lib/util/server_id_db.c

   1 /*
   2  * Map names to server_ids
   3  *
   4  * Copyright Volker Lendecke <vl@samba.org> 2014
   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 "replace.h"
  21 #include "system/filesys.h"
  22 #include "lib/util/server_id.h"
  23 #include "lib/util/server_id_db.h"
  24 #include "lib/tdb_wrap/tdb_wrap.h"
  25 #include "lib/util/strv.h"
  26 #include "lib/util/util_tdb.h"
  27 #include "lib/util/samba_util.h"
  28
  29 static TDB_DATA talloc_tdb_data(void *ptr)
  30 {
  31         return (TDB_DATA) { .dptr = ptr, .dsize = talloc_get_size(ptr) };
  32 }
  33
  34 struct server_id_db {
  35         struct server_id pid;
  36         struct tdb_wrap *tdb;
  37         char *names;
  38 };
  39
  40 static int server_id_db_destructor(struct server_id_db *db);
  41
  42 struct server_id_db *server_id_db_init(TALLOC_CTX *mem_ctx,
  43                                        struct server_id pid,
  44                                        const char *base_path,
  45                                        int hash_size, int tdb_flags)
  46 {
  47         struct server_id_db *db;
  48         size_t pathlen = strlen(base_path) + 11;
  49         char path[pathlen];
  50
  51         db = talloc(mem_ctx, struct server_id_db);
  52         if (db == NULL) {
  53                 return NULL;
  54         }
  55         db->pid = pid;
  56         db->names = NULL;
  57
  58         snprintf(path, pathlen, "%s/names.tdb", base_path);
  59
  60         db->tdb = tdb_wrap_open(db, path, hash_size, tdb_flags,
  61                                 O_RDWR|O_CREAT, 0660);
  62         if (db->tdb == NULL) {
  63                 TALLOC_FREE(db);
  64                 return NULL;
  65         }
  66
  67         talloc_set_destructor(db, server_id_db_destructor);
  68
  69         return db;
  70 }
  71
  72 void server_id_db_reinit(struct server_id_db *db, struct server_id pid)
  73 {
  74         db->pid = pid;
  75         TALLOC_FREE(db->names);
  76 }
  77
  78 struct server_id server_id_db_pid(struct server_id_db *db)
  79 {
  80         return db->pid;
  81 }
  82
  83 static int server_id_db_destructor(struct server_id_db *db)
  84 {
  85         char *name = NULL;
  86
  87         while ((name = strv_next(db->names, name)) != NULL) {
  88                 server_id_db_remove(db, name);
  89         }
  90
  91         return 0;
  92 }
  93
  94 int server_id_db_add(struct server_id_db *db, const char *name)
  95 {
  96         struct tdb_context *tdb = db->tdb->tdb;
  97         TDB_DATA key;
  98         char *n;
  99         int ret;
 100
 101         n = strv_find(db->names, name);
 102         if (n != NULL) {
 103                 return EEXIST;
 104         }
 105
 106         ret = strv_add(db, &db->names, name);
 107         if (ret != 0) {
 108                 return ret;
 109         }
 110
 111         key = string_term_tdb_data(name);
 112
 113         {
 114                 struct server_id_buf _buf;
 115                 char *idbuf = server_id_str_buf_unique(db->pid, &_buf);
 116                 size_t idlen = strlen(idbuf) + 1;
 117
 118                 ret = tdb_append(
 119                         tdb, key,
 120                         (TDB_DATA) { .dptr = (uint8_t *)idbuf, .dsize = idlen });
 121         }
 122
 123         if (ret != 0) {
 124                 enum TDB_ERROR err = tdb_error(tdb);
 125                 strv_delete(&db->names, strv_find(db->names, name));
 126                 return map_unix_error_from_tdb(err);
 127         }
 128
 129         return 0;
 130 }
 131
 132 int server_id_db_prune_name(struct server_id_db *db, const char *name,
 133                             struct server_id server)
 134 {
 135         struct tdb_context *tdb = db->tdb->tdb;
 136         struct server_id_buf _buf;
 137         char *idbuf = server_id_str_buf_unique(server, &_buf);
 138         TDB_DATA key;
 139         uint8_t *data;
 140         size_t datalen;
 141         char *ids, *id;
 142         int ret;
 143
 144         key = string_term_tdb_data(name);
 145
 146         ret = tdb_chainlock(tdb, key);
 147         if (ret == -1) {
 148                 enum TDB_ERROR err = tdb_error(tdb);
 149                 return map_unix_error_from_tdb(err);
 150         }
 151
 152         ret = tdb_fetch_talloc(tdb, key, db, &data);
 153         if (ret != 0) {
 154                 tdb_chainunlock(tdb, key);
 155                 return ret;
 156         }
 157
 158         datalen = talloc_get_size(data);
 159         if ((datalen == 0) || (data[datalen-1] != '\0')) {
 160                 tdb_chainunlock(tdb, key);
 161                 TALLOC_FREE(data);
 162                 return EINVAL;
 163         }
 164
 165         ids = (char *)data;
 166
 167         id = strv_find(ids, idbuf);
 168         if (id == NULL) {
 169                 tdb_chainunlock(tdb, key);
 170                 TALLOC_FREE(data);
 171                 return ENOENT;
 172         }
 173
 174         strv_delete(&ids, id);
 175
 176         if (talloc_get_size(ids) == 0) {
 177                 ret = tdb_delete(tdb, key);
 178         } else {
 179                 ret = tdb_store(tdb, key, talloc_tdb_data(ids), TDB_MODIFY);
 180         }
 181         TALLOC_FREE(data);
 182
 183         tdb_chainunlock(tdb, key);
 184
 185         if (ret == -1) {
