晋太元中,武陵人捕鱼为业。缘溪行,忘路之远近。忽逢桃花林,夹岸数百步,中无杂树,芳草鲜美,落英缤纷。渔人甚异之,复前行,欲穷其林。 林尽水源,便得一山,山有小口,仿佛若有光。便舍船,从口入。初极狭,才通人。复行数十步,豁然开朗。土地平旷,屋舍俨然,有良田、美池、桑竹之属。阡陌交通,鸡犬相闻。其中往来种作,男女衣着,悉如外人。黄发垂髫,并怡然自乐。 见渔人,乃大惊,问所从来。具答之。便要还家,设酒杀鸡作食。村中闻有此人,咸来问讯。自云先世避秦时乱,率妻子邑人来此绝境,不复出焉,遂与外人间隔。问今是何世,乃不知有汉,无论魏晋。此人一一为具言所闻,皆叹惋。余人各复延至其家,皆出酒食。停数日,辞去。此中人语云:“不足为外人道也。”(间隔 一作:隔绝) 既出,得其船,便扶向路,处处志之。及郡下,诣太守,说如此。太守即遣人随其往,寻向所志,遂迷,不复得路。 南阳刘子骥,高尚士也,闻之,欣然规往。未果,寻病终。后遂无问津者。
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# IO::Socket.pm
#
# Copyright (c) 1997-8 Graham Barr <gbarr@pobox.com>. All rights reserved.
# This program is free software; you can redistribute it and/or
# modify it under the same terms as Perl itself.
package IO::Socket;
require 5.006;
use IO::Handle;
use Socket 1.3;
use Carp;
use strict;
our(@ISA, $VERSION, @EXPORT_OK);
use Exporter;
use Errno;
# legacy
require IO::Socket::INET;
require IO::Socket::UNIX if ($^O ne 'epoc' && $^O ne 'symbian');
@ISA = qw(IO::Handle);
$VERSION = "1.38";
@EXPORT_OK = qw(sockatmark);
sub import {
my $pkg = shift;
if (@_ && $_[0] eq 'sockatmark') { # not very extensible but for now, fast
Exporter::export_to_level('IO::Socket', 1, $pkg, 'sockatmark');
} else {
my $callpkg = caller;
Exporter::export 'Socket', $callpkg, @_;
}
}
sub new {
my($class,%arg) = @_;
my $sock = $class->SUPER::new();
$sock->autoflush(1);
${*$sock}{'io_socket_timeout'} = delete $arg{Timeout};
return scalar(%arg) ? $sock->configure(\%arg)
: $sock;
}
my @domain2pkg;
sub register_domain {
my($p,$d) = @_;
$domain2pkg[$d] = $p;
}
sub configure {
my($sock,$arg) = @_;
my $domain = delete $arg->{Domain};
croak 'IO::Socket: Cannot configure a generic socket'
unless defined $domain;
croak "IO::Socket: Unsupported socket domain"
unless defined $domain2pkg[$domain];
croak "IO::Socket: Cannot configure socket in domain '$domain'"
unless ref($sock) eq "IO::Socket";
bless($sock, $domain2pkg[$domain]);
$sock->configure($arg);
}
sub socket {
@_ == 4 or croak 'usage: $sock->socket(DOMAIN, TYPE, PROTOCOL)';
my($sock,$domain,$type,$protocol) = @_;
socket($sock,$domain,$type,$protocol) or
return undef;
${*$sock}{'io_socket_domain'} = $domain;
${*$sock}{'io_socket_type'} = $type;
${*$sock}{'io_socket_proto'} = $protocol;
$sock;
}
sub socketpair {
@_ == 4 || croak 'usage: IO::Socket->socketpair(DOMAIN, TYPE, PROTOCOL)';
my($class,$domain,$type,$protocol) = @_;
my $sock1 = $class->new();
my $sock2 = $class->new();
socketpair($sock1,$sock2,$domain,$type,$protocol) or
return ();
${*$sock1}{'io_socket_type'} = ${*$sock2}{'io_socket_type'} = $type;
${*$sock1}{'io_socket_proto'} = ${*$sock2}{'io_socket_proto'} = $protocol;
($sock1,$sock2);
}
sub connect {
@_ == 2 or croak 'usage: $sock->connect(NAME)';
my $sock = shift;
my $addr = shift;
my $timeout = ${*$sock}{'io_socket_timeout'};
my $err;
my $blocking;
$blocking = $sock->blocking(0) if $timeout;
if (!connect($sock, $addr)) {
if (defined $timeout && ($!{EINPROGRESS} || $!{EWOULDBLOCK})) {
require IO::Select;
my $sel = new IO::Select $sock;
undef $!;
my($r,$w,$e) = IO::Select::select(undef,$sel,$sel,$timeout);
