path: root/urpm/media.pm

package urpm::media;

# $Id$

use urpm 'file_from_local_url';
use urpm::msg;
use urpm::util;
use urpm::removable;
use urpm::lock;
use MDV::Distribconf;


our @PER_MEDIA_OPT = qw(
    downloader
    hdlist
    ignore
    key-ids
    list
    media_info_dir
    name
    noreconfigure
    priority-upgrade
    removable
    static
    synthesis
    update
    url
    verify-rpm
    virtual
    with_hdlist
    with_synthesis
);

sub only_media_opts {
    my ($m) = @_;
    my %m = map { $_ => $m->{$_} } grep { defined $m->{$_} } @PER_MEDIA_OPT;
    \%m;
}

sub read_private_netrc {
    my ($urpm) = @_;

    my @words = split(/\s+/, scalar cat_($urpm->{private_netrc}));
    my @l;
    my $e;
    while (@words) {
	my $keyword = shift @words;
	if ($keyword eq 'machine') {
	    push @l, $e = { machine => shift(@words) };
	} elsif ($keyword eq 'default') {
	    push @l, $e = { default => '' };
	} elsif ($keyword eq 'login' || $keyword eq 'password' || $keyword eq 'account') {
	    $e->{$keyword} = shift(@words);
	} else {
	    $urpm->{error}("unknown netrc command $keyword");
	}
    }
    @l;
}

sub read_config_add_passwords {
    my ($urpm, $config) = @_;

    my @netrc = read_private_netrc($urpm) or return;
    foreach (@{$config->{media}}) {
	my $u = urpm::download::parse_url_with_login($_->{url}) or next;
	if (my ($e) = grep { ($_->{default} || $_->{machine} eq $u->{machine}) && $_->{login} eq $u->{login} } @netrc) {
	    $_->{url} = sprintf('%s://%s:%s@%s%s', $u->{proto}, $u->{login}, $e->{password}, $u->{machine}, $u->{dir});
	} else {
	    $urpm->{log}(sprintf('no password found for %s@%s', $u->{login}, $u->{machine}));
	}
    }
}

sub remove_passwords_and_write_private_netrc {
    my ($urpm, $config) = @_;

    my @l;
    foreach (@{$config->{media}}) {
	my $u = urpm::download::parse_url_with_login($_->{url}) or next;
	#- check whether a password is visible
	$u->{password} or next;

	push @l, $u;
	$_->{url} = sprintf('%s://%s@%s%s', $u->{proto}, $u->{login}, $u->{machine}, $u->{dir});
    }
    {
	my $fh = urpm::sys::open_safe($urpm, '>', $urpm->{private_netrc}) or return;
	foreach my $u (@l) {
	    printf $fh "machine %s login %s password %s\n", $u->{machine}, $u->{login}, $u->{password};
	}
    }
    chmod 0600, $urpm->{private_netrc};
}

#- handle deprecated way of saving passwords
sub recover_url_from_list {
    my ($urpm, $medium) = @_;

    my $list = delete $medium->{list} or return;
    my $statedir_list = "$urpm->{statedir}/$list";

    #- /./ is end of url marker in list file (typically generated by a
    #- find . -name "*.rpm" > list
    #- for exportable list file.
    if (my @probe = map { m!^(.*)/\./! || m!^(.*)/[^/]*$! } cat_($statedir_list)) {
	$urpm->{log}("recovering url from $statedir_list");
	($medium->{url}) = sort { length($a) <=> length($b) } @probe;
	$urpm->{modified} = 1; #- ensure urpmi.cfg is handled using only partially hidden url + netrc, since file list won't be generated anymore
	unlink $statedir_list;
    }
}

#- Loads /etc/urpmi/urpmi.cfg and performs basic checks.
#- Does not handle old format: <name> <url> [with <path_hdlist>]
#- options :
#-    - nocheck_access : don't check presence of synthesis and other files
sub read_config {
    my ($urpm, $b_nocheck_access) = @_;
    return if $urpm->{media}; #- media already loaded
    $urpm->{media} = [];
    my $config = urpm::cfg::load_config($urpm->{config})
	or $urpm->{fatal}(6, $urpm::cfg::err);

    #- per-media options
    read_config_add_passwords($urpm, $config);

    foreach my $m (@{$config->{media}}) {
	my $medium = only_media_opts($m);

	if (!$medium->{url}) {
	    #- recover the url the old deprecated way...
	    #- only useful for migration, new urpmi.cfg will use netrc
	    recover_url_from_list($urpm, $medium);
	    $medium->{url} or $urpm->{error}("unable to find url in list file $medium->{name}, medium ignored");
	}

	add_existing_medium($urpm, $medium, $b_nocheck_access);
    }

    eval { require urpm::ldap; urpm::ldap::load_ldap_media($urpm) };
}

#- if invalid, set {ignore}
sub check_existing_medium {
    my ($urpm, $medium, $b_nocheck_access) = @_;

    my $err;
    if (!$medium->{url}) { 
	$err = $medium->{virtual} ?
	  N("virtual medium \"%s\" should have a clear url, medium ignored",
			   $medium->{name}) :
	  N("unable to access list file of \"%s\", medium ignored", $medium->{name});
    } elsif (!$b_nocheck_access && !$medium->{ignore} 
	     && !-r any_synthesis($urpm, $medium)) {
	$err = N("unable to access synthesis file of \"%s\", medium ignored", $medium->{name});
    }
    if ($err) {
	$medium->{ignore} = 1;
	$urpm->{error}($err);
    }
}

sub _migrate__with_synthesis {
    my ($medium, $with_synthesis) = @_;

    #- try to migrate to media_info_dir
    my $b = basename($with_synthesis);
    if ($b eq 'synthesis.hdlist.cz' || $b eq 'hdlist.cz') {
	$medium->{media_info_dir} = dirname($with_synthesis);
    } else {
	$with_synthesis =~ s/(synthesis\.)?(hdlist.*\.cz)$/synthesis.$2/;
	$medium->{with_synthesis} = $with_synthesis;
    }
}

#- probe medium to be used, take old medium into account too.
sub add_existing_medium {
    my ($urpm, $medium, $b_nocheck_access) = @_;

    if (name2medium($urpm, $medium->{name})) {
	$urpm->{error}(N("trying to override existing medium \"%s\", skipping", $medium->{name}));
	return;
    }

    if ($medium->{with_hdlist}) {
	_migrate__with_synthesis($medium, delete $medium->{with_hdlist});
	$urpm->{modified} = 1;
    }

    check_existing_medium($urpm, $medium, $b_nocheck_access);

    #- probe removable device.
    probe_removable_device($urpm, $medium);

