int stat(const char *path, struct stat *sb);
     struct stat {
         dev_t    st_dev;    /* device inode resides on */
         ino_t    st_ino;    /* inode's number */
         mode_t   st_mode;   /* inode protection mode */
         nlink_t  st_nlink;  /* number or hard links to the file */
         uid_t    st_uid;    /* user-id of owner */
         gid_t    st_gid;    /* group-id of owner */
         dev_t    st_rdev;   /* device type, for special file inode */
         struct timespec st_atimespec;  /* time of last access */
         struct timespec st_mtimespec;  /* time of last data modification */
         struct timespec st_ctimespec;  /* time of last file status change */
         off_t    st_size;   /* file size, in bytes */
         quad_t   st_blocks; /* blocks allocated for file */
         u_long   st_blksize;/* optimal file sys I/O ops blocksize */
         u_long   st_flags;  /* user defined flags for file */
         u_long   st_gen;    /* file generation number */
     };

DIR *opendir(const char *filename);
struct dirent * readdir(DIR *dirp);

struct dirent {
        u_int32_t d_fileno;             /* file number of entry */
        u_int16_t d_reclen;             /* length of this record */
        u_int8_t  d_type;               /* file type, see below */
        u_int8_t  d_namlen;             /* length of string in d_name */
        char    d_name[MAXNAMLEN + 1];  /* name must be no longer than this */
};