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/dbwrap.h"
  25 #include "dbwrap/dbwrap_open.h"
  26 #include "lib/util/tdb_wrap.h"
  27
  28 struct serverid_key {
  29         pid_t pid;
  30         uint32_t task_id;
  31         uint32_t vnn;
  32 };
  33
  34 struct serverid_data {
  35         uint64_t unique_id;
  36         uint32_t msg_flags;
  37 };
  38
  39 bool serverid_parent_init(TALLOC_CTX *mem_ctx)
  40 {
  41         struct tdb_wrap *db;
  42
  43         /*
  44          * Open the tdb in the parent process (smbd) so that our
  45          * CLEAR_IF_FIRST optimization in tdb_reopen_all can properly
  46          * work.
  47          */
  48
  49         db = tdb_wrap_open(mem_ctx, lock_path("serverid.tdb"),
  50                            0, TDB_DEFAULT|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH, O_RDWR|O_CREAT,
  51                            0644);
  52         if (db == NULL) {
  53                 DEBUG(1, ("could not open serverid.tdb: %s\n",
  54                           strerror(errno)));
  55                 return false;
  56         }
  57         return true;
  58 }
  59
  60 static struct db_context *serverid_db(void)
  61 {
  62         static struct db_context *db;
  63
  64         if (db != NULL) {
  65                 return db;
  66         }
  67         db = db_open(NULL, lock_path("serverid.tdb"), 0,
  68                      TDB_DEFAULT|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH, O_RDWR|O_CREAT, 0644);
  69         return db;
  70 }
  71
  72 static void serverid_fill_key(const struct server_id *id,
  73                               struct serverid_key *key)
  74 {
  75         ZERO_STRUCTP(key);
  76         key->pid = id->pid;
  77         key->task_id = id->task_id;
  78         key->vnn = id->vnn;
  79 }
  80
  81 bool serverid_register(const struct server_id id, uint32_t msg_flags)
  82 {
  83         struct db_context *db;
  84         struct serverid_key key;
  85         struct serverid_data data;
  86         struct db_record *rec;
  87         TDB_DATA tdbkey, tdbdata;
  88         NTSTATUS status;
  89         bool ret = false;
  90
  91         db = serverid_db();
  92         if (db == NULL) {
  93                 return false;
  94         }
  95
  96         serverid_fill_key(&id, &key);
  97         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
  98
  99         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 100         if (rec == NULL) {
 101                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 102                 return false;
 103         }
 104
 105         ZERO_STRUCT(data);
 106         data.unique_id = id.unique_id;
 107         data.msg_flags = msg_flags;
 108
 109         tdbdata = make_tdb_data((uint8_t *)&data, sizeof(data));
 110         status = rec->store(rec, tdbdata, 0);
 111         if (!NT_STATUS_IS_OK(status)) {
 112                 DEBUG(1, ("Storing serverid.tdb record failed: %s\n",
 113                           nt_errstr(status)));
 114                 goto done;
 115         }
 116         ret = true;
 117 done:
 118         TALLOC_FREE(rec);
 119         return ret;
 120 }
 121
 122 bool serverid_register_msg_flags(const struct server_id id, bool do_reg,
 123                                  uint32_t msg_flags)
 124 {
 125         struct db_context *db;
 126         struct serverid_key key;
 127         struct serverid_data *data;
 128         struct db_record *rec;
 129         TDB_DATA tdbkey;
 130         NTSTATUS status;
 131         bool ret = false;
 132
 133         db = serverid_db();
 134         if (db == NULL) {
 135                 return false;
 136         }
 137
 138         serverid_fill_key(&id, &key);
 139         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 140
 141         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 142         if (rec == NULL) {
 143                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 144                 return false;
 145         }
 146
 147         if (rec->value.dsize != sizeof(struct serverid_data)) {
 148                 DEBUG(1, ("serverid record has unexpected size %d "
 149                           "(wanted %d)\n", (int)rec->value.dsize,
 150                           (int)sizeof(struct serverid_data)));
 151                 goto done;
