fred at redhotpenguin
Sep 25, 2007, 10:52 AM
Post #2 of 16
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Re: [mp2] mod_perl closes apache's stdin and/or stdout
[In reply to]
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Dmitry Karasik wrote:
> Hello,
>
> In mixed environment of mod_perl and cgi, cgi scripts may choose to not use
> mod_perl request interface, and read content of POST requests directly from
> STDIN. mod_perl during the initialization process closes file descriptor 0,
> and frees it for further reuse in other processes. Therefore, any cgi script
> executing after mod_perl is initialized, and in the same process tree, will
> have file descriptor 0 closed. The concrete example where this behavior leads
> to impossibility of processing POST requests is reported earlier and is located
> at
>
> http://marc.info/?l=apache-modperl&m=119062450730646&w=2
>
> The proposed patch fixes the issue, however, not being a perl guts expert, I
> would urge someone with a deeper knowledge of perl to look at it first. Chances
> are that there exists a mechanism in perl that allows non-destructive
> duplication and overloading of perl IO handles.
I am not a perl guts expert either (gozer??), but looking through the
perl source it looks like this idiom is used in a few places. But we
really need a reproducible test case to verify that this is indeed a
problem.
I took a quick swing at putting one together but my mod_perl environment
is a bit screwed up right now. Can you see if it runs on your setup?
And hopefully passes with your change, and fails without? This test may
not work at all :) but if it does and this problem is reproducible then
that improves our chances of getting the fix accepted in some form.
Index: ModPerl-Registry/t/conf/extra.conf.in
===================================================================
--- ModPerl-Registry/t/conf/extra.conf.in (revision 543707)
+++ ModPerl-Registry/t/conf/extra.conf.in (working copy)
@@ -182,6 +182,17 @@
PerlResponseHandler ModPerl::Registry
</Location>
+### test for mixed mod_perl/cgi environment ###
+<Location /stdin_override/mod_perl>
+ SetHandler perl-script
+ PerlResponseHandler ModPerl::Registry
+ PerlOptions +ParseHeaders
+</Location>
+
+<Location /stdin_override/cgi>
+ SetHandler cgi-script
+</Location>
+
### deflate tests ###
<IfModule mod_alias.c>
Alias /registry_bb_deflate/ @ServerRoot@/cgi-bin/
Index: ModPerl-Registry/t/cgi-bin/stdin.pl
===================================================================
--- ModPerl-Registry/t/cgi-bin/stdin.pl (revision 0)
+++ ModPerl-Registry/t/cgi-bin/stdin.pl (revision 0)
@@ -0,0 +1,29 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+use CGI qw/:standard/;
+
+print <<END;
+Content-type: text/html
+
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html>
+ <body>
+ <form method="post"><input type="submit" name="submit" value="Submit">
+ </form>
+END
+
+if (param()) {
+ my $submit = param('submit');
+ if ($submit) {
+ print "<p>submitted</p>";
+ }
+}
+
+print <<END;
+ </body>
+</html>
+END
+
Index: ModPerl-Registry/t/stdin.t
===================================================================
--- ModPerl-Registry/t/stdin.t (revision 0)
+++ ModPerl-Registry/t/stdin.t (revision 0)
@@ -0,0 +1,24 @@
+use strict;
+use warnings FATAL => 'all';
+
+use Apache::Test;
+use Apache::TestUtil;
+use Apache::TestRequest qw(POST);
+
+plan tests => 2, need [qw(CGI)],
+ need_min_module_version CGI => 3.08;
+
+{
+ my $url = "/stdin_override/mod_perl";
+ my $res = POST $url;
+
+ ok t_cmp($res->content,
+ qr{submitted},
+ "form submission ok under mod_perl");
+
+ $url = "/stdin_override/cgi";
+ $res = POST $url;
+ ok t_cmp($res->content,
+ qr{submitted},
+ "stdin reset, form submission ok under cgi");
+}
>
> Cheers,
> Dmitry Karasik
>
> --- modperl_io.c.orig 2007-09-25 15:36:02.000000000 +0200
> +++ modperl_io.c 2007-09-25 15:35:51.000000000 +0200
> @@ -129,6 +129,15 @@
> Perl_croak(aTHX_ "Failed to dup STDIN: %" SVf, get_sv("!", TRUE));
> }
>
> + /* In mixed environment of mod_perl and cgi scripts, cgi scripts may read content of
> + * POST requests off STDIN. do_close() calls actual close(0), freeing the descriptor 0
> + * for reuse, and creating havoc for anyone reading from file descriptor 0.
