Shared Memory using IPC::Shareable - Can't use an undefined value as an ARRAY reference

[mr_p]

Hello Monks,

I am working on a program that forks 3 childern. The first child acts as a perent to the next two.

Job for the first Child:

- Update a Variable called dirListing.

- Checks filesDownloaded array and takes action based on filename.

Job for two childern:

- Check dirListing array content and take action based on the filename.

- If action is taken then added filename to filesDownloaded array.

when I run the program I keep getting the following error.

Can't use an undefined value as an ARRAY reference at /shmem/lib/lib/perl5/site_perl//5.8.5/IPC/Shareable.pm line 446. IPC::Shareable::FETCHSIZE('IPC::Shareable=HASH(0x79baf0)') called at ./test_nfxftpd line 63

Please help, I have watsed so much time with this, Thanks in advance.

#! /usr/bin/perl -w

use strict;
use lib "/nss/nfx/shmem/lib/lib";
use lib "/nss/nfx/shmem/lib/lib64";
use lib "/nss/nfx/shmem/lib/lib/perl5/site_perl/";

use File::Basename;
use Getopt::Long;
use File::Copy;
use strict;
#use IPC::Shareable;
use IPC::Shareable qw();

my $child;
my $serv_id;
my $maxRcvrCount;
my $stripeInstance;
my $maxStripeInstance;

my $user;
my @ftpDirectoryListing=();
my @dirListing=();
my @filesDownloaded=();
my $glue = 'data';
my %options = (
     create    => 1,
     exclusive => 0,
     mode      => 0644,
     destroy   => 1,
 );

my $dirListingHandle = tie @dirListing, 'IPC::Shareable', 'data', \%op
+tions;
my $filesDownloadedHandle = tie @filesDownloaded, 'IPC::Shareable', 'k
+ala', \%options;

sub pollDaemonParent
{
    my $user = $_[0];
    my @previousListing=(); my @currentListing=();
    while (1)
    {
        @previousListing = @currentListing;
        @currentListing = getListing($user);

        $dirListingHandle->shlock();
        @dirListing = deDupArray1(\@previousListing, \@currentListing)
+;

        print "Parent: currentListing: @currentListing    dirListing: 
+@dirListing\n";

        $dirListingHandle->shunlock();

        deleteRemoteFiles1();
        select (undef, undef, undef,.5);
    }
}
sub deleteRemoteFiles1
{
    # TODO: Get list and delete from server. once deleted
    $filesDownloadedHandle->shlock();
    if ($#filesDownloaded >=  0)
    {
        print "\nParent: deleteListing: @filesDownloaded\n";
    }
    foreach (@filesDownloaded)
    { deleteFile($_); }
    @filesDownloaded=();
    $filesDownloadedHandle->shunlock();
}
sub pollDaemonChild
{
    my $user = $_[0];

    print "ChildStarted: $stripeInstance\n";
    while (1)
    {

        @ftpDirectoryListing = ();

        $dirListingHandle->shlock();
        @ftpDirectoryListing = @dirListing;
        $dirListingHandle->shunlock();

        if ($#ftpDirectoryListing >=  0)
        {
            print "Child - @ftpDirectoryListing: @ftpDirectoryListing\
+n";
        }
        select (undef, undef, undef,1);

    }
}
sub getListing
{
    my @ftpListing1 = ();
    push (@ftpListing1, "abc.xml");
    push (@ftpListing1, "xyz.xml");

    return @ftpListing1;
}
sub deDupArray1
{
    my @difference = ("dedup1.xml", "dedup2.xml");
    return @difference;
}
sub addToDeleteList
{
    $|++;
    $filesDownloadedHandle->shlock();
    push (@filesDownloaded, "$_[0]");
    $filesDownloadedHandle->shunlock();
}
# main
{
    $user = "IAmUser";
    $serv_id = "1";
    $maxRcvrCount = "5";
    $stripeInstance = "1" ;
    $maxStripeInstance = "3";

    $SIG{'ALRM'} = 'sig_alrm';

my $startingInstanceNum=1;
my @kids;
for (1 .. $maxStripeInstance)
{

    $stripeInstance = $startingInstanceNum;
    print "stripeInstance: $startingInstanceNum\n";

    unless ($child = fork)
    {        # i'm the child
        die "cannot fork: $!" unless defined $child;
        if($stripeInstance == 1 )
        {
            pollDaemonParent($user);
        }
        else
        {
            pollDaemonChild($user);
        }
        exit;
    }

    push @kids, $child;  # in case we care about their pids
    $startingInstanceNum++;
}

while (1)
{
    sleep 1;
}

}

[zentara]

You might want to try this script, which was worked out by andThenThereWasPERL in forking with Storable and IPC::ShareLite. It may give you a way to get it working with Parallel::ForkManager, or at least clue you in as to why your code is failing.

#!/usr/bin/perl
use strict;
use Parallel::ForkManager;
use IPC::Shareable;

my $glue = $$;
my %options = (
     create    => 1,
     exclusive => 0,
     mode      => 0644,
     destroy   => 1,
);
my %final_parent_hash;

my $parent_share = tie %final_parent_hash, 'IPC::Shareable', $glue, { 
+%options } or die "parent : tie failed\n";

my $fork_manager =  new Parallel::ForkManager(5);

foreach my $child ( 1 .. 10 ) {
    my $pid = $fork_manager->start($child) and next;
    my %options = (
     create    => 0,
     exclusive => 0,
     mode      => 0644,
     destroy   => 0,
    );
    my %child_hash;
    my $child_share = tie %child_hash, 'IPC::Shareable', $glue, { %opt
+ions } or die "client: tie failed\n";
    for my $id (1 .. 20) {
        my $key = $child . '-' . $id;
        $child_share->shlock;
        $final_parent_hash{$key} = qq{|Kid $child pushed $id};
        $child_share->shunlock;
    }
    $fork_manager->finish($child);
}
print "Waiting for Children...\n";
$fork_manager->wait_all_children;
my $sleep_ctr = 10;
while ($sleep_ctr) {
    if ((keys %final_parent_hash) == 200) {
        last;
    }
    sleep 1;
    $sleep_ctr--;
}
foreach my $child ( 1 .. 10 ) {
    for my $id (1 .. 20) {
        my $key = $child . '-' . $id;
        if (! exists $final_parent_hash{$key} ) {
            print "Missing data for Kid $child , data $id\n";
        }
        else {
            print "$key = $final_parent_hash{$key}\n";
        }
    }
}
IPC::Shareable->clean_up_all;

[rowdog]

You tie @dirListing and then go on to fork. I'm not sure that tied variables survive a fork and, in any case, they're not safe to access from more than one child. fork before tie.