dbus: add notification from commands

When a command modifies a PV or VG, or changes the
activation state of an LV, it will send a dbus
notification when the command is finished.  This
can be enabled/disabled with a config setting.

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.146 - 
 =================================
+  Add dbus notification from commands after a PV/VG/LV changes state.
 
 Version 2.02.145 - 4th March 2016
 =================================

configure.in

@@ -1268,6 +1268,28 @@ fi
 AC_DEFINE_UNQUOTED(DEFAULT_USE_LVMPOLLD, [$DEFAULT_USE_LVMPOLLD],
 		   [Use lvmpolld by default.])
 
+################################################################################
+dnl -- Build notifydbus
+AC_MSG_CHECKING(whether to build notifydbus)
+AC_ARG_ENABLE(notify-dbus,
+	      AC_HELP_STRING([--enable-notify-dbus],
+			     [enable LVM notification using dbus]),
+	      NOTIFYDBUS=$enableval)
+AC_MSG_RESULT($NOTIFYDBUS)
+
+BUILD_NOTIFYDBUS=$NOTIFYDBUS
+
+if test "$BUILD_NOTIFYDBUS" = yes; then
+	AC_DEFINE([NOTIFYDBUS_SUPPORT], 1, [Define to 1 to include code that uses dbus notification.])
+	LIBS="-lsystemd $LIBS"
+fi
+
+################################################################################
+dnl -- Look for dbus libraries
+if test "$BUILD_NOTIFYDBUS" = yes; then
+	PKG_CHECK_MODULES(NOTIFY_DBUS, systemd >= 221, [HAVE_NOTIFY_DBUS=yes], $bailout)
+fi
+
 ################################################################################
 
 dnl -- Enable blkid wiping functionality
@@ -1965,6 +1987,7 @@ AC_SUBST(BUILD_LVMPOLLD)
 AC_SUBST(BUILD_LVMLOCKD)
 AC_SUBST(BUILD_LOCKDSANLOCK)
 AC_SUBST(BUILD_LOCKDDLM)
+AC_SUBST(BUILD_NOTIFYDBUS)
 AC_SUBST(CACHE)
 AC_SUBST(CFLAGS)
 AC_SUBST(CFLOW_CMD)

include/.symlinks.in

@@ -58,6 +58,7 @@
 @top_srcdir@/lib/misc/util.h
 @top_srcdir@/lib/mm/memlock.h
 @top_srcdir@/lib/mm/xlate.h
+@top_srcdir@/lib/notify/lvmnotify.h
 @top_srcdir@/lib/properties/prop_common.h
 @top_srcdir@/lib/report/properties.h
 @top_srcdir@/lib/report/report.h

lib/Makefile.in

@@ -116,6 +116,7 @@ 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 \
@@ -215,6 +216,7 @@ ifeq ($(MAKECMDGOALS),distclean)
 	format_pool \
 	snapshot \
 	mirror \
+	notify \
 	raid \
 	replicator \
 	thin \

lib/commands/toolcontext.c

@@ -278,6 +278,8 @@ static int _parse_debug_classes(struct cmd_context *cmd)
 			debug_classes |= LOG_CLASS_LOCKING;
 		else if (!strcasecmp(cv->v.str, "lvmpolld"))
 			debug_classes |= LOG_CLASS_LVMPOLLD;
+		else if (!strcasecmp(cv->v.str, "dbus"))
+			debug_classes |= LOG_CLASS_DBUS;
 		else
 			log_verbose("Unrecognised value for log/debug_classes: %s", cv->v.str);
 	}

lib/commands/toolcontext.h

@@ -141,6 +141,9 @@ struct cmd_context {
 	unsigned lockd_vg_rescan:1;
 	unsigned lockd_vg_default_sh:1;
 	unsigned lockd_vg_enforce_sh:1;
+	unsigned vg_notify:1;
+	unsigned lv_notify:1;
+	unsigned pv_notify:1;
 
 	/*
 	 * Filtering.

lib/config/config_settings.h

@@ -581,7 +581,7 @@ cfg(log_activation_CFG, "activation", log_CFG_SECTION, 0, CFG_TYPE_BOOL, 0, vsn(
 
 cfg(log_activate_file_CFG, "activate_file", log_CFG_SECTION, CFG_DEFAULT_UNDEFINED | CFG_UNSUPPORTED, CFG_TYPE_STRING, NULL, vsn(1, 0, 0), NULL, 0, NULL, NULL)
 
