Hi Steve,
I remember the original problem with rand(), but not what this change was
about. There used to be a problem with all mod_perl child processes
producing the same series of random numbers, because the seed was
initialized before forking. This sounds like a different problem.
- Perrin
On Mon, Mar 15, 2021 at 9:58 AM Steve Hay
wrote:
> The reason I ask is that it is broken as of perl 5.33.7 and it looks
> like it will remain that way. See:
> https://github.com/Perl/perl5/issues/18617
>
> The problem is that the assignment to PL_hash_seed done in
> modperl_hash_seed_set() is no longer possible, and there is a
> suggestion that it was terribly wrong of mod_perl to be doing this
> anyway so the bug is really in mod_perl, not the perl change that
> causes the build breakage.
>
> If nobody knows any better than I'm inclined to apply the following
> diff to simply switch off MP_NEED_HASH_SEED_FIXUP for perl 5.33.7 and
> higher:
>
> Index: src/modules/perl/modperl_perl.c
> ===
> --- src/modules/perl/modperl_perl.c (revision 1887671)
> +++ src/modules/perl/modperl_perl.c (working copy)
> @@ -210,7 +210,10 @@
> }
> }
>
> -#if !(MP_PERL_VERSION_AT_MOST(5, 8, 0)) && \
> +/* The need for MP_NEED_HASH_SEED_FIXUP is unclear, and it no longer
> works as
> + * of Perl 5.33.7 anyway: See https://github.com/Perl/perl5/issues/18617
> */
> +#if (!(MP_PERL_VERSION_AT_MOST(5, 8, 0)) && \
> + MP_PERL_VERSION_AT_MOST(5, 33, 6)) && \
> (defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT))
> #define MP_NEED_HASH_SEED_FIXUP
> #endif
>
> Using Apache 2.4.46 and mod_perl 2.0.11 on Windows 10 with VS2019 x64
> I get the following test failures from a build with perl 5.33.6:
>
> t\filter\in_bbs_inject_header.t (Wstat: 0 Tests: 36 Failed: 3)
> Failed tests: 22, 26, 30
> t\modperl\env.t (Wstat: 0 Tests: 164 Failed: 17)
> Failed tests: 25, 28, 31, 43, 46, 49, 55, 58, 73, 82
> 85, 88, 91, 97, 142, 145, 163
> t\modperl\setupenv.t (Wstat: 0 Tests: 63 Failed: 6)
> Failed tests: 8, 22, 29, 36, 50, 57
> t\preconnection\note.t(Wstat: 0 Tests: 1 Failed: 1)
> Failed test: 1
>
> As of 5.33.7, the build now fails:
>
> modperl_perl.c(271): error C2102: '&' requires l-value
>
> But with the above patch applied the build works again, and I actually
> have fewer test failures!:
>
> t\modperl\env.t (Wstat: 0 Tests: 158 Failed: 17)
> Failed tests: 25, 28, 31, 43, 46, 49, 55, 58, 67, 76
> 79, 82, 85, 91, 136, 139, 157
> t\preconnection\note.t(Wstat: 0 Tests: 1 Failed: 1)
> Failed test: 1
>
> Please can people test this patch on other setups and report whether
> it causes any breakage.
>
> And if anyone can remember what this hash seed fix-up was intended to
> do then it would be interesting to hear. I worry that something that I
> haven't tested may be requiring it.
>
> The Changes file has this to say about it:
>
> "perl 5.8.1 randomizes the hash seed, because we precalculate the hash
> values of mgv elements the hash seed has to be the same across all
> perl interpreters. So mod_perl now intercepts cases where perl would
> have randomize it, do the seed randomization by itself and tell perl
> to use that value."
>
> That change is rev. 70047 in SVN (30 July 2003), but the commit
> comment is just the same as the Changes comment above. No tests seem
> to have been added, and I don't have an example of anything that
> requires this fix-up in order to work.
>
> Steve
>
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