core: make the StartLimitXYZ= settings generic and apply to any kind of unit, not just services

This moves the StartLimitBurst=, StartLimitInterval=, StartLimitAction=, RebootArgument= from the [Service] section
into the [Unit] section of unit files, and thus support it in all unit types, not just in services.

This way we can enforce the start limit much earlier, in particular before testing the unit conditions, so that
repeated start-up failure due to failed conditions is also considered for the start limit logic.

For compatibility the four options may also be configured in the [Service] section still, but we only document them in
their new section [Unit].

This also renamed the socket unit failure code "service-failed-permanent" into "service-start-limit-hit" to express
more clearly what it is about, after all it's only triggered through the start limit being hit.

Finally, the code in busname_trigger_notify() and socket_trigger_notify() is altered to become more alike.

Fixes: #2467

13 files changed, 143 insertions, 172 deletions

diff --git a/man/systemd.service.xml b/man/systemd.service.xml
index 4cd36ac70e..2145e33d05 100644
--- a/man/systemd.service.xml
+++ b/man/systemd.service.xml
@@ -874,85 +874,11 @@
       </varlistentry>
 
       <varlistentry>
-        <term><varname>StartLimitInterval=</varname></term>
-        <term><varname>StartLimitBurst=</varname></term>
-
-        <listitem><para>Configure service start rate limiting. By
-        default, services which are started more than 5 times within
-        10 seconds are not permitted to start any more times until the
-        10 second interval ends. With these two options, this rate
-        limiting may be modified. Use
-        <varname>StartLimitInterval=</varname> to configure the
-        checking interval (defaults to
-        <varname>DefaultStartLimitInterval=</varname> in manager
-        configuration file, set to 0 to disable any kind of rate
-        limiting). Use <varname>StartLimitBurst=</varname> to
-        configure how many starts per interval are allowed (defaults
-        to <varname>DefaultStartLimitBurst=</varname> in manager
-        configuration file). These configuration options are
-        particularly useful in conjunction with
-        <varname>Restart=</varname>; however, they apply to all kinds
-        of starts (including manual), not just those triggered by the
-        <varname>Restart=</varname> logic. Note that units which are
-        configured for <varname>Restart=</varname> and which reach the
-        start limit are not attempted to be restarted anymore;
-        however, they may still be restarted manually at a later
-        point, from which point on, the restart logic is again
-        activated. Note that <command>systemctl reset-failed</command>
-        will cause the restart rate counter for a service to be
-        flushed, which is useful if the administrator wants to
-        manually start a service and the start limit interferes with
-        that.</para></listitem>
-      </varlistentry>
-
-      <varlistentry>
-        <term><varname>StartLimitAction=</varname></term>
-
-        <listitem><para>Configure the action to take if the rate limit
-        configured with <varname>StartLimitInterval=</varname> and
-        <varname>StartLimitBurst=</varname> is hit. Takes one of
-        <option>none</option>,
-        <option>reboot</option>,
-        <option>reboot-force</option>,
-        <option>reboot-immediate</option>,
-        <option>poweroff</option>,
-        <option>poweroff-force</option> or
-        <option>poweroff-immediate</option>. If
-        <option>none</option> is set, hitting the rate limit will
-        trigger no action besides that the start will not be
-        permitted. <option>reboot</option> causes a reboot following
-        the normal shutdown procedure (i.e. equivalent to
-        <command>systemctl reboot</command>).
-        <option>reboot-force</option> causes a forced reboot which
-        will terminate all processes forcibly but should cause no
-        dirty file systems on reboot (i.e. equivalent to
-        <command>systemctl reboot -f</command>) and
-        <option>reboot-immediate</option> causes immediate execution
-        of the
-        <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
-        system call, which might result in data loss. Similarly,
-        <option>poweroff</option>, <option>poweroff-force</option>,
-        <option>poweroff-immediate</option> have the effect of
-        powering down the system with similar semantics. Defaults to
-        <option>none</option>.</para></listitem>
-      </varlistentry>
-
-      <varlistentry>
         <term><varname>FailureAction=</varname></term>
-        <listitem><para>Configure the action to take when the service
-        enters a failed state. Takes the same values as
-        <varname>StartLimitAction=</varname> and executes the same
-        actions. Defaults to <option>none</option>. </para></listitem>
-      </varlistentry>
-
-      <varlistentry>
-        <term><varname>RebootArgument=</varname></term>
-        <listitem><para>Configure the optional argument for the
-        <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
-        system call if <varname>StartLimitAction=</varname> or
-        <varname>FailureAction=</varname> is a reboot action. This
-        works just like the optional argument to <command>systemctl
-        reboot</command> command.</para></listitem>
+        <listitem><para>Configure the action to take when the service enters a failed state. Takes the same values as
+        the unit setting <varname>StartLimitAction=</varname> and executes the same actions (see
+        <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>). Defaults to
+        <option>none</option>. </para></listitem>
       </varlistentry>
 
