#!/usr/bin/perl
#============================================================= -*-perl-*-
#
# BackupPC_nightly: Nightly cleanup & statistics script.
#
# DESCRIPTION
#
#   BackupPC_nightly performs several administrative tasks:
#
#      - monthly aging of per-PC log files (only with -m option)
#
#      - pruning files from pool no longer used (ie: those with only one
#        hard link).
#
#      - sending email to users and administrators (only with -m option)
#
#   Usage: BackupPC_nightly [-m] poolRangeStart poolRangeEnd
#
#   Flags:
#
#     -m   Do monthly aging of per-PC log files and sending of email.
#          Otherise, BackupPC_nightly just does pool pruning.
#          Since several BackupPC_nightly processes might run
#          concurrently, just the first one is given the -m flag
#          by BackupPC.
#
#   The poolRangeStart and poolRangeEnd arguments are integers from 0 to 255.
#   These specify which parts of the pool to process.  There are 256 2nd-level
#   directories in the pool (0/0, 0/1, ..., f/e, f/f).  BackupPC_nightly
#   processes the given subset of this list (0 means 0/0, 255 means f/f).
#   Therefore, arguments of 0 255 process the entire pool, 0 127 does
#   the first half (ie: 0/0 through 7/f), 127 255 does the other half
#   (eg: 8/0 through f/f) and 0 15 does just the first 1/16 of the pool
#   (ie: 0/0 through 0/f).
#
# AUTHOR
#   Craig Barratt  <cbarratt@users.sourceforge.net>
#
# COPYRIGHT
#   Copyright (C) 2001-2017  Craig Barratt
#
#   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 2 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, write to the Free Software
#   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
#========================================================================
#
# Version 3.3.2, released 25 Jan 2017.
#
# See http://backuppc.sourceforge.net.
#
#========================================================================

use strict;
no  utf8;
use lib "/usr/local/lib";
use BackupPC::Lib qw( :BPC_DT_ALL );
use BackupPC::FileZIO;
use Getopt::Std;

use File::Path;
use Data::Dumper;

die("BackupPC::Lib->new failed\n") if ( !(my $bpc = BackupPC::Lib->new) );
my $TopDir = $bpc->TopDir();
my $BinDir = $bpc->BinDir();
my %Conf   = $bpc->Conf();
my(%Status, %Info, %Jobs, @BgQueue, @UserQueue, @CmdQueue);

#
# We delete unused pool files (link count 1) in sorted inode
# order by gathering batches.  We delete the first half of
# each batch (ie: $PendingDeleteMax / 2 at a time).
#
my @PendingDelete;
my $PendingDeleteMax = 10240;

$bpc->ChildInit();

my %opts;
if ( !getopts("m", \%opts) || @ARGV != 2 ) {
    print("usage: $0 [-m] poolRangeStart poolRangeEnd\n");
    exit(1);
}
if ( $ARGV[0] !~ /^(\d+)$/ || $1 > 255 ) {
    print("$0: bad poolRangeStart '$ARGV[0]'\n");
    exit(1);
}
my $poolRangeStart = $1;
if ( $ARGV[1] !~ /^(\d+)$/ || $1 > 255 ) {
    print("$0: bad poolRangeEnd '$ARGV[1]'\n");
    exit(1);
}
my $poolRangeEnd = $1;

if ( $opts{m} ) {
    my $err = $bpc->ServerConnect($Conf{ServerHost}, $Conf{ServerPort});
    if ( $err ) {
        print("Can't connect to server ($err)\n");
        exit(1);
    }
    my $reply = $bpc->ServerMesg("status hosts");
    $reply = $1 if ( $reply =~ /(.*)/s );
    eval($reply);
}

###########################################################################
# Get statistics on the pool, and remove files that have only one link.
###########################################################################

my $fileCnt;       # total number of files
my $dirCnt;        # total number of directories
my $blkCnt;        # total block size of files
my $fileCntRm;     # total number of removed files
my $blkCntRm;      # total block size of removed files
my $blkCnt2;       # total block size of files with just 2 links
                   # (ie: files that only occur once among all backups)
my $fileCntRep;    # total number of file names containing "_", ie: files
                   # that have repeated md5 checksums
my $fileRepMax;    # worse case number of files that have repeated checksums
                   # (ie: max(nnn+1) for all names xxxxxxxxxxxxxxxx_nnn)
my $fileLinkMax;   # maximum number of hardlinks on a pool file
my $fileLinkTotal; # total number of hardlinks on entire pool
my $fileCntRename; # number of renamed files (to keep file numbering
                   # contiguous)
my %FixList;       # list of paths that need to be renamed to avoid
                   # new holes
my @hexChars = qw(0 1 2 3 4 5 6 7 8 9 a b c d e f);

for my $pool ( qw(pool cpool) ) {
    for ( my $i = $poolRangeStart ; $i <= $poolRangeEnd ; $i++ ) {
        my $dir        = "$hexChars[int($i / 16)]/$hexChars[$i % 16]";
        # print("Doing $pool/$dir\n") if ( ($i % 16) == 0 );
        $fileCnt       = 0;
        $dirCnt        = 0;
        $blkCnt        = 0;
        $fileCntRm     = 0;
        $blkCntRm      = 0;
        $blkCnt2       = 0;
        $fileCntRep    = 0;
        $fileRepMax    = 0;
        $fileLinkMax   = 0;
        $fileCntRename = 0;
        %FixList       = ();
        $bpc->find({wanted => \&GetPoolStats}, "$TopDir/$pool/$dir")
					    if ( -d "$TopDir/$pool/$dir" );
        my $kb   = $blkCnt / 2;
        my $kbRm = $blkCntRm / 2;
        my $kb2  = $blkCnt2 / 2;

