
* "New" ext2fs directory entries differ in 3 ways
* from ufs on-disk ones:
* - the name is not necessarily NUL-terminated.
* - the file type field always exists and always
* follows the name length field.
* - the file type is encoded in a different way.
*
* "Old" ext2fs directory entries need no special
* conversions, since they are binary compatible
* with "new" entries having a file type of 0 (i.e.,
* EXT2_FT_UNKNOWN). Splitting the old name length
* field didn't make a mess like it did in ufs,
* because ext2fs uses a machine-independent disk
* layout.
*/
dstdp.d_namlen = dp->e2d_namlen;
dstdp.d_type = FTTODT(dp->e2d_type);
if (offsetof(struct ext2fs_direct_2, e2d_namlen) +
dstdp.d_namlen > dp->e2d_reclen) {
error = EIO;
break;
}
if (offset < startoffset || dp->e2d_ino == 0)
goto nextentry;
dstdp.d_fileno = dp->e2d_ino;
dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp);
bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen);
dstdp.d_name[dstdp.d_namlen] = '\0';
if (dstdp.d_reclen > uio->uio_resid) {
if (uio->uio_resid == startresid)
error = EINVAL;
else
error = EJUSTRETURN;
break;
}
/* Advance dp. */
error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio);
if (error)
break;
if (cookies != NULL) {
KASSERT(ncookies > 0,
("ext2_readdir: cookies buffer too small"));
*cookies = offset + dp->e2d_reclen;
cookies++;
ncookies--;
}
nextentry:
offset += dp->e2d_reclen;
dp = (struct ext2fs_direct_2 *)((caddr_t)dp +
dp->e2d_reclen);
}
bqrelse(bp);
uio->uio_offset = offset;
}
/* We need to correct uio_offset. */
uio->uio_offset = offset;
if (error == EJUSTRETURN)
error = 0;
if (ap->a_ncookies != NULL) {
if (error == 0) {
ap->a_ncookies -= ncookies;
} else {
free(*ap->a_cookies, M_TEMP);
*ap->a_ncookies = 0;
*ap->a_cookies = NULL;
}
}
if (error == 0 && ap->a_eofflag)
*ap->a_eofflag = ip->i_size <= uio->uio_offset;
return (error);
}
/*
* Convert a component of a pathname into a pointer to a locked inode.
* This is a very central and rather complicated routine.
* If the file system is not maintained in a strict tree hierarchy,
* this can result in a deadlock situation (see comments in code below).
*
* The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
* on whether the name is to be looked up, created, renamed, or deleted.
* When CREATE, RENAME, or DELETE is specified, information usable in
* creating, renaming, or deleting a directory entry may be calculated.
* If flag has LOCKPARENT or'ed into it and the target of the pathname
* exists, lookup returns both the target and its parent directory locked.
* When creating or renaming and LOCKPARENT is specified, the target may
* not be ".". When deleting and LOCKPARENT is specified, the target may
* be "."., but the caller must check to ensure it does an vrele and vput
* instead of two vputs.
*
* Overall outline of ext2_lookup:
*
* search for name in directory, to found or notfound
* notfound:
* if creating, return locked directory, leaving info on available slots
* else return error
* found:
* if at end of path and deleting, return information to allow delete
* if at end of path and rewriting (RENAME and LOCKPARENT), lock target
* inode and return info to allow rewrite
* if not at end, add name to cache; if at end and neither creating
* nor deleting, add name to cache
*/
int
ext2_lookup(struct vop_cachedlookup_args *ap)
{
return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
}
static int
ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
ino_t *dd_ino)
{
struct inode *dp; /* inode for directory being searched */
struct buf *bp; /* a buffer of directory entries */
struct ext2fs_direct_2 *ep; /* the current directory entry */
int entryoffsetinblock; /* offset of ep in bp's buffer */
struct ext2fs_searchslot ss;
doff_t i_diroff; /* cached i_diroff value */
doff_t i_offset; /* cached i_offset value */
int numdirpasses; /* strategy for directory search */
doff_t endsearch; /* offset to end directory search */
doff_t prevoff; /* prev entry dp->i_offset */
struct vnode *pdp; /* saved dp during symlink work */
struct vnode *tdp; /* returned by VFS_VGET */
doff_t enduseful; /* pointer past last used dir slot */
u_long bmask; /* block offset mask */
int error;
struct ucred *cred = cnp->cn_cred;
int flags = cnp->cn_flags;
int nameiop = cnp->cn_nameiop;
ino_t ino, ino1;
int ltype;
int entry_found = 0;
int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize;
if (vpp != NULL)
*vpp = NULL;
dp = VTOI(vdp);
bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
restart:
bp = NULL;
ss.slotoffset = -1;
/*
* We now have a segment name to search for, and a directory to search.