       <varlistentry>
diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index a95c160954..2d3274bbfb 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -760,6 +760,55 @@
       </varlistentry>
 
       <varlistentry>
+        <term><varname>StartLimitInterval=</varname></term>
+        <term><varname>StartLimitBurst=</varname></term>
+
+        <listitem><para>Configure unit start rate limiting. By default, units which are started more than 5 times
+        within 10 seconds are not permitted to start any more times until the 10 second interval ends. With these two
+        options, this rate limiting may be modified. Use <varname>StartLimitInterval=</varname> to configure the
+        checking interval (defaults to <varname>DefaultStartLimitInterval=</varname> in manager configuration file, set
+        to 0 to disable any kind of rate limiting). Use <varname>StartLimitBurst=</varname> to configure how many
+        starts per interval are allowed (defaults to <varname>DefaultStartLimitBurst=</varname> in manager
+        configuration file). These configuration options are particularly useful in conjunction with the service
+        setting <varname>Restart=</varname> (see
+        <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>); however,
+        they apply to all kinds of starts (including manual), not just those triggered by the
+        <varname>Restart=</varname> logic. Note that units which are configured for <varname>Restart=</varname> and
+        which reach the start limit are not attempted to be restarted anymore; however, they may still be restarted
+        manually at a later point, from which point on, the restart logic is again activated. Note that
+        <command>systemctl reset-failed</command> will cause the restart rate counter for a service to be flushed,
+        which is useful if the administrator wants to manually start a unit and the start limit interferes with
+        that.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>StartLimitAction=</varname></term>
+
+        <listitem><para>Configure the action to take if the rate limit configured with
+        <varname>StartLimitInterval=</varname> and <varname>StartLimitBurst=</varname> is hit. Takes one of
+        <option>none</option>, <option>reboot</option>, <option>reboot-force</option>,
+        <option>reboot-immediate</option>, <option>poweroff</option>, <option>poweroff-force</option> or
+        <option>poweroff-immediate</option>. If <option>none</option> is set, hitting the rate limit will trigger no
+        action besides that the start will not be permitted. <option>reboot</option> causes a reboot following the
+        normal shutdown procedure (i.e. equivalent to <command>systemctl reboot</command>).
+        <option>reboot-force</option> causes a forced reboot which will terminate all processes forcibly but should
+        cause no dirty file systems on reboot (i.e. equivalent to <command>systemctl reboot -f</command>) and
+        <option>reboot-immediate</option> causes immediate execution of the
+        <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call, which
+        might result in data loss. Similarly, <option>poweroff</option>, <option>poweroff-force</option>,
+        <option>poweroff-immediate</option> have the effect of powering down the system with similar
+        semantics. Defaults to <option>none</option>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>RebootArgument=</varname></term>
+        <listitem><para>Configure the optional argument for the
+        <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call if
+        <varname>StartLimitAction=</varname> or a service's <varname>FailureAction=</varname> is a reboot action. This
+        works just like the optional argument to <command>systemctl reboot</command> command.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><varname>ConditionArchitecture=</varname></term>
         <term><varname>ConditionVirtualization=</varname></term>
         <term><varname>ConditionHost=</varname></term>
diff --git a/src/core/busname.c b/src/core/busname.c
index 4b0cad8db4..a322252b96 100644
--- a/src/core/busname.c
+++ b/src/core/busname.c
@@ -945,7 +945,6 @@ static void busname_reset_failed(Unit *u) {
 
