osbase/bringup: add bringup

Introduce a library which handles the bringup of a running environment
for supervisor runnables.

Change-Id: I03c049d1bac7afdc71dfa24247923070982f07cd
Reviewed-on: https://review.monogon.dev/c/monogon/+/2930
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/osbase/bringup/test/run_test.go b/osbase/bringup/test/run_test.go
new file mode 100644
index 0000000..3252c54
--- /dev/null
+++ b/osbase/bringup/test/run_test.go
@@ -0,0 +1,90 @@
+package test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/bazelbuild/rules_go/go/runfiles"
+
+	"source.monogon.dev/osbase/cmd"
+)
+
+var (
+	// These are filled by bazel at linking time with the canonical path of
+	// their corresponding file. Inside the init function we resolve it
+	// with the rules_go runfiles package to the real path.
+	xOvmfCodePath      string
+	xOvmfVarsPath      string
+	xQemuPath          string
+	xSucceedKernelPath string
+	xFailedKernelPath  string
+)
+
+func init() {
+	var err error
+	for _, path := range []*string{
+		&xOvmfCodePath, &xOvmfVarsPath, &xQemuPath,
+		&xSucceedKernelPath, &xFailedKernelPath,
+	} {
+		*path, err = runfiles.Rlocation(*path)
+		if err != nil {
+			panic(err)
+		}
+	}
+}
+
+// runQemu starts a new QEMU process, expecting the given output to appear
+// in any line printed. It returns true, if the expected string was found,
+// and false otherwise.
+//
+// QEMU is killed shortly after the string is found, or when the context is
+// cancelled.
+func runQemu(ctx context.Context, args []string, expectedOutput string) (bool, error) {
+	defaultArgs := []string{
+		"-machine", "q35", "-accel", "kvm", "-nographic", "-nodefaults",
+		"-m", "512",
+		"-smp", "2",
+		"-cpu", "host",
+		"-drive", "if=pflash,format=raw,snapshot=on,file=" + xOvmfCodePath,
+		"-drive", "if=pflash,format=raw,readonly=on,file=" + xOvmfVarsPath,
+		"-serial", "stdio",
+		"-no-reboot",
+	}
+	qemuArgs := append(defaultArgs, args...)
+	pf := cmd.TerminateIfFound(expectedOutput, nil)
+	return cmd.RunCommand(ctx, xQemuPath, qemuArgs, pf)
+}
+
+func TestBringupSuccess(t *testing.T) {
+	ctx, ctxC := context.WithTimeout(context.Background(), time.Second*30)
+	defer ctxC()
+
+	extraArgs := append([]string(nil), "-kernel", xSucceedKernelPath)
+
+	// Run QEMU. Expect the installer to succeed with a predefined error string.
+	expectedOutput := "_BRINGUP_LAUNCH_SUCCESS_"
+	result, err := runQemu(ctx, extraArgs, expectedOutput)
+	if err != nil {
+		t.Error(err.Error())
+	}
+	if !result {
+		t.Errorf("QEMU didn't produce the expected output %q", expectedOutput)
+	}
+}
+func TestBringupFailed(t *testing.T) {
+	ctx, ctxC := context.WithTimeout(context.Background(), time.Second*30)
+	defer ctxC()
+
+	extraArgs := append([]string(nil), "-kernel", xFailedKernelPath)
+
+	// Run QEMU. Expect the installer to fail with a predefined error string.
+	expectedOutput := "root runnable paniced"
+	result, err := runQemu(ctx, extraArgs, expectedOutput)
+	if err != nil {
+		t.Error(err.Error())
+	}
+	if !result {
+		t.Errorf("QEMU didn't produce the expected output %q", expectedOutput)
+	}
+}