capng_get_caps_fd - read file-based capabilities from extended attributes
int capng_get_caps_fd(int fd);
This function will read the file based capabilities stored in extended
attributes of the file that the descriptor was opened against. The bounding
set is not included in file based capabilities operations. Note that this
function will only work if compiled on a kernel that supports file based
capabilities such as 2.6.26 and later. If the "magic" bit is set,
then all effect capability bits are set. Otherwise the bits are cleared.
This returns 0 on success and -1 on failure.