utils/pxelinux-options - platform/external/syslinux - Git at Google

 #!/usr/bin/perl
 #
 # Set PXELINUX hard-coded options
 #

 use Socket;			# For gethostbyname
 use Fcntl;
 use bytes;

 %option_names = (
       6 => 'domain-name-servers',
      15 => 'domain-name',
      54 => 'next-server',
     209 => 'config-file',
     210 => 'path-prefix',
     211 => 'reboottime'
     );

 @fmt_oneip   = ("ip-address", \&parse_oneip, \&show_ip);
 @fmt_multiip = ("ip-address-list", \&parse_multiip, \&show_ip);
 @fmt_string  = ("string", \&parse_string, \&show_string);
 @fmt_uint32  = ("uint32", \&parse_uint32, \&show_uint32);

 %option_format = (
       6 => \@fmt_multiip,
      15 => \@fmt_string,
      54 => \@fmt_oneip,
      67 => \@fmt_string,
     209 => \@fmt_string,
     210 => \@fmt_string,
     211 => \@fmt_uint32
     );

 sub parse_oneip($)
 {
     my($s) = @_;
     my($name,$aliases,$addrtype,$length,@addrs) = gethostbyname($s);

     return ($addrtype == AF_INET) ? $addrs[0] : undef;
 }

 sub parse_multiip($)
 {
     my($l) = @_;
     my $s;
     my @a = ();
     my $addr;
     my $d = '';

     foreach $s (split(/,/, $l)) {
 	my($name,$aliases,$addrtype,$length,@addrs)
 	    = gethostbyname($s);
 	if ($addrtype == AF_INET) {
 	    foreach $addr (@addrs) {
 		$d .= $addr;
 	    }
 	}
     }

     return $d ne '' ? $d : undef;
 }

 sub show_ip($)
 {
     my($l) = @_;

     if (length($l) & 3) {
 	return undef;
     } else {
 	my @h = ();
 	my $i;

 	for ($i = 0; $i < length($l); $i += 4) {
 	    push(@h, inet_ntoa(substr($l, $i, 4)));
 	}

 	return join(',', @h);
     }
 }

 sub parse_string($)
 {
     return $_[0];
 }

 sub show_string($)
 {
     my($s) = @_;
     my $o, $i, $c;

     $o = "\'";
     for ($i = 0; $i < length($s); $i++) {
 	$c = substr($s, $i, 1);
 	if ($c eq "\'" || $c eq '!') {
 	    $o .= "\'\\$c\'";
 	} else {
 	    $o .= $c;
 	}
     }
     $o .= "\'";

     return $o;
 }

 sub parse_uint32($)
 {
     my($s) = @_;

     if ($s =~ /^[0-9]+$/) {
 	return pack("N", $s);
     } else {
 	return undef;
     }
 }

 sub show_uint32($)
 {
     my($l) = @_;

     if (length($l) == 4) {
 	return unpack("N", $l);
     } else {
 	return undef;
     }
 }

 sub parse_generic($)
 {
     my($s) = @_;

     if ($s =~ /^[0-9a-f]{1,2}(:[0-9a-f]{1,2})*$/) {
 	my $h;
 	my @b = ();

 	foreach $h (split(/\:/, $s)) {
 	    push(@b, hex $h);
 	}

 	return pack("C", @b);
     } else {
 	return undef;
     }
 }

 sub show_generic($)
 {
     my($l) = @_;
     my $i;
     my @h;

     for ($i = 0; $i < length($l); $i++) {
 	push(@h, sprintf("%02x", unpack("C", substr($l, $i, $1))));
     }

     return join(':', @h);
 }

 sub parse_option($$)
 {
     my($opt, $arg) = @_;
     my $v;

     if (defined($option_format{$opt})) {
 	$v = $option_format{$opt}[1]($arg);
 	return $v if (defined($v));
     }

     return parse_generic($arg);
 }

 sub show_option($$)
 {
     my($opt, $arg) = @_;
     my $v;

     if (defined($option_format{$opt})) {
 	$v = $option_format{$opt}[2]($arg);
 	return $v if (defined($v));
     }

     return show_generic($arg);
 }

 sub option_number($)
 {
     my($n) = @_;

