service: add support for reboot argument when triggered by StartLimitAction=

When rebooting with systemctl, an optional argument can be passed to the
reboot system call. This makes it possible the specify the argument in a
service file and use it when the service triggers a restart.
This is useful to distinguish between manual reboots and reboots caused by
failing services.

4 files changed, 19 insertions, 0 deletions

diff --git a/src/core/dbus-service.c b/src/core/dbus-service.c
index 0451790d83..45bfecf80d 100644
--- a/src/core/dbus-service.c
+++ b/src/core/dbus-service.c
@@ -50,6 +50,7 @@ const sd_bus_vtable bus_service_vtable[] = {
         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_start_limit_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),
         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),
         SD_BUS_PROPERTY("RemainAfterExit", "b", bus_property_get_bool, offsetof(Service, remain_after_exit), SD_BUS_VTABLE_PROPERTY_CONST),
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index dbb5d13b76..cb98c830b3 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -180,6 +180,7 @@ Service.WatchdogSec,             config_parse_sec,                   0,
 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_start_limit_action,    0,                             offsetof(Service, start_limit_action)
+Service.RebootArgument,          config_parse_string,                0,                             offsetof(Service, reboot_arg)
 Service.Type,                    config_parse_service_type,          0,                             offsetof(Service, type)
 Service.Restart,                 config_parse_service_restart,       0,                             offsetof(Service, restart)
 Service.PermissionsStartOnly,    config_parse_bool,                  0,                             offsetof(Service, permissions_start_only)
diff --git a/src/core/service.c b/src/core/service.c
index ae3695aff2..4ebce6aa95 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -24,6 +24,8 @@
 #include <dirent.h>
 #include <unistd.h>
 #include <sys/reboot.h>
+#include <linux/reboot.h>
+#include <sys/syscall.h>
 
 #include "manager.h"
 #include "unit.h"
@@ -300,6 +302,9 @@ static void service_done(Unit *u) {
         free(s->status_text);
         s->status_text = NULL;
 
+        free(s->reboot_arg);
+        s->reboot_arg = NULL;
+
         s->exec_runtime = exec_runtime_unref(s->exec_runtime);
         exec_command_free_array(s->exec_command, _SERVICE_EXEC_COMMAND_MAX);
         s->control_command = NULL;
@@ -2372,6 +2377,10 @@ static int service_start_limit_test(Service *s) {
         if (ratelimit_test(&s->start_limit))
                 return 0;
 
+        if (s->start_limit_action == SERVICE_START_LIMIT_REBOOT ||
+            s->start_limit_action == SERVICE_START_LIMIT_REBOOT_FORCE)
+                update_reboot_param_file(s->reboot_arg);
+
         switch (s->start_limit_action) {
 
         case SERVICE_START_LIMIT_NONE:
@@ -2407,6 +2416,13 @@ static int service_start_limit_test(Service *s) {
                 log_warning_unit(UNIT(s)->id,
                                  "%s start request repeated too quickly, rebooting immediately.", UNIT(s)->id);
                 sync();
+                if (s->reboot_arg) {
+                        log_info("Rebooting with argument '%s'.", s->reboot_arg);
+                        syscall(SYS_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,
+                                LINUX_REBOOT_CMD_RESTART2, s->reboot_arg);
+                }
+
+                log_info("Rebooting.");
                 reboot(RB_AUTOBOOT);
                 break;
 
diff --git a/src/core/service.h b/src/core/service.h
index 1992926e92..fd05e9be89 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -189,6 +189,7 @@ struct Service {
 
         RateLimit start_limit;
         StartLimitAction start_limit_action;
+        char *reboot_arg;
 
         UnitRef accept_socket;