Question 254508 in Ubuntu Question posted in
The official Ubuntu documentation can be found here.

The shell_exec and exec() commands don't work on linux Ubuntu in my localhost Ububtu 20.04

The following code only works in my Terminal but it doesn’t work in my localhost xampp linux Unbuntu 20.04, Both shell_exec() and exec() don’t work. When I go to localhot it executes all the code but not its two functions. The following code does not execute.

// Add the --enable-local-file-access option to enable access to local files (HTML)
$wkhtmltopdfCommand = "wkhtmltopdf --enable-local-file-access {$outputHtmlPath} {$pdfOutputPath}";
shell_exec($wkhtmltopdfCommand);

I don’t know if I need to change anything for this to work, but I need some advice.

Tags:

2

Answers


  1. 0

    1) Check the security setup

    Did you check and compare the php.ini settings between web and CLI?

    In your script, add this at the beginning:

    phpinfo();
die();

    Run your page and check the settings applied at execution. You’ll
    also see which php.ini files are read and applied.

    The problem is that shell_exec() and exec() are probably disabled
    for security reasons. This can be changed by editing
    PHP’s disable_functions option.

    INI settings are usually stored in specific *.ini files under the
    /etc/php/* directories. So you have to look for some settings
    in there. Typically, if you have PHP 8.2 running over FPM then
    you have to check /etc/php/8.2/fpm/php.ini.

    My /etc/php/8.2/cli/php.ini file has disable_functions set to an
    empty string, meaning that in command line there’s no restriction.
    But in my FPM settings, I have a huge list of critical functions
    which are disabled to reduce the risk of having my server hacked.

    Apache configuration can also set some
    PHP settings    ,
    just for a specific Virtual Host. So have a look at them if you can’t
    find something in the php.ini files.

    Depending on your PHP setup, you may also have to check
    safe_mode
    and
    suhosin.executor.* if you have the Suhosin hardening module installed.

    2) Use a full path to the binary

    When shell_exec() is run from the web server, I think that
    it’s rather common that the binary isn’t found in the PATH.

    Open a console and run

    which wkhtmltopdf

    This should output the full path to the binary. Certainly something
    such as /usr/bin/wkhtmltopdf.

    Now replace your PHP code with the full path to the binary:

    // Add the --enable-local-file-access option to enable access to local files (HTML)
$wkhtmltopdfCommand = "/usr/bin/wkhtmltopdf --enable-local-file-access {$outputHtmlPath} {$pdfOutputPath}";
shell_exec($wkhtmltopdfCommand);
    Login or Signup to reply.
  2. 0

    Instead of

    shell_exec($wkhtmltopdfCommand);

    try

    $result = passthru($wkhtmltopdfCommand . ' 2>&1');
var_dump($result);

    and it should tell you what’s wrong.

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search