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<!-- Module User's Guide -->

<chapter>
	
	<title>&adminguide;</title>
	
	<section id="exec.overview">
	<title>Overview</title>
	<para>
		The exec module allows external commands to be executed from a &kamailio; 
		script. The commands may be any valid shell commands--the command string is 
		passed to the shell using <quote>popen</quote> command. &kamailio; passes 
		additional information about the request in environment variables:
	</para>
	<itemizedlist>
		<listitem>
		<para>
			SIP_HF_&lt;hf_name&gt; contains value of each header field in 
			request. If a header field occurred multiple times, values are 
			concatenated and comma-separated. &lt;hf_name&gt; is in capital 
			letters. Ff a header-field name occurred in compact form, 
			&lt;hf_name&gt; is canonical.
		</para>
		</listitem>
		<listitem>
		<para>
			SIP_TID is transaction identifier. All request retransmissions or 
			CANCELs/ACKs associated with a previous INVITE result in the same 
			value.
		</para>
		</listitem>
		<listitem>
		<para>
			SIP_DID is dialog identifier, which is the same as to-tag. 
			Initially, it is empty.
		</para>
		</listitem>
		<listitem>
		<para>
			SIP_SRCIP is source &ip; address from which request came.
		</para>
		</listitem>
		<listitem>
		<para>
			SIP_ORURI is the original request &uri;.
		</para>
		</listitem>
		<listitem>
		<para>
			SIP_RURI is <emphasis>current</emphasis> request &uri; (if 
			unchanged, equal to original).
		</para>
		</listitem>
		<listitem>
		<para>
			SIP_USER is userpart of <emphasis>current</emphasis> request &uri;.
		</para>
		</listitem>
		<listitem>
		<para>
			SIP_OUSER is userpart of original request &uri;.
		</para>
		</listitem>
	</itemizedlist>
	<para>
		NOTE: The environment variables must be specified with double $
		(e.g., $$SIP_OUSER) in the parameters given to exec functions.
		Otherwise they will be evaluated as &kamailio; pseudo-variables,
		throwing errors.
	</para>
	</section>

	<section>
	<title>Dependencies</title>
	<section>
		<title>&kamailio; Modules</title>
		<para>
		The following modules must be loaded before this module:
			<itemizedlist>
			<listitem>
			<para>
				<emphasis>No dependencies on other &kamailio; modules</emphasis>.
			</para>
			</listitem>
			</itemizedlist>
		</para>
	</section>
	<section>
		<title>External Libraries or Applications</title>
		<para>
		The following libraries or applications must be installed before running
		&kamailio; with this module loaded:
			<itemizedlist>
			<listitem>
			<para>
				<emphasis>None</emphasis>.
			</para>
			</listitem>
			</itemizedlist>
		</para>
	</section>
	</section>

