From: Guillaume Marcais <guslist@...>
Date: 2004-12-01T01:52:24+09:00
Subject: Windows SendMessage

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Has anyone ever tried to send messages between applications using the
Windows messaging system (SendMessage call). Given my little knowledge
of Windows, I started with Ruby and Win32API (hopefully it is achievable
that way).

I am trying to discuss with the pageant program from PuTTy to get the
keys. I recompiled pageant with debugging enable so I can see the
request coming in. It works with PuTTy. But with my Ruby app mimicking
what PuTTy does to get the keys, it seems that pageant doesn't even get
the message.

The code is given in the attachement.The stuff about the file mapping
can be ignored. The SendMessage call returns 0 and pageant doesn't
display any debugging information, as if no message whatsoever was ever
received.

Is there any initialization to be done for Windows to agree to dispatch
my message? 

Thanks for your help,
Guillaume.


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#! /usr/bin/ruby

require 'Win32API'

module Pageant
  # From Putty pageant.c
  AGENT_MAX_MSGLEN =3D 8192
  AGENT_COPYDATA_ID =3D 0x804e50ba
 =20
  # From Putty ssh.h
  SSH_AGENT_FAILURE =3D 5
  SSH_AGENT_SUCCESS =3D 6
  SSH2_AGENTC_REQUEST_IDENTITIES =3D 11
  SSH2_AGENT_IDENTITIES_ANSWER =3D 12
  SSH2_AGENTC_SIGN_REQUEST =3D 13
  SSH2_AGENT_SIGN_RESPONSE =3D 14
  SSH2_AGENTC_ADD_IDENTITY =3D 17
  SSH2_AGENTC_REMOVE_IDENTITY =3D 18
  SSH2_AGENTC_REMOVE_ALL_IDENTITIES =3D 19

  module Win
    # From winbase.h, winnt.h
    INVALID_HANDLE_VALUE =3D -1
    NULL =3D nil
    PAGE_NOACCESS =3D 0x0001
    PAGE_READONLY =3D 0x0002
    PAGE_READWRITE =3D 0x0004
    PAGE_WRITECOPY =3D 0x0008
    PAGE_EXECUTE =3D 0x0010
    PAGE_EXECUTE_READ =3D 0x0020
    PAGE_EXECUTE_READWRITE =3D 0x0040
    PAGE_EXECUTE_WRITECOPY =3D 0x0080
    PAGE_GUARD =3D 0x0100
    PAGE_NOCACHE =3D 0x0200
    FILE_MAP_ALL_ACCESS =3D 0xf001f
    FILE_MAP_READ =3D 4
    FILE_MAP_WRITE =3D 2
    FILE_MAP_COPY =3D 1
    WM_COPYDATA =3D 74

#     CreateWindow =3D Win32API.new('user32', 'CreateWindow',
#                                 ["P", "P", "L", "L", "L", "L", "L",
#                                   "L", "L", "L", "P"], "L")
    FindWindow =3D Win32API.new('user32', 'FindWindow', ["P", "P"], "L")
    GetCurrentThreadId =3D Win32API.new('kernel32', 'GetCurrentThreadId',=20
                                      [], "L")
    CreateFileMapping =3D Win32API.new('kernel32', 'CreateFileMapping',=20
                                     ["L", "P", "L", "L", "L", "P"], "L")
    MapViewOfFile =3D Win32API.new('kernel32', 'MapViewOfFile',
                                 ["L", "L", "L", "L", "L"], "P")
    UnmapViewOfFile =3D Win32API.new('kernel32', 'UnmapViewOfFile',
                                   ["P"], "V")
    CloseHandle =3D Win32API.new('kernel32', 'CloseHandle', ["L"], "V")
    SendMessage =3D Win32API.new('user32', 'SendMessage',=20
                               ["L", "L", "P", "P"], "L")
  end

  class Pageant
    def initialize
      @win =3D Win::FindWindow.call("Pageant", "Pageant")
      raise "Pageant not started" if @win =3D=3D 0
    end
   =20
    def send_query(query)
      res =3D nil
      mapname =3D "PageantRequest%08x\000" % Win::GetCurrentThreadId.call()
      # p mapname
      filemap =3D Win::CreateFileMapping.call(Win::INVALID_HANDLE_VALUE,=20
                                            Win::NULL,
                                            Win::PAGE_READWRITE, 0,=20
                                            AGENT_MAX_MSGLEN, mapname)
      raise "Creation of file mapping failed" if filemap =3D=3D 0
      ptr =3D Win::MapViewOfFile.call(filemap, Win::FILE_MAP_WRITE, 0, 0,=20
                                    AGENT_MAX_MSGLEN)
      cds =3D [AGENT_COPYDATA_ID, mapname.size, mapname].pack("NNp")
      p [cds].pack("p").unpack("L")[0]
      p @win
      id =3D Win::SendMessage.call(@win, Win::WM_COPYDATA, Win::NULL, cds)
      p id
      if id > 0
        retlen =3D 4 + ptr.unpack("N")
        p retlen
        res =3D ptr.unpack("p#{retlen}")
      end       =20
      Win::UnmapViewOfFile.call(ptr)
      Win::CloseHandle.call(filemap)
      res
    end

    def request_identities
      request =3D [1, SSH2_AGENTC_REQUEST_IDENTITIES].pack("Nc")
      # p request
      res =3D send_query(request)
      res
    end
  end
end

pageant =3D Pageant::Pageant.new
$stdout.puts("Requesting identities")
ids =3D pageant.request_identities
$stdout.puts("Press Enter to end")
$stdin.gets

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