Use process group IDs for terminating service subprocesses

services/agetty-tty1.esv

@@ -4,4 +4,5 @@ type: background
 start_cmd: /usr/bin/setsid /sbin/agetty --noclear tty1
 exit_method: kill
 crash_on_safe_exit: false
-restart: always
+restart: always
+setpgid: false

services/agetty-tty2.esv

@@ -4,4 +4,5 @@ type: background
 start_cmd: /usr/bin/setsid /sbin/agetty tty2
 exit_method: kill
 crash_on_safe_exit: false
-restart: always
+restart: always
+setpgid: false

services/agetty-tty3.esv

@@ -4,4 +4,5 @@ type: background
 start_cmd: /usr/bin/setsid /sbin/agetty tty3
 exit_method: kill
 crash_on_safe_exit: false
-restart: always
+restart: always
+setpgid: false

services/agetty-tty4.esv

@@ -4,4 +4,5 @@ type: background
 start_cmd: /usr/bin/setsid /sbin/agetty tty4
 exit_method: kill
 crash_on_safe_exit: false
-restart: always
+restart: always
+setpgid: false

services/agetty-tty5.esv

@@ -4,4 +4,5 @@ type: background
 start_cmd: /usr/bin/setsid /sbin/agetty tty5
 exit_method: kill
 crash_on_safe_exit: false
-restart: always
+restart: always
+setpgid: false

services/agetty-tty6.esv

@@ -4,4 +4,5 @@ type: background
 start_cmd: /usr/bin/setsid /sbin/agetty tty6
 exit_method: kill
 crash_on_safe_exit: false
-restart: always
+restart: always
+setpgid: false

src/ectl/main.go

@@ -57,7 +57,59 @@ func main() {
 		return
 	} else if flag.Args()[0] == "service" || flag.Args()[0] == "sv" {
 		if len(flag.Args()) <= 1 {
-			fmt.Println("Usage: ectl service <start/stop/enable/disable/status/list> [service]")
+			fmt.Println("Usage: ectl service <reload/start/stop/enable/disable/status/list> [service]")
+			return
+		}
+		if flag.Arg(1) == "reload" {
+			type ServiceCommandJsonStruct struct {
+				Command string `json:"command"`
+				Service string `json:"service"`
+			}
+			serviceCommandJson := ServiceCommandJsonStruct{
+				Command: flag.Arg(1),
+			}
+
+			// Encode struct to json string
+			jsonData, err := json.Marshal(serviceCommandJson)
+			if err != nil {
+				log.Fatalf("Could not encode JSON data! Error: %s\n", err)
+			}
+
+			_, err = conn.Write(jsonData)
+			if err != nil {
+				log.Fatalf("Could not write JSON data to socket! Error: %s\n", err)
+			}
+
+			// Create a buffer for incoming data.
+			buf := make([]byte, 4096)
+
+			// Read data from the connection.
+			n, err := conn.Read(buf)
+			if err != nil {
+				return
+			}
+
+			// Print json data if flag is set
+			if *printJson {
+				fmt.Println(string(buf[:n]))
+				return
+			}
+
+			// Decoode JSON data
+			var returnedJsonData map[string]any
+			err = json.Unmarshal(buf[:n], &returnedJsonData)
+			if err != nil {
+				log.Fatalf("Could not decode JSON data from connection!")
+			}
+
+			if err, ok := returnedJsonData["error"]; ok {
+				log.Fatal(err)
+			} else if msg, ok := returnedJsonData["success"]; ok {
+				fmt.Println(msg)
+			} else {
+				log.Fatal("Connection returned empty string!")
+			}
+
 			return
 		} else if flag.Arg(1) == "start" || flag.Arg(1) == "stop" || flag.Arg(1) == "restart" {
 			// Ensure service name argument has been set

src/enit/main.go

@@ -215,16 +215,12 @@ func waitZombieProcesses() {
 func catchSignals() {
 	sigc := make(chan os.Signal, 1)
 	signal.Notify(sigc, syscall.SIGUSR1, syscall.SIGTERM, syscall.SIGINT, syscall.SIGCHLD)
-	defer close(sigc)
-	defer signal.Stop(sigc)
 	for {
 		switch <-sigc {
 		case syscall.SIGUSR1:
-			close(sigc)
 			signal.Stop(sigc)
 			shutdownSystem()
 		case syscall.SIGTERM, syscall.SIGINT:
-			close(sigc)
 			signal.Stop(sigc)
 			rebootSystem()
 		case syscall.SIGCHLD:

