AVFILTER_SIG(8)

avfilter_sig - signal avfilter to reload  

avfilter_sig [-l] [-t timeout] [-p pid] ["reload" ["config" | "virus"]]

avfilter_sig --help | --version  

In the first form, avfilter_sig sends a signal to avfilter so that the latter reloads its configuration file, the virus data base, or both. The configuration file name cannot be changed this way.

Option -t allow to specify a timeout, in seconds. The default is 90.

The process id of avfilter can be overridden with -p, which also changes the pipe name to the current directory; if not using -p, the id is read from avfilter pid file.

A named pipe is used to read the response. Existence of the pipe is tested to avoid concurrent requests. When the -p option is used avfilter_sig uses ``./avfilter_sig.pipe'' as the pipe name.

The output from avfilter, read through the pipe, is displayed on stdout unless the -l option is given. In the latter case it is sent to syslog.

The signal sent is:

HUP

If neither "config" nor "virus" is specified.

USR1

For "config", to reload configuration.

USR2

For "virus", to reload the virus data base.

 

Exit status is 0 if ok, 1 for daemon error, higher for other errors including daemon not running, pipe already in use, etc.  

Users of freshclam can set:

        OnUpdateExecute avfilter_sig -l reload virus 

Other (unofficial) scripts have similar reload_opt, which can be set likewise.

If avfilter_sig is not in $PATH (it is installed in ${exec_prefix}/sbin), specify its full path; (freshclam issues a system(3) call to execute it).

Mind permissions; avfilter and freshclam likely run with as different users. Setting avfilter_sig setuid ("chmod u+s") is the easiest solution. You can also "./configure --with-setuid-sig" to get that. The requirements are that avfilter_sig can read avfilter.pid and send signals to avfilter, and that avfilter can write to the pipe created by avfilter_sig.  

PIPE PERMISSIONS

avfilter_sig creates a user-writable pipe. If it detects its effective UID is not Courier's, it makes the pipe group-writable. In that case, it will also attempt to change the pipe ownership to Courier's. Thus, an adequate assignment of group memberships may work.  

/local/courier/var/path/tmp/avfilter.pid

/local/courier/var/path/tmp/avfilter_sig.pipe

./avfilter_sig.pipe (when using -p)  

Alessandro Vesely <vesely@tana.it>  

freshclam.conf(5), avfilter(8)