StringReplace() does not work on binary data

[AndyS01]

I'm trying to replace all occurrences of one string in a binary file with another string (e.g. all "C:\" with "D:\"), but StringReplace() does nothing.

I opened my files in Binary mode and set the data read in to binary(), but nothing works.

My test script reads a compiled version of the script, does the replacements, then writes the results to an output file.

Prior to calling StringReplace(), I call StringInStr() to see if my 'from' string is found. The StringInStr() reports that it found the string, but the StringReplace() reports 0 replacements. Just to be sure, I did a binary compare (BeyondCompare) and the input and output files were exactly the same.

Here is my test code:

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#AutoIt3Wrapper_UseUpx=n
#AutoIt3Wrapper_Au3Check_Parameters=-d -w 1 -w 2 -w 3 -w 4 -w 5 -w 6
Opt('MustDeclareVars', 1)

_Main()

Func _Main()
Local $infn, $infh, $outfn, $outfh, $cnt, $str_from, $str_to
Local $buffer, $offset = 0, $bufsize, $mcnt, $matches = 0, $ret

$infn = StringTrimRight(@ScriptName, 4) & ".exe"
$outfn = "test2_out.exe"

$infh = FileOpen($infn, 16 + 0)
If ($infh <= 0) Then Exit (1)

$outfh = FileOpen($outfn, 16 + 2) ; 2 = Write mode (erase previous contents)
If ($infh <= 0) Then Exit (1)

$str_from = "D:\"
$str_to = "C:\"
$bufsize = 2000

While (1)
FileSetPos($infh, $offset, 0)

$buffer = FileRead($infh, $bufsize)
If (@error == -1) Then ExitLoop
$cnt = @extended

$buffer = Binary($buffer)

$ret = StringInStr($buffer, $str_from)
If ($ret >= 0) Then ConsoleWrite("+++: 1 or more strings are in the buffer" & @CRLF)

$buffer = StringReplace( _
$buffer, _
$str_from, _
$str_to _
)

$mcnt = @extended
$matches += $mcnt
ConsoleWrite("+++: " & $mcnt & " replacement(s) made" & @CRLF)

FileWrite($outfh, $buffer)

$offset += $cnt
WEnd

FileClose($infh)
FileClose($outfh)

ConsoleWrite("+++: matches: " & $matches & @CRLF)
ConsoleWrite("+++: processed " & $offset & " bytes." & @CRLF)
EndFunc ;==>_Main

[BrewManNH]

You're opening the file in binary mode, then converting what you read from the file to binary, then you're looking for an ASCII string in it, you might want to rething what you're looking for and what the contents of $buffer actually looks like.

[Melba23]

AndyS01,

As I read that code, you trying to use this to rewrite a compiled AutoIt file:

$infn = StringTrimRight(@ScriptName, 4) & ".exe" ; Remove .au3/.exe and replace it with .exe
$outfn = "test2_out.exe"

$infh = FileOpen($infn, 16 + 0) ; Open the .exe file

If that is indeed the case then you need to know that the script part of the compiled .exe is compressed before being added to the interpreter stub and so is very unlikely to hold the literal strings you seem to want to replace:

$str_from = "D:"
$str_to = "C:"

even if you use the correct format for the strings as BrewManNH has suggested. So I am not at all sure that you will ever succeed.

What I have done in the past as a coding exercise was to store the basic text script in the resources of the compiled exe (using #AutoIt3Wrapper_Res_SaveSource) and then when needed extract it, modify it and then recompile the whole thing. But you are now into FileInstalling Aut2Exe and AutoItSC.bin which seriously increases the size of the compiled file. Are you sure that you want to go to so much trouble?

M23

[guinness]

Just a note, if you do decide to use #AutoIt3Wrapper_Res_SaveSource (as Melba23 suggest,) then look at _GetSavedSource in my signature.

[AndyS01]

Thank you for your suggestions. You're right, a compiled AutoIT file will not have what I want. However, making the compiled script an input file was just a test.

What I'm going to use my script for, is to replace "C:" with "D:" in a very large binary file. I will actually be editing it 'in place'.

I used a 'strings' utility on several .exe files until I found relatively small one with an instance of "D:". I used a copy of "C:WindowsSystem32poqexec.exe" as a test file. This file has 1 occurrence of "D:" (at offset 0x0950).

