1# chat.pl: chat with a server
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#
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
16package chat;
17
18require 'sys/socket.ph';
19
20if( 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}
26else {
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';
36chop($thishost = `hostname`);
37
38# *S = symbol for current I/O, gets assigned *chatsymbol....
39$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
46sub 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 $port_number is absent or zero, pick a default port number
90## process must be uid 0 to listen to a low port number
91
92sub open_listen { ## public
93
94	*S = ++$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## $handle = &chat'open_proc("command","arg1","arg2",...);
118## opens a /bin/sh on a pseudo-tty
119
120sub open_proc { ## public
121	local(@cmd) = @_;
122
123	*S = ++$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
179sub 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
209sub $subname {
210	LOOP: {
211		if (0) { ; }
212EDQ
213		while (@_) {
214			($pattern,$action) = splice(@_,0,2);
215			if ($pattern =~ /^eof$/i) {
216				$cases .= <<"EDQ";
217		elsif (\$eof) {
218	 		package $caller;
219			$action;
220		}
221EDQ
222				$eof = 0;
223			} elsif ($pattern =~ /^timeout$/i) {
224			$cases .= <<"EDQ";
225		elsif (\$timeout) {
226		 	package $caller;
227			$action;
228		}
229EDQ
230				$timeout = 0;
231			} else {
232				$pattern =~ s#/#\\/#g;
233			$cases .= <<"EDQ";
234		elsif (\$S =~ /$pattern/) {
235			\$S = \$';
236		 	package $caller;
237			$action;
238		}
239EDQ
240			}
241		}
242		$cases .= <<"EDQ" if $eof;
243		elsif (\$eof) {
244			undef;
245		}
246EDQ
247		$cases .= <<"EDQ" if $timeout;
248		elsif (\$timeout) {
249			undef;
250		}
251EDQ
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}
272ESQ
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 $handle @data
282
283sub print { ## public
284	if ($_[0] =~ /$nextpat/) {
285		*S = shift;
286	}
287
288	local $out = join $, , @_;
289	syswrite(S, $out, length $out);
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 $handle
299
300sub close { ## public
301	if ($_[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 $timeout seconds.
314## Returns an array of handles that are ready for I/O.
315## Both user handles and chat handles are supported (but beware of
316## stdio's buffering for user handles).
317
318sub select { ## public
319	local($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) = $chat'_getpty(PTY,TTY):
348# internal procedure to get the next available pty.
349# opens pty on handle PTY, and matching tty on handle TTY.
350# returns undef if can't find a pty.
351# Modify "/dev/pty" to "/dev/pts" for Dell Unix v2.2 (aka SVR4.04). Joe Doupnik.
352
353sub _getpty { ## private
354	local($_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
3791;
380