exec Module

Table of Contents

1. Admin Guide
1.1. Overview
1.2. Dependencies
1.2.1. OpenSIPS 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(command, [stdin], [stdout], [stderr], [envavp])
1.5. Exported Asyncronous Functions
1.5.1. exec(command, [stdin], [stdout], [stderr], [envavp])
1.6. Known Issues
2. Contributors
2.1. By Commit Statistics
2.2. By Commit Activity
3. Documentation
3.1. Contributors

List of Tables

2.1. Top contributors by DevScore(1), authored commits(2) and lines added/removed(3)
2.2. Most recently active contributors(1) to this module

List of Examples

1.1. Set setvars parameter
1.2. Set time_to_kill parameter
1.3. exec usage
1.4. async exec usage

Chapter 1. Admin Guide

1.1. Overview

The Exec module enables the execution of external commands from the OpenSIPS script. Any valid shell commands are accepted. The final input string is evaluated and executed using the "/bin/sh" symlink/binary. OpenSIPS may additionally pass a lot more information about the request using 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: Any environment variables which are given to the exec module functions must be specified using the '$$' delimiter (e.g., $$SIP_OUSER), otherwise they will be evaluated as OpenSIPS pseudo-variables, throwing scripting errors.

1.2. Dependencies

1.2.1. OpenSIPS Modules

The following modules must be loaded before this module:

  • No dependencies on other OpenSIPS modules.

1.2.2. External Libraries or Applications

The following libraries or applications must be installed before running OpenSIPS with this module loaded:

  • None.

1.3. Exported Parameters

1.3.1. setvars (integer)

Set to 1 to enable setting all above-mentioned environment variables for all executed commands.

WARNING: Before enabling this parameter, make sure your "/bin/sh" is safe from the Shellshock bash vulnerability!!!

Default value is 0 (disabled).

Example 1.1. Set setvars parameter

modparam("exec", "setvars", 1)

1.3.2. time_to_kill (integer)

If set, this parameter specifies the longest time (in seconds) that a program is allowed to execute. Once this duration is exceeded, the program is terminated (SIGTERM).

NOTE: due to internal limitations, a SIGTERM will actually be sent to all job pids once the "time_to_kill" expiration timeout hits. On a standard system, this should have no side-effects, as pids are monotonically increasing in a slow manner, and OpenSIPS should run under the "opensips" user, thus rendering it unable to terminate non-child processes. If this is not the case on your system, do not use the OpenSIPS "time_to_kill" feature -- rather implement it within your external app!

Default value is 0 (disabled).

Example 1.2. Set time_to_kill parameter

modparam("exec", "time_to_kill", 20)

1.4. Exported Functions

1.4.1.  exec(command, [stdin], [stdout], [stderr], [envavp])

Executes an external command. The input is passed to the standard input of the new process, if specified, and the output is saved in the output variable.

The function waits for the external script until it provided all its output (not necessary to actually finish). If no output (standard output or standard error) is required by the function, it will not block at all - it will simply launch the external script and continue the script.

Meaning of the parameters is as follows:

  • command (string) - command to be executed

  • stdin (string, optional) - string to be passed to the standard input of the command

  • stdout (var, optional) - optional output variable which will hold the standard output of the process

  • stderr (var, optional) - optional output variable which will hold the standard error of the process

  • envavp (var, optional) - optional AVP which holds the values for the environment variables to be passed for the command. The names of the environment variables will be "OSIPS_EXEC_#", where "#" starts from 0. For example, if we push two values (e.g. "b" and "a") into an AVP variable, which acts like a stack, OSIPS_EXEC_0 will hold "a", while OSIPS_EXEC_1 will hold "b".

NOTE: If expecting a multi-line formatted output, you should use $avp variables for the "stdout" and "stderr" parameters, to avoid only receiving the last lines of each stream.

WARNING: any OpenSIPS pseudo-vars which may contain special bourne shell (sh/bash) characters should be placed inside quotes, e.g. exec("update-stats.sh '$(ct{re.subst,/'//g})'");

WARNING: "stdin"/"stdout"/"stderr" parameters are not designed for large amounts of data, so one should be careful when using them. Because of the basic implementation, filled up pipes could cause a read deadlock.


Example 1.3. exec usage

$avp(env) = "a";
$avp(env) = "b";
exec("ls -l", , $var(out), $var(err), $avp(env));
xlog("The output is $var(out)\n");
xlog("Received the following error\n$var(err)");
$var(input) = "input";
exec("/home/../myscript.sh", "this is my $var(input) for exec\n", , , $avp(env));

1.5. Exported Asyncronous Functions

1.5.1.  exec(command, [stdin], [stdout], [stderr], [envavp])

Executes an external command. This function does exactly the same as exec() (in terms of input, output and processing), but in an asynchronous way. The script execution is suspended until the external script provided all its output. OpenSIPS waits for the external script to close its output stream, not necessarily to terminate (so the script may still be running when OpenSIPS resumes the script execution on "seeing" EOF on the the output stream)

NOTE: if the stdout variable is missing, OpenSIPS will assume that the output of the external script is not needed and it will NOT WAIT at all for the script. So, if triggered via "launch()", there will be no asynchronous waiting, so no resume route triggering!!

