[perl5.git] / lib / chat2.pl

# chat.pl: chat with a server
#
# This library is no longer being maintained, and is included for backward
# compatibility with Perl 4 programs which may require it.
#
# In particular, this should not be used as an example of modern Perl
# programming techniques.
#
# Suggested alternative: Socket
#
# Based on: V2.01.alpha.7 91/06/16
# Randal L. Schwartz (was <merlyn@stonehenge.com>)
# multihome additions by A.Macpherson@bnr.co.uk
# allow for /dev/pts based systems by Joe Doupnik <JRD@CC.USU.EDU>

package chat;

require 'sys/socket.ph';

if( defined( &main'PF_INET ) ){
	$pf_inet = &main'PF_INET;
	$sock_stream = &main'SOCK_STREAM;
	local($name, $aliases, $proto) = getprotobyname( 'tcp' );
	$tcp_proto = $proto;
}
else {
	# XXX hardwired $PF_INET, $SOCK_STREAM, 'tcp'
	# but who the heck would change these anyway? (:-)
	$pf_inet = 2;
	$sock_stream = 1;
	$tcp_proto = 6;
}


$sockaddr = 'S n a4 x8';
chop($thishost = `hostname`);

# *S = symbol for current I/O, gets assigned *chatsymbol....
$next = "chatsymbol000000"; # next one
$nextpat = "^chatsymbol"; # patterns that match next++, ++, ++, ++


## $handle = &chat'open_port("server.address",$port_number);
## opens a named or numbered TCP server

sub open_port { ## public
	local($server, $port) = @_;

	local($serveraddr,$serverproc);

	# We may be multi-homed, start with 0, fixup once connexion is made
	$thisaddr = "\0\0\0\0" ;
	$thisproc = pack($sockaddr, 2, 0, $thisaddr);

	*S = ++$next;
	if ($server =~ /^(\d+)+\.(\d+)\.(\d+)\.(\d+)$/) {
		$serveraddr = pack('C4', $1, $2, $3, $4);
	} else {
		local(@x) = gethostbyname($server);
		return undef unless @x;
		$serveraddr = $x[4];
	}
	$serverproc = pack($sockaddr, 2, $port, $serveraddr);
	unless (socket(S, $pf_inet, $sock_stream, $tcp_proto)) {
		($!) = ($!, close(S)); # close S while saving $!
		return undef;
	}
	unless (bind(S, $thisproc)) {
		($!) = ($!, close(S)); # close S while saving $!
		return undef;
	}
	unless (connect(S, $serverproc)) {
		($!) = ($!, close(S)); # close S while saving $!
		return undef;
	}
# We opened with the local address set to ANY, at this stage we know
# which interface we are using.  This is critical if our machine is
# multi-homed, with IP forwarding off, so fix-up.
	local($fam,$lport);
	($fam,$lport,$thisaddr) = unpack($sockaddr, getsockname(S));
	$thisproc = pack($sockaddr, 2, 0, $thisaddr);
# end of post-connect fixup
	select((select(S), $| = 1)[0]);
	$next; # return symbol for switcharound
}

## ($host, $port, $handle) = &chat'open_listen([$port_number]);
## opens a TCP port on the current machine, ready to be listened to
## if $port_number is absent or zero, pick a default port number
## process must be uid 0 to listen to a low port number

sub open_listen { ## public

	*S = ++$next;
	local($thisport) = shift || 0;
	local($thisproc_local) = pack($sockaddr, 2, $thisport, $thisaddr);
	local(*NS) = "__" . time;
	unless (socket(NS, $pf_inet, $sock_stream, $tcp_proto)) {
		($!) = ($!, close(NS));
		return undef;
	}
	unless (bind(NS, $thisproc_local)) {
		($!) = ($!, close(NS));
		return undef;
	}
	unless (listen(NS, 1)) {
		($!) = ($!, close(NS));
		return undef;
	}
	select((select(NS), $| = 1)[0]);
	local($family, $port, @myaddr) =
		unpack("S n C C C C x8", getsockname(NS));
	$S{"needs_accept"} = *NS; # so expect will open it
	(@myaddr, $port, $next); # returning this
}

## $handle = &chat'open_proc("command","arg1","arg2",...);
## opens a /bin/sh on a pseudo-tty

sub open_proc { ## public
	local(@cmd) = @_;