 static void busname_trigger_notify(Unit *u, Unit *other) {
         BusName *n = BUSNAME(u);
-        Service *s;
 
         assert(n);
         assert(other);
@@ -953,19 +952,22 @@ static void busname_trigger_notify(Unit *u, Unit *other) {
         if (!IN_SET(n->state, BUSNAME_RUNNING, BUSNAME_LISTENING))
                 return;
 
-        if (other->load_state != UNIT_LOADED || other->type != UNIT_SERVICE)
+        if (other->start_limit_hit) {
+                busname_enter_dead(n, BUSNAME_FAILURE_SERVICE_START_LIMIT_HIT);
                 return;
+        }
 
-        s = SERVICE(other);
+        if (other->load_state != UNIT_LOADED || other->type != UNIT_SERVICE)
+                return;
 
-        if (s->state == SERVICE_FAILED && s->result == SERVICE_FAILURE_START_LIMIT)
-                busname_enter_dead(n, BUSNAME_FAILURE_SERVICE_FAILED_PERMANENT);
-        else if (IN_SET(s->state,
-                        SERVICE_DEAD, SERVICE_FAILED,
-                        SERVICE_STOP, SERVICE_STOP_SIGTERM, SERVICE_STOP_SIGKILL,
-                        SERVICE_STOP_POST, SERVICE_FINAL_SIGTERM, SERVICE_FINAL_SIGKILL,
-                        SERVICE_AUTO_RESTART))
+        if (IN_SET(SERVICE(other)->state,
+                   SERVICE_DEAD, SERVICE_FAILED,
+                   SERVICE_FINAL_SIGTERM, SERVICE_FINAL_SIGKILL,
+                   SERVICE_AUTO_RESTART))
                 busname_enter_listening(n);
+
+        if (SERVICE(other)->state == SERVICE_RUNNING)
+                busname_set_state(n, BUSNAME_RUNNING);
 }
 