	#
	# Main BackupPC_nightly counts the top-level directory
	#
	$dirCnt++ if ( $opts{m} && -d "$TopDir/$pool" && $i == 0 );

	#
	# Also count the next level directories
	#
	$dirCnt++ if ( ($i % 16) == 0
		       && -d "$TopDir/$pool/$hexChars[int($i / 16)]" );

        #
        # We need to process all pending deletes before we do the
        # renames
        #
        if ( @PendingDelete ) {
            sleep(1);
            processPendingDeletes(1);
        }

        #
        # Now make sure that files with repeated checksums are still
        # sequentially numbered
        #
        foreach my $name ( sort(keys(%FixList)) ) {
            my $rmCnt = $FixList{$name} + 1;
            my $new = -1;
            for ( my $old = -1 ; ; $old++ ) {
                my $oldName = $name;
                $oldName .= "_$old" if ( $old >= 0 );
                if ( !-f $oldName ) {
                    #
                    # We know we are done when we have missed at least
                    # the number of files that were removed from this
                    # base name, plus a couple just to be sure
                    #
                    last if ( $rmCnt-- <= 0 );
                    next;
                }
                my $newName = $name;
                $newName .= "_$new" if ( $new >= 0 );
                $new++;
                next if ( $oldName eq $newName );
                rename($oldName, $newName);
                $fileCntRename++;
            }
        }
        print("BackupPC_stats $i = $pool,$fileCnt,$dirCnt,$kb,$kb2,$kbRm,"
                              . "$fileCntRm,$fileCntRep,$fileRepMax,"
                              . "$fileCntRename,$fileLinkMax,$fileLinkTotal\n");
    }
}

sleep(1);
processPendingDeletes(1);

###########################################################################
# Tell BackupPC that it is now ok to start running BackupPC_dump
# commands.  We are guaranteed that no BackupPC_link commands will
# run since only a single CmdQueue command runs at a time, and
# that means we are safe.  As of 3.x this is irrelevant since
# BackupPC_dump runs independent of BackupPC_dump.
###########################################################################
printf("BackupPC_nightly lock_off\n");

###########################################################################
# Send email and generation of backupInfo files for each backup
###########################################################################
if ( $opts{m} ) {
    print("log BackupPC_nightly now running BackupPC_sendEmail\n");
    system("$BinDir/BackupPC_sendEmail");
    doBackupInfoUpdate();
}

#
# Update the backupInfo files based on the backups file.
# We do this just once a week (on Sun) since it is only
# needed for old backups with BackupPC <= 2.1.2.
#
sub doBackupInfoUpdate
{
    my($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
    return if ( $wday != 0 );

    foreach my $host ( sort(keys(%{$bpc->HostInfoRead()})) ) {
        my @Backups = $bpc->BackupInfoRead($host);

        for ( my $i = 0 ; $i < @Backups ; $i++ ) {
            #
            # BackupPC::Storage->backupInfoWrite won't overwrite
            # an existing file
            #
            BackupPC::Storage->backupInfoWrite("$TopDir/pc/$host",
                                               $Backups[$i]{num},
                                               $Backups[$i]);
        }
    }
}

sub GetPoolStats
{
    my($file, $fullPath) = @_;
    my($inode, $nlinks, $nblocks) = (lstat($file))[1, 3, 12];
 
    if ( -d _ ) {
        $dirCnt++;
        return;
    } elsif ( ! -f _ ) {
        return;
    }
    if ( $nlinks == 1 ) {
        $blkCntRm += $nblocks;
        $fileCntRm++;
        #
        # Save the files for later batch deletion.
        #
        # This is so we can remove them in inode order, and additionally
        # reduce any remaining chance of race condition of linking to
        # pool files vs removing pool files.  (Other aspects of the
        # design should eliminate race conditions.)
        #
        push(@PendingDelete, {
                    inode => $inode,
                    path  => $fullPath
                }
        );
        if ( @PendingDelete > $PendingDeleteMax ) {
            processPendingDeletes(0);
        }
        #
        # We must keep repeated files numbered sequential (ie: files
        # that have the same checksum are appended with _0, _1 etc).
        # There are two cases: we remove the base file xxxx, but xxxx_0
        # exists, or we remove any file of the form xxxx_nnn.  We remember
        # the base name and fix it up later (not in the middle of find).
        #
        $fullPath =~ s/_\d+$//;
        $FixList{$fullPath}++;
    } else {
        if ( $file =~ /_(\d+)$/ ) {
            $fileRepMax = $1 + 1 if ( $fileRepMax <= $1 );
            $fileCntRep++;
        }
        $fileCnt += 1;
        $blkCnt  += $nblocks;
        $blkCnt2 += $nblocks if ( $nlinks == 2 );
        $fileLinkMax = $nlinks if ( $fileLinkMax < $nlinks );
        $fileLinkTotal += $nlinks - 1;
    }
}

sub processPendingDeletes
{
    my($doAll) = @_;
    my @delete;

    if ( !$doAll ) {
        @delete = splice(@PendingDelete, 0, $PendingDeleteMax / 2);
    } else {
        @delete = @PendingDelete;
        @PendingDelete = ();
    }
    for my $f ( sort({ $a->{inode} <=> $b->{inode} } @delete) ) {
        my($nlinks) = (lstat($f->{path}))[3];

        next if ( $nlinks != 1 );
        # print("Deleting $f->{path} ($f->{inode})\n");
        unlink($f->{path});
    }
}