	*S = ++$next;
	local(*TTY) = "__TTY" . time;
	local($pty,$tty) = &_getpty(S,TTY);
	die "Cannot find a new pty" unless defined $pty;
	$pid = fork;
	die "Cannot fork: $!" unless defined $pid;
	unless ($pid) {
		close STDIN; close STDOUT; close STDERR;
		setpgrp(0,$$);
		if (open(DEVTTY, "/dev/tty")) {
		    ioctl(DEVTTY,0x20007471,0);		# XXX s/b &TIOCNOTTY
		    close DEVTTY;
		}
		open(STDIN,"<&TTY");
		open(STDOUT,">&TTY");
		open(STDERR,">&STDOUT");
		die "Oops" unless fileno(STDERR) == 2;	# sanity
		close(S);
		exec @cmd;
		die "Cannot exec @cmd: $!";
	}
	close(TTY);
	$next; # return symbol for switcharound
}

# $S is the read-ahead buffer

## $return = &chat'expect([$handle,] $timeout_time,
## 	$pat1, $body1, $pat2, $body2, ... )
## $handle is from previous &chat'open_*().
## $timeout_time is the time (either relative to the current time, or
## absolute, ala time(2)) at which a timeout event occurs.
## $pat1, $pat2, and so on are regexs which are matched against the input
## stream.  If a match is found, the entire matched string is consumed,
## and the corresponding body eval string is evaled.
##
## Each pat is a regular-expression (probably enclosed in single-quotes
## in the invocation).  ^ and $ will work, respecting the current value of $*.
## If pat is 'TIMEOUT', the body is executed if the timeout is exceeded.
## If pat is 'EOF', the body is executed if the process exits before
## the other patterns are seen.
##
## Pats are scanned in the order given, so later pats can contain
## general defaults that won't be examined unless the earlier pats
## have failed.
##
## The result of eval'ing body is returned as the result of
## the invocation.  Recursive invocations are not thought
## through, and may work only accidentally. :-)
##
## undef is returned if either a timeout or an eof occurs and no
## corresponding body has been defined.
## I/O errors of any sort are treated as eof.

$nextsubname = "expectloop000000"; # used for subroutines

sub expect { ## public
	if ($_[0] =~ /$nextpat/) {
		*S = shift;
	}
	local($endtime) = shift;

	local($timeout,$eof) = (1,1);
	local($caller) = caller;
	local($rmask, $nfound, $timeleft, $thisbuf);
	local($cases, $pattern, $action, $subname);
	$endtime += time if $endtime < 600_000_000;

	if (defined $S{"needs_accept"}) { # is it a listen socket?
		local(*NS) = $S{"needs_accept"};
		delete $S{"needs_accept"};
		$S{"needs_close"} = *NS;
		unless(accept(S,NS)) {
			($!) = ($!, close(S), close(NS));
			return undef;
		}
		select((select(S), $| = 1)[0]);
	}

	# now see whether we need to create a new sub:

	unless ($subname = $expect_subname{$caller,@_}) {
		# nope.  make a new one:
		$expect_subname{$caller,@_} = $subname = $nextsubname++;

		$cases .= <<"EDQ"; # header is funny to make everything elsif's
sub $subname {
	LOOP: {
		if (0) { ; }
EDQ
		while (@_) {
			($pattern,$action) = splice(@_,0,2);
			if ($pattern =~ /^eof$/i) {
				$cases .= <<"EDQ";
		elsif (\$eof) {
	 		package $caller;
			$action;
		}
EDQ
				$eof = 0;
			} elsif ($pattern =~ /^timeout$/i) {
			$cases .= <<"EDQ";
		elsif (\$timeout) {
		 	package $caller;
			$action;
		}
EDQ
				$timeout = 0;
			} else {
				$pattern =~ s#/#\\/#g;
			$cases .= <<"EDQ";
		elsif (\$S =~ /$pattern/) {
			\$S = \$';
		 	package $caller;
			$action;
		}
EDQ
			}
		}
		$cases .= <<"EDQ" if $eof;
		elsif (\$eof) {
			undef;
		}
EDQ
		$cases .= <<"EDQ" if $timeout;
		elsif (\$timeout) {
			undef;
		}
EDQ
		$cases .= <<'ESQ';
		else {
			$rmask = "";
			vec($rmask,fileno(S),1) = 1;
			($nfound, $rmask) =
		 		select($rmask, undef, undef, $endtime - time);
			if ($nfound) {
				$nread = sysread(S, $thisbuf, 1024);
				if ($nread > 0) {
					$S .= $thisbuf;
				} else {
					$eof++, redo LOOP; # any error is also eof
				}
			} else {
				$timeout++, redo LOOP; # timeout
			}
			redo LOOP;
		}
	}
}
ESQ
		eval $cases; die "$cases:\n$@" if $@;
	}
	$eof = $timeout = 0;
	do $subname();
}

