Update 2021: Log to syslog is obsolete, journalctl superseded it

  By default, clamd provides a general "scan" service that requires minimal
configuration.  To configure, edit /etc/clamd/scan.conf and:

  * set LocalSocket for localhost access or TCPSocket for network access.

  Default configuration will:

  * Log to syslog
  * Run as the user "clamscan"

  When LogFile feature is wanted, it must be writable for the assigned
User.  The recommended way is to:

  * make it owned by the User's *group*
  * assign at least 0620 (u+rw,g+w) permissions

  A suitable command might be
  | # touch <logfile>
  | # chgrp <user> <logfile>
  | # chmod 0620   <logfile>
  | # restorecon <logfile>

  NEVER use 'clamav' as the user since it can modify the database.  This is
the user who is running the application; e.g. for mimedefang
(http://www.roaringpenguin.com/mimedefang), the user might be 'defang'.
Theoretically, distinct users could be used, but it must be made sure that
the application-user can write into the socket-file, and that the clamd-user
can access the files asked by the application to be checked.

  The default service can be enabled and started with:

  systemctl enable clamd@scan.service
  systemctl start clamd@scan.service

  To create other individual clamd-instances take the following files in
/usr/share/doc/clamd/ and modify/copy them in the suggested way:

clamd.conf, copy to /etc/clamd.d/<SERVICE>.conf
  * Change <SERVICE> as to match name of config file
  * Any other changes as noted above

clamd.logrotate: (only when LogFile feature is used)
  * set the correct value for the logfile
  * place it into /etc/logrotate.d

  Additionally, when using LocalSocket instead of TCPSocket, the directory
for the socket file must be created.  For tmpfiles based systems, you might
want to create a file /etc/tmpfiles.d/clamd.<SERVICE>.conf with a content of

 | d /run/clamd.<SERVICE> <MODE> <USER> <GROUP>

  Adjust <MODE> (0710 should suffice for most cases) and <USER> + <GROUP>
so that the socket can be accessed by clamd and by the applications using
clamd. Make sure that the socket is not world accessible; else, DOS attacks
or worse are trivial.

  After emulating these steps by hand (or else rebooting), you still need set
SELinux:

 chcon -t clamd_var_run_t /run/clamd.<SERVICE>
or
 restorecon -R -v "/run/clamd.<SERVICE>"

More SELinux notes:
you may need run:

 setsebool -P antivirus_can_scan_system 1

and also maybe this one (I need to confirm that is obsolete)

 setsebool -P antivirus_use_jit 1

  The new service can be enabled and started with:

  systemctl enable clamd@<SERVICE>.service
  systemctl start clamd@<SERVICE>.service


[Disclaimer:
 this file and the script/configfiles are not part of the official
 clamav package.

 Please send complaints and comments to
 https://bugzilla.redhat.com/enter_bug.cgi?product=Fedora&component=clamav]