 static int busname_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
@@ -1006,7 +1008,7 @@ static const char* const busname_result_table[_BUSNAME_RESULT_MAX] = {
         [BUSNAME_FAILURE_EXIT_CODE] = "exit-code",
         [BUSNAME_FAILURE_SIGNAL] = "signal",
         [BUSNAME_FAILURE_CORE_DUMP] = "core-dump",
-        [BUSNAME_FAILURE_SERVICE_FAILED_PERMANENT] = "service-failed-permanent",
+        [BUSNAME_FAILURE_SERVICE_START_LIMIT_HIT] = "service-start-limit-hit",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(busname_result, BusNameResult);
diff --git a/src/core/busname.h b/src/core/busname.h
index 46f7b6f097..bd37083695 100644
--- a/src/core/busname.h
+++ b/src/core/busname.h
@@ -33,7 +33,7 @@ typedef enum BusNameResult {
         BUSNAME_FAILURE_EXIT_CODE,
         BUSNAME_FAILURE_SIGNAL,
         BUSNAME_FAILURE_CORE_DUMP,
-        BUSNAME_FAILURE_SERVICE_FAILED_PERMANENT,
+        BUSNAME_FAILURE_SERVICE_START_LIMIT_HIT,
         _BUSNAME_RESULT_MAX,
         _BUSNAME_RESULT_INVALID = -1
 } BusNameResult;
diff --git a/src/core/dbus-service.c b/src/core/dbus-service.c
index 16f50238a1..f36ce3f9fe 100644
--- a/src/core/dbus-service.c
+++ b/src/core/dbus-service.c
@@ -52,10 +52,11 @@ const sd_bus_vtable bus_service_vtable[] = {
         SD_BUS_PROPERTY("RuntimeMaxUSec", "t", bus_property_get_usec, offsetof(Service, runtime_max_usec), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("WatchdogUSec", "t", bus_property_get_usec, offsetof(Service, watchdog_usec), SD_BUS_VTABLE_PROPERTY_CONST),
         BUS_PROPERTY_DUAL_TIMESTAMP("WatchdogTimestamp", offsetof(Service, watchdog_timestamp), 0),
-        SD_BUS_PROPERTY("StartLimitInterval", "t", bus_property_get_usec, offsetof(Service, start_limit.interval), SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("StartLimitBurst", "u", bus_property_get_unsigned, offsetof(Service, start_limit.burst), SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("StartLimitAction", "s", property_get_failure_action, offsetof(Service, start_limit_action), SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("RebootArgument", "s", NULL, offsetof(Service, reboot_arg), SD_BUS_VTABLE_PROPERTY_CONST),
+        /* The following four are obsolete, and thus marked hidden here. They moved into the Unit interface */
+        SD_BUS_PROPERTY("StartLimitInterval", "t", bus_property_get_usec, offsetof(Unit, start_limit.interval), SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_HIDDEN),
+        SD_BUS_PROPERTY("StartLimitBurst", "u", bus_property_get_unsigned, offsetof(Unit, start_limit.burst), SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_HIDDEN),
+        SD_BUS_PROPERTY("StartLimitAction", "s", property_get_failure_action, offsetof(Unit, start_limit_action), SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_HIDDEN),
+        SD_BUS_PROPERTY("RebootArgument", "s", NULL, offsetof(Unit, reboot_arg), SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_HIDDEN),
         SD_BUS_PROPERTY("FailureAction", "s", property_get_failure_action, offsetof(Service, failure_action), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("PermissionsStartOnly", "b", bus_property_get_bool, offsetof(Service, permissions_start_only), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("RootDirectoryStartOnly", "b", bus_property_get_bool, offsetof(Service, root_directory_start_only), SD_BUS_VTABLE_PROPERTY_CONST),
diff --git a/src/core/dbus-unit.c b/src/core/dbus-unit.c
index d7929e5566..47f8ba5362 100644
--- a/src/core/dbus-unit.c
+++ b/src/core/dbus-unit.c
@@ -704,6 +704,10 @@ const sd_bus_vtable bus_unit_vtable[] = {
         SD_BUS_PROPERTY("LoadError", "(ss)", property_get_load_error, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("Transient", "b", bus_property_get_bool, offsetof(Unit, transient), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("NetClass", "u", NULL, offsetof(Unit, cgroup_netclass_id), 0),
+        SD_BUS_PROPERTY("StartLimitInterval", "t", bus_property_get_usec, offsetof(Unit, start_limit.interval), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("StartLimitBurst", "u", bus_property_get_unsigned, offsetof(Unit, start_limit.burst), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("StartLimitAction", "s", property_get_failure_action, offsetof(Unit, start_limit_action), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("RebootArgument", "s", NULL, offsetof(Unit, reboot_arg), SD_BUS_VTABLE_PROPERTY_CONST),
 
