增加sql的waf功能

resty/random.lua

@@ -0,0 +1,36 @@
+-- Copyright (C) by Yichun Zhang (agentzh)
+
+
+local ffi = require "ffi"
+local ffi_new = ffi.new
+local ffi_str = ffi.string
+local C = ffi.C
+--local setmetatable = setmetatable
+--local error = error
+
+
+local _M = { _VERSION = '0.14' }
+
+
+ffi.cdef[[
+int RAND_bytes(unsigned char *buf, int num);
+int RAND_pseudo_bytes(unsigned char *buf, int num);
+]]
+
+
+function _M.bytes(len, strong)
+    local buf = ffi_new("char[?]", len)
+    if strong then
+        if C.RAND_bytes(buf, len) == 0 then
+            return nil
+        end
+    else
+        C.RAND_pseudo_bytes(buf,len)
+    end
+
+    return ffi_str(buf, len)
+end
+
+
+return _M
+