src/esvm/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"crypto/sha256"
 	"flag"
 	"fmt"
 	"io"
@@ -143,19 +144,22 @@ func Init() {
 			}
 
 			service := EnitService{
-				Name:            "",
-				Description:     "",
-				Dependencies:    make([]string, 0),
-				Type:            "",
-				StartCmd:        "",
-				ExitMethod:      "",
-				StopCmd:         "",
-				Restart:         "",
-				CrashOnSafeExit: true,
-				restartCount:    0,
-				stopChannel:     make(chan bool),
-				LogOutput:       true,
-				state:           EnitServiceUnloaded,
+				Name:             "",
+				Description:      "",
+				Dependencies:     make([]string, 0),
+				Type:             "",
+				StartCmd:         "",
+				ExitMethod:       "",
+				StopCmd:          "",
+				Restart:          "",
+				Setpgid:          true,
+				CrashOnSafeExit:  true,
+				LogOutput:        true,
+				Filepath:         path.Join(serviceConfigDir, "services", entry.Name()),
+				filepathChecksum: sha256.Sum256(bytes),
+				restartCount:     0,
+				stopChannel:      make(chan bool),
+				state:            EnitServiceUnloaded,
 			}
 			if err := yaml.Unmarshal(bytes, &service); err != nil {
 				logger.Printf("Error: could not read service file %s", path.Join(serviceConfigDir, "services", entry.Name()))
@@ -227,6 +231,16 @@ func Init() {
 	logger.Println("ESVM initialized successfully!")
 }
 
+func Reload() {
+	logger.Println("Reloading all ESVM services...")
+
+	for _, service := range Services {
+		service.ReloadService()
+	}
+
+	logger.Println("All ESVM services have been reloaded!")
+}
+
 func Destroy() {
 	logger.Println("Stopping all ESVM services...")
 

src/esvm/service.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"crypto/sha256"
 	"fmt"
+	"io"
 	"os"
 	"os/exec"
 	"path"
@@ -18,6 +20,7 @@ type EnitServiceState uint8
 const (
 	EnitServiceUnknown EnitServiceState = iota
 	EnitServiceUnloaded
+	EnitServiceStarting
 	EnitServiceRunning
 	EnitServiceStopped
 	EnitServiceCrashed
@@ -27,6 +30,7 @@ const (
 var EnitServiceStateNames map[EnitServiceState]string = map[EnitServiceState]string{
 	EnitServiceUnknown:   "unknown",
 	EnitServiceUnloaded:  "unloaded",
+	EnitServiceStarting:  "starting",
 	EnitServiceRunning:   "running",
 	EnitServiceStopped:   "stopped",
 	EnitServiceCrashed:   "crashed",
@@ -34,20 +38,25 @@ var EnitServiceStateNames map[EnitServiceState]string = map[EnitServiceState]str
 }
 
 type EnitService struct {
-	Name            string   `yaml:"name"`
-	Description     string   `yaml:"description,omitempty"`
-	Dependencies    []string `yaml:"dependencies,omitempty"`
-	Type            string   `yaml:"type"`
-	StartCmd        string   `yaml:"start_cmd"`
-	ExitMethod      string   `yaml:"exit_method"`
-	CrashOnSafeExit bool     `yaml:"crash_on_safe_exit"`
-	StopCmd         string   `yaml:"stop_cmd,omitempty"`
-	Restart         string   `yaml:"restart,omitempty"`
-	LogOutput       bool     `yaml:"log_output,omitempty"`
-	state           EnitServiceState
-	processID       int
-	restartCount    int
-	stopChannel     chan bool
+	Name             string   `yaml:"name"`
+	Description      string   `yaml:"description,omitempty"`
+	Dependencies     []string `yaml:"dependencies,omitempty"`
+	Type             string   `yaml:"type"`
+	StartCmd         string   `yaml:"start_cmd"`
+	ExitMethod       string   `yaml:"exit_method"`
+	CrashOnSafeExit  bool     `yaml:"crash_on_safe_exit"`
+	StopCmd          string   `yaml:"stop_cmd,omitempty"`
+	Restart          string   `yaml:"restart,omitempty"`
+	ReadyFd          int      `yaml:"ready_fd"`
+	Setpgid          bool     `yaml:"setpgid"`
+	LogOutput        bool     `yaml:"log_output,omitempty"`
+	Filepath         string
+	filepathChecksum [32]byte
+	state            EnitServiceState
+	processID        int
+	restartCount     int
+	stopChannel      chan bool
+	shouldReload     bool
 }
 
