#!/usr/local/cpanel/3rdparty/bin/perl

# cpanel - scripts/patchfdsetsize                  Copyright 2022 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 Cpanel::FileUtils::TouchFile ();
use Getopt::Long;
use Pod::Usage;

my $force   = 0;
my $help    = 0;
my $default = 0;

GetOptions( 'help' => \$help, 'force' => \$force, 'default' => \$default );

pod2usage(1) if $help;

my @fd_setsize_files = qw(/usr/include/linux/posix_types.h /usr/include/bits/types.h /usr/include/bits/typesizes.h /usr/include/sys/select.h);

my $fd_setsize_skip_file = '/var/cpanel/disable_patchfdsetsize';

if ( -e $fd_setsize_skip_file ) {
    if ($force) {
        unlink $fd_setsize_skip_file;
    }
    elsif ($default) {
        print qq{FD_SETSIZE has already been reset to default value.\n};
        print qq{Use "$0 --default --force" to force reverification.\n};
        exit 0;
    }
    else {
        print "FD_SETSIZE will not be changed because ${fd_setsize_skip_file} exists.\n";
        print qq{Use "$0 --force" to remove this file and update anyway.\n};
        exit 0;
    }
}

Cpanel::FileUtils::TouchFile::touchfile($fd_setsize_skip_file) if $default;

my $target_fd_setsize = $default ? 1024  : 16384;
my $bad_fd_setsize    = $default ? 16384 : 1024;

foreach my $header_file (@fd_setsize_files) {
    next unless ( -e $header_file );
    if ( open my $header_fh, '<', $header_file ) {
        my @contents          = ();
        my $has_bad_fdsetsize = 0;

        while ( my $line = readline($header_fh) ) {
            if ( $line =~ s/(\s*\#define\s+_*FD_SETSIZE\s+)${bad_fd_setsize}/$1${target_fd_setsize}/ ) {
                $has_bad_fdsetsize = 1;
            }
            push @contents, $line;
        }
        close $header_fh;
        next unless $has_bad_fdsetsize;
        if ( open $header_fh, '>', $header_file ) {
            print $header_fh @contents;
            close $header_fh;
            print "Updated FD_SETSIZE in $header_file to $target_fd_setsize\n";
        }
        else {
            print "Couldn't open $header_file for writing: $!\n";
        }
    }
    else {
        print "Couldn't open $header_file for reading: $!\n";
    }
}

exit 0;

__END__

=head1 NAME

patchfdsetsize - Update FD_SETSIZE definitions in system header files to 16384

=head1 SYNOPSIS

patchfdsetsize [options]

    Options:
      --help       Brief help message
      --force      Rerun configuration routines when /var/cpanel/disable_patchfdsetsize exists
      --default    Switch back to default FD_SETSIZE value of 1024

=cut