    #- clear URLs for trailing /es.
    $medium->{url} and $medium->{url} =~ s|(.*?)/*$|$1|;

    push @{$urpm->{media}}, $medium;
}

sub file_from_file_url {
    my ($url) = @_;
    $url =~ m!^(?:file:/)?(/.*)! && $1;
}

sub _url_with_synthesis_basename {
    my ($medium) = @_;

    $medium->{with_synthesis}
      ? basename($medium->{with_synthesis})
      : 'synthesis.hdlist.cz';
}
sub _synthesis_dir {
    my ($medium) = @_;
    my $base = file_from_local_url($medium->{url}) || $medium->{url};
    $medium->{with_synthesis}
      ? reduce_pathname("$base/$medium->{with_synthesis}/..")
      : $medium->{media_info_dir} && reduce_pathname("$base/$medium->{media_info_dir}");
}
sub _url_with_synthesis {
    my ($medium) = @_;

    my $base = file_from_local_url($medium->{url}) || $medium->{url};
    $medium->{with_synthesis}
      ? reduce_pathname("$base/$medium->{with_synthesis}")
      : _synthesis_dir($medium) . "/" . _url_with_synthesis_basename($medium);

}
sub synthesis_for_virtual_medium {
    my ($medium) = @_;
    file_from_file_url($medium->{url}) && _url_with_synthesis($medium);
}

sub _synthesis {
    my ($medium) = @_;
    $medium->{name} && "synthesis.hdlist.$medium->{name}.cz";
}

sub statedir_synthesis {
    my ($urpm, $medium) = @_;
    "$urpm->{statedir}/" . _synthesis($medium);
}
sub statedir_descriptions {
    my ($urpm, $medium) = @_;
    $medium->{name} && "$urpm->{statedir}/descriptions.$medium->{name}";
}
sub statedir_names {
    my ($urpm, $medium) = @_;
    $medium->{name} && "$urpm->{statedir}/names.$medium->{name}";
}
sub statedir_MD5SUM {
    my ($urpm, $medium) = @_;
    $medium->{name} && "$urpm->{statedir}/MD5SUM.$medium->{name}";
}
sub cachedir_with_synthesis {
    my ($urpm, $medium) = @_;
    _url_with_synthesis($medium) && "$urpm->{cachedir}/partial/" . _url_with_synthesis_basename($medium);
}
sub any_synthesis {
    my ($urpm, $medium) = @_;
    my $f = $medium->{virtual} ? _url_with_synthesis($medium)
      : statedir_synthesis($urpm, $medium);
    -e $f && $f;
}

sub name2medium {
    my ($urpm, $name) = @_;
    my ($medium) = grep { $_->{name} eq $name } @{$urpm->{media}};
    $medium;
}

#- probe device associated with a removable device.
sub probe_removable_device {
    my ($urpm, $medium) = @_;

    if ($medium->{url} && $medium->{url} =~ /^removable/) {
	#- try to find device name in url scheme, this is deprecated, use medium option "removable" instead
	if ($medium->{url} =~ /^removable_?([^_:]*)/) {
	    $medium->{removable} ||= $1 && "/dev/$1";
	}
    } else {
	delete $medium->{removable};
	return;
    }

    #- try to find device to open/close for removable medium.
    if (my $dir = file_from_local_url($medium->{url})) {
	my %infos;
	my @mntpoints = urpm::sys::find_mntpoints($dir, \%infos);
	if (@mntpoints > 1) {	#- return value is suitable for an hash.
	    $urpm->{log}(N("too many mount points for removable medium \"%s\"", $medium->{name}));
	    $urpm->{log}(N("taking removable device as \"%s\"", join ',', map { $infos{$_}{device} } @mntpoints));
	}
	if (urpm::removable::is_iso($medium->{removable})) {
	    $urpm->{log}(N("Medium \"%s\" is an ISO image, will be mounted on-the-fly", $medium->{name}));
	} elsif (@mntpoints) {
	    if ($medium->{removable} && $medium->{removable} ne $infos{$mntpoints[-1]}{device}) {
		$urpm->{log}(N("using different removable device [%s] for \"%s\"",
			       $infos{$mntpoints[-1]}{device}, $medium->{name}));
	    }
	    $medium->{removable} = $infos{$mntpoints[-1]}{device};
	} else {
	    $urpm->{error}(N("unable to retrieve pathname for removable medium \"%s\"", $medium->{name}));
	}
    } else {
	$urpm->{error}(N("unable to retrieve pathname for removable medium \"%s\"", $medium->{name}));
    }
}


#- Writes the urpmi.cfg file.
sub write_urpmi_cfg {
    my ($urpm) = @_;

    #- avoid trashing exiting configuration if it wasn't loaded
    $urpm->{media} or return;

    my $config = {
	#- global config options found in the config file, without the ones
	#- set from the command-line
	global => $urpm->{global_config},
	media => [ map { only_media_opts($_) } grep { !$_->{external} } @{$urpm->{media}} ],
    };
    remove_passwords_and_write_private_netrc($urpm, $config);

    urpm::cfg::dump_config($urpm->{config}, $config)
	or $urpm->{fatal}(6, N("unable to write config file [%s]", $urpm->{config}));

    $urpm->{log}(N("wrote config file [%s]", $urpm->{config}));

    #- everything should be synced now.
    delete $urpm->{modified};
}

sub write_config {
    my ($urpm) = @_;

    write_urpmi_cfg($urpm);
}

sub _tempignore {
    my ($medium, $ignore) = @_;
    $medium->{ignore} = $ignore;
}

#- read urpmi.cfg file as well as necessary synthesis files
#- options :
#-	root (deprecated, set directly $urpm->{root})
#-	cmdline_skiplist
#-      nocheck_access (used by read_config)
#-
#-	callback (urpmf)
#-	need_xml (for urpmf: to be able to have info not available in synthesis)
#-	nodepslist (for urpmq: we don't need the synthesis)
#-	no_skiplist (urpmf)
#-      no_second_pass (urpmf)
#-
#-	synthesis (use this synthesis file, and only this synthesis file)
#-
#-	parallel
#-	usedistrib (otherwise uses urpmi.cfg)
#-	  media
#-	  excludemedia
#-	  sortmedia
#-
#-	  update
#-	  searchmedia
sub configure {
    my ($urpm, %options) = @_;

    clean($urpm);

