Issue PHP upload fails with "File upload error - unable to create a temporary file" after CentOS 7 update

[SteveITS]

Server is CentOS Linux release 7.9.2009 (Core). A web site uploads a CSV file for import. I am told it worked approximately Jan. 20. On Jan. 27 we installed CentOS updates. As the server admin I made no other recent changes and Plesk updated in early January. This week when the user tried to import it logged:

[Tue Feb 02 08:15:12.000066 2021] [proxy_fcgi:error] [pid 2759:tid 140256493913856] [client x.x.x.x:48434] AH01071: Got error 'PHP message: PHP Warning: File upload error - unable to create a temporary file in Unknown on line 0\n', referer: https://server/import.php

In the PHP settings for the web site if I set "upload_tmp_dir=/tmp" then the upload works.

Per Zend, PHP should use the system tmp dir if unset. Since there was no code changes on this site, I am confused why it would stop working. The site is old so it is using PHP 5.6 (yes I know) so PHP was not updated last month.

Has anyone else seen this? Or have any idea why it would start happening?

 

[IgorG]

I suppose that cleaning up /tmp folder during system update resulted in the fact that /tmp for the PHP-FPM does not exist.
You have to restart the PHP service used by the domain. This will recreate the temporary folder in /tmp:

# service plesk-phpXX-fpm restart

 

[SteveITS]

Hi Igor, I see... I didn't get that far, but if I remove "upload_tmp_dir = /tmp" the upload works. So likely you are correct that adding the setting would have restarted the site and/or PHP.

So is the default for Plesk+PHP FPM the /tmp/systemd-private-7441f87e6af24cb2a6d3c32345887352-plesk-php56-fpm.service-lnbmT1/tmp/ directory?

Edit: if I show the output, PHP ($_FILES["csvfile"]["tmp_name"]) says the file is uploaded as /tmp/phpEyDC8h, not the above directory.

 

[Bitpalast]

"/tmp/phpEyDC8h" is session related. In other sessions it will have a different name.

 

[SteveITS]

"/tmp/phpEyDC8h" is session related. In other sessions it will have a different name.

Hmm, so why did it fail until I put in that setting and (apparently more importantly) triggered a PHP restart? /tmp did exist of course. Unless something disconnected the running PHP process from tmp? Or it uses the longer path and moves the file into /tmp? (inquiring minds want to know...)