target: introduce target_get_runlevel() for distilling SysV compatible runlevel information from a target

2 files changed, 33 insertions, 1 deletions

diff --git a/target.c b/target.c
index c80c09d546..f34ba0c36d 100644
--- a/target.c
+++ b/target.c
@@ -89,6 +89,35 @@ static UnitActiveState target_active_state(Unit *u) {
         return state_translation_table[TARGET(u)->state];
 }
 
+int target_get_runlevel(Target *t) {
+
+        static const struct {
+                const char *special;
+                const int runlevel;
+        } table[] = {
+                { SPECIAL_RUNLEVEL5_TARGET, '5' },
+                { SPECIAL_RUNLEVEL4_TARGET, '4' },
+                { SPECIAL_RUNLEVEL3_TARGET, '3' },
+                { SPECIAL_RUNLEVEL2_TARGET, '2' },
+                { SPECIAL_RUNLEVEL1_TARGET, '1' },
+                { SPECIAL_RUNLEVEL0_TARGET, '0' },
+                { SPECIAL_RUNLEVEL6_TARGET, '6' },
+        };
+
+        unsigned i;
+
+        assert(t);
+
+        /* Tries to determine if this is a SysV runlevel and returns
+         * it if that is so. */
+
+        for (i = 0; i < ELEMENTSOF(table); i++)
+                if (unit_has_name(UNIT(t), table[i].special))
+                        return table[i].runlevel;
+
+        return 0;
+}
+
 const UnitVTable target_vtable = {
         .suffix = ".target",
 
diff --git a/target.h b/target.h
index 6ee9f22013..4b04635f94 100644
--- a/target.h
+++ b/target.h
@@ -29,7 +29,8 @@ typedef struct Target Target;
 typedef enum TargetState {
         TARGET_DEAD,
         TARGET_ACTIVE,
-        _TARGET_STATE_MAX
+        _TARGET_STATE_MAX,
+        _TARGET_STATE_INVALID = -1
 } TargetState;
 
 struct Target {
@@ -40,4 +41,6 @@ struct Target {
 
 extern const UnitVTable target_vtable;
 
+int target_get_runlevel(Target *t);
+
 #endif