    $options{parallel} && $options{usedistrib} and $urpm->{fatal}(1, N("Can't use parallel mode with use-distrib mode"));

    if ($options{parallel}) {
	require urpm::parallel;
	urpm::parallel::configure($urpm, $options{parallel});

	if (!$options{media} && $urpm->{parallel_handler}{media}) {
	    $options{media} = $urpm->{parallel_handler}{media};
	    $urpm->{log}->(N("using associated media for parallel mode: %s", $options{media}));
	}
    } else {
	#- nb: can't have both parallel and root
	$urpm->{root} = $options{root} if $options{root};
    }

    if ($urpm->{root} && ! -c "$urpm->{root}/dev/null") {
	mkdir "$urpm->{root}/dev";
	system("/bin/cp", "-a", '/dev/null', "$urpm->{root}/dev");
    }

    if ($options{synthesis}) {
	if ($options{synthesis} ne 'none') {
	    #- synthesis take precedence over media, update options.
	    $options{media} || $options{excludemedia} || $options{sortmedia} || $options{update} || $options{usedistrib} || $options{parallel} and
	      $urpm->{fatal}(1, N("--synthesis cannot be used with --media, --excludemedia, --sortmedia, --update, --use-distrib or --parallel"));
	    $urpm->parse_synthesis($options{synthesis});
	    #- synthesis disables the split of transaction (too risky and not useful).
	    $urpm->{options}{'split-length'} = 0;
	}
    } else {
        if ($options{usedistrib}) {
            $urpm->{media} = [];
            add_distrib_media($urpm, "Virtual", $options{usedistrib}, %options, 'virtual' => 1);
        } else {
	    read_config($urpm, $options{nocheck_access});
	    if (!$options{media} && $urpm->{options}{'default-media'}) {
		$options{media} = $urpm->{options}{'default-media'};
	    }
        }
	if ($options{media}) {
	    delete $_->{modified} foreach @{$urpm->{media} || []};
	    select_media($urpm, split /,/, $options{media});
	    foreach (@{$urpm->{media} || []}) {
		_tempignore($_, !$_->{modified});
	    }
	}
	if ($options{searchmedia}) {
	   foreach (select_media_by_name($urpm, [ split /,/, $options{searchmedia} ])) {
	       #- Ensure this media is selected
	       $_->{modified} = 1;
	       _tempignore($_, 0);
	       $_->{searchmedia} = 1;
	   }
	}
	if ($options{excludemedia}) {
	    delete $_->{modified} foreach @{$urpm->{media} || []};
	    foreach (select_media_by_name($urpm, [ split /,/, $options{excludemedia} ])) {
		$_->{modified} = 1;
		#- this is only a local ignore that will not be saved.
		_tempignore($_, 1);
	    }
	}
	if ($options{sortmedia}) {
	    my @sorted_media = map { select_media_by_name($urpm, [$_]) } split(/,/, $options{sortmedia});
	    my @remaining = difference2($urpm->{media}, \@sorted_media);
	    $urpm->{media} = [ @sorted_media, @remaining ];
	}
	_parse_media($urpm, \%options) if !$options{nodepslist};
    }
    #- determine package to withdraw (from skip.list file) only if something should be withdrawn.
    if (!$options{nodepslist}) {
	_compute_flags_for_skiplist($urpm, $options{cmdline_skiplist}) if !$options{no_skiplist};
	_compute_flags_for_instlist($urpm);
    }
}

sub _parse_media {
    my ($urpm, $options) = @_;

    foreach (grep { !$_->{ignore} && (!$options->{update} || $_->{update}) } @{$urpm->{media} || []}) {
	our $currentmedia = $_; #- hack for urpmf
	delete @$_{qw(start end)};
	_parse_synthesis_or_ignore($urpm, $_, $options->{callback});

	if ($options->{need_xml}) {
	    # TODO
	    # _parse_xml_($urpm, $_, any_xml($urpm, $_), $options->{callback});
	}
	if ($_->{searchmedia}) {
	    $urpm->{searchmedia} = 1;
	    $urpm->{log}(N("Search start: %s end: %s", $_->{start}, $_->{end}));
	}
    }
}

sub _compute_flags_for_skiplist {
    my ($urpm, $cmdline_skiplist) = @_;
    my %uniq;
    $urpm->compute_flags(
	urpm::sys::get_packages_list($urpm->{skiplist}, $cmdline_skiplist),
	skip => 1,
	callback => sub {
	    my ($urpm, $pkg) = @_;
	    $pkg->is_arch_compat && ! exists $uniq{$pkg->fullname} or return;
	    $uniq{$pkg->fullname} = undef;
	    $urpm->{log}(N("skipping package %s", scalar($pkg->fullname)));
	},
    );
}

sub _compute_flags_for_instlist {
    my ($urpm) = @_;

    my %uniq;
    $urpm->compute_flags(
	urpm::sys::get_packages_list($urpm->{instlist}),
	disable_obsolete => 1,
	callback => sub {
	    my ($urpm, $pkg) = @_;
	    $pkg->is_arch_compat && ! exists $uniq{$pkg->fullname} or return;
	    $uniq{$pkg->fullname} = undef;
	    $urpm->{log}(N("would install instead of upgrade package %s", scalar($pkg->fullname)));
	},
    );

}

#- add a new medium, sync the config file accordingly.
#- returns the new medium's name. (might be different from the requested
#- name if index_name was specified)
#- options: ignore, index_name, nolock, update, virtual, media_info_dir
sub add_medium {
    my ($urpm, $name, $url, $with_synthesis, %options) = @_;

    #- make sure configuration has been read.
    $urpm->{media} or die "caller should have used ->read_config or ->configure first";

    #- if a medium with that name has already been found, we have to exit now
    if (defined $options{index_name}) {
	my ($i, $basename) = ($options{index_name}, $name);
	while (1) {
	    ++$i;
	    $name = $basename . ($i == 1 ? '' : $i);
	    last if !name2medium($urpm, $name);
	}
    } else {
	name2medium($urpm, $name) and $urpm->{fatal}(5, N("medium \"%s\" already exists", $name));
    }

    $url =~ s,/*$,,; #- clear URLs for trailing /es.

