sock_read_xattr(9)

🌸 NAME 🌸

sock_read_xattr — read a user.* xattr from a socket's sockfs inode 💖

okay so bestie, this page lives in the Kernel API Manual (sock_read_xattr(9)), and it's giving "tiny helper, big sockfs energy" ✨ no cap.

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✨ SYNOPSIS ✨

int sock_read_xattr (struct socket *sock , const char *name , void
       *value , size_t size );

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🎀 ARGUMENTS 🎀

• sock — the socket whose inode holds the xattr 🧦 literally the main character here.
• name — the full xattr name, e.g. "user.bpf_test" ✨ yes, the whole name, prefix included.
• value — output buffer 🫶 this is where the value lands.
• size — size of value in bytes 💅 bytes, not vibes.

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🦋 DESCRIPTION 🦋

So here's the tea: SOCK_INODE is valid only for sockfs sockets, periodt. sock_from_file rejects anything else (e.g. tun, tap) 🙈.

This lookup is lockless: simple_xattr_get looks up the value under RCU, and there is no inode lock 👑. The inode lock is literally not invited to this party.

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🌈 RETURN 🌈

On success you get the length of the value 💖. On error you get a negative errno 😭.

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💜 SEE ALSO 💜

Kernel file ./net/socket.c is the main character, and the whole friend group is: move_addr_to_kernel(9), move_addr_to_user(9), sock_alloc_file(9), sock_from_file(9), sockfd_lookup(9), sock_alloc(9), sock_release(9), sock_sendmsg(9), kernel_sendmsg(9), sock_recvmsg(9), kernel_recvmsg(9), sock_create_lite(9), __sock_create(9), sock_create(9), sock_create_kern(9), sock_register(9), sock_unregister(9), kernel_bind(9), kernel_listen(9), kernel_accept(9), kernel_connect(9), kernel_getsockname(9), kernel_getpeername(9), kernel_sock_shutdown(9), kernel_sock_ip_overhead(9) ✨.

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that's the page, bestie 🫶 source/version: ./net ✨ date: October 2026 🎀 and yes, we close with sock_read_xattr(9) 💅 periodt.