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

[Thomas Huth <thuth@redhat.com>]

On 12/04/2021 16.35, Thomas Huth wrote:
> On 12/04/2021 16.21, Stefan Hajnoczi wrote:
>> On Mon, Apr 12, 2021 at 11:35:40AM +0200, Thomas Huth wrote:
>>> 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?
>>
>> Sure, but in that case I guess the abort() call above also needs to be
>> changed? It is triggered when the QTEST_QEMU_BINARY path does not
>> contain a hyphen ('-') and it currently aborts.
> 
> Drat, you're right, and it was even me who added that :-/ ... if you've got 
> some spare minutes, could you send a patch for that, too, please? (Otherwise 
> I'll do it later)

Never mind, I just saw that you've fixed it in v3 already :-)

  Thomas