thorin -- the DWARF debugger

thorin is a simple debugger for linux and MacOS, like gdb's (very) little brother. It currently only works on C programs and x86_64 architectures.

thorin is still in development -- see the TODO section.

Installation

Get Rust and

cargo install thorin

Usage

thorin <target-program>

thorin will start the target program and wait for an exception, like a segfault.

If the program exits successfully, nothing happens.

If the program triggers an exception, thorin will suspend it and capture its state. You can inspect the program's state through the thorin console:

thorin> help
Commands:
  (print|show|get) <variable-name>:  Print the value of a variable.
  read <address> <count> <type>:     Read the value at <address>. <type>
                                     is the type of the value, <count> is the
                                     number of values to read.
  help:                              Print this help message.
  (exit|quit):                       Quit thorin.

In order to access variables and other source-level information, thorin needs to be able to read debugging information in the program's object file. To provide this information, all you need to do is compile your C programs with the -g flag.

cc -g [other flags] myprogram.c

As of now, you will probably have to invoke thorin as root on MacOS. I will eventually figure out how to get code-signing to work with Rust binaries.

Why does this exist?

There is no real reason to use thorin over gdb, lldb or other similar more powerful debuggers. I wrote this because

1. I wanted to learn Rust.
2. It was a fun exercise in system programming.

I chose the name 'thorin' because this program reads DWARF files (the predominant format for debugging information).

TODO

• fix the CLI
• passing arguments to and changing stdin/stdout of target process
• general bugfixes and QOL improvements
• MacOS code-signing stuff

Author(s)

• Ajay Tatachar (ajaymt2@illinois.edu)