nrdmn

vsock notes

about vsocks

Vsocks are a means of providing socket communication (either stream or datagram) directly between VMs and their host operating system. The host and each VM have a 32 bit CID (Context IDentifier) and may connect or bind to a 32 bit port number. Ports < 1024 are privileged ports.

• Vsock communication between VMs does not seem to work.
• Only one vsock device per VM is supported.

nrdmn

/etc/localtime:
ln -sf /usr/share/zoneinfo/Europe/Berlin /etc/localtime


/etc/rc.conf:
inetd=NO
postfix=NO
named=YES

nrdmn

#!/usr/bin/python3
# reads a list of IP subnets in CIDR notation from stdin and collapses it

import sys
import ipaddress

subnets6 = []
subnets4 = []

input_list = sys.stdin.readlines()

nrdmn

.equ PORTB, 5

; void ws2812(const char *ptr, const size_t n);

.global ws2812
ws2812:
	; Move ptr (r24, r25) to X (r26, r27)
	movw X, r24
	; Move n (r22, r23) to r24, r25
	movw r24, r22

nrdmn

#define _GNU_SOURCE
#include <dlfcn.h>
#include <fcntl.h>

int fcntl(int fd, int cmd, ...)
{
	if (cmd == F_OFD_SETLKW || cmd == F_OFD_SETLK) {
		return 0;
	}
	int (*orig)(int, int, ...) = dlsym(RTLD_NEXT, "fcntl");

nrdmn

#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <stdbool.h>
#include <ctype.h>

void unescape(char *buf)

nrdmn

U-Boot 2009.08 (Sep 27 2011 - 09:33:22)

CPU:   Freescale i.MX50 family 1.1V at 800 MHz
mx50 pll1: 800MHz
mx50 pll2: 400MHz
mx50 pll3: 216MHz
ipg clock     : 66666666Hz
ipg per clock : 66666666Hz

nrdmn

/**
 * Apply a function which produces an array to all of an array's elements and concatenate the results.
 *
 * @param callable $func The function to be applied to every of $arr's elements to produce a new array each.
 * @param array $arr
 * @return array
 */
function array_flatmap(callable $func, array $arr) : array
{
    return array_merge([], ...array_map($func, $arr));

nrdmn

const std = @import("std");

fn Add(comptime A: type, comptime B: type) type {
    if (A == type) {
        return B;
    } else {
        return Add(@typeInfo(A).Pointer.child, *B);
    }
}

nrdmn

import System.Environment (getArgs)
import System.IO (hPutStrLn, stderr)
import Data.List (genericTake)
import Text.Read (readMaybe)

-- sqrt possibly inaccurate for large primes.
primes = 2 : [ n | n<-[3,5..], all (\x -> n `mod` x /= 0) $ takeWhile (<= (floor $ sqrt $ fromIntegral n)) primes]
-- guaranteed to be correct for all primes, but much slower:
-- primes = 2 : [ n | n<-[3,5..], all (\x -> n `mod` x /= 0) $ takeWhile (<= (quot n 2)) primes]
-- for all n out of [1..] there's a prime p so that n < p < 2*n (Bertrand's postulate)