diff --git a/regexis024_build_system.h b/regexis024_build_system.h
index 67e094d..16737e9 100644
--- a/regexis024_build_system.h
+++ b/regexis024_build_system.h
@@ -161,6 +161,12 @@ struct path_t {
     }
 };
 
+mode_t get_umask(){
+    mode_t old = umask(0);
+    umask(old);
+    return old;
+}
+
 void createDir(const path_t& path) {
     std::string cur_pref = std::string(path.is_relative ? "" : "/");
     for (size_t i = 0; i < path.parts.size(); i++) {
@@ -170,7 +176,7 @@ void createDir(const path_t& path) {
         stat(cur_pref.c_str(), &info);
         if (errno == ENOENT) {
             /* User : reads, writes, executes; Other: reads, executes; */
-            int ret = mkdir(cur_pref.c_str(), S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
+            int ret = mkdir(cur_pref.c_str(), 0755);
             ASSERT_on_iret(ret, "mkdir(\"" + cur_pref + "\")");
         } else if (errno == 0) {
             if (S_ISDIR(info.st_mode)) {
@@ -332,7 +338,7 @@ void writeToFileDescriptor(int fd, const std::string& text, const std::string& d
 
 /* Truncational */
 void writeFile(const std::string& path, const std::string& text) {
-    int fd = open(path.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0770);
+    int fd = open(path.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0755);
     ASSERT_on_iret(fd, "Opening \"" + path + "\"");
     writeToFileDescriptor(fd, text, "file \"" + path + "\n");
 }
@@ -646,7 +652,7 @@ struct FileInstallBuildUnit: public BuildUnit {
         // todo, fix that func and writeFile() so that output file is set to source size at the beginning
         int rfd = open(((std::string)source).c_str(), O_RDONLY);
         ASSERT_on_iret(rfd, "opening source file to read");
-        int wfd = open(((std::string)destination).c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0770);
+        int wfd = open(((std::string)destination).c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0755);
         ASSERT_on_iret(wfd, "opening destination file to write");
         char buf[2048];
         int sz;
@@ -919,9 +925,7 @@ struct CTarget {
     std::vector<std::string> additional_compilation_flags;
     std::vector<std::string> additional_linkage_flags;
 
-    /* Prefix for all cpp files in `units` array */
-    std::string units_dir;
-    /* .c and .cpp source files relative to the special src/${units_dir} directory*/
+    /* .c and .cpp source files relative to the special src directory*/
     std::vector<std::string> units;
 
     std::string include_pr;
@@ -976,7 +980,7 @@ void check_pkg_conf_rel_install_path(const path_t& P) {
 }
 
 /* Argument `name` is just a name in `units` array, return value is relative to $IR/$TARGET_NAME/obj */
-path_t c_unit_name_to_obj_filename(const std::string& units_dir, const std::string& PtoC) {
+path_t c_unit_name_to_obj_filename(const std::string& PtoC) {
     path_t P(PtoC);
     assert(!P.parts.empty());
     std::string& filename = P.parts.back();
@@ -992,8 +996,8 @@ path_t c_unit_name_to_obj_filename(const std::string& units_dir, const std::stri
     return P;
 }
 
-path_t c_unit_name_to_source_filename(const std::string& units_dir, const std::string& PtoC){
-    return path_t(units_dir) / PtoC;
+path_t c_unit_name_to_source_filename(const std::string& PtoC){
+    return path_t(PtoC);
 }
 
 void load_ctargets_on_building_and_installing(
@@ -1049,10 +1053,10 @@ void load_ctargets_on_building_and_installing(
         size_t mk_personal_targ_dir_bu_id = add_bbu(new MkdirBuildUnit(path_t(proj_compiled_dir_path) / tg.name));
         std::vector<size_t> all_comp_units_bu_ids;
         auto BU_to_SOURCE_FILEPATH = [&](const std::string& bu) -> path_t {
-            return path_t(proj_src_dir_path) / c_unit_name_to_source_filename(tg.units_dir, bu);
+            return path_t(proj_src_dir_path) / c_unit_name_to_source_filename(bu);
         };
         auto BU_to_OBJ_FILEPATH = [&](const std::string& bu) -> path_t {
-            return path_t(proj_compiled_dir_path) / tg.name / "obj" / c_unit_name_to_obj_filename(tg.units_dir, bu);
+            return path_t(proj_compiled_dir_path) / tg.name / "obj" / c_unit_name_to_obj_filename(bu);
         };
         auto generate_cu_BUs = [&](const std::vector<std::string>& ctg_type_intrinsic_comp_args) {
             const std::string comp_cmd = "g++"; // todo: think of some other way around