Refactor 'runsc boot' to take container ID as argument

This makes the flow slightly simpler (no need to call
Loader.SetRootContainer). And this is required change to tag
tasks with container ID inside the Sentry.

PiperOrigin-RevId: 214795210
Change-Id: I6ff4af12e73bb07157f7058bb15fd5bb88760884

runsc/boot/controller.go

@@ -171,7 +171,6 @@ func (cm *containerManager) StartRoot(cid *string, _ *struct{}) error {
 	if err := <-cm.startResultChan; err != nil {
 		return fmt.Errorf("failed to start sandbox: %v", err)
 	}
-	cm.l.setRootContainerID(*cid)
 	return nil
 }
 

runsc/boot/loader.go

@@ -142,7 +142,7 @@ func init() {
 
 // New initializes a new kernel loader configured by spec.
 // New also handles setting up a kernel for restoring a container.
-func New(spec *specs.Spec, conf *Config, controllerFD, deviceFD int, goferFDs []int, console bool) (*Loader, error) {
+func New(id string, spec *specs.Spec, conf *Config, controllerFD, deviceFD int, goferFDs []int, console bool) (*Loader, error) {
 	if err := usage.Init(); err != nil {
 		return nil, fmt.Errorf("Error setting up memory usage: %v", err)
 	}
@@ -286,6 +286,9 @@ func New(spec *specs.Spec, conf *Config, controllerFD, deviceFD int, goferFDs []
 		spec:                  spec,
 		startSignalForwarding: startSignalForwarding,
 		rootProcArgs:          procArgs,
+		sandboxID:             id,
+		containerRootTGs:      make(map[string]*kernel.ThreadGroup),
+		execProcesses:         make(map[execID]*kernel.ThreadGroup),
 	}
 	ctrl.manager.l = l
 	return l, nil
@@ -420,10 +423,9 @@ func (l *Loader) run() error {
 		l.rootProcArgs.FDMap.DecRef()
 	}
 
-	if l.execProcesses != nil {
-		return fmt.Errorf("there shouldn't already be a cache of exec'd processes, but found: %v", l.execProcesses)
-	}
-	l.execProcesses = make(map[execID]*kernel.ThreadGroup)
+	l.mu.Lock()
+	l.containerRootTGs[l.sandboxID] = l.k.GlobalInit()
+	l.mu.Unlock()
 
 	// Start signal forwarding only after an init process is created.
 	l.stopSignalForwarding = l.startSignalForwarding()

runsc/boot/loader_test.go

@@ -101,7 +101,7 @@ func createLoader() (*Loader, func(), error) {
 		return nil, nil, err
 	}
 
-	l, err := New(spec, conf, fd, -1 /* device fd */, []int{sandEnd}, false)
+	l, err := New("foo", spec, conf, fd, -1 /* device fd */, []int{sandEnd}, false)
 	if err != nil {
 		cleanup()
 		return nil, nil, err
@@ -129,7 +129,6 @@ func TestRun(t *testing.T) {
 	}()
 
 	// Run the container.
-	l.setRootContainerID("foo")
 	if err := l.Run(); err != nil {
 		t.Errorf("error running container: %v", err)
 	}

runsc/cmd/boot.go

@@ -69,7 +69,7 @@ func (*Boot) Synopsis() string {
 
 // Usage implements subcommands.Command.Usage.
 func (*Boot) Usage() string {
-	return `boot [flags]`
+	return `boot [flags] <container id>`
 }
 
 // SetFlags implements subcommands.Command.SetFlags.
@@ -86,7 +86,7 @@ func (b *Boot) SetFlags(f *flag.FlagSet) {
 // Execute implements subcommands.Command.Execute.  It starts a sandbox in a
 // waiting state.
 func (b *Boot) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
-	if b.specFD == -1 || b.controllerFD == -1 || f.NArg() != 0 {
+	if b.specFD == -1 || b.controllerFD == -1 || f.NArg() != 1 {
 		f.Usage()
 		return subcommands.ExitUsageError
 	}
@@ -138,7 +138,7 @@ func (b *Boot) Execute(_ context.Context, f *flag.FlagSet, args ...interface{})
 	}
 
 	// Create the loader.
-	l, err := boot.New(spec, conf, b.controllerFD, b.deviceFD, b.ioFDs.GetArray(), b.console)
+	l, err := boot.New(f.Arg(0), spec, conf, b.controllerFD, b.deviceFD, b.ioFDs.GetArray(), b.console)
 	if err != nil {
 		Fatalf("error creating loader: %v", err)
 	}

runsc/sandbox/sandbox.go

@@ -460,6 +460,9 @@ func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bund
 		}
 	}
 
+	// Add container as the last argument.
+	cmd.Args = append(cmd.Args, s.ID)
+
 	// Log the fds we are donating to the sandbox process.
 	for i, f := range cmd.ExtraFiles {
 		log.Debugf("Donating FD %d: %q", i+3, f.Name())