1/* txn-table.c : operations on the `transactions' table
2 *
3 * ====================================================================
4 *    Licensed to the Apache Software Foundation (ASF) under one
5 *    or more contributor license agreements.  See the NOTICE file
6 *    distributed with this work for additional information
7 *    regarding copyright ownership.  The ASF licenses this file
8 *    to you under the Apache License, Version 2.0 (the
9 *    "License"); you may not use this file except in compliance
10 *    with the License.  You may obtain a copy of the License at
11 *
12 *      http://www.apache.org/licenses/LICENSE-2.0
13 *
14 *    Unless required by applicable law or agreed to in writing,
15 *    software distributed under the License is distributed on an
16 *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 *    KIND, either express or implied.  See the License for the
18 *    specific language governing permissions and limitations
19 *    under the License.
20 * ====================================================================
21 */
22
23#include <string.h>
24#include <assert.h>
25
26#include "bdb_compat.h"
27
28#include "svn_pools.h"
29#include "private/svn_skel.h"
30
31#include "dbt.h"
32#include "../err.h"
33#include "../fs.h"
34#include "../key-gen.h"
35#include "../util/fs_skels.h"
36#include "../trail.h"
37#include "../../libsvn_fs/fs-loader.h"
38#include "bdb-err.h"
39#include "txn-table.h"
40
41#include "svn_private_config.h"
42
43
44static svn_boolean_t
45is_committed(transaction_t *txn)
46{
47  return (txn->kind == transaction_kind_committed);
48}
49
50
51int
52svn_fs_bdb__open_transactions_table(DB **transactions_p,
53                                    DB_ENV *env,
54                                    svn_boolean_t create)
55{
56  const u_int32_t open_flags = (create ? (DB_CREATE | DB_EXCL) : 0);
57  DB *txns;
58
59  BDB_ERR(svn_fs_bdb__check_version());
60  BDB_ERR(db_create(&txns, env, 0));
61  BDB_ERR((txns->open)(SVN_BDB_OPEN_PARAMS(txns, NULL),
62                       "transactions", 0, DB_BTREE,
63                       open_flags, 0666));
64
65  /* Create the `next-key' table entry.  */
66  if (create)
67  {
68    DBT key, value;
69
70    BDB_ERR(txns->put(txns, 0,
71                      svn_fs_base__str_to_dbt(&key, NEXT_KEY_KEY),
72                      svn_fs_base__str_to_dbt(&value, "0"), 0));
73  }
74
75  *transactions_p = txns;
76  return 0;
77}
78
79
80svn_error_t *
81svn_fs_bdb__put_txn(svn_fs_t *fs,
82                    const transaction_t *txn,
83                    const char *txn_name,
84                    trail_t *trail,
85                    apr_pool_t *pool)
86{
87  base_fs_data_t *bfd = fs->fsap_data;
88  svn_skel_t *txn_skel;
89  DBT key, value;
90
91  /* Convert native type to skel. */
92  SVN_ERR(svn_fs_base__unparse_transaction_skel(&txn_skel, txn, pool));
93
94  /* Only in the context of this function do we know that the DB call
95     will not attempt to modify txn_name, so the cast belongs here.  */
96  svn_fs_base__str_to_dbt(&key, txn_name);
97  svn_fs_base__skel_to_dbt(&value, txn_skel, pool);
98  svn_fs_base__trail_debug(trail, "transactions", "put");
99  return BDB_WRAP(fs, N_("storing transaction record"),
100                  bfd->transactions->put(bfd->transactions, trail->db_txn,
101                                         &key, &value, 0));
102}
103
104
105/* Allocate a Subversion transaction ID in FS, as part of TRAIL.  Set
106   *ID_P to the new transaction ID, allocated in POOL.  */
107static svn_error_t *
108allocate_txn_id(const char **id_p,
109                svn_fs_t *fs,
110                trail_t *trail,
111                apr_pool_t *pool)
112{
113  base_fs_data_t *bfd = fs->fsap_data;
114  DBT query, result;
115  apr_size_t len;
116  char next_key[MAX_KEY_SIZE];
117  int db_err;
118
