| #!/usr/bin/perl | 
 | use strict; | 
 |  | 
 | # Copyright (c) 2017 Mauro Carvalho Chehab <mchehab@kernel.org> | 
 | # | 
 | # This program is free software; you can redistribute it and/or | 
 | # modify it under the terms of the GNU General Public License | 
 | # as published by the Free Software Foundation; either version 2 | 
 | # of the License, or (at your option) any later version. | 
 | # | 
 | # This program is distributed in the hope that it will be useful, | 
 | # but WITHOUT ANY WARRANTY; without even the implied warranty of | 
 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the | 
 | # GNU General Public License for more details. | 
 |  | 
 | my $virtenv_dir = "sphinx_1.4"; | 
 | my $requirement_file = "Documentation/sphinx/requirements.txt"; | 
 |  | 
 | # | 
 | # Static vars | 
 | # | 
 |  | 
 | my %missing; | 
 | my $system_release; | 
 | my $need = 0; | 
 | my $optional = 0; | 
 | my $need_symlink = 0; | 
 | my $need_sphinx = 0; | 
 | my $install = ""; | 
 |  | 
 | # | 
 | # Command line arguments | 
 | # | 
 |  | 
 | my $pdf = 1; | 
 | my $virtualenv = 1; | 
 |  | 
 | # | 
 | # List of required texlive packages on Fedora and OpenSuse | 
 | # | 
 |  | 
 | my %texlive = ( | 
 | 	'amsfonts.sty'       => 'texlive-amsfonts', | 
 | 	'amsmath.sty'        => 'texlive-amsmath', | 
 | 	'amssymb.sty'        => 'texlive-amsfonts', | 
 | 	'amsthm.sty'         => 'texlive-amscls', | 
 | 	'anyfontsize.sty'    => 'texlive-anyfontsize', | 
 | 	'atbegshi.sty'       => 'texlive-oberdiek', | 
 | 	'bm.sty'             => 'texlive-tools', | 
 | 	'capt-of.sty'        => 'texlive-capt-of', | 
 | 	'cmap.sty'           => 'texlive-cmap', | 
 | 	'ecrm1000.tfm'       => 'texlive-ec', | 
 | 	'eqparbox.sty'       => 'texlive-eqparbox', | 
 | 	'eu1enc.def'         => 'texlive-euenc', | 
 | 	'fancybox.sty'       => 'texlive-fancybox', | 
 | 	'fancyvrb.sty'       => 'texlive-fancyvrb', | 
 | 	'float.sty'          => 'texlive-float', | 
 | 	'fncychap.sty'       => 'texlive-fncychap', | 
 | 	'footnote.sty'       => 'texlive-mdwtools', | 
 | 	'framed.sty'         => 'texlive-framed', | 
 | 	'luatex85.sty'       => 'texlive-luatex85', | 
 | 	'multirow.sty'       => 'texlive-multirow', | 
 | 	'needspace.sty'      => 'texlive-needspace', | 
 | 	'palatino.sty'       => 'texlive-psnfss', | 
 | 	'parskip.sty'        => 'texlive-parskip', | 
 | 	'polyglossia.sty'    => 'texlive-polyglossia', | 
 | 	'tabulary.sty'       => 'texlive-tabulary', | 
 | 	'threeparttable.sty' => 'texlive-threeparttable', | 
 | 	'titlesec.sty'       => 'texlive-titlesec', | 
 | 	'ucs.sty'            => 'texlive-ucs', | 
 | 	'upquote.sty'        => 'texlive-upquote', | 
 | 	'wrapfig.sty'        => 'texlive-wrapfig', | 
 | ); | 
 |  | 
 | # | 
 | # Subroutines that checks if a feature exists | 
 | # | 
 |  | 
 | sub check_missing(%) | 
 | { | 
 | 	my %map = %{$_[0]}; | 
 |  | 
 | 	foreach my $prog (sort keys %missing) { | 
 | 		my $is_optional = $missing{$prog}; | 
 |  | 
