[Asterisk-Dev] Interrupted playback of messages (ast_waitstream)

[Lars Sundqvist]

Spent the day tracking down a problem with randomly interrupted messages 
(playback/background) and thought i would share my results if someone 
else has similar problems.

file.c:ast_waitstream streams a file until a dtmf tone that matches a 
character in char* parameter breakon is received.
To determine if the DTMF tone matches breakon, strchr is used and thats 
where the problem lies, strchr matches any character in the string 
INCLUDING the \0 char.

In the system i was debugging there is some random noise coming in from 
PSTN which is detected as DTMF characters with value 0 (0, not '0') and 
with the current code in ast_waitstream that breaks the playback and 
asterisk instead waits for further dtmf input.

Fixed it by ignoring any dtmf with value 0.

Seems like a bug in ast_waitstream to me, but then this is the first 
time i had a look at the asterisk code...maybe the bug lies elsewhere 
and the dtmf with value 0 never should reach that far.

/Lasse

Lars Sundqvist
Algitech Consulting AB