While iflag=count_bytes combined with bs > 1 allows for more efficient operation, it is a feature of GNU dd, and not present on other implementations such as BSD. Sticking to just POSIX features makes things more portable. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- docs/nbdkit-loop.pod | 2 +- docs/nbdkit.pod | 4 ++-- plugins/eval/nbdkit-eval-plugin.pod | 6 +++--- plugins/sh/nbdkit-sh-plugin.pod | 2 +- plugins/sh/assemble.sh | 2 +- plugins/sh/example.sh | 7 +++---- tests/test-cacheextents.sh | 5 ++--- tests/test-eval-file.sh | 5 ++--- tests/test-eval.sh | 3 +-- tests/test-export-name.sh | 5 ++--- tests/test-parallel-sh.sh | 5 ++--- tests/test-readahead-test-plugin.sh | 2 +- tests/test-readahead.sh | 1 - tests/test-retry-reopen-fail.sh | 3 +-- tests/test-retry-size.sh | 3 +-- tests/test-retry.sh | 3 +-- tests/test-shell.sh | 5 ++--- tests/test-single-sh.sh | 3 +-- tests/test-tls-fallback.sh | 2 +- 19 files changed, 28 insertions(+), 40 deletions(-) diff --git a/docs/nbdkit-loop.pod b/docs/nbdkit-loop.pod index 055b5750..b21c2212 100644 --- a/docs/nbdkit-loop.pod +++ b/docs/nbdkit-loop.pod @@ -120,7 +120,7 @@ creates a disk which contains a bad sector: echo EIO Bad block >&2 exit 1 else - dd if=/dev/zero count=$3 iflag=count_bytes + dd bs=1 if=/dev/zero count=$3 fi ;; *) exit 2 ;; esac diff --git a/docs/nbdkit.pod b/docs/nbdkit.pod index 98f069f7..67653bc0 100644 --- a/docs/nbdkit.pod +++ b/docs/nbdkit.pod @@ -138,7 +138,7 @@ L<nbdkit-sh-plugin(3)>: nbdkit sh - <<'EOF' case "$1" in get_size) echo 1M ;; - pread) dd if=/dev/zero count=$3 iflag=count_bytes ;; + pread) dd bs=1 if=/dev/zero count=$3 ;; *) exit 2 ;; esac EOF @@ -149,7 +149,7 @@ The same example as above can be written entirely on the command line using L<nbdkit-eval-plugin(1)>: nbdkit eval get_size='echo 1M' \ - pread='dd if=/dev/zero count=$3 iflag=count_bytes' + pread='dd bs=1 if=/dev/zero count=$3' =back diff --git a/plugins/eval/nbdkit-eval-plugin.pod b/plugins/eval/nbdkit-eval-plugin.pod index 7126c6de..d5918e28 100644 --- a/plugins/eval/nbdkit-eval-plugin.pod +++ b/plugins/eval/nbdkit-eval-plugin.pod @@ -51,7 +51,7 @@ all other methods are identical). Create a 64M read-only disk of zeroes: nbdkit eval get_size=' echo 64M ' \ - pread=' dd if=/dev/zero count=$3 iflag=count_bytes ' + pread=' dd bs=1 if=/dev/zero count=$3 ' The following command is the eval plugin equivalent of L<nbdkit-file-plugin(1)> (except not as fast and missing many @@ -60,8 +60,8 @@ features): nbdkit eval \ config='ln -sf "$(realpath "$3")" $tmpdir/file' \ get_size='stat -Lc %s $tmpdir/file' \ - pread='dd if=$tmpdir/file skip=$4 count=$3 iflag=count_bytes,skip_bytes' \ - pwrite='dd of=$tmpdir/file seek=$4 conv=notrunc oflag=seek_bytes' \ + pread='dd bs=1 if=$tmpdir/file skip=$4 count=$3' \ + pwrite='dd bs=1 of=$tmpdir/file seek=$4 conv=notrunc' \ file=disk.img =head1 PARAMETERS diff --git a/plugins/sh/nbdkit-sh-plugin.pod b/plugins/sh/nbdkit-sh-plugin.pod