*
* 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.
*/
i_diroff = dp->i_diroff;
ss.slotstatus = FOUND;
ss.slotfreespace = ss.slotsize = ss.slotneeded = 0;
if ((nameiop == CREATE || nameiop == RENAME) &&
(flags & ISLASTCN)) {
ss.slotstatus = NONE;
ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen);
/*
* was ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN +
* cnp->cn_namelen + 3) &~ 3;
*/
}
/*
* Try to lookup dir entry using htree directory index.
*
* If we got an error or we want to find '.' or '..' entry,
* we will fall back to linear search.
*/
if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) {
numdirpasses = 1;
entryoffsetinblock = 0;
switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
&bp, &entryoffsetinblock, &i_offset, &prevoff,
&enduseful, &ss)) {
case 0:
ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
(i_offset & bmask));
goto foundentry;
case ENOENT:
i_offset = roundup2(dp->i_size, DIRBLKSIZ);
goto notfound;
default:
/*
* Something failed; just fallback to do a linear
* search.
*/
break;
}
}
/*
* If there is cached information on a previous search of
* this directory, pick up where we last left off.
* We cache only lookups as these are the most common
* and have the greatest payoff. Caching CREATE has little
* benefit as it usually must search the entire directory
* to determine that the entry does not exist. Caching the
* location of the last DELETE or RENAME has not reduced
* profiling time and hence has been removed in the interest
* of simplicity.
*/
if (nameiop != LOOKUP || i_diroff == 0 ||
i_diroff > dp->i_size) {
entryoffsetinblock = 0;
i_offset = 0;
numdirpasses = 1;
} else {
i_offset = i_diroff;
if ((entryoffsetinblock = i_offset & bmask) &&
(error = ext2_blkatoff(vdp, (off_t)i_offset, NULL,
&bp)))
return (error);
numdirpasses = 2;
nchstats.ncs_2passes++;
}
prevoff = i_offset;
endsearch = roundup2(dp->i_size, DIRBLKSIZ);
enduseful = 0;
searchloop:
while (i_offset < endsearch) {
/*
* If necessary, get the next directory block.
*/
if (bp != NULL)
brelse(bp);
error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp);
if (error != 0)
return (error);
entryoffsetinblock = 0;
/*
* If still looking for a slot, and at a DIRBLKSIZE
* boundary, have to start looking for free space again.
*/
if (ss.slotstatus == NONE &&
(entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
ss.slotoffset = -1;
ss.slotfreespace = 0;
}
error = ext2_search_dirblock(dp, bp->b_data, &entry_found,
cnp->cn_nameptr, cnp->cn_namelen,
&entryoffsetinblock, &i_offset, &prevoff,
&enduseful, &ss);
if (error != 0) {
brelse(bp);
return (error);
}
if (entry_found) {
ep = (struct ext2fs_direct_2 *)((char *)bp->b_data +
(entryoffsetinblock & bmask));
foundentry:
ino = ep->e2d_ino;
goto found;
}
}
notfound:
/*
* If we started in the middle of the directory and failed
* to find our target, we must check the beginning as well.
