FreeBSD/Linux Kernel Cross Reference
sys/ufs/ufs/ufs_lookup.c

     /*-
      * 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.
     * 4. 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        8.15 (Berkeley) 6/16/95
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include "opt_ffs_broken_fixme.h"
    #include "opt_ufs.h"
    #include "opt_quota.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/namei.h>
    #include <sys/bio.h>
    #include <sys/buf.h>
    #include <sys/proc.h>
    #include <sys/stat.h>
    #include <sys/mount.h>
    #include <sys/vnode.h>
    #include <sys/sysctl.h>
    
    #include <vm/vm.h>
    #include <vm/vm_extern.h>
    
    #include <ufs/ufs/extattr.h>
    #include <ufs/ufs/quota.h>
    #include <ufs/ufs/inode.h>
    #include <ufs/ufs/dir.h>
    #ifdef UFS_DIRHASH
    #include <ufs/ufs/dirhash.h>
    #endif
    #include <ufs/ufs/ufsmount.h>
    #include <ufs/ufs/ufs_extern.h>
    
    #ifdef DIAGNOSTIC
    static int      dirchk = 1;
    #else
    static int      dirchk = 0;
    #endif
    
    SYSCTL_INT(_debug, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
    
    /* true if old FS format...*/
    #define OFSFMT(vp)      ((vp)->v_mount->mnt_maxsymlinklen <= 0)
    
    /*
     * Convert a component of a pathname into a pointer to a locked inode.
     * This is a very central and rather complicated routine.
     * If the filesystem 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.
     *
     * This routine is actually used as VOP_CACHEDLOOKUP method, and the
     * filesystem employs the generic vfs_cache_lookup() as VOP_LOOKUP
     * method.
    *
    * vfs_cache_lookup() performs the following for us:
    *      check that it is a directory
    *      check accessibility of directory
    *      check for modification attempts on read-only mounts
    *      if name found in cache
    *          if at end of path and deleting or creating
    *              drop it
    *           else
    *              return name.
    *      return VOP_CACHEDLOOKUP()
    *
    * Overall outline of ufs_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
   ufs_lookup(ap)
           struct vop_cachedlookup_args /* {
                   struct vnode *a_dvp;
                   struct vnode **a_vpp;
                   struct componentname *a_cnp;
           } */ *ap;
   {
           struct vnode *vdp;              /* vnode for directory being searched */
           struct inode *dp;               /* inode for directory being searched */
           struct buf *bp;                 /* a buffer of directory entries */
           struct direct *ep;              /* the current directory entry */
           int entryoffsetinblock;         /* offset of ep in bp's buffer */
           enum {NONE, COMPACT, FOUND} slotstatus;
           doff_t slotoffset;              /* offset of area with free space */
           doff_t i_diroff;                /* cached i_diroff value. */
           doff_t i_offset;                /* cached i_offset value. */
           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 */
           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 namlen, error;
           struct vnode **vpp = ap->a_vpp;
           struct componentname *cnp = ap->a_cnp;
           struct ucred *cred = cnp->cn_cred;
           int flags = cnp->cn_flags;
           int nameiop = cnp->cn_nameiop;
           struct thread *td = cnp->cn_thread;
           ino_t ino;
           int ltype;
   
           bp = NULL;
           slotoffset = -1;
   /*
    *  XXX there was a soft-update diff about this I couldn't merge.
    * I think this was the equiv.
    */
           *vpp = NULL;
   
           vdp = ap->a_dvp;
           dp = VTOI(vdp);
   
           /*
            * Create a vm object if vmiodirenable is enabled.
            * Alternatively we could call vnode_create_vobject
            * in VFS_VGET but we could end up creating objects
            * that are never used.
            */
           vnode_create_vobject(vdp, DIP(dp, i_size), cnp->cn_thread);
   
           /*
            * 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.
            */
           ino = 0;
           i_diroff = dp->i_diroff;
           slotstatus = FOUND;
           slotfreespace = slotsize = slotneeded = 0;
           if ((nameiop == CREATE || nameiop == RENAME) &&
               (flags & ISLASTCN)) {
                   slotstatus = NONE;
                   slotneeded = DIRECTSIZ(cnp->cn_namelen);
           }
           bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
   
