ioctl_nsfs(2)

bestie!!! welcome to ioctl_nsfs(2), aka the System Calls Manual page for ioctl() operations that deal with Linux namespaces. it's giving very niche, very powerful, very "trust me i know what i'm doing" 💅

🎀 NAME 🎀

ioctl_nsfs — ioctl() operations for Linux namespaces. periodt.

✨ SYNOPSIS ✨

#include <linux/nsfs.h>  /* Definition of NS_* constants */
#include <sys/ioctl.h>

int ioctl(int fd, unsigned long op, ...);

💖 DESCRIPTION 💖

okay so this whole page is the lil hub for namespace-flavored ioctl() ops. it doesn't spill every detail itself; it points you to the specific 2const pages. no cap.

🦋 Discovering namespace relationships 🦋

this is the relationship lore section, bestie:

• NS_GET_USERNS(2const)
• NS_GET_PARENT(2const)

🔍 Discovering the namespace type 🔍

• NS_GET_NSTYPE(2const)

👑 Discovering the owner of a user namespace 👑

• NS_GET_OWNER_UID(2const)

😭 ERRORS 😭

• ENOTTY — fd does not refer to a /proc/pid/ns/* file.

so if you see this, the file descriptor is not giving namespace file energy. check yourself before you wreck yourself 🫶

🌈 STANDARDS 🌈

Linux.

👀 SEE ALSO 👀

• ioctl(2)
• fstat(2)
• proc(5)
• namespaces(7)

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okay that's the page!! mwah 💋 this one came from Linux man-pages 6.20, dated 2026-02-08. go be iconic with your namespaces, bestie 💅✨