CODEWITHSUNDEEP
phplinux
syrkull
syrkull

Reputation: 2344

Open Linux terminal command in PHP

I have a server running on Linux that execute commands to 12 nodes (12 computers with Linux running in them). I recently downloaded PHP on the server to create web pages that can execute commands by opening a specific PHP file.

I used exec(), passthru(), shell_​exec(), and system(). system() is the only one that returns a part of my code. I would like PHP to act like open termainal command in linux and I cannot figure out how to do it!

Here is an example of what is happening now (Linux directly vs PHP): When using linux open terminal command directly:

user@wizard:/home/hyperwall/Desktop> /usr/local/bin/chbg -mt

I get an output: 

The following settings will be used:
  option = mtsu   COLOR =    IMAGE = imagehereyouknow!
  NODES  = LOCAL
and additional code to send it to 12 nodes.

Now with PHP:

switch($_REQUEST['do'])
{ case 'test':
    echo system('/usr/local/bin/chbg -mt');
    break;
}

Output: 

The following settings will be used:
  option = mtsu   COLOR =    IMAGE = imagehereyouknow!
  NODES  = LOCAL

And stops! Anyone has an explanation of what is happening? And how to fix it? Only system displays part of the code the other functions display nothing!

Upvotes: 5

Views: 6926

Answers (8)

James Danforth
James Danforth

Reputation: 827

I am working on a project that uses Terminal A on machine A to output to Terminal B on Machine B, both using linux for now. I didnt see it mentioned, but perhaps you can use redirection, something like this in your webserver:

switch($_REQUEST['do'])
 { case 'test':
    #process ID on the target (12345, 12346 etc)
    echo system('/usr/local/bin/chbg -mt > /proc/<processID>/fd/1'); 
    #OR
    #device file on the target (pts/0,tty0, etc) 
    echo system('/usr/local/bin/chbg -mt > /dev/<TTY-TYPE>/<TTYNUM>');
    break;
 }

Definitely the permissions need to be set correctly for this to work. The command "mesg y" in a terminal may also assist...Hope that helps.

Upvotes: 0

Jammerx2
Jammerx2

Reputation: 864

PHP's system only returns the last line of execution:

Return Value: Returns the last line of the command output on success, and FALSE on failure.

You will most likely want to use either exec or passthru. exec has an optional parameter to put the output into an array. You could implode the output and use that to echo it.

switch($_REQUEST['do'])
{ case 'test':
    exec('/usr/local/bin/chbg -mt', $output);
    echo implode('\n', $output); // Could use <br /> if HTML output is desired
    break;
}

Upvotes: 2

Andras
Andras

Reputation: 3055

I wrote something a while ago that does just this -- you can run a command interpreter (/bin/sh), send it commands, read back responses, send more commands, etc. It uses proc_open() to open a child process and talk to it.

It's at http://github.com/andrasq/quicklib, Quick/Proc/Process.php

Using it would look something like (easier if you have a flexible autoloader; I wrote one of those too in Quicklib):

include 'lib/Quick/Proc/Exception.php';
include 'lib/Quick/Proc/Exists.php';
include 'lib/Quick/Proc/Process.php';

$proc = new Quick_Proc_Process("/bin/sh");
$proc->putInput("pwd\n");
$lines = $proc->getOutputLines($nlines = 10, $timeoutSec = 0.2);
echo $lines[0];
$proc->putInput("date\n");
$lines = $proc->getOutputLines(1, 0.2);
echo $lines[0];

Outputs

/home/andras/quicklib
Sat Feb 21 01:50:39 EST 2015

The unit of communication between php and the process is newline terminated lines. All commands must be newline terminated, and all responses are retrieved in units of lines. Don't forget the newlines, they're hard to identify afterward.

