Re: [PATCH v3] Fix const qualifier build errors with recent glibc

["Cédric Le Goater" <clg@redhat.com>]

On 12/10/25 11:35, Michael Tokarev wrote:
> On 12/9/25 20:43, Cédric Le Goater wrote:
>> A recent change in glibc 2.42.9000 [1] changes the return type of
>> strstr() and other string functions to be 'const char *' when the
>> input is a 'const char *'.
>>
>> This breaks the build in various files with errors such as :
>>
>>    error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
>>      208 |         char *pidstr = strstr(filename, "%");
>>          |                        ^~~~~~
>>
>> Fix this by changing the type of the variables that store the result
>> of these functions to 'const char *'.
>>
>> [1] https://sourceware.org/git/?p=glibc.git;a=commit;h=cd748a63ab1a7ae846175c532a3daab341c62690
> 
> I'm picking this up for qemu-stable (10.0 & 10.1 series)
> (together with 83f6dceb8f5c "qga: Fix ubsan warning").
> Please let me know if I shouldn't.

This is a partial fix for the recent glibc update. We need at least
two other patches. One rewriting vubr_parse_host_port() as Peter
proposed and another for :

../hw/i386/x86-common.c:827:11: error: assignment discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
   827 |     vmode = strstr(kernel_cmdline, "vga=");

which is missing in v3.

Anyhow, there is no harm in taking this first part. Future backports
should be simple enough.

Thanks,

C.