*/
if (numdirpasses == 2) {
numdirpasses--;
i_offset = 0;
endsearch = i_diroff;
goto searchloop;
}
if (bp != NULL)
brelse(bp);
/*
* If creating, and at end of pathname and current
* directory has not been removed, then can consider
* allowing file to be created.
*/
if ((nameiop == CREATE || nameiop == RENAME) &&
(flags & ISLASTCN) && dp->i_nlink != 0) {
/*
* Access for write is interpreted as allowing
* creation of files in the directory.
*/
if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
return (error);
/*
* Return an indication of where the new directory
* entry should be put. If we didn't find a slot,
* then set dp->i_count to 0 indicating
* that the new slot belongs at the end of the
* directory. If we found a slot, then the new entry
* can be put in the range from dp->i_offset to
* dp->i_offset + dp->i_count.
*/
if (ss.slotstatus == NONE) {
dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
dp->i_count = 0;
enduseful = dp->i_offset;
} else {
dp->i_offset = ss.slotoffset;
dp->i_count = ss.slotsize;
if (enduseful < ss.slotoffset + ss.slotsize)
enduseful = ss.slotoffset + ss.slotsize;
}
dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
/*
* 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);
}
/*
* Insert name into cache (as non-existent) if appropriate.
*/
if ((cnp->cn_flags & MAKEENTRY) != 0)
cache_enter(vdp, NULL, cnp);
return (ENOENT);
found:
if (dd_ino != NULL)
*dd_ino = ino;
if (numdirpasses == 2)
nchstats.ncs_pass2++;
/*
* Check that directory length properly reflects presence
* of this entry.
*/
if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen)
> dp->i_size) {
ext2_dirbad(dp, i_offset, "i_size too small");
dp->i_size = entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
}
brelse(bp);
/*
* Found component in pathname.
* If the final component of path name, save information
* in the cache as to where the entry was found.
*/
if ((flags & ISLASTCN) && nameiop == LOOKUP)
dp->i_diroff = rounddown2(i_offset, DIRBLKSIZ);
/*
* If deleting, and at end of pathname, return
* parameters which can be used to remove file.
*/
if (nameiop == DELETE && (flags & ISLASTCN)) {
if (flags & LOCKPARENT)
ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
/*
* Write access to directory required to delete files.
*/
if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
return (error);
/*
* Return pointer to current entry in dp->i_offset,
* and distance past previous entry (if there
* is a previous entry in this block) in dp->i_count.
* Save directory inode pointer in ndp->ni_dvp for dirremove().
*
* Technically we shouldn't be setting these in the
* WANTPARENT case (first lookup in rename()), but any
* lookups that will result in directory changes will
* overwrite these.
*/
dp->i_offset = i_offset;
if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
dp->i_count = 0;
else
dp->i_count = dp->i_offset - prevoff;
if (dd_ino != NULL)
return (0);
if (dp->i_number == ino) {
VREF(vdp);
*vpp = vdp;
return (0);
}
if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
&tdp)) != 0)
return (error);
/*
* If directory is "sticky", then user must own
* the directory, or the file in it, else she
* may not delete it (unless she's root). This
* implements append-only directories.
*/
if ((dp->i_mode & ISVTX) &&
cred->cr_uid != 0 &&
cred->cr_uid != dp->i_uid &&
VTOI(tdp)->i_uid != cred->cr_uid) {
vput(tdp);
return (EPERM);
}
*vpp = 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 ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
return (error);
/*
* Careful about locking second inode.
* This can only occur if the target is ".".
*/
dp->i_offset = i_offset;
if (dp->i_number == ino)
return (EISDIR);
if (dd_ino != NULL)
return (0);
if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE,
&tdp)) != 0)
return (error);
*vpp = tdp;
cnp->cn_flags |= SAVENAME;
return (0);
}
if (dd_ino != NULL)
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) {
error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
if (pdp->v_iflag & VI_DOOMED) {
if (error == 0)
vput(tdp);
error = ENOENT;
}
if (error)
return (error);
/*
* Recheck that ".." entry in the vdp directory points
* to the inode we looked up before vdp lock was
* dropped.
