How to attach DynamoRIO to a running program

[gx Lin]

Hello,

I'm trying to attach DynamoRIO to a running program, could you please give me some help?

I implemented a tool to detect memory access based on DynamoRIO, and successfully run with the following command:

drrun -t my_tool -- program_name

But now, I have to apply this tool to a running program.I need to attach and detach my tools to the target program while it is running.  I cannot modify the target program's source code. Is there any way to attach my tool to it?

I found 3 ways but they all have some problems：

1. run it with: drrun -attach program_pid，but I get: ERROR: attaching to running processes is not yet implemented

2. Internally-triggered attach through dr_app_start()：but according to my understanding, this method needs to modify the source code of the target program

3. ptrace: I found some information related to ptrace. I am not sure if this function is complete now. If it has been implemented, could you please give me some guidance on how to use ptrace？

Is there any other way I missed？

Thanks for your help !

Best regards,

Bess Lin

[Derek Bruening]

Externally attaching to an unmodified program was never fully finished off (it was never part of the use case of the main developers); application-triggered attach is used quite a bit though, so the main internal infrastructure for attaching and detaching is already there.  There is a PR that adds the few missing pieces at https://github.com/DynamoRIO/dynamorio/pull/3328 you could try; looks like the original author has not had time to finish it and it is just waiting for a new developer (you?) to finalize it and get it merged.

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[gx Lin]

Thank you very much for your reply. I still have some questions. What does "application-triggered attach" exactly mean? Do I need to modify the source code of the target application? How can I control the time of attach and detach? Or I can only determine when to attach by modifying the application source code?

Thanks for your help !  

[Derek Bruening]

Yes, modifying the source.  See https://dynamorio.org/dynamorio_docs/API_BT.html#sec_startstop, https://dynamorio.org/dynamorio_docs/dr__app_8h.html#abcdedd068a4d264401c31767355ec218.

To view this discussion on the web visit https://groups.google.com/d/msgid/dynamorio-users/4488631c-5ae1-436e-a238-c708387b1c20n%40googlegroups.com.