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Subject: Re: A UTF-8 environment specification; an alternative to assuming UTF-8 based on choice of literal encoding
From: Tom Honermann (tom_at_[hidden])
Date: 2021-07-30 11:08:29


On 7/30/21 12:02 PM, Corentin Jabot wrote:
>
>
> On Fri, Jul 30, 2021 at 5:41 PM Tom Honermann <tom_at_[hidden]
> <mailto:tom_at_[hidden]>> wrote:
>
> On 7/30/21 10:56 AM, Thiago Macieira via SG16 wrote:
> > On Thursday, 29 July 2021 19:11:03 PDT Charlie Barto wrote:
> >> If such functionality were to be added it would be neat if the
> linux
> >> implementations worked even if procfs were not mounted (such as
> when the
> >> process is init) unless I'm mistaken fetching the command line
> through proc
> >> for your own process is making like two system calls to
> de-reference a
> >> pointer into your own address space.
> > Going off-topic here, but correcting the above.
> > Procfs is not required for one's own command-line and
> environment in any Unix
> > I know of. They are duplicated in Linux's /proc, but they are
> added to the
> > process' virtual address space just above the stack (and below
> the auxv).
>
> True today, but I suspect their location is subject to change (though
> probably unlikely).
>
> Is there a straight forward way to determine their location in memory?
>
>
> Do we need to?
>
> It seems like a robust (yet painful) solution would be to ask the
> language below (c folks) to make this happen
> (When glibc calls main it can put argv in a global)

I only asked because I needed this functionality in the past (10+ years
ago) and never found a good solution for Linux.  Most of the other OSs I
needed a solution for did expose these in global variables (z/OS was
another notable exception; I never was able to get a properly delimited
argv there other than from main()).

Tom.

> Tom.
>
> >
> > Trivia: if you modify that area, the /proc files also change,
> allowing you to
> > change the name presented in ps and similar tools.
> >
> > $ ps -o pid,command -Cfile.so
> >      PID COMMAND
> >     4873 file.so [kdeinit5] file
> local:/run/user/1000/klauncherdAEtky.1.slave-
> > socket local:/run/user/1000/kded5hvkirU.1.slave-socket
> >     4874 file.so [kdeinit5] file
> local:/run/user/1000/klauncherdAEtky.1.slave-
> > socket local:/run/user/1000/kded5FwKgfB.2.slave-socket
> >
>



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