if(@$e[0]) {
# Windows return from select after the timeout in case of
# WSAECONNREFUSED(10061) if exception set is not used.
# This behavior is different from Linux.
# Using the exception
# set we now emulate the behavior in Linux
# - Karthik Rajagopalan
$err = $sock->getsockopt(SOL_SOCKET,SO_ERROR);
$@ = "connect: $err";
}
elsif(!@$w[0]) {
$err = $! || (exists &Errno::ETIMEDOUT ? &Errno::ETIMEDOUT : 1);
$@ = "connect: timeout";
}
elsif (!connect($sock,$addr) &&
not ($!{EISCONN} || ($^O eq 'MSWin32' &&
($! == (($] < 5.019004) ? 10022 : Errno::EINVAL))))
) {
# Some systems refuse to re-connect() to
# an already open socket and set errno to EISCONN.
# Windows sets errno to WSAEINVAL (10022) (pre-5.19.4) or
# EINVAL (22) (5.19.4 onwards).
$err = $!;
$@ = "connect: $!";
}
}
elsif ($blocking || !($!{EINPROGRESS} || $!{EWOULDBLOCK})) {
$err = $!;
$@ = "connect: $!";
}
}
$sock->blocking(1) if $blocking;
$! = $err if $err;
$err ? undef : $sock;
}
# Enable/disable blocking IO on sockets.
# Without args return the current status of blocking,
# with args change the mode as appropriate, returning the
# old setting, or in case of error during the mode change
# undef.
sub blocking {
my $sock = shift;
return $sock->SUPER::blocking(@_)
if $^O ne 'MSWin32' && $^O ne 'VMS';
# Windows handles blocking differently
#
# http://groups.google.co.uk/group/perl.perl5.porters/browse_thread/thread/b4e2b1d88280ddff/630b667a66e3509f?#630b667a66e3509f
# http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winsock/winsock/ioctlsocket_2.asp
#
# 0x8004667e is FIONBIO
#
# which is used to set blocking behaviour.
# NOTE:
# This is a little confusing, the perl keyword for this is
# 'blocking' but the OS level behaviour is 'non-blocking', probably
# because sockets are blocking by default.
# Therefore internally we have to reverse the semantics.
my $orig= !${*$sock}{io_sock_nonblocking};
return $orig unless @_;
my $block = shift;
if ( !$block != !$orig ) {
${*$sock}{io_sock_nonblocking} = $block ? 0 : 1;
ioctl($sock, 0x8004667e, pack("L!",${*$sock}{io_sock_nonblocking}))
or return undef;
}
return $orig;
}
sub close {
@_ == 1 or croak 'usage: $sock->close()';
my $sock = shift;
${*$sock}{'io_socket_peername'} = undef;
$sock->SUPER::close();
}
sub bind {
@_ == 2 or croak 'usage: $sock->bind(NAME)';
my $sock = shift;
my $addr = shift;
return bind($sock, $addr) ? $sock
: undef;
}
sub listen {
@_ >= 1 && @_ <= 2 or croak 'usage: $sock->listen([QUEUE])';
my($sock,$queue) = @_;
$queue = 5
unless $queue && $queue > 0;
return listen($sock, $queue) ? $sock
: undef;
}
sub accept {
@_ == 1 || @_ == 2 or croak 'usage $sock->accept([PKG])';
my $sock = shift;
my $pkg = shift || $sock;
my $timeout = ${*$sock}{'io_socket_timeout'};
my $new = $pkg->new(Timeout => $timeout);
my $peer = undef;
if(defined $timeout) {
require IO::Select;
my $sel = new IO::Select $sock;
unless ($sel->can_read($timeout)) {
$@ = 'accept: timeout';
$! = (exists &Errno::ETIMEDOUT ? &Errno::ETIMEDOUT : 1);
return;
}
}
$peer = accept($new,$sock)
or return;
${*$new}{$_} = ${*$sock}{$_} for qw( io_socket_domain io_socket_type io_socket_proto );
return wantarray ? ($new, $peer)
: $new;
}
sub sockname {
@_ == 1 or croak 'usage: $sock->sockname()';
getsockname($_[0]);
}
sub peername {
@_ == 1 or croak 'usage: $sock->peername()';
my($sock) = @_;
${*$sock}{'io_socket_peername'} ||= getpeername($sock);
}
sub connected {
@_ == 1 or croak 'usage: $sock->connected()';
my($sock) = @_;
getpeername($sock);
}
sub send {
@_ >= 2 && @_ <= 4 or croak 'usage: $sock->send(BUF, [FLAGS, [TO]])';