> + * This hack changes the IO type to IoTYPE_STD, because do_close() does not call
> + * underlying close() on IO handles of these types, but does free the associated
> + * resources. */
> + if ( IoIFP(io) && PerlIO_fileno(IoIFP(io)) == 0)
> + IoTYPE(io) = IoTYPE_STD;
> +
> /* similar to PerlIO::scalar, the PerlIO::Apache layer doesn't
> * have file descriptors, so STDIN must be closed before it can
> * be reopened */
>
> 2. Used Components and their Configuration:
>
> *** mod_perl version 2.000003
>
> *** using /usr/ports/www/mod_perl2/work/mod_perl-2.0.3/lib/Apache2/BuildConfig.pm
>
> *** Makefile.PL options:
> MP_APR_LIB => aprext
> MP_APXS => /usr/local/sbin/apxs
> MP_COMPAT_1X => 1
> MP_GENERATE_XS => 1
> MP_LIBNAME => mod_perl
> MP_USE_DSO => 1
>
>
> *** The httpd binary was not found
>
>
> *** (apr|apu)-config linking info
>
> -L/usr/local/lib -laprutil-1 -lexpat -liconv -L/usr/local/lib
> -L/usr/local/lib -lapr-1 -lcrypt -lpthread
>
>
> *** /usr/local/bin/perl -V
> Summary of my perl5 (revision 5 version 8 subversion 8) configuration:
> Platform:
> osname=freebsd, osvers=6.2-release, archname=i386-freebsd-64int
> uname='freebsd freebsd.org 6.2-release freebsd 6.2-release #0: sat oct 14 21:57:31 pdt 2006 kris [at] freebsd:usrsrcsysmagickernelpath i386 '
> config_args='-sde -Dprefix=/usr/local -Darchlib=/usr/local/lib/perl5/5.8.8/mach -Dprivlib=/usr/local/lib/perl5/5.8.8 -Dman3dir=/usr/local/lib/perl5/5.8.8/perl/man/man3 -Dman1dir=/usr/local/man/man1 -Dsitearch=/usr/local/lib/perl5/site_perl/5.8.8/mach -Dsitelib=/usr/local/lib/perl5/site_perl/5.8.8 -Dscriptdir=/usr/local/bin -Dsiteman3dir=/usr/local/lib/perl5/5.8.8/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Ui_malloc -Ui_iconv -Uinstallusrbinperl -Dcc=cc -Duseshrplib -Dccflags=-DAPPLLIB_EXP="/usr/local/lib/perl5/5.8.8/BSDPAN" -Doptimize=-O2 -fno-strict-aliasing -pipe -Ud_dosuid -Ui_gdbm -Dusethreads=n -Dusemymalloc=y -Duse64bitint'
> hint=recommended, useposix=true, d_sigaction=define
> usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
> useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
> use64bitint=define use64bitall=undef uselongdouble=undef
> usemymalloc=y, bincompat5005=undef
> Compiler:
> cc='cc', ccflags ='-DAPPLLIB_EXP="/usr/local/lib/perl5/5.8.8/BSDPAN" -DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include',
> optimize='-O2 -fno-strict-aliasing -pipe ',
> cppflags='-DAPPLLIB_EXP="/usr/local/lib/perl5/5.8.8/BSDPAN" -DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include'
> ccversion='', gccversion='3.4.6 [FreeBSD] 20060305', gccosandvers=''
> intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=12345678
> d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
> ivtype='long long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
> alignbytes=4, prototype=define
> Linker and Libraries:
> ld='cc', ldflags =' -Wl,-E -L/usr/local/lib'
> libpth=/usr/lib /usr/local/lib
> libs=-lm -lcrypt -lutil
> perllibs=-lm -lcrypt -lutil
> libc=, so=so, useshrplib=true, libperl=libperl.so
> gnulibc_version=''
> Dynamic Linking:
> dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' -Wl,-R/usr/local/lib/perl5/5.8.8/mach/CORE'
> cccdlflags='-DPIC -fPIC', lddlflags='-shared -L/usr/local/lib'
>
>
> Characteristics of this binary (from libperl):
> Compile-time options: MYMALLOC PERL_MALLOC_WRAP USE_64_BIT_INT
> USE_LARGE_FILES USE_PERLIO
> Locally applied patches:
> defined-or
> Built under freebsd
> Compiled at Oct 15 2006 05:04:59
> %ENV:
> PERL_LWP_USE_HTTP_10="1"
> @INC:
> /usr/local/lib/perl5/5.8.8/BSDPAN
> /usr/local/lib/perl5/site_perl/5.8.8/mach
> /usr/local/lib/perl5/site_perl/5.8.8
> /usr/local/lib/perl5/site_perl
> /usr/local/lib/perl5/5.8.8/mach
> /usr/local/lib/perl5/5.8.8
> .
>
> *** Packages of interest status:
>
> Apache2 : -
> Apache2::Request : -
> CGI : 3.15
> ExtUtils::MakeMaker: 6.30, undef
> LWP : 5.805
> mod_perl : -
> mod_perl2 : 2.000003
>
>
> This report was generated by t/REPORT on Tue Sep 25 13:39:09 2007 GMT.
>
> -------------8<---------- End Bug Report --------------8<----------
>
> Note: Complete the rest of the details and post this bug report to
> modperl <at> perl.apache.org. To subscribe to the list send an empty
> email to modperl-subscribe [at] perl
>
>
>
>
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