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Posted to modperl@perl.apache.org by "Philippe M. Chiasson" <go...@ectoplasm.org> on 2005/09/22 01:35:33 UTC
[patch mp2] Fixes to $0 handling [Was: Directive changes the
command name]
I've finally had time to dig deeper in the troubling $0 and process display
problems that seem to exist at least on *BSDs and HP-UX.
On linux, modifications to the original argv[0] will directy modify the process
information. On some other OSes, some special API is needed.
Perl's $0 magic handling correctly handles these OS differences and just does
the right thing.
So, simply passing Perl a _copy_ of argv[0] does disable $0 magic on Linux, but
not on the other OSes where it just calls the correct API (setproctitle() on BSDs)
On top of that, calling perl_parse() as is commonly done for embedders with
an argument of -e0, results in an initial $0 of '-e'. And that's what
is hapenning to pradeep.
But that's not all ;-) ap_server_argv0 _is_ _not_ httpd' argv[0], it's argv[0]
skipped forward to remove path components and leave only the binary's name
(httpd). The correct way to get at the real argv[0] is in server->proc->argv
All this combined has led to a more than troubling bug.
The correct solution (see patch) is:
- Reset $0 to the _real_ argv[0] after calling perl_parse()
/* Also need to fix PL_origalen */
PL_origalen = strlen(argv[0])+1;
/* argv[0] = '/usr/bin/httpd' */
sv_setpv_mg(get_sv("0",0), argv[0]);
- Use the real argv[0] (s->process->argv) and not a copy
--
Philippe M. Chiasson m/gozer\@(apache|cpan|ectoplasm)\.org/ GPG KeyID : 88C3A5A5
http://gozer.ectoplasm.org/ F9BF E0C2 480E 7680 1AE5 3631 CB32 A107 88C3A5A5
Re: [patch mp2] Fixes to $0 handling [Was: Directive changes
the command name]
Posted by "Philippe M. Chiasson" <go...@ectoplasm.org>.
Philip M. Gollucci wrote:
> Philippe M. Chiasson wrote:
>
>> I've finally had time to dig deeper in the troubling $0 and process
>> display
>> problems that seem to exist at least on *BSDs and HP-UX.
>>
>> [...]
>>
>> The correct solution (see patch) is:
>>
>> - Reset $0 to the _real_ argv[0] after calling perl_parse()
>> /* Also need to fix PL_origalen */
>> PL_origalen = strlen(argv[0])+1;
>> /* argv[0] = '/usr/bin/httpd' */
>> sv_setpv_mg(get_sv("0",0), argv[0]);
>>
>> - Use the real argv[0] (s->process->argv) and not a copy
>
> Dear God!
>
> +1
>
> The test suite passes 100% with this applied and manual inspection of ps
> looks good.
Great, checked in as change r291193
> That on FreeBSD... hopefully I'll have some Open/Net BSD in the near
> future too.
--
Philippe M. Chiasson m/gozer\@(apache|cpan|ectoplasm)\.org/ GPG KeyID : 88C3A5A5
http://gozer.ectoplasm.org/ F9BF E0C2 480E 7680 1AE5 3631 CB32 A107 88C3A5A5
Re: [patch mp2] Fixes to $0 handling [Was: Directive changes
the command name]
Posted by "Philippe M. Chiasson" <go...@ectoplasm.org>.
Philip M. Gollucci wrote:
> Philippe M. Chiasson wrote:
>
>> I've finally had time to dig deeper in the troubling $0 and process
>> display
>> problems that seem to exist at least on *BSDs and HP-UX.
>>
>> [...]
>>
>> The correct solution (see patch) is:
>>
>> - Reset $0 to the _real_ argv[0] after calling perl_parse()
>> /* Also need to fix PL_origalen */
>> PL_origalen = strlen(argv[0])+1;
>> /* argv[0] = '/usr/bin/httpd' */
>> sv_setpv_mg(get_sv("0",0), argv[0]);
>>
>> - Use the real argv[0] (s->process->argv) and not a copy
>
> Dear God!
>
> +1
>
> The test suite passes 100% with this applied and manual inspection of ps
> looks good.
Great, checked in as change r291193
> That on FreeBSD... hopefully I'll have some Open/Net BSD in the near
> future too.
--
Philippe M. Chiasson m/gozer\@(apache|cpan|ectoplasm)\.org/ GPG KeyID : 88C3A5A5
http://gozer.ectoplasm.org/ F9BF E0C2 480E 7680 1AE5 3631 CB32 A107 88C3A5A5
Re: [patch mp2] Fixes to $0 handling [Was: Directive changes
the command name]
Posted by "Philip M. Gollucci" <pg...@p6m7g8.com>.
Philippe M. Chiasson wrote:
> I've finally had time to dig deeper in the troubling $0 and process display
> problems that seem to exist at least on *BSDs and HP-UX.
>
> On linux, modifications to the original argv[0] will directy modify the process
> information. On some other OSes, some special API is needed.
>
> Perl's $0 magic handling correctly handles these OS differences and just does
> the right thing.
>
> So, simply passing Perl a _copy_ of argv[0] does disable $0 magic on Linux, but
> not on the other OSes where it just calls the correct API (setproctitle() on BSDs)
>
> On top of that, calling perl_parse() as is commonly done for embedders with
> an argument of -e0, results in an initial $0 of '-e'. And that's what
> is hapenning to pradeep.
>
> But that's not all ;-) ap_server_argv0 _is_ _not_ httpd' argv[0], it's argv[0]
> skipped forward to remove path components and leave only the binary's name
> (httpd). The correct way to get at the real argv[0] is in server->proc->argv
>
> All this combined has led to a more than troubling bug.
>
> The correct solution (see patch) is:
>
> - Reset $0 to the _real_ argv[0] after calling perl_parse()
> /* Also need to fix PL_origalen */
> PL_origalen = strlen(argv[0])+1;
> /* argv[0] = '/usr/bin/httpd' */
> sv_setpv_mg(get_sv("0",0), argv[0]);
>
> - Use the real argv[0] (s->process->argv) and not a copy
Dear God!
+1
The test suite passes 100% with this applied and manual inspection of ps looks
good.
That on FreeBSD... hopefully I'll have some Open/Net BSD in the near future too.
--
END
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Nothing is impossible.
Philip M. Gollucci (pgollucci@p6m7g8.com) 301.254.5198
Consultant / http://p6m7g8.net/Resume/
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