Better VM runtime logic

cmd/runvm/runvm.go

@@ -0,0 +1,125 @@
+package runvm
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+
+	"log/slog"
+
+	"github.com/AlexSSD7/linsk/share"
+	"github.com/AlexSSD7/linsk/vm"
+)
+
+type RunVMFunc func(context.Context, *vm.VM, *vm.FileManager, *share.NetTapRuntimeContext) int
+
+func RunVM(vi *vm.VM, initFileManager bool, tapRuntimeCtx *share.NetTapRuntimeContext, fn RunVMFunc) int {
+	runErrCh := make(chan error, 1)
+	var wg sync.WaitGroup
+
+	ctx, ctxCancel := context.WithCancel(context.Background())
+	defer ctxCancel()
+
+	interrupt := make(chan os.Signal, 2)
+	signal.Notify(interrupt, syscall.SIGTERM, syscall.SIGINT)
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		err := vi.Run()
+		ctxCancel()
+		runErrCh <- err
+	}()
+
+	go func() {
+		for i := 0; ; i++ {
+			select {
+			case <-ctx.Done():
+				signal.Reset()
+				return
+			case sig := <-interrupt:
+				lg := slog.With("signal", sig)
+
+				switch {
+				case i == 0:
+					lg.Warn("Caught interrupt, safely shutting down")
+				case i < 10:
+					lg.Warn("Caught subsequent interrupt, please interrupt n more times to panic", "n", 10-i)
+				default:
+					panic("force interrupt")
+				}
+
+				err := vi.Cancel()
+				if err != nil {
+					lg.Warn("Failed to cancel VM context", "error", err.Error())
+				}
+			}
+		}
+	}()
+
+	var fm *vm.FileManager
+	if initFileManager {
+		fm = vm.NewFileManager(slog.Default().With("caller", "file-manager"), vi)
+	}
+
+	for {
+		select {
+		case err := <-runErrCh:
+			if err == nil {
+				err = fmt.Errorf("operation canceled by user")
+			}
+
+			slog.Error("Failed to start the VM", "error", err.Error())
+			return 1
+		case <-vi.SSHUpNotifyChan():
+			if fm != nil {
+				err := fm.Init()
+				if err != nil {
+					slog.Error("Failed to initialize File Manager", "error", err.Error())
+					return 1
+				}
+			}
+
+			startupFailed := false
+
+			if tapRuntimeCtx != nil {
+				err := vi.ConfigureInterfaceStaticNet(context.Background(), "eth1", tapRuntimeCtx.Net.GuestCIDR)
+				if err != nil {
+					slog.Error("Failed to configure tag interface network", "error", err.Error())
+					startupFailed = true
+				}
+			}
+
+			var exitCode int
+
+			if !startupFailed {
+				exitCode = fn(ctx, vi, fm, tapRuntimeCtx)
+			} else {
+				exitCode = 1
+			}
+
+			err := vi.Cancel()
+			if err != nil {
+				slog.Error("Failed to cancel VM context", "error", err.Error())
+				return 1
+			}
+
+			wg.Wait()
+
+			select {
+			case err := <-runErrCh:
+				if err != nil {
+					slog.Error("Failed to run the VM", "error", err.Error())
+					return 1
+				}
+			default:
+			}
+
+			return exitCode
+		}
+	}
+}