    #- creating the medium info.
    my $medium = { name => $name, 
		url => $url, 
		modified => !$options{ignore}, 
	    };
    foreach (qw(downloader update ignore media_info_dir)) {
	$medium->{$_} = $options{$_} if exists $options{$_};
    }

    if ($options{virtual}) {
	file_from_file_url($url) or $urpm->{fatal}(1, N("virtual medium needs to be local"));
	$medium->{virtual} = 1;
    } else {
	probe_removable_device($urpm, $medium);
    }

    if ($with_synthesis) {
	_migrate__with_synthesis($medium, $with_synthesis);
    }

    #- local media have priority, other are added at the end.
    my $inserted;
    my $ignore_text = $medium->{ignore} ? ' ' . N("(ignored by default)") : '';
    if (file_from_file_url($url)) {
	#- insert before first remote medium
	@{$urpm->{media}} = map {  
	    if (!file_from_file_url($_->{url}) && !$inserted) {
		$inserted = 1;
		$urpm->{info}(N("adding medium \"%s\" before remote medium \"%s\"", $name, $_->{name}) . $ignore_text);
		$medium, $_;
	    } else { $_ }
	} @{$urpm->{media}};
    }
    if (!$inserted) {
	$urpm->{info}(N("adding medium \"%s\"", $name) . $ignore_text);
	push @{$urpm->{media}}, $medium;
    }

    $urpm->{modified} = 1;

    $name;
}

#- add distribution media, according to url given.
#- returns the list of names of added media.
#- options :
#- - initial_number : when adding several numbered media, start with this number
#- - probe_with : force use of rpms instead of using synthesis
#- - ask_media : callback to know whether each media should be added
#- - only_updates : only add "update" media (used by rpmdrake)
#- other options are passed to add_medium(): ignore, nolock, virtual
sub add_distrib_media {
    my ($urpm, $name, $url, %options) = @_;

    #- make sure configuration has been read.
    $urpm->{media} or die "caller should have used ->read_config or ->configure first";

    my $distribconf;

    if (my $dir = file_from_local_url($url)) {
	urpm::removable::try_mounting($urpm, $dir)
	    or $urpm->{error}(N("unable to mount the distribution medium")), return ();
	$distribconf = MDV::Distribconf->new($dir, undef);
	$distribconf->load
	    or $urpm->{error}(N("this location doesn't seem to contain any distribution")), return ();
    } else {
	unlink "$urpm->{cachedir}/partial/media.cfg";

	$distribconf = MDV::Distribconf->new($url, undef);
	$distribconf->settree('mandriva');

	$urpm->{log}(N("retrieving media.cfg file..."));
	if (urpm::download::sync($urpm, undef,
				 [ reduce_pathname($distribconf->getfullpath(undef, 'infodir') . '/media.cfg') ],
				 quiet => 1)) {
	    $distribconf->parse_mediacfg("$urpm->{cachedir}/partial/media.cfg")
		or $urpm->{error}(N("unable to parse media.cfg")), return();
	} else {
	    $urpm->{error}(N("...retrieving failed: %s", $@));
	    $urpm->{error}(N("unable to access the distribution medium (no media.cfg file found)"));
	    return ();
	}
    }

    #- cosmetic update of name if it contains spaces.
    $name =~ /\s/ and $name .= ' ';

    my @newnames;
    #- at this point, we have found a media.cfg file, so parse it
    #- and create all necessary media according to it.
    my $medium_index = $options{initial_number} || 1;

    foreach my $media ($distribconf->listmedia) {
        my $media_name = $distribconf->getvalue($media, 'name') || '';

        if (my $media_arch = $distribconf->getvalue($media, 'arch')) {
            if (!URPM::archscore($media_arch)) {
                $urpm->{log}(N("skipping non compatible media `%s' (for %s)",
			       $media, $media_arch));
                next;
            }
        }
        my $add_by_default = !$distribconf->getvalue($media, 'noauto');
        if ($options{ask_media}) {
            $options{ask_media}->($media_name, $add_by_default) or next;
        } else {
	    my $simple_rpms = !$distribconf->getvalue($media, 'debug_for') && 
	                      !$distribconf->getvalue($media, 'rpms');
	    $add_by_default || $simple_rpms or next;
	}

	my $is_update_media = $distribconf->getvalue($media, 'updates_for');
	if ($options{only_updates}) {
	    $is_update_media or next;
	}

	my $use_copied_synthesis = $urpm->{options}{use_copied_hdlist} || $distribconf->getvalue($media, 'use_copied_hdlist');
	my $with_synthesis = $use_copied_synthesis && offset_pathname(
		$url,
		$distribconf->getpath($media, 'path'),
	    ) . '/' . $distribconf->getpath($media, 'synthesis');

	push @newnames, add_medium($urpm,
	    $name ? "$media_name ($name$medium_index)" : $media_name,
	    reduce_pathname($distribconf->getfullpath($media, 'path')),
	    $with_synthesis, 
	    !$use_copied_synthesis ? (media_info_dir => 'media_info') : (),
	    !$use_copied_synthesis && $options{probe_with} ? ($options{probe_with} => 1) : (),
	    index_name => $name ? undef : 0,
	    $add_by_default ? () : (ignore => 1),
	    %options,
	    # the following override %options
	    update => $is_update_media ? 1 : undef,
	);
	++$medium_index;
    }
    return @newnames;
}

#- deprecated, use select_media_by_name instead
sub select_media {
    my $urpm = shift;
    my $options = {};
    if (ref $_[0]) { $options = shift }
    foreach (select_media_by_name($urpm, [ @_ ], $options->{strict_match})) {
	#- select medium by setting the modified flag, do not check ignore.
	$_->{modified} = 1;
    }
}

sub select_media_by_name {
    my ($urpm, $names, $b_strict_match) = @_;

    my %wanted = map { $_ => 1 } @$names;

    #- first the exact matches
    my @l = grep { delete $wanted{$_->{name}} } @{$urpm->{media}};

    #- check if some arguments don't correspond to the medium name.
    #- in such case, try to find the unique medium (or list candidate
    #- media found).
    foreach (keys %wanted) {
	my $q = quotemeta;
	my (@found, @foundi);
	my $regex  = $b_strict_match ? qr/^$q$/  : qr/$q/;
	my $regexi = $b_strict_match ? qr/^$q$/i : qr/$q/i;
	foreach my $medium (@{$urpm->{media}}) {
	    $medium->{name} =~ $regex  and push @found, $medium;
	    $medium->{name} =~ $regexi and push @foundi, $medium;
	}
	@found = @foundi if !@found;

	if (@found == 0) {
	    $urpm->{error}(N("trying to select nonexistent medium \"%s\"", $_));
	} else {
	    if (@found > 1) {
		$urpm->{log}(N("selecting multiple media: %s", join(", ", map { qq("$_->{name}") } @found)));
	    }
	    #- changed behaviour to select all occurences by default.
	    push @l, @found;
	}
    }
    @l;
}

#- deprecated, use remove_media instead
sub remove_selected_media {
    my ($urpm) = @_;

    remove_media($urpm, [ grep { $_->{modified} } @{$urpm->{media}} ]);
}

sub remove_media {
    my ($urpm, $to_remove) = @_;

    foreach my $medium (@$to_remove) {
	$urpm->{info}(N("removing medium \"%s\"", $medium->{name}));

	#- mark to re-write configuration.
	$urpm->{modified} = 1;

