libct: add/use configs.HasHook

libcontainer/configs/config.go

@@ -332,6 +332,19 @@ const (
 	Poststop HookName = "poststop"
 )
 
+// HasHook checks if config has any hooks with any given names configured.
+func (c *Config) HasHook(names ...HookName) bool {
+	if c.Hooks == nil {
+		return false
+	}
+	for _, h := range names {
+		if len(c.Hooks[h]) > 0 {
+			return true
+		}
+	}
+	return false
+}
+
 // KnownHookNames returns the known hook names.
 // Used by `runc features`.
 func KnownHookNames() []string {

libcontainer/container_linux.go

@@ -350,7 +350,7 @@ func (c *Container) start(process *Process) (retErr error) {
 
 	if process.Init {
 		c.fifo.Close()
-		if c.config.Hooks != nil {
+		if c.config.HasHook(configs.Poststart) {
 			s, err := c.currentOCIState()
 			if err != nil {
 				return err

libcontainer/criu_linux.go

@@ -1113,7 +1113,7 @@ func (c *Container) criuNotifications(resp *criurpc.CriuResp, process *Process,
 			return err
 		}
 	case "setup-namespaces":
-		if c.config.Hooks != nil {
+		if c.config.HasHook(configs.Prestart, configs.CreateRuntime) {
 			s, err := c.currentOCIState()
 			if err != nil {
 				return nil

libcontainer/process_linux.go

@@ -615,9 +615,16 @@ func (p *initProcess) start() (retErr error) {
 	if err := p.createNetworkInterfaces(); err != nil {
 		return fmt.Errorf("error creating network interfaces: %w", err)
 	}
-	if err := p.updateSpecState(); err != nil {
-		return fmt.Errorf("error updating spec state: %w", err)
+
+	// initConfig.SpecState is only needed to run hooks that are executed
+	// inside a container, i.e. CreateContainer and StartContainer.
+	if p.config.Config.HasHook(configs.CreateContainer, configs.StartContainer) {
+		p.config.SpecState, err = p.container.currentOCIState()
+		if err != nil {
+			return fmt.Errorf("error getting current state: %w", err)
+		}
 	}
+
 	if err := utils.WriteJSON(p.comm.initSockParent, p.config); err != nil {
 		return fmt.Errorf("error sending config to init process: %w", err)
 	}
@@ -740,7 +747,7 @@ func (p *initProcess) start() (retErr error) {
 					return fmt.Errorf("error setting Intel RDT config for procHooks process: %w", err)
 				}
 			}
-			if len(p.config.Config.Hooks) != 0 {
+			if p.config.Config.HasHook(configs.Prestart, configs.CreateRuntime) {
 				s, err := p.container.currentOCIState()
 				if err != nil {
 					return err
@@ -779,16 +786,6 @@ func (p *initProcess) start() (retErr error) {
 	return nil
 }
 
-func (p *initProcess) updateSpecState() error {
-	s, err := p.container.currentOCIState()
-	if err != nil {
-		return err
-	}
-
-	p.config.SpecState = s
-	return nil
-}
-
 func (p *initProcess) createNetworkInterfaces() error {
 	for _, config := range p.config.Config.Networks {
 		strategy, err := getStrategy(config.Type)

libcontainer/rootfs_linux.go

@@ -195,11 +195,12 @@ func prepareRootfs(pipe *syncSocket, iConfig *initConfig) (err error) {
 		return &os.PathError{Op: "chdir", Path: config.Rootfs, Err: err}
 	}
 
-	s := iConfig.SpecState
-	s.Pid = unix.Getpid()
-	s.Status = specs.StateCreating
-	if err := iConfig.Config.Hooks.Run(configs.CreateContainer, s); err != nil {
-		return err
+	if s := iConfig.SpecState; s != nil {
+		s.Pid = unix.Getpid()
+		s.Status = specs.StateCreating
+		if err := iConfig.Config.Hooks.Run(configs.CreateContainer, s); err != nil {
+			return err
+		}
 	}
 
 	if config.NoPivotRoot {

libcontainer/standard_init_linux.go

@@ -267,11 +267,12 @@ func (l *linuxStandardInit) Init() error {
 	// https://github.com/torvalds/linux/blob/v4.9/fs/exec.c#L1290-L1318
 	_ = l.fifoFile.Close()
 
-	s := l.config.SpecState
-	s.Pid = unix.Getpid()
-	s.Status = specs.StateCreated
-	if err := l.config.Config.Hooks.Run(configs.StartContainer, s); err != nil {
-		return err
+	if s := l.config.SpecState; s != nil {
+		s.Pid = unix.Getpid()
+		s.Status = specs.StateCreated
+		if err := l.config.Config.Hooks.Run(configs.StartContainer, s); err != nil {
+			return err
+		}
 	}
 
 	// Close all file descriptors we are not passing to the container. This is