     if (defined($option_rnames{$n})) {
 	return $option_rnames{$n};
     } elsif ($n =~ /^[0-9]+$/ && $n >= 1 && $n <= 254) {
 	return $n+0;
     } else {
 	return undef;
     }
 }

 sub read_optsets($)
 {
     my($file) = @_;
     my $data, $bdata, $adata;
     my $patch_start = (stat($file))[7];
     my $hdroffset = 0;		# 0 means non-deep-embedded
     my $bufsize = 0;
     my $junk;
     my %hdr;

     return undef unless (seek($file, 0, SEEK_SET));
     return undef unless (read($file, $data, 48) == 48);

     my($mzmagic, $junk, $magic, $len, $flags, $boff, $blen, $aoff, $alen)
 	= unpack("va[6]VVVVVVV", $data);

     if ($mzmagic == 0x5a4d) {
 	# It is an EFI file... search for the magic number
 	$hdroffset = 48;
 	my $magic = pack("VVVV", 0x2a171ead, 0x0600e65e,
 			 0x4025a4e4, 0x42388fc8);

 	while (1) {
 	    return undef unless (read($file, $data, 16) == 16);
 	    last if ($data eq $magic);

 	    $hdroffset += 16;
 	}

 	return undef unless (read($file, $data, 16) == 16);
 	($blen, $alen, $bufsize, $junk) = unpack("VVVV", $data);

 	$patch_start = $boff = $hdroffset + 32;
 	$aoff = $boff + $blen;

 	$hdr{'deep'} = 1;
 	$hdr{'bufsize'} = $bufsize;
 	$hdr{'hdroffset'} = $hdroffset;
     } else {
 	# It is a BIOS PXE file

 	return undef if ($magic != 0x2983c8ac);
 	return undef if ($len < 7*4);

 	$hdr{'deep'} = 0;
     }

     if ($blen == 0) {
 	$bdata = '';
     } else {
 	return undef unless (seek($file, $boff, SEEK_SET));
 	return undef unless (read($file, $bdata, $blen) == $blen);
 	$patch_start = $boff if ($boff < patch_start);
     }

     if ($alen == 0) {
 	$adata = '';
     } else {
 	return undef unless (seek($file, $aoff, SEEK_SET));
 	return undef unless (read($file, $adata, $alen) == $alen);
 	$patch_start = $aoff if ($aoff < $patch_start);
     }

     $hdr{'patch_start'} = $patch_start;

     return (\%hdr, $bdata, $adata);
 }

 sub write_optsets($$@)
 {
     my($file, $hdr, $bdata, $adata) = @_;
     my $boff = 0;
     my $aoff = 0;
     my $bufsize = 0;
     my $patch_start = $hdr->{'patch_start'};
     my $len;

     $bdata .= "\xff" unless ($bdata eq '');
     $adata .= "\xff" unless ($adata eq '');

     $len = length($bdata) + length($adata);

     if (defined($hdr->{'bufsize'})) {
 	return undef unless ($len <= $hdr->{'bufsize'});
     }

     return undef unless (seek($file, $patch_start, SEEK_SET));

     if (length($bdata)) {
 	$boff = $patch_start;
 	return undef unless (print $file $bdata);
 	$patch_start += length($bdata);
     }

     if (length($adata)) {
 	$aoff = $patch_start;
 	return undef unless (print $file $adata);
 	$patch_start += length($adata);
     }

     if ($hdr->{'deep'}) {
 	return undef unless (print $file "\0" x ($hdr->{'bufsize'} - $len));
 	return undef unless (seek($file, $hdr->{'hdroffset'} + 16, SEEK_SET));
 	my $hdr = pack("VV", length($bdata), length($adata));
 	return undef unless (print $file $hdr);
     } else {
 	my $hdr = pack("VVVV", $boff, length($bdata), $aoff, length($adata));

 	return undef unless (seek($file, 8+3*4, SEEK_SET));
 	return undef unless (print $file $hdr);

 	truncate($file, $patch_start);
     }

     return 1;
 }

 sub delete_option($$)
 {
     my ($num, $block) = @_;
     my $o, $l, $c, $x;

