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