win32: implement umask(2)

umask() in the Microsoft C runtime takes different arguments to
umask(2).  Implement a fake umask(2) that remembers the mask and
calls the Microsoft umask() with an appropriate value.

Since the mask won't be inherited by children use an environment
variable to pass any value set by the shell built-in umask.

1 files changed, 14 insertions, 0 deletions

diff --git a/win32/mingw.c b/win32/mingw.c
index 8d1da5199..c72a306ac 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -318,6 +318,20 @@ static inline int get_file_attr(const char *fname, WIN32_FILE_ATTRIBUTE_DATA *fd
         }
 }
 
+#undef umask
+mode_t mingw_umask(mode_t new_mode)
+{
+        static mode_t old_mode = DEFAULT_UMASK;
+        mode_t tmp_mode;
+
+        tmp_mode = old_mode;
+        old_mode = new_mode;
+
+        umask((new_mode & S_IWUSR) ? _S_IWRITE : 0);
+
+        return tmp_mode;
+}
+
 /*
  * Examine a file's contents to determine if it can be executed.  This
  * should be a last resort:  in most cases it's much more efficient to