receive_fd(9)

💖 receive_fd(9) 💖

🌸 NAME 🌸

okay so bestie, welcome to the Kernel API Manual — this is the page for receive_fd(9), and the name line is literally "receive_fd — install received file into file descriptor table." main character energy fr fr. ✨

✨ SYNOPSIS ✨

int receive_fd (struct file *file , int __user *ufd , unsigned int
       o_flags );

🎀 ARGUMENTS 🎀

• file — the struct file that was received from another process. it's giving "incoming file, handle with care" 💅
• ufd — a __user pointer to write the new fd number to. yes bestie, userspace pointer 🫶
• o_flags — the O_* flags to apply to the new fd entry. slay, flags ✨

💅 DESCRIPTION 💅

Okay so here's the vibe check: receive_fd() installs a received file into the file descriptor table, with the appropriate checks and count updates. no cap. It optionally writes the fd number to userspace, but only if ufd is non-NULL. 🌸

This helper handles its own reference counting of the incoming struct file. not me obsessing over this, but it's iconic. 💖

Returns the newly install fd or -ve on error. 😭 yes, that's the wording, bestie — keep it moving.

🦋 SEE ALSO 🦋

Over in the Kernel file ./fs/file.c, the icons are (iykyk):

• __file_ref_put(9)
• fd_install(9)
• file_close_fd_locked(9)
• last_fd(9)
• sys_close_range(9)
• file_close_fd(9)
• get_file_rcu(9)
• get_file_active(9)

💖 and that's the tea: source/version ./fs, October 2026, receive_fd(9) — bye bestie, periodt! 💖