WinDbg scripting extensions

Among many WinDbg scripting language flaws is a complete lack of advanced text searching/replacing functionality, especially associated with aliases. The library provides simple, "s" sed like command to search and replace regexp patterns in strings and WinDbg aliases. Together with WinDbg functionality of setting aliases to arbitrary WinDbg commands outputs, the library provides an effective tool to write advanced WinDbg scripts without a need to reach for Python substitutions.

Additionally the library supplies simple set of commands to open, read, write and close text/binary files. Of course this ain't shell nor Python but for simple scripts should be sufficient.

NOTE: Since my contact with Windows platform and the WinDbg debugger is currently rather occasional, the project is no more maintained. If someone is interested to continue work on it, feel free to contact me.

scriptext help command output

scriptext: Various scripting utilities

sxtr [-t num] input/pattern/replacement
    Look for a substring of the input string matching the extended POSIX RE pattern.
    If the pattern matches, the substring is extracted and modified according to
    the replacement string. The input string may contain alphanumeric characters
    plus '_' only, or must be enclosed in '' or "". If it's enclosed in [], then
    the input string specifies an alias name containing a string to process.
    Delimiter character is recognized as the first one after the input string. All
    the strings may contain escaped characters.
    -t: If specified, provides a pseudo-reg $t number where the matching result
        will be set: 0 - not matched, 1 - matched.

fopn [-m mode] [-t num] fname
    Open a file with a name fname.
    -m: Open mode (C standard). "r+" by default.
    -t: Pseudo-reg $t number where a handle of the opened file will be written. In
        case of opening error zero will be written there. If not specified $t0 is
        taken.
fwrt hndl input
    Write the input string to the file with the handle hndl. If the input string
    is enclosed in [] then it specifies an alias name containing a string to write.
    The input string may contain escaped characters.
frdl hndl
    Read line from a file with the handle hndl. The file shall be opened for read
    in the text mode.
fcls hndl
    Close a file with a handle hndl.

help
    Display this help.

Compiling and Installing

Prerequisites:

• MS SDK with cl, link and nmake; no need for MS Visual Studio,
• Debugging Tools for Windows with its SDK,

Compilation:

Set required building environment depending on your target platform (x86/x64/ia64, debug/release etc.) by calling MS SDK's SetEnv.Cmd script with proper arguments and make the library:

nmake

The result is scriptext.dll library located in the sources directory. Install it by:

nmake install

Loading and testing

I. Loading

0:000> .load scriptext

II. Help info

0:000> !scriptext.help

III. Text searching and replacement

Create test_alias alias, look for test string in it and replace by TEST. $t0 pseudo register is set to 1 (the searched string is found in the alias).

0:000> aS test_alias "Let's try test"

0:000> al
  Alias            Value
 -------          -------
 test_alias       Let's try test

0:000> !sxtr -t0 [test_alias]/(.*)test(.*)/\1TEST\2
Let's try TEST
0:000> r @$t0
$t0=0000000000000001

Look for test and TEST substrings in test_alias and set $t0 pseudo register as a result of searching. Searching is performed on the alias substitution.

0:000> !sxtr "-t0 \"${test_alias}\"/test"
0:000> r @$t0
$t0=0000000000000001

0:000> !sxtr "-t0 \"${test_alias}\"/TEST"
0:000> r @$t0
$t0=0000000000000000

IV. Simple grep

Create the following script with filename simple_grep:

!fopn -m "r" ${$arg1}
.if (@$t0!=0) {
  aS /c ${/v:ln} !frdl @$t0
  .while (1) {
    !sxtr -t1 [ln]/.+
    .if (@$t1!=0) {
      !sxtr -t1 [ln]/${$arg2}
      .if (@$t1!=0) {
        .echo ${ln}
      }
    } .else {
      .break
    }
    aS /c ${/v:ln} !frdl @$t0
  }
  !fcls @$t0
  ad /q ${/v:ln}
}

and execute it with 2 arguments: input file and searched RE pattern:

0:000> $$>a< simple_grep file pattern

License

GNU GENERAL PUBLIC LICENSE v2. See LICENSE file for details.