diff --git a/libmaxsi/include/sys/stat.h b/libmaxsi/include/sys/stat.h
index 615544e8..d35da270 100644
--- a/libmaxsi/include/sys/stat.h
+++ b/libmaxsi/include/sys/stat.h
@@ -50,6 +50,7 @@ int fchmod(int fd, mode_t mode);
 int fstat(int fd, struct stat* st);
 int mkdir(const char *path, mode_t mode);
 int stat(const char* restrict path, struct stat* restrict st);
+mode_t umask(mode_t mask);
 __END_DECLS
 
 #endif
diff --git a/libmaxsi/io.cpp b/libmaxsi/io.cpp
index 2213ab1d..9d474a23 100644
--- a/libmaxsi/io.cpp
+++ b/libmaxsi/io.cpp
@@ -313,6 +313,12 @@ namespace Maxsi
 		return -1;
 	}
 
+	// TODO: Implement these in the kernel.
+	extern "C" mode_t umask(mode_t mask)
+	{
+		return 0;
+	}
+
 	// TODO: This is a hacky implementation of a stupid function.
 	char* mktemp(char* templ)
 	{