119  svn_fs_base__str_to_dbt(&query, NEXT_KEY_KEY);
120
121  /* Get the current value associated with the `next-key' key in the table.  */
122  svn_fs_base__trail_debug(trail, "transactions", "get");
123  SVN_ERR(BDB_WRAP(fs, N_("allocating new transaction ID (getting 'next-key')"),
124                   bfd->transactions->get(bfd->transactions, trail->db_txn,
125                                          &query,
126                                          svn_fs_base__result_dbt(&result),
127                                          0)));
128  svn_fs_base__track_dbt(&result, pool);
129
130  /* Set our return value. */
131  *id_p = apr_pstrmemdup(pool, result.data, result.size);
132
133  /* Bump to future key. */
134  len = result.size;
135  svn_fs_base__next_key(result.data, &len, next_key);
136  svn_fs_base__str_to_dbt(&query, NEXT_KEY_KEY);
137  svn_fs_base__str_to_dbt(&result, next_key);
138  svn_fs_base__trail_debug(trail, "transactions", "put");
139  db_err = bfd->transactions->put(bfd->transactions, trail->db_txn,
140                                  &query, &result, 0);
141
142  return BDB_WRAP(fs, N_("bumping next transaction key"), db_err);
143}
144
145
146svn_error_t *
147svn_fs_bdb__create_txn(const char **txn_name_p,
148                       svn_fs_t *fs,
149                       const svn_fs_id_t *root_id,
150                       trail_t *trail,
151                       apr_pool_t *pool)
152{
153  const char *txn_name;
154  transaction_t txn;
155
156  SVN_ERR(allocate_txn_id(&txn_name, fs, trail, pool));
157  txn.kind = transaction_kind_normal;
158  txn.root_id = root_id;
159  txn.base_id = root_id;
160  txn.proplist = NULL;
161  txn.copies = NULL;
162  txn.revision = SVN_INVALID_REVNUM;
163  SVN_ERR(svn_fs_bdb__put_txn(fs, &txn, txn_name, trail, pool));
164
165  *txn_name_p = txn_name;
166  return SVN_NO_ERROR;
167}
168
169
170svn_error_t *
171svn_fs_bdb__delete_txn(svn_fs_t *fs,
172                       const char *txn_name,
173                       trail_t *trail,
174                       apr_pool_t *pool)
175{
176  base_fs_data_t *bfd = fs->fsap_data;
177  DBT key;
178  transaction_t *txn;
179
180  /* Make sure TXN is dead. */
181  SVN_ERR(svn_fs_bdb__get_txn(&txn, fs, txn_name, trail, pool));
182  if (is_committed(txn))
183    return svn_fs_base__err_txn_not_mutable(fs, txn_name);
184
185  /* Delete the transaction from the `transactions' table. */
186  svn_fs_base__str_to_dbt(&key, txn_name);
187  svn_fs_base__trail_debug(trail, "transactions", "del");
188  return BDB_WRAP(fs, N_("deleting entry from 'transactions' table"),
189                  bfd->transactions->del(bfd->transactions,
190                                         trail->db_txn, &key, 0));
191}
192
193
194svn_error_t *
195svn_fs_bdb__get_txn(transaction_t **txn_p,
196                    svn_fs_t *fs,
197                    const char *txn_name,
198                    trail_t *trail,
199                    apr_pool_t *pool)
200{
201  base_fs_data_t *bfd = fs->fsap_data;
202  DBT key, value;
203  int db_err;
204  svn_skel_t *skel;
205  transaction_t *transaction;
206
207  /* Only in the context of this function do we know that the DB call
208     will not attempt to modify txn_name, so the cast belongs here.  */
209  svn_fs_base__trail_debug(trail, "transactions", "get");
210  db_err = bfd->transactions->get(bfd->transactions, trail->db_txn,
211                                  svn_fs_base__str_to_dbt(&key, txn_name),
212                                  svn_fs_base__result_dbt(&value),
213                                  0);
214  svn_fs_base__track_dbt(&value, pool);
215
216  if (db_err == DB_NOTFOUND)
217    return svn_fs_base__err_no_such_txn(fs, txn_name);
218  SVN_ERR(BDB_WRAP(fs, N_("reading transaction"), db_err));
219
220  /* Parse TRANSACTION skel */
221  skel = svn_skel__parse(value.data, value.size, pool);
