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Full Discussion: Daemon...Zombie?? Please help me
Top Forums Programming Daemon...Zombie?? Please help me Post 71294 by Perderabo on Monday 9th of May 2005 09:18:53 PM
Old 05-09-2005
Please make sure that you have read our rules. And note:
(6) Do not post classroom or homework problems.

But we sometimes bend this rule when a student has done a lot of work. So I'll make a few comments based on a quick scan of your code. This line of code:
while(1) sleep(1);//run
is dangerous. Why do you have it? I would delete it. If you meant to do something like:
while (1) { List() ; sleep(1) ; }
then you have the fork() in the wrong place. You need to fork() once at the beginning of the program. At present, your program is running List() once and then falling into your infinite sleep loop. You have some re-writing to do.

wait(30);
is illegal and also dangerous. I don't even know what you want to happen there. The last thing you do in List is to ignore some signals. You should ignore signals earlier. If you put List() in a loop, you need to move the signal calls to near the beginning somewhere.

Your instructor probably told you to check if the parent pid is 1, but your instructor is wrong. That is not the definition of a daemon. As it happens, you can probably get away with test you have. But the definition of a daemon is a program with no controlling terminal. You could check that by attempting to open /dev/tty. A daemon must fail but a non-damon must succeed.
 

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LEARN ABOUT DEBIAN

lnptest

lnptest(1)						      General Commands Manual							lnptest(1)

NAME

       lnptest - LNP Client Test Application

SYNOPSIS

       lnptest

DESCRIPTION

       lnptest is an LNP Daemon test client used to test the connection between lnptest and the LNP daemon through the Ir Tower to a corresponding
       test program running in an RCX.	See the FILES section for the location of the RCX test program source code (distributed  with  this  pack-
       age).

OPTIONS

       lnptest does not support command-line options.

USAGE

       To run the test:
       - compile the lnptest.c RCX program
       - start the lnpd daemon
       - download the lnptest.lx program to the RCX
       - (at the RCX) run the program just downloaded to the RCX
       - run this lnptest program
       - inspect the output looking for lack of failure messages

FILES

       /usr/share/doc/lnpd/examples/rcx
	      In this directory is the source to the RCX-side program which is called lnptest.c but written to be compiled against BrickOS.

SEE ALSO

       lnptest2(1), lnpdll(1), lnpd(8)

       You can find additional documentation in /usr/share/doc/lnpd (on Debian GNU/Linux systems)

AUTHOR

       lnptest was written by Martin Cornelius <Martin.Cornelius@t-online.de> This man page was written by Stephen Moraco <stephen@debian.org>

								 January 23, 2005							lnptest(1)
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