*/
error = ext2_lookup_ino(pdp, NULL, cnp, &ino1);
if (error) {
vput(tdp);
return (error);
}
if (ino1 != ino) {
vput(tdp);
goto restart;
}
*vpp = tdp;
} else if (dp->i_number == ino) {
VREF(vdp); /* we want ourself, ie "." */
/*
* When we lookup "." we still can be asked to lock it
* differently.
*/
ltype = cnp->cn_lkflags & LK_TYPE_MASK;
if (ltype != VOP_ISLOCKED(vdp)) {
if (ltype == LK_EXCLUSIVE)
vn_lock(vdp, LK_UPGRADE | LK_RETRY);
else /* if (ltype == LK_SHARED) */
vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
}
*vpp = vdp;
} else {
if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags,
&tdp)) != 0)
return (error);
*vpp = tdp;
}
/*
* Insert name into cache if appropriate.
*/
if (cnp->cn_flags & MAKEENTRY)
cache_enter(vdp, *vpp, cnp);
return (0);
}
int
ext2_search_dirblock(struct inode *ip, void *data, int *foundp,
const char *name, int namelen, int *entryoffsetinblockp,
doff_t *offp, doff_t *prevoffp, doff_t *endusefulp,
struct ext2fs_searchslot *ssp)
{
struct vnode *vdp;
struct ext2fs_direct_2 *ep, *top;
uint32_t bsize = ip->i_e2fs->e2fs_bsize;
int offset = *entryoffsetinblockp;
int namlen;
vdp = ITOV(ip);
ep = (struct ext2fs_direct_2 *)((char *)data + offset);
top = (struct ext2fs_direct_2 *)((char *)data +
bsize - EXT2_DIR_REC_LEN(0));
while (ep < top) {
/*
* Full validation checks are slow, so we only check
* enough to insure forward progress through the
* directory. Complete checks can be run by setting
* "vfs.e2fs.dirchk" to be true.
*/
if (ep->e2d_reclen == 0 ||
(dirchk && ext2_dirbadentry(vdp, ep, offset))) {
int i;
ext2_dirbad(ip, *offp, "mangled entry");
i = bsize - (offset & (bsize - 1));
*offp += i;
offset += i;
continue;
}
/*
* If an appropriate sized slot has not yet been found,
* check to see if one is available. Also accumulate space
* in the current block so that we can determine if
* compaction is viable.
*/
if (ssp->slotstatus != FOUND) {
int size = ep->e2d_reclen;
if (ep->e2d_ino != 0)
size -= EXT2_DIR_REC_LEN(ep->e2d_namlen);
if (size > 0) {
if (size >= ssp->slotneeded) {
ssp->slotstatus = FOUND;
ssp->slotoffset = *offp;
ssp->slotsize = ep->e2d_reclen;
} else if (ssp->slotstatus == NONE) {
ssp->slotfreespace += size;
if (ssp->slotoffset == -1)
ssp->slotoffset = *offp;
if (ssp->slotfreespace >= ssp->slotneeded) {
ssp->slotstatus = COMPACT;
ssp->slotsize = *offp +
ep->e2d_reclen -
ssp->slotoffset;
}
}
}
}
/*
* Check for a name match.
*/
if (ep->e2d_ino) {
namlen = ep->e2d_namlen;
if (namlen == namelen &&
!bcmp(name, ep->e2d_name, (unsigned)namlen)) {
/*
* Save directory entry's inode number and
* reclen in ndp->ni_ufs area, and release
* directory buffer.
*/
*foundp = 1;
return (0);
}
}
*prevoffp = *offp;
*offp += ep->e2d_reclen;
offset += ep->e2d_reclen;
*entryoffsetinblockp = offset;
if (ep->e2d_ino)
*endusefulp = *offp;
/*
* Get pointer to the next entry.
