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Diffstat (limited to 'scripts/expn.1')
| -rw-r--r-- | scripts/expn.1 | 1369 |
1 files changed, 1369 insertions, 0 deletions
diff --git a/scripts/expn.1 b/scripts/expn.1 new file mode 100644 index 000000000000..f316247b4a9c --- /dev/null +++ b/scripts/expn.1 @@ -0,0 +1,1369 @@ +#!@PERL@ +'di '; +'ds 00 \\"'; +'ig 00 '; +# +# THIS PROGRAM IS ITS OWN MANUAL PAGE. INSTALL IN man & bin. +# + +# hardcoded constants, should work fine for BSD-based systems +#require 'sys/socket.ph'; # perl 4 +use Socket; # perl 5 +$AF_INET = &AF_INET; +$SOCK_STREAM = &SOCK_STREAM; +$sockaddr = 'S n a4 x8'; + +# system requirements: +# must have 'nslookup' and 'hostname' programs. + +# $Header: /home/cvsroot/am-utils/scripts/expn.1,v 1.4 2003/07/18 15:17:37 ezk Exp $ + +# TODO: +# less magic should apply to command-line addresses +# less magic should apply to local addresses +# add magic to deal with cross-domain cnames + +# Checklist: (hard addresses) +# 250 Kimmo Suominen <"|/usr/local/mh/lib/slocal -user kim"@grendel.tac.nyc.ny.us> +# harry@hofmann.cs.Berkeley.EDU -> harry@tenet (.berkeley.edu) [dead] +# bks@cs.berkeley.edu -> shiva.CS (.berkeley.edu) [dead] +# dan@tc.cornell.edu -> brown@tiberius (.tc.cornell.edu) + +############################################################################# +# +# Copyright (c) 1993 David Muir Sharnoff +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions +# are met: +# 1. Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# 2. Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# 3. All advertising materials mentioning features or use of this software +# must display the following acknowledgment: +# This product includes software developed by the David Muir Sharnoff. +# 4. The name of David Sharnoff may not be used to endorse or promote products +# derived from this software without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE DAVID MUIR SHARNOFF ``AS IS'' AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +# ARE DISCLAIMED. IN NO EVENT SHALL DAVID MUIR SHARNOFF BE LIABLE +# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. +# +# This copyright notice derived from material copyrighted by the Regents +# of the University of California. +# +# Contributions accepted. +# +############################################################################# + +# overall structure: +# in an effort to not trace each address individually, but rather +# ask each server in turn a whole bunch of questions, addresses to +# be expanded are queued up. +# +# This means that all accounting w.r.t. an address must be stored in +# various arrays. Generally these arrays are indexed by the +# string "$addr *** $server" where $addr is the address to be +# expanded "foo" or maybe "foo@bar" and $server is the hostname +# of the SMTP server to contact. +# + +# important global variables: +# +# @hosts : list of servers still to be contacted +# $server : name of the current we are currently looking at +# @users = $users{@hosts[0]} : addresses to expand at this server +# $u = $users[0] : the current address being expanded +# $names{"$users[0] *** $server"} : the 'name' associated with the address +# $mxbacktrace{"$users[0] *** $server"} : record of mx expansion +# $mx_secondary{$server} : other mx relays at the same priority +# $domainify_fallback{"$users[0] *** $server"} : alternative names to try +# instead of $server if $server doesn't work +# $temporary_redirect{"$users[0] *** $server"} : when trying alternates, +# temporarily channel all tries along current path +# $giveup{$server} : do not bother expanding addresses at $server +# $verbose : -v +# $watch : -w +# $vw : -v or -w +# $debug : -d +# $valid : -a +# $levels : -1 +# S : the socket connection to $server + +$have_nslookup = 1; # we have the nslookup program +$port = 'smtp'; +$av0 = $0; +$ENV{'PATH'} .