Launch Ubuntu applications from a php script

[morleypotter]

Hi Everyone, I REALLY need some help please before I go mad.

 

As the subject of this post suggests i'm trying to launch Ubuntu applications from a php script, i have tried different ways of doing this but without much success.

 

Firstly i would like to explain why and maybe somebody may have a better suggestion or an alternative route...

 

I am making a 'personal' remix of Ubuntu which will be a live CD i can use for my university work (studying computer forensics), it will basically be a minimal install with every Linux based forensics application i can lay my hands on, instead of having a huge list of shortcut's in the menu's that ship with Ubuntu I though it would be fun/a challenge to make a fancy PHP based web site which contained a database of the programs so i could search through them and find what i need by category ect and then launch those applications from the same site.

 

I can 'talk' to Ubuntu through some small scripts i've tried but i can't launch any applications.

 

Here is what i've got so far....

 

<?php
echo "test1";
$launcher = shell_exec('ls'); 
print "<pre>$launcher</pre>";  

echo "test2";
$output = exec(ls);
$doit2 = exec($output);
print "<pre>$doit2</pre>";

echo "test3";
$cmd = 'ls';
echo "<pre>".shell_exec($cmd)."</pre>";
?>

 

Which outputs....

 

test1

 

index.php

webalizer

 

test2

 

Webalizer V2.01-10 (Linux 2.6.32-24-generic) locale: C

 

test3

 

index.php

webalizer

 

Sucess i thought, so i then tried using the same formats to launch nautilus as a test, all of the below produced no results...

 

<?php
echo "test1";
$launcher = shell_exec('/usr/bin/nautilus'); 
print "<pre>$launcher</pre>";  

echo "test2";
$output = exec(/usr/bin/nautilus);
$doit2 = exec($output);
print "<pre>$doit2</pre>";

echo "test3";
$cmd = '/usr/bin/nautilus';
echo "<pre>".shell_exec($cmd)."</pre>";
?>

 

Can anybody please help me out, i've searched all over these forums, php.net and googled endlessly.

 

Any advice would be greatly appreciated

 

Many thanks,

 

MorleyPotter

[trq]

Theoretically, if your Apache server user (the user Apache executes under) has the correct permissions this should be possible.

 

You would however need to make a $HOME directory for this user because allot of applications store data within hidden dirs within $HOME.

 

A better option might be to setup the suexec module for Apache, and have your users own there own versions of this 'site' interface. Then your server could execute commands as the user who owns the sites.

 

The entire problem is that websites run under the server, while applications need to run under indeveidual users.

 

I'd like to say this is simple to fix but its likely not unless you know a bit about Linux and Apache.

[morleypotter]

Hi Thorpe,

 

Firstly thank you for your help, i have read up on suEXEC which isn't (i think) the right tool for the job as there will only be one user on the live cd, [who i will probably make root as nothing can be written to a cd to break anything once i'm finished].

 

I have posted on ubuntuforums.org as well and what feedback i had from them suggests as you say it is theoretically possible, but nobody seems to actually know how to do it.

 

I'm now changing my train of thought and thinking of writing shell scripts to open the applications and using php to 'activate' the script - is this possible do you think?

 

Again thanks for your help.

[trq]

I'm now changing my train of thought and thinking of writing shell scripts to open the applications and using php to 'activate' the script - is this possible do you think?

 

It doesn't matter if you use shell scripts or not. PHP will do fine.

 

Given that your only going to allow one user on these systems, I would make Apache execute as this user. This should (in theory) solve the issue as Apache will be running as the same user who owns the desktop environment.

 

I wouldn't recommend them being root however as they can still quite easily damage filesystems on the machine.

 

[morleypotter]

It doesn't matter if you use shell scripts or not. PHP will do fine.

 

Given that your only going to allow one user on these systems, I would make Apache execute as this user. This should (in theory) solve the issue as Apache will be running as the same user who owns the desktop environment.

 

I wouldn't recommend them being root however as they can still quite easily damage filesystems on the machine.

