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                 size_t idlen = server_id_str_buf_unique(db->pid, NULL, 0);
 115                 char idbuf[idlen];
 116
 117                 server_id_str_buf_unique(db->pid, idbuf, idlen);
 118
 119                 ret = tdb_append(
 120                         tdb, key,
 121                         (TDB_DATA) { .dptr = (uint8_t *)idbuf, .dsize = idlen });
 122         }
 123
 124         if (ret != 0) {
 125                 enum TDB_ERROR err = tdb_error(tdb);
 126                 strv_delete(&db->names, strv_find(db->names, name));
 127                 return map_unix_error_from_tdb(err);
 128         }
 129
 130         return 0;
 131 }
 132
 133 int server_id_db_prune_name(struct server_id_db *db, const char *name,
 134                             struct server_id server)
 135 {
 136         struct tdb_context *tdb = db->tdb->tdb;
 137         size_t idbuf_len = server_id_str_buf_unique(server, NULL, 0);
 138         char idbuf[idbuf_len];
 139         TDB_DATA key;
 140         uint8_t *data;
 141         size_t datalen;
 142         char *ids, *id;
 143         int ret;
 144
 145         key = string_term_tdb_data(name);
 146         server_id_str_buf_unique(server, idbuf, idbuf_len);
 147
 148         ret = tdb_chainlock(tdb, key);
 149         if (ret == -1) {
 150                 enum TDB_ERROR err = tdb_error(tdb);
 151                 return map_unix_error_from_tdb(err);
 152         }
 153
 154         ret = tdb_fetch_talloc(tdb, key, db, &data);
 155         if (ret != 0) {
 156                 tdb_chainunlock(tdb, key);
 157                 return ret;
 158         }
 159
 160         datalen = talloc_get_size(data);
 161         if ((datalen == 0) || (data[datalen-1] != '\0')) {
 162                 tdb_chainunlock(tdb, key);
 163                 TALLOC_FREE(data);
 164                 return EINVAL;
 165         }
 166
 167         ids = (char *)data;
 168
 169         id = strv_find(ids, idbuf);
 170         if (id == NULL) {
 171                 tdb_chainunlock(tdb, key);
 172                 TALLOC_FREE(data);
 173                 return ENOENT;
 174         }
 175
 176         strv_delete(&ids, id);
 177
 178         if (talloc_get_size(ids) == 0) {
 179                 ret = tdb_delete(tdb, key);
 180         } else {
 181                 ret = tdb_store(tdb, key, talloc_tdb_data(ids), TDB_MODIFY);
 182         }
 183         TALLOC_FREE(data);
 184
 185         tdb_chainunlock(tdb, key);
 186
 187         return 0;
 188 }
 189
 190 int server_id_db_remove(struct server_id_db *db, const char *name)
 191 {
 192         char *n;
 193         int ret;
 194
 195         n = strv_find(db->names, name);
 196         if (n == NULL) {
 197                 return ENOENT;
 198         }
 199
 200         ret = server_id_db_prune_name(db, name, db->pid);
 201         if (ret != 0) {
 202                 return ret;
 203         }
 204
 205         strv_delete(&db->names, n);
 206         return 0;
 207 }
 208
 209 int server_id_db_lookup(struct server_id_db *db, const char *name,
 210                         TALLOC_CTX *mem_ctx, unsigned *pnum_servers,
 211                         struct server_id **pservers)
 212 {
 213         struct tdb_context *tdb = db->tdb->tdb;
 214         TDB_DATA key;
 215         uint8_t *data;
 216         size_t datalen;
 217         char *ids, *id;
 218         unsigned num_servers;
 219         struct server_id *servers;
 220         int i, ret;
 221
 222         key = string_term_tdb_data(name);
 223
 224         ret = tdb_fetch_talloc(tdb, key, mem_ctx, &data);
 225         if (ret != 0) {
 226                 return ret;
 227         }
 228
 229         datalen = talloc_get_size(data);
 230         if ((datalen == 0) || (data[datalen-1] != '\0')) {
 231                 TALLOC_FREE(data);
 232                 return EINVAL;
