pve-guest-common/PVE/GuestHelpers.pm

package PVE::GuestHelpers;

use strict;
use warnings;

use PVE::Tools;
use PVE::Storage;

use POSIX qw(strftime);
use Scalar::Util qw(weaken);

use base qw(Exporter);

our @EXPORT_OK = qw(safe_string_ne safe_boolean_ne safe_num_ne typesafe_ne);

# We use a separate lock to block migration while a replication job
# is running.

our $lockdir = '/var/lock/pve-manager';

# safe variable comparison functions

sub safe_num_ne {
    my ($a, $b) = @_;

    return 0 if !defined($a) && !defined($b);
    return 1 if !defined($a);
    return 1 if !defined($b);

    return $a != $b;
}

sub safe_string_ne  {
    my ($a, $b) = @_;

    return 0 if !defined($a) && !defined($b);
    return 1 if !defined($a);
    return 1 if !defined($b);

    return $a ne $b;
}

sub safe_boolean_ne {
    my ($a, $b) = @_;

    # we don't check if value is defined, since undefined
    # is false (so it's a valid boolean)

    # negate both values to normalize and compare
    return !$a != !$b;
}

sub typesafe_ne {
    my ($a, $b, $type) = @_;

    return 0 if !defined($a) && !defined($b);
    return 1 if !defined($a);
    return 1 if !defined($b);

    if ($type eq 'string') {
	return safe_string_ne($a, $b);
    } elsif ($type eq 'number' || $type eq 'integer') {
	return safe_num_ne($a, $b);
    } elsif ($type eq 'boolean') {
	return safe_boolean_ne($a, $b);
    }

    die "internal error: can't compare $a and $b with type $type";
}


sub guest_migration_lock {
    my ($vmid, $timeout, $func, @param) = @_;

    my $lockid = "pve-migrate-$vmid";

    mkdir $lockdir;

    my $res = PVE::Tools::lock_file("$lockdir/$lockid", $timeout, $func, @param);
    die $@ if $@;

    return $res;
}

sub check_hookscript {
    my ($volid, $storecfg) = @_;

    $storecfg = PVE::Storage::config() if !defined($storecfg);
    my ($path, undef, $type) = PVE::Storage::path($storecfg, $volid);

    die "'$volid' is not in the snippets directory\n"
	if $type ne 'snippets';

    die "script '$volid' does not exist\n"
	if ! -f $path;

    die "script '$volid' is not executable\n"
	if ! -x $path;

    return $path;
}

sub exec_hookscript {
    my ($conf, $vmid, $phase, $stop_on_error) = @_;

    return if !$conf->{hookscript};

    eval {
	my $hookscript = check_hookscript($conf->{hookscript});
	die $@ if $@;

	PVE::Tools::run_command([$hookscript, $vmid, $phase]);
    };
    if (my $err = $@) {
	my $errmsg = "hookscript error for $vmid on $phase: $err\n";
	die $errmsg if ($stop_on_error);
	warn $errmsg;
    }
}

# takes a snapshot list (e.g., qm/pct snapshot_list API call result) and
# prints it out in a nice tree sorted by age. Can cope with multiple roots
sub print_snapshot_tree {
    my ($snapshot_list) = @_;

    my $snapshots = { map { $_->{name} => $_ } @$snapshot_list };

    my @roots;
    foreach my $e (@$snapshot_list) {
	my $parent;
	if (($parent = $e->{parent}) && defined $snapshots->{$parent}) {
	    push @{$snapshots->{$parent}->{children}}, $e->{name};
	} else {
	    push @roots, $e->{name};
	}
    }

    # sort the elements by snaptime - with "current" (no snaptime) highest
    my $snaptimesort = sub {
	return +1 if !defined $snapshots->{$a}->{snaptime};
	return -1 if !defined $snapshots->{$b}->{snaptime};
	return $snapshots->{$a}->{snaptime} <=> $snapshots->{$b}->{snaptime};
    };

    # recursion function for displaying the tree
    my $snapshottree_weak;
    $snapshottree_weak = sub {
	my ($prefix, $root, $snapshots) = @_;
	my $e = $snapshots->{$root};

	my $description = $e->{description} || 'no-description';
	($description) = $description =~ m/(.*)$/m;

	my $timestring = "";
	if (defined $e->{snaptime}) {
	    $timestring = strftime("%F %H:%M:%S", localtime($e->{snaptime}));
	}

	my $len = 30 - length($prefix); # for aligning the description
	printf("%s %-${len}s %-23s %s\n", $prefix, $root, $timestring, $description);

	if ($e->{children}) {
	    $prefix = "    $prefix";
	    foreach my $child (sort $snaptimesort @{$e->{children}}) {
		$snapshottree_weak->($prefix, $child, $snapshots);
	    }
	}
    };
    my $snapshottree = $snapshottree_weak;
    weaken($snapshottree_weak);

    foreach my $root (sort $snaptimesort @roots) {
	$snapshottree->('`->', $root, $snapshots);
    }
}

sub format_pending {
    my ($data) = @_;
    foreach my $item (sort { $a->{key} cmp $b->{key}} @$data) {
	my $k = $item->{key};
	next if $k eq 'digest';
	my $v = $item->{value};
	my $p = $item->{pending};
	if ($k eq 'description') {
	    $v = PVE::Tools::encode_text($v) if defined($v);
	    $p = PVE::Tools::encode_text($p) if defined($p);
	}
	if (defined($v)) {
	    if ($item->{delete}) {
		print "del $k: $v\n";
	    } elsif (defined($p)) {
		print "cur $k: $v\n";
		print "new $k: $p\n";
	    } else {
		print "cur $k: $v\n";
	    }
	} elsif (defined($p)) {
	    print "new $k: $p\n";
	}
    }
}

# returns the config as an array of hashes, each hash can have the following keys:
# key (the config property name, non-optional)
# value (the current value in effect - if any)
# pending (a new, still pending, value - if any)
# delete (when deletions are pending, this is set to either 2 (force) or 1 (graceful))
sub config_with_pending_array {
    my ($conf, $pending_delete_hash) = @_;

    my $res = [];

    foreach my $opt (keys %$conf) {
	next if ref($conf->{$opt});
	my $item = { key => $opt };
	$item->{value} = $conf->{$opt} if defined($conf->{$opt});
	$item->{pending} = $conf->{pending}->{$opt} if defined($conf->{pending}->{$opt});
	$item->{delete} = ($pending_delete_hash->{$opt}->{force} ? 2 : 1) if exists $pending_delete_hash->{$opt};

	push @$res, $item;
    }

    foreach my $opt (keys %{$conf->{pending}}) {
	next if $opt eq 'delete';
	next if ref($conf->{pending}->{$opt}); # just to be sure
	next if defined($conf->{$opt});
	my $item = { key => $opt };
	$item->{pending} = $conf->{pending}->{$opt};

	push @$res, $item;
    }

    while (my ($opt, $force) = each %$pending_delete_hash) {
	next if defined($conf->{pending}->{$opt});
	next if defined($conf->{$opt});
	my $item = { key => $opt, delete => ($force ? 2 : 1)};
	push @$res, $item;
    }

    return $res;
}

1;