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 "dsdb/common/util.h"
  37 #include "param/param.h"
  38 #include "../lib/util/dlinklist.h"
  39 #include "lib/util/util_paths.h"
  40 #include <tdb.h>
  41 #include <unistd.h>
  42
  43 #undef DBGC_CLASS
  44 #define DBGC_CLASS DBGC_LDB
  45
  46 /*
  47   this is used to catch debug messages from ldb
  48 */
  49 static void ldb_wrap_debug(void *context, enum ldb_debug_level level,
  50                            const char *fmt, va_list ap)  PRINTF_ATTRIBUTE(3,0);
  51
  52 static void ldb_wrap_debug(void *context, enum ldb_debug_level level,
  53                            const char *fmt, va_list ap)
  54 {
  55         int samba_level = -1;
  56         switch (level) {
  57         case LDB_DEBUG_FATAL:
  58                 samba_level = DBGLVL_ERR;
  59                 break;
  60         case LDB_DEBUG_ERROR:
  61                 samba_level = DBGLVL_WARNING;
  62                 break;
  63         case LDB_DEBUG_WARNING:
  64                 samba_level = DBGLVL_NOTICE;
  65                 break;
  66         case LDB_DEBUG_TRACE:
  67                 samba_level = DBGLVL_DEBUG + 1;
  68                 break;
  69
  70         };
  71         if (CHECK_DEBUGLVL(samba_level)) {
  72                 char *s = NULL;
  73                 int ret;
  74
  75                 ret = vasprintf(&s, fmt, ap);
  76                 if (ret == -1) {
  77                         return;
  78                 }
  79                 DEBUG(samba_level, ("ldb: %s\n", s));
  80                 free(s);
  81         }
  82 }
  83
  84
  85 /*
  86   connecting to a ldb can be a relatively expensive operation because
  87   of the schema and partition loads. We keep a list of open ldb
  88   contexts here, and try to re-use when possible.
  89
  90   This means callers of ldb_wrap_connect() must use talloc_unlink() or
  91   the free of a parent to destroy the context
  92  */
  93 static struct ldb_wrap {
  94         struct ldb_wrap *next, *prev;
  95         struct ldb_wrap_context {
  96                 /* the context is what we use to tell if two ldb
  97                  * connections are exactly equivalent
  98                  */
  99                 pid_t pid; /* We want to re-open in a new PID due to
 100                             * the LMDB backend */
 101                 const char *url;
 102                 struct tevent_context *ev;
 103                 struct loadparm_context *lp_ctx;
 104                 struct auth_session_info *session_info;
 105                 struct cli_credentials *credentials;
 106                 unsigned int flags;
 107         } context;
 108         struct ldb_context *ldb;
 109 } *ldb_wrap_list;
 110
 111 /*
 112    free a ldb_wrap structure
 113  */
 114 static int ldb_wrap_destructor(struct ldb_wrap *w)
 115 {
 116         DLIST_REMOVE(ldb_wrap_list, w);
 117         return 0;
 118 }
 119
 120 /*
 121  * The casefolder for s4's LDB databases - Unicode-safe
 122  */
 123 char *wrap_casefold(void *context, void *mem_ctx, const char *s, size_t n)
 124 {
 125         return strupper_talloc_n(mem_ctx, s, n);
 126 }
 127
 128
 129  struct ldb_context *samba_ldb_init(TALLOC_CTX *mem_ctx,
 130                                     struct tevent_context *ev,
 131                                     struct loadparm_context *lp_ctx,
 132                                     struct auth_session_info *session_info,
 133                                     struct cli_credentials *credentials)
 134 {
 135         struct ldb_context *ldb;
 136         int ret;
 137
 138         ldb = ldb_init(mem_ctx, ev);
 139         if (ldb == NULL) {
 140                 return NULL;
 141         }
 142
 143         ldb_set_modules_dir(ldb, modules_path(ldb, "ldb"));
 144
 145         ldb_set_debug(ldb, ldb_wrap_debug, NULL);
 146
 147         ldb_set_utf8_fns(ldb, NULL, wrap_casefold);
 148
 149         if (session_info) {
 150                 if (ldb_set_opaque(ldb, DSDB_SESSION_INFO, session_info)) {
 151                         talloc_free(ldb);
 152                         return NULL;
