package urpm::sys;

# $Id$

use strict;
use warnings;
use urpm::util;
use urpm::msg;
use POSIX ();

(our $VERSION) = q($Revision$) =~ /(\d+)/;


#- get the list of packages that should not be upgraded or installed,
#- typically from the inst.list or skip.list files.
sub get_packages_list {
    my ($file, $o_extra) = @_;
    my @l = split(/,/, $o_extra || '');
    if ($file && open(my $f, '<', $file)) {
	push @l, <$f>;
    }
    [ grep { $_ } map {
	chomp; s/#.*$//; s/^\s*//; s/\s*$//;
	$_;
    } @l ];
}

sub _read_fstab_or_mtab {
    my ($file) = @_;

    my @l;
    foreach (cat_($file)) {
	next if /^\s*#/;
	my ($device, $mntpoint, $fstype, $_options) = m!^\s*(\S+)\s+(/\S+)\s+(\S+)\s+(\S+)!
	    or next;
	$mntpoint =~ s,/+,/,g; $mntpoint =~ s,/$,,;
	push @l, { mntpoint => $mntpoint, device => $device, fs => $fstype };
    }
    @l;
}

#- find used mount point from a pathname, use a optional mode to allow
#- filtering according the next operation (mount or umount).
sub find_mntpoints {
    my ($dir, $infos) = @_;

    #- read /etc/fstab and check for existing mount point.
    foreach (_read_fstab_or_mtab("/etc/fstab")) {
	$infos->{$_->{mntpoint}} = { mounted => 0, %$_ };
    }
    foreach (_read_fstab_or_mtab("/etc/mtab")) {
	$infos->{$_->{mntpoint}} = { mounted => 1, %$_ };
    }

    my (@mntpoints);
    #- try to follow symlink, too complex symlink graph may not be seen.
    #- check the possible mount point.
    my @paths = split '/', $dir;
    my $pdir = '';
    while (@paths) {
	my $path = shift @paths;
	length($path) or next;
	$pdir .= "/$path";
	$pdir =~ s,/+,/,g; $pdir =~ s,/$,,;
	if (exists($infos->{$pdir})) {
	    push @mntpoints, $pdir;
	    #- following symlinks may be useless or dangerous for supermounted devices.
	    #- this means it is assumed no symlink inside a removable device
	    #- will go outside the device itself (or at least will go into
	    #- regular already mounted device like /).
	    #- for simplification we refuse also any other device and stop here.
	    last;
	} elsif (-l $pdir) {
	    while (my $v = readlink $pdir) {
		if ($pdir =~ m|^/|) {
		    $pdir = $v;
		} else {
		    while ($v =~ s!^\.\./!!) {
			$pdir =~ s!/[^/]+/*$!!;
		    }
		    $pdir .= "/$v";
		}
	    }
	    unshift @paths, split '/', $pdir;
	    $pdir = '';
	}
    }
    @mntpoints;
}

sub clean_rpmdb_shared_regions {
    my ($prefix) = @_;
    unlink glob("$prefix/var/lib/rpm/__db.*");
}

sub proc_mounts() {
    my @l = cat_('/proc/mounts') or warn "Can't read /proc/mounts: $!\n";
    @l;
}

#- returns the first unused loop device, or an empty string if none is found.
sub first_free_loopdev () {
    my %loopdevs = map { $_ => 1 } grep { ! -d $_ } glob('/dev/loop*');
    foreach (proc_mounts()) {
	(our $dev) = split ' ';
	delete $loopdevs{$dev} if $dev =~ m!^/dev/loop!;
    }
    my @l = keys %loopdevs;
    @l ? $l[0] : '';
}

sub trim_until_d {
    my ($dir) = @_;
    foreach (proc_mounts()) {
	#- fail if an iso is already mounted
	m!^/dev/loop! and return $dir;
    }
    while ($dir && !-d $dir) { $dir =~ s,/[^/]*$,, }
    $dir;
}

#- checks if the main filesystems are writeable for urpmi to install files in
sub check_fs_writable () {
    foreach (proc_mounts()) {
	(undef, our $mountpoint, undef, my $opts) = split ' ';
	if ($opts =~ /(?:^|,)ro(?:,|$)/ && $mountpoint =~ m!^(/|/usr|/s?bin)\z!) {
	    return 0;
	}
    }
    1;
}

#- create a plain rpm from an installed rpm and a delta rpm (in the current directory)
#- returns the new rpm filename in case of success
#- params :
#-	$deltarpm : full pathname of the deltarpm
#-	$o_dir : directory where to put the produced rpm (optional)
#-	$o_pkg : URPM::Package object corresponding to the deltarpm (optional)
our $APPLYDELTARPM = '/usr/bin/applydeltarpm';
sub apply_delta_rpm {
    my ($deltarpm, $o_dir, $o_pkg) = @_;
    -x $APPLYDELTARPM or return 0;
    -e $deltarpm or return 0;
    my $rpm;
    if ($o_pkg) {
	require URPM; #- help perl_checker
	$rpm = $o_pkg->name . '-' . $o_pkg->version . '-' . $o_pkg->release . '.' . $o_pkg->arch . '.rpm';
    } else {
	$rpm = `rpm -qp --qf '%{name}-%{version}-%{release}.%{arch}.rpm' '$deltarpm'`;
    }
    $rpm or return 0;
    $rpm = $o_dir . '/' . $rpm;
    unlink $rpm;
    system($APPLYDELTARPM, $deltarpm, $rpm);
    -e $rpm ? $rpm : '';
}

our $tempdir_template = '/tmp/urpm.XXXXXX';
sub mktempdir() {
    my $tmpdir;
    eval { require File::Temp };
    if ($@) {
	#- fall back to external command (File::Temp not in perl-base)
	$tmpdir = `mktemp -d $tempdir_template`;
	chomp $tmpdir;
    } else {
	$tmpdir = File::Temp::tempdir($tempdir_template);
    }
    return $tmpdir;
}

# temporary hack used by urpmi when restarting itself.
sub fix_fd_leak() {
    opendir my $dirh, "/proc/$$/fd" or return undef;
    my @fds = grep { /^(\d+)$/ && $1 > 2 } readdir $dirh;
    closedir $dirh;
    foreach (@fds) {
	my $link = readlink("/proc/$$/fd/$_");
	$link or next;
	next if $link =~ m!^/(usr|dev)/! || $link !~ m!^/!;
	POSIX::close($_);
    }
}

sub clean_dir {
    my ($dir) = @_;

    require File::Path;
    File::Path::rmtree([$dir]);
    mkdir $dir, 0755;
}

sub syserror { 
    my ($urpm, $msg, $info) = @_;
    $urpm->{error}("$msg [$info] [$!]");
}

sub open_safe {
    my ($urpm, $sense, $filename) = @_;
    open my $f, $sense, $filename
	or syserror($urpm, $sense eq '>' ? N("Can't write file") : N("Can't open file"), $filename), return undef;
    return $f;
}

sub opendir_safe {
    my ($urpm, $dirname) = @_;
    opendir my $d, $dirname
	or syserror($urpm, "Can't open directory", $dirname), return undef;
    return $d;
}

sub move_or_die {
    my ($urpm, $file, $dest) = @_;
    urpm::util::move($file, $dest) or $urpm->{fatal}(1, N("Can't move file %s to %s", $file, $dest));
}

1;
__END__

=head1 NAME

urpm::sys - OS-related routines for urpmi

=head1 SYNOPSIS

=head1 DESCRIPTION

=head1 COPYRIGHT

Copyright (C) 2005 MandrakeSoft SA

Copyright (C) 2005 Mandriva SA

=cut