[asterisk-bugs] [Asterisk 0016947]: app_fax exits with returncode -1, transmission error, although fax is sent correctly, AGI aborts execution

[Asterisk Bug Tracker]

The following issue has been UPDATED. 
====================================================================== 
https://issues.asterisk.org/view.php?id=16947 
====================================================================== 
Reported By:                ChrisDE
Assigned To:                
====================================================================== 
Project:                    Asterisk
Issue ID:                   16947
Category:                   Applications/app_fax
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     feedback
Asterisk Version:           SVN 
JIRA:                       SWP-982 
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
====================================================================== 
Date Submitted:             2010-03-02 15:12 CST
Last Modified:              2010-03-03 13:40 CST
====================================================================== 
Summary:                    app_fax exits with returncode -1, transmission
error, although fax is sent correctly, AGI aborts execution
Description: 
After several tests I figured out a problem with app_fax and probably
another problem with AGI.

First, as can be seen in the logs, app_fax always terminates with

app_fax.c:764 transmit: Transmission error

Although the fax always goes through and is received correctly by the
remote fax. As can be seen in the logs the remote side sends a sip 'BYE'
message (probably because the fax has gone through?). Probably this is not
correclty handled by app_fax and causes the transmission error?

This is the first part of the problem. The second part is that app_fax
then returns '-1'. This causes the AGI script to be aborted. This is very
bad behavior since then it is not possible to handle further processing
(read variables set by app_fax like 'FAXSTATUS', 'FAXPAGES', etc.).

In some cases of my trials (also with old phpagi 1.6 instead of 2.14) the
AGI script had not been terminated immediately but continued making the
next steps (read variables). There I saw that return value of app_fax was
also FAXSTATUS=SUCCESS.

So I think this time there is really something wrong with app_fax.c and
not in spandsp. And also the way res_agi.c handles returnvalues in case of
'EXEC' could be wrong OR app_fax should never return '-1' to cause the agi
script to be aborted.
====================================================================== 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2010-03-03 13:40 lmadsen        Asterisk Version         1.6.0.24 => SVN     
2010-03-03 13:40 lmadsen        Description Updated                          
======================================================================