index 07d90b57..70741139 100644 --- a/plugins/sh/nbdkit-sh-plugin.pod +++ b/plugins/sh/nbdkit-sh-plugin.pod @@ -42,7 +42,7 @@ as the name of the script, like this: nbdkit sh - <<'EOF' case "$1" in get_size) echo 1M ;; - pread) dd if=/dev/zero count=$3 iflag=count_bytes ;; + pread) dd bs=1 if=/dev/zero count=$3 ;; *) exit 2 ;; esac EOF diff --git a/plugins/sh/assemble.sh b/plugins/sh/assemble.sh index 5d994857..45b9b698 100755 --- a/plugins/sh/assemble.sh +++ b/plugins/sh/assemble.sh @@ -46,7 +46,7 @@ case "$1" in echo 512 ;; pread) - dd if=$b skip=$4 count=$3 iflag=count_bytes,skip_bytes + dd bs=1 if=$b skip=$4 count=$3 ;; can_write) # Default is yes to make it writable (but writes will fail). diff --git a/plugins/sh/example.sh b/plugins/sh/example.sh index 4f547db0..03249b27 100755 --- a/plugins/sh/example.sh +++ b/plugins/sh/example.sh @@ -117,12 +117,12 @@ case "$1" in pread) # Read the requested part of the disk and write to stdout. - dd iflag=skip_bytes,count_bytes skip=$4 count=$3 if=$f || exit 1 + dd bs=1 skip=$4 count=$3 if=$f || exit 1 ;; pwrite) # Copy data from stdin and write it to the disk. - dd oflag=seek_bytes conv=notrunc seek=$4 of=$f || exit 1 + dd bs=1 conv=notrunc seek=$4 of=$f || exit 1 ;; can_write) @@ -162,8 +162,7 @@ case "$1" in # cache) # Implement an efficient prefetch, if desired. # It is intentionally omitted from this example. - # dd iflag=skip_bytes,count_bytes skip=$4 count=$3 \ - # if=$f of=/dev/null || exit 1 + # dd bs=1 skip=$4 count=$3 if=$f of=/dev/null || exit 1 # ;; can_cache) diff --git a/tests/test-cacheextents.sh b/tests/test-cacheextents.sh index 9580348c..48de9365 100755 --- a/tests/test-cacheextents.sh +++ b/tests/test-cacheextents.sh @@ -1,6 +1,6 @@ #!/usr/bin/env bash # nbdkit -# Copyright (C) 2019 Red Hat Inc. +# Copyright (C) 2019-2020 Red Hat Inc. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are @@ -37,7 +37,6 @@ set -e requires grep --version requires qemu-img --version requires qemu-io --version -requires dd iflag=count_bytes </dev/null sock="$(mktemp -u)" sockurl="nbd+unix:///?socket=$sock" @@ -71,7 +70,7 @@ case "$1" in echo ${i}M $block_size $((i%4)) done ;; - pread) dd if=/dev/zero count=$3 iflag=count_bytes ;; + pread) dd bs=1 if=/dev/zero count=$3 ;; can_write) ;; pwrite) dd of=/dev/null ;; can_trim) ;; diff --git a/tests/test-eval-file.sh b/tests/test-eval-file.sh index 7d6f79d4..d291803f 100755 --- a/tests/test-eval-file.sh +++ b/tests/test-eval-file.sh @@ -39,7 +39,6 @@ set -x requires guestfish --version requires test -f disk -requires dd iflag=count_bytes </dev/null files="eval-file.img" rm -f $files @@ -50,8 +49,8 @@ cp disk eval-file.img nbdkit -fv -U - eval \ config='ln -sf "$(realpath "$3")" $tmpdir/file' \ get_size='stat -Lc %s $tmpdir/file' \ - pread='dd if=$tmpdir/file skip=$4 count=$3 iflag=count_bytes,skip_bytes' \ - pwrite='dd of=$tmpdir/file seek=$4 conv=notrunc oflag=seek_bytes' \ + pread='dd