my $sock = $_[0];
my $flags = $_[2] || 0;
my $peer = $_[3] || $sock->peername;
croak 'send: Cannot determine peer address'
unless(defined $peer);
my $r = defined(getpeername($sock))
? send($sock, $_[1], $flags)
: send($sock, $_[1], $flags, $peer);
# remember who we send to, if it was successful
${*$sock}{'io_socket_peername'} = $peer
if(@_ == 4 && defined $r);
$r;
}
sub recv {
@_ == 3 || @_ == 4 or croak 'usage: $sock->recv(BUF, LEN [, FLAGS])';
my $sock = $_[0];
my $len = $_[2];
my $flags = $_[3] || 0;
# remember who we recv'd from
${*$sock}{'io_socket_peername'} = recv($sock, $_[1]='', $len, $flags);
}
sub shutdown {
@_ == 2 or croak 'usage: $sock->shutdown(HOW)';
my($sock, $how) = @_;
${*$sock}{'io_socket_peername'} = undef;
shutdown($sock, $how);
}
sub setsockopt {
@_ == 4 or croak '$sock->setsockopt(LEVEL, OPTNAME, OPTVAL)';
setsockopt($_[0],$_[1],$_[2],$_[3]);
}
my $intsize = length(pack("i",0));
sub getsockopt {
@_ == 3 or croak '$sock->getsockopt(LEVEL, OPTNAME)';
my $r = getsockopt($_[0],$_[1],$_[2]);
# Just a guess
$r = unpack("i", $r)
if(defined $r && length($r) == $intsize);
$r;
}
sub sockopt {
my $sock = shift;
@_ == 1 ? $sock->getsockopt(SOL_SOCKET,@_)
: $sock->setsockopt(SOL_SOCKET,@_);
}
sub atmark {
@_ == 1 or croak 'usage: $sock->atmark()';
my($sock) = @_;
sockatmark($sock);
}
sub timeout {
@_ == 1 || @_ == 2 or croak 'usage: $sock->timeout([VALUE])';
my($sock,$val) = @_;
my $r = ${*$sock}{'io_socket_timeout'};
${*$sock}{'io_socket_timeout'} = defined $val ? 0 + $val : $val
if(@_ == 2);
$r;
}
sub sockdomain {
@_ == 1 or croak 'usage: $sock->sockdomain()';
my $sock = shift;
if (!defined(${*$sock}{'io_socket_domain'})) {
my $addr = $sock->sockname();
${*$sock}{'io_socket_domain'} = sockaddr_family($addr)
if (defined($addr));
}
${*$sock}{'io_socket_domain'};
}
sub socktype {
@_ == 1 or croak 'usage: $sock->socktype()';
my $sock = shift;
${*$sock}{'io_socket_type'} = $sock->sockopt(Socket::SO_TYPE)
if (!defined(${*$sock}{'io_socket_type'}) && defined(eval{Socket::SO_TYPE}));
${*$sock}{'io_socket_type'}
}
sub protocol {
@_ == 1 or croak 'usage: $sock->protocol()';
my($sock) = @_;
${*$sock}{'io_socket_proto'} = $sock->sockopt(Socket::SO_PROTOCOL)
if (!defined(${*$sock}{'io_socket_proto'}) && defined(eval{Socket::SO_PROTOCOL}));
${*$sock}{'io_socket_proto'};
}
1;
__END__
=head1 NAME
IO::Socket - Object interface to socket communications
=head1 SYNOPSIS
use IO::Socket;
=head1 DESCRIPTION
C<IO::Socket> provides an object interface to creating and using sockets. It
is built upon the L<IO::Handle> interface and inherits all the methods defined
by L<IO::Handle>.
C<IO::Socket> only defines methods for those operations which are common to all
types of socket. Operations which are specified to a socket in a particular
domain have methods defined in sub classes of C<IO::Socket>
C<IO::Socket> will export all functions (and constants) defined by L<Socket>.
=head1 CONSTRUCTOR
=over 4
=item new ( [ARGS] )
Creates an C<IO::Socket>, which is a reference to a
newly created symbol (see the C<Symbol> package). C<new>
optionally takes arguments, these arguments are in key-value pairs.
C<new> only looks for one key C<Domain> which tells new which domain
the socket will be in. All other arguments will be passed to the
configuration method of the package for that domain, See below.
NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE
As of VERSION 1.18 all IO::Socket objects have autoflush turned on
by default. This was not the case with earlier releases.
NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE NOTE
=back
=head1 METHODS
See L<perlfunc> for complete descriptions of each of the following
supported C<IO::Socket> methods, which are just front ends for the
corresponding built-in functions:
socket
socketpair
bind
listen
accept
send
recv
peername (getpeername)
sockname (getsockname)
shutdown
Some methods take slightly different arguments to those defined in L<perlfunc>
in attempt to make the interface more flexible. These are
=over 4
=item accept([PKG])
perform the system call C<accept> on the socket and return a new
object. The new object will be created in the same class as the listen
socket, unless C<PKG> is specified. This object can be used to
communicate with the client that was trying to connect.
In a scalar context the new socket is returned, or undef upon
failure. In a list context a two-element array is returned containing
the new socket and the peer address; the list will be empty upon
failure.
The timeout in the [PKG] can be specified as zero to effect a "poll",
but you shouldn't do that because a new IO::Select object will be
created behind the scenes just to do the single poll. This is
horrendously inefficient. Use rather true select() with a zero
timeout on the handle, or non-blocking IO.
=item socketpair(DOMAIN, TYPE, PROTOCOL)
Call C<socketpair> and return a list of two sockets created, or an
empty list on failure.
=back
Additional methods that are provided are:
=over 4
=item atmark
True if the socket is currently positioned at the urgent data mark,
false otherwise.
use IO::Socket;
my $sock = IO::Socket::INET->new('some_server');
$sock->read($data, 1024) until $sock->atmark;
Note: this is a reasonably new addition to the family of socket
functions, so all systems may not support this yet. If it is
unsupported by the system, an attempt to use this method will
abort the program.
The atmark() functionality is also exportable as sockatmark() function:
use IO::Socket 'sockatmark';
This allows for a more traditional use of sockatmark() as a procedural
socket function. If your system does not support sockatmark(), the
C<use> declaration will fail at compile time.
=item connected
If the socket is in a connected state, the peer address is returned. If the
socket is not in a connected state, undef is returned.
Note that connected() considers a half-open TCP socket to be "in a connected
state". Specifically, connected() does not distinguish between the
B<ESTABLISHED> and B<CLOSE-WAIT> TCP states; it returns the peer address,
rather than undef, in either case. Thus, in general, connected() cannot
be used to reliably learn whether the peer has initiated a graceful shutdown
because in most cases (see below) the local TCP state machine remains in
B<CLOSE-WAIT> until the local application calls shutdown() or close();
only at that point does connected() return undef.
The "in most cases" hedge is because local TCP state machine behavior may
depend on the peer's socket options. In particular, if the peer socket has
SO_LINGER enabled with a zero timeout, then the peer's close() will generate
a RST segment, upon receipt of which the local TCP transitions immediately to
B<CLOSED>, and in that state, connected() I<will> return undef.
=item protocol
Returns the numerical number for the protocol being used on the socket, if
known. If the protocol is unknown, as with an AF_UNIX socket, zero
is returned.
=item sockdomain
Returns the numerical number for the socket domain type. For example, for
an AF_INET socket the value of &AF_INET will be returned.
=item sockopt(OPT [, VAL])
Unified method to both set and get options in the SOL_SOCKET level. If called
with one argument then getsockopt is called, otherwise setsockopt is called.
=item getsockopt(LEVEL, OPT)
Get option associated with the socket. Other levels than SOL_SOCKET
may be specified here.
=item setsockopt(LEVEL, OPT, VAL)
Set option associated with the socket. Other levels than SOL_SOCKET
may be specified here.
=item socktype
Returns the numerical number for the socket type. For example, for
a SOCK_STREAM socket the value of &SOCK_STREAM will be returned.
=item timeout([VAL])
Set or get the timeout value (in seconds) associated with this socket.
If called without any arguments then the current setting is returned. If
called with an argument the current setting is changed and the previous
value returned.
=back
=head1 LIMITATIONS
On some systems, for an IO::Socket object created with new_from_fd(),
or created with accept() from such an object, the protocol(),
sockdomain() and socktype() methods may return undef.
=head1 SEE ALSO
L<Socket>, L<IO::Handle>, L<IO::Socket::INET>, L<IO::Socket::UNIX>
=head1 AUTHOR
Graham Barr. atmark() by Lincoln Stein. Currently maintained by the
Perl Porters. Please report all bugs to <perlbug@perl.org>.
=head1 COPYRIGHT
Copyright (c) 1997-8 Graham Barr <gbarr@pobox.com>. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
The atmark() implementation: Copyright 2001, Lincoln Stein <lstein@cshl.org>.
This module is distributed under the same terms as Perl itself.
Feel free to use, modify and redistribute it as long as you retain
the correct attribution.
=cut