*/
ep = (struct ext2fs_direct_2 *)((char *)data + offset);
}
return (0);
}
void
ext2_dirbad(struct inode *ip, doff_t offset, char *how)
{
struct mount *mp;
mp = ITOV(ip)->v_mount;
if ((mp->mnt_flag & MNT_RDONLY) == 0)
panic("ext2_dirbad: %s: bad dir ino %ju at offset %ld: %s\n",
mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
(long)offset, how);
else
(void)printf("%s: bad dir ino %ju at offset %ld: %s\n",
mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number,
(long)offset, how);
}
/*
* Do consistency checking on a directory entry:
* record length must be multiple of 4
* entry must fit in rest of its DIRBLKSIZ block
* record must be large enough to contain entry
* name is not longer than MAXNAMLEN
* name must be as long as advertised, and null terminated
*/
/*
* changed so that it confirms to ext2_check_dir_entry
*/
static int
ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de,
int entryoffsetinblock)
{
int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize;
char *error_msg = NULL;
if (de->e2d_reclen < EXT2_DIR_REC_LEN(1))
error_msg = "rec_len is smaller than minimal";
else if (de->e2d_reclen % 4 != 0)
error_msg = "rec_len % 4 != 0";
else if (de->e2d_reclen < EXT2_DIR_REC_LEN(de->e2d_namlen))
error_msg = "reclen is too small for name_len";
else if (entryoffsetinblock + de->e2d_reclen > DIRBLKSIZ)
error_msg = "directory entry across blocks";
/* else LATER
if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count)
error_msg = "inode out of bounds";
*/
if (error_msg != NULL) {
printf("bad directory entry: %s\n", error_msg);
printf("offset=%d, inode=%lu, rec_len=%u, name_len=%u\n",
entryoffsetinblock, (unsigned long)de->e2d_ino,
de->e2d_reclen, de->e2d_namlen);
}
return error_msg == NULL ? 0 : 1;
}
/*
* Write a directory entry after a call to namei, using the parameters
* that it left in nameidata. The argument ip is the inode which the new
* directory entry will refer to. Dvp is a pointer to the directory to
* be written, which was left locked by namei. Remaining parameters
* (dp->i_offset, dp->i_count) indicate how the space for the new
* entry is to be obtained.
*/
int
ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp)
{
struct inode *dp;
struct ext2fs_direct_2 newdir;
struct buf *bp;
int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize;
int error;
#ifdef INVARIANTS
if ((cnp->cn_flags & SAVENAME) == 0)
panic("ext2_direnter: missing name");
#endif
dp = VTOI(dvp);
newdir.e2d_ino = ip->i_number;
newdir.e2d_namlen = cnp->cn_namelen;
if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
EXT2F_INCOMPAT_FTYPE))
newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode));
else
newdir.e2d_type = EXT2_FT_UNKNOWN;
bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1);
if (ext2_htree_has_idx(dp)) {
error = ext2_htree_add_entry(dvp, &newdir, cnp);
if (error) {
dp->i_flag &= ~IN_E3INDEX;
dp->i_flag |= IN_CHANGE | IN_UPDATE;
}
return (error);
}
if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) &&
!ext2_htree_has_idx(dp)) {
if ((dp->i_size / DIRBLKSIZ) == 1 &&
dp->i_offset == DIRBLKSIZ) {
/*
* Making indexed directory when one block is not
* enough to save all entries.
*/
return ext2_htree_create_index(dvp, cnp, &newdir);
}
}
if (dp->i_count == 0) {
/*
* If dp->i_count is 0, then namei could find no
* space in the directory. Here, dp->i_offset will
* be on a directory block boundary and we will write the
* new entry into a fresh block.
