Extend \dt* to allow file redirection

[hexploitable]

Trace output can be extensive, it would be nice to have a way to have trace output written to a file.
SInce trace output is async, we cannot directly parse the output with r2's json capabilities.

Should be easy to add, just capturing it here so the thought is not lost.

[oleavr]

Another option would be to capture outputs in one or more variables, to allow processing within r2. The drawback would obviously be memory usage and needing a configurable limit to specify when to start dropping old data.

[hexploitable]

Yeh, discussed offline with @mrmacete, could be an idea to cache it in the agentside and have a \dts command or similar to get a summary of events. And yeah I think we'd want some variables to configure parameters including event count, data size, etc.

[hexploitable]

Actually looking at the source there is already:
https://github.com/nowsecure/r2frida/blob/master/src/agent/index.js#L2661-L2679

It's just invoked. It looks like we can just replace traceLog() calls with traceEmit().

[hexploitable]

Converted the traceLog calls to traceEmit() locally and this works nicely.

Thoughts?

/cc @enovella @mrmacete @radare

[hexploitable]

Perhaps we can a) convert the traceLog calls to traceEmit and b) define and utilize new variables for memory limits.

[enovella]

Hi guys,

both options are a great option. I personally liked more the way that \dtf was displaying the traces. The new way is to bulky and it is tough to read. Too much info! We could also have extensive and light code tracing as well.

@hexploitable Can you open a PR to test?

[hexploitable]

Yeah I'll open something WIP to get the ball rolling but at a glance, we can switch to using the emit functions, and then introduce variables for limits and json|simple logs.

[trufae]

+1

[hexploitable]

Updated the PR with the changes. A hook.output config value can now be set to json (default is simple), to allow more or less information as you wish.

Since the traces now use traceEmit(), these will be written to file instead of stdout, if you have set file.log to a filepath like so:

\e file.log=example_trace.log