Process Tracing Tips and Tools

Single Process Tracing

• Shell interpreter tracing with set -x aka set -o xtrace

  • Example from Andy: I used this to discover that autotool configure scripts call rm and cat commonly, and then we implemented builtin rm and builtin cat

• strace myprog

  • the -e flag filters by syscall
  • the -c flag creates a histogram of syscalls
  • Samuel used this for the $PWD bug

• ltrace myprog

  • has an -e flag
  • Example from Andy: I used this to debug setlocale() calls in bash versus OSH

Multi Process Tracing

• shell tracing with set -x; export SHELLOPTS - bash and OSH have a feature where you can export SHELLOPTS to make all processes trace

• strace -ff -o prefix - follow forks, creates prefix.$PID files

Related

Process Tracing Projects