     $x = 0;
     while ($x < length($block)) {
 	($o, $l) = unpack("CC", substr($block, $x, 2));
 	if ($o == $num) {
 	    # Delete this option
 	    substr($block, $x, $l+2) = '';
 	} elsif ($o == 0) {
 	    # Delete a null option
 	    substr($block, $x, 1) = '';
 	} elsif ($o == 255) {
 	    # End marker - truncate block
 	    $block = substr($block, 0, $x);
 	    last;
 	} else {
 	    # Skip to the next option
 	    $x += $l+2;
 	}
     }

     return $block;
 }

 sub add_option($$$)
 {
     my ($num, $data, $block) = @_;

     $block = delete_option($num, $block);

     if (length($data) == 0) {
 	return $block;
     } elsif (length($data) > 255) {
 	die "$0: option $num has too much data (max 255 bytes)\n";
     } else {
 	return $block . pack("CC", $num, length($data)) . $data;
     }
 }

 sub list_options($$)
 {
     my($pfx, $data) = @_;
     my $x, $o, $l;

     while ($x < length($data)) {
 	($o, $l) = unpack("CC", substr($data, $x, 2));

 	if ($o == 0) {
 	    $x++;
 	} elsif ($o == 255) {
 	    last;
 	} else {
 	    my $odata = substr($data, $x+2, $l);
 	    last if (length($odata) != $l); # Incomplete option

 	    printf "%s%-20s %s\n", $pfx,
 		$option_names{$o} || sprintf("%d", $o),
 		show_option($o, $odata);

 	    $x += $l+2;
 	}
     }
 }

 sub usage()
 {
     my $i;

     print STDERR "Usage: $0 options pxelinux.0\n";
     print STDERR "Options:\n";
     print STDERR "--before option value   -b   Add an option before DHCP data\n";
     print STDERR "--after  option value   -a   Add an option after DHCP data\n";
     print STDERR "--delete option         -d   Delete an option\n";
     print STDERR "--list                  -l   List set options\n";
     print STDERR "--dry-run               -n   Don't modify the target file\n";
     print STDERR "--help                  -h   Display this help text\n";
     print STDERR "\n";
     print STDERR "The following DHCP options are currently recognized:\n";
     printf STDERR "%-23s %-3s  %s\n", 'Name', 'Num', 'Value Format';

     foreach $i (sort { $a <=> $b } keys(%option_names)) {
 	printf STDERR "%-23s %3d  %s\n",
 		$option_names{$i}, $i, $option_format{$i}[0];
     }
 }

 %option_rnames = ();
 foreach $opt (keys(%option_names)) {
     $option_rnames{$option_names{$opt}} = $opt;
 }

 %before   = ();
 %after    = ();
 @clear    = ();
 $usage    = 0;
 $err      = 0;
 $list     = 0;
 $no_write = 0;
 undef $file;

 while (defined($opt = shift(@ARGV))) {
     if ($opt !~ /^-/) {
 	if (defined($file)) {
 	    $err = $usage = 1;
 	    last;
 	}
 	$file = $opt;
     } elsif ($opt eq '-b' || $opt eq '--before') {
 	$oname = shift(@ARGV);
 	$odata = shift(@ARGV);

 	if (!defined($odata)) {
 	    $err = $usage = 1;
 	    last;
 	}

 	$onum = option_number($oname);
 	if (!defined($onum)) {
 	    print STDERR "$0: unknown option name: $oname\n";
 	    $err = 1;
 	    next;
 	}

 	$odata = parse_option($onum, $odata);
 	if (!defined($odata)) {
 	    print STDERR "$0: unable to parse data for option $oname\n";
 	    $err = 1;
 	    next;
 	}

 	delete $after{$onum};
 	$before{$onum} = $odata;
 	push(@clear, $onum);
     } elsif ($opt eq '-a' || $opt eq '--after') {
 	$oname = shift(@ARGV);
 	$odata = shift(@ARGV);

 	if (!defined($odata)) {
 	    $err = $usage = 1;
 	    last;
 	}

 	$onum = option_number($oname);
 	if (!defined($onum)) {
 	    print STDERR "$0: unknown option name: $oname\n";
 	    $err = 1;
 	    next;
 	}

