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 struct serverid_data {
  31         uint64_t unique_id;
  32         uint32_t msg_flags;
  33 };
  34
  35 static struct db_context *serverid_db(void)
  36 {
  37         static struct db_context *db;
  38
  39         if (db != NULL) {
  40                 return db;
  41         }
  42         db = db_open(talloc_autofree_context(), lock_path("serverid.tdb"),
  43                      0, TDB_DEFAULT|TDB_CLEAR_IF_FIRST, O_RDWR|O_CREAT, 0644);
  44         return db;
  45 }
  46
  47 static void serverid_fill_key(const struct server_id *id,
  48                               struct serverid_key *key)
  49 {
  50         ZERO_STRUCTP(key);
  51         key->pid = id->pid;
  52 #ifdef CLUSTER_SUPPORT
  53         key->vnn = id->vnn;
  54 #endif
  55 }
  56
  57 bool serverid_register(const struct server_id *id, uint32_t msg_flags)
  58 {
  59         struct db_context *db;
  60         struct serverid_key key;
  61         struct serverid_data data;
  62         struct db_record *rec;
  63         TDB_DATA tdbkey, tdbdata;
  64         NTSTATUS status;
  65         bool ret = false;
  66
  67         db = serverid_db();
  68         if (db == NULL) {
  69                 return false;
  70         }
  71
  72         serverid_fill_key(id, &key);
  73         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
  74
  75         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
  76         if (rec == NULL) {
  77                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
  78                 return false;
  79         }
  80
  81         ZERO_STRUCT(data);
  82         data.unique_id = id->unique_id;
  83         data.msg_flags = msg_flags;
  84
  85         tdbdata = make_tdb_data((uint8_t *)&data, sizeof(data));
  86         status = rec->store(rec, tdbdata, 0);
  87         if (!NT_STATUS_IS_OK(status)) {
  88                 DEBUG(1, ("Storing serverid.tdb record failed: %s\n",
  89                           nt_errstr(status)));
  90                 goto done;
  91         }
  92         ret = true;
  93 done:
  94         TALLOC_FREE(rec);
  95         return ret;
  96 }
  97
  98 bool serverid_register_self(uint32_t msg_flags)
  99 {
 100         struct server_id pid;
 101
 102         pid = procid_self();
 103         return serverid_register(&pid, msg_flags);
 104 }
 105
 106 bool serverid_deregister(const struct server_id *id)
 107 {
 108         struct db_context *db;
 109         struct serverid_key key;
 110         struct db_record *rec;
 111         TDB_DATA tdbkey;
 112         NTSTATUS status;
 113         bool ret = false;
 114
 115         db = serverid_db();
 116         if (db == NULL) {
 117                 return false;
 118         }
 119
 120         serverid_fill_key(id, &key);
 121         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 122
 123         rec = db->fetch_locked(db, talloc_tos(), tdbkey);
 124         if (rec == NULL) {
 125                 DEBUG(1, ("Could not fetch_lock serverid.tdb record\n"));
 126                 return false;
 127         }
 128
 129         status = rec->delete_rec(rec);
 130         if (!NT_STATUS_IS_OK(status)) {
 131                 DEBUG(1, ("Deleting serverid.tdb record failed: %s\n",
 132                           nt_errstr(status)));
 133                 goto done;
 134         }
 135         ret = true;
 136 done:
 137         TALLOC_FREE(rec);
 138         return ret;
 139 }
 140
 141 bool serverid_deregister_self(void)
 142 {
 143         struct server_id pid;
 144
 145         pid = procid_self();
 146         return serverid_deregister(&pid);
 147 }
 148
 149 struct serverid_exists_state {
 150         const struct server_id *id;
 151         bool exists;
 152 };
 153
 154 static int server_exists_parse(TDB_DATA key, TDB_DATA data, void *priv)
 155 {
 156         struct serverid_exists_state *state =
 157                 (struct serverid_exists_state *)priv;
 158         uint64_t unique_id;
 159
 160         if (data.dsize != sizeof(struct serverid_data)) {
 161                 return -1;
 162         }
 163
 164         /* memcpy, data.dptr might not be aligned */
 165         memcpy(&unique_id, data.dptr, sizeof(unique_id));
 166
 167         state->exists = (state->id->unique_id == unique_id);
 168         return 0;
 169 }
 170
