source3/lib/ldb/ldb_tdb/ldb_tdb_wrap.c

   1 /*
   2    ldb database library
   3
   4    Copyright (C) Andrew Tridgell  2005
   5
   6      ** NOTE! The following LGPL license applies to the ldb
   7      ** library. This does NOT imply that all of Samba is released
   8      ** under the LGPL
   9
  10    This library is free software; you can redistribute it and/or
  11    modify it under the terms of the GNU Lesser General Public
  12    License as published by the Free Software Foundation; either
  13    version 3 of the License, or (at your option) any later version.
  14
  15    This library is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18    Lesser General Public License for more details.
  19
  20    You should have received a copy of the GNU Lesser General Public
  21    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "ldb/include/includes.h"
  26
  27 #include "ldb/ldb_tdb/ldb_tdb.h"
  28
  29 /*
  30   the purpose of this code is to work around the braindead posix locking
  31   rules, to allow us to have a ldb open more than once while allowing
  32   locking to work
  33 */
  34
  35 struct ltdb_wrap {
  36         struct ltdb_wrap *next, *prev;
  37         struct tdb_context *tdb;
  38         dev_t device;
  39         ino_t inode;
  40 };
  41
  42 static struct ltdb_wrap *tdb_list;
  43
  44 /* destroy the last connection to a tdb */
  45 static int ltdb_wrap_destructor(struct ltdb_wrap *w)
  46 {
  47         tdb_close(w->tdb);
  48         DLIST_REMOVE(tdb_list, w);
  49         return 0;
  50 }
  51
  52 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
  53 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
  54 {
  55         va_list ap;
  56         const char *name = tdb_name(tdb);
  57         struct ldb_context *ldb = talloc_get_type(tdb_get_logging_private(tdb), struct ldb_context);
  58         enum ldb_debug_level ldb_level;
  59         char *message;
  60         va_start(ap, fmt);
  61         message = talloc_vasprintf(ldb, fmt, ap);
  62         va_end(ap);
  63
  64         switch (level) {
  65         case TDB_DEBUG_FATAL:
  66                 ldb_level = LDB_DEBUG_FATAL;
  67                 break;
  68         case TDB_DEBUG_ERROR:
  69                 ldb_level = LDB_DEBUG_ERROR;
  70                 break;
  71         case TDB_DEBUG_WARNING:
  72                 ldb_level = LDB_DEBUG_WARNING;
  73                 break;
  74         case TDB_DEBUG_TRACE:
  75                 ldb_level = LDB_DEBUG_TRACE;
  76                 break;
  77         default:
  78                 ldb_level = LDB_DEBUG_FATAL;
  79         }
  80
  81         ldb_debug(ldb, ldb_level, "ltdb: tdb(%s): %s", name, message);
  82         talloc_free(message);
  83 }
  84
  85 /*
  86   wrapped connection to a tdb database. The caller should _not_ free
  87   this as it is not a talloc structure (as tdb does not use talloc
  88   yet). It will auto-close when the caller frees the mem_ctx that is
  89   passed to this call
  90  */
  91 struct tdb_context *ltdb_wrap_open(TALLOC_CTX *mem_ctx,
  92                                    const char *path, int hash_size,
  93                                    int tdb_flags,
  94                                    int open_flags, mode_t mode,
  95                                    struct ldb_context *ldb)
  96 {
  97         struct ltdb_wrap *w;
  98         struct stat st;
  99         struct tdb_logging_context log_ctx;
 100
 101         log_ctx.log_fn = ltdb_log_fn;
 102         log_ctx.log_private = ldb;
 103
 104         if (stat(path, &st) == 0) {
 105                 for (w=tdb_list;w;w=w->next) {
 106                         if (st.st_dev == w->device && st.st_ino == w->inode) {
 107                                 if (!talloc_reference(mem_ctx, w)) {
 108                                         return NULL;
 109                                 }
 110                                 return w->tdb;
 111                         }
 112                 }
 113         }
 114
 115         w = talloc(mem_ctx, struct ltdb_wrap);
 116         if (w == NULL) {
 117                 return NULL;
 118         }
 119
 120         w->tdb = tdb_open_ex(path, hash_size, tdb_flags, open_flags, mode, &log_ctx, NULL);
 121         if (w->tdb == NULL) {
 122                 talloc_free(w);
 123                 return NULL;
 124         }
 125
 126         if (fstat(tdb_fd(w->tdb), &st) != 0) {
 127                 tdb_close(w->tdb);
 128                 talloc_free(w);
 129                 return NULL;
 130         }
 131
 132         w->device = st.st_dev;
 133         w->inode  = st.st_ino;
 134
 135         talloc_set_destructor(w, ltdb_wrap_destructor);
 136
 137         DLIST_ADD(tdb_list, w);
 138
 139         return w->tdb;
 140 }
 141