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//! rsapi — the kernel↔binary ABI (ADR 0006).
//!
//! One versioned `Exports` table is constructed per invocation and handed
//! to the binary's entry point. The header starts with a magic and a
//! `version: u32` so a future kernel can keep old binaries working
//! (dispatch on the version, never on struct layout).
//!
//! Everything here is `no_std`-clean: plain structs and function pointers,
//! no allocation, no rsnix dependency — binaries link only this crate.
#![no_std]
/// Table magic: "RSEX".
pub const EXPORTS_MAGIC: u32 = 0x5245_5853;
/// ABI revision. Bump on any signature change; the kernel refuses to run
/// binaries whose required major exceeds its own.
pub const ABI_VERSION: u32 = 1;
/// Entry-point signature. `extern "C"` on the x86_64-unknown-uefi
/// target is the Win64 convention: the three arguments arrive in
/// RCX/RDX/R8 on both sides of the table.
pub type EntryPoint =
extern "C" fn(exports: &'static Exports, argc: usize, argv: *const Arg) -> i32;
/// One C-style argv element: pointer + length (rs-dos strings are not
/// NUL-terminated in memory).
#[derive(Clone, Copy)]
pub struct Arg {
pub ptr: *const u8,
pub len: usize,
}
/// A line of text handed across the ABI (stream I/O).
#[derive(Clone, Copy)]
pub struct Line {
pub ptr: *const u8,
pub len: usize,
}
impl Line {
/// Borrow as a &str (lossy is impossible: lines are always UTF-8).
pub fn as_str(&self) -> &'static str {
unsafe { core::str::from_utf8_unchecked(core::slice::from_raw_parts(self.ptr, self.len)) }
}
}
/// Outcome of `get_line`.
#[derive(Clone, Copy, PartialEq, Eq)]
pub enum StreamResult {
/// A line is available (see `out`).
Line,
/// Input exhausted.
Eof,
/// Aborted (^C or upstream killed); stop immediately.
Abort,
}
// ---------------------------------------------------------------------------
// Exports table — v1
// ---------------------------------------------------------------------------
/// The function table a binary receives. Layout is fixed by `version`;
/// new functions are appended, existing ones never move.
#[repr(C)]
pub struct Exports {
// ---- header ----
pub magic: u32,
pub version: u32,
// ---- console / streams (v1) ----
/// Print one line to the command's output stream.
/// Returns false when the consumer says stop (pager quit / head limit /
/// ^C) — the binary should wrap up promptly.
pub put_line: fn(line: Line) -> bool,
/// Read one line from the command's input stream (only meaningful for
/// input consumers like cat/hexdump; otherwise returns Eof).
/// `out` receives the line when the result is `StreamResult::Line`.
pub get_line: fn(out: &mut Line) -> StreamResult,
// ---- lifecycle (v1) ----
/// Log one line to the kernel log ring (/dev/klog).
pub log_line: fn(line: Line),
/// Exit code for the completion message to the spawner.
/// (Calling this is optional; returning from the entry point exits 0.)
pub exit: fn(code: i32) -> !,
}
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