 233         }
 234
 235         ids = (char *)data;
 236         num_servers = strv_count(ids);
 237
 238         servers = talloc_array(mem_ctx, struct server_id, num_servers);
 239         if (servers == NULL) {
 240                 TALLOC_FREE(data);
 241                 return ENOMEM;
 242         }
 243
 244         i = 0;
 245
 246         for (id = ids; id != NULL; id = strv_next(ids, id)) {
 247                 servers[i++] = server_id_from_string(NONCLUSTER_VNN, id);
 248         }
 249
 250         TALLOC_FREE(data);
 251
 252         *pnum_servers = num_servers;
 253         *pservers = servers;
 254
 255         return 0;
 256 }
 257
 258 bool server_id_db_lookup_one(struct server_id_db *db, const char *name,
 259                              struct server_id *server)
 260 {
 261         int ret;
 262         unsigned num_servers;
 263         struct server_id *servers;
 264
 265         ret = server_id_db_lookup(db, name, db, &num_servers, &servers);
 266         if (ret != 0) {
 267                 return false;
 268         }
 269         if (num_servers == 0) {
 270                 TALLOC_FREE(servers);
 271                 return false;
 272         }
 273         *server = servers[0];
 274         TALLOC_FREE(servers);
 275         return true;
 276 }
 277
 278 struct server_id_db_traverse_state {
 279         TALLOC_CTX *mem_ctx;
 280         int (*fn)(const char *name,
 281                   unsigned num_servers,
 282                   const struct server_id *servers,
 283                   void *private_data);
 284         void *private_data;
 285 };
 286
 287 static int server_id_db_traverse_fn(struct tdb_context *tdb,
 288                                     TDB_DATA key, TDB_DATA data,
 289                                     void *private_data)
 290 {
 291         struct server_id_db_traverse_state *state = private_data;
 292         const char *name;
 293         char *ids, *id;
 294         unsigned num_servers;
 295         struct server_id *servers;
 296         int i, ret;
 297
 298         if (key.dsize == 0) {
 299                 return 0;
 300         }
 301         if (key.dptr[key.dsize-1] != '\0') {
 302                 return 0;
 303         }
 304         name = (const char *)key.dptr;
 305
 306         ids = (char *)talloc_memdup(state->mem_ctx, data.dptr, data.dsize);
 307         if (ids == NULL) {
 308                 return 0;
 309         }
 310
 311         num_servers = strv_count(ids);
 312         servers = talloc_array(ids, struct server_id, num_servers);
 313
 314         i = 0;
 315
 316         for (id = ids; id != NULL; id = strv_next(ids, id)) {
 317                 servers[i++] = server_id_from_string(NONCLUSTER_VNN, id);
 318         }
 319
 320         ret = state->fn(name, num_servers, servers, state->private_data);
 321
 322         TALLOC_FREE(ids);
 323
 324         return ret;
 325 }
 326
 327 int server_id_db_traverse_read(struct server_id_db *db,
 328                                int (*fn)(const char *name,
 329                                          unsigned num_servers,
 330                                          const struct server_id *servers,
 331                                          void *private_data),
 332                                void *private_data)
 333 {
 334         struct server_id_db_traverse_state state;
 335         int ret;
 336
 337         state = (struct server_id_db_traverse_state) {
 338                 .fn = fn, .private_data = private_data,
 339                 .mem_ctx = talloc_new(db)
 340         };
 341
 342         if (state.mem_ctx == NULL) {
 343                 return ENOMEM;
 344         }
 345
 346         ret = tdb_traverse_read(db->tdb->tdb, server_id_db_traverse_fn,
 347                                 &state);
 348         TALLOC_FREE(state.mem_ctx);
 349         return ret;
 350 }