 171 bool serverid_exists(const struct server_id *id)
 172 {
 173         struct db_context *db;
 174         struct serverid_exists_state state;
 175         struct serverid_key key;
 176         TDB_DATA tdbkey;
 177
 178         db = serverid_db();
 179         if (db == NULL) {
 180                 return false;
 181         }
 182
 183         serverid_fill_key(id, &key);
 184         tdbkey = make_tdb_data((uint8_t *)&key, sizeof(key));
 185
 186         state.id = id;
 187         state.exists = false;
 188
 189         if (db->parse_record(db, tdbkey, server_exists_parse, &state) == -1) {
 190                 return false;
 191         }
 192         return state.exists;
 193 }
 194
 195 static bool serverid_rec_parse(const struct db_record *rec,
 196                                struct server_id *id, uint32_t *msg_flags)
 197 {
 198         struct serverid_key key;
 199         struct serverid_data data;
 200
 201         if (rec->key.dsize != sizeof(key)) {
 202                 DEBUG(1, ("Found invalid key length %d in serverid.tdb\n",
 203                           (int)rec->key.dsize));
 204                 return false;
 205         }
 206         if (rec->value.dsize != sizeof(data)) {
 207                 DEBUG(1, ("Found invalid value length %d in serverid.tdb\n",
 208                           (int)rec->value.dsize));
 209                 return false;
 210         }
 211
 212         memcpy(&key, rec->key.dptr, sizeof(key));
 213         memcpy(&data, rec->value.dptr, sizeof(data));
 214
 215         id->pid = key.pid;
 216 #ifdef CLUSTER_SUPPORT
 217         id->vnn = key.vnn;
 218 #endif
 219         id->unique_id = data.unique_id;
 220         *msg_flags = data.msg_flags;
 221         return true;
 222 }
 223
 224 struct serverid_traverse_read_state {
 225         int (*fn)(const struct server_id *id, uint32_t msg_flags,
 226                   void *private_data);
 227         void *private_data;
 228 };
 229
 230 static int serverid_traverse_read_fn(struct db_record *rec, void *private_data)
 231 {
 232         struct serverid_traverse_read_state *state =
 233                 (struct serverid_traverse_read_state *)private_data;
 234         struct server_id id;
 235         uint32_t msg_flags;
 236
 237         if (!serverid_rec_parse(rec, &id, &msg_flags)) {
 238                 return 0;
 239         }
 240         return state->fn(&id, msg_flags,state->private_data);
 241 }
 242
 243 bool serverid_traverse_read(int (*fn)(const struct server_id *id,
 244                                       uint32_t msg_flags, void *private_data),
 245                             void *private_data)
 246 {
 247         struct db_context *db;
 248         struct serverid_traverse_read_state state;
 249
 250         db = serverid_db();
 251         if (db == NULL) {
 252                 return false;
 253         }
 254         state.fn = fn;
 255         state.private_data = private_data;
 256         return db->traverse_read(db, serverid_traverse_read_fn, &state);
 257 }
 258
 259 struct serverid_traverse_state {
 260         int (*fn)(struct db_record *rec, const struct server_id *id,
 261                   uint32_t msg_flags, void *private_data);
 262         void *private_data;
 263 };
 264
 265 static int serverid_traverse_fn(struct db_record *rec, void *private_data)
 266 {
 267         struct serverid_traverse_state *state =
 268                 (struct serverid_traverse_state *)private_data;
 269         struct server_id id;
 270         uint32_t msg_flags;
 271
 272         if (!serverid_rec_parse(rec, &id, &msg_flags)) {
 273                 return 0;
 274         }
 275         return state->fn(rec, &id, msg_flags, state->private_data);
 276 }
 277
 278 bool serverid_traverse(int (*fn)(struct db_record *rec,
 279                                  const struct server_id *id,
 280                                  uint32_t msg_flags, void *private_data),
 281                             void *private_data)
 282 {
 283         struct db_context *db;
 284         struct serverid_traverse_state state;
 285
 286         db = serverid_db();
 287         if (db == NULL) {
 288                 return false;
 289         }
 290         state.fn = fn;
 291         state.private_data = private_data;
 292         return db->traverse(db, serverid_traverse_fn, &state);
 293 }