Warum erhalte ich „neu definieren“ Warnungen mit „verwenden Konstante“ unter mod_perl?

Question

Ich betreiben CGI-Skript mit apache2 und ich habe diese Warnung Linien in error.log ( ich alle ähnlichen Zeilen aus der Ausgabe entfernt ):

[Thu Jul 30 09:39:37 2009] upload.pl: Constant subroutine ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::UPLOAD_DIR redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133.
Constant subroutine
    ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::BUFFER_SIZE redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133 (#1)
[Thu Jul 30 09:39:37 2009] upload.pl: Constant subroutine ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::BUFFER_SIZE redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133.
Constant subroutine
    ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::MAX_FILE_SIZE redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133 (#1)
[Thu Jul 30 09:39:37 2009] upload.pl: Constant subroutine ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::MAX_FILE_SIZE redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133.
Constant subroutine
    ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::MAX_DIR_SIZE redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133 (#1)
[Thu Jul 30 09:39:37 2009] upload.pl: Constant subroutine ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::MAX_DIR_SIZE redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133.
Constant subroutine
    ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::MAX_OPEN_TRIES redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133 (#1)
[Thu Jul 30 09:39:37 2009] upload.pl: Constant subroutine ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::MAX_OPEN_TRIES redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133.
Subroutine dir_size redefined at /home/stanislav/cgi/perl/upload.pl line 79,
     line 133 (#2)
[Thu Jul 30 09:39:37 2009] upload.pl: Subroutine dir_size redefined at /home/stanislav/cgi/perl/upload.pl line 79,  line 133.
Subroutine error redefined at /home/stanislav/cgi/perl/upload.pl line 90,
     line 133 (#2)
[Thu Jul 30 09:39:37 2009] upload.pl: Subroutine error redefined at /home/stanislav/cgi/perl/upload.pl line 90,  line 133.
Argument "" isn't numeric in numeric ge (>=) at
    /home/stanislav/cgi/perl/upload.pl line 62 (#4)
[Thu Jul 30 09:39:37 2009] -e: Argument "" isn't numeric in numeric ge (>=) at /home/stanislav/cgi/perl/upload.pl line 62.
Filehandle OUTPUT opened only for input at /home/stanislav/cgi/perl/upload.pl
    line 69 (#5)
[Thu Jul 30 09:39:37 2009] -e: Filehandle OUTPUT opened only for input at /home/stanislav/cgi/perl/upload.pl line 69.
Constant subroutine
    ModPerl::ROOT::ModPerl::Registry::home_stanislav_cgi_perl_upload_2epl::UPLOAD_DIR redefined at /usr/share/perl/5.10/constant.pm line 115,  line 133 (#1)

Warum sind diese Linien dort und gibt es einen Weg, um sie zu stoppen?

Code, der diese Warnungen aus dem Buch „CGI-Programmierung mit Perl“ (genommen macht, mit einigen Fehler behoben):

#!/usr/bin/perl
use strict;
use warnings;


use CGI;
use CGI::Carp;
#use diagnostics qw/-verbose/;

use Fcntl qw( :DEFAULT :flock );
use constant UPLOAD_DIR     => "/tmp/test_upload/";
use constant BUFFER_SIZE    => 16_384;
use constant MAX_FILE_SIZE  => 1_048_576;       # Limit each upload to 1 MB
use constant MAX_DIR_SIZE   => 100 * 1_048_576; # Limit total uploads to 100 MB
use constant MAX_OPEN_TRIES => 100;

$CGI::DISABLE_UPLOADS   = 0;
$CGI::POST_MAX          = MAX_FILE_SIZE;
my $q = new CGI;
$q->cgi_error and error( $q, "Error transferring file: " . $q->cgi_error );
my $file      = $q->param( "file" )     || error( $q, "No file received." );
my $filename  = $q->param( "filename" ) || error( $q, "No filename entered." );
my $fh        = $q->upload( "file" )     || error( $q, "Something is wrong with file handle." );
#my $fh        = $q->upload( $file );
my $buffer    = "";
if ( dir_size( UPLOAD_DIR ) + $ENV{CONTENT_LENGTH} > MAX_DIR_SIZE ) {
    error( $q, "Upload directory is full." );
}
# Allow letters, digits, periods, underscores, dashes
# Convert anything else to an underscore
$filename =~ s/[^\w.-]/_/g;
if ( $filename =~ /^(\w[\w.-]*)/ ) {
    $filename = $1;
}
else {
    error( $q, "Invalid file name; files must start with a letter or number." );
}
# Open output file, making sure the name is unique
until ( sysopen OUTPUT, UPLOAD_DIR . $filename, O_CREAT | O_EXCL ) {
    $filename =~ s/(\d*)(\.\w+)$/($1||0) + 1 . $2/e;
    $1 >= MAX_OPEN_TRIES and error( $q, "Unable to save your file." );
}
# This is necessary for non-Unix systems; does nothing on Unix
binmode $fh;
binmode OUTPUT;
# Write contents to output file
while ( read( $fh, $buffer, BUFFER_SIZE ) ) {
    print OUTPUT $buffer;
}
close OUTPUT;

if ( -T $fh ) {
    print $q->header("text/plain");
    seek $fh, 0, 0;
    map { print } ;
}

sub dir_size {
    my $dir = shift;
    my $dir_size = 0;

    # Loop through files and sum the sizes; doesn't descend down subdirs
    opendir DIR, $dir or die "Unable to open $dir: $!";
    while ( $_ = readdir DIR ) {
        $dir_size += -s "$dir/$_";
    }
    return $dir_size;
}
sub error {
    my( $q, $reason ) = @_;

    print $q->header( "text/html" ),
          $q->start_html( "Error" ),
          $q->h1( "Error" ),
          $q->p( "Your upload was not procesed because the following error ",
                 "occured: " ),
          $q->p( $q->i( $reason ) ),
          $q->end_html;
    exit;
}

Dieser Code hat ähnliche Leistung: $ perl -e 'sub FOO () { 1 } BEGIN{ *FOO = sub () { 2 }; } print FOO;'

Constant subroutine main::FOO redefined at -e line 1.

I did put no warnings qw/redefine/ aber es half nicht.

Answer 1

AFAIK, können Sie nur diese Warnungen erhalten, wenn Sie Ihren Skript ändern, und dann wird das Skript neu kompilieren von mod_perl für Unterprogramme, die für inlining geeignet sind. Wenn das Unterprogramm neu kompiliert wird, wenn der Wert des es veränderten zurückkehrt, würde dieser neue Wert nicht in den Orten reflektiert werden, wo es vorher inlined wurde.

Wenn Sie den Wert von, sagen wir, BUFFER_SIZE ändern, sollten Sie neu starten apache.

Ich denke auch, mod_perl / Apache :: Registry versehentliche Schließungen zu Ihrem Skript relevant ist.

Answer 2

Bei einer Vermutung, die erste Definition von FOO wird optimiert entfernt. Definieren Sie es mit einer Erklärung im Körper und ich denke, Sie werden feststellen, der Fehler verschwindet.

$ perl -e 'sub FOO () { print 1; } BEGIN{ *FOO = sub () { 2 }; } print FOO;'