#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>

int main(void) {
	char buff[0x40000];
	long size;
	int fd;
	struct stat st;

	fd = open("test.bin",O_RDWR|O_TRUNC|O_CREAT,0666);
	if (fd<0) {
		perror("open");
		return 1;
	}
	while (1) {
		size = random()&0x3FFFF;
		switch (random()%3) {
			case 0:
				ftruncate(fd,size);
				break;
			case 1:
				lseek(fd,0,SEEK_SET);
				write(fd,buff,size);
				break;
			case 2:
				lseek(fd,0,SEEK_SET);
				read(fd,buff,size);
				break;
		}
	}
	return 0;
}