         SD_BUS_METHOD("Start", "s", "o", method_start, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("Stop", "s", "o", method_stop, SD_BUS_VTABLE_UNPRIVILEGED),
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index 2507db1932..c2a47c7b11 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -164,6 +164,10 @@ Unit.IgnoreOnSnapshot,           config_parse_warn_compat,           DISABLED_LE
 Unit.JobTimeoutSec,              config_parse_sec,                   0,                             offsetof(Unit, job_timeout)
 Unit.JobTimeoutAction,           config_parse_failure_action,        0,                             offsetof(Unit, job_timeout_action)
 Unit.JobTimeoutRebootArgument,   config_parse_string,                0,                             offsetof(Unit, job_timeout_reboot_arg)
+Unit.StartLimitInterval,         config_parse_sec,                   0,                             offsetof(Unit, start_limit.interval)
+Unit.StartLimitBurst,            config_parse_unsigned,              0,                             offsetof(Unit, start_limit.burst)
+Unit.StartLimitAction,           config_parse_failure_action,        0,                             offsetof(Unit, start_limit_action)
+Unit.RebootArgument,             config_parse_string,                0,                             offsetof(Unit, reboot_arg)
 Unit.ConditionPathExists,        config_parse_unit_condition_path,   CONDITION_PATH_EXISTS,         offsetof(Unit, conditions)
 Unit.ConditionPathExistsGlob,    config_parse_unit_condition_path,   CONDITION_PATH_EXISTS_GLOB,    offsetof(Unit, conditions)
 Unit.ConditionPathIsDirectory,   config_parse_unit_condition_path,   CONDITION_PATH_IS_DIRECTORY,   offsetof(Unit, conditions)
@@ -216,10 +220,10 @@ Service.TimeoutStartSec,         config_parse_service_timeout,       0,
 Service.TimeoutStopSec,          config_parse_service_timeout,       0,                             offsetof(Service, timeout_stop_usec)
 Service.RuntimeMaxSec,           config_parse_sec,                   0,                             offsetof(Service, runtime_max_usec)
 Service.WatchdogSec,             config_parse_sec,                   0,                             offsetof(Service, watchdog_usec)
-Service.StartLimitInterval,      config_parse_sec,                   0,                             offsetof(Service, start_limit.interval)
-Service.StartLimitBurst,         config_parse_unsigned,              0,                             offsetof(Service, start_limit.burst)
-Service.StartLimitAction,        config_parse_failure_action,        0,                             offsetof(Service, start_limit_action)
-Service.RebootArgument,          config_parse_string,                0,                             offsetof(Service, reboot_arg)
+Service.StartLimitInterval,      config_parse_sec,                   0,                             offsetof(Unit, start_limit.interval)
+Service.StartLimitBurst,         config_parse_unsigned,              0,                             offsetof(Unit, start_limit.burst)
+Service.StartLimitAction,        config_parse_failure_action,        0,                             offsetof(Unit, start_limit_action)
+Service.RebootArgument,          config_parse_string,                0,                             offsetof(Unit, reboot_arg)
 Service.FailureAction,           config_parse_failure_action,        0,                             offsetof(Service, failure_action)
 Service.Type,                    config_parse_service_type,          0,                             offsetof(Service, type)
 Service.Restart,                 config_parse_service_restart,       0,                             offsetof(Service, restart)
diff --git a/src/core/service.c b/src/core/service.c
index 02ce1a566a..3bb3cc8b18 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -119,8 +119,6 @@ static void service_init(Unit *u) {
         s->stdin_fd = s->stdout_fd = s->stderr_fd = -1;
         s->guess_main_pid = true;
 
-        RATELIMIT_INIT(s->start_limit, u->manager->default_start_limit_interval, u->manager->default_start_limit_burst);
-
         s->control_command_id = _SERVICE_EXEC_COMMAND_INVALID;
 }
 
@@ -302,7 +300,6 @@ static void service_done(Unit *u) {
 
         s->pid_file = mfree(s->pid_file);
         s->status_text = mfree(s->status_text);
-        s->reboot_arg = mfree(s->reboot_arg);
 
         s->exec_runtime = exec_runtime_unref(s->exec_runtime);
         exec_command_free_array(s->exec_command, _SERVICE_EXEC_COMMAND_MAX);
@@ -1422,7 +1419,7 @@ static void service_enter_dead(Service *s, ServiceResult f, bool allow_restart)
 
         if (s->result != SERVICE_SUCCESS) {
                 log_unit_warning(UNIT(s), "Failed with result '%s'.", service_result_to_string(s->result));
-                failure_action(UNIT(s)->manager, s->failure_action, s->reboot_arg);
+                failure_action(UNIT(s)->manager, s->failure_action, UNIT(s)->reboot_arg);
         }
 
         if (allow_restart && service_shall_restart(s)) {
@@ -1989,20 +1986,8 @@ fail:
         service_enter_stop(s, SERVICE_FAILURE_RESOURCES);
 }
 
