yijiem / tracing

tracing

Issues:

1. Due to bpftrace/bpftrace#246, if the tracee exits first then the stacktrace would not be symbolicated by bpftrace.

   Current plan is to use an offline approach:

   • print the /proc/self/maps as provided by util.h at the start of the tracee program
   • calculate the relative file offset of the instruction by doing <instruction address> - <module load address>
   • use something like addr2line -a -e <binary> -f -C <offset> to translate the offset into function name, file and line number.

   symbolizer.py has basic support for this, it still has some issues though.