my $n = shift;
    my @l;
    push @l, [ splice(@_, 0, $n) ] while @_;
    @l;
}

sub join_lines {
    my @l;
    my $s;
    foreach (@_) {
	if (/^\s/) {
	    $s .= $_;
	} else {
	    push @l, $s if $s;
	    $s = $_;
	}
    }
    @l, if_($s, $s);
}


sub set_alternative {
    my ($command, $executable) = @_;

    #- check the existance of $executable as an alternative for $command
    #- (is this needed???)
    run_program::rooted_get_stdout($::prefix, 'update-alternatives', '--display', $command) =~ /^\Q$executable /m or return;

    #- this does not handle relative symlink, but neither does update-alternatives ;p
    symlinkf $executable, "$::prefix/etc/alternatives/$command";
}

sub files_exist { and_(map { -f "$::prefix$_" } @_) }

sub open_file {
    my ($file) = @_;
    my $F;
    open($F, $file) ? $F : do { log::l("Can not open $file: $!"); undef };
}


sub secured_file {
    my ($f) = @_;
    c::is_secure_file($f) or die "can not ensure a safe $f";
    $f;
}

sub chown_ {
    my ($b_recursive, $name, $group, @files) = @_;

    my ($uid, $gid) = (getpwnam($name) || $name, getgrnam($group) || $group);
      
    require POSIX;
    my $chown; $chown = sub {
	foreach (@_) {
	    POSIX::lchown($uid, $gid, $_) or die "chown of file $_ failed: $!\n";
	    ! -l $_ && -d $_ && $b_recursive and &$chown(glob_($_));
	}
    };
    $chown->(@files);
}


sub set_permissions {
    my ($file, $perms, $o_owner, $o_group) = @_;
    # We only need to set the permissions during installation to be able to
    # print test pages. After installation udev does the business automatically.
    return 1 unless $::isInstall;
    if ($o_owner || $o_group) {
	$o_owner ||= (lstat($file))[4];
	$o_group ||= (lstat($file))[5];
	chown_(0, $o_owner, $o_group, $file);
    }
    chmod(oct($perms), $file) or die "chmod of file $file failed: $!\n";
}

sub parse_release_file {
    my ($prefix, $f, $part) = @_;
    chomp(my $s = cat_("$prefix$f"));
    my $arch = $s =~ s/\s+for\s+(\S+)// && $1;
    log::l("find_root_parts found $part->{device}: $s for $arch" . ($f !~ m!/etc/! ? " in special release file $f" : ''));
    { release => $s, release_file => $f, part => $part, arch => $arch };
}

sub release_file {
    my ($o_dir) = @_;
    my @names = ('mandrakelinux-release', 'mandrake-release', 'conectiva-release', 'release', 'redhat-release', 'fedora-release', 'SuSE-release');
    find { -r "$o_dir$_" } (
	(map { "/root/drakx/$_.upgrading" } @names), 
	(map { "/etc/$_" } @names),
    );
}

sub mandrake_release_info() {
    parse_LDAP_namespace_structure(cat_('/etc/product.id'));
}

sub parse_LDAP_namespace_structure {
    my ($s) = @_;
    my %h = map { if_(/(.*?)=(.*)/, $1 => $2) } split(',', $s);
    \%h;
}

sub mandrake_release {
    my ($o_dir) = @_;
    my $f = release_file($o_dir);
    $f && chomp_(cat_("$o_dir$f"));
}

sub get_parent_uid() {
    cat_('/proc/' . getppid() . '/status') =~ /Uid:\s*(\d+)/ ? $1 : undef;
}

sub wrap_command_for_root {
    my ($name, @args) = @_;
    ([ 'consolehelper', $name ], @args);
}

sub require_root_capability() {
    return if $::testing || !$>; # we're already root

    my ($command, @args) = wrap_command_for_root($0, @ARGV);
    exec { $command->[0] } $command->[1], @args or die N("command %s missing", $command->[0]);

    # still not root ?
    die "you must be root to run this program" if $>;
}

sub check_for_xserver() {
    if (!defined $::xtest) {
	$::xtest = 0;         
	eval { 
	    require xf86misc::main; 
	    $::xtest = xf86misc::main::Xtest($ENV{DISPLAY});
	} if $ENV{DISPLAY};
    }
    return $::xtest;
}

#- special unpack
#- - returning an array refs for each element like "s10"
#- - handling things like s10* at the end of the format
sub unpack_with_refs {
    my ($format, $s) = @_;
    my $initial_format = $format;
    my @r;
    while ($format =~ s/\s*(\w(\d*))(\*?)\s*//) {
	my ($sub_format, $nb, $many) = ($1, $2, $3);
	$many && $format and internal_error("bad * in the middle of format in $initial_format");

	my $done = $many && !length($s);
	while (!$done) {
	    my @l = unpack("$sub_format a*", $s);
	    $s = pop @l;
	    push @r, $nb ? \@l : @l;
	    $done = !$many || !length($s);
	}
    }
    @r;
}

#- used in userdrake and mdkonline
sub md5file {
    require Digest::MD5;
    my @md5 = map {
        my $sum;
	if (open(my $FILE, $_)) {
            binmode($FILE);
            $sum = Digest::MD5->new->addfile($FILE)->hexdigest;
            close($FILE);
        }
        $sum;
    } @_;
    return wantarray() ? @md5 : $md5[0];
}

sub load_modules_from_base {
    my ($base) = @_;
    $base =~ s|::|/|g;
    my $base_file = $base . ".pm";
    require $base_file;
    my ($inc_path) = substr($INC{$base_file}, 0, -length($base_file));
    my @files = map { substr($_, length($inc_path)) } glob_($inc_path . $base . '/*.pm');
    require $_ foreach @files;
    #- return the matching modules list
    map { local $_ = $_; s|/|::|g; s|\.pm$||g; $_ } @files;
}

sub get_alternatives {
    my ($name) = @_;

    my $dir = '/var/lib/rpm/alternatives';
    my ($state, $main_link, @l) = chomp_(cat_("$dir/$name")) or return;
    my @slaves;
    while (@l && $l[0] ne '') {
	my ($name, $link) = splice(@l, 0, 2);
	push @slaves, { name => $name, link => $link };
    }
    shift @l; #- empty line
    my @alternatives;
    while (@l && $l[0] ne '') {
	my ($file, $weight, @slave_files) = splice(@l, 0, 2 + @slaves);
	
	push @alternatives, { file => $file, weight => $weight, slave_files => \@slave_files };
    }
    { name => $name, link => $main_link, state => $state, slaves => \@slaves, alternatives => \@alternatives };
}

sub symlinkf_update_alternatives {
    my ($name, $wanted_file) = @_;
    run_program::rooted($::prefix, 'update-alternatives', '--set', $name, $wanted_file);
}

sub update_gnomekderc_no_create {
    my ($file, $category, %subst_) = @_;
    if (-e $file) {
	update_gnomekderc($file, $category, %subst_);
    }
}

1;