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