Coro/myhttpd/httpd.pl

use Coro;
use Coro::Semaphore;
use Coro::Event;
use Coro::Socket;

no utf8;
use bytes;

# at least on my machine, this thingy serves files
# quite a bit faster than apache, ;)
# and quite a bit slower than thttpd :(

$SIG{PIPE} = 'IGNORE';
   
sub slog {
   my $level = shift;
   my $format = shift;
   printf "---: $format\n", @_;
}

my $connections = new Coro::Semaphore $MAX_CONNECTS;

my @newcons;
my @pool;

# one "execution thread"
sub handler {
   while () {
      my $new = pop @newcons;
      if ($new) {
         eval {
            conn->new(@$new)->handle;
         };
         slog 1, "$@" if $@ && !ref $@;
         $connections->up;
      } else {
         last if @pool >= $MAX_POOL;
         push @pool, $Coro::current;
         schedule;
      }
   }
}

my $http_port = new Coro::Socket
        LocalAddr => $SERVER_HOST,
        LocalPort => $SERVER_PORT,
        ReuseAddr => 1,
        Listen => 1,
   or die "unable to start server";

push @listen_sockets, $http_port;

# the "main thread"
async {
   slog 1, "accepting connections";
   while () {
      $connections->down;
      push @newcons, [$http_port->accept];
      #slog 3, "accepted @$connections ".scalar(@pool);
      $::NOW = time;
      if (@pool) {
         (pop @pool)->ready;
      } else {
         async \&handler;
      }

   }
};

package conn;

use Socket;
use HTTP::Date;
use Convert::Scalar 'weaken';

our %conn; # $conn{ip}{fh} => connobj
our %blocked;
our %mimetype;

sub read_mimetypes {
   local *M;
   if (open M, "<mimetypes") {
      while (<M>) {
         if (/^([^#]\S+)\t+(\S+)$/) {
            $mimetype{lc $1} = $2;
         }
      }
   } else {
      $self->slog(1, "cannot open mimetypes\n");
   }
}

sub new {
   my $class = shift;
   my $peername = shift;
   my $fh = shift;
   my $self = bless { fh => $fh }, $class;
   my (undef, $iaddr) = unpack_sockaddr_in $peername
      or $self->err(500, "unable to decode peername");

   $self->{remote_addr} = inet_ntoa $iaddr;

   # enter ourselves into various lists
   weaken ($conn{$self->{remote_addr}}{$self*1} = $self);

   $self;
}

sub DESTROY {
   my $self = shift;
   delete $conn{$self->{remote_addr}}{$self*1};
   delete $uri{$self->{uri}}{$self*1};
}

sub slog {
   my $self = shift;
   main::slog($_[0], "$self->{remote_addr}> $_[1]");
}

sub response {
   my ($self, $code, $msg, $hdr, $content) = @_;
   my $res = "HTTP/1.0 $code $msg\015\012";

   $res .= "Connection: close\015\012";
   $res .= "Date: ".(time2str $::NOW)."\015\012"; # slow? nah. :(

   while (my ($h, $v) = each %$hdr) {
      $res .= "$h: $v\015\012"
   }

   $res .= "\015\012$content" if defined $content;

   print STDERR "$self->{remote_addr} \"$self->{uri}\" $code ".$hdr->{"Content-Length"}." \"$self->{h}{referer}\"\n";#d#

   print {$self->{fh}} $res;
}

sub err {
   my $self = shift;
   my ($code, $msg, $hdr, $content) = @_;

   unless (defined $content) {
      $content = "$code $msg";
      $hdr->{"Content-Type"} = "text/plain";
      $hdr->{"Content-Length"} = length $content;
   }

   $self->response($code, $msg, $hdr, $content);

   die bless {}, err::;
}

sub err_blocked {
   my $self = shift;
   my $ip = $self->{remote_addr};
   my $time = time2str $blocked{$ip} = $::NOW + $::BLOCKTIME;
   $self->err(403, "too many connections",
              {
                 "Content-Type" => "text/html",
                 "Retry-After" => $::BLOCKTIME
              },
              <<EOF);
<html><p>
You have been blocked because you opened too many connections. You
may retry at</p>

   <p><blockquote>$time.</blockquote></p>
   
<p>Until then, each new access will renew the block. You might want to have a
look at the <a href="http://www.goof.com/pcg/marc/animefaq.html">FAQ</a>.</p>
</html>
EOF
}

sub handle {
   my $self = shift;
   my $fh = $self->{fh};

