Lighttpd

Hello
Please excuse this long text but it is a complex problem.

I experience that fopen($url) and stream_get_contents() is hanging. And I need help to narrow down the problem
I suspect it to be some kind of resource depletion / timeout / semaphore - when a web-server calls itself.

But I need an indication where to look. Any kind of help is appreciated.

It has been working flawlessly with a previous version (lighttpd 1.4.19)

It is an embedded system with multiple computers with static IP addresses, all computers have a web-server.
One of them is the designated "master web-server"

Say the IP net is "192.168.2.255" - the master web-server is always found at IP_net.199 ( that is 192.168.2.199)
each computer (all slaves AND the master) is expected to have a web-server at .10n (in this case 192.168.1.101)

So the Master web-server service two IP addresses (.199 and .101)
the external world (web browsers) always talk to the Master at .199.
main functionality is to concatenate a number of json files from all "slave URLs" (including its own .101 address)

So the web-server "calls" it self. It works well for 1 or 2 iterations - then something looks up and I get loong hangs.

Kind regards Lars

in a web-browser pointed at http://192.168.2.199
pseudo java script
while (true) {
ajax(GET, http:192.168.2.199/get_allvalues.php);
wait( 0.5 second)
}

get_allvalues.php: (real code attached ) but here is the loop, in pseudo code

    for ($i= 1; $i <max;$i++)
    {
    $handler = @fopen('http://192.168.2.10' . $i . '/progdir/parms.json','r') ;
      if ($handler != FALSE) {
      $a =stream_get_meta_data($handler);
      $filecont =$filecont. stream_get_contents($handler,$a["unread_bytes"]) ;
      fclose($handler) ;
      $a=0; }
    $handler = @fopen('http://192.168.2.10' . $i . '/progdir/errorstate.json','r') ;
      if ($handler != FALSE) {
      $a =stream_get_meta_data($handler);
      $filecont =$filecont.stream_get_contents($handler,$a["unread_bytes"]) ;
      fclose($handler) ;
      $a=0; }
    $handler = @fopen('http://192.168.2.10' . $i . '/progdir/errorstate.json','r') ;
      if ($handler != FALSE) {
      $a =stream_get_meta_data($handler);
      $filecont =$filecont.stream_get_contents($handler,$a["unread_bytes"]) ;
      fclose($handler) ;
      $a=0; }
    }
  print ($filecont)

misc. version details

#uname -a
Linux Computer-2-MASTER 4.1.17-yocto-standard #1 SMP PREEMPT Thu Nov 3 09:45:23 CET 2016 i686 GNU/Linux

#lighttpd -v
lighttpd/1.4.36 (ssl) - a light and fast webserver
Build-Date: Nov 23 2016 10:44:12

1. php-cgi -v
   PHP 5.6.25 (cgi-fcgi) (built: Nov 10 2016 13:44:39)
   Copyright (c) 1997-2016 The PHP Group

#ifconfig
eth0 Link encap:Ethernet HWaddr 08:00:27:1E:70:01
inet addr:192.168.2.12 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fe1e:7001/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:13647 errors:0 dropped:92 overruns:0 frame:0
TX packets:46945 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1361632 (1.2 MiB) TX bytes:6937764 (6.6 MiB)

eth0:0 Link encap:Ethernet HWaddr 08:00:27:1E:70:01
inet addr:192.168.2.101 Bcast:192.168.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

eth0:1 Link encap:Ethernet HWaddr 08:00:27:1E:70:01
inet addr:192.168.2.199 Bcast:192.168.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

eth0:2 Link encap:Ethernet HWaddr 08:00:27:1E:70:01
inet addr:192.168.2.211 Bcast:192.168.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1