io_uring_ring_dontfork(3)

💖 io_uring_ring_dontfork — bestie edition 💖

ok so this is a page from the liburing Manual, and it's about io_uring_ring_dontfork(3). yes the name is a mouthful, we're gonna get through it together 🫶

✨ NAME ✨

io_uring_ring_dontfork — the vibe is: keep your ring memory from getting shared after a fork 🍴🚫

✨ SYNOPSIS ✨

#include <liburing.h>

int io_uring_ring_dontfork(struct io_uring *ring);

like, that's it. one include, one function. slay ✨

✨ DESCRIPTION ✨

okay so bestie, listen. the io_uring_ring_dontfork(3) function makes it so that the mmap'ed rings for the io_uring instance ring are NOT available to a child process after a fork(2). like, the kid does not get access. periodt 💅

how does it do that? it calls madvise(2) with MADV_DONTFORK on the mmap'ed ranges, which is the actual mechanism stopping them from being shared with child processes. 🧚

and why would you even want that? because sometimes the parent wants exclusive access to the ring and literally does not want the child to be able to touch it, access it, or interfere with it. main character energy: the ring belongs to the parent, and that's the whole story 👑

✨ RETURN VALUE ✨

• Returns 0 on success. 🎉 we love a clean win
• On error, it returns a negative errno value. so like, don't expect a nice little -1, check your negative errnos fr fr 💀

✨ SEE ALSO ✨

• io_uring_queue_init(3)
• madvise(2)
• fork(2)

go read those too, they're all part of the same friend group 🌈

and that's the whole page!! thanks for reading, ily 💜 this was liburing-2.4, dated January 18, 2025, and it lives in the liburing Manual — now go forth and protect your rings from your forked children 🦋✨