[log] add build option OT_LOG_MAX_SIZE to set the max log string size (#10948)

etc/cmake/options.cmake

@@ -333,6 +333,7 @@ ot_string_option(OT_VENDOR_SW_VERSION OPENTHREAD_CONFIG_NET_DIAG_VENDOR_SW_VERSI
 set(OT_POWER_SUPPLY_VALUES "BATTERY" "EXTERNAL" "EXTERNAL_STABLE" "EXTERNAL_UNSTABLE")
 ot_multi_option(OT_POWER_SUPPLY OT_POWER_SUPPLY_VALUES OPENTHREAD_CONFIG_DEVICE_POWER_SUPPLY OT_POWER_SUPPLY_ "set the device power supply config")
 
+ot_int_option(OT_LOG_MAX_SIZE OPENTHREAD_CONFIG_LOG_MAX_SIZE "set maximum log string size")
 ot_int_option(OT_MAC_CSL_REQUEST_AHEAD_US OPENTHREAD_CONFIG_MAC_CSL_REQUEST_AHEAD_US "set time ahead to deliver CSL frame from MAC to SubMac in microseconds")
 ot_int_option(OT_MLE_MAX_CHILDREN OPENTHREAD_CONFIG_MLE_MAX_CHILDREN "set maximum number of children")
 ot_int_option(OT_RCP_RESTORATION_MAX_COUNT OPENTHREAD_SPINEL_CONFIG_RCP_RESTORATION_MAX_COUNT "set max RCP restoration count")

examples/platforms/simulation/logging.c

@@ -101,7 +101,7 @@ void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat
 
     if (sLogFile == NULL)
     {
-        char logString[512];
+        char logString[12 /* NodeId */ + OPENTHREAD_CONFIG_LOG_MAX_SIZE];
         int  offset;
 
         offset = snprintf(logString, sizeof(logString), "[%lu]", (unsigned long)gNodeId);

examples/platforms/utils/logging_rtt.h

@@ -93,7 +93,8 @@ extern "C" {
  * stack.
  */
 #ifndef LOG_PARSE_BUFFER_SIZE
-#define LOG_PARSE_BUFFER_SIZE 128
+#define LOG_PARSE_BUFFER_SIZE \
+    (19 /* Timestamp */ + 8 /* RTT color code */ + OPENTHREAD_CONFIG_LOG_MAX_SIZE + 1 /* \n */)
 #endif
 
 /**