Added sync.

api/modem/modem.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"os/exec"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/CGSG-2021-AE4/modem-test/api/modem/at"
@@ -24,6 +25,7 @@ type ModemData struct {
 type modem struct {
 	// Internal values
 	logger *log.Logger
+	mutex  sync.Mutex
 
 	// Serial values
 	baudrate   int
@@ -71,6 +73,9 @@ func New(logger *log.Logger) Modem {
 }
 
 func (m *modem) Init() error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
 	// Turn module on
 	m.logger.Println("=============================== Turn on module")
 	if err := m.onOffPin.Init(); err != nil {
@@ -138,6 +143,9 @@ func (m *modem) Init() error {
 }
 
 func (m *modem) Update() error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
 	if !m.IsConnected() {
 		m.logger.Println("No connection to module")
 		return nil
@@ -152,6 +160,9 @@ func (m *modem) Update() error {
 }
 
 func (m *modem) GetData() ModemData {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
 	return ModemData{
 		Port: m.port.GetName(),
 		Data: m.gps.GetData(),
@@ -171,6 +182,9 @@ func (m *modem) At() at.Port {
 }
 
 func (m *modem) Close() error { // I can't return error so I log it
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
 	if err := m.sms.Close(); err != nil {
 		m.logger.Printf("\x1b[38;2;255;0;0mclose sms error: %s\x1b[38;2;255;255;255m\n", err.Error())
 	}
@@ -290,6 +304,11 @@ func (m *modem) checkPort(portName string) (outErr error) {
 	}
 	defer m.port.Disconnect() // Do not bother about errors...
 
+	// To filter dead ports
+	if _, err := m.port.Send("AT"); err != nil {
+		return fmt.Errorf("ping error: %w", err)
+	}
+
 	if err := m.setupPort(); err != nil {
 		return fmt.Errorf("setup port: %w", err)
 	}

api/modem/sms/sms.go

@@ -35,6 +35,14 @@ func (d *dialer) Init() error {
 		return fmt.Errorf("serial port is not connected")
 	}
 
+	// Check SIM an PIN
+	if resp, err := d.port.Send("AT+CPIN?"); err != nil || !resp.Check() {
+		if err != nil {
+			return fmt.Errorf("check pin: %w", err)
+		}
+		return fmt.Errorf("check pin: error response: %s", resp)
+	}
+
 	// Ensure text format
 	if resp, err := d.port.Send("AT+CMGF=1"); err != nil || !resp.Check() {
 		if err != nil {