source3/lib/serverid.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Implementation of a reliable server_exists()
   4    Copyright (C) Volker Lendecke 2010
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "serverid.h"
  22 #include "dbwrap.h"
  23
  24 struct serverid_key {
  25         pid_t pid;
  26 #ifdef CLUSTER_SUPPORT
  27         uint32_t vnn;
  28 #endif
  29 };
  30
  31 struct serverid_data {
  32         uint64_t unique_id;
  33         uint32_t msg_flags;
  34 };
  35
  36 bool serverid_parent_init(TALLOC_CTX *mem_ctx)
  37 {
  38         struct tdb_wrap *db;
  39
  40         /*
  41          * Open the tdb in the parent process (smbd) so that our
  42          * CLEAR_IF_FIRST optimization in tdb_reopen_all can properly
  43          * work.
  44          */
  45
  46         db = tdb_wrap_open(mem_ctx, lock_path("serverid.tdb"),
  47                            0, TDB_DEFAULT|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH, O_RDWR|O_CREAT,
  48                            0644);
  49         if (db == NULL) {
  50                 DEBUG(1, ("could not open serverid.tdb: %s\n",
  51                           strerror(errno)));
  52                 return false;
  53         }
  54         return true;
  55 }
  56
  57 static struct db_context *serverid_db(void)
  58 {
  59         static struct db_context *db;
  60
  61         if (db != NULL) {
  62                 return db;
  63         }
  64         db = db_open(NULL, lock_path("serverid.tdb"), 0,
  65                      TDB_DEFAULT|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH, O_RDWR|O_CREAT, 0644);
  66         return db;
  67 }
  68
  69 static void serverid_fill_key(const struct server_id *id,
  70                               struct serverid_key *key)
  71 {
  72         ZERO_STRUCTP(key);
  73         key->pid = id->pid;
  74 #ifdef CLUSTER_SUPPORT
  75         key->vnn = id->vnn;
  76 #endif
  77 }
  78
  79 bool serverid_register(const struct server_id id, uint32_t msg_flags)
  80 {
  81         struct db_context *db;
  82         struct serverid_key key;
  83         struct serverid_data data;
  84         struct db_record *rec;
  85         TDB_DATA tdbkey, tdbdata;
  86         NTSTATUS status;
  87         bool ret = false;
  88
  89         db = serverid_db();
  90         if (db == NULL) {
  91                 return false;
  92         }
  93
  94         serverid_fill_key(&id, &key);
  95         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
  96
  97         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
  98         if (rec == NULL) {
  99                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 100                 return false;
 101         }
 102
 103         ZERO_STRUCT(data);
 104         data.unique_id = id.unique_id;
 105         data.msg_flags = msg_flags;
 106
 107         tdbdata = make_tdb_data((uint8_t *)&data, sizeof(data));
 108         status = rec->store(rec, tdbdata, 0);
 109         if (!NT_STATUS_IS_OK(status)) {
 110                 DEBUG(1, ("Storing serverid.tdb record failed: %s\n",
 111                           nt_errstr(status)));
 112                 goto done;
 113         }
 114         ret = true;
 115 done:
 116         TALLOC_FREE(rec);
 117         return ret;
 118 }
 119
 120 bool serverid_register_msg_flags(const struct server_id id, bool do_reg,
 121                                  uint32_t msg_flags)
 122 {
 123         struct db_context *db;
 124         struct serverid_key key;
 125         struct serverid_data *data;
 126         struct db_record *rec;
 127         TDB_DATA tdbkey;
 128         NTSTATUS status;
 129         bool ret = false;
 130
 131         db = serverid_db();
 132         if (db == NULL) {
 133                 return false;
 134         }
 135
 136         serverid_fill_key(&id, &key);
 137         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 138
 139         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 140         if (rec == NULL) {
 141                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 142                 return false;
 143         }
 144
 145         if (rec->value.dsize != sizeof(struct serverid_data)) {
 146                 DEBUG(1, ("serverid record has unexpected size %d "
 147                           "(wanted %d)\n", (int)rec->value.dsize,
 148                           (int)sizeof(struct serverid_data)));
 149                 goto done;
 150         }
 151
 152         data = (struct serverid_data *)rec->value.dptr;
 153
 154         if (do_reg) {
 155                 data->msg_flags |= msg_flags;
 156         } else {
 157                 data->msg_flags &= ~msg_flags;
 158         }
 159
 160         status = rec->store(rec, rec->value, 0);
 161         if (!NT_STATUS_IS_OK(status)) {
 162                 DEBUG(1, ("Storing serverid.tdb record failed: %s\n",
 163                           nt_errstr(status)));
 164                 goto done;
 165         }
 166         ret = true;
 167 done:
 168         TALLOC_FREE(rec);
 169         return ret;
 170 }
 171
 172 bool serverid_deregister(struct server_id id)
 173 {
 174         struct db_context *db;
 175         struct serverid_key key;
 176         struct db_record *rec;
 177         TDB_DATA tdbkey;
 178         NTSTATUS status;
 179         bool ret = false;
 180
 181         db = serverid_db();
 182         if (db == NULL) {
 183                 return false;
 184         }
 185
 186         serverid_fill_key(&id, &key);
 187         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 188
 189         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 190         if (rec == NULL) {
 191                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 192                 return false;
 193         }
 194
 195         status = rec->delete_rec(rec);
 196         if (!NT_STATUS_IS_OK(status)) {
 197                 DEBUG(1, ("Deleting serverid.tdb record failed: %s\n",
 198                           nt_errstr(status)));
 199                 goto done;
 200         }
 201         ret = true;
 202 done:
 203         TALLOC_FREE(rec);
 204         return ret;
 205 }
 206
 207 struct serverid_exists_state {
 208         const struct server_id *id;
 209         bool exists;
 210 };
 211
 212 static int server_exists_parse(TDB_DATA key, TDB_DATA data, void *priv)
 213 {
 214         struct serverid_exists_state *state =
 215                 (struct serverid_exists_state *)priv;
 216
 217         if (data.dsize != sizeof(struct serverid_data)) {
 218                 return -1;
 219         }
 220
 221         /*
 222          * Use memcmp, not direct compare. data.dptr might not be
 223          * aligned.