= ":/usr/etc" unless $ENV{'PATH'} =~ m,/usr/etc,; +$ENV{'PATH'} .= ":/usr/ucb" unless $ENV{'PATH'} =~ m,/usr/ucb,; +select(STDERR); + +$0 = "$av0 - running hostname"; +chop($name = `hostname || uname -n`); + +$0 = "$av0 - lookup host FQDN and IP addr"; +($hostname,$aliases,$type,$len,$thisaddr) = gethostbyname($name); + +$0 = "$av0 - parsing args"; +$usage = "Usage: $av0 [-1avwd] user[\@host] [user2[host2] ...]"; +for $a (@ARGV) { + die $usage if $a eq "-"; + while ($a =~ s/^(-.*)([1avwd])/$1/) { + eval '$'."flag_$2 += 1"; + } + next if $a eq "-"; + die $usage if $a =~ /^-/; + &expn(&parse($a,$hostname,undef,1)); +} +$verbose = $flag_v; +$watch = $flag_w; +$vw = $flag_v + $flag_w; +$debug = $flag_d; +$valid = $flag_a; +$levels = $flag_1; + +die $usage unless @hosts; +if ($valid) { + if ($valid == 1) { + $validRequirement = 0.8; + } elsif ($valid == 2) { + $validRequirement = 1.0; + } elsif ($valid == 3) { + $validRequirement = 0.9; + } else { + $validRequirement = (1 - (1/($valid-3))); + print "validRequirement = $validRequirement\n" if $debug; + } +} + +$0 = "$av0 - building local socket"; +($name,$aliases,$proto) = getprotobyname('tcp'); +($name,$aliases,$port) = getservbyname($port,'tcp') + unless $port =~ /^\d+/; +$this = pack($sockaddr, &AF_INET, 0, $thisaddr); + +HOST: +while (@hosts) { + $server = shift(@hosts); + @users = split(' ',$users{$server}); + delete $users{$server}; + + # is this server already known to be bad? + $0 = "$av0 - looking up $server"; + if ($giveup{$server}) { + &giveup('mx domainify',$giveup{$server}); + next; + } + + # do we already have an mx record for this host? + next HOST if &mxredirect($server,*users); + + # look it up, or try for an mx. + $0 = "$av0 - gethostbyname($server)"; + + ($name,$aliases,$type,$len,$thataddr) = gethostbyname($server); + # if we can't get an A record, try for an MX record. + unless($thataddr) { + &mxlookup(1,$server,"$server: could not resolve name",*users); + next HOST; + } + + # get a connection, or look for an mx + $0 = "$av0 - socket to $server"; + $that = pack($sockaddr, &AF_INET, $port, $thataddr); + socket(S, &AF_INET, &SOCK_STREAM, $proto) + || die "socket: $!"; + $0 = "$av0 - bind to $server"; + bind(S, $this) + || die "bind $hostname,0: $!"; + $0 = "$av0 - connect to $server"; + print "debug = $debug server = $server\n" if $debug > 8; + if (! connect(S, $that) || ($debug == 10 && $server =~ /relay\d.UU.NET$/i)) { + $0 = "$av0 - $server: could not connect: $!\n"; + $emsg = $!; + unless (&mxlookup(0,$server,"$server: could not connect: $!",*users)) { + &giveup('mx',"$server: Could not connect: $emsg"); + } + next HOST; + } + select((select(S),$| = 1)[0]); # don't buffer output to S + + # read the greeting + $0 = "$av0 - talking to $server"; + &alarm("greeting with $server",''); + while(<S>) { + alarm(0); + print if $watch; + if (/^(\d+)([- ])/) { + if ($1 != 220) { + $0 = "$av0 - bad numeric response from $server"; + &alarm("giving up after bad response from $server",''); + &read_response($2,$watch); + alarm(0); + print STDERR "$server: NOT 220 greeting: $_" + if ($debug || $vw); + if (&mxlookup(0,$server,"$server: did not respond with a 220 greeting",*users)) { + close(S); + next HOST; + } + } + last if ($2 eq " "); + } else { + $0 = "$av0 - bad response from $server"; + print STDERR "$server: NOT 220 greeting: $_" + if ($debug || $vw); + unless (&mxlookup(0,$server,"$server: did not respond with SMTP codes",*users)) { + &giveup('',"$server: did not talk SMTP"); + } + close(S); + next HOST; + } + &alarm("greeting with $server",''); + } + alarm(0); + + # if this causes problems, remove it + $0 = "$av0 - sending helo to $server"; + &alarm("sending helo to $server",""); + &ps("helo $hostname"); + while(<S>) { + print if $watch; + last if /^\d+ /; + } + alarm(0); + + # try the users, one by one + USER: + while(@users) { + $u = shift(@users); + $0 = "$av0 - expanding $u [\@$server]"; + + # do we already have a name for this user? + $oldname = $names{"$u *** $server"}; + + print &compact($u,$server)." ->\n" if ($verbose && ! $valid); + if ($valid) { + # + # when running with -a, we delay taking any action + # on the results of our query until we have looked + # at the complete output. @toFinal stores expansions + # that will be final if we take them. @toExpn stores + # expansions that are not final. @isValid keeps + # track of our ability to send mail to each of the + # expansions. + # + @isValid = (); + @toFinal = (); + @toExpn = (); + } + +# ($ecode,@expansion) = &expn_vrfy($u,$server); + (@foo) = &expn_vrfy($u,$server); + ($ecode,@expansion) = @foo; + if ($ecode) { + &giveup('',$ecode,$u); + last USER; + } + + for $s (@expansion) { + $s =~ s/[\n\r]//g; + $0 = "$av0 - parsing $server: $s"; + + $skipwatch = $watch; + + if ($s =~ /^[25]51([- ]).*<(.+)>/) { + print "$s" if $watch; + print "(pretending 250$1<$2>)" if ($debug && $watch); + print "\n" if $watch; + $s = "250$1<$2>"; + $skipwatch = 0; + } + + if ($s =~ /^250([- ])(.+)/) { + print "$s\n" if $skipwatch; + ($done,$addr) = ($1,$2); + ($newhost, $newaddr, $newname) = &parse($addr,$server,$oldname, $#expansion == 0); + print "($newhost, $newaddr, $newname) = &parse($addr, $server, $oldname)\n" if $debug; + if (! $newhost) { + # no expansion is possible w/o a new server to call + if ($valid) { + push(@isValid, &validAddr($newaddr)); + push(@toFinal,$newaddr,$server,$newname); + } else { + &verbose(&final($newaddr,$server,$newname)); + } + } else { + $newmxhost = &mx($newhost,$newaddr); + print "$newmxhost = &mx($newhost)\n" + if ($debug && $newhost ne $newmxhost); + $0 = "$av0 - parsing $newaddr [@$newmxhost]"; + print "levels = $levels, level{$u *** $server} = ".$level{"$u *** $server"}."\n" if ($debug > 1); + # If the new server is the current one, + # it would have expanded things for us + # if it could have. Mx records must be + # followed to compare server names. + # We are also done if the recursion + # count has been exceeded. + if (&trhost($newmxhost) eq &trhost($server) || ($levels && $level{"$u *** $server"} >= $levels)) { + if ($valid) { + push(@isValid, &validAddr($newaddr)); + push(@toFinal,$newaddr,$newmxhost,$newname); + } else { + &verbose(&final($newaddr,$newmxhost,$newname)); + } + } else { + # more work to do... + if ($valid) { + push(@isValid, &validAddr($newaddr)); + push(@toExpn,$newmxhost,$newaddr,$newname,$level{"$u *** $server"}); + } else { + &verbose(&expn($newmxhost,$newaddr,$newname,$level{"$u *** $server"})); + } + } + } + last if ($done eq " "); + next; + } + # 550 is a known code... Should the be + # included in -a output? Might be a bug + # here. Does it matter? Can assume that + # there won't be UNKNOWN USER responses + # mixed with valid users? + if ($s =~ /^(550)([- ])/) { + if ($valid) { + print STDERR "\@$server:$u ($oldname) USER UNKNOWN\n"; + } else { + &verbose(&final($u,$server,$oldname,"USER UNKNOWN")); + } + last if ($2 eq " "); + next; + } + # 553 is a known code... + if ($s =~ /^(553)([- ])/) { + if ($valid) { + print STDERR "\@$server:$u ($oldname) USER AMBIGUOUS\n"; + } else { + &verbose(&final($u,$server,$oldname,"USER AMBIGUOUS")); + } + last if ($2 eq " "); + next; + } + # 252 is a known code... + if ($s =~ /^(252)([- ])/) { + if ($valid) { + print STDERR "\@$server:$u ($oldname) REFUSED TO VRFY\n"; + } else { + &verbose(&final($u,$server,$oldname,"REFUSED TO VRFY")); + } + last if ($2 eq " "); + next; + } + &giveup('',"$server: did not grok '$s'",$u); + last USER; + } + + if ($valid) { + # + # now we decide if we are going to take these + # expansions or roll them back. + # + $avgValid = &average(@isValid); + print "avgValid = $avgValid\n" if $debug; + if ($avgValid >= $validRequirement) { + print &compact($u,$server)." ->\n" if $verbose; + while (@toExpn) { + &verbose(&expn(splice(@toExpn,0,4))); + } + while (@toFinal) { + &verbose(&final(splice(@toFinal,0,3))); + } + } else { + print "Tossing some valid to avoid invalid ".