Add mutex/semaphore for logging - protects new logging_buffer

tasmota/support.ino

@@ -111,6 +111,94 @@ String GetResetReason(void)
   }
 }
 
+
+/*********************************************************************************************\
+ * ESP32 AutoMutex
+\*********************************************************************************************/
+
+//////////////////////////////////////////
+// automutex.
+// create a mute in your driver with:
+// void *mutex = nullptr;
+// TasAutoMutex::init(&mutex);
+//
+// then protect any function with
+// TasAutoMutex m(mutex);
+// - it will be automagically released when the function is over.
+// - the same thread can take multiple times (recursive).
+// - advanced options m.give() and m.take() allow you fine control within a function.
+class TasAutoMutex {
+#ifdef ESP32
+  SemaphoreHandle_t mutex;
+#endif
+  bool taken;
+  public:
+    TasAutoMutex(void * mutex, bool take=true);
+    ~TasAutoMutex();
+    void give();
+    void take();
+    static void init(void ** ptr);
+};
+//////////////////////////////////////////
+
+TasAutoMutex::TasAutoMutex(void * mutex, bool take){
+#ifdef ESP32
+  if(mutex){
+    if (take){
+      xSemaphoreTakeRecursive(mutex, portMAX_DELAY);
+      this->taken = true;
+    }
+    this->mutex = (SemaphoreHandle_t ) mutex;
+  } else {
+    this->mutex = (SemaphoreHandle_t )nullptr;
+  }
+#endif  
+}
+
+TasAutoMutex::~TasAutoMutex(){
+#ifdef ESP32
+  if (this->mutex){
+    if (this->taken){
+      xSemaphoreGiveRecursive(this->mutex);
+      this->taken = false;
+    }
+  }
+#endif
+}
+
+void TasAutoMutex::init(void ** ptr){
+#ifdef ESP32
+  SemaphoreHandle_t mutex = xSemaphoreCreateRecursiveMutex();
+  (*ptr) = (void *) mutex;
+#else
+  // needed, else we will initialis more than once in logging
+  (*ptr) = (void *) 1;
+#endif
+}
+
+void TasAutoMutex::give(){
+#ifdef ESP32
+  if (this->mutex){
+    if (this->taken){
+      xSemaphoreGiveRecursive(this->mutex);
+      this->taken= false;
+    }
+  }
+#endif
+}
+void TasAutoMutex::take(){
+#ifdef ESP32
+  if (this->mutex){
+    if (!this->taken){
+      xSemaphoreTakeRecursive(this->mutex, portMAX_DELAY);
+      this->taken = true;
+    }
+  }
+#endif
+}
+
+
+
 /*********************************************************************************************\
  * Miscellaneous
 \*********************************************************************************************/
@@ -1958,6 +2046,10 @@ void SyslogAsync(bool refresh) {
 }
 
 bool NeedLogRefresh(uint32_t req_loglevel, uint32_t index) {
+  // this takes the mutex, and will be release when the class is destroyed - 
+  // i.e. when the functon leaves  You CAN call mutex.give() to leave early.
+  TasAutoMutex mutex(TasmotaGlobal.log_buffer_mutex); 
+
   // Skip initial buffer fill
   if (strlen(TasmotaGlobal.log_buffer) < LOG_BUFFER_SIZE - LOGSZ) { return false; }
 
@@ -1973,6 +2065,10 @@ bool GetLog(uint32_t req_loglevel, uint32_t* index_p, char** entry_pp, size_t* l
   if (TasmotaGlobal.uptime < 3) { return false; }  // Allow time to setup correct log level
   if (!req_loglevel || (index == TasmotaGlobal.log_buffer_pointer)) { return false; }
 
+  // this takes the mutex, and will be release when the class is destroyed - 
+  // i.e. when the functon leaves  You CAN call mutex.give() to leave early.
+  TasAutoMutex mutex(TasmotaGlobal.log_buffer_mutex); 
+
   if (!index) {                            // Dump all
     index = TasmotaGlobal.log_buffer_pointer +1;
     if (index > 255) { index = 1; }
@@ -2011,9 +2107,18 @@ bool GetLog(uint32_t req_loglevel, uint32_t* index_p, char** entry_pp, size_t* l
 }
 
 void AddLogData(uint32_t loglevel, const char* log_data) {
+
+  if (!TasmotaGlobal.log_buffer_mutex){
+    TasAutoMutex::init(&TasmotaGlobal.log_buffer_mutex);
+  }
+
   char mxtime[14];  // "13:45:21.999 "
   snprintf_P(mxtime, sizeof(mxtime), PSTR("%02d" D_HOUR_MINUTE_SEPARATOR "%02d" D_MINUTE_SECOND_SEPARATOR "%02d.%03d "), RtcTime.hour, RtcTime.minute, RtcTime.second, RtcMillis());
 
+  // this takes the mutex, and will be release when the class is destroyed - 
+  // i.e. when the functon leaves  You CAN call mutex.give() to leave early.
+  TasAutoMutex mutex(TasmotaGlobal.log_buffer_mutex); 
+
   if ((loglevel <= TasmotaGlobal.seriallog_level) &&
       (TasmotaGlobal.masterlog_level <= TasmotaGlobal.seriallog_level)) {
     Serial.printf("%s%s\r\n", mxtime, log_data);

tasmota/tasmota.ino

@@ -171,6 +171,7 @@ struct {
   char mqtt_topic[TOPSZ];                   // Composed MQTT topic
   char mqtt_data[MESSZ];                    // MQTT publish buffer and web page ajax buffer
   char log_buffer[LOG_BUFFER_SIZE];         // Web log buffer
+  void *log_buffer_mutex;                   // control, access to log buffer
 } TasmotaGlobal;
 
 #ifdef SUPPORT_IF_STATEMENT