monitor: allow register hmp commands

Allow commands having a NULL cmd pointer, add a function to set the
pointer later.  Use case: allow modules implement hmp commands.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jose R. Ziviani <jziviani@suse.de>
Message-Id: <20210624103836.2382472-31-kraxel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/monitor/misc.c b/monitor/misc.c
index 1539e18..ad476c6 100644
--- a/monitor/misc.c
+++ b/monitor/misc.c
@@ -1974,6 +1974,22 @@
           compare_mon_cmd);
 }
 
+void monitor_register_hmp(const char *name, bool info,
+                          void (*cmd)(Monitor *mon, const QDict *qdict))
+{
+    HMPCommand *table = info ? hmp_info_cmds : hmp_cmds;
+
+    while (table->name != NULL) {
+        if (strcmp(table->name, name) == 0) {
+            g_assert(table->cmd == NULL);
+            table->cmd = cmd;
+            return;
+        }
+        table++;
+    }
+    g_assert_not_reached();
+}
+
 void monitor_init_globals(void)
 {
     monitor_init_globals_core();