blkdiscard: new command

1 files changed, 78 insertions, 0 deletions

diff --git a/toys/pending/blkdiscard.c b/toys/pending/blkdiscard.c
new file mode 100644
index 00000000..1f0c09cd
--- /dev/null
+++ b/toys/pending/blkdiscard.c
@@ -0,0 +1,78 @@
+/* blkdiscard - discard device sectors
+ *
+ * Copyright 2020 Patrick Oppenlander <patrick.oppenlander@gmail.com>
+ *
+ * See https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/tree/sys-utils/blkdiscard.8
+ *
+ * These options are not supported:
+ * -v, --verbose
+ * -p, --step
+ * -V, --version
+ *
+ * Size parsing does not match util-linux where MB, GB, TB are multiples of
+ * 1000 and MiB, TiB, GiB are multipes of 1024.
+
+USE_BLKDISCARD(NEWTOY(blkdiscard, "<1>1f(force)l(length):o(offset):s(secure)z(zeroout)", TOYFLAG_BIN))
+
+config BLKDISCARD
+  bool "blkdiscard"
+  default n
+  help
+    usage: blkdiscard [options] device
+
+    Discard device sectors.
+
+    -o, --offset OFF	Byte offset from which to start discarding
+    -l, --length LEN	Number of bytes to discard
+    -s, --secure		Perform secure discard
+    -z, --zeroout		Zero-fill rather than discard
+    -f, --force		Disable checking for mounted filesystem
+
+    By default OFF is zero and LEN is the device size meaning that the entire
+    device will be discarded.
+
+    OFF and LEN must be aligned to the device sector size.
+
+    WARNING: All discarded data will be permanently lost!
+*/
+
+#define FOR_blkdiscard
+#include "toys.h"
+
+#include <linux/fs.h>
+
+GLOBALS(
+  char *offset, *length;
+)
+
+void blkdiscard_main(void)
+{
+  int fd, req = BLKDISCARD;
+  uint64_t off = 0, len;
+
+  fd = xopen(toys.optargs[0], O_WRONLY | (FLAG(f) ? 0 : O_EXCL));
+
+  if (FLAG(o)) off = atolx_range(TT.offset, 0, LLONG_MAX);
+
+  if (FLAG(l)) len = atolx_range(TT.length, 0, LLONG_MAX);
+  else {
+    if (ioctl(fd, BLKGETSIZE64, &len) < 0) {
+      perror_msg("ioctl %x", (int)BLKGETSIZE64);
+      goto out;
+    }
+    len -= off;
+  }
+
+  if (FLAG(s) && FLAG(z)) {
+    error_msg("secure and zeroout are mutually exclusive");
+    goto out;
+  }
+  if (FLAG(s)) req = BLKSECDISCARD;
+  if (FLAG(z)) req = BLKZEROOUT;
+
+  if (ioctl(fd, req, (uint64_t[]){off, len}) < 0)
+    perror_msg("ioctl %x", req);
+
+out:
+  if (CFG_TOYBOX_FREE) close(fd);
+}