Function capability_is_in_ambient_set

src/thread/prctl.rs:698–714

(capability: impl CompatCapability)

/// [`prctl(PR_CAP_AMBIENT,PR_CAP_AMBIENT_IS_SET,…)`]: https://man7.org/linux/man-pages/man2/prctl.2.html
#[inline]
pub fn capability_is_in_ambient_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();

    unsafe {
        prctl_3args(
            PR_CAP_AMBIENT,
            PR_CAP_AMBIENT_IS_SET as *mut _,
            // as *mut _ should be ptr::without_provenance_mut but our MSRV does not allow it.
            cap as usize as *mut _,
        )
    }
    .map(|r| r != 0)
}

const PR_CAP_AMBIENT_CLEAR_ALL: usize = 4;