#!/usr/bin/perl

=head1 NAME

blink - blink disks in a disk enclosure


=head1 SYNOPSIS

B<blink> [-n|--on|-f|--off|-t|--toggle] [I<device>|--all|-d|--all-detected|-s|--all-slots]

B<blink> I<action> I<what>


=head1 DESCRIPTION

B<blink> blinks a device in a harddisk enclosure.

If no I<action> is given the blinking be will toggled.

If no I<device> is given all detected disks in enclosures will be
used.

If no I<action> and no I<device> is given all detected harddisks will
be off and all empty slots or slots with non-detected harddisks in
enclosures will blink. These slots should be safe to remove.


=head1 OPTIONS

=over 9

=item I<action>

What action to do. One of B<-n>, B<--on>, B<-f>, B<--off>, B<-t>,
B<--toggle>. Default is B<--toggle>.


=item I<what>

What slots to perform the action on.  One of B<-d>, B<--all>,
B<--all-detected>, B<-s>, B<--all-slots>, I<device>. Default is
B<--all-detected>.


=item I<device>

The disk device to blink. Either as I<sdX> or as I</dev/sdX>.


=item B<--all-detected>

=item B<--all>

=item B<-d>

Select all the detected devices.


=item B<--all-slots>

=item B<-s>

Select all slots in the enclosures.


=item B<--on>

=item B<-n>

Turn the blink on.


=item B<--off>

=item B<-f>

Turn the blink off.


=item B<--toggle>

=item B<-t>

Toggle the blink.


=back

=head1 EXAMPLE: Blink harddisk /dev/sdf

To blink /dev/sdf

B<blink /dev/sdf>


=head1 EXAMPLE: Blink all undetected slots

It will be safe to remove disk from all the blinking slots as the
slots are either empty or not detected.

B<blink>


=head1 EXAMPLE: Turn off blinking of all slots

Turn off the blinking.

B<blink -s -f>


=head1 EXIT STATUS

Always returns true.


=head1 REPORTING BUGS

Contact Ole Tange <ole@tange.dk>.


=head1 AUTHOR

Copyright (C) 2012 Ole Tange <ole@tange.dk>.


=head1 LICENSE

Copyright (C) 2012 Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
at your option any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.


=head1 DEPENDENCIES

B<blink> uses Perl and GNU Parallel.


=head1 SEE ALSO

B<sg3_utils>(1), B<parallel>(1).

=cut

use Getopt::Long;

GetOptions(
    "n|on" => \$::opt_on,
    "f|off" => \$::opt_off,
    "t|toggle" => \$::opt_toggle,
    "d|all|all-detected|alldetected" => \$::opt_alldetected,
    "s|all-slots|allslots" => \$::opt_allslots,
    );

my @more_args = ();
if(@ARGV) {
    for(@ARGV) {
      s{/dev/}{}g;
      if(/^md/) {
	  # RAID device. Try to find the matching physical devices
	  my $md = $_;
	  for my $line (grep /^$md :/, `cat /proc/mdstat`) {
	      # md1 : active raid6 sdat[14](S) sdx[13] sds[12](S) sdc[6](S) sdb[0] sdm[9] sdk[7] sdaa[10] sdi[5] sdh[4] 
	      while($line =~ s/(\S+)\[//) {
		  push @more_args, $1;
	      }
	  }
      }
    }
}
push @ARGV,@more_args;


if(not ($::opt_on or $::opt_off or $::opt_toggle or 
	$::opt_alldetected or $::opt_allslots or @ARGV)) {
    # Default:
    #   Turn on all
    #   Turn off all-detected
    $locate = "/sys/class/enclosure/*/*/locate";
    on($locate);
    $locate = "/sys/class/enclosure/*/*/device/enclosure*/locate";
    off($locate);
    exit;
}

if($::opt_alldetected) {
    $locate = "/sys/class/enclosure/*/*/device/enclosure*/locate";
} elsif($::opt_allslots) {
    $locate = "/sys/class/enclosure/*/*/locate";
} else {
    if($#ARGV == 0) {
	$dev = shift;
    } else {
	local($"=",");
	$dev = @ARGV ? "{@ARGV}" : "*";
    }
    $locate = "/sys/class/enclosure/*/*/device/block/$dev/../../enclosure*/locate";
}

if($::opt_on) {
    on($locate);
} elsif($::opt_off) {
    off($locate);
} else {
    toggle($locate);
}


sub on {
    my $locate = shift;
    print(q{bash -c 'parallel -j1 echo 1 \\> {} ::: }. $locate."'\n");
    system(q{bash -c 'parallel -j1 echo 1 \\> {} ::: }. $locate."'\n");
}


sub off {
    my $locate = shift;
    print(q{bash -c 'parallel -j1 echo 0 \\> {} ::: }. $locate."'\n");
    system(q{bash -c 'parallel -j1 echo 0 \\> {} ::: }. $locate."'\n");
}


sub toggle {
    my $locate = shift;
    # If the file 'locate' contains 1 it should be put to 0.
    print(q{bash -c 'parallel -j1 grep -q 1 {} \; echo \$? \\> {} ::: }. $locate."'\n");
    system(q{bash -c 'parallel -j1 grep -q 1 {} \; echo \$? \\> {} ::: }. $locate."'\n");
}