cmd/app: pass user-specified arguments

An extra argument is added to pad out argv0.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/app/run.go

@@ -12,7 +12,12 @@ import (
 )
 
 // run starts a container via cmd/hakurei and returns after it terminates.
-func run(ctx context.Context, msg message.Msg, config *hst.Config) error {
+func run(
+	ctx context.Context,
+	msg message.Msg,
+	config *hst.Config,
+	args ...string,
+) error {
 	c, cancel := context.WithCancel(ctx)
 	defer cancel()
 
@@ -25,6 +30,7 @@ func run(ctx context.Context, msg message.Msg, config *hst.Config) error {
 		cmd.Args = append(cmd.Args, "-v")
 	}
 	cmd.Args = append(cmd.Args, "run", "3")
+	cmd.Args = append(cmd.Args, args...)
 
 	r, w, err := os.Pipe()
 	if err != nil {