## &chat'print([$handle,] @data)
## $handle is from previous &chat'open().
## like print $handle @data

sub print { ## public
	if ($_[0] =~ /$nextpat/) {
		*S = shift;
	}

	local $out = join $, , @_;
	syswrite(S, $out, length $out);
	if( $chat'debug ){
		print STDERR "printed:";
		print STDERR @_;
	}
}

## &chat'close([$handle,])
## $handle is from previous &chat'open().
## like close $handle

sub close { ## public
	if ($_[0] =~ /$nextpat/) {
	 	*S = shift;
	}
	close(S);
	if (defined $S{"needs_close"}) { # is it a listen socket?
		local(*NS) = $S{"needs_close"};
		delete $S{"needs_close"};
		close(NS);
	}
}

## @ready_handles = &chat'select($timeout, @handles)
## select()'s the handles with a timeout value of $timeout seconds.
## Returns an array of handles that are ready for I/O.
## Both user handles and chat handles are supported (but beware of
## stdio's buffering for user handles).

sub select { ## public
	local($timeout) = shift;
	local(@handles) = @_;
	local(%handlename) = ();
	local(%ready) = ();
	local($caller) = caller;
	local($rmask) = "";
	for (@handles) {
		if (/$nextpat/o) { # one of ours... see if ready
			local(*SYM) = $_;
			if (length($SYM)) {
				$timeout = 0; # we have a winner
				$ready{$_}++;
			}
			$handlename{fileno($_)} = $_;
		} else {
			$handlename{fileno(/'/ ? $_ : "$caller\'$_")} = $_;
		}
	}
	for (sort keys %handlename) {
		vec($rmask, $_, 1) = 1;
	}
	select($rmask, undef, undef, $timeout);
	for (sort keys %handlename) {
		$ready{$handlename{$_}}++ if vec($rmask,$_,1);
	}
	sort keys %ready;
}

# ($pty,$tty) = $chat'_getpty(PTY,TTY):
# internal procedure to get the next available pty.
# opens pty on handle PTY, and matching tty on handle TTY.
# returns undef if can't find a pty.
# Modify "/dev/pty" to "/dev/pts" for Dell Unix v2.2 (aka SVR4.04). Joe Doupnik.

sub _getpty { ## private
	local($_PTY,$_TTY) = @_;
	$_PTY =~ s/^([^']+)$/(caller)[$[]."'".$1/e;
	$_TTY =~ s/^([^']+)$/(caller)[$[]."'".$1/e;
	local($pty, $tty, $kind);
	if( -e "/dev/pts000" ){		## mods by Joe Doupnik Dec 1992
		$kind = "pts";		## SVR4 Streams
	} else {
		$kind = "pty";		## BSD Clist stuff
	}
	for $bank (112..127) {
		next unless -e sprintf("/dev/$kind%c0", $bank);
		for $unit (48..57) {
			$pty = sprintf("/dev/$kind%c%c", $bank, $unit);
			open($_PTY,"+>$pty") || next;
			select((select($_PTY), $| = 1)[0]);
			($tty = $pty) =~ s/pty/tty/;
			open($_TTY,"+>$tty") || next;
			select((select($_TTY), $| = 1)[0]);
			system "stty nl>$tty";
			return ($pty,$tty);
		}
	}
	undef;
}