	#- remove files associated with this medium.
	unlink grep { $_ } map { $_->($urpm, $medium) } \&statedir_synthesis, \&statedir_descriptions, \&statedir_names;

	#- remove proxy settings for this media
	urpm::download::remove_proxy_media($medium->{name});
    }

    $urpm->{media} = [ difference2($urpm->{media}, $to_remove) ];
}

sub _probe_with_try_list {
    my ($urpm, $medium, $f) = @_;

    my @media_info_dirs = ('media_info', '.');

    my $base = file_from_local_url($medium->{url}) || $medium->{url};

    foreach my $media_info_dir (@media_info_dirs) {
	my $url = reduce_pathname("$base/$media_info_dir") . '/synthesis.hdlist.cz';
	if ($f->($url)) {
	    $urpm->{debug} and $urpm->{debug}("found synthesis: $url");
	    $medium->{media_info_dir} = $media_info_dir;
	    return 1;
	}
    }
    undef;
}

sub may_reconfig_urpmi {
    my ($urpm, $medium) = @_;

    my $f;
    if (my $dir = file_from_local_url($medium->{url})) {
	$f = reduce_pathname("$dir/reconfig.urpmi");
    } else {
	unlink($f = "$urpm->{cachedir}/partial/reconfig.urpmi");
	urpm::download::sync($urpm, $medium, [ reduce_pathname("$medium->{url}/reconfig.urpmi") ], quiet => 1);
    }
    if (-s $f) {
	reconfig_urpmi($urpm, $f, $medium);
    }
    unlink $f if !file_from_local_url($medium->{url});
}

#- read a reconfiguration file for urpmi, and reconfigure media accordingly
#- $rfile is the reconfiguration file (local), $name is the media name
#-
#- the format is similar to the RewriteRule of mod_rewrite, so:
#-    PATTERN REPLACEMENT [FLAG]
#- where FLAG can be L or N
#-
#- example of reconfig.urpmi:
#-    # this is an urpmi reconfiguration file
#-    /cooker /cooker/$ARCH
sub reconfig_urpmi {
    my ($urpm, $rfile, $medium) = @_;
    -r $rfile or return;

    $urpm->{log}(N("reconfiguring urpmi for media \"%s\"", $medium->{name}));

    my ($magic, @lines) = cat_($rfile);
    #- the first line of reconfig.urpmi must be magic, to be sure it's not an error file
    $magic =~ /^# this is an urpmi reconfiguration file/ or return undef;

    my @replacements;
    foreach (@lines) {
	chomp;
	s/^\s*//; s/#.*$//; s/\s*$//;
	$_ or next;
	my ($p, $r, $f) = split /\s+/, $_, 3;
	push @replacements, [ quotemeta $p, $r, $f || 1 ];
    }

    my $reconfigured = 0;
    my @reconfigurable = qw(url with_synthesis media_info_dir);

    my %orig = %$medium;

  URLS:
    foreach my $k (@reconfigurable) {
	foreach my $r (@replacements) {
	    if ($medium->{$k} =~ s/$r->[0]/$r->[1]/) {
		$reconfigured = 1;
		#- Flags stolen from mod_rewrite: L(ast), N(ext)
		if ($r->[2] =~ /L/) {
		    last;
		} elsif ($r->[2] =~ /N/) { #- dangerous option
		    redo URLS;
		}
	    }
	}
	#- check that the new url exists before committing changes (local mirrors)
	my $file = file_from_local_url($medium->{$k});
	if ($file && !-e $file) {
	    %$medium = %orig;
	    $reconfigured = 0;
	    $urpm->{log}(N("...reconfiguration failed"));
	    return;
	}
    }

    if ($reconfigured) {
	$urpm->{log}(N("reconfiguration done"));
	$urpm->{modified} = 1;
    }
    $reconfigured;
}

sub _guess_synthesis_suffix {
    my ($url) = @_;
    $url =~ m!\bmedia/(\w+)/*\Z! && $1;
}

sub _synthesis_suffix {
    my ($medium) = @_;
    $medium->{with_synthesis} =~ /synthesis\.hdlist(.*?)(?:\.src)?\.cz$/ ? $1 : '';
}

#- names.<media_name> is used by external progs (namely for bash-completion)
sub generate_medium_names {
    my ($urpm, $medium) = @_;

    unlink statedir_names($urpm, $medium);

    if (my $fh = urpm::sys::open_safe($urpm, ">", statedir_names($urpm, $medium))) {
	foreach ($medium->{start} .. $medium->{end}) {
	    if (defined $urpm->{depslist}[$_]) {
		print $fh $urpm->{depslist}[$_]->name . "\n";
	    } else {
		$urpm->{error}(N("Error generating names file: dependency %d not found", $_));
	    }
	}
    } else {
	$urpm->{error}(N("Error generating names file: Can't write to file (%s)", $!));
    }
}


sub _read_existing_synthesis {
    my ($urpm, $medium) = @_;

    unlink cachedir_with_synthesis($urpm, $medium);

    $urpm->{info}(N("medium \"%s\" is up-to-date", $medium->{name}));

    #- the medium is now considered not modified.
    $medium->{modified} = 0;
    #- XXX we could link the new synthesis to the old one.
    #- (However links need to be managed. see bug #12391.)
    #- as previously done, just read synthesis file here, this is enough.
    _parse_synthesis_or_ignore($urpm, $medium);

    1;
}

sub _parse_synthesis {
    my ($urpm, $medium, $synthesis_file, $o_callback) = @_;

    -e $synthesis_file or return;

    $urpm->{log}(N("examining synthesis file [%s]", $synthesis_file));
    ($medium->{start}, $medium->{end}) = 
      $urpm->parse_synthesis($synthesis_file, $o_callback ? (callback => $o_callback) : @{[]});
}

sub _parse_synthesis_or_ignore {
    my ($urpm, $medium, $o_callback) = @_;

    _parse_synthesis($urpm, $medium, any_synthesis($urpm, $medium), $o_callback) or
      _ignore_medium_on_parse_error($urpm, $medium);
}

sub is_valid_medium {
    my ($medium) = @_;
    defined $medium->{start} && defined $medium->{end};
}

sub _ignore_medium_on_parse_error {
    my ($urpm, $medium) = @_;

