[asterisk-bugs] [Asterisk 0017450]: [patch] "setvar" can add multiple variables with the same name to a channel

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
====================================================================== 
https://issues.asterisk.org/view.php?id=17450 
====================================================================== 
Reported By:                nahuelgreco
Assigned To:                jrose
====================================================================== 
Project:                    Asterisk
Issue ID:                   17450
Category:                   Channels/chan_dahdi
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     closed
Asterisk Version:           SVN 
JIRA:                       SWP-1635 
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases):  trunk 
SVN Revision (number only!): 267095 
Request Review:              
Resolution:                 fixed
Fixed in Version:           
====================================================================== 
Date Submitted:             2010-06-02 17:28 CDT
Last Modified:              2011-04-12 15:35 CDT
====================================================================== 
Summary:                    [patch] "setvar" can add multiple variables with the
same name to a channel
Description: 
Suppose the following piece of chan_dahdi.conf:

  setvar=V1=foo
  channel => 1

  setvar=V2=bar
  channel => 2

  setvar=V1=baz
  channel => 3

In the current trunk version, each channel (dahdi_pvt structure) will have
his own copies of the variables (after
https://issues.asterisk.org/view.php?id=16359 fix). For example, the
ast_variables linked list for channel 3 will have the following form:

  channel 3:   V1=foo -> V2=bar -> V1=baz

When a call is made and dahdi_new(...) is executed, dahdi_new(...) will
processes the variables list left-to-right, so for a call in channel 3 the
value of V1 for that call will be finally "baz" because is the last one to
be set by dahdi_new(...). This makes the bug benevolous, the call variables
will be ok, but if you do a "dahdi show channel 3" you will see the two
versions of V1, and that's wrong. Before the
https://issues.asterisk.org/view.php?id=16359 fix the bug was worse,
because the call in channel 3 got V1=foo.

A patch against trunk removing the duplicates is attached.

Also, there is a conceptual mismatch. The documentation in
chan_dahdi.conf.sample states that "setvar" defines a "Channel variable to
be set for all calls from this channel". Maybe the correct behaviour is to
get only V1 defined for channel 3 and not V2, by resetting the setvar list
(confp->chan.vars) after each "channel" statement. 

I also think the linked list built at confp->chan.vars is probably leaking
across reloads.

====================================================================== 

---------------------------------------------------------------------- 
 (0133683) svnbot (reporter) - 2011-04-12 15:35
 https://issues.asterisk.org/view.php?id=17450#c133683 
---------------------------------------------------------------------- 
Repository: asterisk
Revision: 313435

U   branches/1.6.2/channels/chan_dahdi.c

------------------------------------------------------------------------
r313435 | jrose | 2011-04-12 13:44:44 -0500 (Tue, 12 Apr 2011) | 30 lines

fixing stupid mistake with putting code before variable declaration
........

  Merged revisions 313433 via svnmerge from 
  https://origsvn.digium.com/svn/asterisk/branches/1.6.2

  ........

    r313432 | jrose | 2011-04-12 13:12:29 -0500 (Tue, 12 Apr 2011) | 14
lines
    
	reload Chan_dahdi memory leak caused by variables

	chan_dahdi reloading with variables set via setvar in chan_dahdi.conf
would
	stay in the dahdi_pvt structs for individual channels (causing them to
just
	continue adding the new ones to the list) and also there was a memory
leak
	causes by the conf objects. This patch resolves both of these by using 
	ast_variables_destroy during the loading process.

	(closes issue https://issues.asterisk.org/view.php?id=17450)
	Reported by: nahuelgreco
	Patches:
		patch.diff uploaded by jrose (license 1225)
		Tested by: tilghman, jrose
	Review: https://reviewboard.asterisk.org/r/1170/

  ........

........


------------------------------------------------------------------------

http://svn.digium.com/view/asterisk?view=rev&revision=313435 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2011-04-12 15:35 svnbot         Checkin                                      
2011-04-12 15:35 svnbot         Note Added: 0133683                          
======================================================================