	<section>
	<title>Parameters</title>
	<section id="exec.p.setvars">
		<title><varname>setvars</varname> (integer)</title>
		<para>
		Turn off to disable setting environment variables for executed commands.
		</para>
		<para>
		<emphasis>
			Default value is 1.
		</emphasis>
		</para>
		<example>
		<title>Set <quote>setvars</quote> parameter</title>
		<programlisting format="linespecific">
...
modparam("exec", "setvars", 1)
...
</programlisting>
		</example>
	</section>
	<section id="exec.p.time_to_kill">
		<title>
			<varname>time_to_kill</varname> (integer)
		</title>
		<para>
		Specifies the longest time a program is allowed to execute. If the 
		time is exceeded, the program is killed.
		</para>
		<para>
		<emphasis>
			Default value is 0.
		</emphasis>
		</para>
		<example>
		<title>Set <quote>time_to_kill</quote> parameter</title>
		<programlisting format="linespecific">
...
modparam("exec", "time_to_kill", 20)
...
</programlisting>
		</example>
	</section>
	</section>
	<section>
	<title>Functions</title>
	<section id="exec.f.exec_dset">
		<title>
		<function moreinfo="none">exec_dset(command)</function>
		</title>
		<para>
		Executes an external command. Current &uri; is passed to the command 
		as parameter. Output of the command is considered &uri; set 
		(separated by lines).
		</para>
		<para>Meaning of the parameters is as follows:</para>
		<itemizedlist>
		<listitem>
			<para><emphasis>command</emphasis> - Command to be executed. It can
			include pseudo- variabes;
			</para>
		</listitem>
		</itemizedlist>
		<para>
		WARNING: if the var you are passing out has a bash special
		character in it, the var needs to be placed inside quotes, for example:
		exec_dset("print-contact.sh '$ct'");
		</para>
		<para>
		This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
		</para>
		<example>
		<title><function moreinfo="none">exec_dset</function> usage</title>
		<programlisting format="linespecific">
...
exec_dset("echo TEST > /tmp/test.txt");
exec_dset("echo TEST > /tmp/$rU.txt");
...
</programlisting>
		</example>
	</section>
	<section id="exec.f.exec_msg">
		<title>
		<function moreinfo="none">exec_msg(command)</function>
		</title>
		<para>
		Executes an external command. The whole message is passed to it in 
		input, no command-line parameters are added, output of the command is 
		not processed.
		</para>
		<para>
		The <quote>examples</quote> directory in the source tarball contains several examples
		that shows how to use this function.
		</para>
		<para>Meaning of the parameters is as follows:</para>
		<itemizedlist>
		<listitem>
			<para><emphasis>command</emphasis> - Command to be executed. It
			can include pseudo-variables.
			</para>
		</listitem>
		</itemizedlist>
		<para>
		WARNING: if the var you are passing out has a bash special
		character in it, the var needs to be placed inside quotes, for example:
		exec_msg("print-contact.sh '$ct'");
		</para>
		<para>
		This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
		</para>
		<example>
		<title><function moreinfo="none">exec_msg</function> usage</title>
		<programlisting format="linespecific">
...
exec_msg("echo TEST > /tmp/test.txt");
exec_msg("echo TEST > /tmp/$rU.txt");
...
</programlisting>
		</example>
	</section>
	<section id="exec.f.exec_avp">
		<title>
		<function moreinfo="none">exec_avp(command [, avplist])</function>
		</title>
		<para>
		Executes an external command. Each line from output of the command
		is saved in an AVP from 'avplist'. If 'avplist' is missing, the
		AVPs are named 1, 2, 3, ...
		</para>
		<para>Meaning of the parameters is as follows:</para>
		<itemizedlist>
		<listitem>
			<para><emphasis>command</emphasis> - Command to be executed. It can
			include pseudo- variabes;
			</para>
		</listitem>
		<listitem>
			<para><emphasis>avplist</emphasis> - comma separated list with AVP 
			names to store the result in;
			</para>
		</listitem>
		</itemizedlist>
		<para>
		WARNING: if the var you are passing out has a bash special
		character in it, the var needs to be placed inside quotes, for example:
		exec_avp("print-contact.sh '$ct'");
		</para>
		<para>
		This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
		</para>
		<example>
		<title><function moreinfo="none">exec_avp</function> usage</title>
		<programlisting format="linespecific">
...
exec_avp("echo TEST");
exec_avp("echo TEST", "$avp(s:test)");
...
</programlisting>
		</example>
	</section>
	<section id="exec.f.exec_cmd">
		<title>
		<function moreinfo="none">exec_cmd(command)</function>
		</title>
		<para>
			Executes an external command. It is a lightweight version, which
			does not pass the SIP message as parameter, does not set the
			environment variables and it does not use the output of the command.
		</para>
		<para>Meaning of the parameters is as follows:</para>
		<itemizedlist>
		<listitem>
			<para><emphasis>command</emphasis> - Command to be executed. It
			can include pseudo-variables.
			</para>
		</listitem>
		</itemizedlist>
		<para>
		WARNING: if the var you are passing out has a bash special
		character in it, the var needs to be placed inside quotes, for example:
		exec_msg("print-contact.sh '$ct'");
		</para>
		<para>
		This function can be used from ANY_ROUTE.
		</para>
		<example>
		<title><function moreinfo="none">exec_cmd</function> usage</title>
		<programlisting format="linespecific">
...
exec_cmd("echo TEST > /tmp/test.txt");
exec_cmd("echo TEST > /tmp/$rU.txt");
...
</programlisting>
		</example>
	</section>
	</section>
	<section id="exec.known_issues">
	<title>Known Issues</title>
	<para>
		There is currently no guarantee that scripts ever return and stop
		blocking the &sip; server. (There is kill.c but it is not used along with
		the current mechanisms based on popen. Besides that kill.c is ugly).
	</para>
	</section>
</chapter>

