Executing java via exec or shell_exec gives error

Question

I have jdk1.7.0_07 installed on server(linux). The file permission to ~/bin files are executable(755). However when I tried to execute,

$output = exec("/usr/java/jdk1.7.0_07/bin/java -version 2>&1");
echo $output;

It gives permission denied error, I have tried this,

$output = exec("java -version 2>&1");
echo $output;

Which gives command not found error. While checking my environment variables. I have succesfully added JAVA_HOME = /usr/java/jdk1.7.0_07 and for PATH = /usr/java/jdk1.7.0_07/bin

But,

When I run above mentioned PHP script it keeps giving me those permission denied or command not found error. Any personal experience or clue?

Answer 1

If you are running these commands from the command-line, you probably execute them with your own user permissions. However, when you execute these same commands via a PHP script in a web app, they will be executed with the Apach user (typically www-data) permissions. These means that you cannot rely on the command-line output to debug permission errors unless you can log in as the exact same user that runs your PHP script.