   #ifdef UFS_DIRHASH
           /*
            * Use dirhash for fast operations on large directories. The logic
            * to determine whether to hash the directory is contained within
            * ufsdirhash_build(); a zero return means that it decided to hash
            * this directory and it successfully built up the hash table.
            */
           if (ufsdirhash_build(dp) == 0) {
                   /* Look for a free slot if needed. */
                   enduseful = dp->i_size;
                   if (slotstatus != FOUND) {
                           slotoffset = ufsdirhash_findfree(dp, slotneeded,
                               &slotsize);
                           if (slotoffset >= 0) {
                                   slotstatus = COMPACT;
                                   enduseful = ufsdirhash_enduseful(dp);
                                   if (enduseful < 0)
                                           enduseful = dp->i_size;
                           }
                   }
                   /* Look up the component. */
                   numdirpasses = 1;
                   entryoffsetinblock = 0; /* silence compiler warning */
                   switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
                       &i_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) {
                   case 0:
                           ep = (struct direct *)((char *)bp->b_data +
                               (i_offset & bmask));
                           goto foundentry;
                   case ENOENT:
                           i_offset = roundup2(dp->i_size, DIRBLKSIZ);
                           goto notfound;
                   default:
                           /* Something failed; just do a linear search. */
                           break;
                   }
           }
   #endif /* UFS_DIRHASH */
           /*
            * 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 = UFS_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 ((i_offset & bmask) == 0) {
                           if (bp != NULL)
                                   brelse(bp);
                           error =
                               UFS_BLKATOFF(vdp, (off_t)i_offset, NULL, &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 *)((char *)bp->b_data + entryoffsetinblock);
                   if (ep->d_reclen == 0 || ep->d_reclen >
                       DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
                       (dirchk && ufs_dirbadentry(vdp, ep, entryoffsetinblock))) {
                           int i;
   
                           ufs_dirbad(dp, i_offset, "mangled entry");
                           i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
                           i_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(OFSFMT(vdp), ep);
                           if (size > 0) {
                                   if (size >= slotneeded) {
                                           slotstatus = FOUND;
                                           slotoffset = i_offset;
                                           slotsize = ep->d_reclen;
                                   } else if (slotstatus == NONE) {
                                           slotfreespace += size;
                                           if (slotoffset == -1)
                                                   slotoffset = i_offset;
                                           if (slotfreespace >= slotneeded) {
                                                   slotstatus = COMPACT;
                                                   slotsize = i_offset +
                                                         ep->d_reclen - slotoffset;
                                           }
                                   }
                           }
                   }
   
                   /*
                    * Check for a name match.
                    */
                   if (ep->d_ino) {
   #                       if (BYTE_ORDER == LITTLE_ENDIAN)
                                   if (OFSFMT(vdp))
                                           namlen = ep->d_type;
                                   else
                                           namlen = ep->d_namlen;
   #                       else
                                   namlen = ep->d_namlen;
   #                       endif
                           if (namlen == cnp->cn_namelen &&
                                   (cnp->cn_nameptr[0] == ep->d_name[0]) &&
                               !bcmp(cnp->cn_nameptr, ep->d_name,
                                   (unsigned)namlen)) {
   #ifdef UFS_DIRHASH
   foundentry:
   #endif
                                   /*
                                    * Save directory entry's inode number and
                                    * reclen in ndp->ni_ufs area, and release
                                    * directory buffer.
                                    */
                                   if (vdp->v_mount->mnt_maxsymlinklen > 0 &&
                                       ep->d_type == DT_WHT) {
                                           slotstatus = FOUND;
                                           slotoffset = i_offset;
                                           slotsize = ep->d_reclen;
                                           enduseful = dp->i_size;
                                           ap->a_cnp->cn_flags |= ISWHITEOUT;
                                           numdirpasses--;
                                           goto notfound;
                                   }
                                   ino = ep->d_ino;
                                   goto found;
                           }
                   }
                   prevoff = i_offset;
                   i_offset += ep->d_reclen;
                   entryoffsetinblock += ep->d_reclen;
                   if (ep->d_ino)
                           enduseful = i_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--;
                   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 ||
                (nameiop == DELETE &&
                 (ap->a_cnp->cn_flags & DOWHITEOUT) &&
                 (ap->a_cnp->cn_flags & ISWHITEOUT))) &&
               (flags & ISLASTCN) && dp->i_effnlink != 0) {
                   /*
                    * Access for write is interpreted as allowing
                    * creation of files in the directory.
                    */
                   error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
                   if (error)
                           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 (slotstatus == NONE) {
                           dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
                           dp->i_count = 0;
                           enduseful = dp->i_offset;
                   } else if (nameiop == DELETE) {
                           dp->i_offset = slotoffset;
                           if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
                                   dp->i_count = 0;
                           else
                                   dp->i_count = dp->i_offset - prevoff;
                   } else {
                           dp->i_offset = slotoffset;
                           dp->i_count = slotsize;
                           if (enduseful < slotoffset + slotsize)
                                   enduseful = slotoffset + 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) && nameiop != CREATE)
                   cache_enter(vdp, *vpp, cnp);
           return (ENOENT);
   
