dbus: add infrastructure for changing multiple properties at once on units and hook some cgroup attributes up to it

This introduces two bus calls to make runtime changes to selected bus
properties, optionally with persistence.

This currently hooks this up only for three cgroup atributes, but this
brings the infrastructure to add more changable attributes.

This allows setting multiple attributes at once, and takes an array
rather than a dictionary of properties, in order to implement simple
resetting of lists using the same approach as when they are sourced from
unit files. This means, that list properties are appended to by this
call, unless they are first reset via assigning the empty list.

11 files changed, 367 insertions, 29 deletions

diff --git a/src/core/dbus-cgroup.c b/src/core/dbus-cgroup.c
index 08ee9c8db4..f7d1dd12ad 100644
--- a/src/core/dbus-cgroup.c
+++ b/src/core/dbus-cgroup.c
@@ -137,3 +137,65 @@ const BusProperty bus_cgroup_context_properties[] = {
         { "DeviceAllow",             bus_cgroup_append_device_allow,      "a(ss)", 0                                           },
         {}
 };
+
+int bus_cgroup_set_property(
+                Unit *u,
+                CGroupContext *c,
+                const char *name,
+                DBusMessageIter *i,
+                UnitSetPropertiesMode mode,
+                DBusError *error) {
+
+        assert(name);
+        assert(u);
+        assert(c);
+        assert(i);
+
+        if (streq(name, "CPUAccounting")) {
+                dbus_bool_t b;
+
+                if (dbus_message_iter_get_arg_type(i) != DBUS_TYPE_BOOLEAN)
+                        return -EINVAL;
+
+                if (mode != UNIT_CHECK) {
+                        dbus_message_iter_get_basic(i, &b);
+
+                        c->cpu_accounting = b;
+                        unit_write_drop_in(u, mode, "cpu-accounting", b ? "CPUAccounting=yes" : "CPUAccounting=no");
+                }
+
+                return 1;
+
+        } else if (streq(name, "BlockIOAccounting")) {
+                dbus_bool_t b;
+
+                if (dbus_message_iter_get_arg_type(i) != DBUS_TYPE_BOOLEAN)
+                        return -EINVAL;
+
+                if (mode != UNIT_CHECK) {
+                        dbus_message_iter_get_basic(i, &b);
+
+                        c->blockio_accounting = b;
+                        unit_write_drop_in(u, mode, "block-io-accounting", b ? "BlockIOAccounting=yes" : "BlockIOAccounting=no");
+                }
+
+                return 1;
+        } else if (streq(name, "MemoryAccounting")) {
+                dbus_bool_t b;
+
+                if (dbus_message_iter_get_arg_type(i) != DBUS_TYPE_BOOLEAN)
+                        return -EINVAL;
+
+                if (mode != UNIT_CHECK) {
+                        dbus_message_iter_get_basic(i, &b);
+
+                        c->blockio_accounting = b;
+                        unit_write_drop_in(u, mode, "memory-accounting", b ? "MemoryAccounting=yes" : "MemoryAccounting=no");
+                }
+
+                return 1;
+        }
+
+
+        return 0;
+}
diff --git a/src/core/dbus-cgroup.h b/src/core/dbus-cgroup.h
index a0a7a7771e..c5908dd976 100644
--- a/src/core/dbus-cgroup.h
+++ b/src/core/dbus-cgroup.h
@@ -42,3 +42,5 @@
         "  <property name=\"DeviceAllow\" type=\"a(ss)\" access=\"read\"/>\n"
 
 extern const BusProperty bus_cgroup_context_properties[];
+
+int bus_cgroup_set_property(Unit *u, CGroupContext *c, const char *name, DBusMessageIter *i, UnitSetPropertiesMode mode, DBusError *error);
diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index c081ff5d16..353cb22867 100644
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -228,12 +228,17 @@
         "   <arg name=\"runtime\" type=\"b\" direction=\"in\"/>\n"      \
         "   <arg name=\"changes\" type=\"a(sss)\" direction=\"out\"/>\n" \
         "  </method>\n"                                                 \
-        "  <method name=\"SetDefaultTarget\">\n"                         \
+        "  <method name=\"SetDefaultTarget\">\n"                        \
         "   <arg name=\"files\" type=\"as\" direction=\"in\"/>\n"       \
         "   <arg name=\"changes\" type=\"a(sss)\" direction=\"out\"/>\n" \
         "  </method>\n"                                                 \
-        "  <method name=\"GetDefaultTarget\">\n"                         \
-        "   <arg name=\"name\" type=\"s\" direction=\"out\"/>\n" \
+        "  <method name=\"GetDefaultTarget\">\n"                        \
+        "   <arg name=\"name\" type=\"s\" direction=\"out\"/>\n"        \
+        "  </method>\n"                                                 \
+        "  <method name=\"SetUnitProperties\">\n"                       \
+        "   <arg name=\"name\" type=\"s\" direction=\"out\"/>\n"        \
+        "   <arg name=\"runtime\" type=\"b\" direction=\"in\"/>\n"      \
+        "   <arg name=\"properties\" type=\"a(sv)\" direction=\"in\"/>\n" \
         "  </method>\n"
 
