1. Exec Module

Jiri Kuthan


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).