1 files changed, 93 insertions, 0 deletions
diff --git a/tests/dd/sparse.sh b/tests/dd/sparse.sh
new file mode 100755
index 0000000..87477a0
--- /dev/null
+++ b/tests/dd/sparse.sh
@@ -0,0 +1,93 @@
+#!/bin/sh
+
+# Copyright (C) 2012-2022 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ dd
+is_local_dir_ . || very_expensive_
+require_sparse_support_
+
+# Ensure basic sparse generation works
+truncate -s1M sparse
+dd bs=32K if=sparse of=sparse.dd conv=sparse
+test $(stat -c %s sparse) = $(stat -c %s sparse.dd) || fail=1
+
+# Demonstrate that conv=sparse with oflag=append,
+# will do ineffective seeks in the output
+printf 'a\000\000b' > file.in
+printf 'ab' > exp
+dd if=file.in bs=1 conv=sparse oflag=append > out
+compare exp out || fail=1
+
+# Demonstrate conv=sparse with conv=notrunc,
+# where data in file.out is not overwritten with NULs
+printf '____' > out
+printf 'a__b' > exp
+dd if=file.in bs=1 conv=sparse,notrunc of=out
+compare exp out || fail=1
+
+# Ensure we fall back to write if seek fails
+dd if=file.in bs=1 conv=sparse | cat > file.out
+cmp file.in file.out || fail=1
+
+# Setup for block size tests: create a 3MiB file with a 1MiB
+# stretch of NUL bytes in the middle.
+rm -f file.in
+dd if=/dev/urandom of=file.in bs=1M count=3 iflag=fullblock || fail=1
+dd if=/dev/zero    of=file.in bs=1M count=1 seek=1 conv=notrunc || fail=1
+
+kb_alloc() { du -k "$1"|cut -f1; }
+
+# sync out data for async allocators like NFS/BTRFS
+# sync file.in || fail=1
+
+# If our just-created input file appears to be too small,
+# skip the remaining tests.  On at least Solaris 10 with NFS,
+# file.in is reported to occupy <= 1KiB for about 50 seconds
+# after its creation.
+if test $(kb_alloc file.in) -gt 3000; then
+
+  # Ensure NUL blocks smaller than the *output* block size are not made sparse.
+  # Here, with a 2MiB block size, dd's conv=sparse must *not* introduce a hole.
+  dd if=file.in of=file.out ibs=1M obs=2M conv=sparse || fail=1
+
+  # Intermittently BTRFS returns 0 allocation for file.out unless synced
+  sync file.out || framework_failure_
+  test 2500 -lt $(kb_alloc file.out) || fail=1
+
+  # Note we recreate a sparse file first to avoid
+  # speculative preallocation seen in XFS, where a write() that
+  # extends a file can preallocate some extra space that
+  # a subsequent seek will not convert to a hole.
+  rm -f file.out
+  truncate --size=3M file.out
+
+  # Ensure that this 1MiB *output* block of NULs *is* converted to a hole.
+  dd if=file.in of=file.out ibs=2M obs=1M conv=sparse,notrunc
+  if test $(kb_alloc file.out) -ge 2500; then
+    # Double check the failure by creating a sparse file in
+    # the traditional manner for comparison, as we're not guaranteed
+    # that seek=1M will create a hole.  apfs on darwin 19.2.0 for example
+    # was seen to not to create holes < 16MiB.
+    dd if=file.in of=manual.out bs=1M count=1 || fail=1
+    dd if=file.in of=manual.out bs=1M count=1 seek=2 conv=notrunc || fail=1
+
+    test $(kb_alloc file.out) -eq $(kb_alloc manual.out) || fail=1
+  fi
+
+fi
+
+Exit $fail