PHP isn't able to read file - php

Question

I'm stuck trying to open a file with fopen in php.
$db_ausgaenge = "statuseing.php";
$dout = fopen($db_ausgaenge, "x+");
print $dout;
print(shell_exec('whoami'));
print(shell_exec('pwd'));
print(shell_exec('id'));
fwrite($dout, $out);
fclose($dout);
Warning: fopen(statuseing.php): failed to open stream: File exists in /var/www/html/zufallsgenerator.php on line 33
I checked following items:
chmod for statuseing.php 0777
owner is www-data with groud www-data
script is running as user www-data
groups are uid=33(www-data) gid=33(www-data) groups=33(www-data)
pwd is /var/www/html as expected
the path the scripts want's to open is correct
checked openbase dir in php.ini showed in phpinfo(), added /var/www/html, but php doesn't care about it.
open_basedir = /var/www/html/
After daemon-reload and restarting apache2 via systemctl nothing changed, phpinfo() didn't show the path given in the config. restarting the system via init 6 didn't took effect, too.

Answer 1

statuseing.php already exists.
See the manual (http://php.net/manual/en/function.fopen.php) - opening in x or x+ mode says: Create and open for writing only; place the file pointer at the beginning of the file. If the file already exists, the fopen() call will fail by returning FALSE

Answer 2

Look at the mode you are using.
x+ means that if the file already exists an error will be thrown.
To find the correct mode depending on your scenario check out http://php.net/manual/en/function.fopen.php

Answer 3

Try this:
$db_ausgaenge = __DIR__."/statuseing.php";
$dout = fopen($db_ausgaenge, "a+"); // x+ will throw error cuz it tries to open existing file, thx to: bluegman991 (;
print(shell_exec('whoami'));
print(shell_exec('pwd'));
print(shell_exec('id'));
fwrite($dout, $out);
fclose($dout);
or if You want to truncate file before adding data use w+:
$db_ausgaenge = __DIR__."/statuseing.php";
$dout = fopen($db_ausgaenge, "w+");
print(shell_exec('whoami'));
print(shell_exec('pwd'));
print(shell_exec('id'));
fwrite($dout, $out);
fclose($dout);
also do some checkups:
1) check free space: df -h
2) check if You can edit that file: nano /var/www/html/statuseing.php