TODO

• fill How Descriptor Numbers Are Chosen in File Descriptors: Basics

• signals / async

  • traditional/async delivery (-> on return from syscall)

  • when called:

    • man -s 2 sigreturn

      “If the Linux kernel determines that an unblocked signal is pending for a process, then, at the next transition back to user mode in that process (e.g., upon return from a system call or when the process is rescheduled onto the CPU), it creates a new frame on the user-space stack”

• events

  • link from Introduction signalfd

  • link from Asynchronous Signal Handling EINTR handling

  • link from Use Case: Self-Pipe Trick (more with signals)

  • signalfd: link from

    • Synchronous Signal Handling

    • Event Loop Support: signalfd()

  • eventd, timerfd (add link from File Descriptors: Basics, look out for “jjj”)

• replace sidebar with topic (better for mobile)

• exercises see Event Loops

• toplevel livehacking explanation

  exit status

  • shell demo: grep jjj /etc/passwd

  • prog main() { return 0; } -> shell -> shell if, while,