 186                 enum TDB_ERROR err = tdb_error(tdb);
 187                 return map_unix_error_from_tdb(err);
 188         }
 189
 190         return 0;
 191 }
 192
 193 int server_id_db_remove(struct server_id_db *db, const char *name)
 194 {
 195         char *n;
 196         int ret;
 197
 198         n = strv_find(db->names, name);
 199         if (n == NULL) {
 200                 return ENOENT;
 201         }
 202
 203         ret = server_id_db_prune_name(db, name, db->pid);
 204         if (ret != 0) {
 205                 return ret;
 206         }
 207
 208         strv_delete(&db->names, n);
 209         return 0;
 210 }
 211
 212 int server_id_db_lookup(struct server_id_db *db, const char *name,
 213                         TALLOC_CTX *mem_ctx, unsigned *pnum_servers,
 214                         struct server_id **pservers)
 215 {
 216         struct tdb_context *tdb = db->tdb->tdb;
 217         TDB_DATA key;
 218         uint8_t *data;
 219         size_t datalen;
 220         char *ids, *id;
 221         unsigned num_servers;
 222         struct server_id *servers;
 223         int i, ret;
 224
 225         key = string_term_tdb_data(name);
 226
 227         ret = tdb_fetch_talloc(tdb, key, mem_ctx, &data);
 228         if (ret != 0) {
 229                 return ret;
 230         }
 231
 232         datalen = talloc_get_size(data);
 233         if ((datalen == 0) || (data[datalen-1] != '\0')) {
 234                 TALLOC_FREE(data);
 235                 return EINVAL;
 236         }
 237
 238         ids = (char *)data;
 239         num_servers = strv_count(ids);
 240
 241         servers = talloc_array(mem_ctx, struct server_id, num_servers);
 242         if (servers == NULL) {
 243                 TALLOC_FREE(data);
 244                 return ENOMEM;
 245         }
 246
 247         i = 0;
 248
 249         for (id = ids; id != NULL; id = strv_next(ids, id)) {
 250                 servers[i++] = server_id_from_string(NONCLUSTER_VNN, id);
 251         }
 252
 253         TALLOC_FREE(data);
 254
 255         *pnum_servers = num_servers;
 256         *pservers = servers;
 257
 258         return 0;
 259 }
 260
 261 bool server_id_db_lookup_one(struct server_id_db *db, const char *name,
 262                              struct server_id *server)
 263 {
 264         int ret;
 265         unsigned num_servers;
 266         struct server_id *servers;
 267
 268         ret = server_id_db_lookup(db, name, db, &num_servers, &servers);
 269         if (ret != 0) {
 270                 return false;
 271         }
 272         if (num_servers == 0) {
 273                 TALLOC_FREE(servers);
 274                 return false;
 275         }
 276         *server = servers[0];
 277         TALLOC_FREE(servers);
 278         return true;
 279 }
 280
 281 struct server_id_db_traverse_state {
 282         TALLOC_CTX *mem_ctx;
 283         int (*fn)(const char *name,
 284                   unsigned num_servers,
 285                   const struct server_id *servers,
 286                   void *private_data);
 287         void *private_data;
 288 };
 289
 290 static int server_id_db_traverse_fn(struct tdb_context *tdb,
 291                                     TDB_DATA key, TDB_DATA data,
 292                                     void *private_data)
 293 {
 294         struct server_id_db_traverse_state *state = private_data;
 295         const char *name;
 296         char *ids, *id;
 297         unsigned num_servers;
 298         struct server_id *servers;
 299         int i, ret;
 300
 301         if (key.dsize == 0) {
 302                 return 0;
 303         }
 304         if (key.dptr[key.dsize-1] != '\0') {
 305                 return 0;
 306         }
 307         name = (const char *)key.dptr;
 308
 309         ids = (char *)talloc_memdup(state->mem_ctx, data.dptr, data.dsize);
 310         if (ids == NULL) {
 311                 return 0;
 312         }
 313
 314         num_servers = strv_count(ids);
 315         servers = talloc_array(ids, struct server_id, num_servers);
 316
 317         i = 0;
 318
 319         for (id = ids; id != NULL; id = strv_next(ids, id)) {
 320                 servers[i++] = server_id_from_string(NONCLUSTER_VNN, id);
 321         }
 322
 323         ret = state->fn(name, num_servers, servers, state->private_data);
 324
 325         TALLOC_FREE(ids);
 326
 327         return ret;
 328 }
 329
 330 int server_id_db_traverse_read(struct server_id_db *db,
 331                                int (*fn)(const char *name,
 332                                          unsigned num_servers,
 333                                          const struct server_id *servers,
 334                                          void *private_data),
 335                                void *private_data)
 336 {
 337         struct server_id_db_traverse_state state;
 338         int ret;
 339
 340         state = (struct server_id_db_traverse_state) {
 341                 .fn = fn, .private_data = private_data,
 342                 .mem_ctx = talloc_new(db)
 343         };
 344
 345         if (state.mem_ctx == NULL) {
 346                 return ENOMEM;
 347         }
 348
 349         ret = tdb_traverse_read(db->tdb->tdb, server_id_db_traverse_fn,
 350                                 &state);
 351         TALLOC_FREE(state.mem_ctx);
 352         return ret;
 353 }