vl: Simplify machine_parse()

Exploit that argument @name is nerver null.  Check is_help_option()
first, because that's what we do elsewhere.  If we (foolishly!)
defined a machine named "help", -machine help would now print help
instead of selecting the machine named "help".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190405064121.23662-5-richardw.yang@linux.intel.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 10 insertions, 12 deletions

diff --git a/vl.c b/vl.c
index 69c530a920..4c794f2bf6 100644
--- a/vl.c
+++ b/vl.c
@@ -2576,19 +2576,10 @@ static gint machine_class_cmp(gconstpointer a, gconstpointer b)
 
 static MachineClass *machine_parse(const char *name, GSList *machines)
 {
-    MachineClass *mc = NULL;
+    MachineClass *mc;
     GSList *el;
 
-    if (name) {
-        mc = find_machine(name, machines);
-    }
-    if (mc) {
-        return mc;
-    }
-    if (name && !is_help_option(name)) {
-        error_report("unsupported machine type");
-        error_printf("Use -machine help to list supported machines\n");
-    } else {
+    if (is_help_option(name)) {
         printf("Supported machines are:\n");
         machines = g_slist_sort(machines, machine_class_cmp);
         for (el = machines; el; el = el->next) {
@@ -2600,9 +2591,16 @@ static MachineClass *machine_parse(const char *name, GSList *machines)
                    mc->is_default ? " (default)" : "",
                    mc->deprecation_reason ? " (deprecated)" : "");
         }
+        exit(0);
     }
 
-    exit(!name || !is_help_option(name));
+    mc = find_machine(name, machines);
+    if (!mc) {
+        error_report("unsupported machine type");
+        error_printf("Use -machine help to list supported machines\n");
+        exit(1);
+    }
+    return mc;
 }
 
 void qemu_add_exit_notifier(Notifier *notify)