KLDUNLOAD(2)

✨ KLDUNLOAD — bestie's guide to yeeting kernel modules ✨

okay so real talk, this is the kldunload / kldunloadf manual page, and it's giving unload kld files energy 💖 if you're here, you're the kind of girl who loads a kernel module and then goes "…actually no" and that is VALID.

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📚 LIBRARY

Standard C Library (libc, -lc) 🎀 like obviously, she lives in libc, that's her home.

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✨ SYNOPSIS

#include <sys/param.h>
#include <sys/linker.h>

int
kldunload(int fileid);

int
kldunloadf(int fileid, int flags);

look at her. two little functions. so demure. so mindful. 🦋

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💅 DESCRIPTION

okay so the kldunload() system call unloads a kld file from the kernel that was previously linked via kldload(2). basically it's the "undo" button for modules, and no cap, we love a reversible decision 🫶

the kldunloadf() system call is the same girl but she takes an additional flags argument, and that flags can be one of these two:

• LINKER_UNLOAD_NORMAL — gives you the exact same behavior as kldunload(), i.e. the classic. the OG. the default vibe. ✨
• LINKER_UNLOAD_FORCE — this one causes the unload to ignore a failure to quiesce the module. yes bestie she said what she said, she's not waiting for the module to calm down, she's just leaving 💀

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🫶 RETURN VALUES

upon successful completion, the value 0 is returned. otherwise the value -1 is returned and the global variable errno is set to indicate the error. so like. 0 = slay, -1 = check errno, periodt. 👑

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😭 ERRORS

the file referred to by fileid is unloaded unless one of these happens (and if one happens, bestie, she is NOT unloading):

• [EPERM] — you do not have access to unlink the file from the kernel. not your module, not your business 🙈
• [ENOENT] — the file was not found. she's not there. she never was. ghosted fr fr.
• [EBUSY] — you attempted to unload a file linked by the kernel. nope. the kernel is holding on with both hands. 💀
• [EINVAL] — the kldunloadf() system call was passed invalid flags. you handed her something she doesn't recognize and she's judging you (gently, lovingly) 🎀

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👀 SEE ALSO

kldfind(2), kldfirstmod(2), kldload(2), kldnext(2), kldstat(2), kldsym(2), modfind(2), modfnext(2), modnext(2), modstat(2), kld(4), kldunload(8) — the whole friend group, go say hi, they're all iconic in their own way 🌈

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🌸 HISTORY

the kld interface first appeared in FreeBSD 3.0. she's a legacy queen and she's been serving since day one 👑

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💡 friendly reminder bestie: unload responsibly. LINKER_UNLOAD_FORCE is right there and it does exactly what it sounds like it does.

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and that's the whole page!! this came from the Debian edition, dated December 25, 2008 — a lil Christmas gift of a manpage 🎁 — and honestly? she ate. mwah. 💅💖✨