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Date: -- (:)
From: Basile STARYNKEVITCH <basile@s...>
Subject: Re: [Caml-list] uname for Ocaml

Issac cited me after his reply - I put it in the right order.

>>>>> "Issac" == Issac Trotts <ijtrotts@ucdavis.edu> writes:



    Issac> On Tue, Jan 21, 2003 at 04:23:03PM +0100, Basile
    Issac> STARYNKEVITCH wrote:
    >> Dear All,
    >> 
    >> If you need to call uname(2) from some Ocaml program you can
    >> steal my tiny code in util.ml util.mli util_ml.c on
    >> 
    >> http://www2.poesia-filter.org:8000/cgi-bin/cvsweb.cgi/PoesiaSoft/PoesiaMonIcap/
    >> 
    >> I actually wish that uname(2) will be incorporated in the Unix
    >> module.
    >> 


    Issac> An alternative would be to use #load "unix.cma"

I agree with Issac, but I still wish that most (or perhaps all) of the
standard Posix system calls should be callable from Unix module!

    Issac>   let uname() = let (inc, outc) = Unix.open_process "uname"
    Issac> in let name = input_line inc in close_in inc; close_out
    Issac> outc; name;;

Won't work if the (malicious) user have an unrelated uname in his
path. I suggest at least using the "/bin/uname" which should be a
POSIX standard IIRC. Also, forking a shell process for each system
call might be not optimal (and not robust).

Also, my code return the equivalent of /bin/uname -a

    Issac> Here's a more general way to capture the stdout of a Unix
    Issac> call:

    Issac>   let syscall cmd = let (inc, outc) = Unix.open_process cmd
    Issac> in let buf = Buffer.create 16 in (try while true do
    Issac> Buffer.add_channel buf inc 1 done with _ -> ()); close_in
    Issac> inc; close_out outc; Buffer.contents buf;;

Thanks for this suggestion, but why not use Unix.open_process_in in
this and similar cases?

On a related, but independent, issue, Linux hackers might be
interested in the procfs.ml[i] files from

http://www2.poesia-filter.org:8000/cgi-bin/cvsweb.cgi/PoesiaSoft/PoesiaMonIcap/

The idea is to get the status of a process by parsing /proc/#/stat
into an intelligible structure. This is Linux specific (works on linux
2.4 & 2.5 kernels). The code is mostly a huge (and boring) scanf,
using a format stolen from the linux kernel (see comments in
procfs.ml).

Regards.


-- 

Basile STARYNKEVITCH         http://starynkevitch.net/Basile/ 
email: basile<at>starynkevitch<dot>net 
alias: basile<at>tunes<dot>org 
8, rue de la Faïencerie, 92340 Bourg La Reine, France
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