*/
if (dp->i_offset & (DIRBLKSIZ - 1))
panic("ext2_direnter: newblk");
newdir.e2d_reclen = DIRBLKSIZ;
bp = getblk(ip->i_devvp, lblkno(dp->i_e2fs, dp->i_offset),
DIRBLKSIZ, 0, 0, 0);
if (!bp)
return (EIO);
memcpy(bp->b_data, &newdir, sizeof(struct ext2fs_direct_2));
ext2_dir_blk_csum_set(dp, bp);
error = bwrite(bp);
if (error)
return (error);
dp->i_size = roundup2(dp->i_size, DIRBLKSIZ);
dp->i_flag |= IN_CHANGE;
return (0);
}
error = ext2_add_entry(dvp, &newdir);
if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC,
cnp->cn_cred, cnp->cn_thread);
return (error);
}
/*
* Insert an entry into the directory block.
* Compact the contents.
*/
int
ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry)
{
struct ext2fs_direct_2 *ep, *nep;
struct inode *dp;
struct buf *bp;
u_int dsize;
int error, loc, newentrysize, spacefree;
char *dirbuf;
dp = VTOI(dvp);
/*
* If dp->i_count is non-zero, then namei found space
* for the new entry in the range dp->i_offset to
* dp->i_offset + dp->i_count in the directory.
* To use this space, we may have to compact the entries located
* there, by copying them together towards the beginning of the
* block, leaving the free space in one usable chunk at the end.
*/
/*
* Increase size of directory if entry eats into new space.
* This should never push the size past a new multiple of
* DIRBLKSIZE.
*
* N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
*/
if (dp->i_offset + dp->i_count > dp->i_size)
dp->i_size = dp->i_offset + dp->i_count;
/*
* Get the block containing the space for the new directory entry.
*/
if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf,
&bp)) != 0)
return (error);
/*
* Find space for the new entry. In the simple case, the entry at
* offset base will have the space. If it does not, then namei
* arranged that compacting the region dp->i_offset to
* dp->i_offset + dp->i_count would yield the
* space.
*/
newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen);
ep = (struct ext2fs_direct_2 *)dirbuf;
dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen);
spacefree = ep->e2d_reclen - dsize;
for (loc = ep->e2d_reclen; loc < dp->i_count; ) {
nep = (struct ext2fs_direct_2 *)(dirbuf + loc);
if (ep->e2d_ino) {
/* trim the existing slot */
ep->e2d_reclen = dsize;
ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
} else {
/* overwrite; nothing there; header is ours */
spacefree += dsize;
}
dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen);
spacefree += nep->e2d_reclen - dsize;
loc += nep->e2d_reclen;
bcopy((caddr_t)nep, (caddr_t)ep, dsize);
}
/*
* Update the pointer fields in the previous entry (if any),
* copy in the new entry, and write out the block.
*/
if (ep->e2d_ino == 0) {
if (spacefree + dsize < newentrysize)
panic("ext2_direnter: compact1");
entry->e2d_reclen = spacefree + dsize;
} else {
if (spacefree < newentrysize)
panic("ext2_direnter: compact2");
entry->e2d_reclen = spacefree;
ep->e2d_reclen = dsize;
ep = (struct ext2fs_direct_2 *)((char *)ep + dsize);
}
bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize);
ext2_dir_blk_csum_set(dp, bp);
if (DOINGASYNC(dvp)) {
bdwrite(bp);
error = 0;
} else {
error = bwrite(bp);
}
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Remove a directory entry after a call to namei, using
* the parameters which it left in nameidata. The entry
* dp->i_offset contains the offset into the directory of the
* entry to be eliminated. The dp->i_count field contains the
* size of the previous record in the directory. If this
* is 0, the first entry is being deleted, so we need only
* zero the inode number to mark the entry as free. If the
* entry is not the first in the directory, we must reclaim
* the space of the now empty record by adding the record size
* to the size of the previous entry.
*/
int
ext2_dirremove(struct vnode *dvp, struct componentname *cnp)
{
struct inode *dp;
struct ext2fs_direct_2 *ep, *rep;
struct buf *bp;
int error;
dp = VTOI(dvp);
if (dp->i_count == 0) {
/*
* First entry in block: set d_ino to zero.
