| # Copyright (C) 2012-2025 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. | |
| # Also, ZFS allocation reports can be delayed or off (problem | |
| # observed on Ubuntu 23.10), so don’t trust this test on ZFS. | |
| if test $(kb_alloc file.in) -gt 3000 && test "$(stat -f -c %T file.in)" != zfs | |
| 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 | |