Function capability_is_in_bounding_set

src/thread/prctl.rs:467–476

(capability: impl CompatCapability)

/// [`prctl(PR_CAPBSET_READ,…)`]: https://man7.org/linux/man-pages/man2/prctl.2.html
#[inline]
pub fn capability_is_in_bounding_set(capability: impl CompatCapability) -> io::Result<bool> {
    let capset = capability.as_capability_set(private::Token).bits();
    if capset.count_ones() != 1 {
        return Err(Errno::INVAL);
    }
    let cap = capset.trailing_zeros();

    // as *mut _ should be ptr::without_provenance_mut but our MSRV does not allow it.
    unsafe { prctl_2args(PR_CAPBSET_READ, cap as usize as *mut _) }.map(|r| r != 0)
}

const PR_CAPBSET_DROP: c_int = 24;