System-call in Kernel Space

SandeepKsinha sandeepksinha at gmail.com
Fri Jul 19 04:03:35 EDT 2013


On Fri, Jul 19, 2013 at 1:29 PM, Saket Sinha <saket.sinha89 at gmail.com>wrote:

>   We all know that system-calls are for user-space.
> I have a file-system driver where I have to use system calls in
> kernel-space.
>
>  Normally, we DON'T do any high level IOs from Kernel space (file
> creation/reading, and so on). But here in my driver I am  stacking FS
> drivers, I can't avoid this. This is partly because Linux kernel can't
> handle FS stacking (this wouldn't be an issue for Windows, for instance,
> which supports stacking),
>
>
Provide complete context of what you are trying to do.


> The simple (and legal) way to create a dir/file whatever is to call system
> calls, like, for instance sys_mkdir. The problem is that I am not in a
> context where I can call these. Because they expect a call from user mode,
> while I am in kernel mode. This is even why I implemented macros such as:
> https://github.com/HeisSpiter/hepunion/blob/master/fs/hepunion/hepunion.h#L399.
> This one disables all checks from user mode calls, since I am in kernel.
> And this allows calling system calls.
>
>  This is not a good way so is there any alternative.
>
> Regards,
> Saket Sinha
>
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>


-- 
Regards,
Sandeep.






“To learn is to change. Education is a process that changes the learner.”
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