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 "ldb_tdb.h"
  25 #include "dlinklist.h"
  26
  27 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
  28 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
  29 {
  30         va_list ap;
  31         const char *name = tdb_name(tdb);
  32         struct ldb_context *ldb = talloc_get_type(tdb_get_logging_private(tdb), struct ldb_context);
  33         enum ldb_debug_level ldb_level;
  34         char *message;
  35
  36         if (ldb == NULL)
  37                 return;
  38
  39         va_start(ap, fmt);
  40         message = talloc_vasprintf(ldb, fmt, ap);
  41         va_end(ap);
  42
  43         switch (level) {
  44         case TDB_DEBUG_FATAL:
  45                 ldb_level = LDB_DEBUG_FATAL;
  46                 break;
  47         case TDB_DEBUG_ERROR:
  48                 ldb_level = LDB_DEBUG_ERROR;
  49                 break;
  50         case TDB_DEBUG_WARNING:
  51                 ldb_level = LDB_DEBUG_WARNING;
  52                 break;
  53         case TDB_DEBUG_TRACE:
  54                 ldb_level = LDB_DEBUG_TRACE;
  55                 break;
  56         default:
  57                 ldb_level = LDB_DEBUG_FATAL;
  58         }
  59
  60         ldb_debug(ldb, ldb_level, "ltdb: tdb(%s): %s", name, message);
  61         talloc_free(message);
  62 }
  63
  64 /*
  65   the purpose of this code is to work around the braindead posix locking
  66   rules, to allow us to have a ldb open more than once while allowing
  67   locking to work
  68
  69   TDB2 handles multiple opens, so we don't have this problem there.
  70 */
  71
  72 struct ltdb_wrap {
  73         struct ltdb_wrap *next, *prev;
  74         struct tdb_context *tdb;
  75         dev_t device;
  76         ino_t inode;
  77 };
  78
  79 static struct ltdb_wrap *tdb_list;
  80
  81 /* destroy the last connection to a tdb */
  82 static int ltdb_wrap_destructor(struct ltdb_wrap *w)
  83 {
  84         tdb_close(w->tdb);
  85         DLIST_REMOVE(tdb_list, w);
  86         return 0;
  87 }
  88
  89 /*
  90   wrapped connection to a tdb database. The caller should _not_ free
  91   this as it is not a talloc structure (as tdb does not use talloc
  92   yet). It will auto-close when the caller frees the mem_ctx that is
  93   passed to this call
  94  */
  95 struct tdb_context *ltdb_wrap_open(TALLOC_CTX *mem_ctx,
  96                                    const char *path, int hash_size,
  97                                    int tdb_flags,
  98                                    int open_flags, mode_t mode,
  99                                    struct ldb_context *ldb)
 100 {
 101         struct ltdb_wrap *w;
 102         struct tdb_logging_context lctx;
 103         struct stat st;
 104
 105         if (stat(path, &st) == 0) {
 106                 for (w=tdb_list;w;w=w->next) {
 107                         if (st.st_dev == w->device && st.st_ino == w->inode) {
 108                                 if (!talloc_reference(mem_ctx, w)) {
 109                                         return NULL;
 110                                 }
 111                                 return w->tdb;
 112                         }
 113                 }
 114         }
 115
 116         w = talloc(mem_ctx, struct ltdb_wrap);
 117         if (w == NULL) {
 118                 return NULL;
 119         }
 120
 121         lctx.log_fn = ltdb_log_fn;
 122         lctx.log_private = ldb;
 123         w->tdb = tdb_open_ex(path, hash_size, tdb_flags, open_flags, mode,
 124                              &lctx, NULL);
 125         if (w->tdb == NULL) {
 126                 talloc_free(w);
 127                 return NULL;
 128         }
 129
 130         if (fstat(tdb_fd(w->tdb), &st) != 0) {
 131                 tdb_close(w->tdb);
 132                 talloc_free(w);
 133                 return NULL;
 134         }
 135
 136         w->device = st.st_dev;
 137         w->inode  = st.st_ino;
 138
 139         talloc_set_destructor(w, ltdb_wrap_destructor);
 140
 141         DLIST_ADD(tdb_list, w);
 142
 143         return w->tdb;
 144 }