Info

gdbserver9x is a very hacked together gdbserver implementation for debugging 32bits exes on old windows machines. It works best with BinaryNinja's GDP RSP adapter. Tested on Windows 98SE, Windows 2000-SP4 and Windows XP-SP3

Building

The tested toolchain is Microsoft Visual Studio 6.0 / Visual C++ 6.0 targeting 32-bit x86 Windows.

A helper script is available at build\build.cmd. Update TOOLCHAIN_DIR in that script to match your Visual Studio 6.0 installation, then run it from the build directory:

cd build
build.cmd

The script compiles the C sources and writes gdbserver9x.exe into build. If you use another compatible toolchain, compile the project as a Win32 console program and link against Winsock 2 (ws2_32.lib) plus the normal Win32 system libraries.

Usage

gdbserver9x.exe HOST:PORT PROGRAM [ARGS...]

Example:

gdbserver9x.exe 0.0.0.0:31337 C:\targets\hello.exe arg1 arg2

To enable verbose packet and debugger logging, set GDBLOG before launching:

set GDBLOG=1
gdbserver9x.exe 0.0.0.0:31337 C:\targets\hello.exe

set GDBRESTART=1

will restart the server on exit

Limitations

• Only 32-bit Windows debuggees are in scope.
• The server launches a new process; it does not attach to an existing process.
• While the debuggee is running, the main loop waits for the next Windows debug event and does not process arbitrary incoming RSP packets.
• Hardware breakpoints and watchpoints, are not currently implemented.

History

v1.0

• inital release not battle tested

v1.1

• allows round trip debugging via GDBRESTART var
• allows register writes
• allows memory writes

v1.2

• fix deadlock when reading module list on windows 2000

v1.3

• qGetTIBAddr,vFile and qXfer:libraries:read+ support for IDA 9.4

have fun
/yates.