   #while() {
      $self->{h} = {};

      # read request and parse first line
      $fh->timeout($::REQ_TIMEOUT);
      my $req = $fh->readline("\015\012\015\012");
      $fh->timeout($::RES_TIMEOUT);

      defined $req or
         $self->err(408, "request timeout");

      my $ip = $self->{remote_addr};

      if ($blocked{$ip}) {
         $self->err_blocked($blocked{$ip})
            if $blocked{$ip} > $::NOW;

         delete $blocked{$ip};
      }

      if (%{$conn{$ip}} > $::MAX_CONN_IP) {
         $self->slog("blocked ip $ip");
         $self->err_blocked;
      }

      $req =~ /^(?:\015\012)?
                (GET|HEAD) \040+
                ([^\040]+) \040+
                HTTP\/([0-9]+\.[0-9]+)
                \015\012/gx
         or $self->err(403, "method not allowed", { Allow => "GET,HEAD" });

      $2 ne "1.0"
         or $self->err(506, "http protocol version not supported");

      $self->{method} = $1;
      $self->{uri} = $2;

      # parse headers
      {
         my (%hdr, $h, $v);

         $hdr{lc $1} .= ",$2"
            while $req =~ /\G
                  ([^:\000-\040]+):
                  [\008\040]*
                  ((?: [^\015\012]+ | \015\012[\008\040] )*)
                  \015\012
               /gxc;

         $req =~ /\G\015\012$/
            or $self->err(400, "bad request");

         $self->{h}{$h} = substr $v, 1
            while ($h, $v) = each %hdr;
      }

      $self->{server_port} = $self->{h}{host} =~ s/:([0-9]+)$// ? $1 : 80;

      weaken ($uri{$self->{uri}}{$self*1} = $self);

      $self->map_uri;
      $self->respond;
   #}
}

# uri => path mapping
sub map_uri {
   my $self = shift;
   my $host = $self->{h}{host} || "default";
   my $uri = $self->{uri};

   # some massaging, also makes it more secure
   $uri =~ s/%([0-9a-fA-F][0-9a-fA-F])/chr hex $1/ge;
   $uri =~ s%//+%/%g;
   $uri =~ s%/\.(?=/|$)%%g;
   1 while $uri =~ s%/[^/]+/\.\.(?=/|$)%%;

   $uri =~ m%^/?\.\.(?=/|$)%
      and $self->err(400, "bad request");

   $self->{name} = $uri;

   # now do the path mapping
   $self->{path} = "$::DOCROOT/$host$uri";

   $self->access_check;
}

sub server_address {
   my $self = shift;
   my ($port, $iaddr) = unpack_sockaddr_in $self->{fh}->getsockname
      or $self->err(500, "unable to get socket name");
   ((inet_ntoa $iaddr), $port);
}

sub server_host {
   my $self = shift;
   if (exists $self->{h}{host}) {
      return $self->{h}{host};
   } else {
      return (($self->server_address)[0]);
   }
}

sub server_hostport {
   my $self = shift;
   my ($host, $port);
   if (exists $self->{h}{host}) {
      ($host, $port) = ($self->{h}{host}, $self->{server_port});
   } else {
      ($host, $port) = $self->server_address;
   }
   $port = $port == 80 ? "" : ":$port";
   $host.$port;
}

sub _cgi {
   my $self = shift;
   my $path = shift;
   my $fh;

   # no two-way xxx supported
   if (0 == fork) {
      open STDOUT, ">&".fileno($self->{fh});
      if (chdir $::DOCROOT) {
         $ENV{SERVER_SOFTWARE} = "thttpd-myhttpd"; # we are thttpd-alike
         $ENV{HTTP_HOST}       = $self->server_host;
         $ENV{HTTP_PORT}       = $self->{server_host};
         $ENV{SCRIPT_NAME}     = $self->{name};
         exec $::INDEXPROG;
      }
      Coro::State::_exit(0);
   } else {
   }
}

sub respond {
   my $self = shift;
   my $path = $self->{path};

   stat $path
      or $self->err(404, "not found");