-cfg_array(log_debug_classes_CFG, "debug_classes", log_CFG_SECTION, CFG_ALLOW_EMPTY, CFG_TYPE_STRING, "#Smemory#Sdevices#Sactivation#Sallocation#Slvmetad#Smetadata#Scache#Slocking#Slvmpolld", vsn(2, 2, 99), NULL, 0, NULL,
+cfg_array(log_debug_classes_CFG, "debug_classes", log_CFG_SECTION, CFG_ALLOW_EMPTY, CFG_TYPE_STRING, "#Smemory#Sdevices#Sactivation#Sallocation#Slvmetad#Smetadata#Scache#Slocking#Slvmpolld#Sdbus", vsn(2, 2, 99), NULL, 0, NULL,
 	"Select log messages by class.\n"
 	"Some debugging messages are assigned to a class and only appear in\n"
 	"debug output if the class is listed here. Classes currently\n"
@@ -995,6 +995,11 @@ cfg(global_use_lvmpolld_CFG, "use_lvmpolld", global_CFG_SECTION, 0, CFG_TYPE_BOO
 	"and to use its own control group. When this option is disabled, LVM\n"
 	"commands will supervise long running operations by forking themselves.\n")
 
+cfg(global_notify_dbus_CFG, "notify_dbus", global_CFG_SECTION, 0, CFG_TYPE_BOOL, DEFAULT_NOTIFY_DBUS, vsn(2, 2, 145), NULL, 0, NULL,
+	"Enable D-Bus notification from LVM commands.\n"
+	"When enabled, an LVM command that changes PVs, changes VG metadata,\n"
+	"or changes the activation state of an LV will send a notification.\n")
+
 cfg(activation_udev_sync_CFG, "udev_sync", activation_CFG_SECTION, 0, CFG_TYPE_BOOL, DEFAULT_UDEV_SYNC, vsn(2, 2, 51), NULL, 0, NULL,
 	"Use udev notifications to synchronize udev and LVM.\n"
 	"The --nodevsync option overrides this setting.\n"

lib/config/defaults.h

@@ -138,6 +138,7 @@
 #define DEFAULT_READ_AHEAD "auto"
 #define DEFAULT_UDEV_RULES 1
 #define DEFAULT_UDEV_SYNC 1
+#define DEFAULT_NOTIFY_DBUS 1
 #define DEFAULT_VERIFY_UDEV_OPERATIONS 0
 #define DEFAULT_RETRY_DEACTIVATION 1
 #define DEFAULT_ACTIVATION_CHECKS 0

lib/log/log.h

@@ -66,6 +66,7 @@
 #define LOG_CLASS_CACHE		0x0040	/* "cache" */
 #define LOG_CLASS_LOCKING	0x0080	/* "locking" */
 #define LOG_CLASS_LVMPOLLD	0x0100	/* "lvmpolld" */
+#define LOG_CLASS_DBUS		0x0200	/* "dbus" */
 
 #define log_debug(x...) LOG_LINE(_LOG_DEBUG, x)
 #define log_debug_mem(x...) LOG_LINE_WITH_CLASS(_LOG_DEBUG, LOG_CLASS_MEM, x)
@@ -77,6 +78,7 @@
 #define log_debug_cache(x...) LOG_LINE_WITH_CLASS(_LOG_DEBUG, LOG_CLASS_CACHE, x)
 #define log_debug_locking(x...) LOG_LINE_WITH_CLASS(_LOG_DEBUG, LOG_CLASS_LOCKING, x)
 #define log_debug_lvmpolld(x...) LOG_LINE_WITH_CLASS(_LOG_DEBUG, LOG_CLASS_LVMPOLLD, x)
+#define log_debug_dbus(x...) LOG_LINE_WITH_CLASS(_LOG_DEBUG, LOG_CLASS_DBUS, x)
 
 #define log_info(x...) LOG_LINE(_LOG_INFO, x)
 #define log_notice(x...) LOG_LINE(_LOG_NOTICE, x)

lib/metadata/metadata.c

@@ -33,6 +33,7 @@
 #include "defaults.h"
 #include "lvmlockd.h"
 #include "time.h"
+#include "lvmnotify.h"
 
 #include <math.h>
 #include <sys/param.h>
@@ -604,6 +605,8 @@ int vg_remove_direct(struct volume_group *vg)
 
 	lockd_vg_update(vg);
 
+	set_vg_notify(vg->cmd);
+
 	if (!backup_remove(vg->cmd, vg->name))
 		stack;
 
@@ -3591,6 +3594,8 @@ int vg_commit(struct volume_group *vg)
 
 	cache_updated = _vg_commit_mdas(vg);
 
