Date: Tue, 8 Apr 1997 17:53:26 +0000 From: "Jesus A. Mora Marin" <amora@zoom.es> To: questions@freebsd.org Subject: Becoming a daemon the long way... Message-ID: <199704081559.RAA02758@silvester.zoom.es>
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Greetings!
These days I have been discussing with a fellow about the right way
to make a process to run as a daemon. The easy way to do this seems
to be -in a simplified scheme-:
main()
{
...
if(fork()) /* let's say it'll never fail! */
exit(0); /* Parent dies */
/* child is inherited by init and becomes a daemon */
here_the_daemonized_code;
}
Another approach I saw somewhere -and the one I've been using- is a
bit more complex:
main()
{
...
if(!fork()) { /* child */
if(!fork()) { /* child's child */
while(getppid() != 1) sleep(1);
code_to_daemonize;
...
}
exit(0);
}
wait(); /* parent waits to reap the first child */
exit(0);
}
This approach seems to be aimed to guarantee that the daemon process
is inherited by init, so there is no chance to become a zombie
process if it eventually dies. Is this really needed? By the way,
are there any system related conditions that make zombies to be
generated?
TIA
----
Jesus A. Mora Marin, MD (aka EA7HAC, ex-EC7DVE)
Email: amora@zoom.es
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