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[unix-history] / usr / src / sys / ufs / ffs / ufs_lookup.c
/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* @(#)ufs_lookup.c 7.7 (Berkeley) %G%
*/
#include "param.h"
#include "user.h"
#include "buf.h"
#include "file.h"
#include "vnode.h"
#include "../ufs/inode.h"
#include "../ufs/fs.h"
struct vnode *cache_lookup();
struct nchstats nchstats;
int dirchk = 1;
/*
* 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 flag 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 iput
* instead of two iputs.
*
* Overall outline of ufs_lookup:
*
* check accessibility of directory
* look for name in cache, if found, then if at end of path
* and deleting or creating, drop it, else return name
* 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
*
* NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked.
*/
ufs_lookup(vp, ndp)
struct vnode *vp;
register struct nameidata *ndp;
{
register struct vnode *vdp; /* vnode copy of dp */
register struct inode *dp = 0; /* the directory we are searching */
register struct fs *fs; /* file system that directory is in */
struct buf *bp = 0; /* a buffer of directory entries */
register struct direct *ep; /* the current directory entry */
int entryoffsetinblock; /* offset of ep in bp's buffer */
enum {NONE, COMPACT, FOUND} slotstatus;
int slotoffset = -1; /* offset of area with free space */
int slotsize; /* size of area at slotoffset */
int slotfreespace; /* amount of space free in slot */
int slotneeded; /* size of the entry we're seeking */
int numdirpasses; /* strategy for directory search */
int endsearch; /* offset to end directory search */
int prevoff; /* ndp->ni_offset of previous entry */
struct inode *pdp; /* saved dp during symlink work */
struct inode *tdp; /* returned by iget */
off_t enduseful; /* pointer past last used dir slot */
int flag; /* LOOKUP, CREATE, RENAME, or DELETE */
int lockparent; /* 1 => lockparent flag is set */
int wantparent; /* 1 => wantparent or lockparent flag */
int error;
ndp->ni_dvp = vp;
ndp->ni_vp = NULL;
dp = VTOI(vp);
fs = dp->i_fs;
lockparent = ndp->ni_nameiop & LOCKPARENT;
flag = ndp->ni_nameiop & OPFLAG;
wantparent = ndp->ni_nameiop & (LOCKPARENT|WANTPARENT);
/*
* Check accessiblity of directory.
*/
if ((dp->i_mode&IFMT) != IFDIR)
return (ENOTDIR);
if (error = iaccess(dp, IEXEC, ndp->ni_cred))
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 (vdp = cache_lookup(ndp)) {
/*
* Get the next vnode in the path.
* See comment above `IUNLOCK' code for
* an explaination of the locking protocol.
*/
pdp = dp;
dp = VTOI(vdp);
if (pdp == dp) {
vdp->v_count++;
} else if (ndp->ni_isdotdot) {
IUNLOCK(pdp);
igrab(dp);
} else {
igrab(dp);
IUNLOCK(pdp);
}
ndp->ni_vp = vdp;
return (0);
}
/*
* 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.
*/
slotstatus = FOUND;
if ((flag == CREATE || flag == RENAME) && *ndp->ni_next == 0) {
slotstatus = NONE;
slotfreespace = 0;
slotneeded = DIRSIZ(&ndp->ni_dent);
}
/*
* 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 (flag != LOOKUP || dp->i_diroff == 0 || dp->i_diroff > dp->i_size) {
ndp->ni_offset = 0;
numdirpasses = 1;
} else {
ndp->ni_offset = dp->i_diroff;
entryoffsetinblock = blkoff(fs, ndp->ni_offset);
if (entryoffsetinblock != 0) {
error = blkatoff(dp, ndp->ni_offset, (char **)0, &bp);
if (error)
return (error);
}
numdirpasses = 2;
nchstats.ncs_2passes++;
}
endsearch = roundup(dp->i_size, DIRBLKSIZ);
enduseful = 0;
searchloop:
while (ndp->ni_offset < endsearch) {
/*
* If offset is on a block boundary,
* read the next directory block.
* Release previous if it exists.
