Re: [PATCH] test: Remove race between commands run in the same context

[Stefano Brivio <sbrivio@redhat.com>]

On Wed,  5 Apr 2023 11:56:42 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> context_run() has a race condition if two commands are run in close
> proximity (generally involving at least one in the background).  Because we
> always use the same name for the temporary fifo files, if another command
> is issued while the fifos for the first still exist, mkfifo will fail,
> typically causing the entire test script to jam.
> 
> Create unique names for the temporary fifos to avoid this problem.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  test/lib/context | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/test/lib/context b/test/lib/context
> index d9d8260..09cad89 100644
> --- a/test/lib/context
> +++ b/test/lib/context
> @@ -93,8 +93,8 @@ context_run() {
>  	__name="$1"
>  	__log="${LOGDIR}/context_${__name}.log"
>  	__enter="${STATESETUP}/context_${__name}.enter"
> -	__stdout="${STATESETUP}/context_${__name}.stdout"
> -	__stderr="${STATESETUP}/context_${__name}.stderr"
> +	__stdout="$(mktemp -u "${STATESETUP}/context_${__name}.stdout.XXXXXXXX")"
> +	__stderr="$(mktemp -u "${STATESETUP}/context_${__name}.stderr.XXXXXXXX")"

In practice, this is never going to be an issue, but strictly
speaking, -u doesn't guarantee the name is unique.

On the other hand we don't need a loop (or further directories) with
this, so the simplicity of it might be preferable over correctness...

-- 
Stefano