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 "system/filesys.h"
  22 #include "serverid.h"
  23 #include "util_tdb.h"
  24 #include "dbwrap.h"
  25 #include "lib/util/tdb_wrap.h"
  26
  27 struct serverid_key {
  28         pid_t pid;
  29         uint32_t vnn;
  30 };
  31
  32 struct serverid_data {
  33         uint64_t unique_id;
  34         uint32_t msg_flags;
  35 };
  36
  37 bool serverid_parent_init(TALLOC_CTX *mem_ctx)
  38 {
  39         struct tdb_wrap *db;
  40
  41         /*
  42          * Open the tdb in the parent process (smbd) so that our
  43          * CLEAR_IF_FIRST optimization in tdb_reopen_all can properly
  44          * work.
  45          */
  46
  47         db = tdb_wrap_open(mem_ctx, lock_path("serverid.tdb"),
  48                            0, TDB_DEFAULT|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH, O_RDWR|O_CREAT,
  49                            0644);
  50         if (db == NULL) {
  51                 DEBUG(1, ("could not open serverid.tdb: %s\n",
  52                           strerror(errno)));
  53                 return false;
  54         }
  55         return true;
  56 }
  57
  58 static struct db_context *serverid_db(void)
  59 {
  60         static struct db_context *db;
  61
  62         if (db != NULL) {
  63                 return db;
  64         }
  65         db = db_open(NULL, lock_path("serverid.tdb"), 0,
  66                      TDB_DEFAULT|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH, O_RDWR|O_CREAT, 0644);
  67         return db;
  68 }
  69
  70 static void serverid_fill_key(const struct server_id *id,
  71                               struct serverid_key *key)
  72 {
  73         ZERO_STRUCTP(key);
  74         key->pid = id->pid;
  75         key->vnn = id->vnn;
  76 }
  77
  78 bool serverid_register(const struct server_id id, uint32_t msg_flags)
  79 {
  80         struct db_context *db;
  81         struct serverid_key key;
  82         struct serverid_data data;
  83         struct db_record *rec;
  84         TDB_DATA tdbkey, tdbdata;
  85         NTSTATUS status;
  86         bool ret = false;
  87
  88         db = serverid_db();
  89         if (db == NULL) {
  90                 return false;
  91         }
  92
  93         serverid_fill_key(&id, &key);
  94         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
  95
  96         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
  97         if (rec == NULL) {
  98                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
  99                 return false;
 100         }
 101
 102         ZERO_STRUCT(data);
 103         data.unique_id = id.unique_id;
 104         data.msg_flags = msg_flags;
 105
 106         tdbdata = make_tdb_data((uint8_t *)&data, sizeof(data));
 107         status = rec->store(rec, tdbdata, 0);
 108         if (!NT_STATUS_IS_OK(status)) {
 109                 DEBUG(1, ("Storing serverid.tdb record failed: %s\n",
 110                           nt_errstr(status)));
 111                 goto done;
 112         }
 113         ret = true;
 114 done:
 115         TALLOC_FREE(rec);
 116         return ret;
 117 }
 118
 119 bool serverid_register_msg_flags(const struct server_id id, bool do_reg,
 120                                  uint32_t msg_flags)
 121 {
 122         struct db_context *db;
 123         struct serverid_key key;
 124         struct serverid_data *data;
 125         struct db_record *rec;
 126         TDB_DATA tdbkey;
 127         NTSTATUS status;
 128         bool ret = false;
 129
 130         db = serverid_db();
 131         if (db == NULL) {
 132                 return false;
 133         }
 134
 135         serverid_fill_key(&id, &key);
 136         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 137
 138         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 139         if (rec == NULL) {
 140                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 141                 return false;
 142         }
 143
 144         if (rec->value.dsize != sizeof(struct serverid_data)) {
 145                 DEBUG(1, ("serverid record has unexpected size %d "
 146                           "(wanted %d)\n", (int)rec->value.dsize,
 147                           (int)sizeof(struct serverid_data)));
 148                 goto done;
 149         }
 150
 151         data = (struct serverid_data *)rec->value.dptr;
 152
 153         if (do_reg) {
 154                 data->msg_flags |= msg_flags;
 155         } else {
 156                 data->msg_flags &= ~msg_flags;
 157         }
 158
 159         status = rec->store(rec, rec->value, 0);
 160         if (!NT_STATUS_IS_OK(status)) {
 161                 DEBUG(1, ("Storing serverid.tdb record failed: %s\n",
 162                           nt_errstr(status)));
 163                 goto done;
 164         }
 165         ret = true;
 166 done:
 167         TALLOC_FREE(rec);
 168         return ret;
 169 }
 170
 171 bool serverid_deregister(struct server_id id)
 172 {
 173         struct db_context *db;
 174         struct serverid_key key;
 175         struct db_record *rec;
 176         TDB_DATA tdbkey;
 177         NTSTATUS status;
 178         bool ret = false;
 179
 180         db = serverid_db();
 181         if (db == NULL) {
 182                 return false;
 183         }
 184
 185         serverid_fill_key(&id, &key);
 186         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 187
 188         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 189         if (rec == NULL) {
 190                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 191                 return false;
 192         }
 193
 194         status = rec->delete_rec(rec);
 195         if (!NT_STATUS_IS_OK(status)) {
 196                 DEBUG(1, ("Deleting serverid.tdb record failed: %s\n",
 197                           nt_errstr(status)));
 198                 goto done;
 199         }
 200         ret = true;
 201 done:
 202         TALLOC_FREE(rec);
 203         return ret;
 204 }
 205
 206 struct serverid_exists_state {
 207         const struct server_id *id;
 208         bool exists;
 209 };
 210
 211 static int server_exists_parse(TDB_DATA key, TDB_DATA data, void *priv)
 212 {
 213         struct serverid_exists_state *state =
 214                 (struct serverid_exists_state *)priv;
 215
 216         if (data.dsize != sizeof(struct serverid_data)) {
 217                 return -1;
 218         }
 219
 220         /*
 221          * Use memcmp, not direct compare. data.dptr might not be
 222          * aligned.