*/
if (blkoff(fs, ndp->ni_offset) == 0) {
if (bp != NULL)
brelse(bp);
error = blkatoff(dp, ndp->ni_offset, (char **)0, &bp);
if (error)
return (error);
entryoffsetinblock = 0;
}
/*
* If still looking for a slot, and at a DIRBLKSIZE
* boundary, have to start looking for free space again.
*/
if (slotstatus == NONE &&
(entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) {
slotoffset = -1;
slotfreespace = 0;
}
/*
* Get pointer to next entry.
* Full validation checks are slow, so we only check
* enough to insure forward progress through the
* directory. Complete checks can be run by patching
* "dirchk" to be true.
*/
ep = (struct direct *)(bp->b_un.b_addr + entryoffsetinblock);
if (ep->d_reclen == 0 ||
dirchk && dirbadentry(ep, entryoffsetinblock)) {
int i;
dirbad(dp, ndp->ni_offset, "mangled entry");
i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
ndp->ni_offset += i;
entryoffsetinblock += 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 (slotstatus != FOUND) {
int size = ep->d_reclen;
if (ep->d_ino != 0)
size -= DIRSIZ(ep);
if (size > 0) {
if (size >= slotneeded) {
slotstatus = FOUND;
slotoffset = ndp->ni_offset;
slotsize = ep->d_reclen;
} else if (slotstatus == NONE) {
slotfreespace += size;
if (slotoffset == -1)
slotoffset = ndp->ni_offset;
if (slotfreespace >= slotneeded) {
slotstatus = COMPACT;
slotsize = ndp->ni_offset +
ep->d_reclen - slotoffset;
}
}
}
}
/*
* Check for a name match.
*/
if (ep->d_ino) {
if (ep->d_namlen == ndp->ni_dent.d_namlen &&
!bcmp(ndp->ni_ptr, ep->d_name,
(unsigned)ep->d_namlen)) {
/*
* Save directory entry's inode number and
* reclen in ndp->ni_dent, and release
* directory buffer.
*/
ndp->ni_dent.d_ino = ep->d_ino;
ndp->ni_dent.d_reclen = ep->d_reclen;
brelse(bp);
goto found;
}
}
prevoff = ndp->ni_offset;
ndp->ni_offset += ep->d_reclen;
entryoffsetinblock += ep->d_reclen;
if (ep->d_ino)
enduseful = ndp->ni_offset;
}
/* 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--;
ndp->ni_offset = 0;
endsearch = dp->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 ((flag == CREATE || flag == RENAME) &&
*ndp->ni_next == 0 && dp->i_nlink != 0) {
/*
* Access for write is interpreted as allowing
* creation of files in the directory.
*/
if (error = iaccess(dp, IWRITE, ndp->ni_cred))
return (error);
/*
* Return an indication of where the new directory
* entry should be put. If we didn't find a slot,
* then set ndp->ni_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
* [ndp->ni_offset .. ndp->ni_offset + ndp->ni_count)
*/
if (slotstatus == NONE) {
ndp->ni_offset = roundup(dp->i_size, DIRBLKSIZ);
ndp->ni_count = 0;
enduseful = ndp->ni_offset;
} else {
ndp->ni_offset = slotoffset;
ndp->ni_count = slotsize;
if (enduseful < slotoffset + slotsize)
enduseful = slotoffset + slotsize;
}
ndp->ni_endoff = roundup(enduseful, DIRBLKSIZ);
dp->i_flag |= IUPD|ICHG;
/*
* 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.
*/
if (!lockparent)
IUNLOCK(dp);
}
return (ENOENT);
found:
if (numdirpasses == 2)
nchstats.ncs_pass2++;
/*
* Check that directory length properly reflects presence
* of this entry.
*/
if (entryoffsetinblock + DIRSIZ(ep) > dp->i_size) {
dirbad(dp, ndp->ni_offset, "i_size too small");
dp->i_size = entryoffsetinblock + DIRSIZ(ep);
dp->i_flag |= IUPD|ICHG;
}
/*
* Found component in pathname.
* If the final component of path name, save information
* in the cache as to where the entry was found.
