Re: [ros-dev] Advice required on User-mode to Kernel mode call for syslog(2) analog in ROS

[Sven Barth]

On 06.04.2011 21:26, dmex wrote:
>   What's wrong with current method of using the
> memory mapped 'DBWIN_BUFFER'
>  file for outputting kernel messages?
>  
That I didn't know about it :P

>   Two or three different kernel implementations for the
> same thing seems a bit
>  retarded and breaks compatibility with existing applications like Dbgview.
>  
I'm just looking at the source of ReactOS from time to time when I have 
the need to check out how a certain function behaves under the hood 
(especially while I ported the Free Pascal compiler to the Native NT 
API), but I weren't yet aware how those debug outputs work.
As Minas mentioned that he'd like to add a syscall/API function 
compareable to syslog I just thought that it would be wiser (from my 
restricted point of view) to write a driver for this that would allow to 
extend the system dynamically.

Regards,
Sven

>   -----Original Message-----
>  From: ros-dev-bounces(a)reactos.org [mailto:[e-mail]] On
>  Behalf Of Sven Barth
>  Sent: Wednesday, 6 April 2011 8:54 PM
>  To: ros-dev(a)reactos.org
>  Subject: Re: [ros-dev] Advice required on User-mode to Kernel mode call for
>  syslog(2) analog in ROS
>
>  Am 06.04.2011 02:09, schrieb Minas Abrahamyan:
> >   Hi all,
> >
> >  I'm going to implement dmesg.exe, a ROS application to read dmesg/kmsg
> >  buffer (debug messages in kernel buffer), which is filled in by
> >  appropriate patch 6018
> >  (here: http://www.reactos.org/bugzilla/show_bug.cgi?id=6018 ) (BTW,
> >  it's not yet reviewed and not applied!).
> >
> >  So I'm requesting advice on:
> >  What would be the better way for user-mode code to get the contents of
> >  kmsg buffer in kernel-space (kdbg)?
> >
> >  Shortly:
> >  Linux has special system call "syslog" (man 2 syslog) FreeBSD uses its
> >  special sysctl interface to kernel along with 'kern.msgbuf' parameter.
> >
> >  My questions:
> >  Do we need special system call like Linux, or even more, the whole
> >  family of them (sysctl('*')) as in BSD?
> >  How to implement simple system call for it, now? 
>  I'm not one of the ReactOS devs and also I'm not writing much here, but what
>  about implementing a (legacy type) device driver that provides a device
>  object (e.g. \Device\kmsg) that can be read from (no writing
>  though) and some code for DeviceIOControl to clear/config the buffer?
>
>  Regards,
>  Sven
>
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