module_parent_bar.js

var myFunc = require("./myFunc");
(function bar(){
	myFunc("bar message");
})();

module_parent_foo.js

var myFunc = require("./myFunc");
(function foo(){
	myFunc("foo message");
})();

module_parent_myFunc.js

function myFunc(arg){
	console.log(arg);
	console.log(module.parent.filename);
	// Here I need the file path of the caller function
	// For example, "/path/to/foo.js" and "/path/to/bar.js"
}

module.exports = myFunc;