 #define BUS_MANAGER_INTERFACE_SIGNALS                                   \
@@ -1725,13 +1730,42 @@ static DBusHandlerResult bus_manager_message_handler(DBusConnection *connection,
                         goto oom;
 
                 r = unit_file_get_default(scope, NULL, &default_target);
-
                 if (r < 0)
                         return bus_send_error_reply(connection, message, NULL, r);
 
                 if (!dbus_message_append_args(reply, DBUS_TYPE_STRING, &default_target, DBUS_TYPE_INVALID)) {
                         goto oom;
                 }
+
+        } else if (dbus_message_is_method_call(message, "org.freedesktop.systemd1.Manager", "SetUnitProperties")) {
+                DBusMessageIter iter;
+                dbus_bool_t runtime;
+                const char *name;
+                Unit *u;
+
+                if (!dbus_message_iter_init(message, &iter))
+                        goto oom;
+
+                if (bus_iter_get_basic_and_next(&iter, DBUS_TYPE_STRING, &name, true) < 0 ||
+                    bus_iter_get_basic_and_next(&iter, DBUS_TYPE_BOOLEAN, &runtime, true) < 0)
+                        return bus_send_error_reply(connection, message, NULL, -EINVAL);
+
+                u = manager_get_unit(m, name);
+                if (!u) {
+                        dbus_set_error(&error, BUS_ERROR_NO_SUCH_UNIT, "Unit %s is not loaded.", name);
+                        return bus_send_error_reply(connection, message, &error, -ENOENT);
+                }
+
+                SELINUX_UNIT_ACCESS_CHECK(u, connection, message, "start");
+
+                r = bus_unit_set_properties(u, &iter, runtime ? UNIT_RUNTIME : UNIT_PERSISTENT, &error);
+                if (r < 0)
+                        return bus_send_error_reply(connection, message, &error, r);
+
+                reply = dbus_message_new_method_return(message);
+                if (!reply)
+                        goto oom;
+
         } else {
                 const BusBoundProperties bps[] = {
                         { "org.freedesktop.systemd1.Manager", bus_systemd_properties, systemd_property_string },
diff --git a/src/core/dbus-slice.c b/src/core/dbus-slice.c
index 8243305848..db356adf30 100644
--- a/src/core/dbus-slice.c
+++ b/src/core/dbus-slice.c
@@ -53,10 +53,38 @@ DBusHandlerResult bus_slice_message_handler(Unit *u, DBusConnection *c, DBusMess
         const BusBoundProperties bps[] = {
                 { "org.freedesktop.systemd1.Unit",  bus_unit_properties,           u },
                 { "org.freedesktop.systemd1.Slice", bus_cgroup_context_properties, &s->cgroup_context },
-                { NULL, }
+                {}
         };
 
         SELINUX_UNIT_ACCESS_CHECK(u, c, message, "status");
 
         return bus_default_message_handler(c, message, INTROSPECTION, INTERFACES_LIST, bps);
 }
+
+int bus_slice_set_property(
+                Unit *u,
+                const char *name,
+                DBusMessageIter *i,
+                UnitSetPropertiesMode mode,
+                DBusError *error) {
+
+        Slice *s = SLICE(u);
+        int r;
+
+        assert(name);
+        assert(u);
+        assert(i);
+
+        r = bus_cgroup_set_property(u, &s->cgroup_context, name, i, mode, error);
+        if (r != 0)
+                return r;
+
+        return 0;
+}
+
+int bus_slice_commit_properties(Unit *u) {
+        assert(u);
+
+        unit_realize_cgroup(u);
+        return 0;
+}
diff --git a/src/core/dbus-slice.h b/src/core/dbus-slice.h
index 7e7e29982d..c5ac473763 100644
--- a/src/core/dbus-slice.h
+++ b/src/core/dbus-slice.h
@@ -27,4 +27,7 @@
 
