vold: Add an optional wipe paramter to the volume format command

The new wipe option to the vold format command will invoke BLKDISCARD
on the partition before invoking newfs_msdos.  This will be used whenever
a full wipe of the device is wanted, as this is more secure than just
doing newfs_msdos.

Bug: 9392982
Change-Id: Ie106f1b9cc70abc61206006d1821641c27c7ccae
diff --git a/VoldUtil.c b/VoldUtil.c
new file mode 100644
index 0000000..b5f9946
--- /dev/null
+++ b/VoldUtil.c
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sys/ioctl.h>
+#include <linux/fs.h>
+
+unsigned int get_blkdev_size(int fd)
+{
+  unsigned int nr_sec;
+
+  if ( (ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) {
+    nr_sec = 0;
+  }
+
+  return nr_sec;
+}