source4/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 /*
  28   the purpose of this code is to work around the braindead posix locking
  29   rules, to allow us to have a ldb open more than once while allowing
  30   locking to work
  31 */
  32
  33 struct ltdb_wrap {
  34         struct ltdb_wrap *next, *prev;
  35         struct tdb_context *tdb;
  36         dev_t device;
  37         ino_t inode;
  38 };
  39
  40 static struct ltdb_wrap *tdb_list;
  41
  42 /* destroy the last connection to a tdb */
  43 static int ltdb_wrap_destructor(struct ltdb_wrap *w)
  44 {
  45         tdb_close(w->tdb);
  46         DLIST_REMOVE(tdb_list, w);
  47         return 0;
  48 }
  49
  50 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
  51 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
  52 {
  53         va_list ap;
  54         const char *name = tdb_name(tdb);
  55         struct ldb_context *ldb = talloc_get_type(tdb_get_logging_private(tdb), struct ldb_context);
  56         enum ldb_debug_level ldb_level;
  57         char *message;
  58
  59         if (ldb == NULL)
  60                 return;
  61
  62         va_start(ap, fmt);
  63         message = talloc_vasprintf(ldb, fmt, ap);
  64         va_end(ap);
  65
  66         switch (level) {
  67         case TDB_DEBUG_FATAL:
  68                 ldb_level = LDB_DEBUG_FATAL;
  69                 break;
  70         case TDB_DEBUG_ERROR:
  71                 ldb_level = LDB_DEBUG_ERROR;
  72                 break;
  73         case TDB_DEBUG_WARNING:
  74                 ldb_level = LDB_DEBUG_WARNING;
  75                 break;
  76         case TDB_DEBUG_TRACE:
  77                 ldb_level = LDB_DEBUG_TRACE;
  78                 break;
  79         default:
  80                 ldb_level = LDB_DEBUG_FATAL;
  81         }
  82
  83         ldb_debug(ldb, ldb_level, "ltdb: tdb(%s): %s", name, message);
  84         talloc_free(message);
  85 }
  86
  87 /*
  88   wrapped connection to a tdb database. The caller should _not_ free
  89   this as it is not a talloc structure (as tdb does not use talloc
  90   yet). It will auto-close when the caller frees the mem_ctx that is
  91   passed to this call
  92  */
  93 struct tdb_context *ltdb_wrap_open(TALLOC_CTX *mem_ctx,
  94                                    const char *path, int hash_size,
  95                                    int tdb_flags,
  96                                    int open_flags, mode_t mode,
  97                                    struct ldb_context *ldb)
  98 {
  99         struct ltdb_wrap *w;
 100         struct stat st;
 101         struct tdb_logging_context log_ctx;
 102
 103         log_ctx.log_fn = ltdb_log_fn;
 104         log_ctx.log_private = ldb;
 105
 106         if (stat(path, &st) == 0) {
 107                 for (w=tdb_list;w;w=w->next) {
 108                         if (st.st_dev == w->device && st.st_ino == w->inode) {
 109                                 if (!talloc_reference(mem_ctx, w)) {
 110                                         return NULL;
 111                                 }
 112                                 return w->tdb;
 113                         }
 114                 }
 115         }
 116
 117         w = talloc(mem_ctx, struct ltdb_wrap);
 118         if (w == NULL) {
 119                 return NULL;
 120         }
 121
 122         w->tdb = tdb_open_ex(path, hash_size, tdb_flags, open_flags, mode, &log_ctx, NULL);
 123         if (w->tdb == NULL) {
 124                 talloc_free(w);
 125                 return NULL;
 126         }
 127
 128         if (fstat(tdb_fd(w->tdb), &st) != 0) {
 129                 tdb_close(w->tdb);
 130                 talloc_free(w);
 131                 return NULL;
 132         }
 133
 134         w->device = st.st_dev;
 135         w->inode  = st.st_ino;
 136
 137         talloc_set_destructor(w, ltdb_wrap_destructor);
 138
 139         DLIST_ADD(tdb_list, w);
 140
 141         return w->tdb;
 142 }
 143