   # idiotic netscape sends idiotic headers AGAIN
   my $ims = $self->{h}{"if-modified-since"} =~ /^([^;]+)/
             ? str2time $1 : 0;

   if (-d _ && -r _) {
      # directory
      if ($path !~ /\/$/) {
         # create a redirect to get the trailing "/"
         my $host = $self->server_hostport;
         $self->err(301, "moved permanently", { Location =>  "http://$host$self->{uri}/" });
      } else {
         $ims < (stat _)[9]
            or $self->err(304, "not modified");

         if ($self->{method} eq "GET") {
            if (-r "$path/index.html") {
               $self->{path} .= "/index.html";
               $self->handle_file;
            } else {
               $self->handle_dir;
            }
         }
      }
   } elsif (-f _ && -r _) {
      -x _ and $self->err(403, "forbidden");
      $self->handle_file;
   } else {
      $self->err(404, "not found");
   }
}

sub handle_dir {
   my $self = shift;
   $self->_cgi($::INDEXPROG);
}

sub handle_file {
   my $self = shift;
   my $length = -s _;
   my $hdr = {
      "Last-Modified"  => time2str ((stat _)[9]),
   };

   my @code = (200, "ok");
   my ($l, $h);

   if ($self->{h}{range} =~ /^bytes=(.*)$/) {
      for (split /,/, $1) {
         if (/^-(\d+)$/) {
            ($l, $h) = ($length - $1, $length - 1);
         } elsif (/^(\d+)-(\d*)$/) {
            ($l, $h) = ($1, ($2 ne "" || $2 >= $length) ? $2 : $length - 1);
         } else {
            ($l, $h) = (0, $length - 1);
            goto ignore;
         }
         goto satisfiable if $l >= 0 && $l < $length && $h >= 0 && $h > $l;
      }
      $hdr->{"Content-Range"} = "bytes */$length";
      $self->err(416, "not satisfiable", $hdr);

satisfiable:
      # check for segmented downloads
      if ($l && $NO_SEGMENTED) {
         if (%{$uri{$self->{uri}}} > 1) {
            $self->slog("segmented download refused\n");
            $self->err(400, "segmented downloads are not allowed");
         }
      }

      $hdr->{"Content-Range"} = "bytes $l-$h/$length";
      @code = (206, "partial content");
      $length = $h - $l + 1;

ignore:
   } else {
      ($l, $h) = (0, $length - 1);
   }

   $self->{path} =~ /\.([^.]+)$/;
   $hdr->{"Content-Type"} = $mimetype{lc $1} || "application/octet-stream";
   $hdr->{"Content-Length"} = $length;

   $self->response(@code, $hdr, "");

   if ($self->{method} eq "GET") {
      my ($fh, $buf);
      open $fh, "<", $self->{path}
         or die "$self->{path}: late open failure ($!)";

      if ($l) {
         sysseek $fh, $l, 0
            or die "$self->{path}: cannot seek to $l ($!)";
      }

      $h -= $l - 1;

      while ($h > 0) {
         $h -= sysread $fh, $buf, $h > $::BUFSIZE ? $::BUFSIZE : $h;
         $self->{fh}->syswrite($buf)
            or last;
      }
   }

