crazyguitar

" python file template "
au BufNewFile *.py 0r ~/.vim/templates/template.py

" Makefile template "
au BufNewFile Makefile,makefile 0r ~/.vim/templates/Makefile.temp

" c template "
au BufNewFile *.c 0r ~/.vim/templates/c.temp     

" folding *.h comment"

crazyguitar

When you cancel a Jenkins job

Unfinished draft; do not use until this notice is removed.

We were seeing some unexpected behavior in the processes that Jenkins launches when the Jenkins user clicks "cancel" on their job. Unexpected behaviors like:

• apparently stale lockfiles and pidfiles
• overlapping processes
• jobs apparently ending without performing cleanup tasks
• jobs continuing to run after being reported "aborted"

crazyguitar

Running Docker on two hosts, bridged with Open vSwitch

This Gist shows how to use Open vSwitch to bridge Docker containers on two hosts. It is based on this blog post http://goldmann.pl/blog/2014/01/21/connecting-docker-containers-on-multiple-hosts/.

A similar Gist using Tinc instead of Open vSwitch is available: https://gist.github.com/noteed/11031504.

Setup

crazyguitar

/*
 * A sample program of KCM.
 *
 * $ gcc -lbcc kcm-sample.c
 * $ ./a.out 10000
 */
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

crazyguitar

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <err.h>

#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>

crazyguitar

obj-m += tcp_svr_sample.o
 
all:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
 
clean:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clea

crazyguitar

1. Execute make first. This will result in a netlinkKernel.ko output among many others.
2. Execute $ gcc netlinkUser.c -o netlinkUser
3. Insert kernel module by :$ sudo insmod netlinkKernel.ko      
4. Run ./netlinkUser to see message and run dmesg to see debug messages
5. Remove module by : $ sudo rmmod netlinkKernel          
6. Finally make clean to remove output files.

crazyguitar

package main

import (
	"fmt"
	"net"
	"os"
	"syscall"
)

const (

crazyguitar

# Basics of Elliptic Curve Cryptography implementation on Python
import collections


def inv(n, q):
    """div on PN modulo a/b mod q as a * inv(b, q) mod q
    >>> assert n * inv(n, q) % q == 1
    """
    for i in range(q):
        if (n * i) % q == 1:

crazyguitar

Domain Name Server (DNS)

Concept

1. Two type of DNS network activities:
   1. lookup: DNS client queries a DNS server for information
   2. zone transfers: DNS server (the secondary server) requests from another DNS server (the primary server)
2. DNS lookups are usualy executed usin UDP. (If some of data is lost in transit by UDP, the lookup will be redone using TCP)
3. DNS sever uses well-known port 53 (UDP/TCP)
4. Proxying characteristics of DNS: