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 struct server_id server_id_db_pid(struct server_id_db *db)
  78 {
  79         return db->pid;
  80 }
  81
  82 static int server_id_db_destructor(struct server_id_db *db)
  83 {
  84         char *name = NULL;
  85
  86         while ((name = strv_next(db->names, name)) != NULL) {
  87                 server_id_db_remove(db, name);
  88         }
  89
  90         return 0;
  91 }
  92
  93 int server_id_db_add(struct server_id_db *db, const char *name)
  94 {
  95         struct tdb_context *tdb = db->tdb->tdb;
  96         struct server_id_buf buf;
  97         TDB_DATA key, data;
  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         server_id_str_buf(db->pid, &buf);
 114         data = string_term_tdb_data(buf.buf);
 115
 116         ret = tdb_append(tdb, key, data);
 117         if (ret != 0) {
 118                 enum TDB_ERROR err = tdb_error(tdb);
 119                 strv_delete(&db->names, strv_find(db->names, name));
 120                 return map_unix_error_from_tdb(err);
 121         }
 122
 123         return 0;
 124 }
 125
 126 int server_id_db_prune_name(struct server_id_db *db, const char *name,
 127                             struct server_id server)
 128 {
 129         struct tdb_context *tdb = db->tdb->tdb;
 130         struct server_id_buf buf;
 131         TDB_DATA key;
 132         uint8_t *data;
 133         char *ids, *id;
 134         int ret;
 135
 136         key = string_term_tdb_data(name);
 137         server_id_str_buf(server, &buf);
 138
 139         ret = tdb_chainlock(tdb, key);
 140         if (ret == -1) {
 141                 enum TDB_ERROR err = tdb_error(tdb);
 142                 return map_unix_error_from_tdb(err);
 143         }
 144
 145         ret = tdb_fetch_talloc(tdb, key, db, &data);
 146         if (ret != 0) {
 147                 tdb_chainunlock(tdb, key);
 148                 return ret;
 149         }
 150
 151         ids = (char *)data;
 152
 153         id = strv_find(ids, buf.buf);
 154         if (id == NULL) {
 155                 tdb_chainunlock(tdb, key);
 156                 TALLOC_FREE(data);
 157                 return ENOENT;
 158         }
 159
 160         strv_delete(&ids, id);
 161         ret = tdb_store(tdb, key, talloc_tdb_data(ids), TDB_MODIFY);
 162         TALLOC_FREE(data);
 163
 164         tdb_chainunlock(tdb, key);
 165
 166         return 0;
 167 }
 168
 169 int server_id_db_remove(struct server_id_db *db, const char *name)
 170 {
 171         char *n;
 172         int ret;
 173
 174         n = strv_find(db->names, name);
 175         if (n == NULL) {
 176                 return ENOENT;
 177         }
 178
 179         ret = server_id_db_prune_name(db, name, db->pid);
 180         if (ret != 0) {
 181                 return ret;
 182         }
 183
 184         strv_delete(&db->names, n);
 185         return 0;
 186 }
 187
 188 int server_id_db_lookup(struct server_id_db *db, const char *name,
 189                         TALLOC_CTX *mem_ctx, unsigned *pnum_servers,
 190                         struct server_id **pservers)
 191 {
 192         struct tdb_context *tdb = db->tdb->tdb;
 193         TDB_DATA key;
 194         uint8_t *data;
 195         char *ids, *id;
 196         unsigned num_servers;
 197         struct server_id *servers;
 198         int i, ret;
 199
 200         key = string_term_tdb_data(name);
 201
 202         ret = tdb_fetch_talloc(tdb, key, mem_ctx, &data);
 203         if (ret != 0) {
 204                 return ret;
 205         }
 206
 207         ids = (char *)data;
 208         num_servers = strv_count(ids);
 209
 210         servers = talloc_array(mem_ctx, struct server_id, num_servers);
 211         if (servers == NULL) {
 212                 TALLOC_FREE(data);
 213                 return ENOMEM;
 214         }
 215
 216         i = 0;
 217
 218         for (id = ids; id != NULL; id = strv_next(ids, id)) {
 219                 servers[i++] = server_id_from_string(NONCLUSTER_VNN, id);
 220         }
 221
 222         TALLOC_FREE(data);
 223
 224         *pnum_servers = num_servers;
 225         *pservers = servers;
 226
 227         return 0;
 228 }
 229
 230 bool server_id_db_lookup_one(struct server_id_db *db, const char *name,
 231                              struct server_id *server)
 232 {
 233         int ret;
 234         unsigned num_servers;
 235         struct server_id *servers;
 236
 237         ret = server_id_db_lookup(db, name, db, &num_servers, &servers);
 238         if (ret != 0) {
 239                 return false;
 240         }
 241         if (num_servers == 0) {
 242                 TALLOC_FREE(servers);
 243                 return false;
 244         }
 245         *server = servers[0];
 246         TALLOC_FREE(servers);
 247         return true;
 248 }
 249
 250 struct server_id_db_traverse_state {
 251         TALLOC_CTX *mem_ctx;
 252         int (*fn)(const char *name,
 253                   unsigned num_servers,
 254                   const struct server_id *servers,
 255                   void *private_data);
 256         void *private_data;
 257 };
 258
 259 static int server_id_db_traverse_fn(struct tdb_context *tdb,
 260                                     TDB_DATA key, TDB_DATA data,
 261                                     void *private_data)
 262 {
 263         struct server_id_db_traverse_state *state = private_data;
 264         const char *name;
 265         char *ids, *id;
 266         unsigned num_servers;
 267         struct server_id *servers;
 268         int i, ret;
 269
 270         if (key.dsize == 0) {
 271                 return 0;
 272         }
 273         if (key.dptr[key.dsize-1] != '\0') {
 274                 return 0;
 275         }
 276         name = (const char *)key.dptr;
 277
 278         ids = (char *)talloc_memdup(state->mem_ctx, data.dptr, data.dsize);
 279         if (ids == NULL) {
 280                 return 0;
 281         }
 282
 283         num_servers = strv_count(ids);
 284         servers = talloc_array(ids, struct server_id, num_servers);
 285
 286         i = 0;
 287
 288         for (id = ids; id != NULL; id = strv_next(ids, id)) {
 289                 servers[i++] = server_id_from_string(NONCLUSTER_VNN, id);
 290         }
 291
 292         ret = state->fn(name, num_servers, servers, state->private_data);
 293
 294         TALLOC_FREE(ids);
 295
 296         return ret;
 297 }
 298
 299 int server_id_db_traverse_read(struct server_id_db *db,
 300                                int (*fn)(const char *name,
 301                                          unsigned num_servers,
 302                                          const struct server_id *servers,
 303                                          void *private_data),
 304                                void *private_data)
 305 {
 306         struct server_id_db_traverse_state state;
 307         int ret;
 308
 309         state = (struct server_id_db_traverse_state) {
 310                 .fn = fn, .private_data = private_data,
 311                 .mem_ctx = talloc_new(db)
 312         };
 313
 314         if (state.mem_ctx == NULL) {
 315                 return ENOMEM;
 316         }
 317
 318         ret = tdb_traverse_read(db->tdb->tdb, server_id_db_traverse_fn,
 319                                 &state);
 320         TALLOC_FREE(state.mem_ctx);
 321         return ret;
 322 }