    $urpm->{error}(N("problem reading synthesis file of medium \"%s\"", $medium->{name}));
    $medium->{ignore} = 1;
}

sub _get_list_or_pubkey__local {
    my ($urpm, $medium, $name) = @_;

    my $path = _synthesis_dir($medium) . "/$name" . _synthesis_suffix($medium);
    -e $path or $path = file_from_local_url($medium->{url}) . "/media_info/$name";
    if (-e $path) {
	$urpm->{log}(N("copying [%s] for medium \"%s\"...", $path, $medium->{name}));
	copy_and_own($path, "$urpm->{cachedir}/partial/$name")
	  or $urpm->{error}(N("...copying failed")), return;
    }
    1;
}

sub _get_list_or_pubkey__remote {
    my ($urpm, $medium, $name) = @_;

    my $found;
    if (_synthesis_suffix($medium)) {
	my $local_name = $name . _synthesis_suffix($medium);

	if (urpm::download::sync($urpm, $medium, [_synthesis_dir($medium) . "/$local_name"], 
				 quiet => 1)) {
	    rename("$urpm->{cachedir}/partial/$local_name", "$urpm->{cachedir}/partial/$name");
	    $found = 1;
	}
    }
    if (!$found) {
	urpm::download::sync($urpm, $medium, [_synthesis_dir($medium) .  "/$name"], quiet => 1)
	    or unlink "$urpm->{cachedir}/partial/$name";
    }
}

sub get_descriptions_local {
    my ($urpm, $medium) = @_;

    unlink statedir_descriptions($urpm, $medium);

    my $dir = file_from_local_url($medium->{url});
    my $description_file = "$dir/media_info/descriptions"; #- new default location
    -e $description_file or $description_file = "$dir/../descriptions";
    -e $description_file or return;

    $urpm->{log}(N("copying description file of \"%s\"...", $medium->{name}));
    if (copy_and_own($description_file, statedir_descriptions($urpm, $medium))) {
	$urpm->{log}(N("...copying done"));
    } else {
	$urpm->{error}(N("...copying failed"));
	$medium->{ignore} = 1;
    }
}
sub get_descriptions_remote {
    my ($urpm, $medium) = @_;

    unlink "$urpm->{cachedir}/partial/descriptions";

    if (-e statedir_descriptions($urpm, $medium)) {
	urpm::util::move(statedir_descriptions($urpm, $medium), "$urpm->{cachedir}/partial/descriptions");
    }
    urpm::download::sync($urpm, $medium, [ reduce_pathname("$medium->{url}/media_info/descriptions") ], quiet => 1) 
	or #- try older location
	  urpm::download::sync($urpm, $medium, [ reduce_pathname("$medium->{url}/../descriptions") ], quiet => 1);

    if (-e "$urpm->{cachedir}/partial/descriptions") {
	urpm::util::move("$urpm->{cachedir}/partial/descriptions", statedir_descriptions($urpm, $medium));
    }
}
sub get_synthesis__local {
    my ($urpm, $medium, $callback) = @_;

    my $f = cachedir_with_synthesis($urpm, $medium);
    unlink $f;
    $urpm->{log}(N("copying [%s] for medium \"%s\"...", _url_with_synthesis($medium), $medium->{name}));
    $callback and $callback->('copy', $medium->{name});
    if (copy_and_own(_url_with_synthesis($medium), $f)) {
	$callback and $callback->('done', $medium->{name});
	$urpm->{log}(N("...copying done"));
	if (file_size($f) < 20) {
	    $urpm->{error}(N("copy of [%s] failed (file is suspiciously small)", $f));
	    0;
	} else {
	    1;
	}
    } else {
	$callback and $callback->('failed', $medium->{name});
	#- force error, reported afterwards
	unlink $f;
	0;
    }
}
sub get_synthesis__remote {
    my ($urpm, $medium, $callback, $quiet) = @_;

    if (urpm::download::sync($urpm, $medium, [ _url_with_synthesis($medium) ],
			     quiet => $quiet, callback => $callback) &&
			       file_size(cachedir_with_synthesis($urpm, $medium)) >= 20) {
	1;
    } else {
	chomp(my $err = $@);
	$urpm->{error}(N("...retrieving failed: %s", $err));
	0;
    }
}

#- check copied/downloaded file has right signature.
sub check_synthesis_md5sum {
    my ($urpm, $medium) = @_;

    my $wanted_md5sum = urpm::md5sum::from_MD5SUM__or_warn($urpm, "$urpm->{cachedir}/partial/MD5SUM", 'synthesis.hdlist.cz');
    if ($wanted_md5sum) {
	$urpm->{log}(N("computing md5sum of retrieved source synthesis"));
	urpm::md5sum::compute(cachedir_with_synthesis($urpm, $medium)) eq $wanted_md5sum or
	    $urpm->{error}(N("copy of [%s] failed (md5sum mismatch)", _url_with_synthesis($medium))), return;
    }
    1;
}

sub _call_genhdlist2 {
    my ($urpm, $medium) = @_;

    !$medium->{with_synthesis} or $urpm->{fatal}(1, 'with_synthesis not handled with --probe-rpms');

    my $dir = file_from_local_url($medium->{url});

    system('genhdlist2', 
	   $urpm->{debug} ? '--verbose' : (), '--no-hdlist',
	   '--media_info-dir', "$urpm->{cachedir}/partial", $dir) == 0 
      or $urpm->{error}(N("genhdlist2 failed on %s", $dir)), return;

    1;
}

sub _is_statedir_MD5SUM_uptodate {
    my ($urpm, $medium, $new_MD5SUM) = @_;

    my $current_MD5SUM = statedir_MD5SUM($urpm, $medium);

    $urpm->{log}(N("comparing %s and %s", $new_MD5SUM, $current_MD5SUM));

    cat_($new_MD5SUM) eq cat_($current_MD5SUM);
}

#- options: callback, force, nomd5sum, nopubkey, probe_with
sub _update_medium__parse_if_unmodified__local {
    my ($urpm, $medium, $options) = @_;

    my $dir = file_from_local_url($medium->{url});

    if (!-d $dir) {
	#- the directory given does not exist and may be accessible
	#- by mounting some other directory. Try to figure it out and mount
	#- everything that might be necessary.
	urpm::removable::try_mounting($urpm,
	    $options->{probe_with} ne 'rpms' && _synthesis_dir($medium)
	      ? _synthesis_dir($medium) : $dir,
	    #- in case of an iso image, pass its name
	    urpm::removable::is_iso($medium->{removable}) && $medium->{removable},
	) or $urpm->{error}(N("unable to access medium \"%s\",
this could happen if you mounted manually the directory when creating the medium.", $medium->{name})), return;
    }

