#define _GNU_SOURCE             /* See feature_test_macros(7) */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/xattr.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <errno.h>
#include <string.h>
#include <linux/reboot.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <grp.h>
#include <sys/prctl.h>
#include <linux/fs.h>
#include <signal.h>
#include <sched.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include <sys/sysinfo.h>
#include <sys/epoll.h>
#include <asm/unistd.h>
#include <sys/time.h>

struct ubi_set_vol_prop_req {
	uint8_t  property;
	uint8_t  padding[7];
	uint64_t value;
} __attribute__((packed));

#define UBI_VOL_IOC_MAGIC 'O'
#define UBI_VOL_PROP_DIRECT_WRITE 1
#define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, struct ubi_set_vol_prop_req)

void setup(void)
{
	system("modprobe -r ubi 2>/dev/null");
	system("modprobe -r nandsim 2>/dev/null || true");
	system("modprobe nandsim id_bytes=0xec,0xa1,0x00,0x15 # 128M 128KB 2KB");
	system("modprobe ubi mtd=0,2048 fm_autoconvert");
	system("ubimkvol -N vol_a -S 990 -n 0 /dev/ubi0");
}

int get_leb_info(int *cnt, int *leb_size)
{
	char buf[100];
	int fd = open("/sys/class/ubi/ubi0_0/reserved_ebs", O_RDONLY);
	if (fd < 0) {
		perror("cannot open reserved_ebs");
		return -1;
	}
	if (read(fd, buf, 10) < 0) {
		perror("cannot read reserved_ebs");
		return -1;
	}
	sscanf(buf, "%d", cnt);
	close(fd);

	fd = open("/sys/class/ubi/ubi0_0/usable_eb_size", O_RDONLY);
	if (fd < 0) {
		perror("cannot open usable_eb_size");
		return -1;
	}
	if (read(fd, buf, 10) < 0) {
		perror("cannot read usable_eb_size");
		return -1;
	}
	sscanf(buf, "%d", leb_size);
	close(fd);

	return 0;
}

int main(void)
{
	int i, fd, cnt, leb_size;
	char buf[4096];
	struct ubi_set_vol_prop_req r;

	setup();
	if (get_leb_info(&cnt, &leb_size) < 0)
		return 0;

	fd = open("/dev/ubi0_0", O_RDWR);
	if (fd < 0) {
		perror("cannot open ubi");
		return 0;
	}

	memset(&r, 0, sizeof(struct ubi_set_vol_prop_req));
	r.property = UBI_VOL_PROP_DIRECT_WRITE;
	r.value = 1;
	if (ioctl(fd, UBI_IOCSETVOLPROP, &r) < 0) {
		perror("ioctl fail");
		return 0;
	}

	for (i = 0; i < cnt; ++i) {
		if (lseek(fd, i * leb_size, SEEK_SET) != i * leb_size) {
			perror("seek fail");
			return 0;
		}
		if (write(fd, buf, 4096) < 0) {
			perror("write fail");
			return 0;
		}
	}

	close(fd);
	return 0;
}