&compact($u,$server)."\n" if ($avgValid > 0.0 && ($vw || $debug)); + print &compact($u,$server)." ->\n" if $verbose; + &verbose(&final($u,$server,$newname)); + } + } + } + + &alarm("sending 'quit' to $server",''); + $0 = "$av0 - sending 'quit' to $server"; + &ps("quit"); + while(<S>) { + print if $watch; + last if /^\d+ /; + } + close(S); + alarm(0); +} + +$0 = "$av0 - printing final results"; +print "----------\n" if $vw; +select(STDOUT); +for $f (sort @final) { + print "$f\n"; +} +unlink("/tmp/expn$$"); +exit(0); + + +# abandon all attempts deliver to $server +# register the current addresses as the final ones +sub giveup +{ + local($redirect_okay,$reason,$user) = @_; + local($us,@so,$nh,@remaining_users); + local($pk,$file,$line); + ($pk, $file, $line) = caller; + + $0 = "$av0 - giving up on $server: $reason"; + # + # add back a user if we gave up in the middle + # + push(@users,$user) if $user; + # + # don't bother with this system anymore + # + unless ($giveup{$server}) { + $giveup{$server} = $reason; + print STDERR "$reason\n"; + } + print "Giveup at $file:$line!!! redirect okay = $redirect_okay; $reason\n" if $debug; + # + # Wait! + # Before giving up, see if there is a chance that + # there is another host to redirect to! + # (Kids, don't do this at home! Hacking is a dangerous + # crime and you could end up behind bars.) + # + for $u (@users) { + if ($redirect_okay =~ /\bmx\b/) { + next if &try_fallback('mx',$u,*server, + *mx_secondary, + *already_mx_fellback); + } + if ($redirect_okay =~ /\bdomainify\b/) { + next if &try_fallback('domainify',$u,*server, + *domainify_fallback, + *already_domainify_fellback); + } + push(@remaining_users,$u); + } + @users = @remaining_users; + for $u (@users) { + print &compact($u,$server)." ->\n" if ($verbose && $valid && $u); + &verbose(&final($u,$server,$names{"$u *** $server"},$reason)); + } +} +# +# This routine is used only within &giveup. It checks to +# see if we really have to giveup or if there is a second +# chance because we did something before that can be +# backtracked. +# +# %fallback{"$user *** $host"} tracks what is able to fallback +# %fellback{"$user *** $host"} tracks what has fallen back +# +# If there is a valid backtrack, then queue up the new possibility +# +sub try_fallback +{ + local($method,$user,*host,*fall_table,*fellback) = @_; + local($us,$fallhost,$oldhost,$ft,$i); + + if ($debug > 8) { + print "Fallback table $method:\n"; + for $i (sort keys %fall_table) { + print "\t'$i'\t\t'$fall_table{$i}'\n"; + } + print "Fellback table $method:\n"; + for $i (sort keys %fellback) { + print "\t'$i'\t\t'$fellback{$i}'\n"; + } + print "U: $user H: $host\n"; + } + + $us = "$user *** $host"; + if (defined $fellback{$us}) { + # + # Undo a previous fallback so that we can try again + # Nested fallbacks are avoided because they could + # lead to infinite loops + # + $fallhost = $fellback{$us}; + print "Already $method fell back from $us -> \n" if $debug; + $us = "$user *** $fallhost"; + $oldhost = $fallhost; + } elsif (($method eq 'mx') && (defined $mxbacktrace{$us}) && (defined $mx_secondary{$mxbacktrace{$us}})) { + print "Fallback an MX expansion $us -> \n" if $debug; + $oldhost = $mxbacktrace{$us}; + } else { + print "Oldhost($host, $us) = " if $debug; + $oldhost = $host; + } + print "$oldhost\n" if $debug; + if (((defined $fall_table{$us}) && ($ft = $us)) || ((defined $fall_table{$oldhost}) && ($ft = $oldhost))) { + print "$method Fallback = ".