Upvotes: 1

greg_diesel
greg_diesel

Reputation: 3005

You are trying to change the backgrounds for currently logged in users... While they are using the desktop. Like while I'm typing this message. I minimize my browser and 'ooh my desktop background is different'. Hopefully this is for something important like it turns red when the reactor or overheating.

Anyway to my answer:

Instead of trying to remotely connect and run items as the individual users. Setup each user to run a bash script (in their own account, in their own shell) on a repeating timer. Say every 10 minutes. Have it select the SAME file.. from a network location /somenetworkshare/backgrounds/images/current.png

Then you can update ALL nodes (1 to a million) just by changing the image itself in /somenetworkshare/backgrounds/images/current.png

Upvotes: 1

BraveNewCurrency
BraveNewCurrency

Reputation: 13065

The other responses are good for generic advice. But in this specific case, it appears you are trying to change your background on your desktop. This requires many special considerations because of 'user context':

  • First, your web server is probably running as a different user, and therefore would not have permissions to change your desktop.

  • Second, the program probably requires some environmental variables from your user context. For example, X programs need a DISPLAY variable, ssh-agent needs SSH_AGENT_PID and SSH_AUTH_SOCK, etc. I don't know much about changing backgrounds, but I'm guessing it involves D-Bus, which probably requires things like DBUS_SESSION_BUS_ADDRESS, KONSOLE_DBUS_SERVICE, KONSOLE_DBUS_SESSION, and KONSOLE_DBUS_WINDOW. There may be many others. Note that some of these vars change every time you log in, so you can't hard-code them on the PHP side.

For testing, it might be simpler to start your own webserver right from your user session. (i.e. Don't use the system one, it has to run as you. You will need to run it on an alternate port, like 8080). The web server you start manually will have all the 'context' it needs. I'll mention websocketd because it just came out and looks neat.

For "production", you may need to run a daemon in your user context all the time, and have the web server talk to that daemon to 'get stuff done' inside your user context.

Upvotes: 2

Halayem Anis
Halayem Anis

Reputation: 7785

I think that the result of execution, can changes between users. First, try to run your PHP script directly into your terminal php yourScript.php
If it runs as expected, go to your Apache service and update it to run with your own credentials

Upvotes: 1

madz
madz

Reputation: 1873

My First thought is it can be something about std and output error. Some softwares dump some informations on std out and some in std error. When you are not redirecting std error to std out, most of the system calls only returns the stdout part. It sounds thats why you see the whole output in terminal and can't in the system calls. So try with 

 /usr/local/bin/chbg -mt 2>&1

Edit: Also for a temporary work through, you can try some other things. For example redirect the output to file next to the script and read its contents after executing the command, This way you can use the exec:

exec("usr/local/bin/chbg -mt 2>&1 > chbg_out");
//Then start reading chbg_out and see is it work

Edit2 Also it does not make sense why others not working for you. For example this piece of code written in c, dumps a string in stderr and there is other in stdout.

#include <stdio.h>
#include<stdlib.h>
int main()
{

    fputs("\nerr\nrro\nrrr\n",stderr);
    fputs("\nou\nuu\nuttt\n",stdout);
    return 0;
}

and this php script, tries to run that via exec:

<?php

exec("/tmp/ctest",&$result);

foreach ( $result as $v )
{
echo $v;
}
#output ouuuuttt
?>

See it still dumps out the stdout. But it did not receive the stderr. Now consider this:

<?php

exec("/tmp/ctest 2>&1",&$result);

foreach ( $result as $v )
{
    echo $v;
}
//output: errrrorrrouuuuttt
?>

See, this time we got the whole outputs.

This time the system:

<?php
     echo system("/tmp/ctest 2>&1");
     //output: err rro rrr ou uu uttt uttt
?>

and so on ...

Upvotes: 4

renskiy
renskiy

Reputation: 1400

Maybe your chbg -mt writes additional code to stderr instead of stdout? Try to execute your script inside php like this:

/usr/local/bin/chbg -mt 2>&1

Upvotes: 2

Related Questions