   found:
           if (numdirpasses == 2)
                   nchstats.ncs_pass2++;
           /*
            * Check that directory length properly reflects presence
            * of this entry.
            */
           if (i_offset + DIRSIZ(OFSFMT(vdp), ep) > dp->i_size) {
                   ufs_dirbad(dp, i_offset, "i_size too small");
                   dp->i_size = i_offset + DIRSIZ(OFSFMT(vdp), ep);
                   DIP_SET(dp, i_size, dp->i_size);
                   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 = i_offset &~ (DIRBLKSIZ - 1);
   
           /*
            * 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.
                    */
                   error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
                   if (error)
                           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 (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) &&
                       VOP_ACCESS(vdp, VADMIN, cred, cnp->cn_thread) &&
                       VOP_ACCESS(tdp, VADMIN, cred, cnp->cn_thread)) {
                           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)))
                           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 ((error = VFS_VGET(vdp->v_mount, ino,
                       LK_EXCLUSIVE, &tdp)) != 0)
                           return (error);
                   *vpp = 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.
            * 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 filesystem 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 (error)
                           return (error);
                   *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, td)) {
                           if (ltype == LK_EXCLUSIVE)
                                   vn_lock(vdp, LK_UPGRADE | LK_RETRY, td);
                           else /* if (ltype == LK_SHARED) */
                                   vn_lock(vdp, LK_DOWNGRADE | LK_RETRY, td);
                   }
                   *vpp = vdp;
           } else {
                   error = VFS_VGET(pdp->v_mount, ino, cnp->cn_lkflags, &tdp);
                   if (error)
                           return (error);
                   *vpp = tdp;
           }
   
           /*
            * Insert name into cache if appropriate.
            */
           if (cnp->cn_flags & MAKEENTRY)
                   cache_enter(vdp, *vpp, cnp);
           return (0);
   }
   
   void
   ufs_dirbad(ip, offset, how)
           struct inode *ip;
           doff_t offset;
           char *how;
   {
           struct mount *mp;
   
           mp = ITOV(ip)->v_mount;
           if ((mp->mnt_flag & MNT_RDONLY) == 0)
                   panic("ufs_dirbad: %s: bad dir ino %lu at offset %ld: %s",
                       mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how);
           else
                   (void)printf("%s: bad dir ino %lu at offset %ld: %s\n",
                       mp->mnt_stat.f_mntonname, (u_long)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
    */
   int
   ufs_dirbadentry(dp, ep, entryoffsetinblock)
           struct vnode *dp;
           struct direct *ep;
           int entryoffsetinblock;
   {
           int i, namlen;
   
   #       if (BYTE_ORDER == LITTLE_ENDIAN)
                   if (OFSFMT(dp))
                           namlen = ep->d_type;
                   else
                           namlen = ep->d_namlen;
   #       else
                   namlen = ep->d_namlen;
   #       endif
           if ((ep->d_reclen & 0x3) != 0 ||
               ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
               ep->d_reclen < DIRSIZ(OFSFMT(dp), ep) || namlen > MAXNAMLEN) {
                   /*return (1); */
                   printf("First bad\n");
                   goto bad;
           }
           if (ep->d_ino == 0)
                   return (0);
           for (i = 0; i < namlen; i++)
                   if (ep->d_name[i] == '\0') {
                           /*return (1); */
                           printf("Second bad\n");
                           goto bad;
                   }
           if (ep->d_name[i])
                   goto bad;
           return (0);
   bad:
           return (1);
   }
   
   /*
    * Construct a new directory entry after a call to namei, using the
    * parameters that it left in the componentname argument cnp. The
    * argument ip is the inode to which the new directory entry will refer.
    */
   void
   ufs_makedirentry(ip, cnp, newdirp)
           struct inode *ip;
           struct componentname *cnp;
           struct direct *newdirp;
   {
   
