C IO programming test code

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#define BUFLEN 255

#define ERR_EXIT(m) \
	do \
    { \
		perror(m); \
		exit(EXIT_FAILURE); \
	} while(0)


int main(){
	int fd;
	int fd_log;
	char *buf01="open /dev/urandom success\n";
	char *buf02="open /dev/urandom failed\n";
	char dest[100];
	int size;
	int max=604800;//7days
	int i=0;
	time_t timep;
	char tmpBuf[BUFLEN];

	umask(0);
	fd_log = open("/var/log/test_urandom.log",O_CREAT|O_APPEND|O_RDWR,0666);
	if (fd_log == -1){
		ERR_EXIT("open error");
	}else{
		printf("open /var/log/test_urandom.log success");
	}

	while(i < max){
		fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);

		//now
		time(&timep);
		strcpy(tmpBuf,ctime(&timep));

		//failed
		if (fd < 0){
			strcpy(dest,tmpBuf);
			strcat(dest,":");
			strcat(dest,buf02);
			if((size=write(fd_log,dest,strlen(dest))) < 0){
				perror("write failed");
			}
		}else{ //success
			strcpy(dest,tmpBuf);
			strcat(dest,":");
			strcat(dest,buf01);
			if ((size=write(fd_log,dest,strlen(dest))) < 0){
				perror("write failed");
			}
		}
		close(fd);
		sleep(1);
		i+=1;
	}
		close(fd_log);

	return 0;
}