commands: handle ctrl-c on active prompt

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

commands/util.go

@@ -0,0 +1,23 @@
+package commands
+
+import (
+	"context"
+	"io"
+
+	"github.com/docker/cli/cli/command"
+)
+
+func prompt(ctx context.Context, ins io.Reader, out io.Writer, msg string) (bool, error) {
+	done := make(chan struct{})
+	var ok bool
+	go func() {
+		ok = command.PromptForConfirmation(ins, out, msg)
+		close(done)
+	}()
+	select {
+	case <-ctx.Done():
+		return false, context.Cause(ctx)
+	case <-done:
+		return ok, nil
+	}
+}