ext2fs: Don't assume that on-disk format of a directory is the same
as in <sys/dirent.h> ext2_readdir() has always been very fs specific and different with respect to its ufs_ counterpart. Recent changes from UFS have made it possible to share more closely the implementation. MFUFS r252438: Always start parsing at DIRBLKSIZ aligned offset, skip first entries if uio_offset is not DIRBLKSIZ aligned. Return EINVAL if buffer is too small for single entry. Preallocate buffer for cookies. Skip entries with zero inode number. Reviewed by: gleb, Zheng Liu MFC after: 1 month
This commit is contained in:
Pedro F. Giffuni
parent
338b821b0f
commit
78d912bbc3
@ -128,33 +128,40 @@ ext2_is_dot_entry(struct componentname *cnp)
|
||||
|
||||
/*
|
||||
* Vnode op for reading directories.
|
||||
*
|
||||
* This function has to convert directory entries from the on-disk
|
||||
* format to the format defined by <sys/dirent.h>. Unfortunately, the
|
||||
* conversion will blow up some entries by four bytes, so it can't be
|
||||
* done in place. Instead, the conversion is done entry by entry and
|
||||
* the converted entry is sent via uiomove.
|
||||
*
|
||||
* XXX allocate a buffer, convert as many entries as possible, then send
|
||||
* the whole buffer to uiomove
|
||||
*/
|
||||
int
|
||||
ext2_readdir(struct vop_readdir_args *ap)
|
||||
{
|
||||
struct vnode *vp = ap->a_vp;
|
||||
struct uio *uio = ap->a_uio;
|
||||
int count, error;
|
||||
|
||||
struct ext2fs_direct_2 *edp, *dp;
|
||||
int ncookies;
|
||||
struct buf *bp;
|
||||
struct inode *ip;
|
||||
struct ext2fs_direct_2 *dp, *edp;
|
||||
u_long *cookies;
|
||||
struct dirent dstdp;
|
||||
struct uio auio;
|
||||
struct iovec aiov;
|
||||
caddr_t dirbuf;
|
||||
off_t offset, startoffset;
|
||||
size_t readcnt, skipcnt;
|
||||
ssize_t startresid;
|
||||
int ncookies;
|
||||
int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize;
|
||||
int readcnt;
|
||||
off_t startoffset = uio->uio_offset;
|
||||
int error;
|
||||
|
||||
count = uio->uio_resid;
|
||||
ip = VTOI(vp);
|
||||
if (ap->a_ncookies != NULL) {
|
||||
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;
|
||||
}
|
||||
/*
|
||||
* Avoid complications for partial directory entries by adjusting
|
||||
* the i/o to end at a block boundary. Don't give up (like ufs
|
||||
@ -163,25 +170,33 @@ ext2_readdir(struct vop_readdir_args *ap)
|
||||
* size is a little larger than DIRBLKSIZ to allow for expansion
|
||||
* of directory entries, but some callers just use 512.
|
||||
*/
|
||||
count -= (uio->uio_offset + count) & (DIRBLKSIZ -1);
|
||||
if (count <= 0)
|
||||
count += DIRBLKSIZ;
|
||||
auio = *uio;
|
||||
auio.uio_iov = &aiov;
|
||||
auio.uio_iovcnt = 1;
|
||||
auio.uio_resid = count;
|
||||
auio.uio_segflg = UIO_SYSSPACE;
|
||||
aiov.iov_len = count;
|
||||
dirbuf = malloc(count, M_TEMP, M_WAITOK);
|
||||
aiov.iov_base = dirbuf;
|
||||
error = VOP_READ(ap->a_vp, &auio, 0, ap->a_cred);
|
||||
if (error == 0) {
|
||||
readcnt = count - auio.uio_resid;
|
||||
edp = (struct ext2fs_direct_2 *)&dirbuf[readcnt];
|
||||
ncookies = 0;
|
||||
bzero(&dstdp, offsetof(struct dirent, d_name));
|
||||
for (dp = (struct ext2fs_direct_2 *)dirbuf;
|
||||
!error && uio->uio_resid > 0 && dp < edp; ) {
|
||||
if (uio->uio_offset < 0)
|
||||
offset = startoffset = uio->uio_offset + DIRBLKSIZ;
|
||||
else
|
||||
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:
|
||||
@ -198,57 +213,60 @@ ext2_readdir(struct vop_readdir_args *ap)
|
||||
* because ext2fs uses a machine-independent disk
|
||||
* layout.
|
||||
*/
|
||||
dstdp.d_fileno = dp->e2d_ino;
|
||||
dstdp.d_type = FTTODT(dp->e2d_type);
|
||||
dstdp.d_namlen = dp->e2d_namlen;
|
||||
dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp);
|
||||
bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen);
|
||||
bzero(dstdp.d_name + dstdp.d_namlen,
|
||||
dstdp.d_reclen - offsetof(struct dirent, d_name) -
|
||||
dstdp.d_namlen);
|
||||
|
||||
if (dp->e2d_reclen > 0) {
|
||||
if(dstdp.d_reclen <= uio->uio_resid) {
|
||||
/* advance dp */
|
||||
dp = (struct ext2fs_direct_2 *)
|
||||
((char *)dp + dp->e2d_reclen);
|
||||
error =
|
||||
uiomove(&dstdp, dstdp.d_reclen, uio);
|
||||
if (!error)
|
||||
ncookies++;
|
||||
} else
|
||||
break;
|
||||
} else {
|
||||
dstdp.d_type = FTTODT(dp->e2d_type);
|
||||
if (offsetof(struct ext2fs_direct_2, e2d_namlen) +
|
||||
dstdp.d_namlen > dp->e2d_reclen) {
|
||||
error = EIO;
|
||||
break;
|
||||
}
|
||||
}
|
||||
/* we need to correct uio_offset */
|
||||
uio->uio_offset = startoffset + (caddr_t)dp - dirbuf;
|
||||
|
||||
if (!error && ap->a_ncookies != NULL) {
|
||||
u_long *cookiep, *cookies, *ecookies;
|
||||
off_t off;
|
||||
|
||||
if (uio->uio_segflg != UIO_SYSSPACE || uio->uio_iovcnt != 1)
|
||||
panic("ext2_readdir: unexpected uio from NFS server");
|
||||
cookies = malloc(ncookies * sizeof(u_long), M_TEMP,
|
||||
M_WAITOK);
|
||||
off = startoffset;
|
||||
for (dp = (struct ext2fs_direct_2 *)dirbuf,
|
||||
cookiep = cookies, ecookies = cookies + ncookies;
|
||||
cookiep < ecookies;
|
||||
dp = (struct ext2fs_direct_2 *)((caddr_t) dp + dp->e2d_reclen)) {
|
||||
off += dp->e2d_reclen;
|
||||
*cookiep++ = (u_long) off;
|
||||
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;
|
||||
}
|
||||
*ap->a_ncookies = ncookies;
|
||||
*ap->a_cookies = cookies;
|
||||
/* 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;
|
||||
}
|
||||
}
|
||||
free(dirbuf, M_TEMP);
|
||||
if (ap->a_eofflag)
|
||||
*ap->a_eofflag = VTOI(ap->a_vp)->i_size <= uio->uio_offset;
|
||||
if (error == 0 && ap->a_eofflag)
|
||||
*ap->a_eofflag = ip->i_size <= uio->uio_offset;
|
||||
return (error);
|
||||
}
|
||||
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user