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// SPDX-License-Identifier: GPL-2.0
use core::cmp;
use core::fmt;
use crate::bindings;
use crate::c_types::c_int;
#[doc(hidden)]
pub fn printk(s: &[u8]) {
// Don't copy the trailing NUL from `KERN_INFO`.
let mut fmt_str = [0; bindings::KERN_INFO.len() - 1 + b"%.*s\0".len()];
fmt_str[..bindings::KERN_INFO.len() - 1]
.copy_from_slice(&bindings::KERN_INFO[..bindings::KERN_INFO.len() - 1]);
fmt_str[bindings::KERN_INFO.len() - 1..].copy_from_slice(b"%.*s\0");
// TODO: I believe printk never fails
unsafe { bindings::printk(fmt_str.as_ptr() as _, s.len() as c_int, s.as_ptr()) };
}
// From kernel/print/printk.c
const LOG_LINE_MAX: usize = 1024 - 32;
#[doc(hidden)]
pub struct LogLineWriter {
data: [u8; LOG_LINE_MAX],
pos: usize,
}
#[allow(clippy::new_without_default)]
impl LogLineWriter {
pub fn new() -> LogLineWriter {
LogLineWriter {
data: [0u8; LOG_LINE_MAX],
pos: 0,
}
}
pub fn as_bytes(&self) -> &[u8] {
&self.data[..self.pos]
}
}
impl fmt::Write for LogLineWriter {
fn write_str(&mut self, s: &str) -> fmt::Result {
let copy_len = cmp::min(LOG_LINE_MAX - self.pos, s.as_bytes().len());
self.data[self.pos..self.pos + copy_len].copy_from_slice(&s.as_bytes()[..copy_len]);
self.pos += copy_len;
Ok(())
}
}
/// [`println!`] functions the same as it does in `std`, except instead of
/// printing to `stdout`, it writes to the kernel console at the `KERN_INFO`
/// level.
///
/// [`println!`]: https://doc.rust-lang.org/stable/std/macro.println.html
#[macro_export]
macro_rules! println {
() => ({
$crate::printk::printk("\n".as_bytes());
});
($fmt:expr) => ({
$crate::printk::printk(concat!($fmt, "\n").as_bytes());
});
($fmt:expr, $($arg:tt)*) => ({
use ::core::fmt;
let mut writer = $crate::printk::LogLineWriter::new();
let _ = fmt::write(&mut writer, format_args!(concat!($fmt, "\n"), $($arg)*)).unwrap();
$crate::printk::printk(writer.as_bytes());
});
}
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