 153                 }
 154         }
 155
 156         if (credentials) {
 157                 if (ldb_set_opaque(ldb, "credentials", credentials)) {
 158                         talloc_free(ldb);
 159                         return NULL;
 160                 }
 161         }
 162
 163         if (ldb_set_opaque(ldb, "loadparm", lp_ctx)) {
 164                 talloc_free(ldb);
 165                 return NULL;
 166         }
 167
 168         /* This must be done before we load the schema, as these
 169          * handlers for objectSid and objectGUID etc must take
 170          * precedence over the 'binary attribute' declaration in the
 171          * schema */
 172         ret = ldb_register_samba_handlers(ldb);
 173         if (ret != LDB_SUCCESS) {
 174                 talloc_free(ldb);
 175                 return NULL;
 176         }
 177
 178         /* we usually want Samba databases to be private. If we later
 179            find we need one public, we will need to add a parameter to
 180            ldb_wrap_connect() */
 181         ldb_set_create_perms(ldb, 0600);
 182
 183         return ldb;
 184 }
 185
 186  struct ldb_context *ldb_wrap_find(const char *url,
 187                                    struct tevent_context *ev,
 188                                    struct loadparm_context *lp_ctx,
 189                                    struct auth_session_info *session_info,
 190                                    struct cli_credentials *credentials,
 191                                    unsigned int flags)
 192 {
 193         pid_t pid = getpid();
 194         struct ldb_wrap *w;
 195         /* see if we can re-use an existing ldb */
 196         for (w=ldb_wrap_list; w; w=w->next) {
 197                 if (w->context.pid == pid &&
 198                     w->context.ev == ev &&
 199                     w->context.lp_ctx == lp_ctx &&
 200                     w->context.session_info == session_info &&
 201                     w->context.credentials == credentials &&
 202                     w->context.flags == flags &&
 203                     (w->context.url == url || strcmp(w->context.url, url) == 0))
 204                         return w->ldb;
 205         }
 206
 207         return NULL;
 208 }
 209
 210 int samba_ldb_connect(struct ldb_context *ldb, struct loadparm_context *lp_ctx,
 211                       const char *url, unsigned int flags)
 212 {
 213         int ret;
 214         char *real_url = NULL;
 215
 216         /* allow admins to force non-sync ldb for all databases */
 217         if (lpcfg_parm_bool(lp_ctx, NULL, "ldb", "nosync", false)) {
 218                 flags |= LDB_FLG_NOSYNC;
 219         }
 220
 221         if (DEBUGLVL(10)) {
 222                 flags |= LDB_FLG_ENABLE_TRACING;
 223         }
 224
 225         real_url = lpcfg_private_path(ldb, lp_ctx, url);
 226         if (real_url == NULL) {
 227                 return LDB_ERR_OPERATIONS_ERROR;
 228         }
 229
 230         ret = ldb_connect(ldb, real_url, flags, NULL);
 231
 232         if (ret != LDB_SUCCESS) {
 233                 return ret;
 234         }
 235
 236         /* setup for leak detection */
 237         ldb_set_opaque(ldb, "wrap_url", real_url);
 238
 239         return LDB_SUCCESS;
 240 }
 241
 242  bool ldb_wrap_add(const char *url, struct tevent_context *ev,
 243                    struct loadparm_context *lp_ctx,
 244                    struct auth_session_info *session_info,
 245                    struct cli_credentials *credentials,
 246                    unsigned int flags,
 247                    struct ldb_context *ldb)
 248 {
 249         struct ldb_wrap *w;
 250         struct ldb_wrap_context c;
 251
 252         /* add to the list of open ldb contexts */
 253         w = talloc(ldb, struct ldb_wrap);
 254         if (w == NULL) {
 255                 return false;
 256         }
 257
 258         c.pid          = getpid();
 259         c.url          = url;
 260         c.ev           = ev;
 261         c.lp_ctx       = lp_ctx;
 262         c.session_info = session_info;
 263         c.credentials  = credentials;
