IMAP preauth and stats-writer

[John Fawcett]

On 06/01/2019 11:37, Stephan Bosch wrote:
>
> Op 06/01/2019 om 03:35 schreef John Fawcett:
>> On 06/01/2019 02:26, John Fawcett wrote:
>>
>>> Can't see anything in the Dovecot 2.3.4 code that would give this
>>> problem, setting
>>>
>>> stats_writer_socket_path =
>>>
>>> will overwrite the default value and dovecot does not attempt to
>>> open a socket in that case.
>>>
>>> Using your configuration (though not FreeBSD) I don't get the
>>> net_connect_unix error whether I use a blank setting or leave the
>>> default. In the case of leaving the default I do get an additional
>>> process (dovecot/stats). No errors on connecting to the imap service
>>> or by running preauth (with the dovecot daemon already running).
>>>
>>> The net_connect_unix() error with a zero length socket name is
>>> inexplicable to me, unless it's got a non printing character in it
>>> or there is something different happening on FreeBSD.
>>>
>>> One suggestion is to run with the default setting, but look at
>>> resolving the permission problem for the default socket creation at
>>> /var/run/dovecot/stats-writer rather than working round it.
>>>
>>> John
>>>
>> Just following up, I don't get the error when I run preauth as root with
>> -u parameter. I do get something similar when I run as the user (this
>> wil the socket path set to blank)
>>
>> Centos 7:
>>
>> Error: net_connect_unix() failed: Connection refused
>>
>> FreeBSD 11.2:
>>
>> Error: net_connect_unix() failed: No such file or directory
>>
>> So it's close. If I get time I'll see if I can track it down.
>
> Does this fix it?
>
> diff --git a/src/lib-master/master-service.c
> b/src/lib-master/master-service.c
> index 3de11fa1b..3c60a7a39 100644
> --- a/src/lib-master/master-service.c
> +++ b/src/lib-master/master-service.c
> @@ -341,7 +341,7 @@ master_service_init(const char *name, enum
> master_service_flags flags,
>         if ((flags & MASTER_SERVICE_FLAG_DONT_SEND_STATS) == 0) {
>                 /* Initialize stats-client early so it can see all
> events. */
>                 value = getenv(DOVECOT_STATS_WRITER_SOCKET_PATH);
> -               if (value != NULL)
> +               if (value != NULL && *value != '\0')
>                         service->stats_client =
> stats_client_init(value, FALSE);
>         }
>
>
> Regards,
>
> Stephan.
>
Hi Stephan

that fixes the issue that I reproduced. For the OP he will probably need
to wait for this to be picked up for FreeBSD ports.

This code seems safer than the original but it is still a mystery as to
why DOVECOT_STATS_WRITER_SOCKET_PATH is being put into the environment
as an empty string (changed behaviour reported by OP compared to 2.3.2.1_1).

The function that is doing the env_put call with the empty string is
config_request_putenv from src/config/doveconf.c.

John