#!/usr/bin/perl

BEGIN {
    $etc= '/etc/backup';
    require "$etc/settings.pl";
    require 'backuplib.pl';
}

$|=1;

print "Configuration check ...\n" or die $!;
system 'checkallused'; $? and die $?;

printdate();

unlink 'TAPEID';
system "mt -f $tape rewind"; $? and die $?;
system "mt -f $tape setblk $blocksizebytes"; $? and die $?;
system "dd if=$tape bs=${blocksize}b count=10 | tar -b$blocksize -vvxf - TAPEID";

setstatus "FAILED during startup";

if (open T, "TAPEID") {
    unlink 'really-TAPEID';
} elsif (open T, "really-TAPEID") {
} else {
    die "No TAPEID.\n";
}

chomp($tapeid= <T>);
$tapeid =~ m/[^0-9a-zA-Z]/ and die "Bad TAPEID ($&).\n";
$tapeid =~ m/[0-9a-zA-Z]/ or die "Empty TAPEID.\n";
close T;

setstatus "FAILED at tape identity check";

if (open L, "last-tape") {
    chomp($lasttape= <L>);
    close L;
} else {
    undef $lasttape;
}

die "Tape $tapeid same as last time.\n" if $tapeid eq $lasttape;

if (defined($tapedesc= readlink "$etc/tape.$tapeid")) {
    $tapedesc =~ s/^.*\.//;
    $tapedesc .= "($tapeid)";
} else {
    $tapedesc = $tapeid;
}

undef $fsys;
open D, "$etc/tape.$tapeid" or die "Unknown tape $tapeid ($!).\n";
for (;;) {
    $_= <D> or die; chomp; s/\s+$//;
    last if m/^end$/;
    next unless m/\S/;
    next if m/^\#/;
    if (m/^filesystems (\w+)$/) {
	$fsys= $1;
    } elsif (m/^next (\w+)$/) {
	$next= $1;
    } elsif (m/^incremental$/) {
	$incremental= 1;
    } else {
	die "unknown entry in tape $tapeid at line $.: $_\n";
    }
}
close D or die $!;

if ($incremental) {
    die "incremental tape $tapeid has next or filesystems\n"
	if defined($next) || defined($fsys);
    print STDERR "Incremental tape $tapeid.\n\n";
    setstatus "FAILED during incremental startup";
    exec "increm",$tapeid,$tapedesc;
    die $!;
}

readfsys("$fsys");
openlog();

$doing= "dump of $fsys to tape $tapedesc in drive $tape";
print LOG "$doing:\n" or die $!;

open T, ">TAPEID" or die $!;
print T "$tapeid\n$tapedesc\n" or die $!;
close T or die $!;

system "tar -b$blocksize -vvcf TAPEID.tar TAPEID"; $? and die $?;
system "dd if=TAPEID.tar of=$ntape bs=${blocksize}b count=10"; $? and die $?;

unlink 'this-md5sums';

print "Doing $doing ...\n" or die $!;

unlink 'p';
system 'mknod p p'; $? and die $?;

setstatus "FAILED during dump";

sub closepipes () {
    close(DUMPOR); close(TEEOR); close(BUFOR); close(FINDOR);
    close(DUMPOW); close(TEEOW); close(BUFOW); close(FINDOW);
}

for $tf (@fsys) {
    printdate();
    pipe(FINDOR,FINDOW) or die $!;
    pipe(DUMPOR,DUMPOW) or die $!;
    pipe(TEEOR,TEEOW) or die $!;
    pipe(BUFOR,BUFOW) or die $!;
    parsefsys();
    if ($tm eq 'dump') {
	$dumpcmd= "dump 0bfu $softblocksizekb - $atf";
	$dumpin= '</dev/null';
    } else {
	startprocess '</dev/null','>&FINDOW',$rstr."find $atf -xdev -noleaf -print0";
	$dumpcmd= "cpio -Hustar -o0C$softblocksizebytes";
	$dumpin= '<&FINDOR';
    }
    startprocess '<p','>>this-md5sums','md5sum';
    startprocess $dumpin,'>&DUMPOW',$rstr.$dumpcmd;
    startprocess '<&DUMPOR','>&TEEOW','tee p';
    startprocess '<&TEEOR','>&BUFOW','writebuffer';
    startprocess '<&BUFOR','>/dev/null'
	,"dd ibs=$softblocksizebytes obs=$blocksizebytes of=$ntape";
    closepipes();
    endprocesses();
}

setstatus "FAILED during check";

system "mt -f $tape rewind"; $? and die $?;
system "mt -f $ntape fsf 1"; $? and die $?;

open S,"this-md5sums" or die $!;
for $tf (@fsys) {
    printdate();
    chomp($orgsum= <S>);
    $orgsum =~ m/^[0-9a-fA-F]{32}$/i or die "orgsum \`$orgsum' ?";
    chomp($csum= `readbuffer <$ntape | md5sum`);
    $orgsum eq $csum or die "MISMATCH $tf $csum $orgsum\n";
    print "checksum ok $csum\t$tf\n" or die $!;
    print LOG "checksum ok $csum\t$tf\n" or die $!;
}
printdate();
system "mt -f $tape rewind"; $? and die $?;

setstatus "FAILED during cleanup";

open IAN,">increm-advance.new" or die $!;
print IAN "1\n" or die $!;
close IAN or die $!;

open TN,">next-full.new" or die $!;
print TN "$next\n" or die $!;
close TN or die $!;

unlink 'last-tape','next-full';
rename 'TAPEID','last-tape' or die $!;
rename 'this-md5sums',"md5sums.$fsys" or die $!;
rename 'log',"log.$fsys" or die $!;
rename 'next-full.new',"next-full" or die $!;
rename 'increm-advance.new',"increm-advance" or die $!;

print "$doing completed.\nNext dump tape is $next.\n" or die $!;

setstatus "Successful: $tapedesc $fsys, next $next";
exit 0;