 	$odata = parse_option($onum, $odata);
 	if (!defined($odata)) {
 	    print STDERR "$0: unable to parse data for option $oname\n";
 	    $err = 1;
 	    next;
 	}

 	delete $before{$onum};
 	$after{$onum} = $odata;
 	push(@clear, $onum);
     } elsif ($opt eq '-d' || $opt eq '--delete') {
 	$oname = shift(@ARGV);

 	if (!defined($oname)) {
 	    $err = $usage = 1;
 	    last;
 	}

 	$onum = option_number($oname);
 	if (!defined($onum)) {
 	    print STDERR "$0: unknown option name: $oname\n";
 	    $err = 1;
 	    next;
 	}

 	push(@clear, $onum);
 	delete $before{$onum};
 	delete $after{$onum};
     } elsif ($opt eq '-n' || $opt eq '--no-write' || $opt eq '--dry-run') {
 	$no_write = 1;
     } elsif ($opt eq '-l' || $opt eq '--list') {
 	$list = 1;
     } elsif ($opt eq '-h' || $opt eq '--help') {
 	$usage = 1;
     } else {
 	print STDERR "Invalid option: $opt\n";
 	$err = $usage = 1;
     }
 }

 if (!defined($file) && !$usage) {
     $err = $usage = 1;
 }
 if ($usage) {
     usage();
 }
 if ($err || $usage) {
     exit($err);
 }

 if (!scalar(@clear)) {
     $no_write = 1;		# No modifications requested
 }

 $mode = $no_write ? '<' : '+<';

 open(FILE, $mode, $file)
     or die "$0: cannot open: $file: $!\n";
 ($hdrinfo, @data) = read_optsets(\*FILE);
 if (!defined($hdrinfo)) {
     die "$0: $file: patch block not found or file corrupt\n";
 }

 foreach $o (@clear) {
     $data[0] = delete_option($o, $data[0]);
     $data[1] = delete_option($o, $data[1]);
 }
 foreach $o (keys(%before)) {
     $data[0] = add_option($o, $before{$o}, $data[0]);
 }
 foreach $o (keys(%after)) {
     $data[1] = add_option($o, $after{$o}, $data[1]);
 }

 if ($list) {
     list_options('-b ', $data[0]);
     list_options('-a ', $data[1]);
 }

 if (!$no_write) {
     if (!write_optsets(\*FILE, $hdrinfo, @data)) {
 	die "$0: $file: failed to write options: $!\n";
     }
 }

 close(FILE);
 exit 0;
	#!/usr/bin/perl
	#
	# Set PXELINUX hard-coded options
	#

	use Socket; # For gethostbyname
	use Fcntl;
	use bytes;

	%option_names = (
	6 => 'domain-name-servers',
	15 => 'domain-name',
	54 => 'next-server',
	209 => 'config-file',
	210 => 'path-prefix',
	211 => 'reboottime'
	);

	@fmt_oneip = ("ip-address", \&parse_oneip, \&show_ip);
	@fmt_multiip = ("ip-address-list", \&parse_multiip, \&show_ip);
	@fmt_string = ("string", \&parse_string, \&show_string);
	@fmt_uint32 = ("uint32", \&parse_uint32, \&show_uint32);

	%option_format = (
	6 => \@fmt_multiip,
	15 => \@fmt_string,
	54 => \@fmt_oneip,
	67 => \@fmt_string,
	209 => \@fmt_string,
	210 => \@fmt_string,
	211 => \@fmt_uint32
	);

	sub parse_oneip($)
	{
	my($s) = @_;
	my($name,$aliases,$addrtype,$length,@addrs) = gethostbyname($s);

	return ($addrtype == AF_INET) ? $addrs[0] : undef;
	}

	sub parse_multiip($)
	{
	my($l) = @_;
	my $s;
	my @a = ();
	my $addr;
	my $d = '';

	foreach $s (split(/,/, $l)) {
	my($name,$aliases,$addrtype,$length,@addrs)
	= gethostbyname($s);
	if ($addrtype == AF_INET) {
	foreach $addr (@addrs) {
	$d .= $addr;
	}
	}
	}

	return $d ne '' ? $d : undef;
	}

	sub show_ip($)
	{
	my($l) = @_;

	if (length($l) & 3) {
	return undef;
	} else {
	my @h = ();
	my $i;

	for ($i = 0; $i < length($l); $i += 4) {
	push(@h, inet_ntoa(substr($l, $i, 4)));
	}

	return join(',', @h);
	}
	}

	sub parse_string($)
	{
	return $_[0];
	}

	sub show_string($)
	{
	my($s) = @_;
	my $o, $i, $c;

