Hi,
I'm implementing a system call, and I want to return
information (text data) to the user without using the
/var/log/messages (using the printk function). I've
been thinking about writing in a file, but I really
don't know how to manipulate files in kernel mode. The
text could be returned to the command line as well,
but I either don't know how to do that. Does anybody
could help me how to return text (both ways would be
good) from a system call?
Thanks, and sorry for the English.
so_usp
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On Mon, Jun 21, 2004 at 05:27:02PM -0300, so usp wrote:
> Hi,
>
> I'm implementing a system call, and I want to return
> information (text data) to the user without using the
> /var/log/messages (using the printk function). I've
> been thinking about writing in a file, but I really
> don't know how to manipulate files in kernel mode. The
> text could be returned to the command line as well,
> but I either don't know how to do that. Does anybody
> could help me how to return text (both ways would be
> good) from a system call?
>
What is it you want to do exactly? What kind of text?
Consider making a device driver - a device driver
can return text to the program reading from the device.
If that doesn't fit your needs, consider creating a file
in /proc.
Helge Hafting
I'm guessing this is an exercise or something - I'm not sure exactly what
you're trying to accomplish with this - but if you created a new system
call, all you'd likely need to do is to have the caller pass in a pointer to
a buffer, as well as the buffer size, with the system call, then just copy
the data into/out of the buffer using copy_to_user and copy_from_user.
----- Original Message -----
From: "so usp" <[email protected]>
Newsgroups: fa.linux.kernel
To: <[email protected]>
Sent: Monday, June 21, 2004 2:28 PM
Subject: returning text from a system call
> Hi,
>
> I'm implementing a system call, and I want to return
> information (text data) to the user without using the
> /var/log/messages (using the printk function). I've
> been thinking about writing in a file, but I really
> don't know how to manipulate files in kernel mode. The
> text could be returned to the command line as well,
> but I either don't know how to do that. Does anybody
> could help me how to return text (both ways would be
> good) from a system call?
>
> Thanks, and sorry for the English.
> so_usp
>
> ______________________________________________________________________
>
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