*/
if (*ndp->ni_next == '\0' && flag == LOOKUP)
dp->i_diroff = ndp->ni_offset &~ (DIRBLKSIZ - 1);
/*
* 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 (flag == DELETE && *ndp->ni_next == 0) {
/*
* Write access to directory required to delete files.
*/
if (error = iaccess(dp, IWRITE, ndp->ni_cred))
return (error);
/*
* Return pointer to current entry in ndp->ni_offset,
* and distance past previous entry (if there
* is a previous entry in this block) in ndp->ni_count.
* Save directory inode pointer in ndp->ni_pdir for dirremove().
*/
if ((ndp->ni_offset&(DIRBLKSIZ-1)) == 0)
ndp->ni_count = 0;
else
ndp->ni_count = ndp->ni_offset - prevoff;
vdp = ITOV(dp);
if (dp->i_number == ndp->ni_dent.d_ino) {
vdp->v_count++;
} else {
pdp = dp;
if (error = iget(dp, ndp->ni_dent.d_ino, &tdp))
return (error);
vdp = ITOV(tdp);
/*
* If directory is "sticky", then user must own
* the directory, or the file in it, else he
* may not delete it (unless he's root). This
* implements append-only directories.
*/
if ((pdp->i_mode & ISVTX) &&
ndp->ni_cred->cr_uid != 0 &&
ndp->ni_cred->cr_uid != pdp->i_uid &&
tdp->i_uid != ndp->ni_cred->cr_uid) {
iput(tdp);
return (EPERM);
}
}
ndp->ni_vp = vdp;
if (!lockparent)
IUNLOCK(pdp);
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 (flag == RENAME && wantparent && *ndp->ni_next == 0) {
if (error = iaccess(dp, IWRITE, ndp->ni_cred))
return (error);
/*
* Careful about locking second inode.
* This can only occur if the target is ".".
*/
if (dp->i_number == ndp->ni_dent.d_ino)
return (EISDIR);
if (error = iget(dp, ndp->ni_dent.d_ino, &tdp))
return (error);
ndp->ni_vp = ITOV(tdp);
if (!lockparent)
IUNLOCK(dp);
return (0);
}
/*
* Step through the translation in the name. We do not `iput' 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 `iget' 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 = dp;
if (ndp->ni_isdotdot) {
IUNLOCK(pdp); /* race to get the inode */
if (error = iget(dp, ndp->ni_dent.d_ino, &tdp)) {
ILOCK(pdp);
return (error);
}
ndp->ni_vp = ITOV(tdp);
} else if (dp->i_number == ndp->ni_dent.d_ino) {
vdp = ITOV(dp);
vdp->v_count++; /* we want ourself, ie "." */
ndp->ni_vp = vdp;
} else {
if (error = iget(dp, ndp->ni_dent.d_ino, &tdp))
return (error);
IUNLOCK(pdp);
ndp->ni_vp = ITOV(tdp);
}
/*
* Insert name into cache if appropriate.
*/
if (ndp->ni_makeentry)
cache_enter(ndp);
return (0);
}
dirbad(ip, offset, how)
struct inode *ip;
off_t offset;
char *how;
{
printf("%s: bad dir ino %d at offset %d: %s\n",
ip->i_fs->fs_fsmnt, ip->i_number, 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
*/
dirbadentry(ep, entryoffsetinblock)
register struct direct *ep;
int entryoffsetinblock;
{
register int i;
if ((ep->d_reclen & 0x3) != 0 ||
ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
ep->d_reclen < DIRSIZ(ep) || ep->d_namlen > MAXNAMLEN)
return (1);
for (i = 0; i < ep->d_namlen; i++)
if (ep->d_name[i] == '\0')
return (1);
return (ep->d_name[i]);
}
/*
* Write a directory entry after a call to namei, using the parameters
* which it left in nameidata. The argument ip is the inode which the
* new directory entry will refer to. The nameidata field ndp->ni_dvp
* is a pointer to the directory to be written, which was left locked by
* namei. Remaining parameters (ndp->ni_offset, ndp->ni_count) indicate
* how the space for the new entry is to be gotten.
