PHP Programming - Problem to launch a program with system()

Author

Problem to launch a program with system()

sylsau

2006-04-28, 7:59 am

Hello,

I wrote a JAVA program which uses the JAVA API JDOM 1.0 (of this site
www.jdom.org)
I put the archive jdom.jar in the directory /usr/share/java/jdom.jar
and I added this path in the CLASSPATH variable.
The program runs normally when I launch it in a unix shell.

Now, I want to launch this JAVA program in a PHP program with system()
function for example. I have an apache server with PHP 4 who runs. The
variable safe_mode of PHP is at off. So, the program PHP can launch
executable program.

But, It doesn't because of CLASSPATH problem I think. So, to understand
where is the problem I recuced my programs and this is the 2 programs :

- program JAVA :

import java.io.*;
import org.jdom.*;
import org.jdom.input.*;

class TestSAX{

TestSAX()
{

}

void instanciateSAXBuilder()
{
//On cr=E9e une instance de SAXBuilder
try{
SAXBuilder sxb =3D new SAXBuilder();

System.out.println("Constructeur de SAX");

}catch(Throwable e){

e.printStackTrace();
}
}

}

public class Test {
public static void main (String[] args) {

PrintStream ps =3D null;

try{

ps =3D new PrintStream("./test.txt");

}catch(Exception e){

e.printStackTrace();

}

System.setOut(ps);
System.setErr(ps);
System.out.println("test");

try {
System.out.println("Step 1");
TestSAX ts =3D new TestSAX();
System.out.println("Step 2");
ts.instanciateSAXBuilder();
System.out.println("Step 3");
} catch (Throwable t) {
System.out.println("FAILED");
t.printStackTrace();
}

}

}

- program PHP

<?php

$line =3D system("/usr/bin/java -cp /usr/share/java/jdom.jar Test",
$retval);
echo"Statut : ".$retval;

?>

On my computer, apache runs on the user www-data. And i tried to
execute my program JAVA on this user and it runs normally. Besides, the
CLASSPATH of the user www-data contain the path to jdom.jar

This is the error message (contained in the file test.txt) after the
execution of the PHP program :

test
Step 1
FAILED
java.lang.NoClassDefFoundError: org/jdom/input/SAXBuilder
at Test.main(Test.java:51)

So, it seems that the program doesn't find the SAXBuilder class what it
wants to tell that the CLASSPATH is not good when PHP launch the
program JAVA. But, I put the option -cp by launching the JAVA program
in the PHP program so the CLASSPATH put in this option should be good.

To be sure that this option could run, I made the following PHP program
:

$line =3D system("/usr/bin/javac Test.java", $retval);

After that, it doesn't compile the program. So, I tried that :

$line =3D system("/usr/bin/javac -cp /usr/share/java/jdom.jar Test.java",
$retval);

And there, the program is normally compiled !
So, it's strange that here the CLASSPATH runs and in the other example
it doesn't run.

Somebody will have and idea about modifications that I can do on the
programs ?

Thanks to help me.

Sylvain

Colin McKinnon

2006-04-30, 6:59 pm

sylsau wrote:

> Hello,
>
> I wrote a JAVA program which uses the JAVA API JDOM 1.0 (of this site
> www.jdom.org)
> I put the archive jdom.jar in the directory /usr/share/java/jdom.jar
> and I added this path in the CLASSPATH variable.
> The program runs normally when I launch it in a unix shell.
>
> Now, I want to launch this JAVA program in a PHP program with system()
> function for example. I have an apache server with PHP 4 who runs. The
> variable safe_mode of PHP is at off. So, the program PHP can launch
> executable program.
>

<snip>
> On my computer, apache runs on the user www-data. And i tried to
> execute my program JAVA on this user and it runs normally. Besides, the
> CLASSPATH of the user www-data contain the path to jdom.jar
>
> This is the error message (contained in the file test.txt) after the
> execution of the PHP program :
>
> test
> Step 1
> FAILED
> java.lang.NoClassDefFoundError: org/jdom/input/SAXBuilder
> at Test.main(Test.java:51)
>

So check the CLASSPATH environment variable from within PHP. If its not
there. set it before running your java prog.

C.

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