 | 		if ($is_optional) { | 
 | 			print "Warning: better to also install \"$prog\".\n"; | 
 | 		} else { | 
 | 			print "ERROR: please install \"$prog\", otherwise, build won't work.\n"; | 
 | 		} | 
 | 		if (defined($map{$prog})) { | 
 | 			$install .= " " . $map{$prog}; | 
 | 		} else { | 
 | 			$install .= " " . $prog; | 
 | 		} | 
 | 	} | 
 |  | 
 | 	$install =~ s/^\s//; | 
 | } | 
 |  | 
 | sub add_package($$) | 
 | { | 
 | 	my $package = shift; | 
 | 	my $is_optional = shift; | 
 |  | 
 | 	$missing{$package} = $is_optional; | 
 | 	if ($is_optional) { | 
 | 		$optional++; | 
 | 	} else { | 
 | 		$need++; | 
 | 	} | 
 | } | 
 |  | 
 | sub check_missing_file($$$) | 
 | { | 
 | 	my $file = shift; | 
 | 	my $package = shift; | 
 | 	my $is_optional = shift; | 
 |  | 
 | 	return if(-e $file); | 
 |  | 
 | 	add_package($package, $is_optional); | 
 | } | 
 |  | 
 | sub findprog($) | 
 | { | 
 | 	foreach(split(/:/, $ENV{PATH})) { | 
 | 		return "$_/$_[0]" if(-x "$_/$_[0]"); | 
 | 	} | 
 | } | 
 |  | 
 | sub check_program($$) | 
 | { | 
 | 	my $prog = shift; | 
 | 	my $is_optional = shift; | 
 |  | 
 | 	return if findprog($prog); | 
 |  | 
 | 	add_package($prog, $is_optional); | 
 | } | 
 |  | 
 | sub check_perl_module($$) | 
 | { | 
 | 	my $prog = shift; | 
 | 	my $is_optional = shift; | 
 |  | 
 | 	my $err = system("perl -M$prog -e 1 2>/dev/null /dev/null"); | 
 | 	return if ($err == 0); | 
 |  | 
 | 	add_package($prog, $is_optional); | 
 | } | 
 |  | 
 | sub check_python_module($$) | 
 | { | 
 | 	my $prog = shift; | 
 | 	my $is_optional = shift; | 
 |  | 
 | 	my $err = system("python3 -c 'import $prog' 2>/dev/null /dev/null"); | 
 | 	return if ($err == 0); | 
 | 	my $err = system("python -c 'import $prog' 2>/dev/null /dev/null"); | 
 | 	return if ($err == 0); | 
 |  | 
 | 	add_package($prog, $is_optional); | 
 | } | 
 |  | 
 | sub check_rpm_missing($$) | 
 | { | 
 | 	my @pkgs = @{$_[0]}; | 
 | 	my $is_optional = $_[1]; | 
 |  | 
 | 	foreach my $prog(@pkgs) { | 
 | 		my $err = system("rpm -q '$prog' 2>/dev/null >/dev/null"); | 
 | 		add_package($prog, $is_optional) if ($err); | 
 | 	} | 
 | } | 
 |  | 
 | sub check_pacman_missing($$) | 
 | { | 
 | 	my @pkgs = @{$_[0]}; | 
 | 	my $is_optional = $_[1]; | 
 |  | 
 | 	foreach my $prog(@pkgs) { | 
 | 		my $err = system("pacman -Q '$prog' 2>/dev/null >/dev/null"); | 
 | 		add_package($prog, $is_optional) if ($err); | 
 | 	} | 
 | } | 
 |  | 
 | sub check_missing_tex($) | 
 | { | 
 | 	my $is_optional = shift; | 
 | 	my $kpsewhich = findprog("kpsewhich"); | 
 |  | 
 | 	foreach my $prog(keys %texlive) { | 
 | 		my $package = $texlive{$prog}; | 
 | 		if (!$kpsewhich) { | 
 | 			add_package($package, $is_optional); | 
 | 			next; | 
 | 		} | 
 | 		my $file = qx($kpsewhich $prog); | 
 | 		add_package($package, $is_optional) if ($file =~ /^\s*$/); | 
 | 	} | 
 | } | 
 |  | 
 | sub check_sphinx() | 
 | { | 
 | 	return if findprog("sphinx-build"); | 
 |  | 
 | 	if (findprog("sphinx-build-3")) { | 
 | 		$need_symlink = 1; | 
