+/**
+ * os_memcmp_const - Constant time memory comparison
+ * @a: First buffer to compare
+ * @b: Second buffer to compare
+ * @len: Number of octets to compare
+ * Returns: 0 if buffers are equal, non-zero if not
+ *
+ * This function is meant for comparing passwords or hash values where
+ * difference in execution time could provide external observer information
+ * about the location of the difference in the memory buffers. The return value
+ * does not behave like os_memcmp(), i.e., os_memcmp_const() cannot be used to
+ * sort items into a defined order. Unlike os_memcmp(), execution time of
+ * os_memcmp_const() does not depend on the contents of the compared memory
+ * buffers, but only on the total compared length.
+ */
+int os_memcmp_const(const void *a, const void *b, size_t len);
+
+/**
+ * os_exec - Execute an external program
+ * @program: Path to the program
+ * @arg: Command line argument string
+ * @wait_completion: Whether to wait until the program execution completes
+ * Returns: 0 on success, -1 on error
+ */
+int os_exec(const char *program, const char *arg, int wait_completion);
+