 var Services = make([]*EnitService, 0)
@@ -113,7 +122,92 @@ func (service *EnitService) GetLogFile() (file *os.File, err error) {
 	return file, nil
 }
 
-func (service *EnitService) StartService() error {
+func (service *EnitService) ReloadService() {
+	bytes, err := os.ReadFile(service.Filepath)
+	checksum := sha256.Sum256(bytes)
+	if slices.Equal(checksum[:], service.filepathChecksum[:]) {
+		return
+	}
+
+	if service.state == EnitServiceStarting || service.state == EnitServiceRunning {
+		service.shouldReload = true
+		logger.Printf("Warning: Service (%s) is currently running and will be reloaded when stopped\n", service.Name)
+		return
+	}
+	service.shouldReload = false
+
+	logger.Printf("Reloading service (%s)...\n", service.Filepath)
+
+	if os.IsNotExist(err) {
+		Services = slices.DeleteFunc(Services, func(sv *EnitService) bool {
+			return sv == service
+		})
+		logger.Printf("Service (%s) has been removed\n", service.Name)
+		return
+	} else if err != nil {
+		logger.Printf("Error: Could not read service file (%s)", service.Filepath)
+		return
+	}
+
+	newService := EnitService{
+		Name:             "",
+		Description:      "",
+		Dependencies:     make([]string, 0),
+		Type:             "",
+		StartCmd:         "",
+		ExitMethod:       "",
+		StopCmd:          "",
+		Restart:          "",
+		Setpgid:          true,
+		CrashOnSafeExit:  true,
+		LogOutput:        true,
+		Filepath:         service.Filepath,
+		filepathChecksum: checksum,
+		restartCount:     service.restartCount,
+		stopChannel:      service.stopChannel,
+		state:            service.state,
+	}
+	if err := yaml.Unmarshal(bytes, &newService); err != nil {
+		logger.Printf("Error: could not read service file %s", service.Filepath)
+		return
+	}
+
+	for _, sv := range Services {
+		if sv.Name == newService.Name && sv != service {
+			logger.Printf("Error: service with name (%s) has already been initialized", service.Name)
+		}
+	}
+
+	switch newService.Type {
+	case "simple", "background":
+	default:
+		logger.Printf("Error: unknown service type (%s)", newService.Type)
+		return
+	}
+
+	switch newService.ExitMethod {
+	case "stop_command", "kill":
+	default:
+		logger.Printf("Error: unknown exit method (%s)\n", newService.ExitMethod)
+		return
+	}
+
+	switch newService.Restart {
+	case "true", "always":
+	default:
+		newService.Restart = "false"
+	}
+
+	for i, sv := range Services {
+		if sv == service {
+			Services[i] = &newService
+		}
+	}
+
+	logger.Printf("Service (%s) has been reloaded!\n", newService.Name)
+}
+
+func (service *EnitService) StartService() (err error) {
 	if service == nil {
 		return nil
 	}
@@ -126,7 +220,6 @@ func (service *EnitService) StartService() error {
 	// Get log file if service logs output
 	var logFile *os.File
 	if service.LogOutput {
-		var err error
 		logFile, err = service.GetLogFile()
 		if err != nil {
 			return err
@@ -134,10 +227,38 @@ func (service *EnitService) StartService() error {
 	}
 