	$o = "\'";
	for ($i = 0; $i < length($s); $i++) {
	$c = substr($s, $i, 1);
	if ($c eq "\'" \|\| $c eq '!') {
	$o .= "\'\\$c\'";
	} else {
	$o .= $c;
	}
	}
	$o .= "\'";

	return $o;
	}

	sub parse_uint32($)
	{
	my($s) = @_;

	if ($s =~ /^[0-9]+$/) {
	return pack("N", $s);
	} else {
	return undef;
	}
	}

	sub show_uint32($)
	{
	my($l) = @_;

	if (length($l) == 4) {
	return unpack("N", $l);
	} else {
	return undef;
	}
	}

	sub parse_generic($)
	{
	my($s) = @_;

	if ($s =~ /^[0-9a-f]{1,2}(:[0-9a-f]{1,2})*$/) {
	my $h;
	my @b = ();

	foreach $h (split(/\:/, $s)) {
	push(@b, hex $h);
	}

	return pack("C", @b);
	} else {
	return undef;
	}
	}

	sub show_generic($)
	{
	my($l) = @_;
	my $i;
	my @h;

	for ($i = 0; $i < length($l); $i++) {
	push(@h, sprintf("%02x", unpack("C", substr($l, $i, $1))));
	}

	return join(':', @h);
	}

	sub parse_option($$)
	{
	my($opt, $arg) = @_;
	my $v;

	if (defined($option_format{$opt})) {
	$v = $option_format{$opt}[1]($arg);
	return $v if (defined($v));
	}

	return parse_generic($arg);
	}

	sub show_option($$)
	{
	my($opt, $arg) = @_;
	my $v;

	if (defined($option_format{$opt})) {
	$v = $option_format{$opt}[2]($arg);
	return $v if (defined($v));
	}

	return show_generic($arg);
	}

	sub option_number($)
	{
	my($n) = @_;

	if (defined($option_rnames{$n})) {
	return $option_rnames{$n};
	} elsif ($n =~ /^[0-9]+$/ && $n >= 1 && $n <= 254) {
	return $n+0;
	} else {
	return undef;
	}
	}

	sub read_optsets($)
	{
	my($file) = @_;
	my $data, $bdata, $adata;
	my $patch_start = (stat($file))[7];
	my $hdroffset = 0; # 0 means non-deep-embedded
	my $bufsize = 0;
	my $junk;
	my %hdr;

	return undef unless (seek($file, 0, SEEK_SET));
	return undef unless (read($file, $data, 48) == 48);

	my($mzmagic, $junk, $magic, $len, $flags, $boff, $blen, $aoff, $alen)
	= unpack("va[6]VVVVVVV", $data);

	if ($mzmagic == 0x5a4d) {
	# It is an EFI file... search for the magic number
	$hdroffset = 48;
	my $magic = pack("VVVV", 0x2a171ead, 0x0600e65e,
	0x4025a4e4, 0x42388fc8);

	while (1) {
	return undef unless (read($file, $data, 16) == 16);
	last if ($data eq $magic);

	$hdroffset += 16;
	}

	return undef unless (read($file, $data, 16) == 16);
	($blen, $alen, $bufsize, $junk) = unpack("VVVV", $data);

	$patch_start = $boff = $hdroffset + 32;
	$aoff = $boff + $blen;

	$hdr{'deep'} = 1;
	$hdr{'bufsize'} = $bufsize;
	$hdr{'hdroffset'} = $hdroffset;
	} else {
	# It is a BIOS PXE file

	return undef if ($magic != 0x2983c8ac);
	return undef if ($len < 7*4);

