luci 打印函数封装

最近把luci代码深入地剖析了一遍．说实话刚开始看的时候也是云里雾里,特别是dispatch函数, 这其间也是参考了几篇文章, 特此感谢.

刚开始看luci代码确实就和逆向没啥区别,　需要揣摩作者对于各个变量的用途．　于是我就想了一个办法, 就是把每个变量都打印出来.

为此我在/usr/lib/lua/luci目录下引入了log.lua模块:

local M = {}

local tconcat = table.concat
local tinsert = table.insert
local srep = string.rep

local function local_print(str)
local dbg = io.open("/tmp/luci.output", "a+")
local str = str or ""
if dbg then
dbg:write(str..'\n')
dbg:close()
end
end

function M.print(...)
local dbg = io.open("/tmp/luci.output", "a+")
if dbg then
dbg:write(os.date("[%H:%M:%S]: "))
for _, o in ipairs({...}) do
dbg:write(tostring(o)..'  ')
end
dbg:write("\n")
dbg:close()
end
end

function M.print_r(data, depth)
local depth = depth or 3
local cstring = "";
local top_flag = true

local function table_len(t)
local i = 0
for k, v in pairs(t) do
i = i + 1
end
return i
end

local function tableprint(data,cstring, local_depth)
if data == nil then
local_print("core.print data is nil");
end

local cs = cstring .. "    ";
if top_flag then
local_print(cstring .."{");
top_flag = false
end
if(type(data)=="table") then
for k, v in pairs(data) do
if type(v) ~= "table" then
if type(v) == "string" then
local_print(cs..tostring(k).." = ".."'"..tostring(v).."'");
else
local_print(cs..tostring(k).." = "..tostring(v));
end
elseif table_len(v) == 0 then
local_print(cs..tostring(k).." = ".."{}")
elseif local_depth < depth then
local_print(cs..tostring(k).." = {");
tableprint(v,cs,local_depth+1);
else
local_print(cs..tostring(k).." = ".."{*}")
end
end
else
local_print(cs..tostring(data));
end
local_print(cstring .."}");
end

tableprint(data,cstring,0);
end

return M

你可以在luci目录下任何一个地方调用

local log = require "luci.log"
log.print("Hello World")
log.print_r({"Hello", "World"})

另外, log模块将输出信息到/tmp/luci.ouput下面, 我们可以用tail命令跟踪.

# tail -f /tmp/luci.output

于是通过这个小小的模块, 得以一窥这个openwrt上著名的程序. 确实很有趣, 有时间我会详细的把luci框架分析写下来.

另外luci程序自带了一个debug模块, 这是一个用来分析内存占用情况的模块, 你也可以在dispatcher.lua模块中开启.它的信息记录在/tmp/memtrace中.

参考

Luci实现框架
Luci tutorials
wifidog在OpenWrt路由器上添加LuCI的模块

转自https://forestgump.me/2015/03/28/luci-debug/