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
36static int seen_insert(struct tdb_context *mem_tdb, tdb_off_t rec_ptr)
37{
38	TDB_DATA key, data;
39
40	memset(&data, '\0', sizeof(data));
41	key.dptr = (unsigned char *)&rec_ptr;
42	key.dsize = sizeof(rec_ptr);
43	return tdb_store(mem_tdb, key, data, TDB_INSERT);
44}
45
46int tdb_validate_freelist(struct tdb_context *tdb, int *pnum_entries)
47{
48	struct tdb_context *mem_tdb = NULL;
49	struct tdb_record rec;
50	tdb_off_t rec_ptr, last_ptr;
51	int ret = -1;
52
53	*pnum_entries = 0;
54
55	mem_tdb = tdb_open("flval", tdb->header.hash_size,
56				TDB_INTERNAL, O_RDWR, 0600);
57	if (!mem_tdb) {
58		return -1;
59	}
60
61	if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
62		tdb_close(mem_tdb);
63		return 0;
64	}
65
66	last_ptr = FREELIST_TOP;
67
68	/* Store the FREELIST_TOP record. */
69	if (seen_insert(mem_tdb, last_ptr) == -1) {
70		tdb->ecode = TDB_ERR_CORRUPT;
71		ret = -1;
72		goto fail;
73	}
74
75	/* read in the freelist top */
76	if (tdb_ofs_read(tdb, FREELIST_TOP, &rec_ptr) == -1) {
77		goto fail;
78	}
79
80	while (rec_ptr) {
81
82		/* If we can't store this record (we've seen it
83		   before) then the free list has a loop and must
84		   be corrupt. */
85
86		if (seen_insert(mem_tdb, rec_ptr)) {
87			tdb->ecode = TDB_ERR_CORRUPT;
88			ret = -1;
89			goto fail;
90		}
91
92		if (tdb_rec_free_read(tdb, rec_ptr, &rec) == -1) {
93			goto fail;
94		}
95
96		/* move to the next record */
97		last_ptr = rec_ptr;
98		rec_ptr = rec.next;
99		*pnum_entries += 1;
100	}
101
102	ret = 0;
103
104  fail:
105
106	tdb_close(mem_tdb);
107	tdb_unlock(tdb, -1, F_WRLCK);
108	return ret;
109}
110