Re: max arguments for exec

Re: max arguments for exec

[Carl Spalletta]

On Wed, 26 Sep 2001, Kiril Vidimce wrote:
 
> Yeah, I know, but we would like to avoid building a
custom kernel. If
> we do end up going this route, I wonder if there is
a limit for
> MAX_ARG_PAGES. Any idea? I think 128 pages (512K)
would be sufficient
> for our needs.

kiril, 

I am guessing that you want to avoid a custom kernel
in order that your programs shall be portable.

So, I am having a hard time understanding why putting
the command line args into a file instead of on the
command line, in a way similar to grep and many other
programs:
 
"fgrep -F patternfile"

would not answer the case.

Is there any absolute need to have so many args passed
to exec from the command line?


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Re: max arguments for exec

[Kiril Vidimce]

On Thu, 27 Sep 2001, Carl Spalletta wrote:
> kiril, 
> 
> I am guessing that you want to avoid a custom kernel
> in order that your programs shall be portable.
> 
> So, I am having a hard time understanding why putting
> the command line args into a file instead of on the
> command line, in a way similar to grep and many other
> programs:
>  
> "fgrep -F patternfile"
> 
> would not answer the case.
> 
> Is there any absolute need to have so many args passed
> to exec from the command line?

We are using third party software over which we have no 
control. So, it's not up to us.

KV
--
  ___________________________________________________________________
  Studio Tools                                        vkire@pixar.com
  Pixar Animation Studios                        http://www.pixar.com/

max arguments for exec

[Kiril Vidimce]

Is there any way to reconfigure the kernel at runtime to change the
limit for arguments passed during an exec? I guess I am looking for
something similar to systune ncargs under IRIX. I found this thread
in the archives:

http://uwsg.iu.edu/hypermail/linux/kernel/0003.0/0160.html

The only suggestion was to patch and recompile the kernel. I looked
into sysctl and I couldn't find an appropriate argument to tweak.

Thanks for any info,
KV
--
  ___________________________________________________________________
  Studio Tools                                        vkire@pixar.com
  Pixar Animation Studios                        http://www.pixar.com/

Re: max arguments for exec

[Keith Owens]

On Wed, 26 Sep 2001 14:25:05 -0700 (PDT), 
Kiril Vidimce <vkire@pixar.com> wrote:
>Is there any way to reconfigure the kernel at runtime to change the
>limit for arguments passed during an exec? I guess I am looking for
>something similar to systune ncargs under IRIX. I found this thread
>in the archives:
>
>http://uwsg.iu.edu/hypermail/linux/kernel/0003.0/0160.html
>
>The only suggestion was to patch and recompile the kernel. I looked
>into sysctl and I couldn't find an appropriate argument to tweak.

It is controlled by MAX_ARG_PAGES in include/linux/binfmts.h.  Change
and recompile the kernel, it is not dynamically tunable in Linux.

Re: max arguments for exec

[Kiril Vidimce]

On Thu, 27 Sep 2001, Keith Owens wrote:
> On Wed, 26 Sep 2001 14:25:05 -0700 (PDT), 
> Kiril Vidimce <vkire@pixar.com> wrote:
> >Is there any way to reconfigure the kernel at runtime to change the
> >limit for arguments passed during an exec? I guess I am looking for
> >something similar to systune ncargs under IRIX. I found this thread
> >in the archives:
> >
> >http://uwsg.iu.edu/hypermail/linux/kernel/0003.0/0160.html
> >
> >The only suggestion was to patch and recompile the kernel. I looked
> >into sysctl and I couldn't find an appropriate argument to tweak.
> 
> It is controlled by MAX_ARG_PAGES in include/linux/binfmts.h.  Change
> and recompile the kernel, it is not dynamically tunable in Linux.

Yeah, I know, but we would like to avoid building a custom kernel.
If we do end up going this route, I wonder if there is a limit for 
MAX_ARG_PAGES. Any idea? I think 128 pages (512K) would be sufficient 
for our needs.

KV
--
  ___________________________________________________________________
  Studio Tools                                        vkire@pixar.com
  Pixar Animation Studios                        http://www.pixar.com/

Re: max arguments for exec

[Ingo Molnar]

On Wed, 26 Sep 2001, Kiril Vidimce wrote:

> Yeah, I know, but we would like to avoid building a custom kernel. If
> we do end up going this route, I wonder if there is a limit for
> MAX_ARG_PAGES. Any idea? I think 128 pages (512K) would be sufficient
> for our needs.

be careful with MAX_ARG_PAGES, because struct binprm is allocated on the
kernel stack, so if it's too big, the kernel stack will overflow in
unexpected places. A realistic limit is 1-2 MB, that causes a 1-2 KB
kernel stack footprint.

(ob'plug: or use the patch i posted, the size of struct binprm is constant
and small there :-)

	Ingo