StringReplace() still didn't do any substitutions.

I'n not sure what 'binary()' buys me. Perhaps I should to a StringReplace() using patterns enclosed with 'binary()'.

[AndyS01]

Well, after much experientation, I got a lot farther. I found that mixing Binary...() functions and String...() functions doesn't really work.

My new code, below, successfully finds all occurrences of '$str_from'. However, I cannot figure out how to replace binary($buffer) data with new data ($str_to).

I would want to say "BinaryMid($buffer, $x1, 3) = StringToBinary($str_to)", but apparently "BinaryMid($buffer, $x1, 3)" cannot be on the left side of an assignment (I get syntax errors when I try to run with this line in).

How can I replace data in a binary($buffer)?

expandcollapse popup

#AutoIt3Wrapper_UseUpx=n
#AutoIt3Wrapper_Au3Check_Parameters=-d -w 1 -w 2 -w 3 -w 4 -w 5 -w 6
Opt('MustDeclareVars', 1)

_Main()

Func _Main()
   Local $infn, $infh, $outfn, $outfh, $cnt, $str_from, $str_to, $x1
   Local $buffer, $offset = 0, $bufsize, $matches = 0

   $infn = "poqexec.exe"
   $outfn = "test2_out.exe"

   $infh = FileOpen($infn, 16 + 0)
   If ($infh <= 0) Then Exit (1)

   $outfh = FileOpen($outfn, 16 + 2) ; 2 = Write mode (erase previous contents)
   If ($infh <= 0) Then Exit (1)

   $str_from = "D:"
   $str_to = "C:"
   $bufsize = 0x1000

   While (1)
      FileSetPos($infh, $offset, 0)

      $buffer = FileRead($infh, $bufsize)
      If (@error == -1) Then ExitLoop
      $cnt = @extended
      $buffer = Binary($buffer)

      For $x1 = 0 To $cnt - 3
         If (BinaryToString(BinaryMid($buffer, $x1, 3), 1) = $str_from) Then
            ConsoleWrite("+++: found it at 0x" & Hex($offset + $x1) & @CRLF)
            $matches += 1
            ; The next line replaces the 'found' data with the 'repace with' data
            ;BinaryMid($buffer, $x1, 1) = StringToBinary($str_to)
         EndIf
      Next

      FileWrite($outfh, $buffer)
      $offset += $cnt
   WEnd

   FileClose($infh)
   FileClose($outfh)

   ConsoleWrite("+++: matches:  " & $matches & @CRLF)
   ConsoleWrite("+++: processed " & $offset & " bytes." & @CRLF)
EndFunc   ;==>_Main

[AZJIO]

Look

If the binary data, the lines must also be hexadecimal numbers. You can replace the text in the EXE-file, as if it were a string. I replaced and comparing the result was correct.

screenshot (Change in binary data)

Edited October 6, 2012 by AZJIO

[DrLarch]

Look

If the binary data, the lines must also be hexadecimal numbers. You can replace the text in the EXE-file, as if it were a string. I replaced and comparing the result was correct.

screenshot (Change in binary data)

AZJIO - your utility works great, but I need to be able to modify a binary file from within my script. I dug through your code, but it's obviously beyond me . I can easily read in a binary file to a variable and dump it back out to another file:

$hFile = FileOpen(@ScriptDir & "binaryfile1.tmp", 16)
$hFileContents = FileRead($hFile)
FileClose($hFile)

$nFile = FileOpen(@ScriptDir & "binaryfile2.tmp", 17)
FileWrite($nFile, $hFileContents)
FileClose($nFile)

... but how to replace/insert data within $hFileContents?! Could one split the binary data at the position to edit (into "before" & "after" variables), convert the replace/insert data (with _StringToHex) and then:

FileWrite($nFile, $hFileContentsBefore & $EditData & $hFileContentsAfter)

?? I apologize, I'm clueless on dealing with binary data - can anyone provide an example?

[DrLarch]

Never mind, I think I figured it out:

#include 
#include 
$Insert = "Blahblahblah"
$InsertHex = _StringToHex($Insert)

$nFile = FileOpen(@ScriptDir & "test.bin", 18)
FileWrite($nFile, "0x0B00000000" & $InsertHex & "000D0A000000")
FileClose($nFile)

I didn't understand the hex format and how AutoIt handles binary data. Now I know a little bit more via trial and error.