lib/util/tdb_wrap.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    TDB wrap functions
   4
   5    Copyright (C) Andrew Tridgell 2004
   6    Copyright (C) Jelmer Vernooij <jelmer@samba.org> 2007
   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 #include "includes.h"
  23 #include "lib/util/dlinklist.h"
  24 #include "lib/util/tdb_wrap.h"
  25 #include "lib/param/param.h"
  26
  27 /* FIXME: TDB2 does this internally, so no need to wrap multiple opens! */
  28 #if BUILD_TDB2
  29 static void tdb_wrap_log(struct tdb_context *tdb,
  30                          enum tdb_log_level level,
  31                          enum TDB_ERROR ecode,
  32                          const char *message,
  33                          void *unused)
  34 {
  35         int dl;
  36         const char *name = tdb_name(tdb);
  37
  38         switch (level) {
  39         case TDB_LOG_USE_ERROR:
  40         case TDB_LOG_ERROR:
  41                 dl = 0;
  42                 break;
  43         case TDB_LOG_WARNING:
  44                 dl = 2;
  45                 break;
  46         default:
  47                 dl = 0;
  48         }
  49
  50         DEBUG(dl, ("tdb(%s):%s: %s", name ? name : "unnamed",
  51                    tdb_errorstr(ecode), message));
  52 }
  53 #else
  54 /*
  55  Log tdb messages via DEBUG().
  56 */
  57 static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level,
  58                          const char *format, ...) PRINTF_ATTRIBUTE(3,4);
  59
  60 static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level,
  61                          const char *format, ...)
  62 {
  63         va_list ap;
  64         char *ptr = NULL;
  65         int debuglevel = 0;
  66         int ret;
  67
  68         switch (level) {
  69         case TDB_DEBUG_FATAL:
  70                 debuglevel = 0;
  71                 break;
  72         case TDB_DEBUG_ERROR:
  73                 debuglevel = 1;
  74                 break;
  75         case TDB_DEBUG_WARNING:
  76                 debuglevel = 2;
  77                 break;
  78         case TDB_DEBUG_TRACE:
  79                 debuglevel = 5;
  80                 break;
  81         default:
  82                 debuglevel = 0;
  83         }
  84
  85         va_start(ap, format);
  86         ret = vasprintf(&ptr, format, ap);
  87         va_end(ap);
  88
  89         if (ret != -1) {
  90                 const char *name = tdb_name(tdb);
  91                 DEBUG(debuglevel, ("tdb(%s): %s", name ? name : "unnamed", ptr));
  92                 free(ptr);
  93         }
  94 }
  95 #endif
  96
  97 struct tdb_wrap_private {
  98         struct tdb_context *tdb;
  99         const char *name;
 100         struct tdb_wrap_private *next, *prev;
 101 };
 102
 103 static struct tdb_wrap_private *tdb_list;
 104
 105 /* destroy the last connection to a tdb */
 106 static int tdb_wrap_private_destructor(struct tdb_wrap_private *w)
 107 {
 108         tdb_close(w->tdb);
 109         DLIST_REMOVE(tdb_list, w);
 110         return 0;
 111 }
 112
 113 static struct tdb_wrap_private *tdb_wrap_private_open(TALLOC_CTX *mem_ctx,
 114                                                       const char *name,
 115                                                       int hash_size,
 116                                                       int tdb_flags,
 117                                                       int open_flags,
 118                                                       mode_t mode,
 119                                                       struct loadparm_context *lp_ctx)
 120 {
 121         struct tdb_wrap_private *result;
 122
 123         result = talloc(mem_ctx, struct tdb_wrap_private);
 124         if (result == NULL) {
 125                 return NULL;
 126         }
 127         result->name = talloc_strdup(result, name);
 128         if (result->name == NULL) {
 129                 goto fail;
 130         }
 131
 132         if (!lpcfg_use_mmap(lp_ctx)) {
 133                 tdb_flags |= TDB_NOMMAP;
 134         }
 135
 136         if ((hash_size == 0) && (name != NULL)) {
 137                 const char *base;
 138                 base = strrchr_m(name, '/');
 139
 140                 if (base != NULL) {
 141                         base += 1;
 142                 } else {
 143                         base = name;
 144                 }
 145                 hash_size = lpcfg_parm_int(lp_ctx, NULL, "tdb_hashsize", base, 0);
 146         }
 147
 148         result->tdb = tdb_open_compat(name, hash_size, tdb_flags,
 149                                       open_flags, mode, tdb_wrap_log, NULL);
 150         if (result->tdb == NULL) {
 151                 goto fail;
 152         }
 153         talloc_set_destructor(result, tdb_wrap_private_destructor);
 154         DLIST_ADD(tdb_list, result);
 155         return result;
 156
 157 fail:
 158         TALLOC_FREE(result);
 159         return NULL;
 160 }
 161
 162 /*
 163   wrapped connection to a tdb database
 164   to close just talloc_free() the tdb_wrap pointer
 165  */
 166 struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
 167                                const char *name, int hash_size, int tdb_flags,
 168                                int open_flags, mode_t mode,
 169                                struct loadparm_context *lp_ctx)
 170 {
 171         struct tdb_wrap *result;
 172         struct tdb_wrap_private *w;
 173
 174         result = talloc(mem_ctx, struct tdb_wrap);
 175         if (result == NULL) {
 176                 return NULL;
 177         }
 178
 179         for (w=tdb_list;w;w=w->next) {
 180                 if (strcmp(name, w->name) == 0) {
 181                         break;
 182                 }
 183         }
 184
 185         if (w == NULL) {
 186                 w = tdb_wrap_private_open(result, name, hash_size, tdb_flags,
 187                                           open_flags, mode, lp_ctx);
 188         } else {
 189                 /*
 190                  * Correctly use talloc_reference: The tdb will be
 191                  * closed when "w" is being freed. The caller never
 192                  * sees "w", so an incorrect use of talloc_free(w)
 193                  * instead of calling talloc_unlink is not possible.
 194                  * To avoid having to refcount ourselves, "w" will
 195                  * have multiple parents that hang off all the
 196                  * tdb_wrap's being returned from here. Those parents
 197                  * can be freed without problem.
 198                  */
 199                 if (talloc_reference(result, w) == NULL) {
 200                         goto fail;
 201                 }
 202         }
 203         if (w == NULL) {
 204                 goto fail;
 205         }
 206         result->tdb = w->tdb;
 207         return result;
 208 fail:
 209         TALLOC_FREE(result);
 210         return NULL;
 211 }
 212