#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <dirent.h>

#include <errno.h>

#include <sys/stat.h>

#include "../internal/malloc.h"
#include "../internal/syscall.h"
#include "dirent_impl.h"

/*
 * fdopendir (todo 24): validate the descriptor with SYS_fstat (POSIX
 * requires the fd to name a directory), then allocate the stream state.
 * On failure the descriptor is NOT closed — it stays owned by the caller,
 * exactly as passed in.
 */
DIR *
fdopendir(int fd)
{
    struct stat st;
    DIR *d;

    if (syscall_ret(__syscall2(SYS_fstat, fd, (long)&st)) < 0)
    {
        return NULL;
    }
    if (!S_ISDIR(st.st_mode))
    {
        errno = ENOTDIR;
        return NULL;
    }
    d = __libc_malloc(sizeof *d);
    if (d == NULL)
    {
        errno = ENOMEM;
        return NULL;
    }
    d->fd = fd;
    d->buf_pos = 0;
    d->buf_end = 0;
    d->de.d_off = 0;
    return d;
}