    #- try to probe for possible with_synthesis parameter, unless
    #- it is already defined (and valid).
    if (!_synthesis_dir($medium) && $options->{probe_with} ne 'rpms') {
	_probe_with_try_list($urpm, $medium, sub {
	    my ($url) = @_;
	    -e $url or return;
	    if (file_size($url) >= 20) {
		1;
	    } else {
		$urpm->{error}(N("invalid hdlist file %s for medium \"%s\"", $url, $medium->{name}));
		0;
	    }
	});
    }

    if ($medium->{virtual}) {
	#- syncing a virtual medium is very simple, just try to read the file in order to
	#- determine its type, once a with_synthesis has been found (but is mandatory).
	_parse_synthesis_or_ignore($urpm, $medium);
	1;
    } elsif ($options->{probe_with} eq 'rpms' || !_synthesis_dir($medium)) {
	_call_genhdlist2($urpm, $medium) or return '';
	1;
    } elsif (_synthesis_dir($medium)) {
	my $new_MD5SUM = _synthesis_dir($medium) . '/MD5SUM';
	unlink "$urpm->{cachedir}/partial/MD5SUM";

	if (!$options->{nomd5sum} && file_size($new_MD5SUM) > 32) {	
	    if (!$options->{force} && _is_statedir_MD5SUM_uptodate($urpm, $medium, $new_MD5SUM)) {
		_read_existing_synthesis($urpm, $medium)
		  and return 'unmodified';
	    }

	    $urpm->{log}(N("copying MD5SUM file of \"%s\"...", $medium->{name}));
	    copy_and_own($new_MD5SUM, "$urpm->{cachedir}/partial/MD5SUM");
	}

	my $ok = get_synthesis__local($urpm, $medium, $options->{callback});
	$ok &&= !$options->{force} || check_synthesis_md5sum($urpm, $medium);
	
	if ($ok) {
	    1;
	} elsif ($urpm->{options}{'build-hdlist-on-error'}) {
	    #- if copying synthesis has failed, try to build it directly.
	    _call_genhdlist2($urpm, $medium) or return '';
	    1;
	} else {
	    _ignore_medium_on_parse_error($urpm, $medium);
	    '';
	}
    }
}

#- options: callback, force, nomd5sum, nopubkey, probe_with, quiet
sub _update_medium__parse_if_unmodified__remote {
    my ($urpm, $medium, $options) = @_;

    #- examine if a distant MD5SUM file is available.
    #- this will only be done if $with_synthesis is not empty in order to use
    #- an existing synthesis file, and to check if download was good.
    #- if no MD5SUM is available, do it as before...
    if (_synthesis_dir($medium)) {
	#- we can assume at this point a basename is existing, but it needs
	#- to be checked for being valid, nothing can be deduced if no MD5SUM
	#- file is present.

	my $new_MD5SUM = "$urpm->{cachedir}/partial/MD5SUM";
	unlink $new_MD5SUM;
	if (!$options->{nomd5sum} && 
	      urpm::download::sync($urpm, $medium, 
				   [ reduce_pathname(_synthesis_dir($medium) . '/MD5SUM') ],
				   quiet => 1) && file_size($new_MD5SUM) > 32) {
	    if ($options->{force} < 2 && _is_statedir_MD5SUM_uptodate($urpm, $medium, $new_MD5SUM)) {
		_read_existing_synthesis($urpm, $medium)
		  and return 'unmodified';
	    }
	}
    }

    #- try to probe for possible with_synthesis parameter, unless
    #- it is already defined (and valid).
    $urpm->{log}(N("retrieving source synthesis of \"%s\"...", $medium->{name}));
    $options->{callback} and $options->{callback}('retrieve', $medium->{name});
    my $error = sub {
	my ($msg) = @_;
	$urpm->{error}($msg);
	unlink cachedir_with_synthesis($urpm, $medium);
	$options->{callback} and $options->{callback}('failed', $medium->{name});
    };
    if (!_synthesis_dir($medium)) {
	my $err;
	_probe_with_try_list($urpm, $medium, sub {
	    my ($url) = @_;
	    my $f = "$urpm->{cachedir}/partial/" . basename($url);
	    $options->{force} and unlink $f;
	    if (urpm::download::sync($urpm, $medium, [ $url ],
				     quiet => $options->{quiet}, callback => $options->{callback}) && file_size($f) >= 20) {
		$urpm->{log}(N("found probed synthesis as %s", $url));
		1;
	    } else {
		chomp($err = $@);
		0;
	    }
	}) or do {
	    $error->(N("no synthesis file found for medium \"%s\"", $medium->{name}));
	    $urpm->{error}(N("...retrieving failed: %s", $err));
	    return;
	};
    } else {
	if ($options->{force}) {
	    unlink cachedir_with_synthesis($urpm, $medium);
	} else {
	    #- for rsync, try to sync (copy if needed) local copy after restored the previous one.
	    my $previous_synthesis = statedir_synthesis($urpm, $medium);
	    if (-e $previous_synthesis && urpm::protocol_from_url($medium->{url}) eq 'rsync') {
		copy_and_own(
		    $previous_synthesis,
		    cachedir_with_synthesis($urpm, $medium),
		) or $error->(N("...copying failed")), return;
	    }
	}
	my $ok = get_synthesis__remote($urpm, $medium, $options->{callback}, $options->{quiet});
	$ok &&= !$options->{force} || check_synthesis_md5sum($urpm, $medium);

	$options->{callback} and $options->{callback}('done', $medium->{name});

	if (!$ok) {
	    _ignore_medium_on_parse_error($urpm, $medium);
	    return;
	}
    }
    1;
}

sub _get_pubkey_and_descriptions {
    my ($urpm, $medium, $nopubkey) = @_;

    my $local = file_from_local_url($medium->{url});

    ($local ? \&get_descriptions_local : \&get_descriptions_remote)->($urpm, $medium);

    #- examine if a pubkey file is available.
    if (!$nopubkey && !$medium->{'key-ids'}) {
	($local ? \&_get_list_or_pubkey__local : \&_get_list_or_pubkey__remote)->($urpm, $medium, 'pubkey');
    }
}

sub _read_cachedir_pubkey {
    my ($urpm, $medium, $b_wait_lock) = @_;
    -s "$urpm->{cachedir}/partial/pubkey" or return;

    $urpm->{log}(N("examining pubkey file of \"%s\"...", $medium->{name}));

    my $_rpm_lock = urpm::lock::rpm_db($urpm, 'exclusive', wait => $b_wait_lock);
    my $db = urpm::db_open_or_die($urpm, $urpm->{root}, 'rw');

    my %key_ids;
    URPM::import_needed_pubkeys_from_file($db,
	"$urpm->{cachedir}/partial/pubkey",
	sub {
	    my ($id, $imported) = @_;
	    if ($id) {
		$key_ids{$id} = undef;
		$imported and $urpm->{log}(N("...imported key %s from pubkey file of \"%s\"",
					     $id, $medium->{name}));
		$imported or $urpm->{debug}("pubkey $id already imported") if $urpm->{debug};
	    } else {
		$urpm->{error}(N("unable to import pubkey file of \"%s\"", $medium->{name}));
	    }
	});
    if (keys(%key_ids)) {
	$medium->{'key-ids'} = join(',', keys %key_ids);
    }

    unlink "$urpm->{cachedir}/partial/pubkey";
}

#- options: callback, force, nomd5sum, probe_with, quiet
#- (from _update_medium__parse_if_unmodified__local and _update_medium__parse_if_unmodified__remote)
sub _update_medium_first_pass {
    my ($urpm, $medium, %options) = @_;

    unless ($medium->{modified}) {
	_parse_synthesis_or_ignore($urpm, $medium);
	return 'unmodified';
    }