bs=1 if=$tmpdir/file skip=$4 count=$3' \ + pwrite='dd bs=1 of=$tmpdir/file seek=$4 conv=notrunc' \ file=eval-file.img \ --run ' guestfish \ diff --git a/tests/test-eval.sh b/tests/test-eval.sh index 07a9ea1e..212f2836 100755 --- a/tests/test-eval.sh +++ b/tests/test-eval.sh @@ -35,7 +35,6 @@ set -e set -x requires qemu-img --version -requires dd iflag=count_bytes </dev/null files="eval.out eval.missing" rm -f $files @@ -47,7 +46,7 @@ cleanup_fn rm -f $files # nbdkit, and nbdkit shuts down before the .close callback is called. nbdkit -U - eval \ get_size='echo 64M' \ - pread='dd if=/dev/zero count=$3 iflag=count_bytes' \ + pread='dd bs=1 if=/dev/zero count=$3' \ missing='echo "in missing: $@" >> eval.missing; exit 2' \ unload='' \ --run 'qemu-img info $nbd; sleep 10' > eval.out diff --git a/tests/test-export-name.sh b/tests/test-export-name.sh index 5ff0d088..40f2ce18 100755 --- a/tests/test-export-name.sh +++ b/tests/test-export-name.sh @@ -1,6 +1,6 @@ #!/usr/bin/env bash # nbdkit -# Copyright (C) 2019 Red Hat Inc. +# Copyright (C) 2019-2020 Red Hat Inc. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are @@ -35,7 +35,6 @@ set -e set -x requires nbdsh --version -requires dd iflag=count_bytes </dev/null sock=`mktemp -u` files="$sock exportname.pid" @@ -59,7 +58,7 @@ case "$1" in echo ${#2} ;; pread) - printf %s "$2" | dd skip=$4 count=$3 iflag=skip_bytes,count_bytes + printf %s "$2" | dd bs=1 skip=$4 count=$3 ;; *) exit 2 ;; esac diff --git a/tests/test-parallel-sh.sh b/tests/test-parallel-sh.sh index 8d8b9b19..4a26f0a8 100755 --- a/tests/test-parallel-sh.sh +++ b/tests/test-parallel-sh.sh @@ -36,7 +36,6 @@ source ./functions.sh requires test -f file-data requires qemu-io --version requires timeout --version -requires dd iflag=count_bytes </dev/null nbdkit --dump-plugin sh | grep -q ^thread_model=parallel || { echo "nbdkit lacks support for parallel requests"; exit 77; } @@ -87,8 +86,8 @@ fi case \$1 in thread_model) echo parallel ;; get_size) stat -L -c %s \$f || exit 1 ;; - pread) dd iflag=skip_bytes,count_bytes skip=\$4 count=\$3 if=\$f || exit 1 ;; - pwrite) dd oflag=seek_bytes conv=notrunc seek=\$4 of=\$f || exit 1 ;; + pread) dd bs=1 skip=\$4 count=\$3 if=\$f || exit 1 ;; + pwrite) dd bs=1 conv=notrunc seek=\$4 of=\$f || exit 1 ;; can_write) ;; *) exit 2 ;; esac diff --git a/tests/test-readahead-test-plugin.sh b/tests/test-readahead-test-plugin.sh index e8c57c5c..c2af913c 100755 --- a/tests/test-readahead-test-plugin.sh +++ b/tests/test-readahead-test-plugin.sh @@ -40,7 +40,7 @@ case "$1" in ;; pread) sleep 5 - dd if=/dev/zero count=$3 iflag=count_bytes + dd bs=1 if=/dev/zero count=$3 ;; *) exit 2 diff --git a/tests/test-readahead.sh b/tests/test-readahead.sh index b1aabd88..329bcd68 100755 --- a/tests/test-readahead.sh +++ b/tests/test-readahead.sh @@ -40,7 +40,6 @@ set -x requires python3 --version requires python3 -c 'import nbd' -requires dd iflag=count_bytes </dev/null