Non-regular file removal test fails on GNU/Hurd

[mestia]

While building zstd on GNU/Hurd the following test fail:

skip>

test : file removal

Read : 0 / 0 MB ==> 32%

tmp : 32.42% ( 65537 => 21246 bytes, tmp.zst)

tmp.zst : 0 MB...

tmp.zst : 65537 bytes
test : should quietly not remove non-regular file
Makefile:306: recipe for target 'zstd-playTests' failed
make[3]: *** [zstd-playTests] Error 1

The complete build log lives here.
Any idea what might be wrong there? Thanks!

[terrelln]

@mestia does /dev/zero exist on GNU/Hurd?

We need to test writing to some non-regular that isn't /dev/null, since we special case /dev/null.

If /dev/zero doesn't exist, we need to add another case here to special case GNU/Hurd, and it must be a non-regular file (where this line gets triggered).

[mestia]

@terrelln /dev/zero exists:

ls -l /dev/null
crw-rw-rw- 1 root root 0, 0 Jun 12  2017 /dev/null
file /dev/zero                                                                                                                                                                                                    :(
/dev/zero: character special (0/0)

Looking on the test more precisely, i realized that $INTONUL variable is not defined. Could it be a typo?
Apart from that all works as expected:

root@hurd /tmp/xx # export INTOVOID="/dev/null"
root@hurd /tmp/xx # export DEVDEVICE="/dev/zero"
root@hurd /tmp/xx # export ZSTD=~/pkg/libzstd/programs/zstd
root@hurd /tmp/xx # echo hello >tmp
root@hurd /tmp/xx # $ZSTD tmp -f -o "$DEVDEVICE" 2>tmplog > "$INTOVOID"
1 root@hurd /tmp/xx # cat tmplog                                                                                                                                                                                                        :(
tmp                  :316.67%   (     6 =>     19 bytes, /dev/zero)
zstd: /dev/zero: (os/kern) successful
zstd: Refusing to remove non-regular file /dev/zero
root@hurd /tmp/xx # rm -f tmplog
root@hurd /tmp/xx # $ZSTD tmp -f -o "$INTONULL" 2>&1 | grep -v "Refusing to remove non-regular file"
zstd: : No such file or directory

I wonder now, why it is working on all other architectures.

[terrelln]

Nice catch! It should be $INTOVOID. Since the grep succeeds the pipeline exits zero, but I guess GNU/Hurd still fails when zstd fails but grep succeeds.

[mestia]

Sorry for coming back, but I realized that the actual issue is still there.

$ZSTD tmp -f -o /dev/zero; echo $?
tmp                  :316.67%   (     6 =>     19 bytes, /dev/zero)
zstd: /dev/zero: (os/kern) successful
zstd: Refusing to remove non-regular file /dev/zero
1

The test in the line 176 fails.

Simply echoing to /dev/zero on Gnu/Hurd produces the same error:

echo test > /dev/zero; echo $? 
echo: write error: (os/kern) successful
1

I guess this is some kernel specific feature on this architecture.
On amd64 host it works just fine.
A non-regular files where writing not causing errors on Hurd are /dev/random or /dev/urandom, though not sure if it is correct to write to these files.

[terrelln]

Thanks @mestia, that should work. Writing to /dev/random seeds the entropy pool, so it is perfectly fine.