 264         c.flags        = flags;
 265
 266         w->context = c;
 267         w->context.url = talloc_strdup(w, url);
 268         if (w->context.url == NULL) {
 269                 return false;
 270         }
 271
 272         if (session_info) {
 273                 /* take a reference to the session_info, as it is
 274                  * possible for the ldb to live longer than the
 275                  * session_info. This happens when a DRS DsBind call
 276                  * reuses a handle, but the original connection is
 277                  * shutdown. The token for the new connection is still
 278                  * valid, so we need the session_info to remain valid for
 279                  * ldb modules to use
 280                  */
 281                 if (talloc_reference(w, session_info) == NULL) {
 282                         return false;
 283                 }
 284         }
 285
 286         w->ldb = ldb;
 287
 288         DLIST_ADD(ldb_wrap_list, w);
 289
 290         talloc_set_destructor(w, ldb_wrap_destructor);
 291
 292         return true;
 293 }
 294
 295
 296 /*
 297   wrapped connection to a ldb database
 298   to close just talloc_free() the returned ldb_context
 299
 300   TODO:  We need an error_string parameter
 301  */
 302  struct ldb_context *ldb_wrap_connect(TALLOC_CTX *mem_ctx,
 303                                       struct tevent_context *ev,
 304                                       struct loadparm_context *lp_ctx,
 305                                       const char *url,
 306                                       struct auth_session_info *session_info,
 307                                       struct cli_credentials *credentials,
 308                                       unsigned int flags)
 309 {
 310         struct ldb_context *ldb;
 311         int ret;
 312
 313         /*
 314          * Unlike samdb_connect_url() do not try and cache the LDB
 315          * handle, get a new one each time.  Only sam.ldb is
 316          * punitively expensive to open and helpful caches like this
 317          * cause challenges (such as if the value for 'private dir'
 318          * changes).
 319          */
 320
 321         ldb = samba_ldb_init(mem_ctx, ev, lp_ctx, session_info, credentials);
 322
 323         if (ldb == NULL)
 324                 return NULL;
 325
 326         ret = samba_ldb_connect(ldb, lp_ctx, url, flags);
 327         if (ret != LDB_SUCCESS) {
 328                 talloc_free(ldb);
 329                 return NULL;
 330         }
 331
 332         DEBUG(3,("ldb_wrap open of %s\n", url));
 333
 334         return ldb;
 335 }
 336
 337 /*
 338   call tdb_reopen_all() in case there is a TDB open so we are
 339   not blocked from re-opening it inside ldb_tdb.
 340 */
 341  void ldb_wrap_fork_hook(void)
 342 {
 343         if (tdb_reopen_all(1) != 0) {
 344                 smb_panic("tdb_reopen_all failed\n");
 345         }
 346 }
 347
 348  char *ldb_relative_path(struct ldb_context *ldb,
 349                          TALLOC_CTX *mem_ctx,
 350                          const char *name)
 351 {
 352         const char *base_url =
 353                 (const char *)ldb_get_opaque(ldb, "ldb_url");
 354         char *path, *p, *full_name;
 355         if (name == NULL) {
 356                 return NULL;
 357         }
 358         if (strncmp("tdb://", base_url, 6) == 0) {
 359                 base_url = base_url+6;
 360         } else if (strncmp("mdb://", base_url, 6) == 0) {
 361                 base_url = base_url+6;
 362         } else if (strncmp("ldb://", base_url, 6) == 0) {
 363                 base_url = base_url+6;
 364         }
 365         path = talloc_strdup(mem_ctx, base_url);
 366         if (path == NULL) {
 367                 return NULL;
 368         }
 369         if ( (p = strrchr(path, '/')) != NULL) {
 370                 p[0] = '\0';
 371                 full_name = talloc_asprintf(mem_ctx, "%s/%s", path, name);
 372         } else {
 373                 full_name = talloc_asprintf(mem_ctx, "./%s", name);
 374         }
 375         talloc_free(path);
 376         return full_name;
 377 }