   close $fh;
}

1;
Revision:	1.9
Committed:	Sat Aug 11 12:49:21 2001 UTC (22 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.8:	+16 -6 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	use Coro;
2			use Coro::Semaphore;
3			use Coro::Event;
4			use Coro::Socket;
5
6			no utf8;
7			use bytes;
8
9			# at least on my machine, this thingy serves files
10			# quite a bit faster than apache, ;)
11			# and quite a bit slower than thttpd :(
12
13			$SIG{PIPE} = 'IGNORE';
14
15			sub slog {
16			my $level = shift;
17			my $format = shift;
18			printf "---: $format\n", @_;
19			}
20
21			my $connections = new Coro::Semaphore $MAX_CONNECTS;
22
23	root	1.6	my @newcons;
24	root	1.1	my @pool;
25
26	root	1.2	# one "execution thread"
27	root	1.1	sub handler {
28			while () {
29	root	1.6	my $new = pop @newcons;
30			if ($new) {
31	root	1.1	eval {
32	root	1.6	conn->new(@$new)->handle;
33	root	1.1	};
34			slog 1, "$@" if $@ && !ref $@;
35			$connections->up;
36			} else {
37			last if @pool >= $MAX_POOL;
38			push @pool, $Coro::current;
39			schedule;
40			}
41			}
42			}
43
44	root	1.4	my $http_port = new Coro::Socket
45			LocalAddr => $SERVER_HOST,
46			LocalPort => $SERVER_PORT,
47			ReuseAddr => 1,
48			Listen => 1,
49			or die "unable to start server";
50
51			push @listen_sockets, $http_port;
52
53	root	1.2	# the "main thread"
54	root	1.1	async {
55			slog 1, "accepting connections";
56			while () {
57			$connections->down;
58	root	1.6	push @newcons, [$http_port->accept];
59	root	1.1	#slog 3, "accepted @$connections ".scalar(@pool);
60	root	1.3	$::NOW = time;
61	root	1.1	if (@pool) {
62			(pop @pool)->ready;
63			} else {
64			async \&handler;
65			}
66
67			}
68			};
69
70			package conn;
71
72			use Socket;
73			use HTTP::Date;
74	root	1.2	use Convert::Scalar 'weaken';
75
76	root	1.3	our %conn; # $conn{ip}{fh} => connobj
77			our %blocked;
78	root	1.9	our %mimetype;
79
80			sub read_mimetypes {
81			local *M;
82			if (open M, "<mimetypes") {
83			while (<M>) {
84			if (/^([^#]\S+)\t+(\S+)$/) {
85			$mimetype{lc $1} = $2;
86			}
87			}
88			} else {
89			$self->slog(1, "cannot open mimetypes\n");
90			}
91			}
92	root	1.1
93			sub new {
94			my $class = shift;
95	root	1.6	my $peername = shift;
96	root	1.1	my $fh = shift;
97	root	1.2	my $self = bless { fh => $fh }, $class;
98	root	1.6	my (undef, $iaddr) = unpack_sockaddr_in $peername
99			or $self->err(500, "unable to decode peername");
100	root	1.7
101	root	1.3	$self->{remote_addr} = inet_ntoa $iaddr;
102	root	1.2
103			# enter ourselves into various lists
104	root	1.3	weaken ($conn{$self->{remote_addr}}{$self*1} = $self);
105
106	root	1.2	$self;
107			}
108
109			sub DESTROY {
110			my $self = shift;
111	root	1.3	delete $conn{$self->{remote_addr}}{$self*1};
112			delete $uri{$self->{uri}}{$self*1};
113	root	1.1	}
114
115			sub slog {
116	root	1.4	my $self = shift;
117			main::slog($_[0], "$self->{remote_addr}> $_[1]");
118	root	1.1	}
119
120	root	1.4	sub response {
121	root	1.1	my ($self, $code, $msg, $hdr, $content) = @_;
122			my $res = "HTTP/1.0 $code $msg\015\012";
123
124	root	1.4	$res .= "Connection: close\015\012";
125			$res .= "Date: ".(time2str $::NOW)."\015\012"; # slow? nah. :(
126	root	1.1
127			while (my ($h, $v) = each %$hdr) {
128			$res .= "$h: $v\015\012"
129			}
130	root	1.4
131	root	1.1	$res .= "\015\012$content" if defined $content;
132
133	root	1.3	print STDERR "$self->{remote_addr} \"$self->{uri}\" $code ".$hdr->{"Content-Length"}." \"$self->{h}{referer}\"\n";#d#
134	root	1.2
135	root	1.1	print {$self->{fh}} $res;
136			}
137
138			sub err {
139			my $self = shift;
140			my ($code, $msg, $hdr, $content) = @_;
141
142			unless (defined $content) {
143			$content = "$code $msg";
