PHP exec(): Running bash script to configure environment then executing Python program

Question

Shell is tcsh. PHP v5.1.6. Redhat 5.7. Safe_mode is OFF.

Running php script from the browser using exec to:

1. configure environment via source command on bash script
2. run a python program relying on the environment set up by the bash script (program outputs to STDOUT)

This works from the command line ($shell = tcsh):

/bin/bash -c "source /path-to-config-bash-script/config.sh; /bin/path-to-python /path-to-python-program/prog.py 2>&1"

This does not. Python program returns an error indicating that the environment is not set up correctly (can't find certain libraries, etc.):

<?php
....
$cmd = "/bin/bash -c \"source /path-to-config-bash-script/config.sh; /bin/path-to-python /path-to-python-program/prog.py 2>&1\"";
$ret_val = exec( $cmd, $ret_arr, $err );
?>

Quadruple-checked permissions and everything looks OK.

Thanks!

Answer 1

Four things to note.

1 - PHP must not have safe_mode on to leverage exec()

2 - The shell script script needs to have #!/bin/bashto be declared at the top of the file rather than being passed into the exec()

3 - The python script must have #!/usr/bin/python at the top of the script rather than attempting to execute it through the exec() statement.

4 - All directories that are traversed to get to the script must be readable.

So the final should look like:

$cmd = "/path-to-config-bash-script/config.sh; /path/to-python/program/prog.py 2>&1";

This should resolve all your issues.