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X-WM-Posted-At: avacado.atomice.net; Thu, 30 May 02 02:38:51 +0100
Message-ID: <00dc01c2077a$c07828e0$0100a8c0@advent02>
From: "Chris January" <chris AT atomice DOT net>
To: <cygwin-developers AT cygwin DOT com>
References: <008601c2068e$193b6200$0100a8c0 AT advent02> <20020528223943 DOT GA18086 AT redhat DOT com> <00fc01c2069a$17e09680$0100a8c0 AT advent02> <20020528235306 DOT GC18281 AT redhat DOT com>
Subject: Re: Question about process enumeration and _pinfo structure
Date: Thu, 30 May 2002 02:38:25 +0100
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> >> >I want to add a member to the _pinfo structure which contains the
command
> >> >line originally passed to the process. At the moment, when the Cygwin
DLL
> >> >needs a list of the current Cygwin processes it uses winpids to
enumerate
> >> >the processes and the _pinfo structures for each Cygwin process are
> >copied
> >> >from a named file mapping. So to store the command line I either need
to:
> >> >i) make the command line an in-line array, e.g. char cmdline[1024];
> >> >or
> >> >ii) make the member a pointer to a string allocated on the cygwin
heap.
> >>
> >> I'm not wild about either idea.  The reason there is no command line in
> >> the pinfo structure is because I didn't want to waste shared memory
space
> >> on something that was rarely used.  I also didn't want to have to
recreate
> >> the command line in dll process startup.
> >A third alternative is to get the information from the process
environment
> >block. However this is NT specific and doesn't handle fork'ed processes.
I
> >don't understand why you would need to recreate the command line in dll
> >process startup though.
>
> The command line is not always passed to the process.  It can get just an
> argv list.
>
> >So is any solution preferred or shall I just drop the idea of
> >/proc/<n>/cmdline ?
>
> How about a "get_argv" option to cygwin_internal?
>
> I'll see if I can come up with something.
While you'll looking at this, there are some other things that I need to be
able to get information about too:
i) the current directory of a process. Presently, this is stored in the
cygheap structure, which AFAIK is inaccessible outside of that process. I
have some code which uses some undocumented NT internal structures that gets
the current directory of a Win32 process, but this doesn't allow for
symlinks and virtual paths (a la /proc).
ii)  the environment of a process. This can be got with just NT internal
calls, but I'd prefer to have something that works on Win 9x too.
iii) a processes' fd table. Again, this is stored in the cygheap structure.
iv) the current root of the process (cf chroot). Again, this is stored in
the cygheap structure.

Regards
Chris