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