-static int service_start_limit_test(Service *s) {
-        assert(s);
-
-        if (ratelimit_test(&s->start_limit))
-                return 0;
-
-        log_unit_warning(UNIT(s), "Start request repeated too quickly.");
-
-        return failure_action(UNIT(s)->manager, s->start_limit_action, s->reboot_arg);
-}
-
 static int service_start(Unit *u) {
         Service *s = SERVICE(u);
-        int r;
 
         assert(s);
 
@@ -2029,13 +2014,6 @@ static int service_start(Unit *u) {
 
         assert(IN_SET(s->state, SERVICE_DEAD, SERVICE_FAILED));
 
-        /* Make sure we don't enter a busy loop of some kind. */
-        r = service_start_limit_test(s);
-        if (r < 0) {
-                service_enter_dead(s, SERVICE_FAILURE_START_LIMIT, false);
-                return r;
-        }
-
         s->result = SERVICE_SUCCESS;
         s->reload_result = SERVICE_SUCCESS;
         s->main_pid_known = false;
@@ -3248,8 +3226,6 @@ static void service_reset_failed(Unit *u) {
 
         s->result = SERVICE_SUCCESS;
         s->reload_result = SERVICE_SUCCESS;
-
-        RATELIMIT_RESET(s->start_limit);
 }
 
 static int service_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
@@ -3317,7 +3293,6 @@ static const char* const service_result_table[_SERVICE_RESULT_MAX] = {
         [SERVICE_FAILURE_SIGNAL] = "signal",
         [SERVICE_FAILURE_CORE_DUMP] = "core-dump",
         [SERVICE_FAILURE_WATCHDOG] = "watchdog",
-        [SERVICE_FAILURE_START_LIMIT] = "start-limit"
 };
 
 DEFINE_STRING_TABLE_LOOKUP(service_result, ServiceResult);
diff --git a/src/core/service.h b/src/core/service.h
index 24408940d4..55fcec48c7 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -88,7 +88,6 @@ typedef enum ServiceResult {
         SERVICE_FAILURE_SIGNAL,
         SERVICE_FAILURE_CORE_DUMP,
         SERVICE_FAILURE_WATCHDOG,
-        SERVICE_FAILURE_START_LIMIT,
         _SERVICE_RESULT_MAX,
         _SERVICE_RESULT_INVALID = -1
 } ServiceResult;
@@ -178,10 +177,7 @@ struct Service {
         char *status_text;
         int status_errno;
 
-        RateLimit start_limit;
-        FailureAction start_limit_action;
         FailureAction failure_action;
-        char *reboot_arg;
 
         UnitRef accept_socket;
 
diff --git a/src/core/socket.c b/src/core/socket.c
index f0d65577e3..1f24f289e0 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -2702,23 +2702,6 @@ static void socket_reset_failed(Unit *u) {
         s->result = SOCKET_SUCCESS;
 }
 
-static void socket_notify_service_dead(Socket *s, bool failed_permanent) {
-        assert(s);
-
-        /* The service is dead. Dang!
-         *
-         * This is strictly for one-instance-for-all-connections
-         * services. */
-
-        if (s->state == SOCKET_RUNNING) {
-                log_unit_debug(UNIT(s), "Got notified about service death (failed permanently: %s)", yes_no(failed_permanent));
-                if (failed_permanent)
-                        socket_enter_stop_pre(s, SOCKET_FAILURE_SERVICE_FAILED_PERMANENT);
-                else
-                        socket_enter_listening(s);
-        }
-}
-
 void socket_connection_unref(Socket *s) {
         assert(s);
 
