Webserver(2.8)守护进程
#include<stdio.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<unistd.h>
#include<fcntl.h>
#include<sys/time.h>
#include<signal.h>
#include<time.h>
#include<stdlib.h>
#include<string.h>
void work(int num){
//捕捉到信号之后,获取系统时间，写入磁盘文件
time_t tm=time(NULL);
struct tm * loc=localtime(&tm);
// char buf[1024];
// sprintf(buf,"%d-%d-%d %d:%d:%d\n",loc->tm_year,
// loc->tm_mon,loc->tm_mday,loc->tm_hour,loc->tm_min,loc->tm_sec);
//printf("%s\n",buf);
char * str =asctime(loc);
int fd=open("time.txt",O_RDWR|O_CREAT|O_APPEND,0664);
write(fd,str,strlen(str));
close(fd);
}
int main(){
//1.创建子进程，退出父进程
pid_t pid=fork();
if(pid>0){
exit(0);
}
//2.将子进程提升为会话
setsid();
//3.设置掩码
umask(022);
//4.更改工作目录
chdir("/home/nowcoder/");
//5.关闭、重定向文件描述符
int fd=open("/dev/null",O_RDWR);
dup2(fd,STDIN_FILENO);
dup2(fd,STDOUT_FILENO);
dup2(fd,STDERR_FILENO);
//6.业务逻辑
struct sigaction act;
act.sa_flags=0;
act.sa_handler=work;
sigemptyset(&act.sa_mask);
sigaction(SIGALRM,&act,NULL);
//捕捉定时信号
struct itimerval val;
val.it_value.tv_sec=2;
val.it_value.tv_usec=0;
val.it_interval.tv_sec=2;
val.it_interval.tv_usec=0;
//创建定时器
setitimer(ITIMER_REAL,&val,NULL);
//不让进程结束
while(1){
sleep(10);
}
return 0;
}