IDA DOSBox debugger plugin

Authors

• Eric Fry efry@users.sourceforge.net
• Willem Jan Palenstijn wjp@usecode.org

Getting started

1. Download the IDA SDK.
2. Download the plugin source from https://github.com/wjp/idados.
3. Download the patched DOSBox source from the 'idados' branch of https://github.com/wjp/dosbox.
4. Build the plugin and DOSBox as described in the BUILD.md file.

Usage

1. Load the executable you are debugging into IDA in the usual manner.
2. Configure DOSBox with core=normal.
3. Run DOSBox and mount disks, etc. in the usual manner.
4. In DOSBox, run the binary you want to debug, prefixed with debug. e.g. debug sierra.exe. DOSBox will pause here while waiting for a connection from IDA.
5. In IDA, start the debugger, selecting the "Remote DOSBox" debugger. You should be able to leave the connection options at their defaults. The binary and arguments are ignored.

Notes

This plugin has not been tested on many platforms, but it has been reported to work with 32-bit IDA 6.9 Starter, on 32-bit Windows (using MSYS2), 64-bit Linux, and 64-bit Mac OS X.

The debugger plugin will rebase the program to match the memory location in DOSBox, but there have been many bugs with this in older versions of IDA. If this is causing problems, try manually rebasing before starting the debugger, or even recreating the database at the right offset.

There is a known bug with breakpoints on the program entry point. As a workaround, you can use the "Suspend on debugging start" option in IDA if you wish to break on starting the process. Breakpoints at other locations should work fine.

With a 32-bit IDA, you will have to build a 32-bit dosbox, even on 64-bit platforms.

And finally, patches to improve the plugin are most welcome!