<!-- Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009, 2013 The President and Fellows of Harvard College. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. --> <html> <head> <title>malloctest</title> <body bgcolor=#ffffff> <h2 align=center>malloctest</h2> <h4 align=center>OS/161 Reference Manual</h4> <h3>Name</h3> <p> malloctest - some simple tests for userlevel malloc </p> <h3>Synopsis</h3> <p> <tt>/testbin/malloctest</tt> [<em>test</em>...] </p> <h3>Description</h3> <p> <tt>malloctest</tt> contains 7 tests, 1-7. These may be run interactively or from the command line. </p> <p> Test 1 checks if all the bytes we ask for actually get allocated. </p> <p> Test 2 checks if <tt>malloc</tt> gracefully handles failing requests. This test assumes that <tt>malloc</tt> will eventually fail if one keeps allocating enough memory, instead of promising memory it can't deliver and then (perhaps) killing processes when it runs out. More detail regarding this condition can be found in comments in the source code. </p> <p> Test 3 also checks if <tt>malloc</tt> gracefully handles failing requests, and thus has the same restrictions as test 2. </p> <p> Test 4 attempts to check if <tt>malloc</tt> coalesces the free list properly. This test is only meant for first-fit, next-fit, or best-fit allocators; anything else will most likely confuse it. Running test 4 after other tests may confuse it as well. </p> <p> Tests 5-7 are a randomized stress test. Test 5 uses pseudorandom seed 0. Test 6 seeds the random generator from the <A HREF=../dev/random.html>random:</A> device. Test 7 prompts you for a specific seed. </p> <h3>Requirements</h3> <p> <tt>malloctest</tt> uses the following system calls: <ul> <li> <A HREF=../syscall/open.html>open</A> <li> <A HREF=../syscall/read.html>read</A> <li> <A HREF=../syscall/write.html>write</A> <li> <A HREF=../syscall/close.html>close</A> <li> <A HREF=../syscall/_exit.html>_exit</A> </ul> </p> <p> Your system should pass all the <tt>malloctest</tt> tests, subject to the conditions described above, once you have implemented <A HREF=../syscalls/sbrk.html>sbrk</A>. </p> <h3>Bugs</h3> <p> Because OS/161 ships with a userlevel <tt>malloc</tt> implementation now, rather than making you write one, this test is not very useful. </p> <p> Because the userlevel <tt>malloc</tt> OS/161 ships with is quite dumb, test 3 can be amazingly slow. </p> </body> </html>