[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit

Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/app/busybox/src/libbb/full_write.c b/ap/app/busybox/src/libbb/full_write.c
new file mode 100644
index 0000000..777fbd9
--- /dev/null
+++ b/ap/app/busybox/src/libbb/full_write.c
@@ -0,0 +1,42 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+
+#include "libbb.h"
+
+/*
+ * Write all of the supplied buffer out to a file.
+ * This does multiple writes as necessary.
+ * Returns the amount written, or -1 on an error.
+ */
+ssize_t FAST_FUNC full_write(int fd, const void *buf, size_t len)
+{
+	ssize_t cc;
+	ssize_t total;
+
+	total = 0;
+
+	while (len) {
+		cc = safe_write(fd, buf, len);
+
+		if (cc < 0) {
+			if (total) {
+				/* we already wrote some! */
+				/* user can do another write to know the error code */
+				return total;
+			}
+			return cc;  /* write() returns -1 on failure. */
+		}
+
+		total += cc;
+		buf = ((const char *)buf) + cc;
+		len -= cc;
+	}
+
+	return total;
+}