222  if (! skel)
223    return svn_fs_base__err_corrupt_txn(fs, txn_name);
224
225  /* Convert skel to native type. */
226  SVN_ERR(svn_fs_base__parse_transaction_skel(&transaction, skel, pool));
227  *txn_p = transaction;
228  return SVN_NO_ERROR;
229}
230
231
232svn_error_t *
233svn_fs_bdb__get_txn_list(apr_array_header_t **names_p,
234                         svn_fs_t *fs,
235                         trail_t *trail,
236                         apr_pool_t *pool)
237{
238  base_fs_data_t *bfd = fs->fsap_data;
239  apr_size_t const next_key_key_len = strlen(NEXT_KEY_KEY);
240  apr_pool_t *subpool = svn_pool_create(pool);
241  apr_array_header_t *names;
242  DBC *cursor;
243  DBT key, value;
244  int db_err, db_c_err;
245
246  /* Allocate the initial names array */
247  names = apr_array_make(pool, 4, sizeof(const char *));
248
249  /* Create a database cursor to list the transaction names. */
250  svn_fs_base__trail_debug(trail, "transactions", "cursor");
251  SVN_ERR(BDB_WRAP(fs, N_("reading transaction list (opening cursor)"),
252                   bfd->transactions->cursor(bfd->transactions,
253                                             trail->db_txn, &cursor, 0)));
254
255  /* Build a null-terminated array of keys in the transactions table. */
256  for (db_err = svn_bdb_dbc_get(cursor,
257                                svn_fs_base__result_dbt(&key),
258                                svn_fs_base__result_dbt(&value),
259                                DB_FIRST);
260       db_err == 0;
261       db_err = svn_bdb_dbc_get(cursor,
262                                svn_fs_base__result_dbt(&key),
263                                svn_fs_base__result_dbt(&value),
264                                DB_NEXT))
265    {
266      transaction_t *txn;
267      svn_skel_t *txn_skel;
268      svn_error_t *err;
269
270      /* Clear the per-iteration subpool */
271      svn_pool_clear(subpool);
272
273      /* Track the memory alloc'd for fetching the key and value here
274         so that when the containing pool is cleared, this memory is
275         freed. */
276      svn_fs_base__track_dbt(&key, subpool);
277      svn_fs_base__track_dbt(&value, subpool);
278
279      /* Ignore the "next-key" key. */
280      if (key.size == next_key_key_len
281          && 0 == memcmp(key.data, NEXT_KEY_KEY, next_key_key_len))
282        continue;
283
284      /* Parse TRANSACTION skel */
285      txn_skel = svn_skel__parse(value.data, value.size, subpool);
286      if (! txn_skel)
287        {
288          svn_bdb_dbc_close(cursor);
289          return svn_fs_base__err_corrupt_txn
290            (fs, apr_pstrmemdup(pool, key.data, key.size));
291        }
292
293      /* Convert skel to native type. */
294      if ((err = svn_fs_base__parse_transaction_skel(&txn, txn_skel,
295                                                     subpool)))
296        {
297          svn_bdb_dbc_close(cursor);
298          return svn_error_trace(err);
299        }
300
301      /* If this is an immutable "committed" transaction, ignore it. */
302      if (is_committed(txn))
303        continue;
304
305      /* Add the transaction name to the NAMES array, duping it into POOL. */
306      APR_ARRAY_PUSH(names, const char *) = apr_pstrmemdup(pool, key.data,
307                                                           key.size);
308    }
309
310  /* Check for errors, but close the cursor first. */
311  db_c_err = svn_bdb_dbc_close(cursor);
312  if (db_err != DB_NOTFOUND)
313    {
314      SVN_ERR(BDB_WRAP(fs, N_("reading transaction list (listing keys)"),
315                       db_err));
316    }
317  SVN_ERR(BDB_WRAP(fs, N_("reading transaction list (closing cursor)"),
318                   db_c_err));
319
320  /* Destroy the per-iteration subpool */
321  svn_pool_destroy(subpool);
322
323  *names_p = names;
324  return SVN_NO_ERROR;
325}
326