 	cmd := exec.Command("/bin/sh", "-c", "exec "+service.StartCmd)
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: service.Setpgid, Pgid: 0}
 	if logFile != nil {
 		cmd.Stdout = logFile
 		cmd.Stderr = logFile
 	}
+	var pipeReader, pipeWriter *os.File
+	if service.ReadyFd > 2 {
+		pipeReader, pipeWriter, err = os.Pipe()
+		if err != nil {
+			// Close log file if not nil
+			if logFile != nil {
+				logFile.Close()
+			}
+
+			return err
+		}
+
+		err := pipeReader.SetDeadline(time.Now().Add(10 * time.Second))
+		if err != nil {
+			// Close log file if not nil
+			if logFile != nil {
+				logFile.Close()
+			}
+
+			return err
+		}
+
+		for i := 3; i < service.ReadyFd; i++ {
+			cmd.ExtraFiles = append(cmd.ExtraFiles, nil)
+		}
+		cmd.ExtraFiles = append(cmd.ExtraFiles, pipeWriter)
+	}
 	if err := cmd.Start(); err != nil {
 		// Close log file if not nil
 		if logFile != nil {
@@ -148,6 +269,28 @@ func (service *EnitService) StartService() error {
 	}
 
 	service.processID = cmd.Process.Pid
+	service.state = EnitServiceStarting
+
+	// Wait for data from pipe
+	if pipeReader != nil {
+		buffer := make([]byte, 1)
+		_, err := io.ReadAtLeast(pipeReader, buffer, 1)
+		if err != nil {
+			// Close log file if not nil
+			if logFile != nil {
+				logFile.Close()
+			}
+
+			// Kill process and children
+			syscall.Kill(-service.processID, syscall.SIGKILL)
+
+			service.processID = 0
+			service.state = EnitServiceCrashed
+
+			return err
+		}
+	}
+
 	service.state = EnitServiceRunning
 
 	go func() {
@@ -162,10 +305,21 @@ func (service *EnitService) StartService() error {
 		case <-service.stopChannel:
 			service.restartCount = 0
 		default:
+			// Kill remaining child processes
+			syscall.Kill(-service.processID, syscall.SIGKILL)
+
 			if service.Type == "simple" && err == nil {
 				service.restartCount = 0
 				if service.ExitMethod != "stop_command" {
 					service.state = EnitServiceCompleted
+
+					// Reload service if needed
+					if service.shouldReload {
+						service.ReloadService()
+						if GetServiceByName(service.Name) == nil {
+							return
+						}
+					}
 				} else {
 					service.state = EnitServiceRunning
 				}
@@ -179,6 +333,15 @@ func (service *EnitService) StartService() error {
 				service.state = EnitServiceCrashed
 			}
 
+			// Reload service if needed
+			if service.shouldReload {
+				service.ReloadService()
+				if GetServiceByName(service.Name) == nil {
+					return
+				}
+				service = GetServiceByName(service.Name)
+			}
+
 			if service.Restart == "always" {
 				_ = service.StartService()
 			} else if service.Restart == "true" && service.restartCount < 5 {
@@ -206,11 +369,24 @@ func (service *EnitService) StopService() error {
 	}
 
 	logger.Printf("Stopping service (%s)...", service.Name)
+	pid := service.processID
 
 	newServiceStatus := EnitServiceCrashed
 	defer func() {
+		// Kill remaining child processes
+		syscall.Kill(-pid, syscall.SIGKILL)
+
 		service.state = newServiceStatus
 		service.processID = 0
+
+		// Reload service if needed
+		if service.shouldReload {
+			service.ReloadService()
+			if GetServiceByName(service.Name) == nil {
+				return
+			}
+			service = GetServiceByName(service.Name)
+		}
 	}()
 
 	if service.ExitMethod == "kill" {

src/esvm/socket.go

@@ -17,6 +17,7 @@ func initSocket() (socket net.Listener, err error) {
 	}
 
 	// Register command handlers
+	commandHandlers["reload"] = handleReloadServicesCommand
 	commandHandlers["start"] = handleStartServiceCommand
 	commandHandlers["stop"] = handleStopServiceCommand
 	commandHandlers["restart"] = handleRestartServiceCommand
@@ -74,6 +75,13 @@ func listenToSocket() {
 	}(conn)
 }
 
+func handleReloadServicesCommand(conn net.Conn, jsonData map[string]any) {
+	// Reload services
+	Reload()
+
+	conn.Write(wrapSuccessMsgInJson("Services reloaded successfully"))
+}
+
 func handleStartServiceCommand(conn net.Conn, jsonData map[string]any) {
 	// Get service name from json data
 	serviceName, ok := jsonData["service"]