How to implement such a function in PHP? - php

It should test if a specific port is open on localhost,if not,reboot.
It's run in windows.

This should do it, tested on Windows 7 and working. Should work on all NT flavours:
function testPort($port, $timeout = 5) {
if(!fsockopen('127.0.0.1', $port, $errno, $errstr, $timeout)) {
exec("shutdown.exe /r");
}
}
testPort(8080);

You can write a PHP extension to do that. Extension should use Windows API to reboot the machine because the socket checking part can be done straight in PHP. Here is a question on how to write extensions.
InitiateSystemShutdown is the Win32 API function you can call to do the actual rebooting.

Use sockets
you need to open a TCP connection (socket) to the localhost with that specific port. If the connection is establish, it means the port is open, otherwise (if timed-out or rejected), then the port is closed.
that's only for TCP ports
here's a sample code
For the 'reboot' part, use exec('shutdown -r');

Related

How to create a persistant php listening server

I have some embedded devices which connect to their sever (supplied software for windows) running on port 6000.
I'm confused as to how this works as my understanding is that when a tcp connection is made on a port, that's it, the port is occupied an no other connections can be made.
But I guess this logic is wrong as multiple devices can connect to their server software just as a web server can accept multiple connections on port 80.
When I run netcat on an ubuntu server with the command nc -l -k 6000 it seems to do what I want, I can see the messages coming in one after another from multiple devices.
From the netcat manual:
-k Forces nc to stay listening for another connection after its cur-
rent connection is completed. It is an error to use this option
without the -l option.
I tried to achieve a similar scenario with php but I failed. Here's what I have so far:
<?php
$address = "0.0.0.0";
$port = 6000;
$mysock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_bind($mysock, $address, $port) or die('Could not bind to address');
socket_listen($mysock, 5);
$client = socket_accept($mysock);
while (true) {
$input = socket_read($client, 1);
echo $input;
}
?>
I can see the first message from the first device that connects but after that nothing. Also this seems to be the wrong approach as the while loop causes high cpu usage.
Note I'm running the php script at the command line on an ubuntu server.
I realize that this code will only accept one client, but how can I change it so that it will behave like nc and accept multiple connections. Sorry if the question seems vague, I really don't know where to begin. Any help is appreciated

how to use php sockets to write string

So Im trying to get my head wrapped around this....
I open the port
$remip = $_SERVER['SERVER_ADDR']; //Grab my server address
$fp = fsockopen($remip, 80, $errno, $errstr, 10);//Godaddy hosting only 80 and 443 ports work
//fsockopen(ip address , port, IDK, IDK, timeout delay)
so now the ports open or if not maybe some error checking to be sure
if (!$fp) { echo "$errstr ($errno)<br>\n"; exit; } //Not sure what this echos out but its clear how it stops errors
So now that the port is open any ip/client can connect on this port????
Ill assume I can now connect....
So on my client I open a socket to my server ip address port tcp connection.....
The php file includes something like
else {$out = "hello, 80\r\n"; //out specifies the string to be written , bytes to write
fwrite($fp, $out); //$fp is the handle
fclose($fp)}//close the connection
at this point ill assume that my client gets the hello written to it ..
finish up by closing the connection
Im entirely new to this so Im attempting to understand some sample code here...
So how long is this socket open for? If i want to keep this port open do i need to do a cron job to launch this file periodically.
Im 100% sure that I have got something wrong here so please set me straight.
I think you have a misconception of what fsockopen does. In your example your fsockopen does not actually open port 80 (as in opening a server socket), but it opens a client socket that connects to port 80 on the server itself. It actually does open a (client) port which gets a (not completely) random number.
After you connected using fsockopen you can send HTTP commands to the webserver such as GET /index.php
What you need to use is socket_listen() and socket_bind(). There are a few places in the docs that show you how to get PHP listening on a socket: http://www.php.net/manual/en/function.socket-listen.php
I suggest you read and try them out by simply testing then with a unix tool called netcat (nc <ip_address> <port> command normally)

