topic perl daemon script in Operating System - HP-UX

perl daemon script

Inesa Clinko — Tue, 28 Jul 2009 13:48:05 GMT

Plese help me with Perl daemon script.
When I'm executing the main script, it created child process,but don't want to exit itself. :(
I have to press enter, in oder to stop the main script. I want to use this script in
/sbin/init.d, so I want the main script to exit itself, and the child process to remain as daemon, doing some job...
Here is the script bellow:

#!/usr/bin/perl -w

use POSIX;
use Getopt::Std;
use English;
use strict;

use constant FALSE => 0;
use constant TRUE => 1;

# ****** Main Program

my $kontinue = TRUE;

sub close_n_exit
{
$kontinue = FALSE;
return(15);
} # close_n_exit

my $cc = 0;
my $pid = fork();
if ($pid == 0)
{ # child - daemonize the process

POSIX::setsid() or die "Can't start a new session: $!";
$SIG{HUP} = 'IGNORE';
# $SIG{QUIT} = 'IGNORE';
$SIG{INT} = 'IGNORE';
$SIG{PIPE} = 'IGNORE';
$SIG{TERM} = \&close_n_exit;
while ($kontinue)
{
print `date`;
sleep(10);
}
}
else
{ # parent process - just exit; the child is doing the real work
exit($cc);
}
exit($cc);

Please help me to make the right script.
It will be points, of course :)

Re: perl daemon script

James R. Ferguson — Tue, 28 Jul 2009 14:42:26 GMT

Hi:

Run this version. Notice that the child process directs its STDOUT to a file (which you can view with 'tail -f' as the daemon runs on).

Your code is decidedly C-like. A much more Perl-ish version is this:

#!/usr/bin/perl
use POSIX qw( setsid );
use strict;
use warnings;
my $logfile = '/var/tmp/mydaemon';
my $pid;
sub close_n_exit {
print STDERR "going away...\n";
exit 1;
} # close_n_exit
chdir '/' or die "Can't cd to /: $!\n";
open( STDIN , '<', '/dev/null' ) or die "Can't open /dev/null: $!\n";
open( STDOUT, '>', $logfile ) or die "Can't open '$logfile': $!\n";
$|++; #...set autoflush on STDOUT...
defined($pid = fork) or die "Can't fork(): $!\n";
exit if $pid;
setsid or die "Can't start a new session: $!";
$SIG{HUP} = 'IGNORE';
$SIG{QUIT} = 'IGNORE';
$SIG{INT} = 'IGNORE';
$SIG{PIPE} = 'IGNORE';
$SIG{TERM} = \&close_n_exit;
while (1) {
print STDOUT scalar localtime, "\n";
sleep 10;
}
exit 0

Regards!

...JRF...

Re: perl daemon script

Inesa Clinko — Wed, 29 Jul 2009 05:36:01 GMT

Thanks ,James