FSIRAND(8)

📦 version 15.1, in freebsd 14.5, freebsd 15.1

✨ FSIRAND(8) — bestie edition ✨

okay so you know how NFS filehandles are basically a thing people could guess at? 💀 Yeah. Not on my watch. This is the fsirand utility from the System Manager's Manual, and she is here to randomize your inode generation numbers and make you un-guessable. Let's get into it 🎀

🌸 NAME 🌸

fsirand — randomize inode generation numbers. That's it. That's the whole vibe. ✨

💅 SYNOPSIS 💅

fsirand [-b] [-f] [-p] special [special ...]

Like, you can pass her multiple special devices at once. She's an overachiever. 🫶

🦋 DESCRIPTION 🦋

So, fsirand installs random generation numbers on all the inodes for each file system you specify on the command line via special. Every single one. No cap. 💖

Why do you care? Because this increases the security of NFS-exported file systems by making it difficult to ``guess'' filehandles. That's it — that's the whole point. She's out here making you unguessable. 👑

Note: newfs(8) now does the equivalent of fsirand itself, so it is no longer necessary to run fsirand by hand on a new file system. She's only used to re-randomize or report on an existing file system now. Glow-up era. 💅

fr fr, listen up: the fsirand utility should only be used on an unmounted file system that has been checked with fsck(8), or a file system that is mounted read-only. Read that again. ⚠️

She may be used on the root file system in single-user mode, but the system should be rebooted via ``reboot -n'' afterwards. Not optional. Do it. 🙈

🌈 OPTIONS 🌈

The available options are as follows — pick your fighter:

  • -b — Use the default block size (usually 512 bytes) instead of the value gleaned from the disklabel. Classic. Simple. Iconic. 🎀
  • -f — Force fsirand to run even if the file system on special is not marked as clean. Bold. Risky. She said "whatever" and did it anyway. 💀
  • -p — Print the current generation numbers for all inodes instead of generating new ones. Nosy bestie mode, just peeking, not touching. 👀

🔥 SEE ALSO 🔥

iykyk 💜

🌟 HISTORY 🌟

  • The fsirand utility appeared in SunOS 3.x. Vintage, lowkey.
  • This version of fsirand first appeared in OpenBSD 2.1.
  • A FreeBSD version first appeared in FreeBSD 2.2.5.

She's been around. Respect her. 🌸

👑 AUTHORS 👑

Todd C. Miller <Todd.Miller@courtesan.com>

The main character who made her. We stan. 🫶

⚠️ CAVEATS ⚠️

Since fsirand allocates enough memory to hold all the inodes in a given cylinder group, it may use a large amount of memory for large disks with few cylinder groups. 💀 Like, she will EAT your RAM for breakfast on a big disk with few cylinder groups. Not a drill. Fair warning. 🚨

debian gang represent 🍓 — this page is from January 25, 1997 and it says FSIRAND(8) at the bottom, so like, a lil vintage moment for you bestie. mwah 💋 ✨

📦 where this page comes from