   #ifdef INVARIANTS
           if ((cnp->cn_flags & SAVENAME) == 0)
                   panic("ufs_makedirentry: missing name");
   #endif
           newdirp->d_ino = ip->i_number;
           newdirp->d_namlen = cnp->cn_namelen;
           bcopy(cnp->cn_nameptr, newdirp->d_name, (unsigned)cnp->cn_namelen + 1);
           if (ITOV(ip)->v_mount->mnt_maxsymlinklen > 0)
                   newdirp->d_type = IFTODT(ip->i_mode);
           else {
                   newdirp->d_type = 0;
   #               if (BYTE_ORDER == LITTLE_ENDIAN)
                           { u_char tmp = newdirp->d_namlen;
                           newdirp->d_namlen = newdirp->d_type;
                           newdirp->d_type = tmp; }
   #               endif
           }
   }
   
   /*
    * Write a directory entry after a call to namei, using the parameters
    * that it left in nameidata. The argument dirp is the new directory
    * entry contents. 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.
    * Non-null bp indicates that a directory is being created (for the
    * soft dependency code).
    */
   int
   ufs_direnter(dvp, tvp, dirp, cnp, newdirbp)
           struct vnode *dvp;
           struct vnode *tvp;
           struct direct *dirp;
           struct componentname *cnp;
           struct buf *newdirbp;
   {
           struct ucred *cr;
           struct thread *td;
           int newentrysize;
           struct inode *dp;
           struct buf *bp;
           u_int dsize;
           struct direct *ep, *nep;
           int error, ret, blkoff, loc, spacefree, flags, namlen;
           char *dirbuf;
   
           td = curthread; /* XXX */
           cr = td->td_ucred;
   
           dp = VTOI(dvp);
           newentrysize = DIRSIZ(OFSFMT(dvp), dirp);
   
           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("ufs_direnter: newblk");
                   flags = BA_CLRBUF;
                   if (!DOINGSOFTDEP(dvp) && !DOINGASYNC(dvp))
                           flags |= IO_SYNC;
   #ifdef QUOTA
                   if ((error = getinoquota(dp)) != 0) {
                           if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
                                   bdwrite(newdirbp);
                           return (error);
                   }
   #endif
                   if ((error = UFS_BALLOC(dvp, (off_t)dp->i_offset, DIRBLKSIZ,
                       cr, flags, &bp)) != 0) {
                           if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
                                   bdwrite(newdirbp);
                           return (error);
                   }
                   dp->i_size = dp->i_offset + DIRBLKSIZ;
                   DIP_SET(dp, i_size, dp->i_size);
                   dp->i_flag |= IN_CHANGE | IN_UPDATE;
                   vnode_pager_setsize(dvp, (u_long)dp->i_size);
                   dirp->d_reclen = DIRBLKSIZ;
                   blkoff = dp->i_offset &
                       (VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_iosize - 1);
                   bcopy((caddr_t)dirp, (caddr_t)bp->b_data + blkoff,newentrysize);
   #ifdef UFS_DIRHASH
                   if (dp->i_dirhash != NULL) {
                           ufsdirhash_newblk(dp, dp->i_offset);
                           ufsdirhash_add(dp, dirp, dp->i_offset);
                           ufsdirhash_checkblock(dp, (char *)bp->b_data + blkoff,
                               dp->i_offset);
                   }
   #endif
                   if (DOINGSOFTDEP(dvp)) {
                           /*
                            * Ensure that the entire newly allocated block is a
                            * valid directory so that future growth within the
                            * block does not have to ensure that the block is
                            * written before the inode.
                            */
                           blkoff += DIRBLKSIZ;
                           while (blkoff < bp->b_bcount) {
                                   ((struct direct *)
                                      (bp->b_data + blkoff))->d_reclen = DIRBLKSIZ;
                                   blkoff += DIRBLKSIZ;
                           }
                           if (softdep_setup_directory_add(bp, dp, dp->i_offset,
                               dirp->d_ino, newdirbp, 1) == 0) {
                                   bdwrite(bp);
                                   return (UFS_UPDATE(dvp, 0));
                           }
                           /* We have just allocated a directory block in an
                            * indirect block. Rather than tracking when it gets
                            * claimed by the inode, we simply do a VOP_FSYNC
                            * now to ensure that it is there (in case the user
                            * does a future fsync). Note that we have to unlock
                            * the inode for the entry that we just entered, as
                            * the VOP_FSYNC may need to lock other inodes which
                            * can lead to deadlock if we also hold a lock on
                            * the newly entered node.
                            */
                           if ((error = bwrite(bp)))
                                   return (error);
                           if (tvp != NULL)
                                   VOP_UNLOCK(tvp, 0, td);
                           error = VOP_FSYNC(dvp, MNT_WAIT, td);
                           if (tvp != NULL)
                                   vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, td);
                           return (error);
                   }
                   if (DOINGASYNC(dvp)) {
                           bdwrite(bp);
                           return (UFS_UPDATE(dvp, 0));
                   }
                   error = bwrite(bp);
                   ret = UFS_UPDATE(dvp, 1);
                   if (error == 0)
                           return (ret);
                   return (error);
           }
   
