Function configure_capability_in_ambient_set

src/thread/prctl.rs:739–763

(
    capability: impl CompatCapability,
    enable: bool,
)

/// [`prctl(PR_CAP_AMBIENT,…)`]: https://man7.org/linux/man-pages/man2/prctl.2.html
#[inline]
pub fn configure_capability_in_ambient_set(
    capability: impl CompatCapability,
    enable: bool,
) -> io::Result<()> {
    let sub_operation = if enable {
        PR_CAP_AMBIENT_RAISE
    } else {
        PR_CAP_AMBIENT_LOWER
    };
    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,
            sub_operation as *mut _,
            // as *mut _ should be ptr::without_provenance_mut but our MSRV does not allow it.
            cap as usize as *mut _,
        )
    }
    .map(|_r| ())
}

//
// PR_SVE_GET_VL/PR_SVE_SET_VL