Aus der fstat-Manpage:

fstat(2),Linux

      S_IFMT     0170000   bitmask for the file type bitfields
      S_IFSOCK   0140000   socket
      S_IFLNK    0120000   symbolic link
      S_IFREG    0100000   regular file
      S_IFBLK    0060000   block device
      S_IFDIR    0040000   directory
      S_IFCHR    0020000   character device
      S_IFIFO    0010000   fifo
      S_ISUID    0004000   set UID bit
      S_ISGID    0002000   set GID bit (see below)
      S_ISVTX    0001000   sticky bit (see below)
      S_IRWXU    00700     mask for file owner permissions
      S_IRUSR    00400     owner has read permission
      S_IWUSR    00200     owner has write permission
      S_IXUSR    00100     owner has execute permission
      S_IRWXG    00070     mask for group permissions
      S_IRGRP    00040     group has read permission
      S_IWGRP    00020     group has write permission
      S_IXGRP    00010     group has execute permission
      S_IRWXO    00007     mask for permissions for others (not in group)
      S_IROTH    00004     others have read permission
      S_IWOTH    00002     others have write permisson
      S_IXOTH    00001     others have execute permission