syslog.c

在一本书上看到的 守护进程的日志实现 程序是课本的讲解例题 拿过来跟大家分享一下。。。

#include<stdio.h>
#include<syslog.h>
#include<stdlib.h>
#include<string.h>
#include<fcntl.h>
#include<sys/types.h>
#include<unistd.h>
#include<sys/wait.h>
#define MAXFILE 65535
int main()
{
	pid_t pc,sid;
	int i,fd,len;
	char *buf="this is a dameon\n";
	len=strlen(buf);
	pc=fork();
	if(pc<0){
	printf("error fork\n");
	exit(1);
	}else if(pc>0)
	exit(0);
/*打开系统日志服务,openlog*/
	openlog("demo_update",LOG_PID,LOG_DAEMON);
	if((sid=setsid())<0){
	syslog(LOG_ERR,"%s\n","setsid");
	exit(1);
	}
	if((sid=chdir("/"))<0){
	syslog(LOG_ERR,"%s\n","chdir");
	exit(1);
	}
	umask(0);
	for(i=0;i<MAXFILE;i++)
	close(i);
	while(1){
/*打开守护进程的日志文件，写入open的日志文件*/
	if((fd=open("/tmp/dameon.log",O_CREAT|O_WRONLY|O_APPEND,0600))<0){
	syslog(LOG_ERR,"open");
	exit(1);
	}
	write(fd,buf,len+1);
	close(fd);
	sleep(10);
	}
	closelog();
	exit(0);
}