	$hdr{'deep'} = 0;
	}

	if ($blen == 0) {
	$bdata = '';
	} else {
	return undef unless (seek($file, $boff, SEEK_SET));
	return undef unless (read($file, $bdata, $blen) == $blen);
	$patch_start = $boff if ($boff < patch_start);
	}

	if ($alen == 0) {
	$adata = '';
	} else {
	return undef unless (seek($file, $aoff, SEEK_SET));
	return undef unless (read($file, $adata, $alen) == $alen);
	$patch_start = $aoff if ($aoff < $patch_start);
	}

	$hdr{'patch_start'} = $patch_start;

	return (\%hdr, $bdata, $adata);
	}

	sub write_optsets($$@)
	{
	my($file, $hdr, $bdata, $adata) = @_;
	my $boff = 0;
	my $aoff = 0;
	my $bufsize = 0;
	my $patch_start = $hdr->{'patch_start'};
	my $len;

	$bdata .= "\xff" unless ($bdata eq '');
	$adata .= "\xff" unless ($adata eq '');

	$len = length($bdata) + length($adata);

	if (defined($hdr->{'bufsize'})) {
	return undef unless ($len <= $hdr->{'bufsize'});
	}

	return undef unless (seek($file, $patch_start, SEEK_SET));

	if (length($bdata)) {
	$boff = $patch_start;
	return undef unless (print $file $bdata);
	$patch_start += length($bdata);
	}

	if (length($adata)) {
	$aoff = $patch_start;
	return undef unless (print $file $adata);
	$patch_start += length($adata);
	}

	if ($hdr->{'deep'}) {
	return undef unless (print $file "\0" x ($hdr->{'bufsize'} - $len));
	return undef unless (seek($file, $hdr->{'hdroffset'} + 16, SEEK_SET));
	my $hdr = pack("VV", length($bdata), length($adata));
	return undef unless (print $file $hdr);
	} else {
	my $hdr = pack("VVVV", $boff, length($bdata), $aoff, length($adata));

	return undef unless (seek($file, 8+3*4, SEEK_SET));
	return undef unless (print $file $hdr);

	truncate($file, $patch_start);
	}

	return 1;
	}

	sub delete_option($$)
	{
	my ($num, $block) = @_;
	my $o, $l, $c, $x;

	$x = 0;
	while ($x < length($block)) {
	($o, $l) = unpack("CC", substr($block, $x, 2));
	if ($o == $num) {
	# Delete this option
	substr($block, $x, $l+2) = '';
	} elsif ($o == 0) {
	# Delete a null option
	substr($block, $x, 1) = '';
	} elsif ($o == 255) {
	# End marker - truncate block
	$block = substr($block, 0, $x);
	last;
	} else {
	# Skip to the next option
	$x += $l+2;
	}
	}

	return $block;
	}

	sub add_option($$$)
	{
	my ($num, $data, $block) = @_;

	$block = delete_option($num, $block);

	if (length($data) == 0) {
	return $block;
	} elsif (length($data) > 255) {
	die "$0: option $num has too much data (max 255 bytes)\n";
	} else {
	return $block . pack("CC", $num, length($data)) . $data;
	}
	}

	sub list_options($$)
	{
	my($pfx, $data) = @_;
	my $x, $o, $l;

	while ($x < length($data)) {
	($o, $l) = unpack("CC", substr($data, $x, 2));

	if ($o == 0) {
	$x++;
	} elsif ($o == 255) {
	last;
	} else {
	my $odata = substr($data, $x+2, $l);
	last if (length($odata) != $l); # Incomplete option

	printf "%s%-20s %s\n", $pfx,
	$option_names{$o} \|\| sprintf("%d", $o),
	show_option($o, $odata);

	$x += $l+2;
	}
	}
	}

	sub usage()
	{
	my $i;

	print STDERR "Usage: $0 options pxelinux.0\n";
	print STDERR "Options:\n";
	print STDERR "--before option value -b Add an option before DHCP data\n";
	print STDERR "--after option value -a Add an option after DHCP data\n";
	print STDERR "--delete option -d Delete an option\n";
	print STDERR "--list -l List set options\n";
	print STDERR "--dry-run -n Don't modify the target file\n";
	print STDERR "--help -h Display this help text\n";
	print STDERR "\n";
	print STDERR "The following DHCP options are currently recognized:\n";
	printf STDERR "%-23s %-3s %s\n", 'Name', 'Num', 'Value Format';

	foreach $i (sort { $a <=> $b } keys(%option_names)) {
	printf STDERR "%-23s %3d %s\n",
	$option_names{$i}, $i, $option_format{$i}[0];
	}
	}

