s4:lib: merge LDB_WRAP and LDBSAMBA and make LDBSAMBA a library.

This is needed to remove samba specifc symbols from the bundled
ldb, in order to get the ABI right.

metze

Signed-off-by: Andreas Schneider <asn@samba.org>

3 files changed, 331 insertions, 3 deletions

diff --git a/source4/lib/ldb-samba/ldb_wrap.c b/source4/lib/ldb-samba/ldb_wrap.c
new file mode 100644
index 0000000000..d7503829b1
--- /dev/null
+++ b/source4/lib/ldb-samba/ldb_wrap.c
@@ -0,0 +1,284 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   LDB wrap functions
+
+   Copyright (C) Andrew Tridgell 2004-2009
+   
+   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/>.
+*/
+
+/*
+  the stupidity of the unix fcntl locking design forces us to never
+  allow a database file to be opened twice in the same process. These
+  wrappers provide convenient access to a tdb or ldb, taking advantage
+  of talloc destructors to ensure that only a single open is done
+*/
+
+#include "includes.h"
+#include "lib/events/events.h"
+#include "lib/ldb/include/ldb.h"
+#include "lib/ldb/include/ldb_errors.h"
+#include "lib/ldb-samba/ldif_handlers.h"
+#include "ldb_wrap.h"
+#include "dsdb/samdb/samdb.h"
+#include "param/param.h"
+#include "../lib/util/dlinklist.h"
+#include "../tdb/include/tdb.h"
+
+/*
+  this is used to catch debug messages from ldb
+*/
+static void ldb_wrap_debug(void *context, enum ldb_debug_level level, 
+			   const char *fmt, va_list ap)  PRINTF_ATTRIBUTE(3,0);
+
+static void ldb_wrap_debug(void *context, enum ldb_debug_level level, 
+			   const char *fmt, va_list ap)
+{
+	int samba_level = -1;
+	char *s = NULL;
+	switch (level) {
+	case LDB_DEBUG_FATAL:
+		samba_level = 0;
+		break;
+	case LDB_DEBUG_ERROR:
+		samba_level = 1;
+		break;
+	case LDB_DEBUG_WARNING:
+		samba_level = 2;
+		break;
+	case LDB_DEBUG_TRACE:
+		samba_level = 5;
+		break;
+		
+	};
+	vasprintf(&s, fmt, ap);
+	if (!s) return;
+	DEBUG(samba_level, ("ldb: %s\n", s));
+	free(s);
+}
+
+
+/*
+  connecting to a ldb can be a relatively expensive operation because
+  of the schema and partition loads. We keep a list of open ldb
+  contexts here, and try to re-use when possible. 
+
+  This means callers of ldb_wrap_connect() must use talloc_unlink() or
+  the free of a parent to destroy the context
+ */
+static struct ldb_wrap {
+	struct ldb_wrap *next, *prev;
+	struct ldb_wrap_context {
+		/* the context is what we use to tell if two ldb
+		 * connections are exactly equivalent 
+		 */		 
+		const char *url;
+		struct tevent_context *ev;
+		struct loadparm_context *lp_ctx;
+		struct auth_session_info *session_info;
+		struct cli_credentials *credentials;
+		unsigned int flags;
+	} context;
+	struct ldb_context *ldb;
+} *ldb_wrap_list;
+
+/*
+  see if two database opens are equivalent
+ */
+static bool ldb_wrap_same_context(const struct ldb_wrap_context *c1,
+				  const struct ldb_wrap_context *c2)
+{