Fetch file from https only server

I have a small script which uses curl and retrives specific contents from a defined url. I had this tested on my localhost and it worked.
Now I have to retrive data from a HTTPS-only website (plus, the certificate is invalid, but I know the owners) from my free hosting, but the myserver neither supports CURL nor file_get_contents("https://other-server.com") function. By the way, http://other-server.com isn't accesible.
Is there any method to fetch a file from this server using the HTTPS port, but with HTTP protocol? Or is there some method to use HTTPS, altough my server doesn't support it? (It isn't my server, I haven't access to its configuration)
Try this:
<?php
$fp = fsockopen("ssl://other-server.com", 443, $errno, $errstr);
if(!$fp) die($errno. " : " . $errstr);
$send =
"GET / HTTP/1.0\r\n".
"Host:other-server.com\r\n".
"Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n".
"\r\n";
fwrite($fp, $send);
while(!feof($fp)) {
echo fread($fp, 512);
}
?>
Should you run into 'ssl transport not available error message', see Socket transport "ssl" in PHP not enabled
If your host is external and perhaps a free webhosting service, you are fresh out of luck.. Best option would be to figure out which webhosts has the SSL transport enabled - otherwise the working with HTTPS protocol simply will not comply.
Your last 'out' is to try to load extension into PHP language dynamically. You will need the excact extension (dll/so) which matches
the PHP version on host (see phpinfo).
the CPU architechture of host (unix, see passthru("cat /proc/cpuinfo");), e.g. amd64,i386..
the OS 'layout', .dll is for a windows host (IIS etc) and .so for UNIX.
Funcition to use is dl aka dynamic-link to load the library. For windows host, you will need php_openssl.dll and php_sockets.dll - and in turn for UNIX, OOops - you would need to recompile php core..
Happy hacking :)
php-man-pages

Port checking from php

I'm trying to connect to gmail pop server from a phplist installation and it fails, but i'm not sure whether my webhost opened port 995 or not. They say they have opened it, but i'm in doubt. Is there a way i can check it from a php script? They are running php 5.2.0 on a windows server, though i'm not sure what OS is that. phpinfo() says "Windows NT DEDI514 5.2 build 3790"
You can put code in a php script to open a connection to a specific hostname (or IP address) and port.
If you know the expected response, you should be able to tell if you are getting a connection. If you get something like "Connection refused", then either you are being blocked, or the destination host is not accepting connections on that port.
This example uses IP address 192.0.2.0 and port 995. Replace these with whatever you want to test.
<?php
echo "\nOpening connection\n\n";
$fp = fsockopen("192.0.2.0", 995, $errno, $errstr);
if (!$fp) {
echo "ERROR: $errno - $errstr\n";
} else {
echo fread($fp, 1024);
fclose($fp);
}
?>
You can also send data to the server using
fwrite($fp, "blah blah blah\r\n");
There is more information about fsockopen here.
I think you'll need to ping or traceroute to a machine that will respond on that port.
This article should have much more than you want to know, but there's an example script at the bottom that you can modify to test.
http://www.planet-source-code.com/vb/scripts/ShowCode.asp?lngWId=8&txtCodeId=1786
There are some other scripts here:
http://www.theworldsend.net/
I can't vouch for any of these personally, but they look like what you need.
And, of course, if you can ssh or telnet into your server, you can do all this much more easily using the ping and traceroute commands.
Maybe safe mode is active? This prevents calling services on other servers.
Edit:
All filesystem and stream functions are affected by the safe mode settings!
The open_basedir setting affects fopen()!

php fsockopen

I have a simple php script on a server that's using fsockopen to connect to a server.
<?php
$fp = fsockopen("smtp.gmail.com", 25, $errno, $errstr, 30);
if (!$fp) {
echo "$errstr ($errno)<br />\n";
} else {
echo fgets($fp, 1024);
fclose($fp);
}
?>
The problem is the the script times out and fails to connect. If i change the port from 25 to 80 for example it works without problems on any host. So the problem seems to be only the port 25 no matter what host i use, i tried a lot of them and all work for port 80 and others but for 25 fails.
Connections are not blocked form firewall as if i telnet from shell it successfully connects to any port on any host.
Any idea what could be the problem as it's really weird?
LE: If i run the same php script from the shell, php scriptname.php it works so only when i run it by http it fails. I have apache with SuPHP so the problem is around here somewhere
Interesting...
Some firewalls can block specific program's connections to specific ports.
Please check it again, try to stop firewall completely. Also try to stop any anti-spyware.
Like maxnk mentioned firewalling is the most likely issue, either on the server, or by your ISP. Port 25 is frequently firewalled as a method to prevent spam.
Just as a quick test, since you mentioned gmail, you might want to try connecting to port 587 instead. Gmail listens for smpt on this alternate port in addition to port 25 to help users bypass overly restrictive firewalls.
I've run into some strange issues with PHP's socket handling, too. It ended up being a problem with the system it was running on. Have you tried running your code on a different machine?
I think the connection problem is with your machine. I just copied your code into a script on my machine(linux suse) and ran it with php -f test_script. I got the following message
220 mx.google.com ESMTP j8sm1814228gvb.0
CentOS can have SELinux enabled which can cause connection weirdness. Have you checked your error logs?

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