Asterisk 13 - system() dialplan app cannot call bash script on filing system

Question

This was working fine in Asterisk 1.8.32.3 - I'm testing with Asterisk 13.22.0 on Centos 7 running as root (already - as you'll see below):

same=>n,System(/usr/src/bash/setData.sh ${CHANNEL(accountcode)})

The script's permissions:

[root@localhost bash]# ls -l
-rwxr-xr-x 1 root root 1493 Jan 20  2016 setData.sh 
[root@localhost bash]# pwd 
/usr/src/bash
[root@localhost bash]#

I've upgraded to Asterisk 13, and Asterisk is now incapable of executing the setData.sh script:

[Jul 25 10:33:21] WARNING[30982][C-00000238] app_system.c: Unable to execute '/usr/src/bash/setData.sh'

I've looked at numerous posts about this, but none are applicable or end blind with no solution.

I've tried running asterisk as root, no luck - see above.

I've set permissions on the script to executable by everybody, not working.

I've changed the dialplan code to

same=>n,System(/bin/bash /usr/src/bash/setData.sh ${CHANNEL(accountcode)})

also no effect.

I've also tried completely disabling / deactivating SELinux in Centos 7 - no effect, error persists.

If you run the script from the shell / xterm, it works correctly.

How does one get Asterisk 13 to execute a simple BASH script via the System() dialplan application as worked in previous Asterisk versions such as 1.6 and 1.8?

Thanks!

Stefan

I suggest you run this under strace so that you can see the exact underlying OS error message. — cdarke

Stefan Stefan · Accepted Answer · 2018-07-27T14:55:23

Ok this is resolved.

Turns out that the problem is that one of the parameters I tried to pass through the SYSTEM() and SHELL() calls in my dialplan, contained a linefeed character (\n, or hex 0x0a).

It appears that in Asterisk 13.22.0, in a call to SYSTEM() or SHELL(), parsing and evaluation of Asterisk channel variables passed into SYSTEM() or SHELL() STOPS when a linefeed (\n) character is hit.

Once I cleaned up the variables (removing the \n one variable contained, originated from a UUID I was generating) and all variables' contents passed to the SYSTEM() dialplan application were "clean" - without any \n characters - the SYSTEM() dialplan application started functioning normally and started calling my BASH script with paramters with Asterisk channel variable values, as intended.

No changes to my dialplan, but in a bash script I was running to get the UUID (via a CURL to a Java application) I had this:

echo $uuid

and all I had to do was this:

echo -n $uuid

The moment that was done and the UUID without the trailing linefeed was fed to SYSTEM() in my dialplan on Asterisk 13.22.0, SYSTEM() started working and everything was functional.

Asterisk 13 - system() dialplan app cannot call bash script on filing system

2 Answers