 | 		return; | 
 | 	} | 
 |  | 
 | 	if ($virtualenv) { | 
 | 		my $prog = findprog("virtualenv-3"); | 
 | 		$prog = findprog("virtualenv-3.5") if (!$prog); | 
 |  | 
 | 		check_program("virtualenv", 0) if (!$prog); | 
 | 		$need_sphinx = 1; | 
 | 	} else { | 
 | 		add_package("python-sphinx", 0); | 
 | 	} | 
 | } | 
 |  | 
 | # | 
 | # Ancillary subroutines | 
 | # | 
 |  | 
 | sub catcheck($) | 
 | { | 
 |   my $res = ""; | 
 |   $res = qx(cat $_[0]) if (-r $_[0]); | 
 |   return $res; | 
 | } | 
 |  | 
 | sub which($) | 
 | { | 
 | 	my $file = shift; | 
 | 	my @path = split ":", $ENV{PATH}; | 
 |  | 
 | 	foreach my $dir(@path) { | 
 | 		my $name = $dir.'/'.$file; | 
 | 		return $name if (-x $name ); | 
 | 	} | 
 | 	return undef; | 
 | } | 
 |  | 
 | # | 
 | # Subroutines that check distro-specific hints | 
 | # | 
 |  | 
 | sub give_debian_hints() | 
 | { | 
 | 	my %map = ( | 
 | 		"python-sphinx"		=> "python3-sphinx", | 
 | 		"sphinx_rtd_theme"	=> "python3-sphinx-rtd-theme", | 
 | 		"virtualenv"		=> "virtualenv", | 
 | 		"dot"			=> "graphviz", | 
 | 		"convert"		=> "imagemagick", | 
 | 		"Pod::Usage"		=> "perl-modules", | 
 | 		"xelatex"		=> "texlive-xetex", | 
 | 		"rsvg-convert"		=> "librsvg2-bin", | 
 | 	); | 
 |  | 
 | 	if ($pdf) { | 
 | 		check_missing_file("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", | 
 | 				   "fonts-dejavu", 1); | 
 | 	} | 
 |  | 
 | 	check_program("dvipng", 1) if ($pdf); | 
 | 	check_missing(\%map); | 
 |  | 
 | 	return if (!$need && !$optional); | 
 | 	printf("You should run:\n\n\tsudo apt-get install $install\n"); | 
 | } | 
 |  | 
 | sub give_redhat_hints() | 
 | { | 
 | 	my %map = ( | 
 | 		"python-sphinx"		=> "python3-sphinx", | 
 | 		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme", | 
 | 		"virtualenv"		=> "python3-virtualenv", | 
 | 		"dot"			=> "graphviz", | 
 | 		"convert"		=> "ImageMagick", | 
 | 		"Pod::Usage"		=> "perl-Pod-Usage", | 
 | 		"xelatex"		=> "texlive-xetex-bin", | 
 | 		"rsvg-convert"		=> "librsvg2-tools", | 
 | 	); | 
 |  | 
 | 	my @fedora26_opt_pkgs = ( | 
 | 		"graphviz-gd",		# Fedora 26: needed for PDF support | 
 | 	); | 
 |  | 
 | 	my @fedora_tex_pkgs = ( | 
 | 		"texlive-collection-fontsrecommended", | 
 | 		"texlive-collection-latex", | 
 | 		"dejavu-sans-fonts", | 
 | 		"dejavu-serif-fonts", | 
 | 		"dejavu-sans-mono-fonts", | 
 | 	); | 
 |  | 
 | 	# | 
 | 	# Checks valid for RHEL/CentOS version 7.x. | 
 | 	# | 
 | 	if (!($system_release =~ /Fedora/)) { | 
 | 		$map{"virtualenv"} = "python-virtualenv"; | 
 | 	} | 
 |  | 
 | 	my $release; | 
 |  | 
 | 	$release = $1 if ($system_release =~ /Fedora\s+release\s+(\d+)/); | 
 |  | 
 | 	check_rpm_missing(\@fedora26_opt_pkgs, 1) if ($pdf && $release >= 26); | 
 | 	check_rpm_missing(\@fedora_tex_pkgs, 1) if ($pdf); | 
 | 	check_missing_tex(1) if ($pdf); | 
 | 	check_missing(\%map); | 
 |  | 
 | 	return if (!$need && !$optional); | 
 |  | 
 | 	if ($release >= 18) { | 
 | 		# dnf, for Fedora 18+ | 
