lib/ldb-samba/ldb_wrap.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    LDB wrap functions
   5
   6    Copyright (C) Andrew Tridgell 2004-2009
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 /*
  23   the stupidity of the unix fcntl locking design forces us to never
  24   allow a database file to be opened twice in the same process. These
  25   wrappers provide convenient access to a tdb or ldb, taking advantage
  26   of talloc destructors to ensure that only a single open is done
  27 */
  28
  29 #include "includes.h"
  30 #include "lib/events/events.h"
  31 #include <ldb.h>
  32 #include <ldb_errors.h>
  33 #include "lib/ldb-samba/ldif_handlers.h"
  34 #include "ldb_wrap.h"
  35 #include "dsdb/samdb/samdb.h"
  36 #include "param/param.h"
  37 #include "../lib/util/dlinklist.h"
  38 #include "../lib/tdb_compat/tdb_compat.h"
  39
  40 /*
  41   this is used to catch debug messages from ldb
  42 */
  43 static void ldb_wrap_debug(void *context, enum ldb_debug_level level,
  44                            const char *fmt, va_list ap)  PRINTF_ATTRIBUTE(3,0);
  45
  46 static void ldb_wrap_debug(void *context, enum ldb_debug_level level,
  47                            const char *fmt, va_list ap)
  48 {
  49         int samba_level = -1;
  50         char *s = NULL;
  51         switch (level) {
  52         case LDB_DEBUG_FATAL:
  53                 samba_level = 0;
  54                 break;
  55         case LDB_DEBUG_ERROR:
  56                 samba_level = 1;
  57                 break;
  58         case LDB_DEBUG_WARNING:
  59                 samba_level = 2;
  60                 break;
  61         case LDB_DEBUG_TRACE:
  62                 samba_level = 5;
  63                 break;
  64
  65         };
  66         vasprintf(&s, fmt, ap);
  67         if (!s) return;
  68         DEBUG(samba_level, ("ldb: %s\n", s));
  69         free(s);
  70 }
  71
  72
  73 /*
  74   connecting to a ldb can be a relatively expensive operation because
  75   of the schema and partition loads. We keep a list of open ldb
  76   contexts here, and try to re-use when possible.
  77
  78   This means callers of ldb_wrap_connect() must use talloc_unlink() or
  79   the free of a parent to destroy the context
  80  */
  81 static struct ldb_wrap {
  82         struct ldb_wrap *next, *prev;
  83         struct ldb_wrap_context {
  84                 /* the context is what we use to tell if two ldb
  85                  * connections are exactly equivalent
  86                  */
  87                 const char *url;
  88                 struct tevent_context *ev;
  89                 struct loadparm_context *lp_ctx;
  90                 struct auth_session_info *session_info;
  91                 struct cli_credentials *credentials;
  92                 unsigned int flags;
  93         } context;
  94         struct ldb_context *ldb;
  95 } *ldb_wrap_list;
  96
  97 /*
  98    free a ldb_wrap structure
  99  */
 100 static int ldb_wrap_destructor(struct ldb_wrap *w)
 101 {
 102         DLIST_REMOVE(ldb_wrap_list, w);
 103         return 0;
 104 }
 105
 106 /*
 107  * The casefolder for s4's LDB databases - Unicode-safe
 108  */
 109 char *wrap_casefold(void *context, void *mem_ctx, const char *s, size_t n)
 110 {
 111         return strupper_talloc_n(mem_ctx, s, n);
 112 }
 113
 114
 115  struct ldb_context *samba_ldb_init(TALLOC_CTX *mem_ctx,
 116                                     struct tevent_context *ev,
 117                                     struct loadparm_context *lp_ctx,
 118                                     struct auth_session_info *session_info,
 119                                     struct cli_credentials *credentials)
 120 {
 121         struct ldb_context *ldb;
 122         int ret;
 123
 124         ldb = ldb_init(mem_ctx, ev);
 125         if (ldb == NULL) {
 126                 return NULL;
 127         }
 128
 129         ldb_set_modules_dir(ldb, modules_path(ldb, "ldb"));
 130
 131         ldb_set_debug(ldb, ldb_wrap_debug, NULL);
 132
 133         ldb_set_utf8_fns(ldb, NULL, wrap_casefold);
 134
 135         if (session_info) {
 136                 if (ldb_set_opaque(ldb, "sessionInfo", session_info)) {
