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-rw-r--r--doc/janitor-projects.txt12
-rw-r--r--include/asterisk/pbx.h14
2 files changed, 26 insertions, 0 deletions
diff --git a/doc/janitor-projects.txt b/doc/janitor-projects.txt
index 9d89ef18c..b111204f0 100644
--- a/doc/janitor-projects.txt
+++ b/doc/janitor-projects.txt
@@ -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)
diff --git a/include/asterisk/pbx.h b/include/asterisk/pbx.h
index 1761a9bd7..56bd83fa5 100644
--- a/include/asterisk/pbx.h
+++ b/include/asterisk/pbx.h
@@ -800,6 +800,20 @@ 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);