#! /usr/bin/perl

use Cwd;
use File::Basename;
use Sys::Syslog;

sub ExitAndCleanup;
sub Usage;
sub GetAgentRoot;

$AgentRoot = GetAgentRoot($0);
$AgentInstanceGuid = basename($AgentRoot);
$GdmInstall = 1;
$Debug = 0;
$logMask = 15;     # LOG_UPTO(LOG_WARNING)
$logOpts = 'pid';
@SavedArgs = @ARGV;

$SIG{INT} = "ExitAndCleanup";
$SIG{QUIT} = "ExitAndCleanup";

while (@ARGV) {
    if ($ARGV[0] =~ /^-I/ || $ARGV[0] =~ /--install/) {
        $GdmInstall = 1;
    } elsif ($ARGV[0] =~ /^-U/ || $ARGV[0] =~ /--uninstall/) {
        $GdmInstall = 0;
    } elsif ($ARGV[0] =~ /^-D/ || $ARGV[0] =~ /--debug/) {
        $logMask = 255;     # LOG_UPTO(LOG_DEBUG)
        $Debug = 1;
    } elsif ($ARGV[0] =~ /^-V/ || $ARGV[0] =~ /--verbose/) {
        $logOpts = 'pid,cons';
    } elsif ($ARGV[0] =~ /^-/) {
        Usage("Unexpected Option: $ARGV[0]");
        ExitAndCleanup(1);
    } elsif ("$KPanelXml" eq "" && $ARGV[0] =~ m'^/') {
        $KPanelXml = $ARGV[0];
    } else {
        Usage("Unexpected argument: $ARGV[0]");
        ExitAndCleanup(1);
    }
    shift @ARGV;
}

if ( -d "/etc/gdm" ) {
    $etc_gdm = "/etc/gdm";
} elsif ( -d "/etc/opt/gnome/gdm" ) {
    $etc_gdm = "/etc/opt/gnome/gdm";
} else {
    syslog("err", "Cannot file /etc/gdm equivalent directory.\n");
    ExitAndCleanup(1);
}

openlog('[KaInstallGdmUser]', $logOpts, 'user'); 
setlogmask $logMask;

if ($GdmInstall) {
    syslog("info", "Starting KaInstallGdmUser in install mode");
    if (! -d "$etc_gdm/PreSession") {
        syslog('err', "Missing \"$etc_gdm/PreSession\" directory.");
        ExitAndCleanup(1);
    }

    if (-e "$etc_gdm/PreSession/Default") {
        $doit = 1;

        # Since many Linux distros have a PreSession/Default file which execs sessreg,
        # its better to add our magic at the start. We do read the file through first
        # to make sure we're not doing a duplicate install. We also need to make sure
        # and remove a "--uninstall" flag if we're installing.
        open(IN, "< $etc_gdm/PreSession/Default") || die "Can not open Default file.\n";

        while (<IN>) {
            next if /^\s*#/;

            $uninstDir = "$AgentRoot" . "_Uninstalled";
            if (m"$uninstDir/libexec/KaGdmUser") {
                syslog('debug', "Switching KaGdmUser from uninstall to install mode in PreSession/Default");
                $doit = 2;
                last;
            } elsif (m"$AgentRoot/libexec/KaGdmUser") {
                syslog('debug', "Found reference to KaGdmuser in PreSession/Default");
                $doit = 0;
            }
        }

        if ($doit) {
            seek(IN, 0, 0);             # Go back to the beginning of the file
            open(OUT, "> $etc_gdm/PreSession/Default$$") || die "Can not create new Default file.\n";
            if ($doit == 1) {   # insert mode
                syslog('debug', "Adding to existing PreSession/Default file.");
                while (<IN>) {
                    last if ! /^#/;
                    print OUT;
                }
                $firstLine = $_;
                print OUT "\n";
                print OUT "if [ -x \"$AgentRoot/libexec/KaGdmUser\" ]\n";
                print OUT "then\n";
                print OUT "    $AgentRoot/libexec/KaGdmUser\n";
                print OUT "fi\n\n";
                print OUT "$firstLine" if ! m"^\s*$";
                while (<IN>) {
                    print OUT;
                }
            } else {
                # Change KaGdmUser --uninstall to install mode
                syslog('debug', "Switching existing PreSession/Default file from uninstall to install mode.");
                while (<IN>) {
                    if (m"/libexec/KaGdmUser") {
                        syslog('debug', "Found uninstall code.");
                        s/_Uninstalled//;
                        s/ --uninstall//;
                    }
                    print OUT;
                }
            }
            close(IN);
            close(OUT);
            rename("$etc_gdm/PreSession/Default", "$etc_gdm/PreSession/Default.old");
            rename("$etc_gdm/PreSession/Default$$", "$etc_gdm/PreSession/Default");
        }
    } else {
        syslog('debug', "Creating new PreSession/Default file.");
        open(OUT, "> $etc_gdm/PreSession/Default") || die "Can not Create Default file.\n";
        print OUT "#! /bin/sh\n";
        print OUT "\n";
        print OUT "if [ -x \"$AgentRoot/libexec/KaGdmUser\" ]\n";
        print OUT "then\n";
        print OUT "    $AgentRoot/libexec/KaGdmUser\n";
        print OUT "fi\n";
        close(OUT);
    }
    chmod(0755, "$etc_gdm/PreSession/Default");
    if (-d "$AgentRoot" . "_Uninstalled/libexec") {
        syslog('debug', "Removing $AgentRoot" . "_Uninstalled directory.");
        system "rm", "-rf", "$AgentRoot" . "_Uninstalled";
    }