 223          */
 224         state->exists = (memcmp(&state->id->unique_id, data.dptr,
 225                                 sizeof(state->id->unique_id)) == 0);
 226         return 0;
 227 }
 228
 229 bool serverid_exists(const struct server_id *id)
 230 {
 231         struct db_context *db;
 232         struct serverid_exists_state state;
 233         struct serverid_key key;
 234         TDB_DATA tdbkey;
 235
 236         if (procid_is_me(id)) {
 237                 return true;
 238         }
 239
 240         if (!process_exists(*id)) {
 241                 return false;
 242         }
 243
 244         if (id->unique_id == SERVERID_UNIQUE_ID_NOT_TO_VERIFY) {
 245                 return true;
 246         }
 247
 248         db = serverid_db();
 249         if (db == NULL) {
 250                 return false;
 251         }
 252
 253         serverid_fill_key(id, &key);
 254         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 255
 256         state.id = id;
 257         state.exists = false;
 258
 259         if (db->parse_record(db, tdbkey, server_exists_parse, &state) == -1) {
 260                 return false;
 261         }
 262         return state.exists;
 263 }
 264
 265 static bool serverid_rec_parse(const struct db_record *rec,
 266                                struct server_id *id, uint32_t *msg_flags)
 267 {
 268         struct serverid_key key;
 269         struct serverid_data data;
 270
 271         if (rec->key.dsize != sizeof(key)) {
 272                 DEBUG(1, ("Found invalid key length %d in serverid.tdb\n",
 273                           (int)rec->key.dsize));
 274                 return false;
 275         }
 276         if (rec->value.dsize != sizeof(data)) {
 277                 DEBUG(1, ("Found invalid value length %d in serverid.tdb\n",
 278                           (int)rec->value.dsize));
 279                 return false;
 280         }
 281
 282         memcpy(&key, rec->key.dptr, sizeof(key));
 283         memcpy(&data, rec->value.dptr, sizeof(data));
 284
 285         id->pid = key.pid;
 286         id->vnn = key.vnn;
 287         id->unique_id = data.unique_id;
 288         *msg_flags = data.msg_flags;
 289         return true;
 290 }
 291
 292 struct serverid_traverse_read_state {
 293         int (*fn)(const struct server_id *id, uint32_t msg_flags,
 294                   void *private_data);
 295         void *private_data;
 296 };
 297
 298 static int serverid_traverse_read_fn(struct db_record *rec, void *private_data)
 299 {
 300         struct serverid_traverse_read_state *state =
 301                 (struct serverid_traverse_read_state *)private_data;
 302         struct server_id id;
 303         uint32_t msg_flags;
 304
 305         if (!serverid_rec_parse(rec, &id, &msg_flags)) {
 306                 return 0;
 307         }
 308         return state->fn(&id, msg_flags,state->private_data);
 309 }
 310
 311 bool serverid_traverse_read(int (*fn)(const struct server_id *id,
 312                                       uint32_t msg_flags, void *private_data),
 313                             void *private_data)
 314 {
 315         struct db_context *db;
 316         struct serverid_traverse_read_state state;
 317
 318         db = serverid_db();
 319         if (db == NULL) {
 320                 return false;
 321         }
 322         state.fn = fn;
 323         state.private_data = private_data;
 324         return db->traverse_read(db, serverid_traverse_read_fn, &state);
 325 }
 326
 327 struct serverid_traverse_state {
 328         int (*fn)(struct db_record *rec, const struct server_id *id,
 329                   uint32_t msg_flags, void *private_data);
 330         void *private_data;
 331 };
 332
 333 static int serverid_traverse_fn(struct db_record *rec, void *private_data)
 334 {
 335         struct serverid_traverse_state *state =
 336                 (struct serverid_traverse_state *)private_data;
 337         struct server_id id;
 338         uint32_t msg_flags;
 339
 340         if (!serverid_rec_parse(rec, &id, &msg_flags)) {
 341                 return 0;
 342         }
 343         return state->fn(rec, &id, msg_flags, state->private_data);
 344 }
 345
 346 bool serverid_traverse(int (*fn)(struct db_record *rec,
 347                                  const struct server_id *id,
 348                                  uint32_t msg_flags, void *private_data),
 349                             void *private_data)
 350 {
 351         struct db_context *db;
 352         struct serverid_traverse_state state;
 353
 354         db = serverid_db();
 355         if (db == NULL) {
 356                 return false;
 357         }
 358         state.fn = fn;
 359         state.private_data = private_data;
 360         return db->traverse(db, serverid_traverse_fn, &state);
 361 }
 362
 363 uint64_t serverid_get_random_unique_id(void)
 364 {
 365         uint64_t unique_id = SERVERID_UNIQUE_ID_NOT_TO_VERIFY;
 366
 367         while (unique_id == SERVERID_UNIQUE_ID_NOT_TO_VERIFY) {
 368                 generate_random_buffer((uint8_t *)&unique_id,
 369                                         sizeof(unique_id));
 370         }
 371
 372         return unique_id;
 373 }