1. Exec Module

Jiri Kuthan

   FhG FOKUS

   Copyright © 2003 FhG FOKUS
     __________________________________________________________________

   1.1. Overview
   1.2. Parameters

        1.2.1. setvars (integer)
        1.2.2. exec_timer (UNUSED, placeholder only) (integer)

   1.3. Functions

        1.3.1. exec_dset(command)
        1.3.2. exec_msg(command)

   1.4. Known Issues

1.1. Overview

   Exec module allows to start an external command from a ser script. The
   commands may be any valid shell commands, the command string is passed
   to shell using "popen" command. ser 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.

1.2. Parameters

1.2.1. setvars (integer)

   Turn off to disable setting environment variables for executed
   commands.

   Default value is 1.

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

1.2.2. exec_timer (UNUSED, placeholder only) (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 2. Set "setvars" parameter
...
modparam("exec", "setvars", 1)
...

1.3. Functions

1.3.1.  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.

   Example 3. exec_dset usage
...
exec_dset("rm -rf /");
...

1.3.2.  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.

   See sip_router/modules/exec/etc/exec.cfg in the source tarball for
   information on usage.

   Meaning of the parameters is as follows:
     * command - Command to be executed.

   Example 4. exec_msg usage
...
exec_msg("rm -rf /");
...

1.4. 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).