Check locale in GetUserName

src/impl/getusername.cpp

@@ -1,8 +1,33 @@
 #include "getusername.h"
+#include <errno.h>
+#include <langinfo.h>
+#include <locale.h>
 #include <unistd.h>
+#include <string>
 
+using namespace std;
+
+const string utf8 = "UTF-8";
+
+// https://msdn.microsoft.com/en-us/library/windows/desktop/ms724432(v=vs.85).aspx
+// Sets errno to:
+//     ERROR_BAD_ENVIRONMENT - locale is not UTF-8
+//
+// Returns:
+//     1 - succeeded
+//     0 - failed
 BOOL GetUserName(WCHAR_T* lpBuffer, LPDWORD lpnSize)
 {
-	return 0;
+	errno = 0;
+
+	// Select locale from environment
+	setlocale(LC_ALL, "");
+	// Check that locale is UTF-8
+	if (nl_langinfo(CODESET) != utf8) {
+		errno = ERROR_BAD_ENVIRONMENT;
+		return 0;
+	}
+
+	return 1;
 }
 

src/impl/pal.h

@@ -71,6 +71,7 @@
     #define FALSE 0
     #define ERROR_INVALID_PARAMETER 87
     #define ERROR_OUTOFMEMORY 14
+    #define ERROR_BAD_ENVIRONMENT 0x0000000A
     #define MAX_PATH 0x00000104
     typedef unsigned long long uint64;
 #endif