Fall back to /tmp/ dir if $HOME/.cache cannot be used for sensor cache

lib/src/sensorconfig.cpp

@@ -1951,23 +1951,30 @@ SCError SensorConfigImpl::findSensorCachePath(std::string &path) {
         _clusterName = "";
         return SC_UNKNOWNERROR;
     }
-        
-    // Retrieving home dir
-    if((homeDir = getenv("HOME")) == "") {
-        return SC_PATHERROR;
-    }
-    
-    path = homeDir + "/.cache/";
-    // Cache dir does not exist - we create it
-    if(access(path.c_str(), F_OK) != 0 && mkdir(path.c_str(), 0700) != 0)  {
-        path = "";
-        return SC_PATHERROR;
-    }
+      
+    try {
+        // Retrieving home dir
+        if ((homeDir = getenv("HOME")) == "") {
+            throw std::domain_error("Home directory is not defined!");
+        }
+
+        path = homeDir + "/.cache/";
+        // Cache dir does not exist - we create it
+        if (access(path.c_str(), F_OK) != 0 && mkdir(path.c_str(), 0700) != 0) {
+            throw std::domain_error("Cache directory cannot be accessed!");
+        }
 
-    // Cache dir exists but it is not accessible
-    if(access(path.c_str(), W_OK) != 0) { 
-        path = "";
-        return SC_PATHERROR;
+        // Cache dir exists but it is not writeable
+        if (access(path.c_str(), W_OK) != 0) {
+            throw std::runtime_error("Cache directory is not writeable!");
+        }
+    } catch(const std::domain_error& e) {
+        path = "/tmp/";
+        // Tmp dir exists but it is not writeable
+        if (access(path.c_str(), W_OK) != 0) {
+            path = "";
+            return SC_PATHERROR;
+        }
     }
     
     path += std::string(SENSOR_CACHE_FILENAME) + _clusterName;