+	set_vg_notify(vg->cmd);
+
 	if (cache_updated) {
 		/* Instruct remote nodes to upgrade cached metadata. */
 		if (!remote_commit_cached_metadata(vg))

lib/notify/lvmnotify.c

@@ -0,0 +1,109 @@
+/*
+ * 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"
+
+#define LVM_DBUS_DESTINATION "com.redhat.lvmdbus1"
+#define LVM_DBUS_PATH        "/com/redhat/lvmdbus1/Manager"
+#define LVM_DBUS_INTERFACE   "com.redhat.lvmdbus1.Manager"
+
+#ifdef NOTIFYDBUS_SUPPORT
+#include <systemd/sd-bus.h>
+
+void lvmnotify_send(struct cmd_context *cmd)
+{
+	sd_bus *bus = NULL;
+	sd_bus_message *m = NULL;
+	sd_bus_error error = SD_BUS_ERROR_NULL;
+	const char *cmd_name;
+	int ret;
+	int result = 0;
+
+	if (!cmd->vg_notify && !cmd->lv_notify && !cmd->pv_notify)
+		return;
+
+	cmd->vg_notify = 0;
+	cmd->lv_notify = 0;
+	cmd->pv_notify = 0;
+
+	cmd_name = get_cmd_name();
+
+	ret = sd_bus_open_system(&bus);
+	if (ret < 0) {
+		log_debug_dbus("Failed to connect to dbus: %d", ret);
+		return;
+	}
+
+	log_debug_dbus("Nofify dbus at %s.", LVM_DBUS_DESTINATION);
+
+	ret = sd_bus_call_method(bus,
+				 LVM_DBUS_DESTINATION,
+				 LVM_DBUS_PATH,
+				 LVM_DBUS_INTERFACE,
+				 "ExternalEvent",
+				 &error,
+				 &m,
+				 "s",
+				 cmd_name);
+
+	if (ret < 0) {
+		log_warn("WARNING: D-Bus notification failed: %s", error.message);
+		goto out;
+	}
+
+	ret = sd_bus_message_read(m, "i", &result);
+	if (ret < 0)
+		log_debug_dbus("Failed to parse dbus response message: %d", ret);
+	if (result)
+		log_debug_dbus("Bad return value from dbus service: %d", result);
+out:
+	sd_bus_error_free(&error);
+	sd_bus_message_unref(m);
+	sd_bus_unref(bus);
+}
+
+void set_vg_notify(struct cmd_context *cmd)
+{
+	cmd->vg_notify = 1;
+}
+
+void set_lv_notify(struct cmd_context *cmd)
+{
+	cmd->lv_notify = 1;
+}
+
+void set_pv_notify(struct cmd_context *cmd)
+{
+	cmd->pv_notify = 1;
+}
+
+#else
+
+void lvmnotify_send(struct cmd_context *cmd)
+{
+}
+
+void set_vg_notify(struct cmd_context *cmd)
+{
+}
+
+void set_lv_notify(struct cmd_context *cmd)
+{
+}
+
+void set_pv_notify(struct cmd_context *cmd)
+{
+}
+
+#endif
+

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_send(struct cmd_context *cmd);
+void set_vg_notify(struct cmd_context *cmd);
+void set_lv_notify(struct cmd_context *cmd);
+void set_pv_notify(struct cmd_context *cmd);
+
+#endif
+

tools/lvmcmdline.c

@@ -1660,6 +1660,9 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
 	lvmlockd_disconnect();
 	fin_locking();
 
+	if (!_cmd_no_meta_proc(cmd) && find_config_tree_bool(cmd, global_notify_dbus_CFG, NULL))
+		lvmnotify_send(cmd);
+
       out:
 	if (test_mode()) {
 		log_verbose("Test mode: Wiping internal cache");

tools/pvchange.c

@@ -228,6 +228,8 @@ int pvchange(struct cmd_context *cmd, int argc, char **argv)
 		}
 	}
 
+	set_pv_notify(cmd);
+
 	ret = process_each_pv(cmd, argc, argv, NULL, 0, READ_FOR_UPDATE, handle, _pvchange_single);
 
 	if (!argc)

tools/pvresize.c

@@ -79,6 +79,8 @@ int pvresize(struct cmd_context *cmd, int argc, char **argv)
 	params.done = 0;
 	params.total = 0;
 
+	set_pv_notify(cmd);
+
 	if (!(handle = init_processing_handle(cmd))) {
 		log_error("Failed to initialize processing handle.");
 		ret = ECMD_FAILED;

tools/toollib.c

@@ -1069,6 +1069,8 @@ int lv_change_activate(struct cmd_context *cmd, struct logical_volume *lv,
 	if (!lv_active_change(cmd, lv, activate, 0))
 		return_0;
 
+	set_lv_notify(lv->vg->cmd);
+
 	return r;
 }
 
@@ -4179,6 +4181,8 @@ int pvcreate_each_device(struct cmd_context *cmd,
 	int found;
 	int i;
 
+	set_pv_notify(cmd);
+
 	dm_list_init(&arg_sort);
 
 	handle->custom_handle = pp;

tools/tools.h

@@ -42,6 +42,7 @@
 #include "str_list.h"
 #include "toolcontext.h"
 #include "toollib.h"
+#include "lvmnotify.h"
 
 #include <ctype.h>
 #include <sys/types.h>