Perl + FastCGI + nginx

#!/usr/bin/perl

use FCGI;
use FCGI::ProcManager; #!!!
use Socket;
use POSIX qw(setsid);
require 'syscall.ph';

my $PROCESSES = 100;

#&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 {
	$proc_manager = new FCGI::ProcManager({ n_processes => $PROCESSES, die_timeout => 10 }); #!!!
        $socket = FCGI::OpenSocket( "/var/run/nginx/perl_cgi-dispatch.sock", 10 ); #use UNIX sockets - user running this script must have w access to the 'nginx' folder!!
        $request = FCGI::Request( \*STDIN, \*STDOUT, \*STDERR, \%req_params, $socket );
        if ($request) { request_loop()};
        FCGI::CloseSocket( $socket );
}

sub request_loop {
	$proc_manager->pm_manage();
        while( $request->Accept() >= 0 ) {
           $proc_manager->pm_pre_dispatch(); #!!!
           #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 - Executing $req_params{SCRIPT_FILENAME} failed !\n";                        
		}
		else {
		   if ($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 ( keys %req_params){
        	           $ENV{$_} = $req_params{$_};
                	}
        	        # 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 exist or is not executable by this process.\n";
            }
            $proc_manager->pm_post_dispatch(); #!!!
        }
}