$fall_table{$ft}."\n" if $debug; + local(@so,$newhost); + @so = split(' ',$fall_table{$ft}); + $newhost = shift(@so); + print "Falling back ($method) $us -> $newhost (from $oldhost)\n" if $debug; + if ($method eq 'mx') { + if (! defined ($mxbacktrace{"$user *** $newhost"})) { + if (defined $mxbacktrace{"$user *** $oldhost"}) { + print "resetting oldhost $oldhost to the original: " if $debug; + $oldhost = $mxbacktrace{"$user *** $oldhost"}; + print "$oldhost\n" if $debug; + } + $mxbacktrace{"$user *** $newhost"} = $oldhost; + print "mxbacktrace $user *** $newhost -> $oldhost\n" if $debug; + } + $mx{&trhost($oldhost)} = $newhost; + } else { + $temporary_redirect{$us} = $newhost; + } + if (@so) { + print "Can still $method $us: @so\n" if $debug; + $fall_table{$ft} = join(' ',@so); + } else { + print "No more fallbacks for $us\n" if $debug; + delete $fall_table{$ft}; + } + if (defined $create_host_backtrack{$us}) { + $create_host_backtrack{"$user *** $newhost"} + = $create_host_backtrack{$us}; + } + $fellback{"$user *** $newhost"} = $oldhost; + &expn($newhost,$user,$names{$us},$level{$us}); + return 1; + } + delete $temporary_redirect{$us}; + $host = $oldhost; + return 0; +} +# return 1 if you could send mail to the address as is. +sub validAddr +{ + local($addr) = @_; + $res = &do_validAddr($addr); + print "validAddr($addr) = $res\n" if $debug; + $res; +} +sub do_validAddr +{ + local($addr) = @_; + local($urx) = "[-A-Za-z_.0-9+]+"; + + # \u + return 0 if ($addr =~ /^\\/); + # ?@h + return 1 if ($addr =~ /.\@$urx$/); + # @h:? + return 1 if ($addr =~ /^\@$urx\:./); + # h!u + return 1 if ($addr =~ /^$urx!./); + # u + return 1 if ($addr =~ /^$urx$/); + # ? + print "validAddr($addr) = ???\n" if $debug; + return 0; +} +# Some systems use expn and vrfy interchangeably. Some only +# implement one or the other. Some check expn against mailing +# lists and vrfy against users. It doesn't appear to be +# consistent. +# +# So, what do we do? We try everything! +# +# +# Ranking of result codes: good: 250, 251/551, 252, 550, anything else +# +# Ranking of inputs: best: user@host.domain, okay: user +# +# Return value: $error_string, @responses_from_server +sub expn_vrfy +{ + local($u,$server) = @_; + local(@c) = ('expn', 'vrfy'); + local(@try_u) = $u; + local(@ret,$code); + + if (($u =~ /(.+)@(.+)/) && (&trhost($2) eq &trhost($server))) { + push(@try_u,$1); + } + + TRY: + for $c (@c) { + for $try_u (@try_u) { + &alarm("${c}'ing $try_u on $server",'',$u); + &ps("$c $try_u"); + alarm(0); + $s = <S>; + if ($s eq '') { + return "$server: lost connection"; + } + if ($s !~ /^(\d+)([- ])/) { + return "$server: garbled reply to '$c $try_u'"; + } + if ($1 == 250) { + $code = 250; + @ret = ("",$s); + push(@ret,&read_response($2,$debug)); + return (@ret); + } + if ($1 == 551 || $1 == 251) { + $code = $1; + @ret = ("",$s); + push(@ret,&read_response($2,$debug)); + next; + } + if ($1 == 252 && ($code == 0 || $code == 550)) { + $code = 252; + @ret = ("",$s); + push(@ret,&read_response($2,$watch)); + next; + } + if ($1 == 550 && $code == 0) { + $code = 550; + @ret = ("",$s); + push(@ret,&read_response($2,$watch)); + next; + } + &read_response($2,$watch); + } + } + return "$server: expn/vrfy not implemented" unless @ret; + return @ret; +} +# sometimes the old parse routine (now parse2) didn't +# reject funky addresses. +sub parse +{ + local($oldaddr,$server,$oldname,$one_to_one) = @_; + local($newhost, $newaddr, $newname, $um) = &parse2($oldaddr,$server,$oldname,$one_to_one); + if ($newaddr =~ m,^["/],) { + return (undef, $oldaddr, $newname) if $valid; + return (undef, $um, $newname); + } + return ($newhost, $newaddr, $newname); +} + +# returns ($new_smtp_server,$new_address,$new_name) +# given a response from a SMTP server ($newaddr), the +# current host ($server), the old "name" and a flag that +# indicates if it is being called during the initial +# command line parsing ($parsing_args) +sub parse2 +{ + local($newaddr,$context_host,$old_name,$parsing_args) = @_; + local(@names) = $old_name; + local($urx) = "[-A-Za-z_.0-9+]+"; + local($unmangle); + + # + # first, separate out the address part. + # + + # + # [NAME] <ADDR [(NAME)]> + # [NAME] <[(NAME)] ADDR + # ADDR [(NAME)] + # (NAME) ADDR + # [(NAME)] <ADDR> + # + if ($newaddr =~ /^\<(.*)\>$/) { + print "<A:$1>\n" if $debug; + ($newaddr) = &trim($1); + print "na = $newaddr\n" if $debug; + } + if ($newaddr =~ /^([^\<\>]*)\<([^\<\>]*)\>([^\<\>]*)$/) { + # address has a < > pair in it. + print "N:$1 <A:$2> N:$3\n" if $debug; + ($newaddr) = &trim($2); + unshift(@names, &trim($3,$1)); + print "na = $newaddr\n" if $debug; + } + if ($newaddr =~ /^([^\(\)]*)\(([^\(\)]*)\)([^\(\)]*)$/) { + # address has a ( ) pair in it. + print "A:$1 (N:$2) A:$3\n" if $debug; + unshift(@names,&trim($2)); + local($f,$l) = (&trim($1),&trim($3)); + if (($f && $l) || !($f || $l)) { + # address looks like: + # foo (bar) baz or (bar) + # not allowed! + print STDERR "Could not parse $newaddr\n" if $vw; + return(undef,$newaddr,&firstname(@names)); + } + $newaddr = $f if $f; + $newaddr = $l if $l; + print "newaddr now = $newaddr\n" if $debug; + } + # + # @foo:bar + # j%k@l + # a@b + # b!a + # a + # + $unmangle = $newaddr; + if ($newaddr =~ /^\@($urx)\:(.+)$/) { + print "(\@:)" if $debug; + # this is a bit of a cheat, but it seems necessary + return (&domainify($1,$context_host,$2),$2,&firstname(@names),$unmangle); + } + if ($newaddr =~ /^(.+)\@($urx)$/) { + print "(\@)" if $debug; + return (&domainify($2,$context_host,$newaddr),$newaddr,&firstname(@names),$unmangle); + } + if ($parsing_args) { + if ($newaddr =~ /^($urx)\!(.+)$/) { + return (&domainify($1,$context_host,$newaddr),$newaddr,&firstname(@names),$unmangle); + } + if ($newaddr =~ /^($urx)$/) { + return ($context_host,$newaddr,&firstname(@names),$unmangle); + } + print STDERR "Could not parse $newaddr\n"; + } + print "(?)" if $debug; + return(undef,$newaddr,&firstname(@names),$unmangle); +} +# return $u (@$server) unless $u includes reference to $server +sub compact +{ + local($u, $server) = @_; + local($se) = $server; + local($sp); + $se =~ s/(\W)/\\$1/g; + $sp = " (\@$server)"; + if ($u !~ /$se/i) { + return "$u$sp"; + } + return $u; +} +# remove empty (spaces don't count) members from an array +sub trim +{ + local(@v) = @_; + local($v,@r); + for $v (@v) { + $v =~ s/^\s+//; + $v =~ s/\s+$//; + push(@r,$v) if ($v =~ /\S/); + } + return(@r); +} +# using the host part of an address, and the server name, add the +# servers' domain to the address if it doesn't already have a +# domain. Since this sometimes fails, save a back reference so +# it can be unrolled. +sub domainify +{ + local($host,$domain_host,$u) = @_; + local($domain,$newhost); + + # cut of trailing dots + $host =~ s/\.$//; + $domain_host =~ s/\.$//; + + if ($domain_host !