 | 		printf("You should run:\n\n\tsudo dnf install -y $install\n"); | 
 | 	} else { | 
 | 		# yum, for RHEL (and clones) or Fedora version < 18 | 
 | 		printf("You should run:\n\n\tsudo yum install -y $install\n"); | 
 | 	} | 
 | } | 
 |  | 
 | sub give_opensuse_hints() | 
 | { | 
 | 	my %map = ( | 
 | 		"python-sphinx"		=> "python3-sphinx", | 
 | 		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme", | 
 | 		"virtualenv"		=> "python3-virtualenv", | 
 | 		"dot"			=> "graphviz", | 
 | 		"convert"		=> "ImageMagick", | 
 | 		"Pod::Usage"		=> "perl-Pod-Usage", | 
 | 		"xelatex"		=> "texlive-xetex-bin", | 
 | 		"rsvg-convert"		=> "rsvg-view", | 
 | 	); | 
 |  | 
 | 	my @suse_tex_pkgs = ( | 
 | 		"texlive-babel-english", | 
 | 		"texlive-caption", | 
 | 		"texlive-colortbl", | 
 | 		"texlive-courier", | 
 | 		"texlive-dvips", | 
 | 		"texlive-helvetic", | 
 | 		"texlive-makeindex", | 
 | 		"texlive-metafont", | 
 | 		"texlive-metapost", | 
 | 		"texlive-palatino", | 
 | 		"texlive-preview", | 
 | 		"texlive-times", | 
 | 		"texlive-zapfchan", | 
 | 		"texlive-zapfding", | 
 | 	); | 
 |  | 
 | 	check_rpm_missing(\@suse_tex_pkgs, 1) if ($pdf); | 
 | 	check_missing_tex(1) if ($pdf); | 
 | 	check_missing(\%map); | 
 |  | 
 | 	return if (!$need && !$optional); | 
 | 	printf("You should run:\n\n\tsudo zypper install --no-recommends $install\n"); | 
 | } | 
 |  | 
 | sub give_mageia_hints() | 
 | { | 
 | 	my %map = ( | 
 | 		"python-sphinx"		=> "python3-sphinx", | 
 | 		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme", | 
 | 		"virtualenv"		=> "python3-virtualenv", | 
 | 		"dot"			=> "graphviz", | 
 | 		"convert"		=> "ImageMagick", | 
 | 		"Pod::Usage"		=> "perl-Pod-Usage", | 
 | 		"xelatex"		=> "texlive", | 
 | 		"rsvg-convert"		=> "librsvg2-tools", | 
 | 	); | 
 |  | 
 | 	my @tex_pkgs = ( | 
 | 		"texlive-fontsextra", | 
 | 	); | 
 |  | 
 | 	check_rpm_missing(\@tex_pkgs, 1) if ($pdf); | 
 | 	check_missing(\%map); | 
 |  | 
 | 	return if (!$need && !$optional); | 
 | 	printf("You should run:\n\n\tsudo urpmi $install\n"); | 
 | } | 
 |  | 
 | sub give_arch_linux_hints() | 
 | { | 
 | 	my %map = ( | 
 | 		"sphinx_rtd_theme"	=> "python-sphinx_rtd_theme", | 
 | 		"virtualenv"		=> "python-virtualenv", | 
 | 		"dot"			=> "graphviz", | 
 | 		"convert"		=> "imagemagick", | 
 | 		"xelatex"		=> "texlive-bin", | 
 | 		"rsvg-convert"		=> "extra/librsvg", | 
 | 	); | 
 |  | 
 | 	my @archlinux_tex_pkgs = ( | 
 | 		"texlive-core", | 
 | 		"texlive-latexextra", | 
 | 		"ttf-dejavu", | 
 | 	); | 
 | 	check_pacman_missing(\@archlinux_tex_pkgs, 1) if ($pdf); | 
 | 	check_missing(\%map); | 
 |  | 
 | 	return if (!$need && !$optional); | 
 | 	printf("You should run:\n\n\tsudo pacman -S $install\n"); | 
 | } | 
 |  | 
 | sub give_gentoo_hints() | 
 | { | 
 | 	my %map = ( | 
 | 		"sphinx_rtd_theme"	=> "dev-python/sphinx_rtd_theme", | 
 | 		"virtualenv"		=> "dev-python/virtualenv", | 
 | 		"dot"			=> "media-gfx/graphviz", | 
 | 		"convert"		=> "media-gfx/imagemagick", | 
