source4/lib/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 2 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, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 /*
  24   the stupidity of the unix fcntl locking design forces us to never
  25   allow a database file to be opened twice in the same process. These
  26   wrappers provide convenient access to a tdb or ldb, taking advantage
  27   of talloc destructors to ensure that only a single open is done
  28 */
  29
  30 #include "includes.h"
  31 #include "dlinklist.h"
  32 #include "lib/events/events.h"
  33 #include "lib/tdb/include/tdb.h"
  34 #include "lib/ldb/include/ldb.h"
  35 #include "db_wrap.h"
  36
  37 static struct tdb_wrap *tdb_list;
  38
  39 /*
  40   this is used to catch debug messages from ldb
  41 */
  42 static void ldb_wrap_debug(void *context, enum ldb_debug_level level,
  43                            const char *fmt, va_list ap)  PRINTF_ATTRIBUTE(3,0);
  44
  45 static void ldb_wrap_debug(void *context, enum ldb_debug_level level,
  46                            const char *fmt, va_list ap)
  47 {
  48         char *s = NULL;
  49         if (DEBUGLEVEL < 4 && level > LDB_DEBUG_WARNING) {
  50                 return;
  51         }
  52         vasprintf(&s, fmt, ap);
  53         if (!s) return;
  54         DEBUG(level, ("ldb: %s\n", s));
  55         free(s);
  56 }
  57
  58 /*
  59   wrapped connection to a ldb database
  60   to close just talloc_free() the returned ldb_context
  61  */
  62 struct ldb_context *ldb_wrap_connect(TALLOC_CTX *mem_ctx,
  63                                      const char *url,
  64                                      unsigned int flags,
  65                                      const char *options[])
  66 {
  67         struct ldb_context *ldb;
  68         int ret;
  69         struct event_context *ev;
  70         char *real_url = NULL;
  71
  72         ldb = ldb_init(mem_ctx);
  73         if (ldb == NULL) {
  74                 return NULL;
  75         }
  76
  77         /* we want to use the existing event context if possible. This
  78            relies on the fact that in smbd, everything is a child of
  79            the main event_context */
  80         ev = event_context_find(ldb);
  81
  82         ret = ldb_register_samba_handlers(ldb);
  83         if (ret == -1) {
  84                 talloc_free(ldb);
  85                 return NULL;
  86         }
  87
  88         real_url = private_path(ldb, url);
  89         if (real_url == NULL) {
  90                 talloc_free(ldb);
  91                 return NULL;
  92         }
  93
  94         /* allow admins to force non-sync ldb for all databases */
  95         if (lp_parm_bool(-1, "ldb", "nosync", False)) {
  96                 flags |= LDB_FLG_NOSYNC;
  97         }
  98
  99         ret = ldb_connect(ldb, real_url, flags, options);
 100         if (ret == -1) {
 101                 talloc_free(ldb);
 102                 return NULL;
 103         }
 104
 105         talloc_free(real_url);
 106
 107         ldb_set_debug(ldb, ldb_wrap_debug, NULL);
 108
 109         return ldb;
 110 }
 111
 112
 113 /*
 114  Log tdb messages via DEBUG().
 115 */
 116 static void tdb_wrap_log(TDB_CONTEXT *tdb, int level,
 117                          const char *format, ...) PRINTF_ATTRIBUTE(3,4);
 118
 119 static void tdb_wrap_log(TDB_CONTEXT *tdb, int level,
 120                          const char *format, ...)
 121 {
 122         va_list ap;
 123         char *ptr = NULL;
 124
 125         va_start(ap, format);
 126         vasprintf(&ptr, format, ap);
 127         va_end(ap);
 128
 129         if (ptr != NULL) {
 130                 const char *name = tdb_name(tdb);
 131                 DEBUG(level, ("tdb(%s): %s", name ? name : "unnamed", ptr));
 132                 free(ptr);
 133         }
 134 }
 135
 136
 137 /* destroy the last connection to a tdb */
 138 static int tdb_wrap_destructor(void *ctx)
 139 {
 140         struct tdb_wrap *w = ctx;
 141         tdb_close(w->tdb);
 142         DLIST_REMOVE(tdb_list, w);
 143         return 0;
 144 }
 145
 146 /*
 147   wrapped connection to a tdb database
 148   to close just talloc_free() the tdb_wrap pointer
 149  */
 150 struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
 151                                const char *name, int hash_size, int tdb_flags,
 152                                int open_flags, mode_t mode)
 153 {
 154         struct tdb_wrap *w;
 155
 156         for (w=tdb_list;w;w=w->next) {
 157                 if (strcmp(name, w->name) == 0) {
 158                         return talloc_reference(mem_ctx, w);
 159                 }
 160         }
 161
 162         w = talloc(mem_ctx, struct tdb_wrap);
 163         if (w == NULL) {
 164                 return NULL;
 165         }
 166
 167         w->name = talloc_strdup(w, name);
 168
 169         w->tdb = tdb_open_ex(name, hash_size, tdb_flags,
 170                              open_flags, mode, tdb_wrap_log, NULL);
 171         if (w->tdb == NULL) {
 172                 talloc_free(w);
 173                 return NULL;
 174         }
 175
 176         talloc_set_destructor(w, tdb_wrap_destructor);
 177
 178         DLIST_ADD(tdb_list, w);
 179
 180         return w;
 181 }