logging: bugfix #137: Init log module to enable logging macros

os/src/logging.rs

@@ -0,0 +1,47 @@
+/*！
+
+本模块利用 log crate 为你提供了日志功能，使用方式见 main.rs.
+
+*/
+
+use log::{self, Level, LevelFilter, Log, Metadata, Record};
+
+struct SimpleLogger;
+
+impl Log for SimpleLogger {
+    fn enabled(&self, _metadata: &Metadata) -> bool {
+        true
+    }
+    fn log(&self, record: &Record) {
+        if !self.enabled(record.metadata()) {
+            return;
+        }
+        let color = match record.level() {
+            Level::Error => 31, // Red
+            Level::Warn => 93,  // BrightYellow
+            Level::Info => 34,  // Blue
+            Level::Debug => 32, // Green
+            Level::Trace => 90, // BrightBlack
+        };
+        println!(
+            "\u{1B}[{}m[{:>5}] {}\u{1B}[0m",
+            color,
+            record.level(),
+            record.args(),
+        );
+    }
+    fn flush(&self) {}
+}
+
+pub fn init() {
+    static LOGGER: SimpleLogger = SimpleLogger;
+    log::set_logger(&LOGGER).unwrap();
+    log::set_max_level(match option_env!("LOG") {
+        Some("ERROR") => LevelFilter::Error,
+        Some("WARN") => LevelFilter::Warn,
+        Some("INFO") => LevelFilter::Info,
+        Some("DEBUG") => LevelFilter::Debug,
+        Some("TRACE") => LevelFilter::Trace,
+        _ => LevelFilter::Info,
+    });
+}

os/src/main.rs

@@ -31,6 +31,8 @@ extern crate alloc;
 #[macro_use]
 extern crate bitflags;
 
+use log::*;
+
 #[path = "boards/qemu.rs"]
 mod board;
 
@@ -40,6 +42,7 @@ mod config;
 mod drivers;
 pub mod fs;
 pub mod lang_items;
+mod logging;
 pub mod mm;
 pub mod sbi;
 pub mod sync;
@@ -67,7 +70,8 @@ fn clear_bss() {
 /// the rust entry-point of os
 pub fn rust_main() -> ! {
     clear_bss();
-    println!("[kernel] Hello, world!");
+    logging::init();
+    info!("[kernel] Hello, world!");
     mm::init();
     mm::remap_test();
     trap::init();