1;
Commit	Line	Data
3e3baf6d	1	# chat.pl: chat with a server
a6d71656 GS	2	#
	3	# This library is no longer being maintained, and is included for backward
	4	# compatibility with Perl 4 programs which may require it.
	5	#
	6	# In particular, this should not be used as an example of modern Perl
	7	# programming techniques.
	8	#
	9	# Suggested alternative: Socket
	10	#
3e3baf6d TB	11	# Based on: V2.01.alpha.7 91/06/16
	12	# Randal L. Schwartz (was <merlyn@stonehenge.com>)
	13	# multihome additions by A.Macpherson@bnr.co.uk
	14	# allow for /dev/pts based systems by Joe Doupnik <JRD@CC.USU.EDU>
	15
	16	package chat;
	17
	18	require 'sys/socket.ph';
	19
	20	if( defined( &main'PF_INET ) ){
	21	$pf_inet = &main'PF_INET;
	22	$sock_stream = &main'SOCK_STREAM;
	23	local($name, $aliases, $proto) = getprotobyname( 'tcp' );
	24	$tcp_proto = $proto;
	25	}
	26	else {
	27	# XXX hardwired $PF_INET, $SOCK_STREAM, 'tcp'
	28	# but who the heck would change these anyway? (:-)
	29	$pf_inet = 2;
	30	$sock_stream = 1;
	31	$tcp_proto = 6;
	32	}
	33
	34
	35	$sockaddr = 'S n a4 x8';
	36	chop($thishost = `hostname`);
	37
	38	# S = symbol for current I/O, gets assigned chatsymbol....
	39	$next = "chatsymbol000000"; # next one
	40	$nextpat = "^chatsymbol"; # patterns that match next++, ++, ++, ++
	41
	42
	43	## $handle = &chat'open_port("server.address",$port_number);
	44	## opens a named or numbered TCP server
	45
	46	sub open_port { ## public
	47	local($server, $port) = @_;
	48
	49	local($serveraddr,$serverproc);
	50
	51	# We may be multi-homed, start with 0, fixup once connexion is made
	52	$thisaddr = "\0\0\0\0" ;
	53	$thisproc = pack($sockaddr, 2, 0, $thisaddr);
	54
	55	*S = ++$next;
	56	if ($server =~ /^(\d+)+\.(\d+)\.(\d+)\.(\d+)$/) {
	57	$serveraddr = pack('C4', $1, $2, $3, $4);
	58	} else {
	59	local(@x) = gethostbyname($server);
	60	return undef unless @x;
	61	$serveraddr = $x[4];
	62	}
	63	$serverproc = pack($sockaddr, 2, $port, $serveraddr);
	64	unless (socket(S, $pf_inet, $sock_stream, $tcp_proto)) {
	65	($!) = ($!, close(S)); # close S while saving $!
	66	return undef;
	67	}
	68	unless (bind(S, $thisproc)) {
	69	($!) = ($!, close(S)); # close S while saving $!
	70	return undef;
	71	}
	72	unless (connect(S, $serverproc)) {
	73	($!) = ($!, close(S)); # close S while saving $!
	74	return undef;
75	}
76	# We opened with the local address set to ANY, at this stage we know
77	# which interface we are using. This is critical if our machine is
78	# multi-homed, with IP forwarding off, so fix-up.
79	local($fam,$lport);
80	($fam,$lport,$thisaddr) = unpack($sockaddr, getsockname(S));
81	$thisproc = pack($sockaddr, 2, 0, $thisaddr);
82	# end of post-connect fixup
83	select((select(S), $\| = 1)[0]);
84	$next; # return symbol for switcharound
85	}
86
87	## ($host, $port, $handle) = &chat'open_listen([$port_number]);
88	## opens a TCP port on the current machine, ready to be listened to
89	## if $port_number is absent or zero, pick a default port number
90	## process must be uid 0 to listen to a low port number
91
92	sub open_listen { ## public
93
94	*S = ++$next;
95	local($thisport) = shift \|\| 0;
96	local($thisproc_local) = pack($sockaddr, 2, $thisport, $thisaddr);
97	local(*NS) = "__" . time;
98	unless (socket(NS, $pf_inet, $sock_stream, $tcp_proto)) {
99	($!) = ($!, close(NS));
100	return undef;
101	}
102	unless (bind(NS, $thisproc_local)) {
103	($!) = ($!, close(NS));
104	return undef;
105	}
106	unless (listen(NS, 1)) {
107	($!) = ($!, close(NS));
108	return undef;
109	}
110	select((select(NS), $\| = 1)[0]);
111	local($family, $port, @myaddr) =
112	unpack("S n C C C C x8", getsockname(NS));
113	$S{"needs_accept"} = *NS; # so expect will open it