    #- always delete a remaining list file or pubkey file in cache.
    foreach (qw(list pubkey)) {
	unlink "$urpm->{cachedir}/partial/$_";
    }

    #- check for a reconfig.urpmi file (if not already reconfigured)
    if (!$medium->{noreconfigure}) {
	may_reconfig_urpmi($urpm, $medium);
    }

    {
	my $rc = 
	  file_from_local_url($medium->{url})
	    ? _update_medium__parse_if_unmodified__local($urpm, $medium, \%options)
	    : _update_medium__parse_if_unmodified__remote($urpm, $medium, \%options);

	if (!$rc || $rc eq 'unmodified') {
	    return $rc;
	}
    }

    if (!$medium->{virtual}) {
	if (file_size(cachedir_with_synthesis($urpm, $medium)) < 20) {
	    $urpm->{error}(N("no synthesis file found for medium \"%s\"", $medium->{name}));
	    return;
	}

	    $options{callback} and $options{callback}('parse', $medium->{name});

	    if (_parse_synthesis($urpm, $medium, cachedir_with_synthesis($urpm, $medium))) {
		$options{callback} && $options{callback}('done', $medium->{name});
	    } else {
		$urpm->{error}(N("unable to parse synthesis file of \"%s\"", $medium->{name}));
		$options{callback} and $options{callback}('failed', $medium->{name});

		#- we have to read back the current synthesis file unmodified.
		_parse_synthesis_or_ignore($urpm, $medium);

		return;
	    }

	    if (-e statedir_synthesis($urpm, $medium)) {
		$urpm->{info}(N("updated medium \"%s\"", $medium->{name}));
	    }


	    #- use new files

	    unlink statedir_synthesis($urpm, $medium);
	    urpm::util::move(cachedir_with_synthesis($urpm, $medium),
			     statedir_synthesis($urpm, $medium));

	    unlink statedir_MD5SUM($urpm, $medium);
	    if (!$medium->{with_synthesis}) { # no MD5SUM when using with_synthesis, urpmi.update will update everytime!
		urpm::util::move("$urpm->{cachedir}/partial/MD5SUM",
				 statedir_MD5SUM($urpm, $medium)) if -e "$urpm->{cachedir}/partial/MD5SUM";
	    }

    }
    #- make sure to rebuild base files and clear medium modified state.
    $medium->{modified} = 0;
    $medium->{really_modified} = 1;

    1;
}

sub _update_medium_first_pass_failed {
    my ($urpm, $medium) = @_;

    !$medium->{virtual} or return;

    #- an error has occured for updating the medium, we have to remove temporary files.
    unlink(glob("$urpm->{cachedir}/partial/*"));
}

sub _update_media__handle_some_flags {
    my ($urpm, $forcekey, $all) = @_;

    foreach my $medium (grep { !$_->{ignore} } @{$urpm->{media}}) {
	$forcekey and delete $medium->{'key-ids'};

	if ($medium->{static}) {
	    #- don't ever update static media
	    $medium->{modified} = 0;
	} elsif ($all) {
	    #- if we're rebuilding all media, mark them as modified (except removable ones)
	    $medium->{modified} ||= $medium->{url} !~ m!^removable!;
	}
    }
}

#- Update the urpmi database w.r.t. the current configuration.
#- Takes care of modifications, and tries some tricks to bypass
#- the recomputation of base files.
#- Recognized options :
#-   all         : all medias are being rebuilt
#-   callback    : UI callback
#-   forcekey    : force retrieval of pubkey
#-   force       : try to force rebuilding base files
#-   noclean     : keep old files in the header cache directory
#-   nomd5sum    : don't verify MD5SUM of retrieved files
#-   nopubkey    : don't use rpm pubkeys
#-   probe_with  : probe synthesis or rpms
#-   quiet       : download synthesis quietly
#-   wait_lock   : block until lock can be acquired
sub update_media {
    my ($urpm, %options) = @_;

    $urpm->{media} or return; # verify that configuration has been read

    $options{nopubkey} ||= $urpm->{options}{nopubkey};

    #- examine each medium to see if one of them needs to be updated.
    #- if this is the case and if not forced, try to use a pre-calculated
    #- synthesis file, else build it from rpm files.
    clean($urpm);

    _update_media__handle_some_flags($urpm, $options{forcekey}, $options{all});

    my %updates_result;
    foreach my $medium (grep { !$_->{ignore} } @{$urpm->{media}}) {
	my $rc = _update_medium_first_pass($urpm, $medium, %options);
	$updates_result{$rc || 'error'}++;
	$rc or _update_medium_first_pass_failed($urpm, $medium);
    }

    $urpm->{debug} and $urpm->{debug}('update_medium: ' . join(' ', map { "$_=$updates_result{$_}" } keys %updates_result));

    if ($updates_result{1} == 0) {
	#- only errors/unmodified, leave now
	#- (this ensures buggy added medium is not added to urpmi.cfg)
	return $updates_result{error} == 0;
    }

    foreach my $medium (grep { !$_->{ignore} } @{$urpm->{media}}) {
	if ($medium->{really_modified}) {
	    _get_pubkey_and_descriptions($urpm, $medium, $options{nopubkey});
	    _read_cachedir_pubkey($urpm, $medium, $options{wait_lock});
	    generate_medium_names($urpm, $medium);
	}
    }

    if ($urpm->{modified}) {
	if ($options{noclean}) {
	    #- clean headers cache directory to remove everything that is no longer
	    #- useful according to the depslist.
	    urpm::remove_obsolete_headers_in_cache($urpm);
	}
	#- write config files in any case
	write_config($urpm);
	urpm::download::dump_proxy_config();
    }

    $updates_result{error} == 0;
}

#- clean params and depslist computation zone.
sub clean {
    my ($urpm) = @_;

    $urpm->{depslist} = [];
    $urpm->{provides} = {};

    foreach (@{$urpm->{media} || []}) {
	delete $_->{start};
	delete $_->{end};
    }
}

1;