 137                         talloc_free(ldb);
 138                         return NULL;
 139                 }
 140         }
 141
 142         if (credentials) {
 143                 if (ldb_set_opaque(ldb, "credentials", credentials)) {
 144                         talloc_free(ldb);
 145                         return NULL;
 146                 }
 147         }
 148
 149         if (ldb_set_opaque(ldb, "loadparm", lp_ctx)) {
 150                 talloc_free(ldb);
 151                 return NULL;
 152         }
 153
 154         /* This must be done before we load the schema, as these
 155          * handlers for objectSid and objectGUID etc must take
 156          * precedence over the 'binary attribute' declaration in the
 157          * schema */
 158         ret = ldb_register_samba_handlers(ldb);
 159         if (ret != LDB_SUCCESS) {
 160                 talloc_free(ldb);
 161                 return NULL;
 162         }
 163
 164         /* we usually want Samba databases to be private. If we later
 165            find we need one public, we will need to add a parameter to
 166            ldb_wrap_connect() */
 167         ldb_set_create_perms(ldb, 0600);
 168
 169         return ldb;
 170 }
 171
 172  struct ldb_context *ldb_wrap_find(const char *url,
 173                                    struct tevent_context *ev,
 174                                    struct loadparm_context *lp_ctx,
 175                                    struct auth_session_info *session_info,
 176                                    struct cli_credentials *credentials,
 177                                    unsigned int flags)
 178 {
 179         struct ldb_wrap *w;
 180         /* see if we can re-use an existing ldb */
 181         for (w=ldb_wrap_list; w; w=w->next) {
 182                 if (w->context.ev == ev &&
 183                     w->context.lp_ctx == lp_ctx &&
 184                     w->context.session_info == session_info &&
 185                     w->context.credentials == credentials &&
 186                     w->context.flags == flags &&
 187                     (w->context.url == url || strcmp(w->context.url, url) == 0))
 188                         return w->ldb;
 189         }
 190
 191         return NULL;
 192 }
 193
 194 int samba_ldb_connect(struct ldb_context *ldb, struct loadparm_context *lp_ctx,
 195                       const char *url, unsigned int flags)
 196 {
 197         int ret;
 198         char *real_url = NULL;
 199
 200         /* allow admins to force non-sync ldb for all databases */
 201         if (lpcfg_parm_bool(lp_ctx, NULL, "ldb", "nosync", false)) {
 202                 flags |= LDB_FLG_NOSYNC;
 203         }
 204
 205         if (DEBUGLVL(10)) {
 206                 flags |= LDB_FLG_ENABLE_TRACING;
 207         }
 208
 209         real_url = lpcfg_private_path(ldb, lp_ctx, url);
 210         if (real_url == NULL) {
 211                 return LDB_ERR_OPERATIONS_ERROR;
 212         }
 213
 214         ret = ldb_connect(ldb, real_url, flags, NULL);
 215
 216         if (ret != LDB_SUCCESS) {
 217                 return ret;
 218         }
 219
 220         /* setup for leak detection */
 221         ldb_set_opaque(ldb, "wrap_url", real_url);
 222
 223         return LDB_SUCCESS;
 224 }
 225
 226  bool ldb_wrap_add(const char *url, struct tevent_context *ev,
 227                    struct loadparm_context *lp_ctx,
 228                    struct auth_session_info *session_info,
 229                    struct cli_credentials *credentials,
 230                    unsigned int flags,
 231                    struct ldb_context *ldb)
 232 {
 233         struct ldb_wrap *w;
 234         struct ldb_wrap_context c;
 235
 236         /* add to the list of open ldb contexts */
 237         w = talloc(ldb, struct ldb_wrap);
 238         if (w == NULL) {
 239                 return false;
 240         }
 241
 242         c.url          = url;
 243         c.ev           = ev;
 244         c.lp_ctx       = lp_ctx;
 245         c.session_info = session_info;
 246         c.credentials  = credentials;
 247         c.flags        = flags;
 248
 249         w->context = c;
