Use PHP to run a shell script

Question

Now I know this question has been asked a few times, but I've followed everyone's suggestions and I'm still stumped.

I have a shell script (/var/www/scripts/test.sh):

ssh_con="[email protected]"
key="/home/user/.ssh/key"

echo "export start"
ssh -i $key $ssh_con "php /file/location/ service:batch:job export --env=prod"
echo "export complete"

the script has the following permissions:

-rwxrwxrwx 1 www-data     www-data     1792 Jun  3 10:44 bash_script.sh*

the code im running in php is:

try { 
$outbuf=shell_exec("sh /var/www/scripts/test.sh");
echo "<pre>".$outbuf."</pre>";

}catch (Exception $e) { //while an error has occured
echo "==> Error: ".$e->getMessage();
exit();
}

When I view this from a web browser I get:

export start
export complete

However, ssh does not run.

I can confirm that php.ini allows exec and shell_exec.

I feel like I'm missing something obvious.

Try putenv("PATH", "/bin:/usr/bin:/usr/local/bin:/sbin:/usr/sbin"); before you call shell_exec();. — Will
– Will, Commented Jun 3, 2016 at 5:13
Which user is your php run at. Does it have permission to your shell script? — weigreen
– weigreen, Commented Jun 3, 2016 at 5:22

miken32 · Accepted Answer · 2016-06-03 05:39:31Z

Since your script is already executable, you should call it directly. Just put a shebang on top and you've removed one layer of complication.

Next, redirect standard error from ssh to standard output so that PHP can show you any error messages.

I'd be willing to bet that you'll find ssh is complaining about the key. You'll need to put that key file somewhere else. An SSH key in a user directory typically has 600 permissions.

Finally, shell_exec() won't throw anything you can catch. If you want to know if the process succeeded, you can use a different function. In that case it might be a good idea to pass on the exit status that matters.

So, to sum up:

#!/bin/sh
ssh_con="[email protected]"
key="/home/user/.ssh/key"

echo "export start"
ssh -i "$key" "$ssh_con" "php /file/location/ service:batch:job export --env=prod" 2>&1
ssh_result=$?
echo "export complete"
exit ssh_result

And then:

<?php
exec("/var/www/scripts/test.sh", $outbuf, $result);
$outbuf = htmlspecialchars(implode("\n", $outbuf));
echo "Exited with code $result.";
echo "<pre>$outbuf</pre>";

I forgot about the permissions on the key, I think this could be the correct answer.
@Mike good to hear, you should look at the other changes suggested as well, they will make your system much more robust.
I implemented all the changed you suggested. I also changed the permission of the scripts so they are only executable by the www-data group.

Will · Accepted Answer · 2016-06-03 05:17:03Z

0

More than likely, the script isn't executing properly because environment variables that are present in your terminal session may not be when run via PHP. So calling ssh or php without them being present in $PATH will not work.

Try running this immediately before your call to shell_exec():

putenv("PATH", "/bin:/usr/bin:/usr/local/bin:/sbin:/usr/sbin");

answered Jun 3, 2016 at 5:17

Will

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