本节介绍下kernel thread简单使用的例子实验.

 

我的系统：

 

joseph:/usr/src/linux-2.6.23/joseph# uname -a

Linux joseph 2.6.23 #1 SMP PREEMPT Fri May 6 18:02:45 CST 2011 i686 GNU/Linux

 

 

文件：

 

├── hello.c 

└── Makefile

 

 

1. hello.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kthread.h>
MODULE_LICENSE("Dual BSD/GPL");

//static DECLARE_WAIT_QUEUE_HEAD(myevent_waitqueue);
//rwlock_t myevent_lock;
static int mykthread(void* unused)
{
		daemonize("josephThread");
	
		// reuest delivery of SIGKILL
		allow_signal(SIGKILL);
		for(;;) {
				//relinquish the processor until the event occurs
				set_current_state(TASK_INTERRUPTIBLE);
				schedule();//allow other parts of the kernel to run
				//Die if I receive SIGKILL
				if (signal_pending(current)) break;
		}
	
		printk("josephThread out <------<<<<< /n");
		set_current_state(TASK_RUNNING);
		return 0;
}
static int hello_init(void)
{
		printk("Hello, I am a test module/n");
		//create my kernel thread
		
		printk("Create mythread<---------<<<<<<<</n");
		kernel_thread(mykthread, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND | SIGCHLD);
		return 0;
}
static void hello_exit(void)
{
		printk("Bye, my dear!/n Cruel world/n");
}

 

2. Makefile

 

obj-m := hello.o

 

另一个例子：

 

 

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>

MODULE_AUTHOR("T-bagwell_CU");
MODULE_LICENSE("GPL");

static DECLARE_WAIT_QUEUE_HEAD(myevent_waitqueue);
extern unsigned int myevent_id;


static int example_kernel_thread(void *unused)
{
        DECLARE_WAITQUEUE(wait, current);

        daemonize("create_by_T-bag");
        allow_signal(SIGKILL);
        add_wait_queue(&myevent_waitqueue, &wait);

        while(1){
                set_current_state(TASK_INTERRUPTIBLE);
                schedule();

                if(signal_pending(current)){
                        break;
                }
        }

        set_current_state(TASK_RUNNING);
        remove_wait_queue(&myevent_waitqueue, &wait);
        printk(KERN_WARNING "This is in example_kernel_thread\n");

        return 0;
}

static __init int init_hello_kernel_thread(void)
{
        int ret;

        ret=kernel_thread(example_kernel_thread, NULL,
                                  CLONE_FS | CLONE_FILES | CLONE_SIGHAND | SIGCHLD );

        if(unlikely(ret<0)){
                printk(KERN_WARNING "kernel_thread create failed \n");
        }
        else{
                printk(KERN_WARNING "kernel_thread create success \n");
        }

        return 0;
}

static __exit void cleanup_hello_kernel_thread(void)
{
        printk(KERN_WARNING "kernel_thread exit \n");
        return ;
}

module_init(init_hello_kernel_thread);
module_exit(cleanup_hello_kernel_thread);

 

写一个Makefile来编译这个module

KERNELDIR = /usr/src/kernels/2.6.27.5-117.fc10.i686
PWD := $(shell pwd)
obj-m := kernel_thread.o

modules:
            $(MAKE) -C $(KERNELDIR) M=$(PWD) modules
clean:
            rm -rf *.o *.ko test_chrdev Module.* module* *.mod.c