Init

cmd/agent/main.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+)
+
+func main() {
+	cfg := flag.String("config", defaultConfigPath(), "agent config path")
+	action := flag.String("service", "", "service action: install|uninstall|start|stop|run")
+	flag.Parse()
+	if err := platformMain(*action, *cfg); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}

cmd/agent/platform_other.go

@@ -0,0 +1,31 @@
+//go:build !windows
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"os/signal"
+	"syscall"
+
+	"github.com/example/sessionguard/internal/agent"
+	"github.com/example/sessionguard/internal/config"
+)
+
+func defaultConfigPath() string { return "./agent.json" }
+func platformMain(action, path string) error {
+	if action != "" && action != "run" {
+		return fmt.Errorf("Windows service actions are only available on Windows")
+	}
+	cfg, err := config.LoadAgent(path)
+	if err != nil {
+		return err
+	}
+	app, err := agent.New(cfg)
+	if err != nil {
+		return err
+	}
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+	return app.Run(ctx)
+}

cmd/agent/platform_windows.go

@@ -0,0 +1,172 @@
+//go:build windows
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"github.com/example/sessionguard/internal/agent"
+	"github.com/example/sessionguard/internal/config"
+	"golang.org/x/sys/windows/svc"
+	"golang.org/x/sys/windows/svc/mgr"
+)
+
+const serviceName = "SessionGuardAgent"
+
+func defaultConfigPath() string { return `C:\ProgramData\SessionGuard\agent.json` }
+
+func platformMain(action, path string) error {
+	switch action {
+	case "install":
+		return installService(path)
+	case "uninstall":
+		return uninstallService()
+	case "start":
+		return startService()
+	case "stop":
+		return stopService()
+	case "run":
+		return runAsService(path)
+	case "":
+		isSvc, err := svc.IsWindowsService()
+		if err == nil && isSvc {
+			return runAsService(path)
+		}
+		return runConsole(path)
+	default:
+		return fmt.Errorf("unknown service action %q", action)
+	}
+}
+
+func setupLog(dataDir string) {
+	_ = os.MkdirAll(dataDir, 0o700)
+	f, err := os.OpenFile(filepath.Join(dataDir, "agent.log"), os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o600)
+	if err == nil {
+		log.SetOutput(f)
+	}
+	log.SetFlags(log.LstdFlags | log.Lmicroseconds | log.LUTC)
+}
+func loadApp(path string) (*agent.App, error) {
+	cfg, err := config.LoadAgent(path)
+	if err != nil {
+		return nil, err
+	}
+	setupLog(cfg.DataDir)
+	return agent.New(cfg)
+}
+func runConsole(path string) error {
+	app, err := loadApp(path)
+	if err != nil {
+		return err
+	}
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+	return app.Run(ctx)
+}
+
+type serviceHandler struct{ path string }
+
+func (h *serviceHandler) Execute(args []string, requests <-chan svc.ChangeRequest, status chan<- svc.Status) (bool, uint32) {
+	const accepts = svc.AcceptStop | svc.AcceptShutdown
+	status <- svc.Status{State: svc.StartPending}
+	app, err := loadApp(h.path)
+	if err != nil {
+		return false, 1
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	done := make(chan error, 1)
+	go func() { done <- app.Run(ctx) }()
+	status <- svc.Status{State: svc.Running, Accepts: accepts}
+	for {
+		select {
+		case c := <-requests:
+			switch c.Cmd {
+			case svc.Interrogate:
+				status <- c.CurrentStatus
+			case svc.Stop, svc.Shutdown:
+				status <- svc.Status{State: svc.StopPending}
+				cancel()
+				select {
+				case <-done:
+				case <-time.After(10 * time.Second):
+				}
+				return false, 0
+			}
+		case err := <-done:
+			if err != nil {
+				log.Printf("service stopped: %v", err)
+				return false, 1
+			}
+			return false, 0
+		}
+	}
+}
+func runAsService(path string) error { return svc.Run(serviceName, &serviceHandler{path: path}) }
+func installService(path string) error {
+	m, err := mgr.Connect()
+	if err != nil {
+		return err
+	}
+	defer m.Disconnect()
+	if s, err := m.OpenService(serviceName); err == nil {
+		s.Close()
+		return fmt.Errorf("service already exists")
+	}
+	exe, err := os.Executable()
+	if err != nil {
+		return err
+	}
+	s, err := m.CreateService(serviceName, exe, mgr.Config{DisplayName: "SessionGuard Agent", Description: "SessionGuard Terminal Server Agent", StartType: mgr.StartAutomatic}, "-config", path, "-service", "run")
+	if err != nil {
+		return err
+	}
+	defer s.Close()
+	return nil
+}
+func uninstallService() error {
+	m, err := mgr.Connect()
+	if err != nil {
+		return err
+	}
+	defer m.Disconnect()
+	s, err := m.OpenService(serviceName)
+	if err != nil {
+		return err
+	}
+	defer s.Close()
+	return s.Delete()
+}
+func startService() error {
+	m, err := mgr.Connect()
+	if err != nil {
+		return err
+	}
+	defer m.Disconnect()
+	s, err := m.OpenService(serviceName)
+	if err != nil {
+		return err
+	}
+	defer s.Close()
+	return s.Start()
+}
+func stopService() error {
+	m, err := mgr.Connect()
+	if err != nil {
+		return err
+	}
+	defer m.Disconnect()
+	s, err := m.OpenService(serviceName)
+	if err != nil {
+		return err
+	}
+	defer s.Close()
+	_, err = s.Control(svc.Stop)
+	return err
+}

cmd/master/main.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"log"
+	"os/signal"
+	"syscall"
+
+	"github.com/example/sessionguard/internal/config"
+	"github.com/example/sessionguard/internal/master"
+)
+
+func main() {
+	cfgPath := flag.String("config", "/etc/sessionguard/master.json", "master config path")
+	flag.Parse()
+	cfg, err := config.LoadMaster(*cfgPath)
+	if err != nil {
+		log.Fatal(err)
+	}
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+	app, err := master.New(ctx, cfg)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := app.Run(ctx); err != nil {
+		log.Fatal(err)
+	}
+}