demo server for RPI: reading cpu temperature works

BTW, it will work on almost any newer linux kernel - no rpu specific code yet
relates to #165

CMakeLists.txt

@@ -169,6 +169,21 @@ if(EXAMPLESERVER)
     endif()
 endif()
 
+# build rpi example server
+option(EXAMPLESERVER_RPI "Build a Raspberry Pi specific test server" OFF)
+if(EXAMPLESERVER_RPI)
+    add_executable(exampleServerRpi examples/server_rpi.c examples/networklayer_tcp.c examples/logger_stdout.c ${exported_headers} ${generated_headers})
+    target_link_libraries(exampleServerRpi open62541-static)
+    if(WIN32)
+        target_link_libraries(exampleServerRpi ws2_32)
+    else()
+        target_link_libraries(exampleServerRpi rt)
+    endif()
+    if(MULTITHREADING)
+        target_link_libraries(exampleServerRpi urcu-cds urcu urcu-common pthread)
+    endif()
+endif()
+
 ## self-signed certificates
 option(GENERATE_SELFSIGNED "Generate self-signed certificates" OFF)
 if(GENERATE_SELFSIGNED)

examples/server_rpi.c

@@ -0,0 +1,98 @@
+/*
+ * This work is licensed under a Creative Commons CCZero 1.0 Universal License.
+ * See http://creativecommons.org/publicdomain/zero/1.0/ for more information.
+ */
+#include <time.h>
+#include "ua_types.h"
+
+#include <stdio.h>
+#include <stdlib.h> 
+#include <signal.h>
+#define __USE_XOPEN2K
+#include <pthread.h>
+
+// provided by the open62541 lib
+#include "ua_server.h"
+
+// provided by the user, implementations available in the /examples folder
+#include "logger_stdout.h"
+#include "networklayer_tcp.h"
+
+FILE* temperatureFile;
+UA_Boolean running = 1;
+UA_Logger logger;
+
+/*************************/
+/* Read-only temperature */
+/*************************/
+static UA_StatusCode readTemperature(const void *handle, UA_DataValue *value) {
+    UA_Double* currentTemperature = UA_Double_new();
+    UA_Int32 i = 0;
+    if(!currentTemperature)
+        return UA_STATUSCODE_BADOUTOFMEMORY;
+
+
+    if (fseek(temperatureFile, 0, SEEK_SET))
+      {
+        puts("Error seeking to start of file");
+        exit(1);
+      }
+
+    if(fscanf(temperatureFile, "%d", &i) != 1){
+    	printf("Can not open parse temperature!\n");
+    	exit(1);
+    }
+
+    *currentTemperature = i/1000.0;
+
+    value->value.type = &UA_TYPES[UA_TYPES_DOUBLE];
+    value->value.arrayLength = 1;
+    value->value.dataPtr = currentTemperature;
+    value->value.arrayDimensionsSize = -1;
+    value->value.arrayDimensions = NULL;
+    value->hasVariant = UA_TRUE;
+    return UA_STATUSCODE_GOOD;
+}
+
+static void releaseTemperature(const void *handle, UA_DataValue *value) {
+    UA_Double_delete((UA_Double*)value->value.dataPtr);
+}
+
+static void stopHandler(int sign) {
+    printf("Received Ctrl-C\n");
+	running = 0;
+}
+
+int main(int argc, char** argv) {
+	signal(SIGINT, stopHandler); /* catches ctrl-c */
+
+	UA_Server *server = UA_Server_new();
+    logger = Logger_Stdout_new();
+    UA_Server_setLogger(server, logger);
+    UA_Server_addNetworkLayer(server, ServerNetworkLayerTCP_new(UA_ConnectionConfig_standard, 16664));
+
+    if(!(temperatureFile = fopen("/sys/class/thermal/thermal_zone0/temp", "r"))){
+    	printf("Can not open temperature file!\n");
+    	exit(1);
+    }
+
+    // add node with the datetime data source
+    UA_DataSource temperatureDataSource = (UA_DataSource)
+        {.handle = NULL,
+         .read = readTemperature,
+         .release = releaseTemperature,
+         .write = NULL};
+    UA_QualifiedName dateName;
+    UA_QUALIFIEDNAME_ASSIGN(dateName, "cpu temperature");
+    UA_Server_addDataSourceVariableNode(server, temperatureDataSource, &UA_NODEID_NULL, &dateName,
+                                        &UA_NODEID_STATIC(0, UA_NS0ID_OBJECTSFOLDER),
+                                        &UA_NODEID_STATIC(0, UA_NS0ID_ORGANIZES));
+
+    UA_StatusCode retval = UA_Server_run(server, 1, &running);
+	UA_Server_delete(server);
+
+    fclose(temperatureFile);
+
+
+	return retval;
+}