用c实现进程监控，如果某一进程退出则重启

#include 
#include 
#include 
#include 
#include 
#include 
#include   
#include 
#include 
#include 



//要监控的程序
#define P1 "hello1"
#define P2 "hello2"
#define P3 "hello3"
#define PATH "."

/*****************************/
int is_run(char *name);
void killall_hello(void);
/*****************************/


//运行返回1，没有运行返回0
int is_run(char *name)
{
    int ret = -1;
    char buf[256] = {'\0'};
    snprintf(buf, sizeof(buf), "pidof %s >> /dev/null", name); 
    ret = system(buf);

    if(!WEXITSTATUS(ret)){ //#include 
        printf("%s is running!\n", name);
        return 1;
    }
    else{
        printf("%s is not running!\n", name);
        return 0;
    }
}

void killall_hello(void)
{ 
    char buf[128] = {'\0'};
    snprintf(buf, sizeof(buf), "killall %s", P1);
    system(buf);
    snprintf(buf, sizeof(buf), "killall %s", P2);
    system(buf);
    snprintf(buf, sizeof(buf), "killall %s", P3);
    system(buf);

}


int main(int argc, char **argv)
{
    int p1_ret = -1;
    int p2_ret = -1;
    int p3_ret = -1;
    char buf[128];
    bzero(buf, sizeof(buf));


    while(1){

    p1_ret = is_run(P1);
    p2_ret = is_run(P2);
    p3_ret = is_run(P3);

    if (!(p1_ret && p2_ret && p3_ret))
    {
        killall_hello(); 
        printf("rerun hello3\n");
        snprintf(buf, sizeof(buf), "%s/%s &", PATH, P3);
        system(buf);

    //打印日志信息
    system("date >> w.log");
    if(!p1_ret){
        snprintf(buf, sizeof(buf), "echo %s not run , killall , run %s >> w.log", P1, P3);
        system(buf);
    }else if(!p2_ret){
        snprintf(buf, sizeof(buf), "echo %s not run , killall , run %s >> w.log", P2, P3);
        system(buf);
    }else if(!p3_ret){
        snprintf(buf, sizeof(buf), "echo %s not run , killall , run %s >> w.log", P3, P3);
        system(buf);
            }
        }
    sleep(5);
    }
    exit(0);
}