    open(IN, "< /etc/passwd") || die "Can't open /etc/passwd.\n";
    while (<IN>) {
        chomp;
        ($login, $x, $x, $group, $x, $home, $shell) = split /:/;
        if ($shell !~ m'/sbin/nologin' && $shell !~ m'/bin/false' && -d "$home/.gconf") {
            system "$AgentRoot/libexec/KaGdmUser", "-u", "$login", "-g", "$group", "-h", "$home";
        }
    }
    close(IN);
} else {            # Uninstall
    syslog('info', "Starting KaInstallGdmUser in uninstall mode");
    $uninstDir = "$AgentRoot" . "_Uninstalled";
    if (-x "$AgentRoot/libexec/KaGdmUser" && ! -d "$uninstDir") {
        mkdir "$uninstDir", 0755;
        mkdir "$uninstDir/libexec", 0755;
        system "cp", "$AgentRoot/libexec/KaGdmUser", "$uninstDir/libexec";
        open(README, "> $uninstDir/README") || die "Cannot create README file explaining uninstall rules.\n";
        print README "This directory contains a post-uninstall script which cleans up user\n";
        print README "logins after the Agent has been uninstalled. Removing this directory\n";
        print README "can cause errors during future logins for some users.\n";
        close(README);
    }

    open(IN, "< $etc_gdm/PreSession/Default") || die "Can not open Default file.\n";
    open(OUT, "> $etc_gdm/PreSession/Default$$") || die "Can not create new Default file.\n";

    while (<IN>) {
        if (m"$AgentRoot/libexec/KaGdmUser") {
            syslog('debug', "Found KaGdmUser we want to change.");
            s/$AgentRoot/$uninstDir/;
            print OUT; # m"\s*if\b";
            $_ = <IN>;
            print OUT; # m"\s*then\b";
            <IN>;      # read and replace this line
            print OUT "    $uninstDir/libexec/KaGdmUser --uninstall\n";
            next;
        }
        print OUT;
    }
    close(IN);
    close(OUT);
    rename("$etc_gdm/PreSession/Default", "$etc_gdm/PreSession/Default.old");
    rename("$etc_gdm/PreSession/Default$$", "$etc_gdm/PreSession/Default");
    chmod(0755, "$etc_gdm/PreSession/Default");

    open(IN, "< /etc/passwd") || die "Can't open /etc/passwd.\n";
    while (<IN>) {
        chomp;
        ($login, $x, $x, $group, $x, $home, $shell) = split /:/;
        if ($shell !~ m'/sbin/nologin' && $shell !~ m'/bin/false' && -d "$home/.gconf") {
            system "$AgentRoot/libexec/KaGdmUser", "--uninstall", "-u", "$login", "-g", "$group", "-h", "$home";
        }
    }
    close(IN);
}

ExitAndCleanup(0);

sub GetAgentRoot {
    my $pgm = $_[0];"-x", 
    my $cwd = getcwd();
    my $path;

    if ($pgm =~ m'^/') {
        $path = dirname("$pgm");
    } else {
        $path = dirname("$cwd/$pgm");
    }

    chdir("$path/..");
    $path = getcwd();
    chdir($cwd);
    return $path;
}

sub Usage {
    syslog('info', "%s\n", "$_[0]");
    print("Warning: $_[0]\n");
    print("Usage:   KaInstallGdmUser.pl [ -s ]\n");
}

sub ExitAndCleanup {
    if ($_[0] != '0') {
        syslog('info', "Exiting with %s return code.\n", "$_[0]");
    }
    exit $_[0];
}