From: "李晶" <thyrlian@...>
Date: 2010-07-27T16:51:11+09:00
Subject: Re: Help: How to pass a struct as a pointer to Win32API?

--001636c5b77ba3dcad048c59c33c
Content-Type: text/plain; charset=UTF-8

Hi Park,

Thanks for your answer, and I've tried your code, everything is fine but
nothing is retrieved for item or subitem.

So the result will be like this:
 -
 -
 -
which should be "#{item} - #{subitem}"

Could you plz tell me what's wrong?  Meanwhile I will investigate on this.

BTW, does it matter if I remove VirtualAllocEx and WriteProcessMemory part?
Since I mentioned it's not a pop-up.

Thanks a lot.

Regards,
Jing Li


2010/7/27 Heesob Park <phasis@gmail.com>

> Hi,
>
> 2010/7/27 Jing Li <thyrlian@gmail.com>:
> >  Hi all,
> >
> > As titled, I want to read text content from a standard syslistview32
> control
> > in an application.  And the syslistview32 control is not a pop-up but
> > embedded in the application, which means the control has same process ID
> as
> > the application.  In that case, I don't have to call VirtualAllocEx or
> > WriteProcessMemory.
> >
> > So far, I could successfully get syslistview32 control's handle, count
> how
> > many items listed.  But still can not read its content.  Could you please
> > tell me how to do it correctly?
> >
> > require 'Win32API'
> > findwin = Win32API.new('user32', 'FindWindow', 'PP', 'L')
> > getdlg = Win32API.new('user32', 'GetDlgItem', 'LL', 'L')
> > sendmsg = Win32API.new('user32', 'SendMessage', 'LLLP', 'L')
> >
> > #Some irrelevant details are ignored
> > #Here I've already got syslistview32 control's handle, let's assume it is
> > resultslist = 3739380
> >
> > puts "Count of items = #{sendmsg.call(resultslist, 4100, 0, nil)}"
> > #LVM_GETITEMCOUNT = 0x1004
> > puts header = getdlg.call(resultslist, 0).to_s(16).upcase
> > #No problem, this works
> >
> > #From here I tried to SendMessage with LVM_GETITEMTEXT parameter to get
> > syslistview32's content
> > #Solution I: define a struct as described in MSDN, but something wrong
> when
> > I tried to pack, this is due to my lack of knowledge on pack&unpack
> > LV_item = Struct.new(:mask, :iItem, :iSubItem, :state, :stateMask,
> :pszText,
> > :cchTextMax, :iImage, :lParam)
> > lv_item = LV_item.new()
> > puts sendmsg.call(resultslist, 4165, 1, lv_item.to_a.pack("p"))
> >    => return value is 1, success?
> > puts lv_item.inspect
> >    => #<struct LV_item mask=nil, iItem=nil, iSubItem=nil, state=nil,
> > stateMask=nil, pszText=nil, cchTextMax=nil, iImage=nil, lParam=nil>
> > absolutely not succeed
> > #If I initiate lv_item = LV_item.new(0, 0, 0, 0, 0, "", 0, 0, ""), then
> > error occurs at packing: can't convert Fixnum into String (TypeError).
>  Can
> > I pack integer pointer except pack("p")?
> >
> > #Solution II: Directly pack an array and pass to SendMessage, return
> value
> > is still nil
> > lv_item = [0, 0, 0, 0, 0, "\000", 0, 0, "\000"]
> > lv_item = lv_item.pack("IiiIIpiip")