files="readahead.img" rm -f $files diff --git a/tests/test-retry-reopen-fail.sh b/tests/test-retry-reopen-fail.sh index 55704f33..60e579e2 100755 --- a/tests/test-retry-reopen-fail.sh +++ b/tests/test-retry-reopen-fail.sh @@ -40,7 +40,6 @@ set -x fail=0 requires qemu-io --version -requires dd iflag=count_bytes </dev/null files="retry-reopen-fail-count retry-reopen-fail-open-count retry-reopen-fail-status" @@ -96,7 +95,7 @@ case "$1" in echo "EIO pread failed" >&2 exit 1 else - dd if=/dev/zero count=$3 iflag=count_bytes + dd bs=1 if=/dev/zero count=$3 fi ;; diff --git a/tests/test-retry-size.sh b/tests/test-retry-size.sh index ac3daf69..7ddc20ca 100755 --- a/tests/test-retry-size.sh +++ b/tests/test-retry-size.sh @@ -37,7 +37,6 @@ set -x fail=0 requires qemu-io --version -requires dd iflag=count_bytes </dev/null files="retry-size-open-count retry-size-fail" rm -f $files @@ -81,7 +80,7 @@ case "$1" in touch retry-size-fail fi ;; esac - dd if=/dev/zero count=$3 iflag=count_bytes + dd bs=1 if=/dev/zero count=$3 ;; *) exit 2 ;; esac diff --git a/tests/test-retry.sh b/tests/test-retry.sh index 173bd20a..fd2513f9 100755 --- a/tests/test-retry.sh +++ b/tests/test-retry.sh @@ -35,7 +35,6 @@ set -e set -x requires qemu-img --version -requires dd iflag=count_bytes </dev/null files="retry.img retry-count retry-open-count" rm -f $files @@ -65,7 +64,7 @@ case "$1" in echo "EIO pread failed" >&2 exit 1 else - dd if=/dev/zero count=$3 iflag=count_bytes + dd bs=1 if=/dev/zero count=$3 fi ;; diff --git a/tests/test-shell.sh b/tests/test-shell.sh index 028b8b9c..9bf00204 100755 --- a/tests/test-shell.sh +++ b/tests/test-shell.sh @@ -41,8 +41,7 @@ case "$1" in ;; pread) - dd iflag=skip_bytes,count_bytes skip=$4 count=$3 if=$f || \ - exit 1 + dd bs=1 skip=$4 count=$3 if=$f || exit 1 ;; pwrite) @@ -51,7 +50,7 @@ case "$1" in *) echo "garbage flags: '$5'" >&2 exit 1; esac - dd oflag=seek_bytes conv=notrunc seek=$4 of=$f || exit 1 + dd bs=1 conv=notrunc seek=$4 of=$f || exit 1 ;; can_write) ;; diff --git a/tests/test-single-sh.sh b/tests/test-single-sh.sh index 63f38dff..0342e712 100755 --- a/tests/test-single-sh.sh +++ b/tests/test-single-sh.sh @@ -35,7 +35,6 @@ set -e set -x requires nbdsh --version -requires dd iflag=count_bytes </dev/null files="single-sh.script single-sh.log" rm -f $files @@ -60,7 +59,7 @@ fi cat >single-sh.script <<\EOF case $1 in get_size) echo 1m ;; - pread) dd if=/dev/zero count=$3 iflag=count_bytes ;; + pread) dd bs=1 if=/dev/zero count=$3 ;; *) exit 2 ;; esac EOF diff --git a/tests/test-tls-fallback.sh b/tests/test-tls-fallback.sh index 4b48c1cb..ededae39 100755 --- a/tests/test-tls-fallback.sh +++ b/tests/test-tls-fallback.sh @@ -71,7 +71,7 @@ case $1 in fi echo $3 ;; get_size) echo "$2" | wc -c ;; - pread) echo "$2" | dd skip=$4 count=$3 iflag=skip_bytes,count_bytes ;; + pread) echo "$2" | dd bs=1 skip=$4 count=$3 ;; can_write | can_trim) exit 0 ;; *) exit 2 ;; esac -- 2.28.0