Re: Proxy DLL for Lua 5.1; can't get it to work with statically linked liblua

[Ulrich Schmidt <u.sch.zw@...>]

Why not change the Value of local var reallib in mkforwardlib.lua?
Let it point to your exe, before you call the link command in 
mkforwardlib.lua
This way the proxy-dll will point to your .exe.

I modified mkforwardlib.lua for my scenario. and attached it to this 
mail. You need to call it inside a Widows SDK command window. It uses 
dumpbin.exe to read the exports from <param1> and writes <param2>.dll 
and <param2>.lib using lib.exe.


Ulrich.

Am 27.11.2013 06:03, schrieb Paul K:
> Hi Jerome,
>
> > Did you try http://lua-users.org/wiki/LuaProxyDllThree ? The main
> > advantage is that it produces a DLL with no code, only metadata for
> > the Windows DLL loader, so there is less chance of a crash. Also it
> > produces a very tiny file, if size matters to you.
>
> Yes, I'm familiar with ProxyDllThree as I'm using it to support LfW
> modules that depend on Lua5.1.dll (which proxies requests to my
> Lua51.dll). In this case I need to proxy the requests to a statically
> compiled lua.exe and it seems like this method only proxies calls to a
> dll.
>
> Paul.

--
Ulrich Schmidt, 08060 Zwickau, Werdauer Str. 90
Tel.: +49 (172) 7928 968

local util = require "util"

local reallib
local fakelib
local machine

local errmsg
if arg[1] then reallib = arg[1] end
if arg[2] then fakelib = arg[2] end
if arg[3] then machine = arg[3] else machine = "X86" end

if #arg<2 then
	errmsg = "not enough parameters"
elseif not ({X86=true, AMD64=true, IA64=true})[machine] then
	errmsg = "'"..machine.."' is not a recognized machine architecture"
end
if errmsg then
	if errmsg then io.stderr:write("Error: "..errmsg.."\n") end
	io.stderr:write[[
Usage: mkproxy <reallib> <fakelib> [<machine>]

    reallib         The name of the existing dll that you want to use.
    fakelib         The name of the fake dll that you want to create and that
                    will call the reallib instead.
    machine         The hardware architecture of your windows version among:
                    X86, AMD64, IA64
                    default: X86

  Example: mkforwardlib lua51.dll lua5.1.dll X86
]]
	os.exit(0)
end

local function readsyms()
  local syms = {}
  local f = assert(io.popen('dumpbin /exports '..arg[1]))
  local s
  s = f:read()
  while s do
    if s:find("    ordinal hint RVA      name") == 1 then
      assert(f:read() == "")
      for s in f:lines() do
        if s == "" then 
          f:close(f)
          return syms 
        end
        local sym = s:match("%s+%d+%s+%x+%s+%x+%s+([^%s]+)")
        if sym then
          table.insert(syms, sym)
        end
      end
    end
    s = f:read()
  end
  close(f)
  return nil
end

local command = {
	"link.exe -dll -nologo -noentry -machine:" .. machine .. " -incremental:no -nodefaultlib \z
  -out:"..fakelib..".dll -implib:"..fakelib..".lib",
}

local symbols = readsyms()

for _,symbol in ipairs(symbols) do
	table.insert(command," /export:"..symbol.."="..reallib.."."..symbol)
end

print('"'..table.concat(command)..'"')
os.execute('"'..table.concat(command)..'"')