Provided by: crashme_2.8.5-1build1_amd64 
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)