144			$hdr->{"Content-Type"} = "text/plain";
145			$hdr->{"Content-Length"} = length $content;
146			}
147
148	root	1.4	$self->response($code, $msg, $hdr, $content);
149	root	1.1
150			die bless {}, err::;
151			}
152
153	root	1.3	sub err_blocked {
154			my $self = shift;
155			my $ip = $self->{remote_addr};
156			my $time = time2str $blocked{$ip} = $::NOW + $::BLOCKTIME;
157			$self->err(403, "too many connections",
158	root	1.4	{
159			"Content-Type" => "text/html",
160			"Retry-After" => $::BLOCKTIME
161			},
162	root	1.3	<<EOF);
163	root	1.4	<html><p>
164	root	1.3	You have been blocked because you opened too many connections. You
165	root	1.4	may retry at</p>
166
167			<p><blockquote>$time.</blockquote></p>
168
169			<p>Until then, each new access will renew the block. You might want to have a
170			look at the <a href="http://www.goof.com/pcg/marc/animefaq.html">FAQ</a>.</p>
171			</html>
172	root	1.3	EOF
173			}
174
175	root	1.1	sub handle {
176			my $self = shift;
177			my $fh = $self->{fh};
178
179			#while() {
180			$self->{h} = {};
181
182			# read request and parse first line
183			$fh->timeout($::REQ_TIMEOUT);
184			my $req = $fh->readline("\015\012\015\012");
185			$fh->timeout($::RES_TIMEOUT);
186
187			defined $req or
188			$self->err(408, "request timeout");
189
190	root	1.3	my $ip = $self->{remote_addr};
191
192			if ($blocked{$ip}) {
193			$self->err_blocked($blocked{$ip})
194			if $blocked{$ip} > $::NOW;
195
196			delete $blocked{$ip};
197			}
198
199			if (%{$conn{$ip}} > $::MAX_CONN_IP) {
200			$self->slog("blocked ip $ip");
201			$self->err_blocked;
202			}
203
204	root	1.1	$req =~ /^(?:\015\012)?
205			(GET\|HEAD) \040+
206			([^\040]+) \040+
207			HTTP\/([0-9]+\.[0-9]+)
208			\015\012/gx
209			or $self->err(403, "method not allowed", { Allow => "GET,HEAD" });
210
211			$2 ne "1.0"
212			or $self->err(506, "http protocol version not supported");
213
214			$self->{method} = $1;
215			$self->{uri} = $2;
216
217			# parse headers
218			{
219			my (%hdr, $h, $v);
220
221			$hdr{lc $1} .= ",$2"
222			while $req =~ /\G
223			([^:\000-\040]+):
224			[\008\040]*
225			((?: [^\015\012]+ \| \015\012[\008\040] )*)
226			\015\012
227			/gxc;
228
229			$req =~ /\G\015\012$/
230			or $self->err(400, "bad request");
231
232			$self->{h}{$h} = substr $v, 1
233			while ($h, $v) = each %hdr;
234			}
235
236			$self->{server_port} = $self->{h}{host} =~ s/:([0-9]+)$// ? $1 : 80;
237	root	1.3
238			weaken ($uri{$self->{uri}}{$self*1} = $self);
239	root	1.1
240			$self->map_uri;
241			$self->respond;
242			#}
243			}
244
245			# uri => path mapping
246			sub map_uri {
247			my $self = shift;
248			my $host = $self->{h}{host} \|\| "default";
249			my $uri = $self->{uri};
250
251			# some massaging, also makes it more secure
252			$uri =~ s/%([0-9a-fA-F][0-9a-fA-F])/chr hex $1/ge;
253			$uri =~ s%//+%/%g;
254			$uri =~ s%/\.(?=/\|$)%%g;
255			1 while $uri =~ s%/[^/]+/\.\.(?=/\|$)%%;
256
257			$uri =~ m%^/?\.\.(?=/\|$)%
258			and $self->err(400, "bad request");
259
260			$self->{name} = $uri;
261
262			# now do the path mapping
263			$self->{path} = "$::DOCROOT/$host$uri";
264	root	1.7
265			$self->access_check;
266	root	1.1	}
267
268			sub server_address {
269			my $self = shift;
270			my ($port, $iaddr) = unpack_sockaddr_in $self->{fh}->getsockname
271			or $self->err(500, "unable to get socket name");
272			((inet_ntoa $iaddr), $port);
273			}
274
275			sub server_host {
276			my $self = shift;
277			if (exists $self->{h}{host}) {
278			return $self->{h}{host};
279			} else {
280			return (($self->server_address)[0]);
281			}
282			}
283
284			sub server_hostport {
285			my $self = shift;
286			my ($host, $port);
287			if (exists $self->{h}{host}) {
