ext4_utils: Add support for wipe option, and wipe by default in recovery
Adds a -w option to make_ext4fs, which will attempt to use the
BLKSECDISCARD ioctl to erase the partition in order to avoid
leaving old data where it could be recovered, and to improve
wear levelling after a reformat.
Also causes factory reset through recovery to do a wipe.
Change-Id: Ibe34bbd84552e526be6bd041024a950806aca6b4
diff --git a/ext4_utils/wipe.c b/ext4_utils/wipe.c
new file mode 100644
index 0000000..c7ba6db
--- /dev/null
+++ b/ext4_utils/wipe.c
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2011 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 "ext4_utils.h"
+#include "wipe.h"
+
+#if defined(__linux__)
+
+#include <linux/fs.h>
+#include <sys/ioctl.h>
+
+#ifndef BLKDISCARD
+#define BLKDISCARD _IO(0x12,119)
+#endif
+
+#ifndef BLKSECDISCARD
+#define BLKSECDISCARD _IO(0x12,125)
+#endif
+
+int wipe_block_device(int fd, int len)
+{
+ u64 range[2];
+ int ret;
+
+ range[0] = 0;
+ range[1] = len;
+ ret = ioctl(fd, BLKSECDISCARD, &range);
+ if (ret < 0) {
+ range[0] = 0;
+ range[1] = len;
+ ret = ioctl(fd, BLKDISCARD, &range);
+ if (ret < 0) {
+ error("Discard failed\n");
+ return 1;
+ } else {
+ warn("Wipe via secure discard failed, used discard instead\n");
+ return 0;
+ }
+ }
+
+ return 0;
+}
+#else
+int wipe_block_device(int fd)
+{
+ error("wipe not supported on non-linux platforms");
+ return 1;
+}
+#endif
+