A kiss wrapper script for qemu

qemu.sh

#!/usr/bin/env bash
#
#Copyright 2024 Georgios Politis
#
#Permission is hereby granted, free of charge, to any person obtaining a copy
#of this software and associated documentation files (the “Software”), to deal
#in the Software without restriction, including without limitation the rights
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#copies of the Software, and to permit persons to whom the Software is
#furnished to do so, subject to the following conditions:
#
#The above copyright notice and this permission notice shall be included in all
#copies or substantial portions of the Software.
#
#THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
#SOFTWARE.

QEMU_ENV="$1"
if [ ! -f "$QEMU_ENV" ]; then
  echo "Usage:

    $0 QEMU_ENV

Example QEMU_ENV file
---------------------

QEMU_BIN=/opt/local/bin/qemu-system-x86_64
QEMU_ACCEL=hvf
QEMU_CPU=host,-pdpe1gb
QEMU_SMP=2
QEMU_MEM=4G
QEMU_NIC=user
QEMU_DRIVE=file="$HOME/Virtual Machines/root.qcow2",if=virtio
QEMU_CDROM="$HOME/Donwloads/ubuntu-24.04.1-desktop-amd64.iso"

Notes
-----

Some env variables are optional. You can grep qemu.sh to see all the available
env variables.

Please note that this is just an example env file. You should check the QEMU
man page for the available values for the different env variables and make sure
they match your environment and needs. For example, hvf acceleration is only
available on macOS, you need to adjust this for other host operating systems.

Getting started
---------------

Assuming you have QEMU installed on your system, you need to :

1. Download the ISO image of your favorite ditro.
2. Create a root disk for your VM with:

    qemu-img create -f qcow2 root.qcow2 10G

3. Create an env file to describe your VM using the example above as a template.
4. Run your VM with qemu.sh" 1>&2
  exit 1
fi

set -a
source "$QEMU_ENV"
set +a

if [ -z "$QEMU_BIN" ]
then
  echo "QEMU_BIN environment variable is not set." 1>&2
  exit 1
fi

if [ ! -x "$QEMU_BIN" ]
then
  echo "$QEMU_BIN is not executable." 1>&2
  exit 1
fi

# I am using associative arrays for the optional arguments. This is a bashism
# that I would love to remove so that the script can be run in any shell.

declare -a QEMU_OPTIONAL_ARGS
if [ ! -z "$QEMU_USBDEVICE" ]
then
  QEMU_OPTIONAL_ARGS+=("-usbdevice" "$QEMU_USBDEVICE")
fi

if [ ! -z "$QEMU_CDROM" ]
then
  QEMU_OPTIONAL_ARGS+=("-cdrom" "$QEMU_CDROM")
fi

if [ ! -z "$QEMU_DISPLAY" ]
then
  QEMU_OPTIONAL_ARGS+=("-display" "$QEMU_DISPLAY")
fi

exec "$QEMU_BIN" -accel "$QEMU_ACCEL" -cpu "$QEMU_CPU" \
  -smp "$QEMU_SMP" -m "$QEMU_MEM" -nic "$QEMU_NIC" -drive "$QEMU_DRIVE" \
  "${QEMU_OPTIONAL_ARGS[@]}"