root/user/testbin/forkbomb/forkbomb.c

DEFINITIONS

1. main

   1 /*
   2  * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
   3  *      The President and Fellows of Harvard College.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  30 /*
  31  * forkbomb - apply malthus to an operating system ;-)
  32  *
  33  * DO NOT RUN THIS ON A REAL SYSTEM - IT WILL GRIND TO A HALT AND
  34  * PEOPLE WILL COME AFTER YOU WIELDING BASEBALL BATS OR THE AD
  35  * BOARD(*). WE WARNED YOU.
  36  *
  37  * We don't expect your system to withstand this without grinding to
  38  * a halt, but once your basic system calls are complete it shouldn't
  39  * crash. Likewise for after your virtual memory system is complete.
  40  *
  41  * (...at least in an ideal world. However, it can be difficult to
  42  * handle all the loose ends involved. Heroic measures are not
  43  * expected. If in doubt, talk to the course staff.)
  44  *
  45  *
  46  * (*) The Administrative Board of Harvard College handles formal
  47  * disciplinary action.
  48  */
  50 #include <unistd.h>
  51 #include <err.h>
  53 static volatile int pid;
  55 int
main()
  57 {
  58         int i;
  60         while (1) {
fork();
pid = getpid();
  65                 /* Make sure each fork has its own address space. */
  66                 for (i=0; i<300; i++) {
  67                         volatile int seenpid;
seenpid = pid;
  69                         if (seenpid != getpid()) {
errx(1, "pid mismatch (%d, should be %d) "
  71                                      "- your vm is broken!", 
seenpid, getpid());
  73                         }
  74                 }
  75         }
  76 }