diff options
| -rwxr-xr-x | tests/dd/reblock | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/tests/dd/reblock b/tests/dd/reblock index ef9e03613..7631acc19 100755 --- a/tests/dd/reblock +++ b/tests/dd/reblock @@ -24,12 +24,14 @@ fi . $srcdir/lang-default . $srcdir/test-lib.sh +# 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 (4 B) copied EOF +# 2 short reads -> 2 partial writes cat <<\EOF > exp-no-reblock || framework_failure 0+2 records in 0+2 records out @@ -38,16 +40,24 @@ EOF fail=0 +# 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 dd.fifo || framework_failure + # ensure that dd reblocks when bs= is not specified -(echo x; sleep .1; echo y) | dd ibs=3 obs=3 > out 2> err || fail=1 +dd ibs=3 obs=3 if=dd.fifo > out 2> err& +(printf 'ab'; sleep .2; printf 'cd') > dd.fifo +wait #for dd to complete sed 's/,.*//' err > k && mv k err compare err exp-reblock || fail=1 # Demonstrate that bs=N supersedes even following ibs= and obs= settings. -# Choosing a delay of 0.1 would result in an occasional lost race where -# the consumer's first read would consume 3 bytes rather than the expected 2. -# Not wanting to sleep a full second, I'll raise that to 0.3. -(printf ab; sleep .3; printf cd) | dd bs=3 ibs=1 obs=1 > out 2> err || fail=1 +dd bs=3 ibs=1 obs=1 if=dd.fifo > out 2> err& +(printf 'ab'; sleep .2; printf 'cd') > dd.fifo +wait #for dd to complete sed 's/,.*//' err > k && mv k err compare err exp-no-reblock || fail=1 |