*/
direnter(ip, ndp)
struct inode *ip;
register struct nameidata *ndp;
{
register struct direct *ep, *nep;
register struct inode *dp = VTOI(ndp->ni_dvp);
struct buf *bp;
int loc, spacefree, error = 0;
u_int dsize;
int newentrysize;
char *dirbuf;
ndp->ni_dent.d_ino = ip->i_number;
newentrysize = DIRSIZ(&ndp->ni_dent);
if (ndp->ni_count == 0) {
/*
* If ndp->ni_count is 0, then namei could find no space in the
* directory. In this case ndp->ni_offset will be on a directory
* block boundary and we will write the new entry into a fresh
* block.
*/
if (ndp->ni_offset&(DIRBLKSIZ-1))
panic("wdir: newblk");
ndp->ni_dent.d_reclen = DIRBLKSIZ;
error = rdwri(UIO_WRITE, dp, (caddr_t)&ndp->ni_dent,
newentrysize, ndp->ni_offset, UIO_SYSSPACE, ndp->ni_cred,
(int *)0);
if (DIRBLKSIZ > dp->i_fs->fs_fsize)
panic("wdir: blksize"); /* XXX - should grow w/balloc */
else
dp->i_size = roundup(dp->i_size, DIRBLKSIZ);
iput(dp);
return (error);
}
/*
* If ndp->ni_count is non-zero, then namei found space for the new
* entry in the range ndp->ni_offset to ndp->ni_offset + ndp->ni_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 (ndp->ni_offset + ndp->ni_count > dp->i_size)
dp->i_size = ndp->ni_offset + ndp->ni_count;
/*
* Get the block containing the space for the new directory entry.
*/
if (error = blkatoff(dp, ndp->ni_offset, (char **)&dirbuf, &bp)) {
iput(dp);
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
* ndp->ni_offset to ndp->ni_offset+ndp->ni_count would yield the space.
*/
ep = (struct direct *)dirbuf;
dsize = DIRSIZ(ep);
spacefree = ep->d_reclen - dsize;
for (loc = ep->d_reclen; loc < ndp->ni_count; ) {
nep = (struct direct *)(dirbuf + loc);
if (ep->d_ino) {
/* trim the existing slot */
ep->d_reclen = dsize;
ep = (struct direct *)((char *)ep + dsize);
} else {
/* overwrite; nothing there; header is ours */
spacefree += dsize;
}
dsize = DIRSIZ(nep);
spacefree += nep->d_reclen - dsize;
loc += nep->d_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->d_ino == 0) {
if (spacefree + dsize < newentrysize)
panic("wdir: compact1");
ndp->ni_dent.d_reclen = spacefree + dsize;
} else {
if (spacefree < newentrysize)
panic("wdir: compact2");
ndp->ni_dent.d_reclen = spacefree;
ep->d_reclen = dsize;
ep = (struct direct *)((char *)ep + dsize);
}
bcopy((caddr_t)&ndp->ni_dent, (caddr_t)ep, (u_int)newentrysize);
error = bwrite(bp);
dp->i_flag |= IUPD|ICHG;
if (ndp->ni_endoff && ndp->ni_endoff < dp->i_size)
error = itrunc(dp, (u_long)ndp->ni_endoff);
iput(dp);
return (error);
}
/*
* Remove a directory entry after a call to namei, using the
* parameters which it left in the u. area. The u. entry
* ni_offset contains the offset into the directory of the
* entry to be eliminated. The ni_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 isn't 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.
*/
dirremove(ndp)
register struct nameidata *ndp;
{
register struct inode *dp = VTOI(ndp->ni_dvp);
struct direct *ep;
struct buf *bp;
int error;
if (ndp->ni_count == 0) {
/*
* First entry in block: set d_ino to zero.
*/
ndp->ni_dent.d_ino = 0;
error = rdwri(UIO_WRITE, dp, (caddr_t)&ndp->ni_dent,
(int)DIRSIZ(&ndp->ni_dent), ndp->ni_offset, UIO_SYSSPACE,
ndp->ni_cred, (int *)0);
} else {
/*
* Collapse new free space into previous entry.
