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Comment by flakes | Hacker News Reader

The best part of this thread was the link to the discussion on the removal of pid caching in `getpid` causing regressions in systemd https://bugzilla.redhat.com/show_bug.cgi?id=1469670

I've been on a code-deleting rampage lately, killing off many minor features that add a lot of complexity for seemingly little gain. Glad I don't have anyone interrogating me like this!

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The snark here is impressive:

> in order to quickly fix this pressing matter, I've attached code that I believe will fix your issue. It uses a custom caching mechanism and fits well into the systemd ecosystem.

    pid_t systemd_getpid(void) {
     return 0;
    }

It's kind of a dick answer, imo.

I'm really not sure if it's perfectly context sensitive or too much even for systemd.

But dick answers is the specialty of the systemd development team. I wouldn't want to get into a contest against them.

That one had me laughing really hard haha

That was interesting - "Umm, this change causes major slowdowns in various bits of systemd code, which assumes that getpid() is fast. libsystemd uses getpid() to detect when processes fork". A regular userspace program doesn't need to detect when a fork() has occurred since its whats doing the fork().

Caching the result of getpid causes you to need to change the value after it's forked. So fork must be wrapped if getpid is wrapped.

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