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