Add samsung specific changes

include/kunit/strerror.h

@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * C++ stream style string formatter and printer used in KUnit for outputting
+ * KUnit messages.
+ *
+ * Copyright (C) 2019, Google LLC.
+ * Author: Mike Krinkin <krinkin@google.com>
+ */
+#include <linux/types.h>
+
+/**
+ * strerror() - returns a string representation for the given error code.
+ * @errno: an error code defined in include/uapi/asm-generic/errno-base.h or
+ * include/uapi/asm-generic/errno.h
+ *
+ * This function returns mnemonic representation of error code (for example,
+ * EPERM, ENOENT, ESRCH, etc). For unsupported errors this function returns
+ * NULL.
+ */
+const char *strerror_str(int errno);
+
+/**
+ * strerror_r() - returns a string representation of the given error code.
+ * Unlike strerror() it may use provided buffer to store the string, so in
+ * the case of unknown error it returns a message containing an error code
+ * instead of returning NULL.
+ * @errno: an error code defined in include/uapi/asm-generic/errno-base.h or
+ * include/uapi/asm-generic/errno.h
+ * @buf: pointer to a buffer that could be used to store the string.
+ * @buflen: contains the capacity of the buffer
+ *
+ * When function uses provided buffer and it's capacity is not enough to
+ * store the whole string the string is truncated and always contains '\0'.
+ * If buflen == 0, the function returns NULL pointer as there is not enough
+ * space to store even '\0'.
+ */
+const char *strerror_r(int errno, char *buf, size_t buflen);