From: sct@dcs.ed.ac.uk (Stephen Tweedie) Subject: Re: do mmap and/or dlopen exist for linux? Date: 22 Jun 1993 02:20:29 GMT
On 19 Jun 93 16:14:54 GMT, muts@muts.hacktic.nl (Peter Mutsaers) said:
> On Thu, 17 Jun 1993 21:40:25 GMT, entropy@world.std.com (Lawrence Foard) said:
> LF> I've been playing with memory management some and have a read
> LF> only mmap call working. Basically borrowing from the code that
> LF> maps executables and libraries. If anyone wants the patchs I'll
> LF> e-mail them, however I won't make any promises about writtable
> LF> MMF's since I don't have much free time. First I'd like to unify
> LF> memory mapped files, shared libraries and executables.
It's been done - thank Eric Youngdale for that!
> In the kernel source there is a file called /usr/src/linux/mm/mmap.c
> (pl10) and in libc.a there is
> mmap.o:
> U _errno
> 00000000 T _mmap
> I didn't try them, but are they not functional then?
Nope, they're not quite. In particular, the standard mmap() only
allows you to map /dev/mem, /dev/kmem and /dev/zero. (XFree86 needs
the /dev/mem mmap() in order to map the video frame buffer into
memory.)
Eric has got a much improved mmap() going, but it's still missing a
lot; in particular, it is pretty much read-only just now. I'm working
on the rest of the mmap() semantics, and should have something
workable soon.
(For all of you waiting for a compressed filesystem, don't panic - I
haven't completely forgotten about it, honest! The new mmap is quite
important because it is intricately tied into both the memory manager
and the filesystem, and the compressed filesystem introduces technical
problems which I really need to get all sorted out before proceeding
with the compressing code.)
Cheers,
Stephen.