> > puts sendmsg.call(resultslist, 4165, 1, lv_item)
> >    => return value is 1, success?
> > lv_item = lv_item.unpack("IiiIIpiip")
> > puts lv_item.inspect
> >    => [0, 0, 0, 0, 0, "\000", 0, 0, "\000"], nothing is padded actually
> >
> > I really appreciate if you can answer my question, thanks in advance.
> >
> Here is a code using VirtualAllocEx and WriteProcessMemory for a
> general purpose.
>
>
> require 'Win32API'
>
> findwin = Win32API.new('user32', 'FindWindow', 'PP', 'L')
> getdlg = Win32API.new('user32', 'GetDlgItem', 'LL', 'L')
> sendmsg = Win32API.new('user32', 'SendMessage', 'LLLP', 'L')
>
> getWindowThreadProcessId = Win32API.new('user32',
> 'GetWindowThreadProcessId', 'LP', 'L')
> openProcess = Win32API.new('kernel32', 'OpenProcess', 'LIL', 'L')
> virtualAllocEx = Win32API.new('kernel32', 'VirtualAllocEx', 'LPLLL', 'L')
> virtualFreeEx = Win32API.new('kernel32', 'VirtualFreeEx', 'LLLL', 'L')
> writeProcessMemory = Win32API.new('kernel32', 'WriteProcessMemory',
> 'LLPLP', 'I')
> readProcessMemory = Win32API.new('kernel32', 'ReadProcessMemory', 'LLPLP',
> 'I')
>
> PROCESS_VM_OPERATION = 0x08
> PROCESS_VM_READ = 0x10
> PROCESS_VM_WRITE = 0x20
> PROCESS_QUERY_INFORMATION = 0x400
> MEM_COMMIT = 0x1000
> MEM_RELEASE = 0x8000
> PAGE_READWRITE = 0x04
> LVM_GETITEMTEXT = 0x1000+45
> LVM_GETITEMCOUNT = 0x1000+4
> SIZE_OF_LVITEM = 60
>
> resultslist = 0xB0044   ##<== start with some given handle
>
> count = sendmsg.call(resultslist,LVM_GETITEMCOUNT, 0, nil)
> lv_item = [0, 0, 0, 0, 0, nil, 512, 0, 0,0,0,0,0,0,0]
> lv_item = lv_item.pack("LiiLLpiiLiiLLLL")
> pid = 0.chr*4
> getWindowThreadProcessId.call(resultslist, pid)
> pid = pid.unpack('L').first
> process =
> openProcess.call(PROCESS_VM_OPERATION|PROCESS_VM_READ|PROCESS_VM_WRITE|PROCESS_QUERY_INFORMATION,0,pid)
> _lvi=virtualAllocEx.call(process, nil, SIZE_OF_LVITEM,MEM_COMMIT,
> PAGE_READWRITE)
> _item=virtualAllocEx.call(process, nil, 512, MEM_COMMIT,PAGE_READWRITE)
> _subitem=virtualAllocEx.call(process, nil, 512, MEM_COMMIT,PAGE_READWRITE)
>
> for i in 0..count
>  lv_item[8,4] = [0].pack('L')
>  item = 0.chr * 512
>  lv_item[20,4] = [_item].pack('L')
>  writeProcessMemory.call(process, _lvi, lv_item, SIZE_OF_LVITEM, nil)
>  sendmsg.call(resultslist, LVM_GETITEMTEXT, i, _lvi)
>
>  subitem = 0.chr * 512
>  lv_item[8,4] = [1].pack('L')
>  lv_item[20,4] = [_subitem].pack('L')
>  writeProcessMemory.call(process, _lvi, lv_item, SIZE_OF_LVITEM, nil)
>  sendmsg.call(resultslist, LVM_GETITEMTEXT, i, _lvi)
>
>  readProcessMemory.call(process, _item, item, 512, nil)
>  readProcessMemory.call(process, _item, subitem, 512, nil)
>  item = item.strip!
>  subitem = subitem.strip!
>  puts "#{item} - #{subitem}"
> end
>
> virtualFreeEx.call(process, _lvi, 0, MEM_RELEASE)
> virtualFreeEx.call(process, _item, 0, MEM_RELEASE)
> virtualFreeEx.call(process, _subitem, 0, MEM_RELEASE)
>
>
>
> Regards,
> Park Heesob
>
>

--001636c5b77ba3dcad048c59c33c--