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
  23 struct serverid_key {
  24         pid_t pid;
  25 #ifdef CLUSTER_SUPPORT
  26         uint32_t vnn;
  27 #endif
  28 };
  29
  30 bool serverid_parent_init(void)
  31 {
  32         struct tdb_wrap *db;
  33
  34         /*
  35          * Open the tdb in the parent process (smbd) so that our
  36          * CLEAR_IF_FIRST optimization in tdb_reopen_all can properly
  37          * work.
  38          */
  39
  40         db = tdb_wrap_open(talloc_autofree_context(),
  41                            lock_path("serverid.tdb"),
  42                            0, TDB_DEFAULT|TDB_CLEAR_IF_FIRST, O_RDWR|O_CREAT,
  43                            0644);
  44         if (db == NULL) {
  45                 DEBUG(1, ("could not open serverid.tdb: %s\n",
  46                           strerror(errno)));
  47                 return false;
  48         }
  49         return true;
  50 }
  51
  52 struct serverid_data {
  53         uint64_t unique_id;
  54         uint32_t msg_flags;
  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(talloc_autofree_context(), lock_path("serverid.tdb"),
  65                      0, TDB_DEFAULT|TDB_CLEAR_IF_FIRST, 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_self(uint32_t msg_flags)
 121 {
 122         struct server_id pid;
 123
 124         pid = procid_self();
 125         return serverid_register(&pid, msg_flags);
 126 }
 127
 128 bool serverid_deregister(const struct server_id *id)
 129 {
 130         struct db_context *db;
 131         struct serverid_key key;
 132         struct db_record *rec;
 133         TDB_DATA tdbkey;
 134         NTSTATUS status;
 135         bool ret = false;
 136
 137         db = serverid_db();
 138         if (db == NULL) {
 139                 return false;
 140         }
 141
 142         serverid_fill_key(id, &key);
 143         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 144
 145         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 146         if (rec == NULL) {
 147                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 148                 return false;
 149         }
 150
 151         status = rec->delete_rec(rec);
 152         if (!NT_STATUS_IS_OK(status)) {
 153                 DEBUG(1, ("Deleting serverid.tdb record failed: %s\n",
 154                           nt_errstr(status)));
 155                 goto done;
 156         }
 157         ret = true;
 158 done:
 159         TALLOC_FREE(rec);
 160         return ret;
 161 }
 162
 163 bool serverid_deregister_self(void)
 164 {
 165         struct server_id pid;
 166
 167         pid = procid_self();
 168         return serverid_deregister(&pid);
 169 }
 170
 171 struct serverid_exists_state {
 172         const struct server_id *id;
 173         bool exists;
 174 };
 175
 176 static int server_exists_parse(TDB_DATA key, TDB_DATA data, void *priv)
 177 {
 178         struct serverid_exists_state *state =
 179                 (struct serverid_exists_state *)priv;
 180         uint64_t unique_id;
 181
 182         if (data.dsize != sizeof(struct serverid_data)) {
 183                 return -1;
 184         }
 185
 186         /* memcpy, data.dptr might not be aligned */
 187         memcpy(&unique_id, data.dptr, sizeof(unique_id));
 188
 189         state->exists = (state->id->unique_id == unique_id);
 190         return 0;
 191 }
 192
 193 bool serverid_exists(const struct server_id *id)
 194 {
 195         struct db_context *db;
 196         struct serverid_exists_state state;
 197         struct serverid_key key;
 198         TDB_DATA tdbkey;
 199
 200         db = serverid_db();
 201         if (db == NULL) {
 202                 return false;
 203         }
 204
 205         serverid_fill_key(id, &key);
 206         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 207
 208         state.id = id;
 209         state.exists = false;
 210
 211         if (db->parse_record(db, tdbkey, server_exists_parse, &state) == -1) {
 212                 return false;
 213         }
 214         return state.exists;
 215 }
 216
 217 static bool serverid_rec_parse(const struct db_record *rec,
 218                                struct server_id *id, uint32_t *msg_flags)
 219 {
 220         struct serverid_key key;
 221         struct serverid_data data;
 222
 223         if (rec->key.dsize != sizeof(key)) {
 224                 DEBUG(1, ("Found invalid key length %d in serverid.tdb\n",
 225                           (int)rec->key.dsize));
 226                 return false;
 227         }
 228         if (rec->value.dsize != sizeof(data)) {
 229                 DEBUG(1, ("Found invalid value length %d in serverid.tdb\n",
 230                           (int)rec->value.dsize));
 231                 return false;
 232         }
 233
 234         memcpy(&key, rec->key.dptr, sizeof(key));
 235         memcpy(&data, rec->value.dptr, sizeof(data));
 236
 237         id->pid = key.pid;
 238 #ifdef CLUSTER_SUPPORT
 239         id->vnn = key.vnn;
 240 #endif
 241         id->unique_id = data.unique_id;
 242         *msg_flags = data.msg_flags;
 243         return true;
 244 }
 245
 246 struct serverid_traverse_read_state {
 247         int (*fn)(const struct server_id *id, uint32_t msg_flags,
 248                   void *private_data);
 249         void *private_data;
 250 };
 251
 252 static int serverid_traverse_read_fn(struct db_record *rec, void *private_data)
 253 {
 254         struct serverid_traverse_read_state *state =
 255                 (struct serverid_traverse_read_state *)private_data;
 256         struct server_id id;
 257         uint32_t msg_flags;
 258
 259         if (!serverid_rec_parse(rec, &id, &msg_flags)) {
 260                 return 0;
 261         }
 262         return state->fn(&id, msg_flags,state->private_data);
 263 }
 264
 265 bool serverid_traverse_read(int (*fn)(const struct server_id *id,
 266                                       uint32_t msg_flags, void *private_data),
 267                             void *private_data)
 268 {
 269         struct db_context *db;
 270         struct serverid_traverse_read_state state;
 271
 272         db = serverid_db();
 273         if (db == NULL) {
 274                 return false;
 275         }
 276         state.fn = fn;
 277         state.private_data = private_data;
 278         return db->traverse_read(db, serverid_traverse_read_fn, &state);
 279 }
 280
 281 struct serverid_traverse_state {
 282         int (*fn)(struct db_record *rec, const struct server_id *id,
 283                   uint32_t msg_flags, void *private_data);
 284         void *private_data;
 285 };
 286
 287 static int serverid_traverse_fn(struct db_record *rec, void *private_data)
 288 {
 289         struct serverid_traverse_state *state =
 290                 (struct serverid_traverse_state *)private_data;
 291         struct server_id id;
 292         uint32_t msg_flags;
 293
 294         if (!serverid_rec_parse(rec, &id, &msg_flags)) {
 295                 return 0;
 296         }
 297         return state->fn(rec, &id, msg_flags, state->private_data);
 298 }
 299
 300 bool serverid_traverse(int (*fn)(struct db_record *rec,
 301                                  const struct server_id *id,
 302                                  uint32_t msg_flags, void *private_data),
 303                             void *private_data)
 304 {
 305         struct db_context *db;
 306         struct serverid_traverse_state state;
 307
 308         db = serverid_db();
 309         if (db == NULL) {
 310                 return false;
 311         }
 312         state.fn = fn;
 313         state.private_data = private_data;
 314         return db->traverse(db, serverid_traverse_fn, &state);
 315 }