@@ -2735,34 +2718,30 @@ void socket_connection_unref(Socket *s) {
 
 static void socket_trigger_notify(Unit *u, Unit *other) {
         Socket *s = SOCKET(u);
-        Service *se;
 
         assert(u);
         assert(other);
 
         /* Don't propagate state changes from the service if we are
            already down or accepting connections */
-        if ((s->state != SOCKET_RUNNING &&
-            s->state != SOCKET_LISTENING) ||
-            s->accept)
+        if (!IN_SET(s->state, SOCKET_RUNNING, SOCKET_LISTENING) || s->accept)
                 return;
 
-        if (other->load_state != UNIT_LOADED ||
-            other->type != UNIT_SERVICE)
+        if (other->start_limit_hit) {
+                socket_enter_stop_pre(s, SOCKET_FAILURE_SERVICE_START_LIMIT_HIT);
                 return;
+        }
 
-        se = SERVICE(other);
-
-        if (se->state == SERVICE_FAILED)
-                socket_notify_service_dead(s, se->result == SERVICE_FAILURE_START_LIMIT);
+        if (other->load_state != UNIT_LOADED || other->type != UNIT_SERVICE)
+                return;
 
-        if (se->state == SERVICE_DEAD ||
-            se->state == SERVICE_FINAL_SIGTERM ||
-            se->state == SERVICE_FINAL_SIGKILL ||
-            se->state == SERVICE_AUTO_RESTART)
-                socket_notify_service_dead(s, false);
+        if (IN_SET(SERVICE(other)->state,
+                   SERVICE_DEAD, SERVICE_FAILED,
+                   SERVICE_FINAL_SIGTERM, SERVICE_FINAL_SIGKILL,
+                   SERVICE_AUTO_RESTART))
+               socket_enter_listening(s);
 
-        if (se->state == SERVICE_RUNNING)
+        if (SERVICE(other)->state == SERVICE_RUNNING)
                 socket_set_state(s, SOCKET_RUNNING);
 }
 
@@ -2818,7 +2797,7 @@ static const char* const socket_result_table[_SOCKET_RESULT_MAX] = {
         [SOCKET_FAILURE_EXIT_CODE] = "exit-code",
         [SOCKET_FAILURE_SIGNAL] = "signal",
         [SOCKET_FAILURE_CORE_DUMP] = "core-dump",
-        [SOCKET_FAILURE_SERVICE_FAILED_PERMANENT] = "service-failed-permanent"
+        [SOCKET_FAILURE_SERVICE_START_LIMIT_HIT] = "service-start-limit-hit"
 };
 
 DEFINE_STRING_TABLE_LOOKUP(socket_result, SocketResult);
diff --git a/src/core/socket.h b/src/core/socket.h
index 08033287a6..ca3f815a47 100644
--- a/src/core/socket.h
+++ b/src/core/socket.h
@@ -54,7 +54,7 @@ typedef enum SocketResult {
         SOCKET_FAILURE_EXIT_CODE,
         SOCKET_FAILURE_SIGNAL,
         SOCKET_FAILURE_CORE_DUMP,
-        SOCKET_FAILURE_SERVICE_FAILED_PERMANENT,
+        SOCKET_FAILURE_SERVICE_START_LIMIT_HIT,
         _SOCKET_RESULT_MAX,
         _SOCKET_RESULT_INVALID = -1
 } SocketResult;
diff --git a/src/core/unit.c b/src/core/unit.c
index be4dac8fea..9df951badb 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -101,6 +101,7 @@ Unit *unit_new(Manager *m, size_t size) {
         u->cgroup_inotify_wd = -1;
         u->job_timeout = USEC_INFINITY;
 
