lib/perl5/5.6.1/chat2.pl

   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
  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         }
 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 $handle
 299
 300 sub close { ## public
 301         if ($_[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;