Fix some potential misuses of ast_str in the code.

Passing an ast_str pointer by value that then calls
ast_str_set(), ast_str_set_va(), ast_str_append(), or
ast_str_append_va() can result in the pointer originally
passed by value being invalidated if the ast_str had
to be reallocated.

This fixes places in the code that do this. Only the
example in ccss.c could result in pointer invalidation
though since the other cases use a stack-allocated ast_str
and cannot be reallocated.

I've also updated the doxygen in strings.h to include
notes about potential misuse of the functions mentioned
previously.

Review: https://reviewboard.asterisk.org/r/2161
........

Merged revisions 375025 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 375026 from http://svn.asterisk.org/svn/asterisk/branches/10
........

Merged revisions 375027 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@375044 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 9 insertions, 9 deletions

diff --git a/main/ccss.c b/main/ccss.c
index 5dd1d70bf..70e16c7a9 100644
--- a/main/ccss.c
+++ b/main/ccss.c
@@ -3446,7 +3446,7 @@ struct ast_cc_monitor *ast_cc_get_monitor_by_recall_core_id(const int core_id, c
  * \param dialstring A new dialstring to add
  * \retval void
  */
-static void cc_unique_append(struct ast_str *str, const char *dialstring)
+static void cc_unique_append(struct ast_str **str, const char *dialstring)
 {
 	char dialstring_search[AST_CHANNEL_NAME];
 
@@ -3455,10 +3455,10 @@ static void cc_unique_append(struct ast_str *str, const char *dialstring)
 		return;
 	}
 	snprintf(dialstring_search, sizeof(dialstring_search), "%s%c", dialstring, '&');
-	if (strstr(ast_str_buffer(str), dialstring_search)) {
+	if (strstr(ast_str_buffer(*str), dialstring_search)) {
 		return;
 	}
-	ast_str_append(&str, 0, "%s", dialstring_search);
+	ast_str_append(str, 0, "%s", dialstring_search);
 }
 
 /*!
@@ -3476,7 +3476,7 @@ static void cc_unique_append(struct ast_str *str, const char *dialstring)
  * \param str Where we will store CC_INTERFACES
  * \retval void
  */
-static void build_cc_interfaces_chanvar(struct ast_cc_monitor *starting_point, struct ast_str *str)
+static void build_cc_interfaces_chanvar(struct ast_cc_monitor *starting_point, struct ast_str **str)
 {
 	struct extension_monitor_pvt *extension_pvt;
 	struct extension_child_dialstring *child_dialstring;
@@ -3485,7 +3485,7 @@ static void build_cc_interfaces_chanvar(struct ast_cc_monitor *starting_point, s
 	size_t length;
 
 	/* Init to an empty string. */
-	ast_str_truncate(str, 0);
+	ast_str_truncate(*str, 0);
 
 	/* First we need to take all of the is_valid child_dialstrings from
 	 * the extension monitor we found and add them to the CC_INTERFACES
@@ -3508,9 +3508,9 @@ static void build_cc_interfaces_chanvar(struct ast_cc_monitor *starting_point, s
 	/* str will have an extra '&' tacked onto the end of it, so we need
 	 * to get rid of that.
 	 */
-	length = ast_str_strlen(str);
+	length = ast_str_strlen(*str);
 	if (length) {
-		ast_str_truncate(str, length - 1);
+		ast_str_truncate(*str, length - 1);
 	}
 	if (length <= 1) {
 		/* Nothing to recall?  This should not happen. */
@@ -3545,7 +3545,7 @@ int ast_cc_agent_set_interfaces_chanvar(struct ast_channel *chan)
 
 	AST_LIST_LOCK(interface_tree);
 	monitor = AST_LIST_FIRST(interface_tree);
-	build_cc_interfaces_chanvar(monitor, str);
+	build_cc_interfaces_chanvar(monitor, &str);
 	AST_LIST_UNLOCK(interface_tree);
 
 	pbx_builtin_setvar_helper(chan, "CC_INTERFACES", ast_str_buffer(str));
@@ -3597,7 +3597,7 @@ int ast_set_cc_interfaces_chanvar(struct ast_channel *chan, const char * const e
 		return -1;
 	}
 
-	build_cc_interfaces_chanvar(monitor_iter, str);
+	build_cc_interfaces_chanvar(monitor_iter, &str);
 	AST_LIST_UNLOCK(interface_tree);
 
 	pbx_builtin_setvar_helper(chan, "CC_INTERFACES", ast_str_buffer(str));