/*

   Unix SMB/CIFS implementation.

   trivial database library

   Copyright (C) Jeremy Allison                    2006

     ** NOTE! The following LGPL license applies to the tdb

     ** library. This does NOT imply that all of Samba is released

     ** under the LGPL

   This library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 3 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with this library; if not, see <http://www.gnu.org/licenses/>.

*/

#include "tdb_private.h"

/* Check the freelist is good and contains no loops.

   Very memory intensive - only do this as a consistency

   checker. Heh heh - uses an in memory tdb as the storage

   for the "seen" record list. For some reason this strikes

   me as extremely clever as I don't have to write another tree

   data structure implementation :-).

 */

static int seen_insert(struct tdb_context *mem_tdb, tdb_off_t rec_ptr)

{

  TDB_DATA key;

  key.dptr = (unsigned char *)&rec_ptr;

  key.dsize = sizeof(rec_ptr);

  return tdb_store(mem_tdb, key, tdb_null, TDB_INSERT);

}

_PUBLIC_ int tdb_validate_freelist(struct tdb_context *tdb, int *pnum_entries)

{

  struct tdb_context *mem_tdb = NULL;

  struct tdb_record rec;

  tdb_off_t rec_ptr, last_ptr;

  int ret = -1;

  *pnum_entries = 0;

  mem_tdb = tdb_open("flval", tdb->hash_size,

        TDB_INTERNAL, O_RDWR, 0600);

  if (!mem_tdb) {

    return -1;

  }

  if (tdb_lock(tdb, -1, F_WRLCK) == -1) {

    tdb_close(mem_tdb);

    return 0;

  }

  last_ptr = FREELIST_TOP;

  /* Store the FREELIST_TOP record. */

  if (seen_insert(mem_tdb, last_ptr) == -1) {

    tdb->ecode = TDB_ERR_CORRUPT;

    ret = -1;

    goto fail;

  }

  /* read in the freelist top */

  if (tdb_ofs_read(tdb, FREELIST_TOP, &rec_ptr) == -1) {

    goto fail;

  }

  while (rec_ptr) {

    /* If we can't store this record (we've seen it

       before) then the free list has a loop and must

       be corrupt. */

    if (seen_insert(mem_tdb, rec_ptr)) {

      tdb->ecode = TDB_ERR_CORRUPT;

      ret = -1;

      goto fail;

    }

    if (tdb_rec_free_read(tdb, rec_ptr, &rec) == -1) {

      goto fail;

    }

    /* move to the next record */

    rec_ptr = rec.next;

    *pnum_entries += 1;

  }

  ret = 0;

  fail:

  tdb_close(mem_tdb);

  tdb_unlock(tdb, -1, F_WRLCK);

  return ret;

}