1 files changed, 72 insertions, 0 deletions
diff --git a/tests/dd/reblock.sh b/tests/dd/reblock.sh
new file mode 100755
index 0000000..ce3716c
--- /dev/null
+++ b/tests/dd/reblock.sh
@@ -0,0 +1,72 @@
+#!/bin/sh
+# test dd reblocking vs. bs=
+
+# Copyright (C) 2008-2022 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
+
+# 2 short reads -> 1 full write + 1 partial write
+cat <<\EOF > exp-reblock || framework_failure_
+0+2 records in
+1+1 records out
+4 bytes copied
+EOF
+
+# 2 short reads -> 2 partial writes
+cat <<\EOF > exp-no-reblock || framework_failure_
+0+2 records in
+0+2 records out
+4 bytes copied
+EOF
+
+
+# Use a fifo rather than a pipe in the tests below
+# so that the producer (printf subshell) will wait
+# until the consumer (dd) opens the fifo therefore
+# increasing the chance that dd will read the data
+# from each printf separately.
+mkfifo_or_skip_ dd.fifo
+
+dd_reblock_1()
+{
+  local delay="$1"
+
+  # ensure that dd reblocks when bs= is not specified
+  dd ibs=3 obs=3 if=dd.fifo > out 2> err&
+  (printf 'ab'; sleep $delay; printf 'cd') > dd.fifo
+  wait #for dd to complete
+  sed 's/,.*//' err > k && mv k err
+  compare exp-reblock err
+}
+
+retry_delay_ dd_reblock_1 .1 6 || fail=1
+
+dd_reblock_2()
+{
+  local delay="$1"
+
+  # Demonstrate that bs=N supersedes even following ibs= and obs= settings.
+  dd bs=3 ibs=1 obs=1 if=dd.fifo > out 2> err&
+  (printf 'ab'; sleep $delay; printf 'cd') > dd.fifo
+  wait #for dd to complete
+  sed 's/,.*//' err > k && mv k err
+  compare exp-no-reblock err
+}
+
+retry_delay_ dd_reblock_2 .1 6 || fail=1
+
+Exit $fail