Memory leak reading realtime database variable list.

Calling ast_load_realtime() can leak the last list node if the read list
only contains empty variable value items.

* Fixed list filter loop in ast_load_realtime() to delete the list node
immediately instead of the next time through the loop.  The next time
through the loop may not happen if the node to delete is the last in the
list.

(issue ASTERISK-18277)
(issue ASTERISK-18265)
Patches:
      jira_asterisk_18265_v1.8_config.patch (license #5621) patch uploaded by rmudgett


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@332759 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/config.c

@@ -396,6 +396,14 @@ static void ast_comment_destroy(struct ast_comment **comment)
 	*comment = NULL;
 }
 
+static void ast_variable_destroy(struct ast_variable *doomed)
+{
+	ast_comment_destroy(&doomed->precomments);
+	ast_comment_destroy(&doomed->sameline);
+	ast_comment_destroy(&doomed->trailing);
+	ast_free(doomed);
+}
+
 void ast_variables_destroy(struct ast_variable *v)
 {
 	struct ast_variable *vn;
@@ -403,10 +411,7 @@ void ast_variables_destroy(struct ast_variable *v)
 	while (v) {
 		vn = v;
 		v = v->next;
-		ast_comment_destroy(&vn->precomments);
-		ast_comment_destroy(&vn->sameline);
-		ast_comment_destroy(&vn->trailing);
-		ast_free(vn);
+		ast_variable_destroy(vn);
 	}
 }
 
@@ -2142,32 +2147,37 @@ struct ast_variable *ast_load_realtime_all(const char *family, ...)
 
 struct ast_variable *ast_load_realtime(const char *family, ...)
 {
-	struct ast_variable *res, *cur, *prev = NULL, *freeme = NULL;
+	struct ast_variable *res;
+	struct ast_variable *cur;
+	struct ast_variable **prev;
 	va_list ap;
 
 	va_start(ap, family);
 	res = ast_load_realtime_helper(family, ap);
 	va_end(ap);
 
-	/* Eliminate blank entries */
-	for (cur = res; cur; cur = cur->next) {
-		if (freeme) {
-			ast_free(freeme);
-			freeme = NULL;
-		}
-
+	/* Filter the list. */
+	prev = &res;
+	cur = res;
+	while (cur) {
 		if (ast_strlen_zero(cur->value)) {
-			if (prev)
-				prev->next = cur->next;
-			else
-				res = cur->next;
-			freeme = cur;
-		} else if (cur->value[0] == ' ' && cur->value[1] == '\0') {
-			char *vptr = (char *) cur->value;
-			vptr[0] = '\0';
-			prev = cur;
+			/* Eliminate empty entries */
+			struct ast_variable *next;
+
+			next = cur->next;
+			*prev = next;
+			ast_variable_destroy(cur);
+			cur = next;
 		} else {
-			prev = cur;
+			/* Make blank entries empty and keep them. */
+			if (cur->value[0] == ' ' && cur->value[1] == '\0') {
+				char *vptr = (char *) cur->value;
+
+				vptr[0] = '\0';
+			}
+
+			prev = &cur->next;
+			cur = cur->next;
 		}
 	}
 	return res;