`rd` The Record & Debug Tool

rd is a Rust language port of the mozilla/rr debugger.

The port is in progress but many things work already (see below).

Installing

rd requires a nightly version of the rust x86_64-unknown-linux-gnu toolchain to compile.

git clone git@github.com:sidkshatriya/rd.git
cd rd
cargo install --locked --force --path .

Alternatively, use --debug like below. Things will run much more slowly as the code will be compiled with lower compiler optimizations, extra debug-mode assertions etc.

cargo install --debug --locked --force --path .

In general, run in release mode as the debug mode can be much slower. Run rd in debug mode if you run into issues or are working on developing rd.

The program has been tested to compile and run properly on a 64-bit Ubuntu 20.04 installation at the moment only.

Please file a ticket if rd does not work properly for your specific Linux distribution. In general, if rr compiles and runs properly in your Linux distro, rd should do the same.

Running `rd`

Invoking rd without any parameters will give you help.

$ rd

To get help on specific rd sub-command:

$ rd rerun --help

Credits

The rd project would not have been possible without the work done in the mozilla/rr project. Many human-years of development effort have gone into making rr the truly amazing piece of software that it is.

The rd project is grateful to all the contributors of the mozilla/rr project.

Background

rd works on the same principles as rr. Please see mozilla/rr where you will find further information. More specifically, an excellent technical overview of rr can be found at arXiv:1705.05937.

Contributions

Contributions to the Record and Debug Tool (rd) are welcome and encouraged!

By contributing to rd you agree to license your contributions under the MIT license without any further terms and conditions.

What works

The port is currently in progress and not ready for end-user usage. However developers interested in contributing to this project will find there is a lot to work with and build upon. The project already contains 30k+ lines of ported over Rust code.

The port is currently capable of only replaying traces recorded previously by mozilla/rr. rd is not yet capable of recording traces of its own but this will come in the future as the port progresses.

The following work:

rd rerun
rd replay -a
- This means that interactive replay (which uses a debugger like gdb) is not yet supported
rd buildid
rd cpufeatures
rd dump
rd traceinfo

Tips and Suggestions

Add an alias

After installing rd add an alias like this in your bash (or other shell):

Assuming you have a local source build of mozilla/rr at /home/abcxyz/rr/build

alias rd="rd --resource-path=/home/abcxyz/rr/build

This will avoid constantly specifying the resource path on every rd invocation.

Logging

The various logging levels are debug, info, warn, info and fatal. To log at warn by default and debug for all messages from the auto_remote_syscalls rust module (as an example) do:

$ RD_LOG=all:warn,auto_remote_syscalls:debug rd <etc params>

Recording traces

rd cannot record its own traces at this point in time. It can, however, process traces previously recorded by rr. Make sure these traces are recorded with the -n flag (disabled syscallbuf). rd will support syscallbuf recordings in the future.

rr record -n <program to be recorded>

_RR_TRACE environment variable

rd understands the _RR_TRACE environment variable. E.g.

$ _RR_TRACE=/the/trace/directory rd replay -a

jabedude/rd

rd The Record & Debug Tool