           /*
            * 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;
                   DIP_SET(dp, i_size, dp->i_size);
           }
           /*
            * Get the block containing the space for the new directory entry.
            */
           error = UFS_BLKATOFF(dvp, (off_t)dp->i_offset, &dirbuf, &bp);
           if (error) {
                   if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
                           bdwrite(newdirbp);
                   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.
            */
           ep = (struct direct *)dirbuf;
           dsize = ep->d_ino ? DIRSIZ(OFSFMT(dvp), ep) : 0;
           spacefree = ep->d_reclen - dsize;
           for (loc = ep->d_reclen; loc < dp->i_count; ) {
                   nep = (struct direct *)(dirbuf + loc);
   
                   /* Trim the existing slot (NB: dsize may be zero). */
                   ep->d_reclen = dsize;
                   ep = (struct direct *)((char *)ep + dsize);
   
                   /* Read nep->d_reclen now as the bcopy() may clobber it. */
                   loc += nep->d_reclen;
                   if (nep->d_ino == 0) {
                           /*
                            * A mid-block unused entry. Such entries are
                            * never created by the kernel, but fsck_ffs
                            * can create them (and it doesn't fix them).
                            *
                            * Add up the free space, and initialise the
                            * relocated entry since we don't bcopy it.
                            */
                           spacefree += nep->d_reclen;
                           ep->d_ino = 0;
                           dsize = 0;
                           continue;
                   }
                   dsize = DIRSIZ(OFSFMT(dvp), nep);
                   spacefree += nep->d_reclen - dsize;
   #ifdef UFS_DIRHASH
                   if (dp->i_dirhash != NULL)
                           ufsdirhash_move(dp, nep,
                               dp->i_offset + ((char *)nep - dirbuf),
                               dp->i_offset + ((char *)ep - dirbuf));
   #endif
                   if (DOINGSOFTDEP(dvp))
                           softdep_change_directoryentry_offset(dp, dirbuf,
                               (caddr_t)nep, (caddr_t)ep, dsize); 
                   else
                           bcopy((caddr_t)nep, (caddr_t)ep, dsize);
           }
           /*
            * Here, `ep' points to a directory entry containing `dsize' in-use
            * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0,
            * then the entry is completely unused (dsize == 0). The value
            * of ep->d_reclen is always indeterminate.
            *
            * Update the pointer fields in the previous entry (if any),
            * copy in the new entry, and write out the block.
            */
   #       if (BYTE_ORDER == LITTLE_ENDIAN)
                   if (OFSFMT(dvp))
                           namlen = ep->d_type;
                   else
                           namlen = ep->d_namlen;
   #       else
                   namlen = ep->d_namlen;
   #       endif
           if (ep->d_ino == 0 ||
               (ep->d_ino == WINO && namlen == dirp->d_namlen &&
                bcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) {
                   if (spacefree + dsize < newentrysize)
                           panic("ufs_direnter: compact1");
                   dirp->d_reclen = spacefree + dsize;
           } else {
                   if (spacefree < newentrysize)
                           panic("ufs_direnter: compact2");
                   dirp->d_reclen = spacefree;
                   ep->d_reclen = dsize;
                   ep = (struct direct *)((char *)ep + dsize);
           }
   #ifdef UFS_DIRHASH
           if (dp->i_dirhash != NULL && (ep->d_ino == 0 ||
               dirp->d_reclen == spacefree))
                   ufsdirhash_add(dp, dirp, dp->i_offset + ((char *)ep - dirbuf));
   #endif
           bcopy((caddr_t)dirp, (caddr_t)ep, (u_int)newentrysize);
   #ifdef UFS_DIRHASH
           if (dp->i_dirhash != NULL)
                   ufsdirhash_checkblock(dp, dirbuf -
                       (dp->i_offset & (DIRBLKSIZ - 1)),
                       dp->i_offset & ~(DIRBLKSIZ - 1));
   #endif
   