 

Thanks again Thorpe, i have read somewhere that it is the normal practice to add the user to the www-data group, which i have done and re-ran the nautilus scripts above but nothing seems to be happening?

 

I fear i may miss understand?

 

Could you (or anyone willing) please advise on how I would make Apache execute as the current user?

 

Thanks.

[morleypotter]

Just a quick update on the code i'm using now (will this work once i've gotten Apache to run as the current user)

 

<?php
echo "test1"; // shell_exec can return results and print them
$launcher = shell_exec('ls -lart'); 
echo "<pre>$launcher</pre>";  

// now to try and launch an application

echo "Firefox launchtest1";
echo "</br>";
echo "</br>";
$launcher = exec('firefox'); 
if ($launcher == "1")
{
echo "working....";
}
else
{
echo "Firefox Launch Test 1 Failed!";
}
echo "</br>";
echo "</br>";
echo "Firefox launchtest2";
echo "</br>";
echo "</br>";
$output = `firefox`;
$doit2 = exec($output);
if ($doit2 == "1")
{
echo "working....";
}
else
{
echo "Firefox Launch Test 2 Failed!";
}
?>

 

Which produces....

 

test1

 

total 16

drwxr-xr-x  2 root root 4096 May 25 16:54 webalizer

drwxr-xr-x 16 root root 4096 May 25 16:54 ..

-rw-r--r--  1 root root  579 Aug 11 13:49 index.php

drwxr-xr-x  3 root root 4096 Aug 11 13:49 .

 

Firefox launchtest1

 

Firefox Launch Test 1 Failed!

 

Firefox launchtest2

 

Firefox Launch Test 2 Failed!

 

-- Thanks again.

[trq]

No.

 

As the manual says exec returns the last line of output resulting from the command. Its looks like your trying to check the commands status (which by the way will be 0 if successful). You'll want to look at the third arg to exec.

[morleypotter]

No.

 

As the manual says exec returns the last line of output resulting from the command. Its looks like your trying to check the commands status (which by the way will be 0 if successful). You'll want to look at the third arg to exec.

 

Hi Thorpe,

 

I changed the code and now it's reporting "working", so i assume that when i figure out how to give the sufficient rights to Apache it should launch the application?

 

OR

 

Because i added the 'if' statement to see if it was actually doing anything the code will now not launch the application?

 

Apologies if this doesn't make sense, i think i've confused myself now!  :-\

 

echo "Firefox launchtest2";
echo "</br>";
echo "</br>";
$output = `firefox`;
$doit2 = exec($output);
if ($doit2 == "0")
{
echo "working....";
}
else
{
echo "Firefox Launch Test 2 Failed!";
}
?>

[trq]

Surrounding a command in backticks executes it. I'm not sure why you are then trying to pass the output of that commands execution to the exec function.

[trq]

Oh and ps. The reason you are getting the working message is because exec must be returning false. 0 is the same as false in php. You will need to use the === operators to make sure you are actually getting the string "0".

[morleypotter]

Oh and ps. The reason you are getting the working message is because exec must be returning false. 0 is the same as false in php. You will need to use the === operators to make sure you are actually getting the string "0".

 

Thanks Thorpe, you are right it does now display "failed" as you suggest, as to why i thought it a good idea to pass it again to exec - i have no idea.

 

The code i have below therefore isn't even attempting to launch firefox, i have also added the /usr/bin path to it to see if that helps but nothing, oh well, i'll try some more googling to see how to give those rights to Apache.

 

I have just ran a echo exec('whoami'); the response being 'www-data' [which i understand is Apache] so i've done something wrong whilst trying to get Apache to run as the current user.

 

 

<?php
echo "Firefox Launch Test";
echo "</br>";
echo "</br>";
$output = `/usr/bin/firefox`;
if ($output === "0")
{
echo "working....";
}
else
{
echo "Firefox Launch Test Failed!";
}
?>

[trq]

On Debian (Ubuntu should be the same) you need to edit the /etc/apache2/envvars file to change the user & group Apache runs as. You'll then need to restart Apache.

