socketcan-hal 2.0.0

use libc::{c_int, c_void, setsockopt, socklen_t, timespec};
use std::{io, ptr};
use std::mem::size_of;
use std::time::{Duration, SystemTime, UNIX_EPOCH};


/// `setsockopt` wrapper
///
/// The libc `setsockopt` function is set to set various options on a socket.
/// `set_socket_option` offers a somewhat type-safe wrapper that does not
/// require messing around with `*const c_void`s.
///
/// A proper `std::io::Error` will be returned on failure.
///
/// Example use:
///
/// ```text
/// let fd = ...;  // some file descriptor, this will be stdout
/// set_socket_option(fd, SOL_TCP, TCP_NO_DELAY, 1 as c_int)
/// ```
///
/// Note that the `val` parameter must be specified correctly; if an option
/// expects an integer, it is advisable to pass in a `c_int`, not the default
/// of `i32`.
#[inline]
pub fn set_socket_option<T>(fd: c_int, level: c_int, name: c_int, val: &T) -> io::Result<()> {
    let rv = unsafe {
        let val_ptr: *const T = val as *const T;

        setsockopt(fd,
                   level,
                   name,
                   val_ptr as *const c_void,
                   size_of::<T>() as socklen_t)
    };

    if rv != 0 {
        return Err(io::Error::last_os_error());
    }

    Ok(())
}

pub fn set_socket_option_mult<T>(fd: c_int,
                                 level: c_int,
                                 name: c_int,
                                 values: &[T])
                                 -> io::Result<()> {

    let rv = if values.is_empty() {
        // can't pass in a pointer to the first element if a 0-length slice,
        // pass a nullpointer instead
        unsafe { setsockopt(fd, level, name, ptr::null(), 0) }
    } else {
        unsafe {
            let val_ptr = &values[0] as *const T;

            setsockopt(fd,
                       level,
                       name,
                       val_ptr as *const c_void,
                       (size_of::<T>() * values.len()) as socklen_t)
        }
    };

    if rv != 0 {
        return Err(io::Error::last_os_error());
    }

    Ok(())
}

#[inline]
pub fn duration_from_timeval(ts: timespec) -> Duration {
    Duration::new(ts.tv_sec as u64, ts.tv_nsec as u32)
}

#[inline]
pub fn system_time_from_timespec(ts: timespec) -> SystemTime {
    UNIX_EPOCH + duration_from_timeval(ts)
}