#!/usr/bin/perl
#
# The LearningOnline Network with CAPA
#
# $Id: distprobe,v 1.26 2021/12/21 13:57:47 raeburn Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA 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.
#
# LON-CAPA 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.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#

my $dist='default';
my $unknown;
if (-e '/etc/oracle-release') {
    open(IN,'</etc/oracle-release');
    my $versionstring=<IN>;
    chomp($versionstring);
    close(IN);
    if ($versionstring =~ /^Oracle Linux Server release (\d+)/) {
        $dist = 'oracle'.$1;
    }
} elsif (-e '/etc/redhat-release') {
    open(IN,'</etc/redhat-release');
    my $versionstring=<IN>;
    chomp($versionstring);
    close(IN);
    if ($versionstring =~ /^Red Hat Linux release ([\d\.]+) /) {
        $version = $1;
        if ($version=~/^7\./) {
            $dist='redhat7';
        } elsif ($version=~/^8\./) {
            $dist='redhat8';
        } elsif ($version=~/^9/) {
            $dist='redhat9';
        }
    } elsif ($versionstring =~ /Fedora( Core)? release ([\d\.]+) /) {
	my $version=$2;
	if ($version - int($version) > .9) {
	    $dist = 'fedora'.(int($version)+1);
	} else {
	    $dist = 'fedora'.int($version);
	}
    } elsif ($versionstring =~ /Red Hat Enterprise Linux [AE]S release ([\d\.]+) /) {
        $dist = 'rhes'.$1;
    } elsif ($versionstring =~ /Red Hat Enterprise Linux Server release (\d+)/) {
        $dist = 'rhes'.$1;
    } elsif ($versionstring =~ /Red Hat Enterprise Linux release (\d+)/) {
        $dist = 'rhes'.$1;
    } elsif ($versionstring =~ /CentOS(| Linux| Stream) release (\d+)/) {
        $dist = 'centos'.$2;
        if ($1 eq ' Stream') {
            $dist .= '-stream';
        }
    } elsif ($versionstring =~ /Scientific Linux (?:SL )?release ([\d.]+) /) {
        my $ver = $1;
        $ver =~ s/\.\d+$//;
        $dist = 'scientific'.$ver;
    } elsif ($versionstring =~ /Rocky Linux release ([\d.]+)/) {
        my $ver = $1;
        $ver =~ s/\.\d+$//;
        $dist = 'rocky'.$ver;
    } elsif ($versionstring =~ /AlmaLinux release ([\d.]+)/) {
        my $ver = $1;
        $ver =~ s/\.\d+$//;
        $dist = 'alma'.$ver;
    } else {
        warn('Unable to interpret /etc/redhat-release '.
             'to determine system type');
        $unknown = 1;
    }
} elsif (-e '/etc/SuSE-release') {
    open(IN,'</etc/SuSE-release');
    my $versionstring=<IN>;
    chomp($versionstring);
    close(IN);
    if ($versionstring =~ /^SUSE LINUX Enterprise Server ([\d\.]+) /i) {
        $dist='sles'.$1;
    } elsif ($versionstring =~ /^SuSE Linux ([\d\.]+) /i) {
        $dist = 'suse'.$1;
    } elsif ($versionstring =~ /^openSUSE ([\d\.]+) /i) {
        $dist = 'suse'.$1;
    } else {
        warn('Unable to interpret /etc/SuSE-release '.
             'to determine system type');
        $unknown = 1;
    }
} elsif (-e '/etc/issue') {
    open(IN,'</etc/issue');
    my $versionstring=<IN>;
    chomp($versionstring);
    close(IN);
    if ($versionstring =~ /^Ubuntu (\d+)\.\d+/i) {
        $dist = 'ubuntu'.$1;
    } elsif ($versionstring =~ /^Debian\s+GNU\/Linux\s+(\d+)\.\d+/i) {
        $dist = 'debian'.$1;
    } elsif (-e '/etc/debian_version') {
        open(IN,'</etc/debian_version');
        my $version=<IN>;
        chomp($version);
        close(IN);
        if ($version =~  /^(\d+)\.\d+\.?\d*/) {
            $dist='debian'.$1;
        } else {
            warn('Unable to interpret /etc/debian_version '.
                 'to determine system type');
            $unknown = 1;
        }
    }
} elsif (-e '/etc/debian_version') {
    open(IN,'</etc/debian_version');
    my $version=<IN>;
    chomp($version);
    close(IN);
    if ($version =~  /^(\d+)\.\d+\.?\d*/) {
        $dist='debian'.$1;
    } else {
        warn('Unable to interpret /etc/debian_version '.
             'to determine system type');
        $unknown = 1;
    }
}
if (($dist eq 'default') && (!$unknown)) {
    if (-e '/etc/os-release') {
        if (open(IN,'<','/etc/os-release')) {
            my ($id,$version);
            while(<IN>) {
                chomp();
                if (/^ID="(\w+)"/) {
                    $id=$1;
                } elsif (/^VERSION_ID="([\d\.]+)"/) {
                    $version=$1;
                }
            }
            close(IN);
            if ($id eq 'sles') {
                my ($major,$minor) = split(/\./,$version);
                if ($major =~ /^\d+$/) {
                    $dist = $id.$major;
                }
            }
        }
        if ($dist eq 'default') {
            warn('Unable to interpret /etc/os-release '.
                 'to determine system type.');
            $unknown = 1;
        }
    } else {
        warn('Unknown installation: expecting a debian, ubuntu, suse, sles, redhat, fedora or scientific linux system.')."\n";
    }
}
print $dist;