 DBusHandlerResult bus_slice_message_handler(Unit *u, DBusConnection *c, DBusMessage *message);
 
+int bus_slice_set_property(Unit *u, const char *name, DBusMessageIter *i, UnitSetPropertiesMode mode, DBusError *error);
+int bus_slice_commit_properties(Unit *u);
+
 extern const char bus_slice_interface[];
diff --git a/src/core/dbus-unit.c b/src/core/dbus-unit.c
index cbd41342f4..1611da0172 100644
--- a/src/core/dbus-unit.c
+++ b/src/core/dbus-unit.c
@@ -403,6 +403,25 @@ static DBusHandlerResult bus_unit_message_dispatch(Unit *u, DBusConnection *conn
                 reply = dbus_message_new_method_return(message);
                 if (!reply)
                         goto oom;
+        } else if (dbus_message_is_method_call(message, "org.freedesktop.systemd1.Unit", "SetProperties")) {
+                DBusMessageIter iter;
+                dbus_bool_t runtime;
+
+                if (!dbus_message_iter_init(message, &iter))
+                        goto oom;
+
+                if (bus_iter_get_basic_and_next(&iter, DBUS_TYPE_BOOLEAN, &runtime, true) < 0)
+                        return bus_send_error_reply(connection, message, NULL, -EINVAL);
+
+                SELINUX_UNIT_ACCESS_CHECK(u, connection, message, "start");
+
+                r = bus_unit_set_properties(u, &iter, runtime ? UNIT_RUNTIME : UNIT_PERSISTENT, &error);
+                if (r < 0)
+                        return bus_send_error_reply(connection, message, &error, r);
+
+                reply = dbus_message_new_method_return(message);
+                if (!reply)
+                        goto oom;
 
         } else if (UNIT_VTABLE(u)->bus_message_handler)
                 return UNIT_VTABLE(u)->bus_message_handler(u, connection, message);
@@ -745,6 +764,75 @@ oom:
         return DBUS_HANDLER_RESULT_NEED_MEMORY;
 }
 
+int bus_unit_set_properties(Unit *u, DBusMessageIter *iter, UnitSetPropertiesMode mode, DBusError *error) {
+        bool for_real = false;
+        DBusMessageIter sub;
+        unsigned n = 0;
+        int r;
+
+        assert(u);
+        assert(iter);
+
+        /* We iterate through the array twice. First run we just check
+         * if all passed data is valid, second run actually applies
+         * it. This is to implement transaction-like behaviour without
+         * actually providing full transactions. */
+
+        if (dbus_message_iter_get_arg_type(iter) != DBUS_TYPE_ARRAY ||
+            dbus_message_iter_get_element_type(iter) != DBUS_TYPE_STRUCT)
+                return -EINVAL;
+
+        dbus_message_iter_recurse(iter, &sub);
+
+        for (;;) {
+                DBusMessageIter sub2, sub3;
+                const char *name;
+
+                if (dbus_message_iter_get_arg_type(&sub) == DBUS_TYPE_INVALID) {
+
+                        if (for_real)
+                                break;
+
+                        /* Reached EOF. Let's try again, and this time for realz... */
+                        dbus_message_iter_recurse(iter, &sub);
+                        for_real = true;
+                        continue;
+                }
+
+                if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_STRUCT)
+                        return -EINVAL;
+
+                dbus_message_iter_recurse(&sub, &sub2);
+
+                if (bus_iter_get_basic_and_next(&sub2, DBUS_TYPE_STRING, &name, true) < 0 ||
+                    dbus_message_iter_get_arg_type(&sub2) != DBUS_TYPE_VARIANT)
+                        return -EINVAL;
+
+                if (!UNIT_VTABLE(u)->bus_set_property) {
+                        dbus_set_error(error, DBUS_ERROR_PROPERTY_READ_ONLY, "Objects of this type do not support setting properties.");
+                        return -ENOENT;
+                }
+
+                dbus_message_iter_recurse(&sub2, &sub3);
+                r = UNIT_VTABLE(u)->bus_set_property(u, name, &sub3, for_real ? mode : UNIT_CHECK, error);
+                if (r < 0)
+                        return r;
+                if (r == 0) {
+                        dbus_set_error(error, DBUS_ERROR_PROPERTY_READ_ONLY, "Cannot set property %s, or unknown property.", name);
+                        return -ENOENT;
+                }
+
+                dbus_message_iter_next(&sub);
+
+                n += for_real;
+        }
+
+        if (n > 0 && UNIT_VTABLE(u)->bus_commit_properties)
+                UNIT_VTABLE(u)->bus_commit_properties(u);
+
+        return 0;
+}
+
 const BusProperty bus_unit_properties[] = {
         { "Id",                   bus_property_append_string,         "s", offsetof(Unit, id),                                         true },
         { "Names",                bus_unit_append_names,             "as", 0 },
diff --git a/src/core/dbus-unit.h b/src/core/dbus-unit.h
index 1e226ef451..2fd56f25c3 100644
--- a/src/core/dbus-unit.h
+++ b/src/core/dbus-unit.h
@@ -61,6 +61,10 @@
         "   <arg name=\"signal\" type=\"i\" direction=\"in\"/>\n"       \
         "  </method>\n"                                                 \
         "  <method name=\"ResetFailed\"/>\n"                            \
+        "  <method name=\"SetProperties\">\n"                           \
+        "   <arg name=\"runtime\" type=\"b\" direction=\"in\"/>\n"         \
+        "   <arg name=\"properties\" type=\"a(sv)\" direction=\"in\"/>\n" \
+        "  </method>\n"                                                 \
         "  <property name=\"Id\" type=\"s\" access=\"read\"/>\n"        \
         "  <property name=\"Names\" type=\"as\" access=\"read\"/>\n"    \
         "  <property name=\"Following\" type=\"s\" access=\"read\"/>\n" \
@@ -135,19 +139,9 @@ extern const BusProperty bus_unit_properties[];
 void bus_unit_send_change_signal(Unit *u);
 void bus_unit_send_removed_signal(Unit *u);
 
