Fix: liblttng-ctl: unchecked return value on buffer append

[lttng-tools.git] / src / common / dynamic-array.h

diff --git a/src/common/dynamic-array.h b/src/common/dynamic-array.h
index 1fbc29b70ac06285a30fc4ac21c60a5f081165af..0b488a39cd52f95b785f2f3a52ee48f6c3e9cd0b 100644 (file)
--- a/src/common/dynamic-array.h
+++ b/src/common/dynamic-array.h
@@ -1,18 +1,8 @@
 /*
- * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License, version 2.1 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
- * for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifndef LTTNG_DYNAMIC_ARRAY_H
@@ -66,6 +56,25 @@ void *lttng_dynamic_array_get_element(const struct lttng_dynamic_array *array,
        return array->buffer.data + (element_index * array->element_size);
 }
 
+/*
+ * Set the array's element count to new_element_count. Any added element will
+ * be zeroed.
+ *
+ * Be careful to expand the array's element count _before_ calling out external
+ * APIs (e.g. read(3)) which may populate the buffer as setting the element
+ * count after will zero-out the result of the operation.
+ *
+ * Shrinking an array does not zero the old content. If the buffer may contain
+ * sensititve information, it must be cleared manually _before_ changing the
+ * size.
+ *
+ * NOTE: It is striclty _invalid_ to access memory after _size_, regardless
+ *       of prior calls to set_capacity().
+ */
+LTTNG_HIDDEN
+int lttng_dynamic_array_set_count(struct lttng_dynamic_array *array,
+               size_t new_element_count);
+
 /*
  * Add an element to the end of a dynamic array. The array's element count is
  * increased by one and its underlying capacity is adjusted automatically.
@@ -89,6 +98,9 @@ int lttng_dynamic_array_remove_element(struct lttng_dynamic_array *array,
 LTTNG_HIDDEN
 void lttng_dynamic_array_reset(struct lttng_dynamic_array *array);
 
+/* Remove all elements from the dynamic array. */
+LTTNG_HIDDEN
+void lttng_dynamic_array_clear(struct lttng_dynamic_array *array);
 
 /*
  * Specialization of lttng_dynamic_array for pointers. This utility
@@ -117,8 +129,7 @@ size_t lttng_dynamic_pointer_array_get_count(
 }
 
 /*
- * Returns a pointer to the element. Mutating operations on the array invalidate
- * the returned pointer.
+ * Returns the pointer at index `index`.
  */
 static inline
 void *lttng_dynamic_pointer_array_get_pointer(
@@ -155,4 +166,9 @@ LTTNG_HIDDEN
 void lttng_dynamic_pointer_array_reset(
                struct lttng_dynamic_pointer_array *array);
 
+/* Remove all elements from the dynamic pointer array. */
+LTTNG_HIDDEN
+void lttng_dynamic_pointer_array_clear(
+               struct lttng_dynamic_pointer_array *array);
+
 #endif /* LTTNG_DYNAMIC_ARRAY_H */