#!/usr/bin/perl

use strict;
use warnings;

my %gettys;
my $have_cad = 0;


#-----------------------------------------------------------------------------#
# Parse /etc/inittab
#-----------------------------------------------------------------------------#

open INITTAB, "/etc/inittab"
or die "Unable to open /etc/inittab: $!";

while (<INITTAB>) {
chomp;
s/^\s*//;

next if /^\#/;
next unless length;

my ($id, $rlevel, $action, $process) = split /:/, $_, 4;

warn "missing id field" and next
unless defined $id and length $id;
warn "missing runlevel field" and next
unless defined $rlevel;
warn "missing action field" and next
unless defined $action and length $action;
warn "missing process field" and next
unless defined $process;


$have_cad = 1 if $action eq "ctrlaltdel";
$gettys{$1} = [ $rlevel, $process ] if $process =~ /getty.*\b(tty\w+)/;
}

close INITTAB
or warn "Error while closing /etc/inittab: $!";


#-----------------------------------------------------------------------------#
# Alter /etc/event.d
#-----------------------------------------------------------------------------#

unlink "/etc/init/control-alt-delete.conf"
unless $have_cad;

foreach (qw/tty1 tty2 tty3 tty4 tty5 tty6/) {
unlink "/etc/init/$_.conf"
unless exists $gettys{$_};
}

foreach (sort keys %gettys) {
my ($rlevel, $process) = @{$gettys{$_}};

my @job;
if (-f "/etc/event.d/$_") {
open JOB, "/etc/event.d/$_"
or warn "Unable to open /etc/event.d/$_: $!" and next;
@job = <JOB>;
chomp @job;
close JOB
or warn "Error while closing /etc/event,d/$_: $!" and next;

foreach my $rl (qw/2 3 4 5/) {
my $idx;
for ($idx = 0; $idx < @job; $idx++) {
last if $job[$idx] =~ /^\s*(start|stop)\s+on\s+runlevel\s+$rl\b/;
}

if ($idx < @job) {
if ($rlevel =~ /$rl/) {
$job[$idx] =~ s/^(\s*)stop(\s+)/$1start$2/;
} else {
$job[$idx] =~ s/^(\s*)start(\s+)/$1stop$2/;
}
} else {
if ($rlevel =~ /$rl/) {
push @job, "start on runlevel $rl";
} else {
push @job, "stop on runlevel $rl";
}
}
}

my $idx;
for ($idx = 0; $idx < @job; $idx++) {
last if $job[$idx] =~ /^\s*respawn\s*/; # match bare 'respawn' too
}

if ($idx < @job) {
# only match old-style 'respawn process', not bare 'respawn'
$job[$idx] =~ s/^(\s*respawn\s+).*/$1$process/;
} else {
push @job, "respawn";
push @job, "exec $process";
}

# Try to fix up effects of previous broken migrations
if (@job and $job[$#job] =~ /.*(.+?)exec (\1)$/) {
$job[$#job] = "exec $1";
}

} else {
push @job, "# $_ - getty";
push @job, "#";
push @job, "# Converted from /etc/inittab entry";
push @job, "";

foreach my $rl (qw/2 3 4 5/) {
if ($rlevel =~ /$rl/) {
push @job, "start on runlevel $rl";
} else {
push @job, "stop on runlevel $rl";
}
}
push @job, "";

push @job, "stop on shutdown";
push @job, "";

push @job, "respawn";
push @job, "exec $process";
}

open JOB, ">/etc/event.d/.$_"
or warn "Unable to write to /etc/event.d/.$_: $!" and next;
print JOB map { "$_\n" } @job;
unless (close JOB) {
warn "Error while closing /etc/event.d/.$_: $!";
unlink "/etc/event.d/.$_";
next;
}

unless (rename "/etc/event.d/.$_", "/etc/event.d/$_") {
warn "Unable to replace /etc/event.d/$_: $!";
unlink "/etc/event.d/.$_";
next;
}
}