Line data    Source code

       1             : /*
       2             :    Unix SMB/CIFS implementation.
       3             : 
       4             :    trivial database library
       5             : 
       6             :    Copyright (C) Jeremy Allison                    2006
       7             : 
       8             :      ** NOTE! The following LGPL license applies to the tdb
       9             :      ** library. This does NOT imply that all of Samba is released
      10             :      ** under the LGPL
      11             : 
      12             :    This library is free software; you can redistribute it and/or
      13             :    modify it under the terms of the GNU Lesser General Public
      14             :    License as published by the Free Software Foundation; either
      15             :    version 3 of the License, or (at your option) any later version.
      16             : 
      17             :    This library is distributed in the hope that it will be useful,
      18             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      19             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      20             :    Lesser General Public License for more details.
      21             : 
      22             :    You should have received a copy of the GNU Lesser General Public
      23             :    License along with this library; if not, see <http://www.gnu.org/licenses/>.
      24             : */
      25             : 
      26             : #include "tdb_private.h"
      27             : 
      28             : /* Check the freelist is good and contains no loops.
      29             :    Very memory intensive - only do this as a consistency
      30             :    checker. Heh heh - uses an in memory tdb as the storage
      31             :    for the "seen" record list. For some reason this strikes
      32             :    me as extremely clever as I don't have to write another tree
      33             :    data structure implementation :-).
      34             :  */
      35             : 
      36          24 : static int seen_insert(struct tdb_context *mem_tdb, tdb_off_t rec_ptr)
      37             : {
      38             :         TDB_DATA key;
      39             : 
      40          24 :         key.dptr = (unsigned char *)&rec_ptr;
      41          24 :         key.dsize = sizeof(rec_ptr);
      42          24 :         return tdb_store(mem_tdb, key, tdb_null, TDB_INSERT);
      43             : }
      44             : 
      45          12 : _PUBLIC_ int tdb_validate_freelist(struct tdb_context *tdb, int *pnum_entries)
      46             : {
      47          12 :         struct tdb_context *mem_tdb = NULL;
      48             :         struct tdb_record rec;
      49             :         tdb_off_t rec_ptr, last_ptr;
      50          12 :         int ret = -1;
      51             : 
      52          12 :         *pnum_entries = 0;
      53             : 
      54          12 :         mem_tdb = tdb_open("flval", tdb->hash_size,
      55             :                                 TDB_INTERNAL, O_RDWR, 0600);
      56          12 :         if (!mem_tdb) {
      57           0 :                 return -1;
      58             :         }
      59             : 
      60          12 :         if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
      61           0 :                 tdb_close(mem_tdb);
      62           0 :                 return 0;
      63             :         }
      64             : 
      65          12 :         last_ptr = FREELIST_TOP;
      66             : 
      67             :         /* Store the FREELIST_TOP record. */
      68          12 :         if (seen_insert(mem_tdb, last_ptr) == -1) {
      69           0 :                 tdb->ecode = TDB_ERR_CORRUPT;
      70           0 :                 ret = -1;
      71           0 :                 goto fail;
      72             :         }
      73             : 
      74             :         /* read in the freelist top */
      75          12 :         if (tdb_ofs_read(tdb, FREELIST_TOP, &rec_ptr) == -1) {
      76           0 :                 goto fail;
      77             :         }
      78             : 
      79          30 :         while (rec_ptr) {
      80             : 
      81             :                 /* If we can't store this record (we've seen it
      82             :                    before) then the free list has a loop and must
      83             :                    be corrupt. */
      84             : 
      85          12 :                 if (seen_insert(mem_tdb, rec_ptr)) {
      86           0 :                         tdb->ecode = TDB_ERR_CORRUPT;
      87           0 :                         ret = -1;
      88           0 :                         goto fail;
      89             :                 }
      90             : 
      91          12 :                 if (tdb_rec_free_read(tdb, rec_ptr, &rec) == -1) {
      92           0 :                         goto fail;
      93             :                 }
      94             : 
      95             :                 /* move to the next record */
      96          12 :                 rec_ptr = rec.next;
      97          12 :                 *pnum_entries += 1;
      98             :         }
      99             : 
     100          12 :         ret = 0;
     101             : 
     102          12 :   fail:
     103             : 
     104          12 :         tdb_close(mem_tdb);
     105          12 :         tdb_unlock(tdb, -1, F_WRLCK);
     106          12 :         return ret;
     107             : }