 152         }
 153
 154         data = (struct serverid_data *)rec->value.dptr;
 155
 156         if (do_reg) {
 157                 data->msg_flags |= msg_flags;
 158         } else {
 159                 data->msg_flags &= ~msg_flags;
 160         }
 161
 162         status = rec->store(rec, rec->value, 0);
 163         if (!NT_STATUS_IS_OK(status)) {
 164                 DEBUG(1, ("Storing serverid.tdb record failed: %s\n",
 165                           nt_errstr(status)));
 166                 goto done;
 167         }
 168         ret = true;
 169 done:
 170         TALLOC_FREE(rec);
 171         return ret;
 172 }
 173
 174 bool serverid_deregister(struct server_id id)
 175 {
 176         struct db_context *db;
 177         struct serverid_key key;
 178         struct db_record *rec;
 179         TDB_DATA tdbkey;
 180         NTSTATUS status;
 181         bool ret = false;
 182
 183         db = serverid_db();
 184         if (db == NULL) {
 185                 return false;
 186         }
 187
 188         serverid_fill_key(&id, &key);
 189         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 190
 191         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 192         if (rec == NULL) {
 193                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 194                 return false;
 195         }
 196
 197         status = rec->delete_rec(rec);
 198         if (!NT_STATUS_IS_OK(status)) {
 199                 DEBUG(1, ("Deleting serverid.tdb record failed: %s\n",
 200                           nt_errstr(status)));
 201                 goto done;
 202         }
 203         ret = true;
 204 done:
 205         TALLOC_FREE(rec);
 206         return ret;
 207 }
 208
 209 struct serverid_exists_state {
 210         const struct server_id *id;
 211         bool exists;
 212 };
 213
 214 static int server_exists_parse(TDB_DATA key, TDB_DATA data, void *priv)
 215 {
 216         struct serverid_exists_state *state =
 217                 (struct serverid_exists_state *)priv;
 218
 219         if (data.dsize != sizeof(struct serverid_data)) {
 220                 return -1;
 221         }
 222
 223         /*
 224          * Use memcmp, not direct compare. data.dptr might not be
 225          * aligned.
 226          */
 227         state->exists = (memcmp(&state->id->unique_id, data.dptr,
 228                                 sizeof(state->id->unique_id)) == 0);
 229         return 0;
 230 }
 231
 232 bool serverid_exists(const struct server_id *id)
 233 {
 234         struct db_context *db;
 235         struct serverid_exists_state state;
 236         struct serverid_key key;
 237         TDB_DATA tdbkey;
 238
 239         if (procid_is_me(id)) {
 240                 return true;
 241         }
 242
 243         if (!process_exists(*id)) {
 244                 return false;
 245         }
 246
 247         db = serverid_db();
 248         if (db == NULL) {
 249                 return false;
 250         }
 251
 252         serverid_fill_key(id, &key);
 253         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 254
 255         state.id = id;
 256         state.exists = false;
 257
 258         if (db->parse_record(db, tdbkey, server_exists_parse, &state) != 0) {
 259                 return false;
 260         }
 261         return state.exists;
 262 }
 263
 264 static bool serverid_rec_parse(const struct db_record *rec,
 265                                struct server_id *id, uint32_t *msg_flags)
 266 {
 267         struct serverid_key key;
 268         struct serverid_data data;
 269
 270         if (rec->key.dsize != sizeof(key)) {
 271                 DEBUG(1, ("Found invalid key length %d in serverid.tdb\n",
 272                           (int)rec->key.dsize));
 273                 return false;
 274         }
 275         if (rec->value.dsize != sizeof(data)) {
 276                 DEBUG(1, ("Found invalid value length %d in serverid.tdb\n",
 277                           (int)rec->value.dsize));
 278                 return false;
 279         }
 280
 281         memcpy(&key, rec->key.dptr, sizeof(key));
 282         memcpy(&data, rec->value.dptr, sizeof(data));
 283
 284         id->pid = key.pid;
 285         id->task_id = key.task_id;
 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 }