	%option_rnames = ();
	foreach $opt (keys(%option_names)) {
	$option_rnames{$option_names{$opt}} = $opt;
	}

	%before = ();
	%after = ();
	@clear = ();
	$usage = 0;
	$err = 0;
	$list = 0;
	$no_write = 0;
	undef $file;

	while (defined($opt = shift(@ARGV))) {
	if ($opt !~ /^-/) {
	if (defined($file)) {
	$err = $usage = 1;
	last;
	}
	$file = $opt;
	} elsif ($opt eq '-b' \|\| $opt eq '--before') {
	$oname = shift(@ARGV);
	$odata = shift(@ARGV);

	if (!defined($odata)) {
	$err = $usage = 1;
	last;
	}

	$onum = option_number($oname);
	if (!defined($onum)) {
	print STDERR "$0: unknown option name: $oname\n";
	$err = 1;
	next;
	}

	$odata = parse_option($onum, $odata);
	if (!defined($odata)) {
	print STDERR "$0: unable to parse data for option $oname\n";
	$err = 1;
	next;
	}

	delete $after{$onum};
	$before{$onum} = $odata;
	push(@clear, $onum);
	} elsif ($opt eq '-a' \|\| $opt eq '--after') {
	$oname = shift(@ARGV);
	$odata = shift(@ARGV);

	if (!defined($odata)) {
	$err = $usage = 1;
	last;
	}

	$onum = option_number($oname);
	if (!defined($onum)) {
	print STDERR "$0: unknown option name: $oname\n";
	$err = 1;
	next;
	}

	$odata = parse_option($onum, $odata);
	if (!defined($odata)) {
	print STDERR "$0: unable to parse data for option $oname\n";
	$err = 1;
	next;
	}

	delete $before{$onum};
	$after{$onum} = $odata;
	push(@clear, $onum);
	} elsif ($opt eq '-d' \|\| $opt eq '--delete') {
	$oname = shift(@ARGV);

	if (!defined($oname)) {
	$err = $usage = 1;
	last;
	}

	$onum = option_number($oname);
	if (!defined($onum)) {
	print STDERR "$0: unknown option name: $oname\n";
	$err = 1;
	next;
	}

	push(@clear, $onum);
	delete $before{$onum};
	delete $after{$onum};
	} elsif ($opt eq '-n' \|\| $opt eq '--no-write' \|\| $opt eq '--dry-run') {
	$no_write = 1;
	} elsif ($opt eq '-l' \|\| $opt eq '--list') {
	$list = 1;
	} elsif ($opt eq '-h' \|\| $opt eq '--help') {
	$usage = 1;
	} else {
	print STDERR "Invalid option: $opt\n";
	$err = $usage = 1;
	}
	}

	if (!defined($file) && !$usage) {
	$err = $usage = 1;
	}
	if ($usage) {
	usage();
	}
	if ($err \|\| $usage) {
	exit($err);
	}

	if (!scalar(@clear)) {
	$no_write = 1; # No modifications requested
	}

	$mode = $no_write ? '<' : '+<';

	open(FILE, $mode, $file)
	or die "$0: cannot open: $file: $!\n";
	($hdrinfo, @data) = read_optsets(\*FILE);
	if (!defined($hdrinfo)) {
	die "$0: $file: patch block not found or file corrupt\n";
	}

	foreach $o (@clear) {
	$data[0] = delete_option($o, $data[0]);
	$data[1] = delete_option($o, $data[1]);
	}
	foreach $o (keys(%before)) {
	$data[0] = add_option($o, $before{$o}, $data[0]);
	}
	foreach $o (keys(%after)) {
	$data[1] = add_option($o, $after{$o}, $data[1]);
	}

	if ($list) {
	list_options('-b ', $data[0]);
	list_options('-a ', $data[1]);
	}

	if (!$no_write) {
	if (!write_optsets(\*FILE, $hdrinfo, @data)) {
	die "$0: $file: failed to write options: $!\n";
	}
	}

	close(FILE);
	exit 0;