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#!/bin/sh
# Copyright (C) 2012 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 <http://www.gnu.org/licenses/>.
. "${srcdir=.}/init.sh"; path_prepend_ ../src
print_ver_ dd
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
dd if=/dev/urandom of=file.in bs=1M count=1
truncate -s+1M file.in
dd if=/dev/urandom of=file.in bs=1M count=1 conv=notrunc oflag=append
# Note the block allocations below are usually equal,
# but can vary by a file system block due to alignment,
# which was seen on XFS at least.
alloc_equal() {
: ${sectors_per_block:=$(expr $(stat -f -c "%S" .) / 512)}
alloc_diff=$(expr $(stat -c %b "$1") - $(stat -c %b "$2"))
alloc_diff=$(echo $alloc_diff | tr -d -- -) # abs()
test $alloc_diff -le $sectors_per_block
}
# Ensure NUL blocks smaller than the block size are not made sparse
dd if=file.in of=file.out bs=2M conv=sparse
test $(stat -c %s file.in) = $(stat -c %s file.out) || fail=1
alloc_equal file.in file.out && fail=1
# Ensure NUL blocks >= block size are made sparse
dd if=file.in of=file.out bs=1M conv=sparse
test $(stat -c %s file.in) = $(stat -c %s file.out) || fail=1
alloc_equal file.in file.out || fail=1
Exit $fail
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