-DBusHandlerResult bus_unit_queue_job(
-                DBusConnection *connection,
-                DBusMessage *message,
-                Unit *u,
-                JobType type,
-                JobMode mode,
-                bool reload_if_possible);
-
-int bus_unit_cgroup_set(Unit *u, DBusMessageIter *iter);
-int bus_unit_cgroup_unset(Unit *u, DBusMessageIter *iter);
-int bus_unit_cgroup_attribute_get(Unit *u, DBusMessageIter *iter, char ***_result);
-int bus_unit_cgroup_attribute_set(Unit *u, DBusMessageIter *iter);
-int bus_unit_cgroup_attribute_unset(Unit *u, DBusMessageIter *iter);
+DBusHandlerResult bus_unit_queue_job(DBusConnection *connection, DBusMessage *message, Unit *u, JobType type, JobMode mode, bool reload_if_possible);
+
+int bus_unit_set_properties(Unit *u, DBusMessageIter *i, UnitSetPropertiesMode mode, DBusError *error);
 
 extern const DBusObjectPathVTable bus_unit_vtable;
 
diff --git a/src/core/slice.c b/src/core/slice.c
index df2d91e473..557f829088 100644
--- a/src/core/slice.c
+++ b/src/core/slice.c
@@ -304,6 +304,8 @@ const UnitVTable slice_vtable = {
 
         .bus_interface = "org.freedesktop.systemd1.Slice",
         .bus_message_handler = bus_slice_message_handler,
+        .bus_set_property = bus_slice_set_property,
+        .bus_commit_properties = bus_slice_commit_properties,
 
         .status_message_formats = {
                 .finished_start_job = {
diff --git a/src/core/unit.c b/src/core/unit.c
index 0dcf85b5e0..be554dac20 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2642,7 +2642,7 @@ CGroupContext *unit_get_cgroup_context(Unit *u) {
         return (CGroupContext*) ((uint8_t*) u + offset);
 }
 
-static int drop_in_file(Unit *u, bool runtime, const char *name, char **_p, char **_q) {
+static int drop_in_file(Unit *u, UnitSetPropertiesMode mode, const char *name, char **_p, char **_q) {
         char *p, *q;
         int r;
 
@@ -2650,8 +2650,9 @@ static int drop_in_file(Unit *u, bool runtime, const char *name, char **_p, char
         assert(name);
         assert(_p);
         assert(_q);
+        assert(mode & (UNIT_PERSISTENT|UNIT_RUNTIME));
 