114	(@myaddr, $port, $next); # returning this
115	}
116
117	## $handle = &chat'open_proc("command","arg1","arg2",...);
118	## opens a /bin/sh on a pseudo-tty
119
120	sub open_proc { ## public
121	local(@cmd) = @_;
122
123	*S = ++$next;
124	local(*TTY) = "__TTY" . time;
125	local($pty,$tty) = &_getpty(S,TTY);
126	die "Cannot find a new pty" unless defined $pty;
127	$pid = fork;
128	die "Cannot fork: $!" unless defined $pid;
129	unless ($pid) {
130	close STDIN; close STDOUT; close STDERR;
131	setpgrp(0,$$);
132	if (open(DEVTTY, "/dev/tty")) {
133	ioctl(DEVTTY,0x20007471,0); # XXX s/b &TIOCNOTTY
134	close DEVTTY;
135	}
136	open(STDIN,"<&TTY");
137	open(STDOUT,">&TTY");
138	open(STDERR,">&STDOUT");
139	die "Oops" unless fileno(STDERR) == 2; # sanity
140	close(S);
141	exec @cmd;
142	die "Cannot exec @cmd: $!";
143	}
144	close(TTY);
145	$next; # return symbol for switcharound
146	}
147
148	# $S is the read-ahead buffer
149
150	## $return = &chat'expect([$handle,] $timeout_time,
151	## $pat1, $body1, $pat2, $body2, ... )
152	## $handle is from previous &chat'open_*().
153	## $timeout_time is the time (either relative to the current time, or
154	## absolute, ala time(2)) at which a timeout event occurs.
155	## $pat1, $pat2, and so on are regexs which are matched against the input
156	## stream. If a match is found, the entire matched string is consumed,
157	## and the corresponding body eval string is evaled.
158	##
159	## Each pat is a regular-expression (probably enclosed in single-quotes
160	## in the invocation). ^ and $ will work, respecting the current value of $*.
161	## If pat is 'TIMEOUT', the body is executed if the timeout is exceeded.
162	## If pat is 'EOF', the body is executed if the process exits before
163	## the other patterns are seen.
164	##
165	## Pats are scanned in the order given, so later pats can contain
166	## general defaults that won't be examined unless the earlier pats
167	## have failed.
168	##
169	## The result of eval'ing body is returned as the result of
170	## the invocation. Recursive invocations are not thought
171	## through, and may work only accidentally. :-)
172	##
173	## undef is returned if either a timeout or an eof occurs and no
174	## corresponding body has been defined.
175	## I/O errors of any sort are treated as eof.
176
177	$nextsubname = "expectloop000000"; # used for subroutines
178
179	sub expect { ## public
180	if ($_[0] =~ /$nextpat/) {
181	*S = shift;
182	}
183	local($endtime) = shift;
184
185	local($timeout,$eof) = (1,1);
186	local($caller) = caller;
187	local($rmask, $nfound, $timeleft, $thisbuf);
188	local($cases, $pattern, $action, $subname);
189	$endtime += time if $endtime < 600_000_000;
190
191	if (defined $S{"needs_accept"}) { # is it a listen socket?
192	local(*NS) = $S{"needs_accept"};
193	delete $S{"needs_accept"};
194	$S{"needs_close"} = *NS;
195	unless(accept(S,NS)) {
196	($!) = ($!, close(S), close(NS));
197	return undef;
198	}
199	select((select(S), $\| = 1)[0]);
200	}
201
202	# now see whether we need to create a new sub:
203
204	unless ($subname = $expect_subname{$caller,@_}) {
205	# nope. make a new one:
206	$expect_subname{$caller,@_} = $subname = $nextsubname++;
207
208	$cases .= <<"EDQ"; # header is funny to make everything elsif's
209	sub $subname {
210	LOOP: {
211	if (0) { ; }
212	EDQ
213	while (@_) {
214	($pattern,$action) = splice(@_,0,2);
215	if ($pattern =~ /^eof$/i) {
216	$cases .= <<"EDQ";
217	elsif (\$eof) {
218	package $caller;
219	$action;
220	}
221	EDQ
222	$eof = 0;
223	} elsif ($pattern =~ /^timeout$/i) {
224	$cases .= <<"EDQ";
225	elsif (\$timeout) {
226	package $caller;
227	$action;
228	}
229	EDQ
230	$timeout = 0;
231	} else {
232	$pattern =~ s#/#\\/#g;
