projects/linux·blob master · refs

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1// SPDX-License-Identifier: GPL-2.0
2
3//! Seq file bindings.
4//!
5//! C header: [`include/linux/seq_file.h`](srctree/include/linux/seq_file.h)
6
7use crate::{bindings, fmt, str::CStrExt as _, types::NotThreadSafe, types::Opaque};
8
9/// A utility for generating the contents of a seq file.
10#[repr(transparent)]
11pub struct SeqFile {
12 inner: Opaque<bindings::seq_file>,
13 _not_send: NotThreadSafe,
14}
15
16impl SeqFile {
17 /// Creates a new [`SeqFile`] from a raw pointer.
18 ///
19 /// # Safety
20 ///
21 /// The caller must ensure that for the duration of `'a` the following is satisfied:
22 /// * The pointer points at a valid `struct seq_file`.
23 /// * The `struct seq_file` is not accessed from any other thread.
24 pub unsafe fn from_raw<'a>(ptr: *mut bindings::seq_file) -> &'a SeqFile {
25 // SAFETY: The caller ensures that the reference is valid for 'a. There's no way to trigger
26 // a data race by using the `&SeqFile` since this is the only thread accessing the seq_file.
27 //
28 // CAST: The layout of `struct seq_file` and `SeqFile` is compatible.
29 unsafe { &*ptr.cast() }
30 }
31
32 /// Used by the [`seq_print`] macro.
33 #[inline]
34 pub fn call_printf(&self, args: fmt::Arguments<'_>) {
35 // SAFETY: Passing a void pointer to `Arguments` is valid for `%pA`.
36 unsafe {
37 bindings::seq_printf(
38 self.inner.get(),
39 c"%pA".as_char_ptr(),
40 core::ptr::from_ref(&args).cast::<crate::ffi::c_void>(),
41 );
42 }
43 }
44}
45
46/// Write to a [`SeqFile`] with the ordinary Rust formatting syntax.
47#[macro_export]
48macro_rules! seq_print {
49 ($m:expr, $($arg:tt)+) => (
50 $m.call_printf($crate::prelude::fmt!($($arg)+))
51 );
52}
53pub use seq_print;