[erlang-questions] ftp lib behaviour has changed between ftp-1.0.1 and ftp-1.0.2

[Robert Raschke]

Hi Ingela,

the server I see this behaviour on is: Pure-FTPd - http://pureftpd.org/

If I can find the time, I will try to raise a report. Might take a bit.
Also, the ftp server is not mine, but a live commercial installation. So
I'm not sure about the parameters of their installation or if I can ever
find out.

Cheer,
Robby


On Fri, 12 Jul 2019 at 11:52, Ingela Andin <ingela.andin@REDACTED> wrote:

> Hi Robert!
>
> Can you provide a reliable way to reproduce the problem it will help
> getting it fixed. Have you tried to run our ftp test suite?
> It passes in our tests runs.  The possible bug might be server dependent.
>
> Could you report it at https://bugs.erlang.org/
>
> Regards Ingela Erlang/OTP Team - Ericsson AB
>
> Den fre 12 juli 2019 kl 10:43 skrev Robert Raschke <
> rtrlists@REDACTED>:
>
>> Hi Ingela,
>>
>> I just had a case of ftp:recv_bin(FTP, "filename") repeatedly returned
>> only 'ok'.
>> That is, my hoped for workaround of simply retrying the operation fails.
>>
>> This makes version 1.0.2 of the ftp lib unusable, I'm afraid.
>> I will have to revert to an earlier version.
>>
>> Cheers,
>> Robby
>>
>>
>> On Tue, 9 Jul 2019 at 20:49, Ingela Andin <ingela.andin@REDACTED> wrote:
>>
>>> Hi Robert!
>>>
>>> Well it somewhat unexpected that it returns an undocumented value. It
>>> might be that the correction made to fix a timing bug in the FTP
>>> application, that
>>> was exposed by TLS optimizations when running FTP over TLS, uncovered
>>> some other timing bug. Most of the FTP code is very old and I wished for
>>> the gen_statem behavior while fixing the bug I just mentioned, so I would
>>> not be very surprised if there are more race conditions in that code.
>>>
>>> Regards Ingela Erlang/OTP team
>>>
>>> Den mån 8 juli 2019 kl 18:11 skrev Robert Raschke <
>>> rtrlists@REDACTED>:
>>>
>>>> Hi,
>>>>
>>>> I have code that matches on {ok, Result} and {error, Reason} tuples
>>>> coming from calls to ftp:ls/2 and ftp:recv_bin/2 (on 21.1, ftp-1.0.1) and
>>>> upgrading to 21.3 (ftp-1.0.2) sometimes returns a simple ok on those calls.
>>>> This is surprising.
>>>>
>>>> 15> f().
>>>>
>>>> ok
>>>>
>>>> 16> {ok, FTP} = ftp:open("somesite"), ok = ftp:user(FTP, "someuser",
>>>> "somepwd"), timer:sleep(100), R = ftp:ls(FTP, "/somefolder/*"),
>>>> ftp:close(FTP), R.
>>>>
>>>> {ok,"-rw-r--r--    1 2001       2001           174993 Jul  8 17:16
>>>> ..."}
>>>>
>>>> 17> f().
>>>>
>>>> ok
>>>>
>>>> 18> {ok, FTP} = ftp:open("somesite"), ok = ftp:user(FTP, "someuser",
>>>> "somepwd"), timer:sleep(100), R = ftp:ls(FTP, "/somefolder/*"),
>>>> ftp:close(FTP), R.
>>>>
>>>> ok
>>>>
>>>> 19>
>>>>
>>>>
>>>> What might be the reason for this? And is this expected?
>>>>
>>>>
>>>> Cheers,
>>>>
>>>> Robby
>>>>
>>>>
>>>> _______________________________________________
>>>> erlang-questions mailing list
>>>> erlang-questions@REDACTED
>>>> http://erlang.org/mailman/listinfo/erlang-questions
>>>>
>>>
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