runstate: Add runstate store

This allows us to store the current state to send it through migration.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

include/sysemu/sysemu.h

@@ -28,6 +28,7 @@ bool runstate_check(RunState state);
 void runstate_set(RunState new_state);
 int runstate_is_running(void);
 bool runstate_needs_reset(void);
+bool runstate_store(char *str, size_t size);
 typedef struct vm_change_state_entry VMChangeStateEntry;
 typedef void VMChangeStateHandler(void *opaque, int running, RunState state);
 

vl.c

@@ -634,6 +634,18 @@ bool runstate_check(RunState state)
     return current_run_state == state;
 }
 
+bool runstate_store(char *str, size_t size)
+{
+    const char *state = RunState_lookup[current_run_state];
+    size_t len = strlen(state) + 1;
+
+    if (len > size) {
+        return false;
+    }
+    memcpy(str, state, len);
+    return true;
+}
+
 static void runstate_init(void)
 {
     const RunStateTransition *p;