 | 		"xelatex"		=> "dev-texlive/texlive-xetex media-fonts/dejavu", | 
 | 		"rsvg-convert"		=> "gnome-base/librsvg", | 
 | 	); | 
 |  | 
 | 	check_missing_file("/usr/share/fonts/dejavu/DejaVuSans.ttf", | 
 | 			   "media-fonts/dejavu", 1) if ($pdf); | 
 |  | 
 | 	check_missing(\%map); | 
 |  | 
 | 	return if (!$need && !$optional); | 
 |  | 
 | 	printf("You should run:\n\n"); | 
 | 	printf("\tsudo su -c 'echo \"media-gfx/imagemagick svg png\" > /etc/portage/package.use/imagemagick'\n"); | 
 | 	printf("\tsudo su -c 'echo \"media-gfx/graphviz cairo pdf\" > /etc/portage/package.use/graphviz'\n"); | 
 | 	printf("\tsudo emerge --ask $install\n"); | 
 |  | 
 | } | 
 |  | 
 | sub check_distros() | 
 | { | 
 | 	# Distro-specific hints | 
 | 	if ($system_release =~ /Red Hat Enterprise Linux/) { | 
 | 		give_redhat_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /CentOS/) { | 
 | 		give_redhat_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /Scientific Linux/) { | 
 | 		give_redhat_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /Oracle Linux Server/) { | 
 | 		give_redhat_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /Fedora/) { | 
 | 		give_redhat_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /Ubuntu/) { | 
 | 		give_debian_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /Debian/) { | 
 | 		give_debian_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /openSUSE/) { | 
 | 		give_opensuse_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /Mageia/) { | 
 | 		give_mageia_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /Arch Linux/) { | 
 | 		give_arch_linux_hints; | 
 | 		return; | 
 | 	} | 
 | 	if ($system_release =~ /Gentoo/) { | 
 | 		give_gentoo_hints; | 
 | 		return; | 
 | 	} | 
 |  | 
 | 	# | 
 | 	# Fall-back to generic hint code for other distros | 
 | 	# That's far from ideal, specially for LaTeX dependencies. | 
 | 	# | 
 | 	my %map = ( | 
 | 		"sphinx-build" => "sphinx" | 
 | 	); | 
 | 	check_missing_tex(1) if ($pdf); | 
 | 	check_missing(\%map); | 
 | 	print "I don't know distro $system_release.\n"; | 
 | 	print "So, I can't provide you a hint with the install procedure.\n"; | 
 | 	print "There are likely missing dependencies.\n"; | 
 | } | 
 |  | 
 | # | 
 | # Common dependencies | 
 | # | 
 |  | 
 | sub check_needs() | 
 | { | 
 | 	if ($system_release) { | 
 | 		print "Detected OS: $system_release.\n"; | 
 | 	} else { | 
 | 		print "Unknown OS\n"; | 
 | 	} | 
 |  | 
 | 	# RHEL 7.x and clones have Sphinx version 1.1.x and incomplete texlive | 
 | 	if (($system_release =~ /Red Hat Enterprise Linux/) || | 
 | 	    ($system_release =~ /CentOS/) || | 
 | 	    ($system_release =~ /Scientific Linux/) || | 
 | 	    ($system_release =~ /Oracle Linux Server/)) { | 
 | 		$virtualenv = 1; | 
 | 		$pdf = 0; | 
 |  | 
 | 		printf("NOTE: On this distro, Sphinx and TexLive shipped versions are incompatible\n"); | 
 | 		printf("with doc build. So, use Sphinx via a Python virtual environment.\n\n"); | 
