tdb_wrap: Move to specific directory.

It's a bit confusing to mix low-level and high-level libraries.  We had
multiple libraries in one directory, and there were have circular
dependencies with other libraries outside that directory (in this case,
samba-hostconfig).

Autobuild-User: Jelmer Vernooij <jelmer@samba.org>
Autobuild-Date: Sat Mar 10 23:13:01 CET 2012 on sn-devel-104

3 files changed, 265 insertions, 0 deletions

diff --git a/lib/tdb_wrap/tdb_wrap.c b/lib/tdb_wrap/tdb_wrap.c
new file mode 100644
index 00000000000..0994b1b79ca
--- /dev/null
+++ b/lib/tdb_wrap/tdb_wrap.c
@@ -0,0 +1,212 @@
+/* 
+   Unix SMB/CIFS implementation.
+   TDB wrap functions
+
+   Copyright (C) Andrew Tridgell 2004
+   Copyright (C) Jelmer Vernooij <jelmer@samba.org> 2007
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "lib/util/dlinklist.h"
+#include "lib/tdb_wrap/tdb_wrap.h"
+#include "lib/param/param.h"
+
+/* FIXME: TDB2 does this internally, so no need to wrap multiple opens! */
+#if BUILD_TDB2
+static void tdb_wrap_log(struct tdb_context *tdb,
+			 enum tdb_log_level level,
+			 enum TDB_ERROR ecode,
+			 const char *message,
+			 void *unused)
+{
+	int dl;
+	const char *name = tdb_name(tdb);
+
+	switch (level) {
+	case TDB_LOG_USE_ERROR:
+	case TDB_LOG_ERROR:
+		dl = 0;
+		break;
+	case TDB_LOG_WARNING:
+		dl = 2;
+		break;
+	default:
+		dl = 0;
+	}
+
+	DEBUG(dl, ("tdb(%s):%s: %s", name ? name : "unnamed",
+		   tdb_errorstr(ecode), message));
+}
+#else
+/*
+ Log tdb messages via DEBUG().
+*/
+static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level, 
+			 const char *format, ...) PRINTF_ATTRIBUTE(3,4);
+
+static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level, 
+			 const char *format, ...)
+{
+	va_list ap;
+	char *ptr = NULL;
+	int debuglevel = 0;
+	int ret;
+
+	switch (level) {
+	case TDB_DEBUG_FATAL:
+		debuglevel = 0;
+		break;
+	case TDB_DEBUG_ERROR:
+		debuglevel = 1;
+		break;
+	case TDB_DEBUG_WARNING:
+		debuglevel = 2;
+		break;
+	case TDB_DEBUG_TRACE:
+		debuglevel = 5;
+		break;
+	default:
+		debuglevel = 0;
+	}		
+
+	va_start(ap, format);
+	ret = vasprintf(&ptr, format, ap);
+	va_end(ap);
+
+	if (ret != -1) {
+		const char *name = tdb_name(tdb);
+		DEBUG(debuglevel, ("tdb(%s): %s", name ? name : "unnamed", ptr));
+		free(ptr);
+	}
+}
+#endif
+
+struct tdb_wrap_private {
+	struct tdb_context *tdb;
+	const char *name;
+	struct tdb_wrap_private *next, *prev;
+};
+
+static struct tdb_wrap_private *tdb_list;
+
+/* destroy the last connection to a tdb */
+static int tdb_wrap_private_destructor(struct tdb_wrap_private *w)
+{
+	tdb_close(w->tdb);
+	DLIST_REMOVE(tdb_list, w);
+	return 0;
+}				 
+
+static struct tdb_wrap_private *tdb_wrap_private_open(TALLOC_CTX *mem_ctx,
+						      const char *name,
+						      int hash_size,
+						      int tdb_flags,
+						      int open_flags,
+						      mode_t mode,
+						      struct loadparm_context *lp_ctx)
+{
+	struct tdb_wrap_private *result;
+
+	result = talloc(mem_ctx, struct tdb_wrap_private);
+	if (result == NULL) {
+		return NULL;
+	}
+	result->name = talloc_strdup(result, name);
+	if (result->name == NULL) {
+		goto fail;
+	}
+
+	if (!lpcfg_use_mmap(lp_ctx)) {
+		tdb_flags |= TDB_NOMMAP;
+	}
+
+	if ((hash_size == 0) && (name != NULL)) {
+		const char *base;
+		base = strrchr_m(name, '/');
+
+		if (base != NULL) {
+			base += 1;
