[Buildroot] [PATCH v2 5/7] board/qemu/*/launch.sh: add qemu launch script

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

On Sun,  5 May 2019 18:53:57 +0200
Jugurtha BELKALEM <jugurtha.belkalem@smile.fr> wrote:

> diff --git a/board/qemu/aarch64-virt/launch.sh b/board/qemu/aarch64-virt/launch.sh
> new file mode 100755
> index 0000000..c6af589
> --- /dev/null
> +++ b/board/qemu/aarch64-virt/launch.sh
> @@ -0,0 +1,21 @@
> +#!/bin/bash
> +
> +qemu_command='qemu-system-aarch64 -M virt -cpu cortex-a53 -nographic -smp 1 -kernel output/images/Image -append "root=/dev/vda console=ttyAMA0" -netdev user,id=eth0 -device virtio-net-device,netdev=eth0 -drive file=output/images/rootfs.ext4,if=none,format=raw,id=hd0 -device virtio-blk-device,drive=hd0'
> +
> +function DisplayReadme {
> +	echo "Run the emulation with:
> +
> +${qemu_command}
> +
> +The login prompt will appear in the terminal that started Qemu.
> +
> +Tested with QEMU 2.12.0"
> +}
> +
> +if [ ! -z $1 ] && [ $1 = "-h" ]
> +then
> +	DisplayReadme
> +else
> +	
> +	echo "${qemu_command}"
> +fi

I am not thrilled by the complexity of those scripts. Why isn't the
script just a single line that runs Qemu ? Perhaps the only argument
that would be sensible to have is an optional argument to pass the
output directory.

So just:

#!/bin/bash
qemu-system-aarch64 -M virt -cpu cortex-a53 -nographic -smp 1 -kernel ${0:-output}/images/Image -append "root=/dev/vda console=ttyAMA0" -netdev user,id=eth0 -device virtio-net-device,netdev=eth0 -drive file=${0:-output}/images/rootfs.ext4,if=none,format=raw,id=hd0 -device virtio-blk-device,drive=hd0

Would be enough. But on the other hand, in the toolchain-builders
stuff, we simply use the existing readme.txt contents. We do this:

  test_qemu_cmd=$(grep qemu-system ${buildroot_dir}/board/qemu/${test_board_dir}/readme.txt)

And this gives us the Qemu command to run the qemu emulation. Perhaps
we should do this as well here, and avoid the launch.sh scripts
altogether ? In any case, we shouldn't duplicate this information
between the launch.sh script and the readme.txt file. So if you go the
launch.sh way, we need to adjust the readme.txt files accordingly.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com