*/
if ((error =
ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep,
&bp)) != 0)
return (error);
ep->e2d_ino = 0;
error = bwrite(bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Collapse new free space into previous entry.
*/
if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count),
(char **)&ep, &bp)) != 0)
return (error);
/* Set 'rep' to the entry being removed. */
if (dp->i_count == 0)
rep = ep;
else
rep = (struct ext2fs_direct_2 *)((char *)ep + ep->e2d_reclen);
ep->e2d_reclen += rep->e2d_reclen;
ext2_dir_blk_csum_set(dp, bp);
if (DOINGASYNC(dvp) && dp->i_count != 0)
bdwrite(bp);
else
error = bwrite(bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Rewrite an existing directory entry to point at the inode
* supplied. The parameters describing the directory entry are
* set up by a call to namei.
*/
int
ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp)
{
struct buf *bp;
struct ext2fs_direct_2 *ep;
struct vnode *vdp = ITOV(dp);
int error;
if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep,
&bp)) != 0)
return (error);
ep->e2d_ino = ip->i_number;
if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs,
EXT2F_INCOMPAT_FTYPE))
ep->e2d_type = DTTOFT(IFTODT(ip->i_mode));
else
ep->e2d_type = EXT2_FT_UNKNOWN;
ext2_dir_blk_csum_set(dp, bp);
error = bwrite(bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Check if a directory is empty or not.
* Inode supplied must be locked.
*
* Using a struct dirtemplate here is not precisely
* what we want, but better than using a struct direct.
*
* NB: does not handle corrupted directories.
*/
int
ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred)
{
off_t off;
struct dirtemplate dbuf;
struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf;
int error, namlen;
ssize_t count;
#define MINDIRSIZ (sizeof(struct dirtemplate) / 2)
for (off = 0; off < ip->i_size; off += dp->e2d_reclen) {
error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ,
off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred,
NOCRED, &count, (struct thread *)0);
/*
* Since we read MINDIRSIZ, residual must
* be 0 unless we're at end of file.
*/
if (error || count != 0)
return (0);
/* avoid infinite loops */
if (dp->e2d_reclen == 0)
return (0);
/* skip empty entries */
if (dp->e2d_ino == 0)
continue;
/* accept only "." and ".." */
namlen = dp->e2d_namlen;
if (namlen > 2)
return (0);
if (dp->e2d_name[0] != '.')
return (0);
/*
* At this point namlen must be 1 or 2.
* 1 implies ".", 2 implies ".." if second
* char is also "."
*/
if (namlen == 1)
continue;
if (dp->e2d_name[1] == '.' && dp->e2d_ino == parentino)
continue;
return (0);
}
return (1);
}
/*
* Check if source directory is in the path of the target directory.
* Target is supplied locked, source is unlocked.
* The target is always vput before returning.
*/
int
ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred)
{
struct vnode *vp;
int error, namlen;
struct dirtemplate dirbuf;
vp = ITOV(target);
if (target->i_number == source->i_number) {
error = EEXIST;
goto out;
}
if (target->i_number == EXT2_ROOTINO) {
error = 0;
goto out;
}
for (;;) {
if (vp->v_type != VDIR) {
error = ENOTDIR;
break;
}
error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE,
IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL,
NULL);
if (error != 0)
break;
namlen = dirbuf.dotdot_type; /* like ufs little-endian */
if (namlen != 2 ||
dirbuf.dotdot_name[0] != '.' ||
dirbuf.dotdot_name[1] != '.') {
error = ENOTDIR;
break;
}
if (dirbuf.dotdot_ino == source->i_number) {
error = EINVAL;
break;
}
if (dirbuf.dotdot_ino == EXT2_ROOTINO)
break;
vput(vp);
if ((error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino,
LK_EXCLUSIVE, &vp)) != 0) {
vp = NULL;
break;
}
}
out:
if (error == ENOTDIR)
printf("checkpath: .. not a directory\n");
if (vp != NULL)
vput(vp);
return (error);
}
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