initial_idmapping(9)

📦 version 7.3.1, in nixpkgs unstable

✨ initial_idmapping(9) ✨

okay so bestie, welcome to the Kernel API Manual — today's episode is initial_idmapping(9) and it's honestly a little icon. short, sweet, does exactly one thing. we love a focused queen 💅

🌸 NAME 🌸

initial_idmapping — check whether this is the initial mapping

like. that's the whole job. she woke up, she checks a thing, she goes home. 👑

🦋 SYNOPSIS 🦋

bool initial_idmapping (const struct user_namespace *ns );

no cap, that's the entire vibe. one function, one argument, returns a bool. minimalist. clean. ate.

🎀 ARGUMENTS 🎀

  • ns — the idmapping you want to check, typed as a const struct user_namespace *. that's it, that's the parameter. she's the main character of this function and she's coming in as a pointer to a const user namespace 🫶

⭐ DESCRIPTION ⭐

okay so here's the tea 🍓 — this function checks whether the mapping you handed it is the initial mapping.

and what does "initial mapping" mean, you ask? it means the identity situation, bestie. it maps:

  • 0 to 0
  • 1 to 1
  • [...]
  • 1000 to 1000
  • [...]

every number just... maps to itself. no translation, no transformation, just pure unbothered identity-energy. it's giving "i am who i am" ✨ literally the mapping equivalent of showing up in your own clothes to your own party.

💖 RETURN 💖

  • true — yes bestie, this is the initial mapping 🌈
  • false — nope, it is not 💀

🔥 SEE ALSO 🔥

go give these siblings some love, they're all in the kernel file ./fs/mnt_idmapping.c and they're all lowkey iconic:

iykyk 👀

ngl bestie, this one's a quick read — no scary warnings, no deprecated nonsense, no undefined behaviour lurking in the shadows. just a lil identity check. enjoy it while it lasts 🧚

and that's the whole page!! mwah 💋 this little drop came to you from the source ./fs, stamped October 2026, and it's filed under initial_idmapping(9) forever and ever. go forth and check your mappings, bestie 💜🦋

📦 where this page comes from