1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
#![deny(missing_docs)]
#![cfg_attr(feature="nightly", feature(libc))]
#[macro_use]
extern crate log;
extern crate libc;
use std::fs::{OpenOptions, File};
use std::io::{Write, self};
use std::sync::Mutex;
use std::env;
use log::{Log, Metadata, Record, Level, LevelFilter, SetLoggerError};
pub struct KernelLog {
kmsg: Mutex<File>,
maxlevel: LevelFilter
}
impl KernelLog {
pub fn new() -> io::Result<KernelLog> {
KernelLog::with_level(LevelFilter::Trace)
}
pub fn from_env() -> io::Result<KernelLog> {
match env::var("KERNLOG_LEVEL") {
Err(_) => KernelLog::new(),
Ok(s) => match s.parse() {
Ok(filter) => KernelLog::with_level(filter),
Err(_) => KernelLog::new(),
}
}
}
pub fn with_level(filter: LevelFilter) -> io::Result<KernelLog> {
Ok(KernelLog {
kmsg: Mutex::new(OpenOptions::new().write(true).open("/dev/kmsg")?),
maxlevel: filter
})
}
}
impl Log for KernelLog {
fn enabled(&self, meta: &Metadata) -> bool {
meta.level() <= self.maxlevel
}
fn log(&self, record: &Record) {
if record.level() > self.maxlevel {
return;
}
let level: u8 = match record.level() {
Level::Error => 3,
Level::Warn => 4,
Level::Info => 5,
Level::Debug => 6,
Level::Trace => 7,
};
let mut buf = Vec::new();
writeln!(buf, "<{}>{}[{}]: {}", level, record.target(),
unsafe { ::libc::getpid() },
record.args()).unwrap();
if let Ok(mut kmsg) = self.kmsg.lock() {
let _ = kmsg.write(&buf);
let _ = kmsg.flush();
}
}
fn flush(&self) {}
}
#[derive(Debug)]
pub enum KernelLogInitError {
Io(io::Error),
Log(SetLoggerError)
}
impl std::fmt::Display for KernelLogInitError {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
KernelLogInitError::Io(err) => err.fmt(f),
KernelLogInitError::Log(err) => err.fmt(f),
}
}
}
impl std::error::Error for KernelLogInitError {
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
match self {
KernelLogInitError::Io(err) => Some(err),
KernelLogInitError::Log(err) => Some(err),
}
}
}
impl From<SetLoggerError> for KernelLogInitError {
fn from(err: SetLoggerError) -> Self {
KernelLogInitError::Log(err)
}
}
impl From<io::Error> for KernelLogInitError {
fn from(err: io::Error) -> Self {
KernelLogInitError::Io(err)
}
}
pub fn init() -> Result<(), KernelLogInitError> {
let klog = KernelLog::from_env()?;
let maxlevel = klog.maxlevel;
log::set_boxed_logger(Box::new(klog))?;
log::set_max_level(maxlevel);
Ok(())
}
#[cfg(test)]
mod tests {
use super::{KernelLog, init};
#[test]
fn log_to_kernel() {
init().unwrap();
debug!("hello, world!");
}
}