NOTE: this function ignore the "stderr" parameter for now - the asynchronous waiting is done only on the output stream !! This may be fixed in the following versions.

To read and understand more on the asynchronous functions, how to use them and what are their advantages, please refer to the OpenSIPS online Manual.

Example 1.4. async exec usage

async(exec("ruri-changer.sh", $ru, $ru), resume);

route [resume] {

1.6. Known Issues

When imposing an execution timeout using time_to_kill, make sure your "/bin/sh" is a shell which does not fork when executed, case in which the job itself will not be killed, but rather its parent shell, while the job is silently inherited by "init" and will continue to run. "/bin/dash" is one of these troublesome shell environments.

Chapter 2. Contributors

2.1. By Commit Statistics

Table 2.1. Top contributors by DevScore(1), authored commits(2) and lines added/removed(3)

 NameDevScoreCommitsLines ++Lines --
1. Bogdan-Andrei Iancu (@bogdan-iancu)4429651534
2. Liviu Chircu (@liviuchircu)3922344825
3. Jiri Kuthan (@jiriatipteldotorg)27111579152
4. Daniel-Constantin Mierla (@miconda)2619440131
5. Razvan Crainea (@razvancrainea)201632059
6. Jan Janak (@janakj)1610463111
7. Ionut Ionita (@ionutrazvanionita)147612117
8. Andrei Pelinescu-Onciul11829105
9. Vlad Patrascu (@rvlad-patrascu)8246297
10. Henning Westerholt (@henningw)4288

All remaining contributors: Walter Doekes (@wdoekes), Zero King (@l2dy), Anca Vamanu, Dan Pascu (@danpascu), Elena-Ramona Modroiu, Konstantin Bokarius, Vlad Paiu (@vladpaiu), Andreas Granig, Julián Moreno Patiño, Octavian Cerna, Peter Lemenkov (@lemenkov), Edson Gellert Schubert, Dror Wald.

(1) DevScore = author_commits + author_lines_added / (project_lines_added / project_commits) + author_lines_deleted / (project_lines_deleted / project_commits)

(2) including any documentation-related commits, excluding merge commits. Regarding imported patches/code, we do our best to count the work on behalf of the proper owner, as per the "fix_authors" and "mod_renames" arrays in opensips/doc/build-contrib.sh. If you identify any patches/commits which do not get properly attributed to you, please submit a pull request which extends "fix_authors" and/or "mod_renames".

(3) ignoring whitespace edits, renamed files and auto-generated files

2.2. By Commit Activity

Table 2.2. Most recently active contributors(1) to this module

 NameCommit Activity
1. Liviu Chircu (@liviuchircu)Feb 2014 - Jul 2020
2. Bogdan-Andrei Iancu (@bogdan-iancu)Jul 2004 - Apr 2020
3. Zero King (@l2dy)Mar 2020 - Mar 2020
4. Razvan Crainea (@razvancrainea)Jun 2011 - Jan 2020
5. Vlad Patrascu (@rvlad-patrascu)May 2017 - Apr 2019
6. Peter Lemenkov (@lemenkov)Jun 2018 - Jun 2018
7. Ionut Ionita (@ionutrazvanionita)Oct 2014 - Feb 2017
8. Octavian CernaOct 2016 - Oct 2016
9. Julián Moreno PatiñoFeb 2016 - Feb 2016
10. Walter Doekes (@wdoekes)Mar 2014 - Sep 2015

All remaining contributors: Vlad Paiu (@vladpaiu), Anca Vamanu, Dror Wald, Dan Pascu (@danpascu), Daniel-Constantin Mierla (@miconda), Konstantin Bokarius, Edson Gellert Schubert, Henning Westerholt (@henningw), Elena-Ramona Modroiu, Andreas Granig, Jan Janak (@janakj), Andrei Pelinescu-Onciul, Jiri Kuthan (@jiriatipteldotorg).

(1) including any documentation-related commits, excluding merge commits

Chapter 3. Documentation

3.1. Contributors

Last edited by: Bogdan-Andrei Iancu (@bogdan-iancu), Liviu Chircu (@liviuchircu), Peter Lemenkov (@lemenkov), Walter Doekes (@wdoekes), Ionut Ionita (@ionutrazvanionita), Razvan Crainea (@razvancrainea), Anca Vamanu, Dror Wald, Dan Pascu (@danpascu), Daniel-Constantin Mierla (@miconda), Konstantin Bokarius, Edson Gellert Schubert, Elena-Ramona Modroiu, Jan Janak (@janakj).

Documentation Copyrights:

Copyright © 2003 FhG FOKUS