288			($host, $port) = ($self->{h}{host}, $self->{server_port});
289			} else {
290			($host, $port) = $self->server_address;
291			}
292			$port = $port == 80 ? "" : ":$port";
293			$host.$port;
294			}
295
296			sub _cgi {
297			my $self = shift;
298			my $path = shift;
299			my $fh;
300
301			# no two-way xxx supported
302			if (0 == fork) {
303			open STDOUT, ">&".fileno($self->{fh});
304			if (chdir $::DOCROOT) {
305			$ENV{SERVER_SOFTWARE} = "thttpd-myhttpd"; # we are thttpd-alike
306			$ENV{HTTP_HOST} = $self->server_host;
307			$ENV{HTTP_PORT} = $self->{server_host};
308			$ENV{SCRIPT_NAME} = $self->{name};
309			exec $::INDEXPROG;
310			}
311			Coro::State::_exit(0);
312			} else {
313			}
314			}
315
316			sub respond {
317			my $self = shift;
318			my $path = $self->{path};
319
320			stat $path
321			or $self->err(404, "not found");
322
323			# idiotic netscape sends idiotic headers AGAIN
324			my $ims = $self->{h}{"if-modified-since"} =~ /^([^;]+)/
325			? str2time $1 : 0;
326
327			if (-d _ && -r _) {
328			# directory
329			if ($path !~ /\/$/) {
330			# create a redirect to get the trailing "/"
331			my $host = $self->server_hostport;
332			$self->err(301, "moved permanently", { Location => "http://$host$self->{uri}/" });
333			} else {
334			$ims < (stat _)[9]
335			or $self->err(304, "not modified");
336
337			if ($self->{method} eq "GET") {
338			if (-r "$path/index.html") {
339			$self->{path} .= "/index.html";
340			$self->handle_file;
341			} else {
342			$self->handle_dir;
343			}
344			}
345			}
346			} elsif (-f _ && -r _) {
347			-x _ and $self->err(403, "forbidden");
348			$self->handle_file;
349			} else {
350			$self->err(404, "not found");
351			}
352			}
353
354			sub handle_dir {
355			my $self = shift;
356			$self->_cgi($::INDEXPROG);
357			}
358
359			sub handle_file {
360			my $self = shift;
361			my $length = -s _;
362			my $hdr = {
363			"Last-Modified" => time2str ((stat _)[9]),
364			};
365
366			my @code = (200, "ok");
367			my ($l, $h);
368
369			if ($self->{h}{range} =~ /^bytes=(.*)$/) {
370			for (split /,/, $1) {
371			if (/^-(\d+)$/) {
372			($l, $h) = ($length - $1, $length - 1);
373			} elsif (/^(\d+)-(\d*)$/) {
374			($l, $h) = ($1, ($2 ne "" \|\| $2 >= $length) ? $2 : $length - 1);
375			} else {
376			($l, $h) = (0, $length - 1);
377			goto ignore;
378			}
379			goto satisfiable if $l >= 0 && $l < $length && $h >= 0 && $h > $l;
380			}
381			$hdr->{"Content-Range"} = "bytes */$length";
382			$self->err(416, "not satisfiable", $hdr);
383
384			satisfiable:
385	root	1.4	# check for segmented downloads
386			if ($l && $NO_SEGMENTED) {
387			if (%{$uri{$self->{uri}}} > 1) {
388			$self->slog("segmented download refused\n");
389			$self->err(400, "segmented downloads are not allowed");
390			}
391			}
392
393	root	1.1	$hdr->{"Content-Range"} = "bytes $l-$h/$length";
394			@code = (206, "partial content");
395			$length = $h - $l + 1;
396
397			ignore:
398			} else {
399			($l, $h) = (0, $length - 1);
400			}
401
402	root	1.9	$self->{path} =~ /\.([^.]+)$/;
403			$hdr->{"Content-Type"} = $mimetype{lc $1} \|\| "application/octet-stream";
404	root	1.1	$hdr->{"Content-Length"} = $length;
405
406	root	1.4	$self->response(@code, $hdr, "");
407	root	1.1
408			if ($self->{method} eq "GET") {
409			my ($fh, $buf);
410			open $fh, "<", $self->{path}
411			or die "$self->{path}: late open failure ($!)";
412
413			if ($l) {
414			sysseek $fh, $l, 0
415			or die "$self->{path}: cannot seek to $l ($!)";
416			}
417
418			$h -= $l - 1;
419
420			while ($h > 0) {
421	root	1.5	$h -= sysread $fh, $buf, $h > $::BUFSIZE ? $::BUFSIZE : $h;
422			$self->{fh}->syswrite($buf)
423	root	1.1	or last;
424			}
425			}
426
427			close $fh;
428	root	1.7	}
429
430	root	1.2	1;