ctdb/lib/util/db_wrap.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    database wrap functions
   5
   6    Copyright (C) Andrew Tridgell 2004
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 /*
  23   the stupidity of the unix fcntl locking design forces us to never
  24   allow a database file to be opened twice in the same process. These
  25   wrappers provide convenient access to a tdb or ldb, taking advantage
  26   of talloc destructors to ensure that only a single open is done
  27 */
  28
  29 #include "includes.h"
  30 #include "lib/util/dlinklist.h"
  31 #include "tdb.h"
  32 #include "db_wrap.h"
  33
  34 static struct tdb_wrap *tdb_list;
  35
  36
  37
  38 /* destroy the last connection to a tdb */
  39 static int tdb_wrap_destructor(struct tdb_wrap *w)
  40 {
  41         tdb_close(w->tdb);
  42         DLIST_REMOVE(tdb_list, w);
  43         return 0;
  44 }
  45
  46 static void log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
  47 {
  48         if (level <= TDB_DEBUG_ERROR) {
  49                 va_list ap;
  50                 this_log_level = level;
  51                 char newfmt[strlen(tdb_name(tdb)) + 1 + strlen(fmt) + 1];
  52                 sprintf(newfmt, "%s:%s", tdb_name(tdb), fmt);
  53                 va_start(ap, fmt);
  54                 do_debug_v(newfmt, ap);
  55                 va_end(ap);
  56         }
  57 }
  58
  59
  60 /*
  61   wrapped connection to a tdb database
  62   to close just talloc_free() the tdb_wrap pointer
  63  */
  64 struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
  65                                const char *name, int hash_size, int tdb_flags,
  66                                int open_flags, mode_t mode)
  67 {
  68         struct tdb_wrap *w;
  69         struct tdb_logging_context log_ctx;
  70
  71         log_ctx.log_fn = log_fn;
  72         log_ctx.log_private = NULL;
  73
  74         for (w=tdb_list;w;w=w->next) {
  75                 if (strcmp(name, w->name) == 0) {
  76                         return talloc_reference(mem_ctx, w);
  77                 }
  78         }
  79
  80         w = talloc(mem_ctx, struct tdb_wrap);
  81         if (w == NULL) {
  82                 return NULL;
  83         }
  84
  85         w->name = talloc_strdup(w, name);
  86         if (w->name == NULL) {
  87                 talloc_free(w);
  88                 return NULL;
  89         }
  90
  91         w->tdb = tdb_open_ex(name, hash_size, tdb_flags,
  92                              open_flags, mode, &log_ctx, NULL);
  93         if (w->tdb == NULL) {
  94                 talloc_free(w);
  95                 return NULL;
  96         }
  97
  98         talloc_set_destructor(w, tdb_wrap_destructor);
  99
 100         DLIST_ADD(tdb_list, w);
 101
 102         return w;
 103 }