dd: create a sparse file when seek=N is used

When the seek=N argument is used mark the file as sparse and set
the range that is sparse.

See https://stackoverflow.com/questions/4011508/how-to-create-a-sparse-file-on-ntfs

1 files changed, 3 insertions, 0 deletions

diff --git a/coreutils/dd.c b/coreutils/dd.c
index 3054ec6ea..fc8b1dbb2 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -502,6 +502,9 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
         }
         if (seek) {
                 size_t blocksz = (G.flags & FLAG_SEEK_BYTES) ? 1 : obs;
+#if ENABLE_PLATFORM_MINGW32
+                seek_sparse(ofd, seek * blocksz);
+#endif
                 if (lseek(ofd, seek * blocksz, SEEK_CUR) < 0)
                         goto die_outfile;
         }