source/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         if (w->next) {
  49                 w->next->prev = w->prev;
  50         }
  51         if (w->prev) {
  52                 w->prev->next = w->next;
  53         }
  54         if (w == tdb_list) {
  55                 tdb_list = w->next;
  56         }
  57         return 0;
  58 }
  59
  60 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
  61 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
  62 {
  63         va_list ap;
  64         const char *name = tdb_name(tdb);
  65         struct ldb_context *ldb = talloc_get_type(tdb_get_logging_private(tdb), struct ldb_context);
  66         enum ldb_debug_level ldb_level;
  67         char *message;
  68         va_start(ap, fmt);
  69         message = talloc_vasprintf(ldb, fmt, ap);
  70         va_end(ap);
  71
  72         switch (level) {
  73         case TDB_DEBUG_FATAL:
  74                 ldb_level = LDB_DEBUG_FATAL;
  75                 break;
  76         case TDB_DEBUG_ERROR:
  77                 ldb_level = LDB_DEBUG_ERROR;
  78                 break;
  79         case TDB_DEBUG_WARNING:
  80                 ldb_level = LDB_DEBUG_WARNING;
  81                 break;
  82         case TDB_DEBUG_TRACE:
  83                 ldb_level = LDB_DEBUG_TRACE;
  84                 break;
  85         default:
  86                 ldb_level = LDB_DEBUG_FATAL;
  87         }
  88
  89         ldb_debug(ldb, ldb_level, "ltdb: tdb(%s): %s", name, message);
  90         talloc_free(message);
  91 }
  92
  93 /*
  94   wrapped connection to a tdb database. The caller should _not_ free
  95   this as it is not a talloc structure (as tdb does not use talloc
  96   yet). It will auto-close when the caller frees the mem_ctx that is
  97   passed to this call
  98  */
  99 struct tdb_context *ltdb_wrap_open(TALLOC_CTX *mem_ctx,
 100                                    const char *path, int hash_size,
 101                                    int tdb_flags,
 102                                    int open_flags, mode_t mode,
 103                                    struct ldb_context *ldb)
 104 {
 105         struct ltdb_wrap *w;
 106         struct stat st;
 107         struct tdb_logging_context log_ctx;
 108
 109         log_ctx.log_fn = ltdb_log_fn;
 110         log_ctx.log_private = ldb;
 111
 112         if (stat(path, &st) == 0) {
 113                 for (w=tdb_list;w;w=w->next) {
 114                         if (st.st_dev == w->device && st.st_ino == w->inode) {
 115                                 if (!talloc_reference(mem_ctx, w)) {
 116                                         return NULL;
 117                                 }
 118                                 return w->tdb;
 119                         }
 120                 }
 121         }
 122
 123         w = talloc(mem_ctx, struct ltdb_wrap);
 124         if (w == NULL) {
 125                 return NULL;
 126         }
 127
 128         w->tdb = tdb_open_ex(path, hash_size, tdb_flags, open_flags, mode, &log_ctx, NULL);
 129         if (w->tdb == NULL) {
 130                 talloc_free(w);
 131                 return NULL;
 132         }
 133
 134         if (fstat(tdb_fd(w->tdb), &st) != 0) {
 135                 tdb_close(w->tdb);
 136                 talloc_free(w);
 137                 return NULL;
 138         }
 139
 140         w->device = st.st_dev;
 141         w->inode  = st.st_ino;
 142
 143         talloc_set_destructor(w, ltdb_wrap_destructor);
 144
 145         w->next = tdb_list;
 146         w->prev = NULL;
 147         if (tdb_list) {
 148                 tdb_list->prev = w;
 149         }
 150         tdb_list = w;
 151
 152         return w->tdb;
 153 }
 154