STRUCT BINDER_TXN_FD_FIXUP(9)

💅 struct binder_txn_fd_fixup — transaction fd fixup list element

okay bestie so this is struct binder_txn_fd_fixup(9) from the Kernel API Manual, and honestly? it's giving tiny-but-load-bearing. let's get into it 🎀

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✨ NAME ✨

struct binder_txn_fd_fixup — transaction fd fixup list element. that's it, that's the whole vibe. it's one lil list element, but it's doing a lot of work, iykyk 💅

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🌸 SYNOPSIS 🌸

struct binder_txn_fd_fixup {
    struct list_head fixup_entry;
    struct file *file;
    size_t offset;
    int target_fd;
 };

look at her. four fields, zero drama. copy her exactly, no cap, don't go "fixing" the spacing bestie 💖

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🦋 Members 🦋

• fixup_entry — the list entry, aka her little handle so she can be chained up in a list. it's a list_head, it's iconic, moving on ✨
• file — the struct file that's gonna get associated with the new fd. she's the whole reason we're here tbh 🫶
• offset — the offset in the buffer data pointing at this fixup. a size_t, so she's got range 💜
• target_fd — the fd the target process should use to install file. an int, cute, love that for her 🎀

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🔥 Description 🔥

so this is a list element for fd fixups in a transaction, fr fr. here's the tea: file descriptors need to be allocated in the context of the target process, so we can't just do it wherever we feel like it. instead, we pass each fd that needs processing along in this struct. lowkey the whole setup is just a little delivery service for fds 👑✨

ngl this is one of those "small struct, big responsibilities" situations. she's not the main character, she's the main character's handler. 💀

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⭐ SEE ALSO ⭐

Kernel file ./drivers/android/binder_internal.h — plus the whole friend group, go say hi:

• struct binder_device(9)
• struct binder_work(9)
• struct binder_node(9)
• struct binder_ref_data(9)
• struct binder_ref(9)
• struct binder_proc(9)
• struct binder_thread(9)
• struct binder_object(9)

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and that's the page bestie!! source is ./drivers/android, dated October 2026 — so go forth, allocate those fds in the right process context, and slay 🧚💖🌸