 224          */
 225         state->exists = (memcmp(&state->id->unique_id, data.dptr,
 226                                 sizeof(state->id->unique_id)) == 0);
 227         return 0;
 228 }
 229
 230 bool serverid_exists(const struct server_id *id)
 231 {
 232         struct db_context *db;
 233         struct serverid_exists_state state;
 234         struct serverid_key key;
 235         TDB_DATA tdbkey;
 236
 237         db = serverid_db();
 238         if (db == NULL) {
 239                 return false;
 240         }
 241
 242         serverid_fill_key(id, &key);
 243         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 244
 245         state.id = id;
 246         state.exists = false;
 247
 248         if (db->parse_record(db, tdbkey, server_exists_parse, &state) == -1) {
 249                 return false;
 250         }
 251         return state.exists;
 252 }
 253
 254 static bool serverid_rec_parse(const struct db_record *rec,
 255                                struct server_id *id, uint32_t *msg_flags)
 256 {
 257         struct serverid_key key;
 258         struct serverid_data data;
 259
 260         if (rec->key.dsize != sizeof(key)) {
 261                 DEBUG(1, ("Found invalid key length %d in serverid.tdb\n",
 262                           (int)rec->key.dsize));
 263                 return false;
 264         }
 265         if (rec->value.dsize != sizeof(data)) {
 266                 DEBUG(1, ("Found invalid value length %d in serverid.tdb\n",
 267                           (int)rec->value.dsize));
 268                 return false;
 269         }
 270
 271         memcpy(&key, rec->key.dptr, sizeof(key));
 272         memcpy(&data, rec->value.dptr, sizeof(data));
 273
 274         id->pid = key.pid;
 275 #ifdef CLUSTER_SUPPORT
 276         id->vnn = key.vnn;
 277 #endif
 278         id->unique_id = data.unique_id;
 279         *msg_flags = data.msg_flags;
 280         return true;
 281 }
 282
 283 struct serverid_traverse_read_state {
 284         int (*fn)(const struct server_id *id, uint32_t msg_flags,
 285                   void *private_data);
 286         void *private_data;
 287 };
 288
 289 static int serverid_traverse_read_fn(struct db_record *rec, void *private_data)
 290 {
 291         struct serverid_traverse_read_state *state =
 292                 (struct serverid_traverse_read_state *)private_data;
 293         struct server_id id;
 294         uint32_t msg_flags;
 295
 296         if (!serverid_rec_parse(rec, &id, &msg_flags)) {
 297                 return 0;
 298         }
 299         return state->fn(&id, msg_flags,state->private_data);
 300 }
 301
 302 bool serverid_traverse_read(int (*fn)(const struct server_id *id,
 303                                       uint32_t msg_flags, void *private_data),
 304                             void *private_data)
 305 {
 306         struct db_context *db;
 307         struct serverid_traverse_read_state state;
 308
 309         db = serverid_db();
 310         if (db == NULL) {
 311                 return false;
 312         }
 313         state.fn = fn;
 314         state.private_data = private_data;
 315         return db->traverse_read(db, serverid_traverse_read_fn, &state);
 316 }
 317
 318 struct serverid_traverse_state {
 319         int (*fn)(struct db_record *rec, const struct server_id *id,
 320                   uint32_t msg_flags, void *private_data);
 321         void *private_data;
 322 };
 323
 324 static int serverid_traverse_fn(struct db_record *rec, void *private_data)
 325 {
 326         struct serverid_traverse_state *state =
 327                 (struct serverid_traverse_state *)private_data;
 328         struct server_id id;
 329         uint32_t msg_flags;
 330
 331         if (!serverid_rec_parse(rec, &id, &msg_flags)) {
 332                 return 0;
 333         }
 334         return state->fn(rec, &id, msg_flags, state->private_data);
 335 }
 336
 337 bool serverid_traverse(int (*fn)(struct db_record *rec,
 338                                  const struct server_id *id,
 339                                  uint32_t msg_flags, void *private_data),
 340                             void *private_data)
 341 {
 342         struct db_context *db;
 343         struct serverid_traverse_state state;
 344
 345         db = serverid_db();
 346         if (db == NULL) {
 347                 return false;
 348         }
 349         state.fn = fn;
 350         state.private_data = private_data;
 351         return db->traverse(db, serverid_traverse_fn, &state);
 352 }