[Dovecot] dovecot 2.0b3 crash with lmtp and DNS based proxy

[Oliver Eales]

Timo Sirainen schrieb:
> On Fri, 2010-02-26 at 17:32 +0100, Oliver Eales wrote:
>   
>> Hello,
>> i am trying to proxy a LMTP connection with version 2.0b3
>> Currently i have the problem when trying to use a named based proxy for
>> LMTP the process doesn't resolve the hostname and crashes:
>>     
>
> Fixed crash and added DNS support:
>
> http://hg.dovecot.org/dovecot-2.0/rev/bd28e6f29711
> http://hg.dovecot.org/dovecot-2.0/rev/cc3f6adc1e0b
>   
Thank you Timo, it is working now.
But unfortunately i ran into a second problem which was already existent
before the DNS fix.
When the LMTP client sends the terminating dot to the LMTP proxy, the
proxy stalls for about 30sec at an epoll_wait() syscall.
It reads the "250 2.0.0 xxxxx" response from the backend server and then
waits.
When the epoll_wait timeout is reached, the proxy sends the "250 2.0.0
xxxxx" backend response to the client and the communication goes on
normally. (QUIT from the client or new MAIL..)
Attached is a strace excerpt of the LMTP proxy.

read(11, "sdf\r\n", 4017)               = 5
write(15, "sdf", 3)                     = 3
read(11, 0x631454, 4012)                = -1 EAGAIN (Resource
temporarily unavailable)
read(11, 0x631454, 4012)                = -1 EAGAIN (Resource
temporarily unavailable)
read(11, 0x631454, 4012)                = -1 EAGAIN (Resource
temporarily unavailable)
epoll_wait(10, {{EPOLLIN, {u32=6396992, u64=6396992}}}, 8, 60000) = 1
read(11, ".\r\n", 4012)                 = 3
write(15, "\r\n", 2)                    = 2
write(15, ".\r\n", 3)                   = 3
epoll_ctl(10, EPOLL_CTL_DEL, 11, {0, {u32=6396992, u64=6396992}}) = 0
epoll_wait(10, {{EPOLLIN, {u32=6506320, u64=6506320}}}, 8, 30000) = 1
read(15, "250 2.0.0 <vodafonemail56 at vodafo"..., 860) = 69
read(15, 0x634859, 791)                 = -1 EAGAIN (Resource
temporarily unavailable)
epoll_wait(10,{}, 8, 29992)            = 0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Here it hangs for 29992 msec.

epoll_wait(10, {}, 8, 2)                = 0
epoll_ctl(10, EPOLL_CTL_DEL, 15, {0, {u32=6506320, u64=6506320}}) = 0
close(15)                               = 0
setsockopt(11, SOL_TCP, TCP_CORK, [1], 4) = 0
write(11, "250 2.0.0 <vodafonemail56 at vodafo"..., 69) = 69
setsockopt(11, SOL_TCP, TCP_CORK, [0], 4) = 0
epoll_ctl(10, EPOLL_CTL_ADD, 11, {EPOLLIN|EPOLLPRI|EPOLLERR|EPOLLHUP,
{u32=6396992, u64=6396992}}) = 0
brk(0x657000)                           = 0x657000

Thank you and regards,
Oliver Eales