exec Module

Jiri Kuthan

   FhG FOKUS

Daniel-Constantin Mierla

   <miconda@gmail.com>

Edited by

Jan Janak

   Copyright © 2003 FhG FOKUS
   Revision History
   Revision $Revision: 5141 $ $Date: 2008-08-06 12:08:33 +0200
                              (Mi, 06 Aug 2008) $
     __________________________________________________________

   Table of Contents

   1. Admin Guide

        1.1. Overview
        1.2. Dependencies

              1.2.1. Kamailio Modules
              1.2.2. External Libraries or Applications

        1.3. Exported Parameters

              1.3.1. setvars (integer)
              1.3.2. time_to_kill (integer)

        1.4. Exported Functions

              1.4.1. exec_dset(command)
              1.4.2. exec_msg(command)
              1.4.3. exec_avp(command [, avplist])

        1.5. Known Issues

   List of Examples

   1.1. Set "setvars" parameter
   1.2. Set "time_to_kill" parameter
   1.3. exec_dset usage
   1.4. exec_msg usage
   1.5. exec_avp usage

Chapter 1. Admin Guide

1.1. Overview

   Exec module allows to start an external command from a Kamailio
   script. The commands may be any valid shell commands--the
   command string is passed to shell using "popen" command.
   Kamailio passes additionally lot of information about request
   in environment variables:
     * SIP_HF_<hf_name> contains value of each header field in
       request. If a header field occurred multiple times, values
       are concatenated and comma-separated. <hf_name> is in
       capital letters. Ff a header-field name occurred in compact
       form, <hf_name> is canonical.
     * SIP_TID is transaction identifier. All request
       retransmissions or CANCELs/ACKs associated with a previous
       INVITE result in the same value.
     * SIP_DID is dialog identifier, which is the same as to-tag.
       Initially, it is empty.
     * SIP_SRCIP is source IP address from which request came.
     * SIP_ORURI is original request URI.
     * SIP_RURI is current request URI (if unchanged, equal to
       original).
     * SIP_USER is userpart of current request URI.
     * SIP_OUSER is userpart of original request URI.

   NOTE: The envirnment 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.

1.2. Dependencies

1.2.1. Kamailio Modules

   The following modules must be loaded before this module:
     * No dependencies on other Kamailio modules.

1.2.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running Kamailio with this module loaded:
     * None.

1.3. Exported Parameters

1.3.1. setvars (integer)

   Turn off to disable setting environment variables for executed
   commands.

   Default value is 1.

   Example 1.1. Set "setvars" parameter
...
modparam("exec", "setvars", 1)
...

1.3.2.  time_to_kill (integer)

   Specifies the longest time a program is allowed to execute. If
   the time is exceeded, the program is killed.

   Default value is 0.

   Example 1.2. Set "time_to_kill" parameter
...
modparam("exec", "time_to_kill", 20)
...

1.4. Exported Functions

1.4.1.  exec_dset(command)

   Executes an external command. Current URI is passed to the
   command as parameter. Output of the command is considered URI
   set (separated by lines).

   Meaning of the parameters is as follows:
     * command - Command to be executed. It can include pseudo-
       variabes;

   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'");

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

   Example 1.3. exec_dset usage
...
exec_dset("echo TEST > /tmp/test.txt");
exec_dset("echo TEST > /tmp/$rU.txt");
...

1.4.2.  exec_msg(command)

   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.

   The "examples" directory in the source tarball contains several
   examples that shows how to use this function.

   Meaning of the parameters is as follows:
     * command - Command to be executed. It can include
       pseudo-variables.

   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'");

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

   Example 1.4. exec_msg usage
...
exec_msg("echo TEST > /tmp/test.txt");
exec_msg("echo TEST > /tmp/$rU.txt");
...

1.4.3.  exec_avp(command [, avplist])

   Executes an external command. Each line from output of the
   command is saved in an AVP from 'avplist'. If 'avplist' is
   missing, the AVP are named 1, 2, 3, ...

   Meaning of the parameters is as follows:
     * command - Command to be executed. It can include pseudo-
       variabes;
     * avplist - comma separated list with AVP names to store the
       result in;

   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'");

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

   Example 1.5. exec_avp usage
...
exec_avp("echo TEST");
exec_avp("echo TEST", "$avp(s:test)");
...

1.5. Known Issues

   There is currently no guarantee that scripts ever return and
   stop blocking 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).
