Nginx - Perl wrapper

Install perl-FCGI:

yum install perl-FCGI

Create /usr/bin/fastcgi-wrapper.pl:

vim /usr/bin/perlwrapper.pl

#!/usr/bin/perl

use FCGI;
use Socket;
use POSIX qw(setsid);

require 'syscall.ph';

&daemonize;

#this keeps the program alive or something after exec'ing perl scripts
END() { } BEGIN() { }
*CORE::GLOBAL::exit = sub { die "fakeexit\nrc=".shift()."\n"; };
eval q{exit};

if ($@) {

    exit unless $@ =~ /^fakeexit/;
};

&main;

sub daemonize() {

    chdir '/'                 or die "Can't chdir to /: $!";
    defined(my $pid = fork)   or die "Can't fork: $!";
    exit if $pid;
    setsid                    or die "Can't start a new session: $!";
    umask 0;
}

sub main {
    #$socket = FCGI::OpenSocket( "127.0.0.1:8999", 10 ); #use IP sockets
    $socket = FCGI::OpenSocket( "/var/run/fastcgi.sock", 10 );
    $request = FCGI::Request( \*STDIN, \*STDOUT, \*STDERR, \%req_params, $socket );

    if ($request) { request_loop()};
        FCGI::CloseSocket( $socket );
}

sub request_loop {

    while( $request->Accept() >= 0 ) {

       #processing any STDIN input from WebServer (for CGI-POST actions)
       $stdin_passthrough ='';
       $req_len = 0 + $req_params{'CONTENT_LENGTH'};

       if (($req_params{'REQUEST_METHOD'} eq 'POST') && ($req_len != 0) ){

            my $bytes_read = 0;

            while ($bytes_read < $req_len) {

                my $data = '';
                my $bytes = read(STDIN, $data, ($req_len - $bytes_read));
                last if ($bytes == 0 || !defined($bytes));
                $stdin_passthrough .= $data;
                $bytes_read += $bytes;
            }
        }

        #running the cgi app
        if ( (-x $req_params{SCRIPT_FILENAME}) &&  #can I execute this?
             (-s $req_params{SCRIPT_FILENAME}) &&  #Is this file empty?
             (-r $req_params{SCRIPT_FILENAME})     #can I read this file?
        ){

            pipe(CHILD_RD, PARENT_WR);
            my $pid = open(KID_TO_READ, "-|");

            unless(defined($pid)) {
                print("Content-type: text/plain\r\n\r\n");
                print "Error: CGI app returned no output - ";
                print "Executing $req_params{SCRIPT_FILENAME} failed !\n";
                next;
            }

        if ($pid > 0) {

            close(CHILD_RD);
            print PARENT_WR $stdin_passthrough;
            close(PARENT_WR);
            while(my $s = <KID_TO_READ>) { print $s; }
            close KID_TO_READ;
            waitpid($pid, 0);

        } else {

            foreach $key ( keys %req_params){

                    $ENV{$key} = $req_params{$key};
                }

                # cd to the script's local directory
                if ($req_params{SCRIPT_FILENAME} =~ /^(.*)\/[^\/]+$/) {

                    chdir $1;
                }

                close(PARENT_WR);
                close(STDIN);
                #fcntl(CHILD_RD, F_DUPFD, 0);
                syscall(&SYS_dup2, fileno(CHILD_RD), 0);
                #open(STDIN, "<&CHILD_RD");
                exec($req_params{SCRIPT_FILENAME});
                die("exec failed");
            }

        } else {
            print("Content-type: text/plain\r\n\r\n");
            print "Error: No such CGI app - $req_params{SCRIPT_FILENAME} may not ";
            print "exist or is not executable by this process.\n";
        }
    }
}

Make the wrapper executable:

chmod +x /usr/bin/fastcgi-wrapper.pl

Create service file:

vim /usr/lib/systemd/system/perlwrapper.service

[Unit]
Description = Perl FastCGI Wrapper Service
Requires=network-online.target
After=network-online.target

[Service]
Type=forking
ExecStart=/usr/bin/perlwrapper.pl

[Install]
WantedBy=multi-user.target

Start and enable service:

service perlwrapper start
systemctl enable perlwrapper

Setup nginx conf:

server {
    server_name po.domain.org.uk;
    root /var/www/po;

    error_log /var/log-sites/po-error.log;
    access_log /var/log/sites/po-access.log;

    location / {
        index index.html index.htm;
    }

    location ~ \.pl$ {
        gzip off;
        include /etc/nginx/fastcgi_params;
        fastcgi_pass unix:/var/run/fastcgi.sock;
        fastcgi_index index.pl;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }
}