S6-SETUIDGID(8)

📦 version 2.15.1.0, in nixpkgs unstable

💅 s6-setuidgid (section 8, System Manager's Manual) 🎀

okay bestie, quick vibe check: this is s6-setuidgid, and honestly? it's giving backstage pass energy. it's the little tool that walks a program into the club as somebody else entirely. 🌈

✨ SYNOPSIS ✨

s6-setuidgid account prog...

that's it. that's the whole wig. account first, then whatever prog... you want it to become. 💖

🌸 DESCRIPTION 🌸

so here's the tea, and you're gonna want to sip it slowly because account has three whole moods:

  • if account is the empty string, then s6-setuidgid straight-up exec(3)s into prog... with zero state changes. no glow-up, no costume change, just ✨ directly into it ✨. literally nothing about you gets altered.
  • if account has a colon in it, it gets read as uid:gid — raw numbers, no name lookup, iykyk. 💅
  • otherwise? it's a username, and it gets looked up by name in the account database. classic.

if account is unknown, s6-setuidgid exits 1. that's the unhappy ending, bestie 😭 — no program gets executed, it just bails.

assuming the lookup worked, s6-setuidgid sets its (real and effective) uid and gid to those of account. yup, both. 👑

it also sets the list of supplementary groups to the correct one for account, according to the group database. so your group memberships match too — no leftovers from the old you. it's giving full transformation montage 🦋

then it executes into prog.... 🚀

⚠️ real talk though: unless account is empty, s6-setuidgid can only be run as root. no cap. it needs that power to give it away.

and that's literally its whole main-character purpose: dropping root privileges before starting a daemon. 🫶 the icon, the legend, the privilege-dropper. periodt.

🦋 SEE ALSO 🦋

the whole friend group, obviously:

this man page is ported from the authoritative documentation at: https://skarnet.org/software/s6/s6-setuidgid.html — go read the source, it's the blueprint 🧚

👑 AUTHORS 👑

  • Laurent Bercot
  • Alexis <flexibeast@gmail.com> (man page port)

anyway bestie, that's the page 💜 Debian, January 15, 2023 — stay safe, drop those privileges, and remember: with great root comes great responsibility. slay 💅🔥

📦 where this page comes from