+		} else {
+			base = name;
+		}
+		hash_size = lpcfg_parm_int(lp_ctx, NULL, "tdb_hashsize", base, 0);
+	}
+
+	result->tdb = tdb_open_compat(name, hash_size, tdb_flags,
+				      open_flags, mode, tdb_wrap_log, NULL);
+	if (result->tdb == NULL) {
+		goto fail;
+	}
+	talloc_set_destructor(result, tdb_wrap_private_destructor);
+	DLIST_ADD(tdb_list, result);
+	return result;
+
+fail:
+	TALLOC_FREE(result);
+	return NULL;
+}
+
+/*
+  wrapped connection to a tdb database
+  to close just talloc_free() the tdb_wrap pointer
+ */
+struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
+			       const char *name, int hash_size, int tdb_flags,
+			       int open_flags, mode_t mode,
+			       struct loadparm_context *lp_ctx)
+{
+	struct tdb_wrap *result;
+	struct tdb_wrap_private *w;
+
+	result = talloc(mem_ctx, struct tdb_wrap);
+	if (result == NULL) {
+		return NULL;
+	}
+
+	for (w=tdb_list;w;w=w->next) {
+		if (strcmp(name, w->name) == 0) {
+			break;
+		}
+	}
+
+	if (w == NULL) {
+		w = tdb_wrap_private_open(result, name, hash_size, tdb_flags,
+					  open_flags, mode, lp_ctx);
+	} else {
+		/*
+		 * Correctly use talloc_reference: The tdb will be
+		 * closed when "w" is being freed. The caller never
+		 * sees "w", so an incorrect use of talloc_free(w)
+		 * instead of calling talloc_unlink is not possible.
+		 * To avoid having to refcount ourselves, "w" will
+		 * have multiple parents that hang off all the
+		 * tdb_wrap's being returned from here. Those parents
+		 * can be freed without problem.
+		 */
+		if (talloc_reference(result, w) == NULL) {
+			goto fail;
+		}
+	}
+	if (w == NULL) {
+		goto fail;
+	}
+	result->tdb = w->tdb;
+	return result;
+fail:
+	TALLOC_FREE(result);
+	return NULL;
+}
+
diff --git a/lib/tdb_wrap/tdb_wrap.h b/lib/tdb_wrap/tdb_wrap.h
new file mode 100644
index 00000000000..81e77e76a45
--- /dev/null
+++ b/lib/tdb_wrap/tdb_wrap.h
@@ -0,0 +1,45 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   database wrap headers
+
+   Copyright (C) Andrew Tridgell 2004
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/* IMPORTANT: tdb_wrap should be always preferred over tdb_context for end consumer functions
+   it's because if the code will be running inside smbd, then we must use the linked list
+   of open tdb files, to determine if the tdb we desire is already open
+   as otherwise, when you close the tdb (even on a different file descriptor),
+   ALL LOCKS are lost (due to a real screwup in the POSIX specification that nobody has been able to get fixed)
+*/
+
+#ifndef _TDB_WRAP_H_
+#define _TDB_WRAP_H_
+
+#include "tdb_compat.h"
+
+struct tdb_wrap {
+	struct tdb_context *tdb;
+};
+
+struct loadparm_context;
+
+struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
+			       const char *name, int hash_size, int tdb_flags,
+			       int open_flags, mode_t mode,
+			       struct loadparm_context *lp_ctx);
+
+#endif /* _TDB_WRAP_H_ */
diff --git a/lib/tdb_wrap/wscript_build b/lib/tdb_wrap/wscript_build
new file mode 100644
index 00000000000..0811bc5a2db
--- /dev/null
+++ b/lib/tdb_wrap/wscript_build
@@ -0,0 +1,8 @@
+#!/usr/bin/python
+
+bld.SAMBA_LIBRARY('tdb-wrap',
+                  source='tdb_wrap.c',
+                  deps='tdb_compat talloc samba-util samba-hostconfig',
+                  private_library=True,
+                  local_include=False
+                 )