Re: adding a system call

Doug McNaught (doug@wireboard.com)
09 Jan 2001 14:17:26 -0500


Mihai Moise <mcartoaj@mat.ulaval.ca> writes:

> My system call idea is to allow a superuser process to request a mmap on
> behalf of an user process. To see how this would be useful, let us consider
> svgalib.

[...]

> With my new system call, a superuser process can set the graphics mode in a
> safe manner and then ask for an mmap of the video array into the application
> data segment.

Ummm, couldn't the the root process open the video device, then pass
the file descriptor (via AF_UNIX socket) to the user process? The
user process would then call mmap() on the open file descriptor.

I'm not *completely* sure this would work, but it would avoid creating
a new system call if so.

-Doug
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