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# references:
#   Learning by doing: Writing your own traceroute in 8 easy steps (Ksplice Blog)
#   https://blogs.oracle.com/ksplice/entry/learning_by_doing_writing_your

# Edited by: Alejandro Almira <laboral at alejandroalmira.com>

import datetime
import socket
import sys

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Symmetic encryption

For symmetic encryption, you can use the following:

To encrypt:

openssl aes-256-cbc -salt -a -e -in plaintext.txt -out encrypted.txt

To decrypt:

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## Common

````
export OPT=/opt
export BUILDS=/some/where/mini_linux
mkdir -p $BUILDS
````

## Linux kernel

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ELF Format Cheatsheet

Introduction

Executable and Linkable Format (ELF), is the default binary format on Linux-based systems.

Compilation

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

#include <netinet/tcp.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>

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#include <stdio.h>  /* fprintf() */
#include <stdlib.h> /* exit() */
#include <sys/types.h>  /* socket(), wait4() */
#include <sys/socket.h>	/* socket() */
#include <netinet/in.h>	/* struct sockaddr_in */
#include <sys/resource.h> /* wait4() */
#include <sys/wait.h>	/* wait4() */
#include <pthread.h>	/* pthread_create */
#include <netdb.h>	/* getnameinfo() */
#include <string.h>	/* strlen() */

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/* Compile with: g++ -Wall –Werror -o shell shell.c */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
 
#include <sys/types.h>
#include <sys/wait.h>

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import urllib
import shutil
import re
from pathlib import Path
from bs4 import BeautifulSoup

# target page containing links to the image files
target_page = 'http://example.ca/image_links.php'

# local path

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#include <stdio.h>

void DumpHex(const void* data, size_t size) {
	char ascii[17];
	size_t i, j;
	ascii[16] = '\0';
	for (i = 0; i < size; ++i) {
		printf("%02X ", ((unsigned char*)data)[i]);
		if (((unsigned char*)data)[i] >= ' ' && ((unsigned char*)data)[i] <= '~') {
			ascii[i % 16] = ((unsigned char*)data)[i];

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Introduced in musl v1.2.1. Design goal: "Strong hardening against memory usage errors by the caller, including detection of overflows, double-free, and use-after-free, and does not admit corruption of allocator state via these errors."

context

// Singleton: ctx
struct malloc_context {
  uint64_t secret;
#ifndef PAGESIZE
  size_t pagesize;