Pierre Cashon biaocy

轻松学习汇编语言

汇编是直接跟硬件打交道的，于是在学习汇编的同时，不经意间就了解到计算机的工作原理。

《穿越计算机的迷雾 by 李忠》

这是饭前开胃菜，作者从什么是电流开始，讲加法器、数字逻辑、触发器、CPU 原理、外设等，是计算机（硬件）组成原理的科普向轻松读物

《汇编语言 by 王爽》

init.rc changes

init.rc changes to run any script Can be used to start any android application, service

on property:dev.bootcomplete=1
    exec - system system -- /system/bin/sh <custom script path>
    # exec - system system -- /system/bin/sh /data/local/bootscript/testservice.sh

Script can contains applications start, stop commands

Handle CORS Client-side

Cross-origin resource sharing (CORS) is a mechanism that allows restricted resources (e.g. fonts) on a web page to be requested from another domain outside the domain from which the first resource was served. This is set on the server-side and there is nothing you can do from the client-side to change that setting, that is up to the server/API. There are some ways to get around it tho.

Sources : MDN - HTTP Access Control | Wiki - CORS

CORS is set server-side by supplying each request with additional headers which allow requests to be requested outside of the own domain, for example to your localhost. This is primarily set by the header:

Access-Control-Allow-Origin

Direct copy of pre-encoded file:

$ ffmpeg -i filename.mp4 -codec: copy -start_number 0 -hls_time 10 -hls_list_size 0 -f hls filename.m3u8

Safest way to clean up boot partition - Ubuntu 14.04LTS-x64, Ubuntu 16.04LTS-x64

Reference

Case I: if /boot is not 100% full and apt is working

1. Check the current kernel version

$ uname -r

	{
	"key_events": {
	"key_unknown": "adb shell input keyevent 0",
	"key_soft_left": "adb shell input keyevent 1",
	"key_soft_right": "adb shell input keyevent 2",
	"key_home": "adb shell input keyevent 3",
	"key_back": "adb shell input keyevent 4",
	"key_call": "adb shell input keyevent 5",
	"key_endcall": "adb shell input keyevent 6",
	"key_0": "adb shell input keyevent 7",

	const drawille = require('drawille')
	const bunny = require('bunny')
	const glmatrix = require('gl-matrix')
	const width = 200
	const height = 200
	const canvas = new drawille(width, height)
	const mat4 = glmatrix.mat4
	const vec3 = glmatrix.vec3

	let points = []

	class FullscreenOverlayService extends Service {

	private View overlay;
	private WindowManager windowManager;

	@Nullable
	@Override
	public IBinder onBind(Intent intent) {
	return null;
	}

	/**
	* To get started install
	* express bodyparser jsonwebtoken express-jwt
	* via npm
	* command :-
	* npm install express body-parser jsonwebtoken express-jwt --save
	*/

	// Bringing all the dependencies in
	const express = require('express');

	### 1: Drop invalid packets ###
	/sbin/iptables -t mangle -A PREROUTING -m conntrack --ctstate INVALID -j DROP

	### 2: Drop TCP packets that are new and are not SYN ###
	/sbin/iptables -t mangle -A PREROUTING -p tcp ! --syn -m conntrack --ctstate NEW -j DROP

	### 3: Drop SYN packets with suspicious MSS value ###
	/sbin/iptables -t mangle -A PREROUTING -p tcp -m conntrack --ctstate NEW -m tcpmss ! --mss 536:65535 -j DROP

	### 4: Block packets with bogus TCP flags ###