EXEC module

Admin Guide

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.

Dependencies

OpenSIPS Modules

The following modules must be loaded before this module:

• No dependencies on other OpenSIPS modules.

External Libraries or Applications

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

• None.

Exported Parameters

setvars (integer)

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

Danger

Before enabling this parameter, make sure your “/bin/sh” is safe from the Shellshock bash vulnerability!

Default value is 0 (disabled).

Set 'setvars' parameter

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

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).

Set 'time_to_kill' parameter

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

Exported Functions

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.

Danger

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})’”);

Danger

“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.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, LOCAL_ROUTE, STARTUP_ROUTE, TIMER_ROUTE, EVENT_ROUTE, ONREPLY_ROUTE.

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));
...

Exported Asynchronous Functions

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

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.

async exec usage

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

route [resume] {
...
}

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.

Contributors

By Commit Statistics

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

#	Name	DevScore	Commits	Lines++	Lines—
1.	Bogdan-Andrei Iancu (@bogdan-iancu)	53	32	1102	650
2.	Liviu Chircu (@liviuchircu)	42	23	413	896
3.	Jiri Kuthan (@jiriatipteldotorg)	28	11	1579	152
4.	Daniel-Constantin Mierla (@miconda)	26	19	445	136
5.	Razvan Crainea (@razvancrainea)	23	18	332	64
6.	Jan Janak (@janakj)	18	10	494	142
7.	Ionut Ionita (@ionutrazvanionita)	16	7	633	138
8.	Andrei Pelinescu-Onciul	11	8	33	109
9.	Stefan Darius (@dariusstefan)	9	4	337	94
10.	Vlad Patrascu (@rvlad-patrascu)	8	2	47	298

All remaining contributors: Walter Doekes (@wdoekes), Henning Westerholt (@henningw), Maksym Sobolyev (@sobomax), Zero King (@l2dy), Anca Vamanu, Dan Pascu (@danpascu), Elena-Ramona Modroiu, Vlad Paiu (@vladpaiu), Konstantin Bokarius, Peter Lemenkov (@lemenkov), Octavian Cerna, Julián Moreno Patiño, Andreas Granig, 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

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

By Commit Activity

#	Name	Commit Activity
1.	Bogdan-Andrei Iancu (@bogdan-iancu)	Jul 2004 - Jul 2026
2.	Stefan Darius (@dariusstefan)	Jun 2026 - Jul 2026
3.	Razvan Crainea (@razvancrainea)	Jun 2011 - Jun 2026
4.	Liviu Chircu (@liviuchircu)	Feb 2014 - May 2024
5.	Maksym Sobolyev (@sobomax)	Feb 2023 - Feb 2023
6.	Zero King (@l2dy)	Mar 2020 - Mar 2020
7.	Vlad Patrascu (@rvlad-patrascu)	May 2017 - Apr 2019
8.	Peter Lemenkov (@lemenkov)	Jun 2018 - Jun 2018
9.	Ionut Ionita (@ionutrazvanionita)	Oct 2014 - Feb 2017
10.	Octavian Cerna	Oct 2016 - Oct 2016

All remaining contributors: Julián Moreno Patiño, Walter Doekes (@wdoekes), 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

Documentation

Contributors

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

License

All documentation files (i.e. .md extension) are licensed under the Creative Common License 4.0