lvmnotify: add initial dbus notificationdev-dct-notify

This follows the pattern of lvmlockd, which
notifies lvmlockd whenever a VG is updated,
providing the VG name and new seqno.

5 files changed, 120 insertions, 0 deletions

diff --git a/lib/Makefile.in b/lib/Makefile.in
index 3e0e6f87e..d881e797b 100644
--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@@ -115,6 +115,7 @@ SOURCES =\
 	misc/lvm-wrappers.c \
 	misc/lvm-percent.c \
 	mm/memlock.c \
+	notify/lvmnotify.c \
 	properties/prop_common.c \
 	report/properties.c \
 	report/report.c \
@@ -214,6 +215,7 @@ ifeq ($(MAKECMDGOALS),distclean)
 	format_pool \
 	snapshot \
 	mirror \
+	notify \
 	raid \
 	replicator \
 	thin \
diff --git a/lib/metadata/metadata.c b/lib/metadata/metadata.c
index 9bd42c91b..435d2d2bf 100644
--- a/lib/metadata/metadata.c
+++ b/lib/metadata/metadata.c
@@ -602,6 +602,8 @@ int vg_remove_direct(struct volume_group *vg)
 
 	lockd_vg_update(vg);
 
+	notify_vg_update(vg);
+
 	if (!backup_remove(vg->cmd, vg->name))
 		stack;
 
@@ -3195,6 +3197,8 @@ int vg_commit(struct volume_group *vg)
 
 	lockd_vg_update(vg);
 
+	notify_vg_update(vg);
+
 	if (cache_updated) {
 		/* Instruct remote nodes to upgrade cached metadata. */
 		if (!remote_commit_cached_metadata(vg))
diff --git a/lib/notify/lvmnotify.c b/lib/notify/lvmnotify.c
new file mode 100644
index 000000000..e2a73f966
--- /dev/null
+++ b/lib/notify/lvmnotify.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ */
+
+#include "lib.h"
+#include "toolcontext.h"
+#include "metadata.h"
+#include "lvmnotify.h"
+
+#ifdef LVMNOTIFY_SUPPORT
+
+#include <dbus/dbus.h>
+
+#define NOTIFY_DBUS_PATH  "com.lvm"
+#define NOTIFY_DBUS_IFACE "com/lvm"
+
+static DBusConnection *_dbus_con = NULL;
+
+void lvmnotify_init(struct cmd_context *cmd)
+{
+	if (!(_dbus_con = dbus_bus_get_private(DBUS_BUS_SYSTEM, NULL)))
+		log_debug("Failed to connect to dbus");
+}
+
+void lvmnotify_exit(void)
+{
+	if (_dbus_con) {
+		dbus_connection_close(_dbus_con);
+		dbus_connection_unref(_dbus_con);
+	}
+	_dbus_con = NULL;
+}
+
+void notify_vg_update(struct volume_group *vg)
+{
+	DBusMessage *msg = NULL;
+
+	if (_dbus_con && !dbus_connection_read_write(_dbus_con, 1)) {
+		log_debug("Disconnected from dbus");
+		notify_exit();
+	}
+
+	if (!_dbus_con)
+		return;
+
+	if (!(msg = dbus_message_new_signal(NOTIFY_DBUS_PATH,
+					    NOTIFY_DBUS_IFACE,
+					    "vg_update"))) {
+		log_error("Failed to create dbus signal");
+		goto out;
+	}
+
+	if (!dbus_message_append_args(msg,
+				      DBUS_TYPE_STRING, &vg->name,
+				      DBUS_TYPE_INT32, &vg->seqno,
+				      DBUS_TYPE_INVALID)) {
+		log_error("Failed to append args to dbus signal");
+		goto out;
+	}
+
+	dbus_connection_send(_dbus_con, msg, NULL);
+	dbus_connection_flush(_dbus_con);
+
+out:
+	if (msg)
+		dbus_message_unref(msg);
+}
+
+#else
+
+void lvmnotify_init(struct cmd_context *cmd)
+{
+}
+
+void lvmnotify_exit(void)
+{
+}
+
+void notify_vg_update(struct volume_group *vg)
+{
+}
+
+#endif
+
diff --git a/lib/notify/lvmnotify.h b/lib/notify/lvmnotify.h
new file mode 100644
index 000000000..f187358e4
--- /dev/null
+++ b/lib/notify/lvmnotify.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ */
+
+#ifndef _LVMNOTIFY_H
+#define _LVMNOTIFY_H
+
+void lvmnotify_init(struct cmd_context *cmd);
+void lvmnotify_exit(void);
+
+void notify_vg_update(struct volume_group *vg);
+
+#endif
+
diff --git a/tools/lvmcmdline.c b/tools/lvmcmdline.c
index d3bace743..3bf2ca39b 100644
--- a/tools/lvmcmdline.c
+++ b/tools/lvmcmdline.c
@@ -1639,6 +1639,9 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
 		goto_out;
 	}
 
+	if (!_cmd_no_meta_proc(cmd) && !lvmnotify_init(cmd))
+		log_verbose("Unable to initialize notifications.");
+
 	/*
 	 * Other hosts might have changed foreign VGs so enforce a rescan
 	 * before processing any command using them.
@@ -1655,6 +1658,7 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
 	ret = cmd->command->fn(cmd, argc, argv);
 
 	lvmlockd_disconnect();
+	lvmnotify_exit();
 	fin_locking();
 
       out: