kconner

macOS Internals

Understand your Mac and iPhone more deeply by tracing the evolution of Mac OS X from prelease to Swift. John Siracusa delivers the details.

Starting Points

How to use this gist

You've got two main options:

0x36

#if 0
IOAccelContext2::finish_fence_event() race condition OOB read/write

This is a method exposed to user space, it takes a kernel read-only shared memory
(type 2 via clientMemoryForType())  address and treats it as an IOAccelEvents Array.

The user supplied index is checked against the IOAccelEvents array bounds,since there are no
locks held in this method,it is possible to change the array bounds by calling
IOAccelContext2::clientMemoryForType() again in a separate thread, this will expand the size by
multiplying the older size by 2, but we still have a reference to the old shared memory address

cb372

(This is a translation of the original article in Japanese by moratorium08.)

(UPDATE (22/3/2019): Added some corrections provided by the original author.)

Writing your own OS to run on a handmade CPU is a pretty ambitious project, but I've managed to get it working pretty well so I'm going to write some notes about how I did it.

anatol

https://medium.com/@clem.boin/creating-a-minimal-kernel-development-setup-using-qemu-and-archlinux-987896954d84

# Install Arch system
qemu-image -f qcow2 kernel-dev-archlinux.img 4G
wget http://mirrors.edge.kernel.org/archlinux/iso/2018.12.01/archlinux-2018.12.01-x86_64.iso
# Note that ping does not work here
qemu-system-x86_64 -cdrom archlinux-2018.12.01-x86_64.iso -boot order=d -drive file=kernel-dev-archlinux.img,format=qcow2 -m 2G -enable-kvm -cpu host -smp 8 -net user,hostfwd=tcp::10022-:22 -net nic

jackyyf

#!/bin/bash -e
# 
# wireguard helper script
#

IP=/sbin/ip

if [ "$IF_WG_CONF" -o "$IF_WG_PRIVATE_KEY" ]
then
	$IP link del $IFACE

extremecoders-re

Setting up Qemu with a tap interface

There are two parts to networking within QEMU:

• The virtual network device that is provided to the guest (e.g. a PCI network card).
• The network backend that interacts with the emulated NIC (e.g. puts packets onto the host's network).

Example: User mode network

chrisdone

Common

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

Linux kernel

tonyseek

#!/usr/bin/env sh

## I don't have any devices running Android OS now. These settings may have been outdated but I cannot verify it.

adb shell settings put global captive_portal_fallback_url http://g.cn/generate_204
adb shell settings put global captive_portal_http_url http://www.google.cn/generate_204
adb shell settings put global captive_portal_https_url https://www.google.cn/generate_204
adb shell settings put global captive_portal_other_fallback_urls http://www.qualcomm.cn/generate_204

arfon

How many times shouldn't it happen...

-- https://news.ycombinator.com/item?id=11396045

SELECT count(*)
FROM (SELECT id, repo_name, path
        FROM [bigquery-public-data:github_repos.sample_files]
 ) AS F

LeCoupa

// XPath CheatSheet
// To test XPath in your Chrome Debugger: $x('/html/body')
// http://www.jittuu.com/2012/2/14/Testing-XPath-In-Chrome/


// 0. XPath Examples.
// More: http://xpath.alephzarro.com/content/cheatsheet.html


'//hr[@class="edge" and position()=1]'                // every first hr of 'edge' class