VOP_VPTOCNP(9)

💅 VOP_VPTOCNP — the "who even IS this vnode" girlie 💅

okay so bestie, welcome to VOP_VPTOCNP(9) from the Kernel Developer's Manual. this is the glow-up where a vnode finally learns its own name 🎀

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✨ NAME ✨

VOP_VPTOCNP — translate a vnode to its component name 🦋

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🌸 SYNOPSIS 🌸

#include <sys/param.h>
#include <sys/ucred.h>
#include <sys/vnode.h>

int
VOP_VPTOCNP(struct vnode *vp, struct vnode **dvp, struct ucred *cred,
    char *buf, int *buflen);

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💖 DESCRIPTION 💖

so basically this takes a vnode and figures out its component name, then writes that name to the head of the buffer you handed it (buf). it's giving "identity reveal" and honestly? iconic.

• vp — the vnode we're translating, the main character 🫶
• dvp — the vnode of the parent directory of vp (its mom, lowkey)
• cred — the caller credentials, like your ID at the door 🎟️
• buf — the buffer where the component name gets prepended (head of the buffer, no cap)
• buflen — how much room is left in that buffer, so we don't overflow and have a whole situation 😭

the default implementation of VOP_VPTOCNP scans through vp's parent directory looking for a dirent with a matching file number 🔍. but heads up: if vp is not a directory, then VOP_VPTOCNP returns ENOENT. not me getting rejected fr fr 💀

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🔒 LOCKS 🔒

the vnode should be locked on entry and will still be locked on exit. the parent directory vnode will be unlocked on a successful exit 🎉 — however, it will have its use count incremented. so it's out of lock jail but still on the books, iykyk 👑

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⭐ RETURN VALUES ⭐

zero is returned on success 🥳, otherwise an error code is returned. periodt.

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🌈 ERRORS 🌈

• [ENOMEM] — the buffer was not large enough to hold the vnode's component name. she's too big for that box, literally 🙈
• [ENOENT] — the vnode was not found on the file system. she's not on the guest list 💀

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👀 SEE ALSO 👀

vnode(9), VOP_LOOKUP(9)

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🚧 NOTES 🚧

this interface is a work in progress. so bestie, she's still in her experimental era 🧚 don't be weird about it.

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📜 HISTORY 📜

the function VOP_VPTOCNP appeared in FreeBSD 8.0. a true 2009 legend, no notes 🌟

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💜 AUTHORS 💜

this manual page was written by Joe Marcus Clarke. thank you king, we are obsessed 🫶

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and that's the whole page bestie!! this little doc came to you from the Debian crew and it's dated March 8, 2015 — oldie but a goodie, still serving looks in VOP_VPTOCNP(9) 💅✨