+	return (c1->ev == c2->ev &&
+		c1->lp_ctx == c2->lp_ctx &&
+		c1->session_info == c2->session_info &&
+		c1->credentials == c2->credentials &&
+		c1->flags == c2->flags &&
+		(c1->url == c2->url || strcmp(c1->url, c2->url) == 0));
+}
+
+/* 
+   free a ldb_wrap structure
+ */
+static int ldb_wrap_destructor(struct ldb_wrap *w)
+{
+	DLIST_REMOVE(ldb_wrap_list, w);
+	return 0;
+}
+
+/*
+  wrapped connection to a ldb database
+  to close just talloc_free() the returned ldb_context
+
+  TODO:  We need an error_string parameter
+ */
+ struct ldb_context *ldb_wrap_connect(TALLOC_CTX *mem_ctx,
+				     struct tevent_context *ev,
+				     struct loadparm_context *lp_ctx,
+				     const char *url,
+				     struct auth_session_info *session_info,
+				     struct cli_credentials *credentials,
+				     unsigned int flags)
+{
+	struct ldb_context *ldb;
+	int ret;
+	char *real_url = NULL;
+	struct ldb_wrap *w;
+	struct ldb_wrap_context c;
+
+	c.url          = url;
+	c.ev           = ev;
+	c.lp_ctx       = lp_ctx;
+	c.session_info = session_info;
+	c.credentials  = credentials;
+	c.flags        = flags;
+
+	/* see if we can re-use an existing ldb */
+	for (w=ldb_wrap_list; w; w=w->next) {
+		if (ldb_wrap_same_context(&c, &w->context)) {
+			return talloc_reference(mem_ctx, w->ldb);
+		}
+	}
+
+	/* we want to use the existing event context if possible. This
+	   relies on the fact that in smbd, everything is a child of
+	   the main event_context */
+	if (ev == NULL) {
+		return NULL;
+	}
+
+	ldb = ldb_init(mem_ctx, ev);
+	if (ldb == NULL) {
+		return NULL;
+	}
+
+	ldb_set_modules_dir(ldb,
+			    talloc_asprintf(ldb,
+					    "%s/ldb",
+					    lp_modulesdir(lp_ctx)));
+
+	if (ldb_set_opaque(ldb, "sessionInfo", session_info)) {
+		talloc_free(ldb);
+		return NULL;
+	}
+
+	if (ldb_set_opaque(ldb, "credentials", credentials)) {
+		talloc_free(ldb);
+		return NULL;
+	}
+
+	if (ldb_set_opaque(ldb, "loadparm", lp_ctx)) {
+		talloc_free(ldb);
+		return NULL;
+	}
+
+	/* This must be done before we load the schema, as these
+	 * handlers for objectSid and objectGUID etc must take
+	 * precedence over the 'binary attribute' declaration in the
+	 * schema */
+	ret = ldb_register_samba_handlers(ldb);
+	if (ret == -1) {
+		talloc_free(ldb);
+		return NULL;
+	}
+
+	if (lp_ctx != NULL && strcmp(lp_sam_url(lp_ctx), url) == 0) {
+		dsdb_set_global_schema(ldb);
+	}
+
+	ldb_set_debug(ldb, ldb_wrap_debug, NULL);
+
+	ldb_set_utf8_fns(ldb, NULL, wrap_casefold);
+
+	real_url = private_path(ldb, lp_ctx, url);
+	if (real_url == NULL) {
+		talloc_free(ldb);
+		return NULL;
+	}
+
+	/* allow admins to force non-sync ldb for all databases */
+	if (lp_parm_bool(lp_ctx, NULL, "ldb", "nosync", false)) {
+		flags |= LDB_FLG_NOSYNC;
+	}
+
+	if (DEBUGLVL(10)) {
+		flags |= LDB_FLG_ENABLE_TRACING;
+	}
+
+	/* we usually want Samba databases to be private. If we later
+	   find we need one public, we will need to add a parameter to