 | 		printf("This script can't install a TexLive version that would provide PDF.\n"); | 
 | 	} | 
 |  | 
 | 	# Check for needed programs/tools | 
 | 	check_sphinx(); | 
 | 	check_perl_module("Pod::Usage", 0); | 
 | 	check_program("make", 0); | 
 | 	check_program("gcc", 0); | 
 | 	check_python_module("sphinx_rtd_theme", 1) if (!$virtualenv); | 
 | 	check_program("xelatex", 1) if ($pdf); | 
 | 	check_program("dot", 1); | 
 | 	check_program("convert", 1); | 
 | 	check_program("rsvg-convert", 1) if ($pdf); | 
 |  | 
 | 	check_distros(); | 
 |  | 
 | 	if ($need_symlink) { | 
 | 		printf "\tsudo ln -sf %s /usr/bin/sphinx-build\n\n", | 
 | 		       which("sphinx-build-3"); | 
 | 	} | 
 | 	if ($need_sphinx) { | 
 | 		my $activate = "$virtenv_dir/bin/activate"; | 
 | 		if (-e "$ENV{'PWD'}/$activate") { | 
 | 			printf "\nNeed to activate virtualenv with:\n"; | 
 | 			printf "\t. $activate\n"; | 
 | 		} else { | 
 | 			my $virtualenv = findprog("virtualenv-3"); | 
 | 			$virtualenv = findprog("virtualenv-3.5") if (!$virtualenv); | 
 | 			$virtualenv = findprog("virtualenv") if (!$virtualenv); | 
 | 			$virtualenv = "virtualenv" if (!$virtualenv); | 
 |  | 
 | 			printf "\t$virtualenv $virtenv_dir\n"; | 
 | 			printf "\t. $activate\n"; | 
 | 			printf "\tpip install -r $requirement_file\n"; | 
 | 			$need++; | 
 | 		} | 
 | 	} | 
 | 	printf "\n"; | 
 |  | 
 | 	print "All optional dependenties are met.\n" if (!$optional); | 
 |  | 
 | 	if ($need == 1) { | 
 | 		die "Can't build as $need mandatory dependency is missing"; | 
 | 	} elsif ($need) { | 
 | 		die "Can't build as $need mandatory dependencies are missing"; | 
 | 	} | 
 |  | 
 | 	print "Needed package dependencies are met.\n"; | 
 | } | 
 |  | 
 | # | 
 | # Main | 
 | # | 
 |  | 
 | while (@ARGV) { | 
 | 	my $arg = shift(@ARGV); | 
 |  | 
 | 	if ($arg eq "--no-virtualenv") { | 
 | 		$virtualenv = 0; | 
 | 	} elsif ($arg eq "--no-pdf"){ | 
 | 		$pdf = 0; | 
 | 	} else { | 
 | 		print "Usage:\n\t$0 <--no-virtualenv> <--no-pdf>\n\n"; | 
 | 		exit -1; | 
 | 	} | 
 | } | 
 |  | 
 | # | 
 | # Determine the system type. There's no standard unique way that would | 
 | # work with all distros with a minimal package install. So, several | 
 | # methods are used here. | 
 | # | 
 | # By default, it will use lsb_release function. If not available, it will | 
 | # fail back to reading the known different places where the distro name | 
 | # is stored | 
 | # | 
 |  | 
 | $system_release = qx(lsb_release -d) if which("lsb_release"); | 
 | $system_release =~ s/Description:\s*// if ($system_release); | 
 | $system_release = catcheck("/etc/system-release") if !$system_release; | 
 | $system_release = catcheck("/etc/redhat-release") if !$system_release; | 
 | $system_release = catcheck("/etc/lsb-release") if !$system_release; | 
 | $system_release = catcheck("/etc/gentoo-release") if !$system_release; | 
 | $system_release = catcheck("/etc/issue") if !$system_release; | 
 | $system_release =~ s/\s+$//; | 
 |  | 
 | check_needs; |