*/
if (error = blkatoff(dp, ndp->ni_offset - ndp->ni_count,
(char **)&ep, &bp)) {
return (error);
}
ep->d_reclen += ndp->ni_dent.d_reclen;
error = bwrite(bp);
dp->i_flag |= IUPD|ICHG;
}
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.
*/
dirrewrite(dp, ip, ndp)
struct inode *dp, *ip;
struct nameidata *ndp;
{
ndp->ni_dent.d_ino = ip->i_number;
return (rdwri(UIO_WRITE, dp, (caddr_t)&ndp->ni_dent,
(int)DIRSIZ(&ndp->ni_dent), ndp->ni_offset, UIO_SYSSPACE,
ndp->ni_cred, (int *)0));
}
/*
* Return buffer with contents of block "offset"
* from the beginning of directory "ip". If "res"
* is non-zero, fill it in with a pointer to the
* remaining space in the directory.
*/
blkatoff(ip, offset, res, bpp)
struct inode *ip;
off_t offset;
char **res;
struct buf **bpp;
{
register struct fs *fs = ip->i_fs;
daddr_t lbn = lblkno(fs, offset);
int bsize = blksize(fs, ip, lbn);
struct buf *bp;
daddr_t bn;
int error;
*bpp = 0;
if (error = bmap(ip, lbn, &bn, (daddr_t *)0, (int *)0))
return (error);
if (bn == (daddr_t)-1) {
dirbad(ip, offset, "hole in dir");
return (EIO);
}
#ifdef SECSIZE
bp = bread(ip->i_dev, fsbtodb(fs, bn), bsize, fs->fs_dbsize);
#else SECSIZE
error = bread(ip->i_devvp, bn, bsize, &bp);
if (error) {
brelse(bp);
return (error);
}
if (res)
*res = bp->b_un.b_addr + blkoff(fs, offset);
*bpp = bp;
return (0);
}
/*
* 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.
*/
dirempty(ip, parentino, cred)
register struct inode *ip;
ino_t parentino;
struct ucred *cred;
{
register off_t off;
struct dirtemplate dbuf;
register struct direct *dp = (struct direct *)&dbuf;
int error, count;
#define MINDIRSIZ (sizeof (struct dirtemplate) / 2)
for (off = 0; off < ip->i_size; off += dp->d_reclen) {
error = rdwri(UIO_READ, ip, (caddr_t)dp, MINDIRSIZ, off,
UIO_SYSSPACE, cred, &count);
/*
* 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->d_reclen == 0)
return (0);
/* skip empty entries */
if (dp->d_ino == 0)
continue;
/* accept only "." and ".." */
if (dp->d_namlen > 2)
return (0);
if (dp->d_name[0] != '.')
return (0);
/*
* At this point d_namlen must be 1 or 2.
* 1 implies ".", 2 implies ".." if second
* char is also "."
*/
if (dp->d_namlen == 1)
continue;
if (dp->d_name[1] == '.' && dp->d_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 iput() before returning.
*/
checkpath(source, target, cred)
struct inode *source, *target;
struct ucred *cred;
{
struct dirtemplate dirbuf;
struct inode *ip;
int error = 0;
ip = target;
if (ip->i_number == source->i_number) {
error = EEXIST;
goto out;
}
if (ip->i_number == ROOTINO)
goto out;
for (;;) {
if ((ip->i_mode&IFMT) != IFDIR) {
error = ENOTDIR;
break;
}
error = rdwri(UIO_READ, ip, (caddr_t)&dirbuf,
sizeof (struct dirtemplate), (off_t)0, UIO_SYSSPACE,
cred, (int *)0);
if (error != 0)
break;
if (dirbuf.dotdot_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 == ROOTINO)
break;
iput(ip);
if (error = iget(ip, dirbuf.dotdot_ino, &ip))
break;
}
out:
if (error == ENOTDIR)
printf("checkpath: .. not a directory\n");
if (ip != NULL)
iput(ip);
return (error);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.