 

sudo /etc/init.d/apache2 restart

[morleypotter]

Thanks Thorpe - Couldn't find that info anywhere, i was looking at suPHP when i noticed your post.

 

Here are the results of ps aux | grep apache which means i've changed it properly this time....

 

dave@dave-laptop:~$ ps aux | grep apache

root    14744  0.0  0.3  21344  6364 ?        Ss  15:18  0:00 /usr/sbin/apache2 -k start

dave    14747  0.0  0.1  21344  3644 ?        S    15:18  0:00 /usr/sbin/apache2 -k start

dave    14748  0.0  0.2  21800  5352 ?        S    15:18  0:00 /usr/sbin/apache2 -k start

dave    14749  0.0  0.2  21800  5328 ?        S    15:18  0:00 /usr/sbin/apache2 -k start

dave    14750  0.0  0.2  21800  5336 ?        S    15:18  0:00 /usr/sbin/apache2 -k start

dave    14751  0.0  0.1  21344  3656 ?        S    15:18  0:00 /usr/sbin/apache2 -k start

dave    14856  0.0  0.1  21344  3644 ?        S    15:18  0:00 /usr/sbin/apache2 -k start

dave    15116  0.0  0.0  3324  804 pts/0    S+  15:20  0:00 grep --color=auto apache

 

And my code which is this still doesn't work?

 

echo "Firefox Launch Test";
echo "</br>";
echo "</br>";
$output = `/usr/bin/firefox`;
if ($output === "0")
{
echo "working....";
}
else
{
echo "Firefox Launch Test Failed!";
}

 

I'm so frustrated i thought i was onto a winner when you told me how to change the user Apache runs as.

[trq]

Use shell_exec and take a look at what the command outputs.

[morleypotter]

Hi Thorpe, I tried it but it only made a blank line, when i change the word 'firefox' with 'ls' for example it then produces a result so i'm sure i've done it right?

 

<?php
echo "Firefox Launch Test";
echo "</br>";
$output = shell_exec('firefox');
echo "<pre>$output</pre>";
if ($output === "0")
{
echo "working....";
}
else
{
echo "Firefox Launch Test Failed!";
}
echo "</br>";
echo "whoami query = ";
echo (`whoami`);
?>;

[trq]

Well, use exec then but take a look at the manual and the extra arguments you can provide it.

[morleypotter]

Yeah, i tried that before, but it did the same thing, i have also read the manual but i'm not sure what other arguments to pass to it as i simply want it to open the application not do anything in particular?

[trq]

i have also read the manual but i'm not sure what other arguments to pass to it as i simply want it to open the application not do anything in particular?

 

You might want to read the manual entry again then. The optional arguments are explained. Both the second and third arguments are passed by reference meaning they can be accessed again from outside the function. The second arg is an array containing all output produced by the command. the third is the exit status.

[morleypotter]

I've made a small amount of progress amending an example on the manual page but i was wondering if anyone could 'tweak' this code to get it to work.

 

1st the code then the output.

 

<?php
exec('TERM=xterm display localhost:0.0 /usr/bin/firefox n 1 b i', $xterm, $error );
echo nl2br(implode("\n",$xterm));
if ($error){
    exec('TERM=xterm display localhost:0.0 /usr/bin/firefox n 1 b 2>&1', $error );
    echo "Error: ";
    exit($error[0]);
}
?>

 

Error: display: unable to open X server `' @ display.c/DisplayImageCommand/422.

 

I tried adding 'startx' in various places but it just makes the page hang?

 

Any help would be greatly appreciated.

[trq]

Do you know what startx actually does? Sorry, but if you want to do this, your going to need to do more investigating yourself.

[morleypotter]

well the error was: Error: display: unable to open X server `' @ display.c/DisplayImageCommand/422.

 

So i thought that i may need to start another x session which is why i tried 'startx'