#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>

int main(int argc, char **argv)
{
    const char *path = "/zvfs/func_test.dat";

    printf("open: %s\n", path);
    int fd = open(path, O_CREAT | O_RDWR | O_TRUNC, 0644);
    if (fd < 0) { perror("open"); return 1; }

    const char *msg = "ABCDEFGHIJKL";
    ssize_t w = write(fd, msg, strlen(msg));
    if (w < 0) { perror("write"); return 2; }
    printf("write: %zd\n", w);

    const char *msg2 = "MNOPQRSTUVWXYZ";
    ssize_t w2 = write(fd, msg2, strlen(msg2));
    if (w2 < 0) { perror("write"); return 2; }
    printf("write: %zd\n", w2);

    close(fd);


    fd = open(path, O_RDONLY);
    if (fd < 0) { perror("open R"); return 3; }

    char buf[10];
    memset(buf, 0, sizeof(buf));
    ssize_t r = read(fd, buf, sizeof(buf));
    if (r < 0) { perror("read"); return 4; }
    printf("read: %zd bytes: %.*s\n", r, (int)r, buf);

    char buf2[512];
    memset(buf2, 0, sizeof(buf2));
    ssize_t r2 = read(fd, buf2, sizeof(buf2));
    if (r2 < 0) { perror("read"); return 4; }
    printf("read: %zd bytes: %.*s\n", r2, (int)r2, buf2);

    close(fd);

    if (unlink(path) != 0) { perror("unlink"); return 5; }
    printf("unlink: ok\n");
    return 0;
}