Arch Linux

Description:
PostfixAdmin throws an error message :
Dec 03 11:23:15 computer systemd[1]: Starting The PHP FastCGI Process Manager...
Dec 03 11:23:16 computer php-fpm[1037]: [ERROR] unable to bind listening socket for address '/run/postfixadmin/postfixadmin.sock': Permission denied (13)
Dec 03 11:23:16 computer php-fpm[1037]: [ERROR] FPM initialization failed
Dec 03 11:23:16 computer php-fpm[1037]: [ERROR] unable to bind listening socket for address '/run/postfixadmin/postfixadmin.sock': Permission denied (13)
Dec 03 11:23:16 computer php-fpm[1037]: [ERROR] FPM initialization failed
Dec 03 11:23:16 computer systemd[1]: php-fpm.service: Main process exited, code=exited, status=78/CONFIG
Dec 03 11:23:16 computer systemd[1]: php-fpm.service: Failed with result 'exit-code'.
Dec 03 11:23:16 computer systemd[1]: Failed to start The PHP FastCGI Process Manager.

Additional info:
* PHP, PHP-FPM, PHP-IMAP 7.4.0-2
* PostfixAdmin 3.2.3-1
* Postfix 3.4.8-1
* MariaDB 10.4.10-2

Steps to reproduce:
* Install all dependancies
* Follow the wiki to install PostfixAdmin (without the PHP7.4 fix that I wrote).

The PHP-FPM postfixadmin pool is not working properly and will prevent the php-fpm.service from starting with the given error log.

A workaround is to :
* Switch to ACL user / group management in the pool (see https://bugs.archlinux.org/task/64683)
* Edit the ACLs of the /run/postfixadmin directory.

/etc/php/php-fpm.d/postfixadmin.conf
[postfixadmin]
user = postfixadmin
group = postfixadmin
listen = /run/postfixadmin/postfixadmin.sock
listen.acl_users = http
listen.acl_groups = http
pm = ondemand
pm.max_children = 4

Append the following line to /usr/lib/tmpfiles.d/postfixadmin.conf :
a+ %t/postfixadmin - - - - group:root:rwx

I don't have the time to check the compatibility of this solution for PHP / PHP-IMAP / PHP-FPM version < 7.4 for now.