Strange behaviour with ptmx file descriptors

[Nacho del Rey]

Hi Angel and many thanks for your answer

The application still sending & receiving data
  .- strace over the application:

write(1, "\33[1;1H\237#SF                                 \234", 44) = 44
<--it was sent from the application to the terminal, but ssh didn't
received this string
read(0, "\10", 1024) = 1           <- the client remained sending data and
it was received by the application
read(0, "\n", 1024) = 1
write(1, "\33[6;6H", 6) = 6         <-- the answered '\n' but it wasn't
received by the ssh

finally, several minutes later, the operator realized the screen is frozen
and he closed the ssh client

The strange thing is all file descriptors of all processes are in place but
it seems for any strange reason, something happen to fd#13 ( C Program fd
#1 --> ssd read fd #13) because it disappears from the select call (it
won't be available in the read fd set ever)

ssh client is made by Honeywell company.

This behaviour is similar as when you send a Ctrl+S from the ssh client but
in this case, fd#13 is not lost.

Kind regards

Nacho.





2016-04-15 2:06 GMT+02:00 Ángel González <keisial at gmail.com>:

> Hello Nacho
>
> El 04/04/16 15:38, Nacho del Rey escribió:
>
>> Hi list
>>
> (…)
>
>> Transmission KO
>>
>> read(13, "\7\33[1;16H \33[6;6H_______\33[7;1H -INFORME CANT.
>> RECOGIDA-\33[7;26H", 16384) = 67
>>
>> write(3,
>>
>> "P\247\244}\277\322\260\21\3314\7\227\223~\317\360\35\334\232\372\237\250\320\312\1;\25\37\23\363\363O&0\355i{zUbr\365,\362yyl\222",
>> 48) = 48
>>
>> It seems the file descriptor disappears while the system call (read) is
>> reading from it?
>>
> No, the file descriptor will still be there.
>
> sshd is taking the program output from the terminal (13) and sending out
> through the socket
> (3). What's the corresponding strace of the client ssh?
>
>
> I ran out of ideas. Can anybody drive me to the right direction?
>>
>> Regards, Nacho.
>>
> What's the terminal emulator used in the client side? Does resetting it
> (from a menu option) make it receive the server output again?
>
>
> Cheers
>
>