+        RATELIMIT_INIT(u->start_limit, m->default_start_limit_interval, m->default_start_limit_burst);
         RATELIMIT_INIT(u->auto_stop_ratelimit, 10 * USEC_PER_SEC, 16);
 
         return u;
@@ -559,6 +560,8 @@ void unit_free(Unit *u) {
         condition_free_list(u->conditions);
         condition_free_list(u->asserts);
 
+        free(u->reboot_arg);
+
         unit_ref_unset(&u->slice);
 
         while (u->refs)
@@ -1446,23 +1449,36 @@ void unit_status_emit_starting_stopping_reloading(Unit *u, JobType t) {
         unit_status_print_starting_stopping(u, t);
 }
 
+static int unit_start_limit_test(Unit *u) {
+        assert(u);
+
+        if (ratelimit_test(&u->start_limit)) {
+                u->start_limit_hit = false;
+                return 0;
+        }
+
+        log_unit_warning(u, "Start request repeated too quickly.");
+        u->start_limit_hit = true;
+
+        return failure_action(u->manager, u->start_limit_action, u->reboot_arg);
+}
+
 /* Errors:
- *         -EBADR:     This unit type does not support starting.
- *         -EALREADY:  Unit is already started.
- *         -EAGAIN:    An operation is already in progress. Retry later.
- *         -ECANCELED: Too many requests for now.
- *         -EPROTO:    Assert failed
+ *         -EBADR:      This unit type does not support starting.
+ *         -EALREADY:   Unit is already started.
+ *         -EAGAIN:     An operation is already in progress. Retry later.
+ *         -ECANCELED:  Too many requests for now.
+ *         -EPROTO:     Assert failed
+ *         -EINVAL:     Unit not loaded
+ *         -EOPNOTSUPP: Unit type not supported
  */
 int unit_start(Unit *u) {
         UnitActiveState state;
         Unit *following;
+        int r;
 
         assert(u);
 
-        /* Units that aren't loaded cannot be started */
-        if (u->load_state != UNIT_LOADED)
-                return -EINVAL;
-
         /* If this is already started, then this will succeed. Note
          * that this will even succeed if this unit is not startable
          * by the user. This is relied on to detect when we need to
@@ -1471,6 +1487,15 @@ int unit_start(Unit *u) {
         if (UNIT_IS_ACTIVE_OR_RELOADING(state))
                 return -EALREADY;
 
+        /* Make sure we don't enter a busy loop of some kind. */
+        r = unit_start_limit_test(u);
+        if (r < 0)
+                return r;
+
+        /* Units that aren't loaded cannot be started */
+        if (u->load_state != UNIT_LOADED)
+                return -EINVAL;
+
         /* If the conditions failed, don't do anything at all. If we
          * already are activating this call might still be useful to
          * speed up activation in case there is some hold-off time,
@@ -2988,6 +3013,9 @@ void unit_reset_failed(Unit *u) {
 
         if (UNIT_VTABLE(u)->reset_failed)
                 UNIT_VTABLE(u)->reset_failed(u);
+
+        RATELIMIT_RESET(u->start_limit);
+        u->start_limit_hit = false;
 }
 
 Unit *unit_following(Unit *u) {
diff --git a/src/core/unit.h b/src/core/unit.h
index 8712e03133..a87ef74fb3 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -167,6 +167,11 @@ struct Unit {
         /* Error code when we didn't manage to load the unit (negative) */
         int load_error;
 
+        /* Put a ratelimit on unit starting */
+        RateLimit start_limit;
+        FailureAction start_limit_action;
+        char *reboot_arg;
+
         /* Make sure we never enter endless loops with the check unneeded logic, or the BindsTo= logic */
         RateLimit auto_stop_ratelimit;
 
@@ -230,6 +235,8 @@ struct Unit {
         bool cgroup_members_mask_valid:1;
         bool cgroup_subtree_mask_valid:1;
 
+        bool start_limit_hit:1;
+
         /* Did we already invoke unit_coldplug() for this unit? */
         bool coldplugged:1;
 };