s3-build: Provide a run-time shim to work around duplicate symbols

The become_root() and similar 'smbd' functions that are used widely in
Samba libraries had 'dummy' copies in dummysmbd.c and dummyroot.c.

These have been replaced by a runtime plugin mechanim, which ensures
that standlone binaries still do nothing, while in smbd the correct
function is used.

This avoids having these as duplicate symbols in the smbd binary,
which can cause unpredictable behaviour.

Andrew Bartlett

Signed-off-by: Andrew Tridgell <tridge@samba.org>

1 files changed, 110 insertions, 0 deletions

diff --git a/source3/lib/smbd_shim.c b/source3/lib/smbd_shim.c
new file mode 100644
index 0000000000..72ae366ec3
--- /dev/null
+++ b/source3/lib/smbd_shim.c
@@ -0,0 +1,110 @@
+/*
+   Unix SMB/CIFS implementation.
+   RPC pipe client
+
+   Copyright (C) Gerald (Jerry) Carter          2004.
+   Copyright (C) Andrew Bartlett                2011.
+
+   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/>.
+*/
+
+/* Shim functions required due to the horrible dependency mess
+   in Samba. */
+
+#include "includes.h"
+#include "smbd_shim.h"
+#include "smbd/proto.h"
+
+static struct smbd_shim shim;
+
+void set_smbd_shim(const struct smbd_shim *shim_functions)
+{
+	shim = *shim_functions;
+}
+
+void cancel_pending_lock_requests_by_fid(files_struct *fsp,
+			struct byte_range_lock *br_lck,
+			enum file_close_type close_type)
+{
+	if (shim.cancel_pending_lock_requests_by_fid) {
+
+		shim.cancel_pending_lock_requests_by_fid(fsp, br_lck, close_type);
+	}
+}
+
+void send_stat_cache_delete_message(struct messaging_context *msg_ctx,
+				    const char *name)
+{
+	if (shim.send_stat_cache_delete_message) {
+		shim.send_stat_cache_delete_message(msg_ctx, name);
+	}
+}
+
+NTSTATUS can_delete_directory(struct connection_struct *conn,
+				const char *dirname)
+{
+	if (shim.can_delete_directory) {
+		return shim.can_delete_directory(conn, dirname);
+	}
+	return NT_STATUS_OK;
+}
+
+bool change_to_root_user(void)
+{
+	if (shim.change_to_root_user) {
+		return shim.change_to_root_user();
+	}
+	return false;
+}
+
+/**
+ * The following two functions need to be called from inside the low-level BRL
+ * code for oplocks correctness in smbd.  Since other utility binaries also
+ * link in some of the brl code directly, these dummy functions are necessary
+ * to avoid needing to link in the oplocks code and its dependencies to all of
+ * the utility binaries.
+ */
+void contend_level2_oplocks_begin(files_struct *fsp,
+				  enum level2_contention_type type)
+{
+	if (shim.contend_level2_oplocks_begin) {
+		shim.contend_level2_oplocks_begin(fsp, type);
+	}
+	return;
+}
+
+void contend_level2_oplocks_end(files_struct *fsp,
+				enum level2_contention_type type)
+{
+	if (shim.contend_level2_oplocks_end) {
+		shim.contend_level2_oplocks_end(fsp, type);
+	}
+	return;
+}
+
+void become_root(void)
+{
+	if (shim.become_root) {
+		shim.become_root();
+	}
+        return;
+}
+
+void unbecome_root(void)
+{
+	if (shim.unbecome_root) {
+		shim.unbecome_root();
+	}
+	return;
+}