From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Thu, 14 Feb 2008 17:14:33 +0000
To: "Fans of the OS Plan 9 from Bell Labs" <9fans@cse.psu.edu>
Subject: Re: [9fans] Google search of the day
From: "Eris Discordia" <eris.discordia@gmail.com>
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On Thu, 14 Feb 2008 16:45:02 -0000, Douglas A. Gwyn <DAGwyn@null.net>
wrote:

> john@csplan9.rit.edu wrote:
>>         for (;;)
>>                 fork();
>
> In genuine UNIX(tm) systems, there is a per-user process limit,
> so eventually the fork requests start failing.  However, this
> program keeps trying to fork, so if you kill off some of the
> child processes it will spawn replacements.
>

That is not limited to UNIX proper. FreeBSD (and relatives, I suppose) all
have the /etc/login.conf where one can set limits on virtually all aspects
of user priviliges (cputime, filesize, datasize, stacksize, coredumpsize,
memoryuse, maxproc, openfiles, sbsize, etc) for arbitrary user classes. I
think it will be possible to kill the spawned children, because they are
all bound to have pids larger than a certain number.

I do not know if Linux has similar facilities. As for Plan 9, the book by
Francisco Ballesteros mentions a piece of code worse than the above and
points out that the only way to get rid of it would be to reboot the
system (which is quite as funny as the "bootsplash: silent mode," by the
way).

----snippet----
/* rabbits.c */

#include <u.h>
#include <libc.h>

void
main(int, char*[])
{
	// just like rabbits...
	while(fork())
		;
	exits(nil);
}
----snippet----

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