-        if (u->manager->running_as == SYSTEMD_USER && runtime)
+        if (u->manager->running_as == SYSTEMD_USER && !(mode & UNIT_PERSISTENT))
                 return -ENOTSUP;
 
         if (!filename_is_safe(name))
@@ -2667,10 +2668,10 @@ static int drop_in_file(Unit *u, bool runtime, const char *name, char **_p, char
                         return -ENOENT;
 
                 p = strjoin(c, "/", u->id, ".d", NULL);
-        } else  if (runtime)
-                p = strjoin("/run/systemd/system/", u->id, ".d", NULL);
-        else
+        } else  if (mode & UNIT_PERSISTENT)
                 p = strjoin("/etc/systemd/system/", u->id, ".d", NULL);
+        else
+                p = strjoin("/run/systemd/system/", u->id, ".d", NULL);
         if (!p)
                 return -ENOMEM;
 
@@ -2685,13 +2686,16 @@ static int drop_in_file(Unit *u, bool runtime, const char *name, char **_p, char
         return 0;
 }
 
-int unit_write_drop_in(Unit *u, bool runtime, const char *name, const char *data) {
+int unit_write_drop_in(Unit *u, UnitSetPropertiesMode mode, const char *name, const char *data) {
         _cleanup_free_ char *p = NULL, *q = NULL;
         int r;
 
         assert(u);
 
-        r = drop_in_file(u, runtime, name, &p, &q);
+        if (!(mode & (UNIT_PERSISTENT|UNIT_RUNTIME)))
+                return 0;
+
+        r = drop_in_file(u, mode, name, &p, &q);
         if (r < 0)
                 return r;
 
@@ -2699,13 +2703,16 @@ int unit_write_drop_in(Unit *u, bool runtime, const char *name, const char *data
         return write_string_file_atomic_label(q, data);
 }
 
-int unit_remove_drop_in(Unit *u, bool runtime, const char *name) {
+int unit_remove_drop_in(Unit *u, UnitSetPropertiesMode mode, const char *name) {
         _cleanup_free_ char *p = NULL, *q = NULL;
         int r;
 
         assert(u);
 
-        r = drop_in_file(u, runtime, name, &p, &q);
+        if (!(mode & (UNIT_PERSISTENT|UNIT_RUNTIME)))
+                return 0;
+
+        r = drop_in_file(u, mode, name, &p, &q);
         if (unlink(q) < 0)
                 r = -errno;
         else
diff --git a/src/core/unit.h b/src/core/unit.h
index fbcaabe167..c344719b16 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -260,6 +260,12 @@ struct UnitStatusMessageFormats {
         const char *finished_stop_job[_JOB_RESULT_MAX];
 };
 
+typedef enum UnitSetPropertiesMode {
+        UNIT_CHECK = 0,
+        UNIT_RUNTIME = 1,
+        UNIT_PERSISTENT = 2,
+} UnitSetPropertiesMode;
+
 #include "service.h"
 #include "timer.h"
 #include "socket.h"
@@ -372,6 +378,12 @@ struct UnitVTable {
         /* Called for each message received on the bus */
         DBusHandlerResult (*bus_message_handler)(Unit *u, DBusConnection *c, DBusMessage *message);
 
+        /* Called for each property that is being set */
+        int (*bus_set_property)(Unit *u, const char *name, DBusMessageIter *i, UnitSetPropertiesMode mode, DBusError *error);
+
+        /* Called after at least one property got changed to apply the necessary change */
+        int (*bus_commit_properties)(Unit *u);
+
         /* Return the unit this unit is following */
         Unit *(*following)(Unit *u);
 
@@ -577,8 +589,8 @@ int unit_exec_context_defaults(Unit *u, ExecContext *c);
 ExecContext *unit_get_exec_context(Unit *u) _pure_;
 CGroupContext *unit_get_cgroup_context(Unit *u) _pure_;
 
-int unit_write_drop_in(Unit *u, bool runtime, const char *name, const char *data);
-int unit_remove_drop_in(Unit *u, bool runtime, const char *name);
+int unit_write_drop_in(Unit *u, UnitSetPropertiesMode mode, const char *name, const char *data);
+int unit_remove_drop_in(Unit *u, UnitSetPropertiesMode mode, const char *name);
 
 int unit_kill_context(Unit *u, KillContext *c, bool sigkill, pid_t main_pid, pid_t control_pid, bool main_pid_alien);
 
diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c
index a4f8f2326e..1f81bda7e3 100644
--- a/src/systemctl/systemctl.c
+++ b/src/systemctl/systemctl.c
@@ -3596,6 +3596,109 @@ static int show(DBusConnection *bus, char **args) {
         return ret;
 }
 
