#!/usr/bin/perl
# cpanel - installd/apt-get-wait                   Copyright 2021 cPanel, L.L.C.
#                                                           All rights reserved.
# copyright@cpanel.net                                         http://cpanel.net
# This code is subject to the cPanel license. Unauthorized copying is prohibited

use strict;
use warnings;

use File::FcntlLock;

# Define our locks, assume all are locked to start
my %lock_files = (
    '/var/lib/dpkg/lock'           => 1,
    '/var/lib/dpkg/lock-frontend'  => 1,
    '/var/cache/apt/archives/lock' => 1,
    '/var/lib/apt/lists/'          => 1
);

my $args = join( " ", @ARGV );
my $cmd  = $0;
$cmd =~ s/^(?:.+\/)?(.+)\-wait$/$1/;

my $clear = 0;

until ($clear) {

    foreach my $path ( keys %lock_files ) {
        my $fs = File::FcntlLock->new();
        open my $fh, '<', $path or die "Can't open file: $!\n";

        if ( !$fs->lock( $fh, F_SETLK ) ) {
            close($fh) or die "can't close $path: $!";
            $lock_files{$path} = 1;

            # Locking failed: File or segment already locked by other process(es)
            # wait a tenth of a second and try again
            select( undef, undef, undef, .10 );
        }
        else {
            $fs->l_type(F_UNLCK);
            $fs->lock( $fh, F_SETLK ) or print "Unlocking failed: " . $fs->error . "\n";
            close($fh)                or print "can't close $path: $! !!!\n";
            $lock_files{$path} = 0;
        }
    }

    # If either path is locked, set all paths to locked and start over
    foreach my $locked ( values %lock_files ) {
        if ( $locked == 1 ) {
            foreach my $lock_file_path ( keys %lock_files ) {
                $lock_files{$lock_file_path} = 1;
            }
            $clear = 0;
            last;
        }
        else {
            $clear = 1;
        }
    }
}

exec "$cmd $args";