Merged revisions 111908-111909 via svnmerge from

https://origsvn.digium.com/svn/asterisk/trunk

........
r111908 | russell | 2008-03-28 17:45:43 -0500 (Fri, 28 Mar 2008) | 3 lines

Note a minor race condition that I noticed while reviewing Jeff's changes
to this code.

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r111909 | russell | 2008-03-28 17:50:46 -0500 (Fri, 28 Mar 2008) | 3 lines

Make some notes about common usage of pbx_builtin_getvar_helper() that is not
thread-safe.

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git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.0@111910 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Russell Bryant
2008-03-28 22:52:02 +00:00
parent 557219e0dc
commit 1769846227
3 changed files with 31 additions and 0 deletions

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@@ -1,3 +1,15 @@
-- There a bunch of places where the result of pbx_builtin_getvar_helper()
gets stored and used. This is not threadsafe. This code should be replaced
with the following thread-safe version:
const char *var;
ast_channel_lock(chan);
if ((var = pbx_builtin_getvar_helper(chan, "MYVAR"))) {
var = ast_strdupa(var);
}
ast_channel_unlock(chan);
-- Convert all existing uses of astobj.h to astobj2.h
-- (chan_sip already in progress in a branch)

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@@ -806,6 +806,20 @@ int pbx_builtin_serialize_variables(struct ast_channel *chan, struct ast_str **b
/*!
* \note Will lock the channel.
*
* \note This function will return a pointer to the buffer inside the channel
* variable. This value should only be accessed with the channel locked. If
* the value needs to be kept around, it should be done by using the following
* thread-safe code:
* \code
* const char *var;
*
* ast_channel_lock(chan);
* if ((var = pbx_builtin_getvar_helper(chan, "MYVAR"))) {
* var = ast_strdupa(var);
* }
* ast_channel_unlock(chan);
* \endcode
*/
const char *pbx_builtin_getvar_helper(struct ast_channel *chan, const char *name);

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@@ -21,6 +21,11 @@
* \brief Background DNS update manager
*
* \author Kevin P. Fleming <kpfleming@digium.com>
*
* \bug There is a minor race condition. In the event that an IP address
* of a dnsmgr managed host changes, there is the potential for the consumer
* of that address to access the in_addr data at the same time that the dnsmgr
* thread is in the middle of updating it to the new address.
*/
#include "asterisk.h"