+static int append_assignment(DBusMessageIter *iter, const char *assignment) {
+        const char *eq;
+        char *field;
+        DBusMessageIter sub;
+        int r;
+
+        assert(iter);
+        assert(assignment);
+
+        eq = strchr(assignment, '=');
+        if (!eq) {
+                log_error("Not an assignment: %s", assignment);
+                return -EINVAL;
+        }
+
+        field = strndupa(assignment, eq - assignment);
+        eq ++;
+
+        if (!dbus_message_iter_append_basic(iter, DBUS_TYPE_STRING, &field))
+                return log_oom();
+
+        if (streq(field, "CPUAccounting") ||
+            streq(field, "MemoryAccounting") ||
+            streq(field, "BlockIOAccounting")) {
+                dbus_bool_t b;
+
+                r = parse_boolean(eq);
+                if (r < 0) {
+                        log_error("Failed to parse boolean assignment %s.", assignment);
+                        return -EINVAL;
+                }
+
+                b = r;
+                if (!dbus_message_iter_open_container(iter, DBUS_TYPE_VARIANT, "b", &sub) ||
+                    !dbus_message_iter_append_basic(&sub, DBUS_TYPE_BOOLEAN, &b))
+                        return log_oom();
+        } else {
+                log_error("Unknown assignment %s.", assignment);
+                return -EINVAL;
+        }
+
+        if (!dbus_message_iter_close_container(iter, &sub))
+                return log_oom();
+
+        return 0;
+}
+
+static int set_property(DBusConnection *bus, char **args) {
+
+        _cleanup_free_ DBusMessage *m = NULL, *reply = NULL;
+        DBusMessageIter iter, sub;
+        dbus_bool_t runtime;
+        DBusError error;
+        char **i;
+        int r;
+
+        dbus_error_init(&error);
+
+        m = dbus_message_new_method_call(
+                        "org.freedesktop.systemd1",
+                        "/org/freedesktop/systemd1",
+                        "org.freedesktop.systemd1.Manager",
+                        "SetUnitProperties");
+        if (!m)
+                return log_oom();
+
+        dbus_message_iter_init_append(m, &iter);
+
+        runtime = arg_runtime;
+
+        if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &args[1]) ||
+            !dbus_message_iter_append_basic(&iter, DBUS_TYPE_BOOLEAN, &runtime) ||
+            !dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY, "(sv)", &sub))
+                return log_oom();
+
+        STRV_FOREACH(i, args + 2) {
+                DBusMessageIter sub2;
+
+                if (!dbus_message_iter_open_container(&sub, DBUS_TYPE_STRUCT, NULL, &sub2))
+                        return log_oom();
+
+                r = append_assignment(&sub2, *i);
+                if (r < 0)
+                        return r;
+
+                if (!dbus_message_iter_close_container(&sub, &sub2))
+                        return log_oom();
+
+        }
+
+        if (!dbus_message_iter_close_container(&iter, &sub))
+                return log_oom();
+
+        reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error);
+        if (!reply) {
+                log_error("Failed to issue method call: %s", bus_error_message(&error));
+                dbus_error_free(&error);
+                return -EIO;
+        }
+
+        return 0;
+}
+
 static int dump(DBusConnection *bus, char **args) {
         _cleanup_free_ DBusMessage *reply = NULL;
         DBusError error;
@@ -4560,6 +4663,8 @@ static int systemctl_help(void) {
                "  status [NAME...|PID...]         Show runtime status of one or more units\n"
                "  show [NAME...|JOB...]           Show properties of one or more\n"
                "                                  units/jobs or the manager\n"
+               "  set-property [NAME] [ASSIGNMENT...]\n"
+               "                                  Sets one or more properties of a unit\n"
                "  help [NAME...|PID...]           Show manual for one or more units\n"
                "  reset-failed [NAME...]          Reset failed state for all, one, or more\n"
                "                                  units\n"
@@ -5639,6 +5744,7 @@ static int systemctl_main(DBusConnection *bus, int argc, char *argv[], DBusError
                 { "set-default",           EQUAL, 2, enable_unit       },
                 { "get-default",           LESS,  1, get_default       },
                 { "set-log-level",         EQUAL, 2, set_log_level     },
+                { "set-property",          MORE,  3, set_property      },
         };
 
         int left;