Linux下类FreeBSD uprintf实现
uprintf是FreeBSD下内核函数, 作用是将内核信息输出到当前的tty给用户显示, 非常方便. 而linux下无此函数, 不过可以通过借用tty设备来达到目的.以下是代码实现.
Kernel version: 2.6.28
gcc Version: 4.3.3
#include <linux/module.h> /* Needed by all modules */#include <linux/kernel.h> /* Needed for KERN_INFO */#include <linux/init.h>#include <linux/syscalls.h>#include <linux/unistd.h>#include <linux/sched.h> /* For current */#include <linux/tty.h> /* For the tty declarations */static void tty_print(const char *str){ struct tty_struct *cur_tty; // 取得当前的tty if ( current->signal ) cur_tty = current->signal->tty; else cur_tty = NULL; // 调用当前tty设备驱动write操作 if ( cur_tty ) { if ( cur_tty->driver ) { cur_tty->driver->ops->write( cur_tty, str, strlen( str ) );/* cur_tty->driver->ops->write( cur_tty, "\015\012", 2 );*/ } }}int uprintf(const char *fmt, ...){ char printf_buf; va_list args; int printed; va_start(args, fmt); printed = vsprintf(printf_buf, fmt, args); va_end(args); tty_print( printf_buf ); return 0;}EXPORT_SYMBOL( uprintf );static int __init uprintf_init(void){ uprintf( "hello init\n" ); return 0;}static void __exit uprintf_fini(void){ uprintf( "hello end\n" );}module_init(uprintf_init);module_exit(uprintf_fini);
Makefile
obj-m = uprintf.ouprintf-objs = main.oKVERSION = $(shell uname -r)all: make -C /lib/modules/$(KVERSION)/build M=$(PWD) modulesclean: make -C /lib/modules/$(KVERSION)/build M=$(PWD) clean rm -f Module.markersmodules.order
参考:
Replacing printk's
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