Record, for each process ID:
- The timestamp of the fork() which creates it and the parent process ID,
- The path passed to execve(), if any,
- The first path resolved by namei, if any, and
- The timestamp of the exit() which terminates the process.
Allow this information to be dumped via a new sysctl, debug.tslog_user.
Note that recording namei is needed in order to obtain the names of rc.d scripts
being launched, as the rc system sources them in a subshell rather than execing
With this commit it is now possible to generate flamecharts of the entire boot
process from the start of the loader to the end of /etc/rc.