testdae.c

守护进程的创建方法,供各位网友参考

#include <stdio.h>
#include <time.h> 
#include <signal.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
int init_daemon(void)//守护进程初始化函数 
{
switch(fork()){
case 0:break;
case -1:return -1;
deault:_exit(0);
}
if (setsid()<0) return -1;
signal(SIGHUP,SIG_IGN);
switch(fork()){
 case 0:break;
 case -1:return(-1);
 default:_exit(0);
}
chdir("/");
umask(0);
int fdlimit=sysconf(_SC_OPEN_MAX);
int fd=0;
FILE *fp;
time_t t;
while (fd<fdlimit){
 close(fd);
 fd++;
}
open("/dev/null",O_RDWR);
dup(0);
dup(0);
while(1)//每隔一分钟向test.log报告运行状态
{
syslog(LOG_ERR|LOG_LOCAL0,"OK");
sleep(5);//睡眠一分钟
if((fp=fopen("test.log","a")) >=0)
{
t=time(0);
fprintf(fp,"I'm here at %s\n",asctime(localtime(&t)) );
fclose(fp);
}
}
}
main() 
{ 
init_daemon();//初始化为Daemon 
printf("ok:");
}