72 lines
2 KiB
Bash
Executable file
72 lines
2 KiB
Bash
Executable file
#!/bin/sh
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# test dd reblocking vs. bs=
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# Copyright (C) 2008-2025 Free Software Foundation, Inc.
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
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print_ver_ dd
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# 2 short reads -> 1 full write + 1 partial write
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cat <<\EOF > exp-reblock || framework_failure_
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0+2 records in
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1+1 records out
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4 bytes copied
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EOF
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# 2 short reads -> 2 partial writes
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cat <<\EOF > exp-no-reblock || framework_failure_
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0+2 records in
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0+2 records out
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4 bytes copied
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EOF
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# Use a fifo rather than a pipe in the tests below
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# so that the producer (printf subshell) will wait
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# until the consumer (dd) opens the fifo therefore
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# increasing the chance that dd will read the data
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# from each printf separately.
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mkfifo_or_skip_ dd.fifo
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dd_reblock_1()
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{
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local delay="$1"
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# ensure that dd reblocks when bs= is not specified
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dd ibs=3 obs=3 if=dd.fifo > out 2> err&
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(printf 'ab'; sleep $delay; printf 'cd') > dd.fifo
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wait #for dd to complete
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sed 's/,.*//' err > k && mv k err
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compare exp-reblock err
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}
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retry_delay_ dd_reblock_1 .1 6 || fail=1
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dd_reblock_2()
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{
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local delay="$1"
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# Demonstrate that bs=N supersedes even following ibs= and obs= settings.
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dd bs=3 ibs=1 obs=1 if=dd.fifo > out 2> err&
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(printf 'ab'; sleep $delay; printf 'cd') > dd.fifo
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wait #for dd to complete
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sed 's/,.*//' err > k && mv k err
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compare exp-no-reblock err
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}
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retry_delay_ dd_reblock_2 .1 6 || fail=1
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Exit $fail
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