Rust code shared from the playground

playground.rs

use linux;
use log;
use core::fmt::Write;
use core::fmt;
// Linux guards the kernel ring buffer with a lock.
use core::cell::UnsafeCell;


use log::{LogRecord, LogLevel, LogMetadata};

#[derive(Default)]
struct DMesgLogger(());

impl fmt::Write for DMesgLogger {
    fn write_str(&mut self, s: &str) -> Result<(), fmt::Error> {
        unsafe {
            linux::printk(cstring!("%s\n"), s.as_ptr());
        }
        Ok(())
    }
}


impl log::Log for DMesgLogger {
    fn enabled(&self, metadata: &LogMetadata) -> bool {
        metadata.level() <= LogLevel::Info
    }

    fn log(&self, record: &LogRecord) {
        if self.enabled(record.metadata()) {
            let _ = write!(self, "{:?}\0", record);
        }
    }
}

pub fn init() -> Result<(), log::SetLoggerError> {
    unsafe {
        log::set_logger_raw(|max_log_level| {
            static LOGGER: DMesgLogger = DMesgLogger(());
            max_log_level.set(log::LogLevelFilter::Info);
            &LOGGER
        })
    }
}

pub fn fini() { }

pub fn shutdown() -> Result<(), log::ShutdownLoggerError> {
    log::shutdown_logger_raw().map(|_logger| {})
}