Added a couple functions: afs_vname, afs_partinfo

[moira.git] / incremental / afs_utils.pl

$afsbin="/moira/bin";
$vos="$afsbin/vos";
$pts="$afsbin/pts";
$fs="$afsbin/fs";

$afs_data="/moira/afs/afs_data";
$afs_save="$afs_data.tmp";

$LOCK_EX=2;
$LOCK_UN=8;

%vtypes_ATHENA_MIT_EDU =
    ("ACTIVITY", "activity",
     "APROJ", "aproj",
     "AREF", "aref",
     "CONTRIB", "contrib",
     "COURSE", "course",
     "HOMEDIR", "user",
     "PROJECT", "project",
     "REF", "ref",
     "SW", "sw",
     "SYSTEM", "system",
     "UROP", "urop",
     );

# Function: afs_vname
# Returns the canonical volume name for (locker,type,cell)
sub afs_vname
{
    local($name,$type,$cell) = @_;

    $vtype = eval "\$vtypes_$cell{$type}";
    return "" unless $vtype;

    $vname = $vtype . "." . $name;
    $vname =~ s/[^-A-Za-z0-9_.]//g;		# strip out illegal characters
    return $vname;
}


# File format:
#    cell server partition total used alloc

# Locking/re-write algorithm:
# 1. Open the data file.
# 2. Obtain a lock on the data file.
# 3. Check for the existence of a temporary data file - die if it exists.
# 4. Save current contents into temporary data file.
# 5. Re-write output (with line-buffering).
# 6. Unlink temporary file.
# 7. Unlock data file.
# 8. Close the data file.


sub afs_lock
{
    open(SRV,"+<$afs_data") || die "Unable to open $afs_data\n";
    select((select(SRV), $|=1)[$[]);
    flock(SRV, $LOCK_EX) || die "Unable to lock $afs_data\n";
    die "Temporary status file: $afs_save exists... aborting\n"
	if (-f $afs_save);
    open(SRV2, ">$afs_save");
    @afs_data = <SRV>;
    print SRV2 @afs_data;
    close(SRV2);
    seek(SRV, 0, 0);
}

sub afs_unlock
{
    unlink($afs_save);
    close(SRV);
}

# Function: afs_find
# Finds server/partition for allocation.
#
# Best fit algorithm used:
#    max[ (2*free space) - (unused quota) ]
#    = max(2*total - usage - alloc)
#
# Note: This routine does not actually adjust the quota; the caller
# should use afs_quota_adj();
sub afs_find
{
    local($cell,$type,$quota) = @_;
    local($i, $j, $vos, $a);
    local(@max) = '';

    &afs_lock;
    chop(@afs_data);

    for $i ($[ .. $#afs_data) {
	($a, $asrv, $apart, $t, $total, $used, $alloc) =
	    split(/\s+/, $afs_data[$i]);
	next if ($a ne $cell || !$total || $type !~ /$t/);
	$alloc = $used if ($alloc < $used);
	$j = 2*$total - $used - $alloc;
	if (! @max || $j > $max[2]) {
	    ($total, $used) = &afs_partinfo($asrv, $apart, $cell);
	    next if ($?);
	    $afs_data[$i]=join(' ',$cell,$asrv,$apart,$t,$total,$used,$alloc);
	    @max = ($asrv,$apart,$j);
	}
    }

    &afs_unlock;
    return(@max);
}


# Function: afs_quota_adj
# Adjusts the quota allocation for a given server/partition
sub afs_quota_adj
{
    local($cell,$asrv,$apart,$adj) = @_;
    local($found) = 0;

    &afs_lock;
    chop(@afs_data);
    truncate(SRV, 0);
    for (@afs_data) {
	local ($c, $as, $ap, $t, $total, $used, $alloc) = split(/\s+/,$_);
	if ($c eq $cell && $as eq $asrv && $ap eq $apart) {
	    $alloc += $adj;
	    $_ = join(' ',$c,$asrv,$apart,$t,$total,$used,$alloc);
	    $found = 1;
	}
	print SRV "$_\n";
    }
    &afs_unlock;
    return($found);
}


sub afs_partinfo
{
    local($as, $ap, $c) = @_;
    local(@vos, $total, $used);

    open(VOS,"$vos partinfo $as $ap -cell $c -noauth|");
    chop(@vos = <VOS>);
    close(VOS);
    return "" if ($?);

    @vos = split(/\s+/,$vos[0]);
    $total = pop(@vos);
    $used = $total-$vos[5];
    return ($total,$used);
}