raspi-boot.sh

#!/bin/bash      
#title...........:raspi-boot.sh
#description.....:Set up bridged network and launch raspberry pi image
#author..........:scott@bitwise.ninja
#date............:2015.07.20
#version.........:0.5    
#usage...........:sudo bash raspi-boot.sh <usernmae>
#notes...........:none
#==============================================================================

## get raspbian image file name
pi_img=$(ls -t *.img | head -1 )

## create TAP as this user
run_user=$1
## find the host's gateway
gw=$(/sbin/ip route | awk '/default/ { print $3 }')
## find the host's IP
host_ip=$(/sbin/ifconfig eth0 | sed '/inet\ /!d;s/.*r://g;s/\ .*//g')

## give some feedback on what the script found
echo "Running on host: " $host_ip
echo "Using gateway..: " $gw
echo "Run as user....: " $run_user
echo "Using image....: " $pi_img

## set up network bridge on host
pi_if_up()
{
    ip tuntap add dev tap0 mode tap user $run_user
    brctl addbr br0
    brctl setfd br0 0.0
    brctl addif br0 eth0
    brctl addif br0 tap0
    ip link set dev br0 up
    ip link set dev tap0 up
    ip addr del $host_ip/24 dev eth0
    ip addr add $host_ip/24 broadcast + dev br0
    ip route add default via $gw
}

## restore network settings
pi_if_down()
{
    tunctl -d tap0 
    ifconfig br0 down
    brctl delbr br0
    ip addr add $host_ip/24 dev eth0
    ip route add default via $gw
}

if [[ $EUID -ne 0 ]]; then
  echo "This script must be run as root" 1>&2
  exit 1
else

	## set up network
	pi_if_up

	## launch the VM
	qemu-system-arm -kernel kernel-qemu -cpu arm1176 -m 256 -M versatilepb -serial stdio -append "root=/dev/sda2 panic=1" -hda $pi_img -net tap,vlan=0,ifname=tap0,script=no,downscript=no -net nic,vlan=0

	## restore network
	pi_if_down


 fi