Deleting a file through cli in vagrant give permission denied - php

Question

I'm trying to run a php script from the command line in vagrant, but I'm getting a permission denied error when trying to delete a file.
Using the command sudo chmod 777 messages/ does not work, because I can't change the directory permissions, vagrant's shared folders don't allow that.
I also tried to use chmod and umask to change the directory's and file's permissions to be able to delete it, but to no avail.
$oldUMask = umask(0000);
chmod($dir, 0777);
chmod($file, 0777);
unlink($file);
umask($oldUMask);
How can I fix this? Am I missing something obvious?
The directory structure is like so:
/vagrant
/app
/messages
And the owner and group of the directory is www-data, vagrant is run with those user and group settings aswell.
This is the complete script:
<?php
require 'cli-start.php';
use CodeRichard\Config\Config;
use CodeRichard\Text\MessageInfo;
use CodeRichard\Text\TextMessage;
$dir = 'messages/';
$iterator = new DirectoryIterator($dir);
$file = null;
/** #var SplFileInfo $entry */
foreach($iterator as $entry)
{
$ext = $entry->getExtension();
if($entry->isDir() || strtolower($ext) != 'json')
{
continue;
}
$file = $entry->getRealPath();
break;
}
if($file != null)
{
$message = json_decode(file_get_contents($file), true)['message'];
$service = new Services_Twilio(Config::get('twilio.account_sid'), Config::get('twilio.auth_token'));
$messageInfo = new MessageInfo(Config::get('twilio.from_number'), Config::get('twilio.to_number'), $message);
$textMessage = new TextMessage($service, $messageInfo);
$status = $textMessage->send();
if($status['sent'])
{
$oldUMask = umask(0000);
chmod($dir, 0777);
chmod($file, 0777);
unlink($file);
umask($oldUMask);
}
echo $status['message'];
}

Answer 1

The known problem. The simplest solution is to modify in the Vagrantfile the synced folders settings:
config.vm.synced_folder "./htdocs", "/var/www", owner: "vagrant", group: "www-data", mount_options: ["dmode=775,fmode=664"]