+	   ldb_wrap_connect() */
+	ldb_set_create_perms(ldb, 0600);
+	
+	ret = ldb_connect(ldb, real_url, flags, NULL);
+	if (ret != LDB_SUCCESS) {
+		talloc_free(ldb);
+		return NULL;
+	}
+
+	/* setup for leak detection */
+	ldb_set_opaque(ldb, "wrap_url", real_url);
+	
+	/* add to the list of open ldb contexts */
+	w = talloc(ldb, struct ldb_wrap);
+	if (w == NULL) {
+		talloc_free(ldb);
+		return NULL;
+	}
+
+	w->context = c;
+	w->context.url = talloc_strdup(w, url);
+	if (w->context.url == NULL) {
+		talloc_free(ldb);
+		return NULL;
+	}
+
+	w->ldb = ldb;
+
+	DLIST_ADD(ldb_wrap_list, w);
+
+	/* make the resulting schema global */
+	if (lp_ctx != NULL && strcmp(lp_sam_url(lp_ctx), url) == 0) {
+		struct dsdb_schema *schema = dsdb_get_schema(ldb, NULL);
+		if (schema) {
+			dsdb_make_schema_global(ldb, schema);
+		}
+	}
+
+	DEBUG(3,("ldb_wrap open of %s\n", url));
+
+	talloc_set_destructor(w, ldb_wrap_destructor);
+
+	return ldb;
+}
+
+/*
+  when we fork() we need to make sure that any open ldb contexts have
+  any open transactions cancelled
+ */
+ void ldb_wrap_fork_hook(void)
+{
+	struct ldb_wrap *w;
+
+	for (w=ldb_wrap_list; w; w=w->next) {
+		if (ldb_transaction_cancel_noerr(w->ldb) != LDB_SUCCESS) {
+			smb_panic("Failed to cancel child transactions\n");
+		}
+	}	
+
+	if (tdb_reopen_all(1) == -1) {
+		smb_panic("tdb_reopen_all failed\n");
+	}
+}
+
diff --git a/source4/lib/ldb-samba/ldb_wrap.h b/source4/lib/ldb-samba/ldb_wrap.h
new file mode 100644
index 0000000000..650f97d17d
--- /dev/null
+++ b/source4/lib/ldb-samba/ldb_wrap.h
@@ -0,0 +1,43 @@
+/* 
+   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/>.
+*/
+
+#ifndef _LDB_WRAP_H_
+#define _LDB_WRAP_H_
+
+struct auth_session_info;
+struct ldb_message;
+struct ldb_dn;
+struct cli_credentials;
+struct loadparm_context;
+struct tevent_context;
+
+char *wrap_casefold(void *context, void *mem_ctx, const char *s, size_t n);
+
+struct ldb_context *ldb_wrap_connect(TALLOC_CTX *mem_ctx,
+				     struct tevent_context *ev,
+				     struct loadparm_context *lp_ctx,
+				     const char *url,
+				     struct auth_session_info *session_info,
+				     struct cli_credentials *credentials,
+				     unsigned int flags);
+
+void ldb_wrap_fork_hook(void);
+#endif /* _LDB_WRAP_H_ */
diff --git a/source4/lib/ldb-samba/wscript_build b/source4/lib/ldb-samba/wscript_build
index 15f031ba37..048cea37f4 100644
--- a/source4/lib/ldb-samba/wscript_build
+++ b/source4/lib/ldb-samba/wscript_build
@@ -1,11 +1,12 @@
 #!/usr/bin/env python
 
 
-bld.SAMBA_SUBSYSTEM('LDBSAMBA',
-	source='ldif_handlers.c',
+bld.SAMBA_LIBRARY('LDBSAMBA',
+	source='ldif_handlers.c ldb_wrap.c',
 	autoproto='ldif_handlers_proto.h',
 	public_deps='ldb',
-	deps='LIBSECURITY SAMDB_SCHEMA LIBNDR NDR_DRSBLOBS CREDENTIALS'
+	public_headers='ldb_wrap.h',
+	deps='LIBSECURITY SAMDB_SCHEMA LIBNDR NDR_DRSBLOBS CREDENTIALS UTIL_LDB'
 	)