diff --git a/vlib/os/const.v b/vlib/os/const.v
index 336f661e2d..fda70ac717 100644
--- a/vlib/os/const.v
+++ b/vlib/os/const.v
@@ -73,3 +73,30 @@ const (
     O_SYNC   = 64  // open for synchronous I/O.
     O_TRUNC  = 128 // truncate regular writable file when opened.
 )
+
+// Permission bits
+const (
+	S_IREAD	 = 0400	   /* Read by owner.    */
+	S_IWRITE = 0200	   /* Write by owner.   */
+	S_IEXEC	 = 0100	   /* Execute by owner. */
+
+	S_IRUSR	= S_IREAD  /* Alias of S_IREAD  */
+	S_IWUSR	= S_IWRITE /* Alias of S_IWRITE */
+	S_IXUSR	= S_IEXEC  /* Alias of S_IEXEC  */
+
+	S_IRWXU	= (S_IREAD|S_IWRITE|S_IEXEC)
+
+	S_IRGRP	= (S_IRUSR >> 3)    /* Read by group.                     */
+	S_IWGRP	= (S_IWUSR >> 3)    /* Write by group.                    */
+	S_IXGRP	= (S_IXUSR >> 3)    /* Execute by group.                  */
+	S_IRWXG	= (S_IRWXU >> 3)    /* Read, write, and execute by group. */
+
+	S_IROTH	= (S_IRGRP >> 3)    /* Read by others.                     */
+	S_IWOTH	= (S_IWGRP >> 3)    /* Write by others.                    */
+	S_IXOTH	= (S_IXGRP >> 3)    /* Execute by others.                  */
+	S_IRWXO	= (S_IRWXG >> 3)    /* Read, write, and execute by others. */
+
+	ACCESSPERMS = (S_IRWXU|S_IRWXG|S_IRWXO)                         /* 0777 */
+	ALLPERMS    = (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO) /* 07777 */
+	DEFFILEMODE = (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH) /* 0666*/
+)