From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Mon, 18 Nov 2019 19:43:06 +0000 (-0500)
Subject: Fix: invalid use of destructor in dynamic pointer array
X-Git-Tag: v2.11.1~40
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=b7912f944d7f9548ea811fd81c7df321b829efd5;p=lttng-tools.git

Fix: invalid use of destructor in dynamic pointer array

A dynamic pointer array is built on top of a dynamic array and uses
the dynamic array's internal "destructor" field to store the
user-specified destructor.

lttng_dynamic_pointer_array_remove_pointer currently uses
the dynamic array's remove_element directly which causes the
user destructor to be called with the underlying storage of the
pointer rather than with the pointer itself.

This change re-uses the same pattern as
lttng_dynamic_pointer_array_reset(), namely using the destructor
explicitly and setting it to NULL for the duration of the call to
the dynamic array API.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/common/dynamic-array.c b/src/common/dynamic-array.c
index ac2a6d5aa..094e269a4 100644
--- a/src/common/dynamic-array.c
+++ b/src/common/dynamic-array.c
@@ -95,6 +95,28 @@ void lttng_dynamic_pointer_array_init(
 	lttng_dynamic_array_init(&array->array, sizeof(void *), destructor);
 }	
 
+LTTNG_HIDDEN
+int lttng_dynamic_pointer_array_remove_pointer(
+		struct lttng_dynamic_pointer_array *array, size_t index)
+{
+	int ret;
+	const lttng_dynamic_array_element_destructor destructor =
+			array->array.destructor;
+
+	/*
+	 * Prevent the destructor from being used by the underlying
+	 * dynamic array.
+	 */
+	array->array.destructor = NULL;
+	if (destructor) {
+		destructor(lttng_dynamic_pointer_array_get_pointer(array,
+				index));
+	}
+	ret = lttng_dynamic_array_remove_element(&array->array, index);
+	array->array.destructor = destructor;
+	return ret;
+}
+
 /* Release any memory used by the dynamic array. */
 LTTNG_HIDDEN
 void lttng_dynamic_pointer_array_reset(
@@ -108,6 +130,10 @@ void lttng_dynamic_pointer_array_reset(
 					array, i);
 			array->array.destructor(ptr);
 		}
+		/*
+		 * Prevent the destructor from being used by the underlying
+		 * dynamic array.
+		 */
 		array->array.destructor = NULL;
 	}
 	lttng_dynamic_array_reset(&array->array);
diff --git a/src/common/dynamic-array.h b/src/common/dynamic-array.h
index e97b51d5d..1fbc29b70 100644
--- a/src/common/dynamic-array.h
+++ b/src/common/dynamic-array.h
@@ -146,12 +146,9 @@ int lttng_dynamic_pointer_array_add_pointer(
  * count is decreased by one and the following pointers are shifted to
  * take the place of the removed pointer (if applicable).
  */
-static inline
+LTTNG_HIDDEN
 int lttng_dynamic_pointer_array_remove_pointer(
-		struct lttng_dynamic_pointer_array *array, size_t index)
-{
-	return lttng_dynamic_array_remove_element(&array->array, index);
-}
+		struct lttng_dynamic_pointer_array *array, size_t index);
 
 /* Release any memory used by the dynamic array. */
 LTTNG_HIDDEN