Re: [RFC PATCH-for-6.2 v3] qdev-monitor: Only allow full --global <driver>.<property>=<val> option

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 11/19/21 19:46, BALATON Zoltan wrote:
> On Fri, 19 Nov 2021, Philippe Mathieu-Daudé wrote:
>> When not all fields of the --global option are provided,
>> QEMU might crash:
>>
>>  $ qemu-system-x86_64 -global driver=isa-fdc
>>  qemu-system-x86_64: ../../devel/qemu/qapi/string-input-visitor.c:394:
>>  string_input_visitor_new: Assertion `str' failed.
>>  Aborted (core dumped)
>>
>> Fix by only allowing --global with all 3 fields:
>>
>>  $ qemu-system-x86_64 -global driver=isa-fdc
>>  Invalid 'global' option format. It must be provided as:
>>    --global <driver>.<property>=<value>
>>
>> Reported-by: Thomas Huth <thuth@redhat.com>
>> Suggested-by: Markus Armbruster <armbru@redhat.com>
>> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/604
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>> v3: Change qemu_global_option (Markus)
>>
>> Supersedes: <20211119122911.365036-1-philmd@redhat.com>
>> ---
>> softmmu/qdev-monitor.c | 9 +++------
>> 1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
>> index 01f3834db57..558272b147c 100644
>> --- a/softmmu/qdev-monitor.c
>> +++ b/softmmu/qdev-monitor.c
>> @@ -1029,13 +1029,10 @@ int qemu_global_option(const char *str)
>>         qemu_opt_set(opts, "value", str + offset + 1, &error_abort);
>>         return 0;
>>     }
>> +    printf("Invalid 'global' option format. It must be provided as:\n");
>> +    printf("  --global <driver>.<property>=<value>\n");
> 
> Should these be something else tnan plain printf? (Such as qemu_prinf or
> qdev_printf or similar? Not sure how these work but plain printf in QEMU
> is usually not what's meant.)

I thought so first, but qemu_opts_print_help() calls plain printf()...

> Regards,
> BALATON Zoltan
> 
>> -    opts = qemu_opts_parse_noisily(&qemu_global_opts, str, false);
>> -    if (!opts) {
>> -        return -1;
>> -    }