source4/lib/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 "lib/ldb/include/ldb.h"
  32 #include "lib/ldb/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 "../tdb/include/tdb.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   see if two database opens are equivalent
  99  */
 100 static bool ldb_wrap_same_context(const struct ldb_wrap_context *c1,
 101                                   const struct ldb_wrap_context *c2)
 102 {
 103         return (c1->ev == c2->ev &&
 104                 c1->lp_ctx == c2->lp_ctx &&
 105                 c1->session_info == c2->session_info &&
 106                 c1->credentials == c2->credentials &&
 107                 c1->flags == c2->flags &&
 108                 (c1->url == c2->url || strcmp(c1->url, c2->url) == 0));
 109 }
 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   wrapped connection to a ldb database
 122   to close just talloc_free() the returned ldb_context
 123
 124   TODO:  We need an error_string parameter
 125  */
 126 struct ldb_context *ldb_wrap_connect(TALLOC_CTX *mem_ctx,
 127                                      struct tevent_context *ev,
 128                                      struct loadparm_context *lp_ctx,
 129                                      const char *url,
 130                                      struct auth_session_info *session_info,
 131                                      struct cli_credentials *credentials,
 132                                      unsigned int flags)
 133 {
 134         struct ldb_context *ldb;
 135         int ret;
 136         char *real_url = NULL;
 137         struct ldb_wrap *w;
 138         struct ldb_wrap_context c;
 139
 140         c.url          = url;
 141         c.ev           = ev;
 142         c.lp_ctx       = lp_ctx;
 143         c.session_info = session_info;
 144         c.credentials  = credentials;
 145         c.flags        = flags;
 146
 147         /* see if we can re-use an existing ldb */
 148         for (w=ldb_wrap_list; w; w=w->next) {
 149                 if (ldb_wrap_same_context(&c, &w->context)) {
 150                         return talloc_reference(mem_ctx, w->ldb);
 151                 }
 152         }
 153
 154         /* we want to use the existing event context if possible. This
 155            relies on the fact that in smbd, everything is a child of
 156            the main event_context */
 157         if (ev == NULL) {
 158                 return NULL;
 159         }
 160
 161         ldb = ldb_init(mem_ctx, ev);
 162         if (ldb == NULL) {
 163                 return NULL;
 164         }
 165
 166         ldb_set_modules_dir(ldb,
 167                             talloc_asprintf(ldb,
 168                                             "%s/ldb",
 169                                             lp_modulesdir(lp_ctx)));
 170
 171         if (ldb_set_opaque(ldb, "sessionInfo", session_info)) {
 172                 talloc_free(ldb);
 173                 return NULL;
 174         }
 175
 176         if (ldb_set_opaque(ldb, "credentials", credentials)) {
 177                 talloc_free(ldb);
 178                 return NULL;
 179         }
 180
 181         if (ldb_set_opaque(ldb, "loadparm", lp_ctx)) {
 182                 talloc_free(ldb);
 183                 return NULL;
 184         }
 185
 186         /* This must be done before we load the schema, as these
 187          * handlers for objectSid and objectGUID etc must take
 188          * precedence over the 'binary attribute' declaration in the
 189          * schema */
 190         ret = ldb_register_samba_handlers(ldb);
 191         if (ret == -1) {
 192                 talloc_free(ldb);
 193                 return NULL;
 194         }
 195
 196         if (lp_ctx != NULL && strcmp(lp_sam_url(lp_ctx), url) == 0) {
 197                 dsdb_set_global_schema(ldb);
 198         }
 199
 200         ldb_set_debug(ldb, ldb_wrap_debug, NULL);
 201
 202         ldb_set_utf8_fns(ldb, NULL, wrap_casefold);
 203
 204         real_url = private_path(ldb, lp_ctx, url);
 205         if (real_url == NULL) {
 206                 talloc_free(ldb);
 207                 return NULL;
 208         }
 209
 210         /* allow admins to force non-sync ldb for all databases */
 211         if (lp_parm_bool(lp_ctx, NULL, "ldb", "nosync", false)) {
 212                 flags |= LDB_FLG_NOSYNC;
 213         }
 214
 215         if (DEBUGLVL(10)) {
 216                 flags |= LDB_FLG_ENABLE_TRACING;
 217         }
 218
 219         /* we usually want Samba databases to be private. If we later
 220            find we need one public, we will need to add a parameter to
 221            ldb_wrap_connect() */
 222         ldb_set_create_perms(ldb, 0600);
 223
 224         ret = ldb_connect(ldb, real_url, flags, NULL);
 225         if (ret != LDB_SUCCESS) {
 226                 talloc_free(ldb);
 227                 return NULL;
 228         }
 229
 230         /* setup for leak detection */
 231         ldb_set_opaque(ldb, "wrap_url", real_url);
 232
 233         /* add to the list of open ldb contexts */
 234         w = talloc(ldb, struct ldb_wrap);
 235         if (w == NULL) {
 236                 talloc_free(ldb);
 237                 return NULL;
 238         }
 239
 240         w->context = c;
 241         w->context.url = talloc_strdup(w, url);
 242         if (w->context.url == NULL) {
 243                 talloc_free(ldb);
 244                 return NULL;
 245         }
 246
 247         w->ldb = ldb;
 248
 249         DLIST_ADD(ldb_wrap_list, w);
 250
 251         /* make the resulting schema global */
 252         if (lp_ctx != NULL && strcmp(lp_sam_url(lp_ctx), url) == 0) {
 253                 struct dsdb_schema *schema = dsdb_get_schema(ldb, NULL);
 254                 if (schema) {
 255                         dsdb_make_schema_global(ldb, schema);
 256                 }
 257         }
 258
 259         DEBUG(3,("ldb_wrap open of %s\n", url));
 260
 261         talloc_set_destructor(w, ldb_wrap_destructor);
 262
 263         return ldb;
 264 }
 265
 266 /*
 267   when we fork() we need to make sure that any open ldb contexts have
 268   any open transactions cancelled
 269  */
 270 void ldb_wrap_fork_hook(void)
 271 {
 272         struct ldb_wrap *w;
 273
 274         for (w=ldb_wrap_list; w; w=w->next) {
 275                 if (ldb_transaction_cancel_noerr(w->ldb) != LDB_SUCCESS) {
 276                         smb_panic("Failed to cancel child transactions\n");
 277                 }
 278         }
 279
 280         if (tdb_reopen_all(1) == -1) {
 281                 smb_panic("tdb_reopen_all failed\n");
 282         }
 283 }
 284