Re: [PATCH v2] libqtest: refuse QTEST_QEMU_BINARY=qemu-kvm

[Thomas Huth]

On 12/04/2021 11.18, Stefan Hajnoczi wrote:
> Some downstreams rename the QEMU binary to "qemu-kvm". This breaks
> qtest_get_arch(), which attempts to parse the target architecture from
> the QTEST_QEMU_BINARY environment variable.
>
> Print an error instead of returning the architecture "kvm". Things fail
> in weird ways when the architecture string is bogus.
>
> Arguably qtests should always be run in a build directory instead of
> against an installed QEMU. In any case, printing a clear error when this
> happens is helpful.
>
> Reported-by: Qin Wang <qinwang@rehdat.com>
> Cc: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>   tests/qtest/libqtest.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
>
> diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
> index 71e359efcd..7caf20f56b 100644
> --- a/tests/qtest/libqtest.c
> +++ b/tests/qtest/libqtest.c
> @@ -910,6 +910,16 @@ const char *qtest_get_arch(void)
>           abort();
>       }
>   
> +    if (!strstr(qemu, "-system-")) {
> +        fprintf(stderr, "QTEST_QEMU_BINARY must end with *-system-<arch> where 
> "
> +                        "'arch' is the target architecture (x86_64, aarch64, "
> +                        "etc). If you are using qemu-kvm or another custom "
> +                        "name, please create a symlink like ln -s "
> +                        "path/to/qemu-kvm qemu-system-x86_64 and use that "
> +                        "instead.\n");

The text is very long ... maybe add some \n to wrap it after 80 columns?
(also not sure whether we really need the second part about the symlink... 
but I also don't mind leaving it in)

> +        abort();

Since this can be triggered by the user, I'd rather use exit(1) instead, 
what do you think?

 Thomas


> +    }
> +
>       return end + 1;
>   }
>