package urpm::sys;

# $Id$

use strict;
use warnings;
use POSIX ();

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

#- 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, $infos) = @_;
    my (%fstab, @mntpoints);
    local ($_);
    #- read /etc/fstab and check for existing mount point.
    open my $f, "/etc/fstab" or return ();
    while (<$f>) {
	next if /^\s*#/;
	my ($device, $mntpoint, $fstype, $options) = m!^\s*(\S+)\s+(/\S+)\s+(\S+)\s+(\S+)!
	    or next;
	$mntpoint =~ s,/+,/,g; $mntpoint =~ s,/$,,;
	$fstab{$mntpoint} =  0;
	if (ref($infos)) {
	    if ($fstype eq 'supermount') {
		$options =~ /^(?:.*[\s,])?dev=([^\s,]+)/ and $infos->{$mntpoint} = {
		    mounted => 0,
		    device => $1,
		    fs => $fstype,
		    supermount => 1,
		};
	    } else {
		$infos->{$mntpoint} = { mounted => 0, device => $device, fs => $fstype };
	    }
	}
    }
    close $f;
    open $f, "/etc/mtab" or return ();
    while (<$f>) {
	my ($device, $mntpoint, $fstype, $options) = m!^\s*(\S+)\s+(/\S+)\s+(\S+)\s+(\S+)!
	    or next;
	$mntpoint =~ s,/+,/,g; $mntpoint =~ s,/$,,;
	$fstab{$mntpoint} = 1;
	if (ref($infos)) {
	    if ($fstype eq 'supermount') {
		$options =~ /^(?:.*[\s,])?dev=([^\s,]+)/ and $infos->{$mntpoint} = {
		    mounted => 1,
		    device => $1,
		    fs => $fstype,
		    supermount => 1,
		};
	    } else {
		$infos->{$mntpoint} = { mounted => 1, device => $device, fs => $fstype };
	    }
	}
    }
    close $f;
    #- try to follow symlink, too complex symlink graph may not be seen.
    #- check the possible mount point.
    my @paths = split '/', $dir;
    my $pdir = '';
    while (defined ($_ = shift @paths)) {
	length($_) or next;
	$pdir .= "/$_";
	$pdir =~ s,/+,/,g; $pdir =~ s,/$,,;
	if (exists($fstab{$pdir})) {
	    ref($infos) and push @mntpoints, $pdir;
	    $infos eq 'mount' && ! $fstab{$pdir} and push @mntpoints, $pdir;
	    $infos eq 'umount' && $fstab{$pdir} and unshift @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 =~ m|^\.\./(.*)|) {
			$v = $1;
			$pdir =~ s|^(.*)/[^/]+/*|$1|;
		    }
		    $pdir .= "/$v";
		}
	    }
	    unshift @paths, split '/', $pdir;
	    $pdir = '';
	}
    }
    @mntpoints;
}

#- returns the first unused loop device, or an empty string if none is found.
sub first_free_loopdev () {
    open my $mounts, '/proc/mounts' or do { warn "Can't read /proc/mounts: $!\n"; return 1 };
    my %loopdevs = map { $_ => 1 } grep { ! -d $_ } glob('/dev/loop*');
    local *_;
    while (<$mounts>) {
	(our $dev) = split ' ';
	delete $loopdevs{$dev} if $dev =~ m!^/dev/loop!;
    }
    close $mounts;
    my @l = keys %loopdevs;
    @l ? $l[0] : '';
}

sub trim_until_d {
    my ($dir) = @_;
    open my $mounts, '/proc/mounts' or do { warn "Can't read /proc/mounts: $!\n"; return $dir };
    local $_;
    while (<$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 () {
    open my $mounts, '/proc/mounts' or do { warn "Can't read /proc/mounts: $!\n"; return 1 };
    local *_;
    while (<$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) {
	$rpm = $o_pkg->name . '-' . $o_pkg->version . '-' . $o_pkg->release . '.' . $o_pkg->arch . '.rpm';
    } else {
	$rpm = qx(rpm -qp --qf '%{name}-%{version}-%{release}.%{arch}.rpm' '$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 = qx(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/$$/fd" or return undef;
    my @fds = grep { /^(\d+)$/ && $1 > 2 } readdir $dirh;
    closedir $dirh;
    for (@fds) {
	my $link = readlink("/proc/$$/fd/$_");
	$link or next;
	next if $link =~ m!^/(usr|dev)/! || $link !~ m!^/!;
	POSIX::close($_);
    }
}

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