On 12/14/18 4:16 PM, Richard W.M. Jones wrote:
--- tests/Makefile.am | 3 + tests/test-eflags.sh | 222 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 225 insertions(+)
+# Test export flags. +# +# Run nbdkit with various can_* callbacks defined and with or without +# the -r flag, and check that nbdkit constructs the export flags +# controlling READ_ONLY, ROTATIONAL, SEND_TRIM, etc. as expected. +# +# We use the oldstyle (-o) protocol here because it's simpler to read +# out the eflags.
Indeed - the client has to talk in newstyle, but not in oldstyle :)
We use the shell plugin because it gives maximum +# control over the can_* callbacks (at least, max without having to +# write a C plugin). + +source ./functions.sh +set -e + +if ! socat -h >/dev/null; then + echo "$0: 'socat' command not available" + exit 77 +fi + +# Check 'od' command exists and can do endian swaps (which the FreeBSD +# version cannot).
Do we need endian swaps, or can we just read one byte at a time and then reconstruct things by hand (after all, we know the bytes are in network order, so we don't have to worry about whether we are running on a big- or little-endian machine to do the integer math to build up the 16-bit value from those two bytes).
+if ! od --endian=big </dev/null >/dev/null; then + echo "$0: 'od' command not available or doesn't support endian swaps" + exit 77 +fi + +files="eflags.out" +rm -f $files +cleanup_fn rm -f $files + +# The export flags. +# See also src/protocol.h
Comment may need tweaking if I finish my patches to move src/proto* to common/proto/. We'll see what lands first :)
+HAS_FLAGS=$(( 1 << 0 )) +READ_ONLY=$(( 1 << 1 )) +SEND_FLUSH=$(( 1 << 2 )) +SEND_FUA=$(( 1 << 3 )) +ROTATIONAL=$(( 1 << 4 )) +SEND_TRIM=$(( 1 << 5 )) +SEND_WRITE_ZEROES=$(( 1 << 6 )) + +all_flags="HAS_FLAGS READ_ONLY SEND_FLUSH SEND_FUA ROTATIONAL SEND_TRIM SEND_WRITE_ZEROES"
Well, that's all the flags we currently drive, although more flags exist (and we may eventually patch nbdkit to drive those, as well).
+ +do_nbdkit () +{ + nbdkit -v -U - -o "$@" sh script=- --run ' + socat -b 28 unix-connect:$unixsocket \ + exec:"dd bs=1 skip=26 count=2 of=eflags.out status=none"
dd can portably do byteswaps, with conv=swab, but then you have to know if you are big- or little-endian to know whether to use it.
+ ' + + # By adding 0 we convert the string to an integer (removing + # whitespace). + eflags=$((0 + $(od --endian=big -An -N2 -d < eflags.out)))
So back to my earlier thought of just reading 1 byte at a time and building up the value ourselves: eflags=$(( ($(od -An -N1 -tu1 eflags.out) << 8) | $(od -An -N1 -j1 -tu1 eflags.out) ))
+ printf "eflags 0x%04x" $eflags + for f in $all_flags; do + [ $(( eflags & ${!f} )) -ne 0 ] && echo -n " $f" + done + echo +} +
+ +# no -r +# can_write=true +# +# NBD_FLAG_SEND_WRITE_ZEROES is always set on writable connections +# even if can_zero returns false, because nbdkit reckons it can +# emulate zeroing using pwrite.
And we have the nozero filter if we want things otherwise (if you want to use that in this test). Otherwise, this looks sane. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org