[Linux]守护进程

/**
 @ 守护进程
 @ 2015-3-12
 */
#include <stdio.h>
#include <signal.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#include <fcntl.h>

volatile sig_atomic_t _running = 1;
void sigterm_handler(int arg);

int main()
{
	pid_t pc, pid;
	char *buf = "hello world";
	pc = fork();
	if (pc < 0)
	{
		printf("error..\n");
		exit(0);
	}
	else if (pc > 0)
		exit(0);
	
	pid = setsid();
	if (pid < 0)
		perror("setsid is error\n");
	
	chdir("/");
	umask(0);
	
	int i = 0;
	for (; i < NOFILE; ++ i)
		close(i);	
	
	signal(SIGTERM, sigterm_handler);	
	
	int flag;
	flag = 1;
	int fd;	
	while (_running)
	{
		fd = open("/tmp/mytest.log", O_CREAT|O_WRONLY|O_APPEND,0600) < 0;
		if (flag && fd < 0)
		{
			printf("open file..\n");
			flag = 0;
			exit(1);
		}
		
		write(fd, buf, strlen(buf));
		close(fd);
		usleep(10 * 1000);
	}
	return 0;
}

void sigterm_handler(int arg)
{
	_running = 0;
}

一个在后台运行的进程例子（守护进程）