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 2 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, write to the Free Software
  22    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23 */
  24
  25 #include "includes.h"
  26 #include "ldb/include/includes.h"
  27
  28 #include "ldb/ldb_tdb/ldb_tdb.h"
  29
  30 /*
  31   the purpose of this code is to work around the braindead posix locking
  32   rules, to allow us to have a ldb open more than once while allowing
  33   locking to work
  34 */
  35
  36 struct ltdb_wrap {
  37         struct ltdb_wrap *next, *prev;
  38         struct tdb_context *tdb;
  39         dev_t device;
  40         ino_t inode;
  41 };
  42
  43 static struct ltdb_wrap *tdb_list;
  44
  45 /* destroy the last connection to a tdb */
  46 static int ltdb_wrap_destructor(struct ltdb_wrap *w)
  47 {
  48         tdb_close(w->tdb);
  49         if (w->next) {
  50                 w->next->prev = w->prev;
  51         }
  52         if (w->prev) {
  53                 w->prev->next = w->next;
  54         }
  55         if (w == tdb_list) {
  56                 tdb_list = w->next;
  57         }
  58         return 0;
  59 }
  60
  61 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
  62 static void ltdb_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
  63 {
  64         va_list ap;
  65         const char *name = tdb_name(tdb);
  66         struct ldb_context *ldb = talloc_get_type(tdb_get_logging_private(tdb), struct ldb_context);
  67         enum ldb_debug_level ldb_level;
  68         char *message;
  69         va_start(ap, fmt);
  70         message = talloc_vasprintf(ldb, fmt, ap);
  71         va_end(ap);
  72
  73         switch (level) {
  74         case TDB_DEBUG_FATAL:
  75                 ldb_level = LDB_DEBUG_FATAL;
  76                 break;
  77         case TDB_DEBUG_ERROR:
  78                 ldb_level = LDB_DEBUG_ERROR;
  79                 break;
  80         case TDB_DEBUG_WARNING:
  81                 ldb_level = LDB_DEBUG_WARNING;
  82                 break;
  83         case TDB_DEBUG_TRACE:
  84                 ldb_level = LDB_DEBUG_TRACE;
  85                 break;
  86         default:
  87                 ldb_level = LDB_DEBUG_FATAL;
  88         }
  89
  90         ldb_debug(ldb, ldb_level, "ltdb: tdb(%s): %s", name, message);
  91         talloc_free(message);
  92 }
  93
  94 /*
  95   wrapped connection to a tdb database. The caller should _not_ free
  96   this as it is not a talloc structure (as tdb does not use talloc
  97   yet). It will auto-close when the caller frees the mem_ctx that is
  98   passed to this call
  99  */
 100 struct tdb_context *ltdb_wrap_open(TALLOC_CTX *mem_ctx,
 101                                    const char *path, int hash_size,
 102                                    int tdb_flags,
 103                                    int open_flags, mode_t mode,
 104                                    struct ldb_context *ldb)
 105 {
 106         struct ltdb_wrap *w;
 107         struct stat st;
 108         struct tdb_logging_context log_ctx;
 109
 110         log_ctx.log_fn = ltdb_log_fn;
 111         log_ctx.log_private = ldb;
 112
 113         if (stat(path, &st) == 0) {
 114                 for (w=tdb_list;w;w=w->next) {
 115                         if (st.st_dev == w->device && st.st_ino == w->inode) {
 116                                 if (!talloc_reference(mem_ctx, w)) {
 117                                         return NULL;
 118                                 }
 119                                 return w->tdb;
 120                         }
 121                 }
 122         }
 123
 124         w = talloc(mem_ctx, struct ltdb_wrap);
 125         if (w == NULL) {
 126                 return NULL;
 127         }
 128
 129         w->tdb = tdb_open_ex(path, hash_size, tdb_flags, open_flags, mode, &log_ctx, NULL);
 130         if (w->tdb == NULL) {
 131                 talloc_free(w);
 132                 return NULL;
 133         }
 134
 135         if (fstat(tdb_fd(w->tdb), &st) != 0) {
 136                 tdb_close(w->tdb);
 137                 talloc_free(w);
 138                 return NULL;
 139         }
 140
 141         w->device = st.st_dev;
 142         w->inode  = st.st_ino;
 143
 144         talloc_set_destructor(w, ltdb_wrap_destructor);
 145
 146         w->next = tdb_list;
 147         w->prev = NULL;
 148         if (tdb_list) {
 149                 tdb_list->prev = w;
 150         }
 151         tdb_list = w;
 152
 153         return w->tdb;
 154 }
 155