48 lines
1.6 KiB
Rust
48 lines
1.6 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Seq file bindings.
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//!
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//! C header: [`include/linux/seq_file.h`](../../../../include/linux/seq_file.h)
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use crate::{bindings, c_str, types::Opaque};
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/// A helper for implementing special files, where the complete contents can be generated on each
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/// access.
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pub struct SeqFile(Opaque<bindings::seq_file>);
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impl SeqFile {
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/// Creates a new [`SeqFile`] from a raw pointer.
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///
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/// # Safety
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///
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/// The caller must ensure that, for the duration of 'a, the pointer must point at a valid
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/// `seq_file` and that it will not be accessed via anything other than the returned reference.
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pub unsafe fn from_raw<'a>(ptr: *mut bindings::seq_file) -> &'a mut SeqFile {
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// SAFETY: The safety requirements guarantee the validity of the dereference, while the
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// `Credential` type being transparent makes the cast ok.
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unsafe { &mut *ptr.cast() }
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}
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/// Used by the [`seq_print`] macro.
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///
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/// [`seq_print`]: crate::seq_print
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pub fn call_printf(&mut self, args: core::fmt::Arguments<'_>) {
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// SAFETY: Passing a void pointer to `Arguments` is valid for `%pA`.
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unsafe {
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bindings::seq_printf(
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self.0.get(),
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c_str!("%pA").as_char_ptr(),
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&args as *const _ as *const core::ffi::c_void,
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);
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}
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}
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}
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/// Use for writing to a [`SeqFile`] with the ordinary Rust formatting syntax.
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#[macro_export]
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macro_rules! seq_print {
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($m:expr, $($arg:tt)+) => (
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$m.call_printf(format_args!($($arg)+))
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);
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}
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