233	$cases .= <<"EDQ";
234	elsif (\$S =~ /$pattern/) {
235	\$S = \$';
236	package $caller;
237	$action;
238	}
239	EDQ
240	}
241	}
242	$cases .= <<"EDQ" if $eof;
243	elsif (\$eof) {
244	undef;
245	}
246	EDQ
247	$cases .= <<"EDQ" if $timeout;
248	elsif (\$timeout) {
249	undef;
250	}
251	EDQ
252	$cases .= <<'ESQ';
253	else {
254	$rmask = "";
255	vec($rmask,fileno(S),1) = 1;
256	($nfound, $rmask) =
257	select($rmask, undef, undef, $endtime - time);
258	if ($nfound) {
259	$nread = sysread(S, $thisbuf, 1024);
260	if ($nread > 0) {
261	$S .= $thisbuf;
262	} else {
263	$eof++, redo LOOP; # any error is also eof
264	}
265	} else {
266	$timeout++, redo LOOP; # timeout
267	}
268	redo LOOP;
269	}
270	}
271	}
272	ESQ
273	eval $cases; die "$cases:\n$@" if $@;
274	}
275	$eof = $timeout = 0;
276	do $subname();
277	}
278
279	## &chat'print([$handle,] @data)
280	## $handle is from previous &chat'open().
281	## like print $handle @data
282
283	sub print { ## public
284	if ($_[0] =~ /$nextpat/) {
285	*S = shift;
286	}
b7b1864f CB	287
	288	local $out = join $, , @_;
	289	syswrite(S, $out, length $out);
3e3baf6d TB	290	if( $chat'debug ){
	291	print STDERR "printed:";
	292	print STDERR @_;
	293	}
	294	}
	295
	296	## &chat'close([$handle,])
	297	## $handle is from previous &chat'open().
	298	## like close $handle
	299
	300	sub close { ## public
	301	if ($_[0] =~ /$nextpat/) {
	302	*S = shift;
	303	}
	304	close(S);
	305	if (defined $S{"needs_close"}) { # is it a listen socket?
	306	local(*NS) = $S{"needs_close"};
	307	delete $S{"needs_close"};
	308	close(NS);
	309	}
	310	}
	311
	312	## @ready_handles = &chat'select($timeout, @handles)
	313	## select()'s the handles with a timeout value of $timeout seconds.
	314	## Returns an array of handles that are ready for I/O.
	315	## Both user handles and chat handles are supported (but beware of
	316	## stdio's buffering for user handles).
	317
	318	sub select { ## public
	319	local($timeout) = shift;
	320	local(@handles) = @_;
	321	local(%handlename) = ();
	322	local(%ready) = ();
	323	local($caller) = caller;
	324	local($rmask) = "";
	325	for (@handles) {
	326	if (/$nextpat/o) { # one of ours... see if ready
	327	local(*SYM) = $_;
	328	if (length($SYM)) {
	329	$timeout = 0; # we have a winner
	330	$ready{$_}++;
	331	}
	332	$handlename{fileno($_)} = $_;
	333	} else {
	334	$handlename{fileno(/'/ ? $_ : "$caller\'$_")} = $_;
	335	}
	336	}
	337	for (sort keys %handlename) {
	338	vec($rmask, $_, 1) = 1;
	339	}
	340	select($rmask, undef, undef, $timeout);
	341	for (sort keys %handlename) {
	342	$ready{$handlename{$_}}++ if vec($rmask,$_,1);
	343	}
	344	sort keys %ready;
	345	}
	346
	347	# ($pty,$tty) = $chat'_getpty(PTY,TTY):
	348	# internal procedure to get the next available pty.
	349	# opens pty on handle PTY, and matching tty on handle TTY.
	350	# returns undef if can't find a pty.
	351	# Modify "/dev/pty" to "/dev/pts" for Dell Unix v2.2 (aka SVR4.04). Joe Doupnik.
	352
	353	sub _getpty { ## private
354	local($_PTY,$_TTY) = @_;
355	$_PTY =~ s/^([^']+)$/(caller)[$[]."'".$1/e;
356	$_TTY =~ s/^([^']+)$/(caller)[$[]."'".$1/e;
357	local($pty, $tty, $kind);
358	if( -e "/dev/pts000" ){ ## mods by Joe Doupnik Dec 1992
359	$kind = "pts"; ## SVR4 Streams
360	} else {
361	$kind = "pty"; ## BSD Clist stuff
362	}
363	for $bank (112..127) {
364	next unless -e sprintf("/dev/$kind%c0", $bank);
365	for $unit (48..57) {
366	$pty = sprintf("/dev/$kind%c%c", $bank, $unit);
367	open($_PTY,"+>$pty") \|\| next;
368	select((select($_PTY), $\| = 1)[0]);
369	($tty = $pty) =~ s/pty/tty/;
370	open($_TTY,"+>$tty") \|\| next;
371	select((select($_TTY), $\| = 1)[0]);
372	system "stty nl>$tty";
373	return ($pty,$tty);
374	}
375	}
376	undef;
377	}
378
379	1;