Re: [MAS-discuss] Server stability (or: how to kill MAS server in 21 microseconds:-)

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On Sat, 25 Feb 2006 16:51:14 +0100
Kyku <ky...@os...> wrote:

> Hi all,
> 
> Suppose the following scenario:
> 1) open the MAS server in one terminal
> 2) open command line client in another, connect to the server.
> 3) pressing Ctrl-C in the client.
> 
> In my case, server starts consuming 100% CPU, then prints:
> mas: PANIC: unexpected harmful signal ...

You forgot to mention what version of the server you are using (mas -v).
However, it appears that you are not using the latest version available on
the sf.net download site - mas-1.6.6t3.  When I run that version and kill
macl with a ^C (a couple times), I get, from the macl terminal (quoted):

> $ macl 10102
> Select action:
>      Select tradable (s) View data (v) Edit indicators (e)
>      Edit market analyzers (m) Run market analysis (a)
>      Set date for market analysis (d) Edit event registrants (r)
>      End client session (x) Help (h) Product information (p)
>      Show settings (w) 
> Unexpected exception occurred.
> Exiting ...
> $ 
> $ macl 10102
> Select action:
>      Select tradable (s) View data (v) Edit indicators (e)
>      Edit market analyzers (m) Run market analysis (a)
>      Set date for market analysis (d) Edit event registrants (r)
>      End client session (x) Help (h) Product information (p)
>      Show settings (w) 
> Unexpected exception occurred.
> Exiting ...
> $ macl 10102
> Select action:
>      Select tradable (s) View data (v) Edit indicators (e)
>      Edit market analyzers (m) Run market analysis (a)
>      Set date for market analysis (d) Edit event registrants (r)
>      End client session (x) Help (h) Product information (p)
>      Show settings (w) 
> Unexpected exception occurred.
> Exiting ...

and from the server terminal:

> Caught signal in main menu:
> Broken pipe (13)
> Details: Exception  occurred :
> "Broken pipe"
> Type of Exception : Operating system signal.
> 
> [Exception trace:
> -------------------------------------------------------------------------------
> Class / Object      Routine                Nature of
> exception           Effect
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation        Broken pipe:
> <B7AE3030>                                 Operating system
> signal.      Exit
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation
> <B7AE3030>                                 Routine
> failure.              Exit
> ------------------------------------------------------------------------------- ]
>  - continuing ...
> 
> Caught signal in main menu:
> Broken pipe (13)
> Details: Exception  occurred :
> "Broken pipe"
> Type of Exception : Operating system signal.
> 
> [Exception trace:
> -------------------------------------------------------------------------------
> Class / Object      Routine                Nature of
> exception           Effect
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation        Broken pipe:
> <B7AE3030>                                 Operating system
> signal.      Exit
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation
> <B7AE3030>                                 Routine
> failure.              Exit
> ------------------------------------------------------------------------------- ]
>  - continuing ...
> 
> Caught signal in main menu:
> Broken pipe (13)
> Details: Exception  occurred :
> "Broken pipe"
> Type of Exception : Operating system signal.
> 
> [Exception trace:
> -------------------------------------------------------------------------------
> Class / Object      Routine                Nature of
> exception           Effect
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation        Broken pipe:
> <B7AE3030>                                 Operating system
> signal.      Exit
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation
> <B7AE3030>                                 Routine
> failure.              Exit
> ------------------------------------------------------------------------------- ]
>  - continuing ...

As you can see, the server now continues to accept new connections after
the broken pipe signal, although the error message is rather funky.
(It would be better if the error message was less dramatic and more
indicative that an unexpected event occurred but that it is "no big
deal".)

Download mas_v1.6.6t3.gz from the download site (reachable from
eiffel-mas.sf.net) and you should find the same behavior.  (Tip: To
get the current version of a running server, connect to it with macl and
enter 'p' - e.g.:

$ macl 10102
Select action:
     Select tradable (s) View data (v) Edit indicators (e)
     Edit market analyzers (m) Run market analysis (a)
     Set date for market analysis (d) Edit event registrants (r)
     End client session (x) Help (h) Product information (p)
     Show settings (w) p

Market Analysis Server
Version: 1.6.6t3
Copyright 1998 - 2004: Jim Cochrane
Version date: July 20, 2004
Assertion checking is disabled.
Licence:

Eiffel Forum License, version 1
...)

Jim Cochrane

> 
> mas: system execution failed.
> Following is the set of recorded exceptions.
> NB: The raised panic may have induced completely inconsistent
> information:
> 
> -------------------------------------------------------------------------------
> Class / Object      Routine                Nature of
> exception Effect
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation        unexpected harmful signal:
> <08351488>                                 Eiffel run-time
> panic.        Bye
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation
> <08351488>                                 Routine
> failure.              Bye
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation
> <08351488>                                 Routine
> failure.              Bye
> -------------------------------------------------------------------------------
> MA_SERVER           root's creation
> <08351488>                                 Routine
> failure.              Bye
> -------------------------------------------------------------------------------
> 
> mas: dumping core to generate debugging information...
> fish: Job 0, 'sudo ./mas -f,
> 22917 /usr/local/stow/mas/lib/data/*.txt' terminated by signal
> SIGABRT (Abort)
> 
> Now, when the MAS is consuming 100% CPU, I can hit Ctrl-c in the
> server terminal, which starts printing:
> Caught signal in main menu:
> Broken pipe (13) - continuing ...
> 
> Could you please help me with this. Frankly, I consider it a bug - a 
> server should withstand malicious/bad input from its clients.
> 
> 
> 
> 
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