Re: [PATCH] log: Fix result of strstr to 'const char *'

["Cédric Le Goater" <clg@redhat.com>]

On 12/9/25 16:21, Daniel P. Berrangé wrote:
> On Tue, Dec 09, 2025 at 03:07:04PM +0000, Peter Maydell wrote:
>> On Tue, 9 Dec 2025 at 15:04, Cédric Le Goater <clg@redhat.com> wrote:
>>>
>>> Assigning the result of strstr() to a 'char *' is unsafe since
>>> strstr() returns a pointer into the original string which is a
>>> read-only 'const char *' string. Newer compilers
>>
>> Which ones? Or does this depend on how the libc headers have
>> marked up the strstr() prototype?
> 
> I don't believe it is compiler related, rather this is an
> ehancement in glibc 2.42.9000 / git master
> 
>    https://sourceware.org/git/?p=glibc.git;a=commit;h=cd748a63ab1a7ae846175c532a3daab341c62690
> 
> AFAICT it should work with any gcc we have
> 
> Although the commit talks about C23, we get it regardless as we have
> _GNU_SOURCE defined.

yes. glibc 2.42.9000 has :


+# if __GLIBC_USE (ISOC23) && defined __glibc_const_generic && !defined _LIBC
+#  define strstr(HAYSTACK, NEEDLE)			\
+  __glibc_const_generic (HAYSTACK, const char *,	\
+			 strstr (HAYSTACK, NEEDLE))
+# endif


C.