#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <asm/uaccess.h>
#include <linux/slab.h>
#define LEN 21
int len,has_read;
char *msg;
int read_proc(struct file *filp,char *buf,size_t count,loff_t *offp ) {
struct timespec time_ckt;
time_ckt=current_kernel_time();
unsigned long p=time_ckt.tv_sec;
int len_sec=0;
while(p/=10){
len_sec++;
}
len_sec++;
int i;
p=time_ckt.tv_sec;
for(i=0;i<len_sec;i++){
int x=1;
int j;
for(j=i+1;j<len_sec;j++){
x*=10;
}
msg[i]=p/x+'0';
p-=(msg[i]-'0')*x;
}
msg[len_sec]=' ';
p=time_ckt.tv_nsec;
int len_nsec=0;
while(p/=10){
len_nsec++;
}
len_nsec++;
if(len_nsec<9){
for(i=0;i<9-len_nsec;i++){
msg[len_sec+1+i]=' ';
}
}
p=time_ckt.tv_nsec;
for(i=0;i<len_nsec;i++){
int x=1;
int j;
for(j=i+1;j<len_nsec;j++){
x*=10;
}
msg[len_sec+1+9-len_nsec+i]=p/x+'0';
p-=(msg[len_sec+1+9-len_nsec+i]-'0')*x;
}
msg[len]='\0';
if(count+has_read>=len){
count=len-has_read;
}
has_read=has_read+count;
copy_to_user(buf, msg, count);
if(count==0)
has_read=0;
return count;
}
struct file_operations proc_fops = {
read: read_proc
};
//装载模块
int proc_init (void) {
msg=(char*)kmalloc(LEN*sizeof(char),GFP_KERNEL);
if(msg==NULL){
printk(KERN_INFO "分配内存失败");
return 0;
}
len=LEN;
has_read=0;
proc_create("clock",0,NULL,&proc_fops);
return 0;
}
//模块卸载
void proc_cleanup(void) {
remove_proc_entry("clock",NULL);
kfree(msg);
msg=NULL;
}
MODULE_LICENSE("GPL");
module_init(proc_init);
module_exit(proc_cleanup);