I feel stupid, because I didn't know strace can do this, I did it once with a gdb script:
https://gist.github.com/hadrianw/5b8d33a4b353c49e7dbd6eb55f8...
My learning: RTFM.
https://gist.github.com/hadrianw/5b8d33a4b353c49e7dbd6eb55f8...
My learning: RTFM.