lib/util Move source3 tdb_wrap_open() into the common code.

This #if _SAMBA_BUILD == 3 is very unfortunate, as it means that in
the top level build, these options are not available for these
databases.  However, having two different tdb_wrap lists is a worse
fate, so this will do for now.

Andrew Bartlett
(cherry picked from commit 14750139639b3531e57a3ca3f9e481d6e458dc06)
(cherry picked from commit a7f39847ebf29b821aab2570a2f2bd841a28e836)

4 files changed, 246 insertions, 1 deletions

diff --git a/lib/util/tdb_wrap.c b/lib/util/tdb_wrap.c
new file mode 100644
index 00000000000..c9562c69399
--- /dev/null
+++ b/lib/util/tdb_wrap.c
@@ -0,0 +1,194 @@
+/* 
+   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 <tdb.h>
+#include "lib/util/dlinklist.h"
+#include "lib/util/tdb_wrap.h"
+#include <tdb.h>
+
+/*
+ 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);
+	}
+}
+
+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 tdb_wrap_private *result;
+	struct tdb_logging_context log_ctx;
+
+	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;
+	}
+
+	log_ctx.log_fn = tdb_wrap_log;
+
+#if _SAMBA_BUILD_ == 3	
+	/* This #if _SAMBA_BUILD == 3 is very unfortunate, as it means
+	 * that in the top level build, these options are not
+	 * available for these databases.  However, having two
+	 * different tdb_wrap lists is a worse fate, so this will do
+	 * for now */
+
+	if (!lp_use_mmap()) {
+		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 = lp_parm_int(-1, "tdb_hashsize", base, 0);
+	}
+#endif
+
+	result->tdb = tdb_open_ex(name, hash_size, tdb_flags,
+				  open_flags, mode, &log_ctx, 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 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);
+	} 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/util/tdb_wrap.h b/lib/util/tdb_wrap.h
new file mode 100644
index 00000000000..1be2bb059db
--- /dev/null
+++ b/lib/util/tdb_wrap.h
@@ -0,0 +1,42 @@
+/* 
+   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.h>
+
+struct tdb_wrap {
+	struct tdb_context *tdb;
+};
+
+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);
+
+#endif /* _TDB_WRAP_H_ */
diff --git a/lib/util/util_tdb.h b/lib/util/util_tdb.h
index d2f6648462a..c11a347e079 100644
--- a/lib/util/util_tdb.h
+++ b/lib/util/util_tdb.h
@@ -1,7 +1,6 @@
 #ifndef _____LIB_UTIL_UTIL_TDB_H__
 #define _____LIB_UTIL_UTIL_TDB_H__
 
-
 /***************************************************************
  Make a TDB_DATA and keep the const warning in one place
 ****************************************************************/
diff --git a/lib/util/wscript_build b/lib/util/wscript_build
index a5985c6b4e1..b68791f88f2 100755
--- a/lib/util/wscript_build
+++ b/lib/util/wscript_build
@@ -91,3 +91,13 @@ bld.SAMBA_SUBSYSTEM('UTIL_PW',
 	local_include=False,
 	public_deps='talloc'
 	)
+
+
+bld.SAMBA_LIBRARY('tdb-wrap',
+                  source='tdb_wrap.c',
+                  deps='tdb talloc samba-util',
+                  public_headers='tdb_wrap.h',
+                  private_library=True,
+                  local_include=False
+                  )
+