测试一个进程的运行时间

#include "linux/init.h"
#include "linux/kernel.h"
#include "linux/module.h"  //3个头文件包含了内核提供的所有内核模块的头文件
#include "linux/sched.h"
#include <linux/moduleparam.h>
#include "linux/timer.h"
#include "linux/rtc.h"
#include <linux/kthread.h>
#include <linux/uaccess.h>
#include <linux/string.h>
#include "linux/fs.h"
#include "linux/delay.h"

static int tid = 1;
module_param(tid,int,S_IRUSR);
struct timeval tv;
struct rtc_time tm;
static struct task_struct *myThread=NULL;
static struct task_struct *p=NULL;
static struct task_struct *monitor=NULL;
static int flag_start=0;
static int flag_end=0;
static int start;
static int end;

static int atoi(char a[], int n) {
int ret = a[n-1] - '0';
int i = n - 2;
int carry = 1;
for(;i >= 0; i--) {
carry *= 10;
ret += (a[i] - '0')*carry;
}
return ret;
}

static int get_start_time(void)
{
struct timeval tv2;
struct file *fp;
mm_segment_t fs;
loff_t pos;
char str[10] = {'\0'};
char str2[10] = {0};
int i=0;
int mytime;
fp = filp_open("/proc/uptime", O_RDONLY, 0);
if (IS_ERR(fp)) {
printk("open file error\n");
}
else {
fs = get_fs();
set_fs(KERNEL_DS);
pos = 0;
vfs_read(fp, str, sizeof(str), &pos);
while(str[i] != '.')
{
str2[i]=str[i];
i++;
}
mytime=atoi(str2,strlen(str2));
filp_close(fp, NULL);
set_fs(fs);
do_gettimeofday(&tv2);
rtc_time_to_tm(tv2.tv_sec-mytime+monitor->start_time.tv_sec+8*3600,&tm);
printk("%d-%d-%d %d:%d:%d\n",tm.tm_year+1900,tm.tm_mon+1,tm.tm_mday,tm.tm_hour,tm.tm_min,tm.tm_sec);
return (int)(tv2.tv_sec-mytime+monitor->start_time.tv_sec);
}
}
static int get_end_time(void)
{
do_gettimeofday(&tv);
rtc_time_to_tm(tv.tv_sec+8*3600,&tm);
printk("%d-%d-%d %d:%d:%d\n",tm.tm_year+1900,tm.tm_mon+1,tm.tm_mday,tm.tm_hour,tm.tm_min,tm.tm_sec);
return (int)tv.tv_sec;
}
static void test_thread(void *data)
{
while(!kthread_should_stop())
{
monitor=NULL;
for_each_process(p){
if(p->pid == tid)
{
monitor=p;
if(flag_start == 0)
{
printk("start time:");
start=get_start_time();
flag_start=1;
}
break;
}
}
if(monitor == NULL)
{
if(flag_end == 0)
{
printk("stop time:");
end=get_end_time();
flag_end=1;
printk("thread %d is last for %d seconds\n",tid,end-start);
}
}
msleep(10);
}
}
static int __init test_thread_init(void) {
myThread=kthread_run(test_thread,NULL,"mythread");
return 0;
}

static void __exit test_thread_exit(void) {
if(myThread)
{
printk("stop thread\n");
kthread_stop(myThread);
}
}

module_init(test_thread_init);  //告诉内核当内核模块第一次运行时哪个函数将被执行
module_exit(test_thread_exit); //内核模块被卸载时被执行的函数
MODULE_LICENSE("GPL");  //开源license

obj-m := test_thread.o
KERNELBUILD := /lib/modules/$(shell uname -r)/build
default:
make -C $(KERNELBUILD) M=$(shell pwd) modules
clean:
rm -rf *.o *.ko *.mod.c .*.cmd *.markers *.order *.symvers .tmp_versions