 250         w->context.url = talloc_strdup(w, url);
 251         if (w->context.url == NULL) {
 252                 return false;
 253         }
 254
 255         if (session_info) {
 256                 /* take a reference to the session_info, as it is
 257                  * possible for the ldb to live longer than the
 258                  * session_info. This happens when a DRS DsBind call
 259                  * reuses a handle, but the original connection is
 260                  * shutdown. The token for the new connection is still
 261                  * valid, so we need the session_info to remain valid for
 262                  * ldb modules to use
 263                  */
 264                 if (talloc_reference(w, session_info) == NULL) {
 265                         return false;
 266                 }
 267         }
 268
 269         w->ldb = ldb;
 270
 271         DLIST_ADD(ldb_wrap_list, w);
 272
 273         talloc_set_destructor(w, ldb_wrap_destructor);
 274
 275         return true;
 276 }
 277
 278
 279 /*
 280   wrapped connection to a ldb database
 281   to close just talloc_free() the returned ldb_context
 282
 283   TODO:  We need an error_string parameter
 284  */
 285  struct ldb_context *ldb_wrap_connect(TALLOC_CTX *mem_ctx,
 286                                       struct tevent_context *ev,
 287                                       struct loadparm_context *lp_ctx,
 288                                       const char *url,
 289                                       struct auth_session_info *session_info,
 290                                       struct cli_credentials *credentials,
 291                                       unsigned int flags)
 292 {
 293         struct ldb_context *ldb;
 294         int ret;
 295
 296         ldb = ldb_wrap_find(url, ev, lp_ctx, session_info, credentials, flags);
 297         if (ldb != NULL)
 298                 return talloc_reference(mem_ctx, ldb);
 299
 300         ldb = samba_ldb_init(mem_ctx, ev, lp_ctx, session_info, credentials);
 301
 302         if (ldb == NULL)
 303                 return NULL;
 304
 305         ret = samba_ldb_connect(ldb, lp_ctx, url, flags);
 306         if (ret != LDB_SUCCESS) {
 307                 talloc_free(ldb);
 308                 return NULL;
 309         }
 310
 311         if (!ldb_wrap_add(url, ev, lp_ctx, session_info, credentials, flags, ldb)) {
 312                 talloc_free(ldb);
 313                 return NULL;
 314         }
 315
 316         DEBUG(3,("ldb_wrap open of %s\n", url));
 317
 318         return ldb;
 319 }
 320
 321 /*
 322   when we fork() we need to make sure that any open ldb contexts have
 323   any open transactions cancelled
 324  */
 325  void ldb_wrap_fork_hook(void)
 326 {
 327         struct ldb_wrap *w;
 328
 329         for (w=ldb_wrap_list; w; w=w->next) {
 330                 if (ldb_transaction_cancel_noerr(w->ldb) != LDB_SUCCESS) {
 331                         smb_panic("Failed to cancel child transactions\n");
 332                 }
 333         }
 334
 335         if (tdb_reopen_all(1) != 0) {
 336                 smb_panic("tdb_reopen_all failed\n");
 337         }
 338 }
 339
 340  char *ldb_relative_path(struct ldb_context *ldb,
 341                          TALLOC_CTX *mem_ctx,
 342                          const char *name)
 343 {
 344         const char *base_url =
 345                 (const char *)ldb_get_opaque(ldb, "ldb_url");
 346         char *path, *p, *full_name;
 347         if (name == NULL) {
 348                 return NULL;
 349         }
 350         if (strncmp("tdb://", base_url, 6) == 0) {
 351                 base_url = base_url+6;
 352         }
 353         path = talloc_strdup(mem_ctx, base_url);
 354         if (path == NULL) {
 355                 return NULL;
 356         }
 357         if ( (p = strrchr(path, '/')) != NULL) {
 358                 p[0] = '\0';
 359                 full_name = talloc_asprintf(mem_ctx, "%s/%s", path, name);
 360         } else {
 361                 full_name = talloc_asprintf(mem_ctx, "./%s", name);
 362         }
 363         talloc_free(path);
 364         return full_name;
 365 }