           if (DOINGSOFTDEP(dvp)) {
                   (void) softdep_setup_directory_add(bp, dp,
                       dp->i_offset + (caddr_t)ep - dirbuf,
                       dirp->d_ino, newdirbp, 0);
                   bdwrite(bp);
           } else {
                   if (DOINGASYNC(dvp)) {
                           bdwrite(bp);
                           error = 0;
                   } else {
                           error = bwrite(bp);
                   }
           }
           dp->i_flag |= IN_CHANGE | IN_UPDATE;
           /*
            * If all went well, and the directory can be shortened, proceed
            * with the truncation. Note that we have to unlock the inode for
            * the entry that we just entered, as the truncation may need to
            * lock other inodes which can lead to deadlock if we also hold a
            * lock on the newly entered node.
            */
           if (error == 0 && dp->i_endoff && dp->i_endoff < dp->i_size) {
                   if (tvp != NULL)
                           VOP_UNLOCK(tvp, 0, td);
   #ifdef UFS_DIRHASH
                   if (dp->i_dirhash != NULL)
                           ufsdirhash_dirtrunc(dp, dp->i_endoff);
   #endif
                   (void) UFS_TRUNCATE(dvp, (off_t)dp->i_endoff,
                       IO_NORMAL | IO_SYNC, cr, td);
                   if (tvp != NULL)
                           vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, td);
           }
           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
   ufs_dirremove(dvp, ip, flags, isrmdir)
           struct vnode *dvp;
           struct inode *ip;
          int flags;
          int isrmdir;
  {
          struct inode *dp;
          struct direct *ep, *rep;
          struct buf *bp;
          int error;
  
          dp = VTOI(dvp);
  
          if (flags & DOWHITEOUT) {
                  /*
                   * Whiteout entry: set d_ino to WINO.
                   */
                  if ((error =
                      UFS_BLKATOFF(dvp, (off_t)dp->i_offset, (char **)&ep, &bp)) != 0)
                          return (error);
                  ep->d_ino = WINO;
                  ep->d_type = DT_WHT;
                  goto out;
          }
  
          if ((error = UFS_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 direct *)((char *)ep + ep->d_reclen);
  #ifdef UFS_DIRHASH
          /*
           * Remove the dirhash entry. This is complicated by the fact
           * that `ep' is the previous entry when dp->i_count != 0.
           */
          if (dp->i_dirhash != NULL)
                  ufsdirhash_remove(dp, rep, dp->i_offset);
  #endif
          if (dp->i_count == 0) {
                  /*
                   * First entry in block: set d_ino to zero.
                   */
                  ep->d_ino = 0;
          } else {
                  /*
                   * Collapse new free space into previous entry.
                   */
                  ep->d_reclen += rep->d_reclen;
          }
  #ifdef UFS_DIRHASH
          if (dp->i_dirhash != NULL)
                  ufsdirhash_checkblock(dp, (char *)ep -
                      ((dp->i_offset - dp->i_count) & (DIRBLKSIZ - 1)),
                      dp->i_offset & ~(DIRBLKSIZ - 1));
  #endif
  out:
          if (DOINGSOFTDEP(dvp)) {
                  if (ip) {
                          ip->i_effnlink--;
                          softdep_change_linkcnt(ip);
                          softdep_setup_remove(bp, dp, ip, isrmdir);
                  }
                  if (softdep_slowdown(dvp)) {
                          error = bwrite(bp);
                  } else {
                          bdwrite(bp);
                          error = 0;
                  }
          } else {
                  if (ip) {
                          ip->i_effnlink--;
                          ip->i_nlink--;
                          DIP_SET(ip, i_nlink, ip->i_nlink);
                          ip->i_flag |= IN_CHANGE;
                  }
                  if (flags & DOWHITEOUT)
                          error = bwrite(bp);
                  else if (DOINGASYNC(dvp) && dp->i_count != 0) {
                          bdwrite(bp);
                          error = 0;
                  } else
                          error = bwrite(bp);
          }
          dp->i_flag |= IN_CHANGE | IN_UPDATE;
          /*
           * If the last named reference to a snapshot goes away,
           * drop its snapshot reference so that it will be reclaimed
           * when last open reference goes away.
           */
  #if defined(FFS) || defined(IFS)
          if (ip != 0 && (ip->i_flags & SF_SNAPSHOT) != 0 && ip->i_effnlink == 0)
                  ffs_snapgone(ip);
  #endif
          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
  ufs_dirrewrite(dp, oip, newinum, newtype, isrmdir)
          struct inode *dp, *oip;
          ino_t newinum;
          int newtype;
          int isrmdir;
  {
          struct buf *bp;
          struct direct *ep;
          struct vnode *vdp = ITOV(dp);
          int error;
  
