Linux printk() 打印到哪里？
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Where does printk() print to?
提问by molleman
Just a quick question on printk() function at the kernel level, if I call this where will the message be printed to?(I'm using Ubuntu on i386 arch with the latest kernel download)
只是一个关于内核级别的 printk() 函数的快速问题，如果我调用它，消息将打印到哪里？（我在 i386 arch 上使用 Ubuntu 并下载了最新的内核）
can't find it anywhere,
到处都找不到，
If someone could also point me in the right direction for some sort of manual for the printk() function it would be great!
如果有人也可以为我指明正确的方向，为 printk() 函数提供某种手册，那就太好了！
采纳答案by Alan Haggai Alavi
dmesgshould display printkmessages.
dmesg应该显示printk消息。
回答by Ignacio Vazquez-Abrams
The printk(9)man page has a verysmall bit of information on it. In short, it gets sent to the log buffer, where a syslog daemon can pick it up and handle it. It also gets sent to the console if its loglevel is high enough (see dmesg(1)for that bit).
该printk(9)手册页有一个非常的上信息的小一点。简而言之，它被发送到日志缓冲区，在那里 syslog 守护程序可以拾取并处理它。如果它的日志级别足够高，它也会被发送到控制台（请参阅dmesg(1)该位）。
回答by zwol
printkmessages go to the kernel log message buffer, which can be exposed in a variety of ways depending on system configuration. The shell command dmesgwill show them, and they should also be being copied to files in /var/logby the syslogdaemon. It's possible to get them logged to a serial console or a text-mode virtual terminal, but I don't remember how offhand.
printk消息进入内核日志消息缓冲区，可以根据系统配置以多种方式公开。shell命令dmesg将显示他们，而他们也应该被复制到文件/var/log由syslog守护进程。可以将它们记录到串行控制台或文本模式虚拟终端，但我不记得是多么随意。
回答by gsbabil
If you have put some printk()statements in the kernel module to debug and trying to capture the outputs as they are printk'ed, what you are looking for is klogd. Perform a man klogdfor more detains and options.
如果您printk()在内核模块中放置了一些语句以进行调试并尝试在打印输出时捕获输出，那么您正在寻找的是klogd. 执行 aman klogd以获取更多拘留和选项。
Here's a wrapper script for klogdthat I coded a while back to ease some quick debugging pain:
这klogd是我编码的一个包装脚本，以减轻一些快速调试的痛苦：
#!/bin/bash
function bashtrap()
{
echo
echo -n "[+] stopping klogd ... "
pids=`ps aux | grep klogd | awk '{print }'`
for pid in $pids
do
kill SIGTERM $pid 2> /dev/null
done
echo "done"
if [ ]
then
exit;
fi
}
sync
bashtrap
klogd -x -f - -n -c 8 2>&1 1 | tee klog.txt & klog_pid=$!;
echo "[+] klogd started"
echo "[+] press ctrl+c to exit ... $klog_pid"
sync
trap "bashtrap 1" SIGINT
while [ 1 ]
do
sleep 3
echo -n "."
done
ps aux | grep klogd
回答by ichabod
Look for /dev/kmsgon your system.
/dev/kmsg在您的系统上查找。
