skynet inject address file.lua

inject d test/inject_fuck.lua　　-- d 是服务的 handle

拿 simpledb.lua 举例，修改如下

local skynet = require "skynet"
require "skynet.manager"    -- import skynet.register
local db = {}

local command = {}

local i = 13
local str = "abc"
local t = {}

function command.fuck()
    return i, str, t
end

skynet.info_func(function()
    return command.fuck()
end)

function command.GET(key)
    return db[key]
end

function command.SET(key, value)
    local last = db[key]
    db[key] = value
    return last
end

skynet.start(function()
    skynet.dispatch("lua", function(session, address, cmd, ...)
        local f = command[string.upper(cmd)]
        if f then
            skynet.ret(skynet.pack(f(...)))
        else
            error(string.format("Unknown command %s", tostring(cmd)))
        end
    end)
    skynet.register "SIMPLEDB"
end)

添加了 fuck 函数，并设置 info_func。

设置 info_func 主要用来在 debug console 中方便用 info d 来查看 inject 的结果

下面是 inject_fuck.lua

if not _P then
    print "inject error!"
    return
end

local function getuv(f) 
    local i = 1
    local ups = {}
    while true do
        local name, value = debug.getupvalue(f, i)
        if not name then
            break
        end
        ups[name] = { i, value }
        i = i + 1
    end
    return ups
end

local function uvjoin(f, old_f, old_uv)
    local i = 1
    while true do
        local name, value = debug.getupvalue(f, i)
        if not name then
            break
        end
        if old_uv[name] then
            debug.upvaluejoin(f, i, old_f, old_uv[name][1])
        end
        i = i + 1
    end
end


local command = _P.lua.command

local func = command.fuck
local old_uv = getuv(func)
for k,v in pairs(old_uv) do
    print(k,v[2])
end

print("  ---  ")

local t
local i
local str
function command.fuck()
    return str, t, i
end

uvjoin(command.fuck, func, old_uv)
-- debug.setupvalue( command.fuck, 1, 35 )

1. 取出原 fuck 函数的所有 upvalue

2. 然后关联到新的 fuck 函数

_P 内存的 key/value 其实就是 skynet.lua 里 14 行 proto 中的 name 和 dispatch 的 upvalue

local c = require "skynet.core"
local tostring = tostring
local tonumber = tonumber
local coroutine = coroutine
local assert = assert
local pairs = pairs
local pcall = pcall

local profile = require "profile"

local coroutine_resume = profile.resume
local coroutine_yield = profile.yield

local proto = {}
local skynet = {
    -- read skynet.h
    PTYPE_TEXT = 0,
    PTYPE_RESPONSE = 1,
    PTYPE_MULTICAST = 2,
    PTYPE_CLIENT = 3,
    PTYPE_SYSTEM = 4,
    PTYPE_HARBOR = 5,
    PTYPE_SOCKET = 6,
    PTYPE_ERROR = 7,
    PTYPE_QUEUE = 8,    -- used in deprecated mqueue, use skynet.queue instead
    PTYPE_DEBUG = 9,
    PTYPE_LUA = 10,
    PTYPE_SNAX = 11,
}

---

再看 simpledb.lua 的例子，文件中 disptch 的 upvalue 有两个，command 和 skynet

所以 _P.lua.command 就是文件中的 command，_P.lua.skynet 就是 skynet

在 debug console 用 inject 命令时要格外小心。。