          error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset, (char **)&ep, &bp);
          if (error)
                  return (error);
          ep->d_ino = newinum;
          if (!OFSFMT(vdp))
                  ep->d_type = newtype;
          oip->i_effnlink--;
          if (DOINGSOFTDEP(vdp)) {
                  softdep_change_linkcnt(oip);
                  softdep_setup_directory_change(bp, dp, oip, newinum, isrmdir);
                  bdwrite(bp);
          } else {
                  oip->i_nlink--;
                  DIP_SET(oip, i_nlink, oip->i_nlink);
                  oip->i_flag |= IN_CHANGE;
                  if (DOINGASYNC(vdp)) {
                          bdwrite(bp);
                          error = 0;
                  } else {
                          error = bwrite(bp);
                  }
          }
          dp->i_flag |= IN_CHANGE | IN_UPDATE;
          /*
           * If the last named reference to a snapshot goes away,
           * drop its snapshot reference so that it will be reclaimed
           * when last open reference goes away.
           */
  #if defined(FFS) || defined(IFS)
          if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_effnlink == 0)
                  ffs_snapgone(oip);
  #endif
          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
  ufs_dirempty(ip, parentino, cred)
          struct inode *ip;
          ino_t parentino;
          struct ucred *cred;
  {
          doff_t off;
          struct dirtemplate dbuf;
          struct direct *dp = (struct direct *)&dbuf;
          int error, count, namlen;
  #define MINDIRSIZ (sizeof (struct dirtemplate) / 2)
  
          for (off = 0; off < ip->i_size; off += dp->d_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->d_reclen == 0)
                          return (0);
                  /* skip empty entries */
                  if (dp->d_ino == 0 || dp->d_ino == WINO)
                          continue;
                  /* accept only "." and ".." */
  #               if (BYTE_ORDER == LITTLE_ENDIAN)
                          if (OFSFMT(ITOV(ip)))
                                  namlen = dp->d_type;
                          else
                                  namlen = dp->d_namlen;
  #               else
                          namlen = dp->d_namlen;
  #               endif
                  if (namlen > 2)
                          return (0);
                  if (dp->d_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 && dp->d_ino == ip->i_number)
                          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 vput before returning.
   */
  int
  ufs_checkpath(source, target, cred)
          struct inode *source, *target;
          struct ucred *cred;
  {
          struct vnode *vp;
          int error, namlen;
          ino_t rootino;
          struct dirtemplate dirbuf;
  
          vp = ITOV(target);
          if (target->i_number == source->i_number) {
                  error = EEXIST;
                  goto out;
          }
          rootino = ROOTINO;
          error = 0;
          if (target->i_number == rootino)
                  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, (int *)0,
                          (struct thread *)0);
                  if (error != 0)
                          break;
  #               if (BYTE_ORDER == LITTLE_ENDIAN)
                          if (OFSFMT(vp))
                                  namlen = dirbuf.dotdot_type;
                          else
                                  namlen = dirbuf.dotdot_namlen;
  #               else
                          namlen = dirbuf.dotdot_namlen;
  #               endif
                  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 == rootino)
                          break;
                  vput(vp);
                  error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino,
                      LK_EXCLUSIVE, &vp);
                  if (error) {
                          vp = NULL;
                          break;
                  }
          }
  
  out:
          if (error == ENOTDIR)
                  printf("checkpath: .. not a directory\n");
          if (vp != NULL)
                  vput(vp);
          return (error);
  }

Cache object: 23cc37996c8e26e6089bea11569f6e19