NAME

       crashme - test operating environment software robustness

SYNOPSIS

       crashme [NBYTES] [SRAND] [NTRYS] [NSUB] [VERBOSE]

DESCRIPTION

       crashme  is  a  very  simple  program that tests the operating environment's robustness by
       invoking random data as if it were a procedure.   The  standard  signals  are  caught  and
       handled  with a setjmp back to a loop which will try again to produce a fault by executing
       random data. Some people call this stress testing.

   COMMAND LINE OPTIONS
       [NBYTES]
               The [NBYTES] should be an integer, specifying the size of the random  data  string
               in  bytes. If given negative then the bytes are printed instead of being executed.
               If given with an explicit plus sign then the storage  for  the  bytes  is  freshly
               malloc'ed  each  time.  This  can have an effect on machines with separate I and D
               cache mechanisms. The argument can also have a dot in it, X.Y, in which case Y  is
               a  increment  for  a pointer into the random data. The buffer is recalculated only
               when the pointer gets near the end of the data.

               The are two magic values for [NBYTES] : A value of 81920 avoids malloc and returns
               a  pointer  to static data. This makes the operation of crashme more repeatable on
               architectures where malloc is designed to return unpredictable locations. A  value
               of 1025 avoids a call that sets the protection of the data to READ+WRITE+EXEC.

       [SRAND] The [SRAND] is an input seed to the random number generator, passed to srand.

       [NTRIES]
               The [NTRIES] is how many times to loop before exiting normally from the program.

       [NSUB]  The  [NSUB] is optional, the number of vfork subprocesses running all at once.  If
               negative run one after another. If given as a time  hrs:mns:scs  (hours,  minutes,
               seconds) then one subprocess will be run to completion, followed by another, until
               the time limit has been reached.  If this argument is given as the empty string or
               . then it is ignored.

               When  in  sequential-subprocess  mode  there  is  a  30  second time limit on each
               subprocess. This is to allow the instruction-set-space  random  walk  to  continue
               when a process bashes itself into an infinite loop.  For example, the ntrys can be
               bashed to a very large number with nbytes bashed to  zero.  (10  second  limit  on
               Windows NT).

               The SRAND argument is incremented by one for each subprocess.

       [VERBOSE]
               The [VERBOSE] arg is optional. 0 is the least verbose, 5 the most.

   ENVIRONMENT VARIABLES
       CRASHLOG
               The  CRASHLOG is the name of the file which the parent process opens in write mode
               and all child processes open in append mode. There is  frequent  flushing  of  the
               file  but  no  locking,  so the output may be interleaved. If the operating system
               crashes then this file might provide a short-cut to a more  resent  random  number
               seed  sequence  to  allow  for quicker finding of the special case that caused the
               crash.

       CRASHPRNG
               The CRASHPRNG can be set to RAND to use the system-provided rand function,  or  MT
               to  use  the  Mersenne  twister  (default) as coded by Takuji Nishimura and Makoto
               Matsumoto, or VNSQ to use the author's  kludge  interpretation  of  Von  Neumann's
               middle-square method.

EXAMPLE

       This is a suggested test, to run it for a least an hour.

       crashme +2000 666 100 1:00:00

FILES

       crashme.c

DIAGNOSTICS

       When  a  signal  is  caught the number and nature of the signal is indicated.  Setting the
       environment variable CRASHLOG will cause each subprocess to record the  arguments  it  was
       given.

BUGS

       Not  all  signals are caught, and the state of the user program/process environment can be
       sufficiently damaged such that the program terminates before going  through  all  [NTRIES]
       operations.

       If  the  architecture  uses some kind of procedure descriptor but no special code has been
       not been added to castaway() in crashme.c then the stress test will not be as potent as it
       would otherwise be.

       Beware:  This  program can crash your computer if the operating system or hardware of same
       is buggy. User data may be lost.

AUTHOR

       George  J   Carrette.   GJC@alum.mit.edu   http://people.delphiforums.com/gjc/crashme.html
       http://crashme.codeplex.com/

VERSION

       2.8.5 6-AUG-2014

                                                                                       CRASHME(1)