~ /\./) { + # + # domain host isn't, keep $host whatever it is + # + print "domainify($host,$domain_host) = $host\n" if $debug; + return $host; + } + + # + # There are several weird situations that need to be + # accounted for. They have to do with domain relay hosts. + # + # Examples: + # host server "right answer" + # + # shiva.cs cs.berkeley.edu shiva.cs.berkeley.edu + # shiva cs.berkeley.edu shiva.cs.berekley.edu + # cumulus reed.edu @reed.edu:cumulus.uucp + # tiberius tc.cornell.edu tiberius.tc.cornell.edu + # + # The first try must always be to cut the domain part out of + # the server and tack it onto the host. + # + # A reasonable second try is to tack the whole server part onto + # the host and for each possible repeated element, eliminate + # just that part. + # + # These extra "guesses" get put into the %domainify_fallback + # array. They will be used to give addresses a second chance + # in the &giveup routine + # + + local(%fallback); + + local($long); + $long = "$host $domain_host"; + $long =~ tr/A-Z/a-z/; + print "long = $long\n" if $debug; + if ($long =~ s/^([^ ]+\.)([^ ]+) \2(\.[^ ]+\.[^ ]+)/$1$2$3/) { + # matches shiva.cs cs.berkeley.edu and returns shiva.cs.berkeley.edu + print "condensed fallback $host $domain_host -> $long\n" if $debug; + $fallback{$long} = 9; + } + + local($fh); + $fh = $domain_host; + while ($fh =~ /\./) { + print "FALLBACK $host.$fh = 1\n" if $debug > 7; + $fallback{"$host.$fh"} = 1; + $fh =~ s/^[^\.]+\.//; + } + + $fallback{"$host.$domain_host"} = 2; + + ($domain = $domain_host) =~ s/^[^\.]+//; + $fallback{"$host$domain"} = 6 + if ($domain =~ /\./); + + if ($host =~ /\./) { + # + # Host is already okay, but let's look for multiple + # interpretations + # + print "domainify($host,$domain_host) = $host\n" if $debug; + delete $fallback{$host}; + $domainify_fallback{"$u *** $host"} = join(' ',sort {$fallback{$b} <=> $fallback{$a};} keys %fallback) if %fallback; + return $host; + } + + $domain = ".$domain_host" + if ($domain !~ /\..*\./); + $newhost = "$host$domain"; + + $create_host_backtrack{"$u *** $newhost"} = $domain_host; + print "domainify($host,$domain_host) = $newhost\n" if $debug; + delete $fallback{$newhost}; + $domainify_fallback{"$u *** $newhost"} = join(' ',sort {$fallback{$b} <=> $fallback{$a};} keys %fallback) if %fallback; + if ($debug) { + print "fallback = "; + print $domainify_fallback{"$u *** $newhost"} + if defined($domainify_fallback{"$u *** $newhost"}); + print "\n"; + } + return $newhost; +} +# return the first non-empty element of an array +sub firstname +{ + local(@names) = @_; + local($n); + while(@names) { + $n = shift(@names); + return $n if $n =~ /\S/; + } + return undef; +} +# queue up more addresses to expand +sub expn +{ + local($host,$addr,$name,$level) = @_; + if ($host) { + $host = &trhost($host); + + if (($debug > 3) || (defined $giveup{$host})) { + unshift(@hosts,$host) unless $users{$host}; + } else { + push(@hosts,$host) unless $users{$host}; + } + $users{$host} .= " $addr"; + $names{"$addr *** $host"} = $name; + $level{"$addr *** $host"} = $level + 1; + print "expn($host,$addr,$name)\n" if $debug; + return "\t$addr\n"; + } else { + return &final($addr,'NONE',$name); + } +} +# compute the numerical average value of an array +sub average +{ + local(@e) = @_; + return 0 unless @e; + local($e,$sum); + for $e (@e) { + $sum += $e; + } + $sum / @e; +} +# print to the server (also to stdout, if -w) +sub ps +{ + local($p) = @_; + print ">>> $p\n" if $watch; + print S "$p\n"; +} +# return case-adjusted name for a host (for comparison purposes) +sub trhost +{ + # treat foo.bar as an alias for Foo.BAR + local($host) = @_; + local($trhost) = $host; + $trhost =~ tr/A-Z/a-z/; + if ($trhost{$trhost}) { + $host = $trhost{$trhost}; + } else { + $trhost{$trhost} = $host; + } + $trhost{$trhost}; +} +# re-queue users if an mx record dictates a redirect +# don't allow a user to be redirected more than once +sub mxredirect +{ + local($server,*users) = @_; + local($u,$nserver,@still_there); + + $nserver = &mx($server); + + if (&trhost($nserver) ne &trhost($server)) { + $0 = "$av0 - mx redirect $server -> $nserver\n"; + for $u (@users) { + if (defined $mxbacktrace{"$u *** $nserver"}) { + push(@still_there,$u); + } else { + $mxbacktrace{"$u *** $nserver"} = $server; + print "mxbacktrace{$u *** $nserver} = $server\n" + if ($debug > 1); + &expn($nserver,$u,$names{"$u *** $server"}); + } + } + @users = @still_there; + if (! @users) { + return $nserver; + } else { + return undef; + } + } + return undef; +} +# follow mx records, return a hostname +# also follow temporary redirections coming from &domainify and +# &mxlookup +sub mx +{ + local($h,$u) = @_; + + for (;;) { + if (defined $mx{&trhost($h)} && $h ne $mx{&trhost($h)}) { + $0 = "$av0 - mx expand $h"; + $h = $mx{&trhost($h)}; + return $h; + } + if ($u) { + if (defined $temporary_redirect{"$u *** $h"}) { + $0 = "$av0 - internal redirect $h"; + print "Temporary redirect taken $u *** $h -> " if $debug; + $h = $temporary_redirect{"$u *** $h"}; + print "$h\n" if $debug; + next; + } + $htr = &trhost($h); + if (defined $temporary_redirect{"$u *** $htr"}) { + $0 = "$av0 - internal redirect $h"; + print "temporary redirect taken $u *** $h -> " if $debug; + $h = $temporary_redirect{"$u *** $htr"}; + print "$h\n" if $debug; + next; + } + } + return $h; + } +} +# look up mx records with the name server. +# re-queue expansion requests if possible +# optionally give up on this host. +sub mxlookup +{ + local($lastchance,$server,$giveup,*users) = @_; + local(*T); + local(*NSLOOKUP); + local($nh, $pref,$cpref); + local($o0) = $0; + local($nserver); + local($name,$aliases,$type,$len,$thataddr); + local(%fallback); + + return 1 if &mxredirect($server,*users); + + if ((defined $mx{$server}) || (! $have_nslookup)) { + return 0 unless $lastchance; + &giveup('mx domainify',$giveup); + return 0; + } + + $0 = "$av0 - nslookup of $server"; + open(T,">/tmp/expn$$") || die "open > /tmp/expn$$: $!\n"; + print T "set querytype=MX\n"; + print T "$server\n"; + close(T); + $cpref = 1.0E12; + undef $nserver; + open(NSLOOKUP,"nslookup < /tmp/expn$$ 2>&1 |") || die "open nslookup: $!"; + while(<NSLOOKUP>) { + print if ($debug > 2); + if (/mail exchanger = ([-A-Za-z_.0-9+]+)/) { + $nh = $1; + if (/preference = (\d+)/) { + $pref = $1; + if ($pref < $cpref) { + $nserver = $nh; + $cpref = $pref; + } elsif ($pref) { + $fallback{$pref} .= " $nh"; + } + } + } + if (/Non-existent domain/) { + # + # These addresses are hosed. Kaput! Dead! + # However, if we created the address in the + # first place then there is a chance of + # salvation. + # + 1 while(<NSLOOKUP>); + close(NSLOOKUP); + return 0 unless $lastchance; + &giveup('domainify',"$server: Non-existent domain",undef,1); + return 0; + } + + } + close(NSLOOKUP); + unlink("/tmp/expn$$"); + unless ($nserver) { + $0 = "$o0 - finished mxlookup"; + return 0 unless $lastchance; + &giveup('mx domainify',"$server: Could not resolve address"); + return 0; + } + + # provide fallbacks in case $nserver doesn't work out + if (defined $fallback{$cpref}) { + $mx_secondary{$server} = $fallback{$cpref}; + } + + $0 = "$av0 - gethostbyname($nserver)"; + ($name,$aliases,$type,$len,$thataddr) = gethostbyname($nserver); + + unless ($thataddr) { + $0 = $o0; + return 0 unless $lastchance; + &giveup('mx domainify',"$nserver: could not resolve address"); + return 0; + } + print "MX($server) = $nserver\n" if $debug; + print "$server -> $nserver\n" if $vw && !$debug; + $mx{&trhost($server)} = $nserver; + # redeploy the users + unless (&mxredirect($server,*users)) { + return 0 unless $lastchance; + &giveup('mx domainify',"$nserver: only one level of mx redirect allowed"); + return 0; + } + $0 = "$o0 - finished mxlookup"; + return 1; +} +# if mx expansion did not help to resolve an address +# (ie: foo@bar became @baz:foo@bar, then undo the +# expansion). +# this is only used by &final +sub mxunroll +{ + local(*host,*addr) = @_; + local($r) = 0; + print "looking for mxbacktrace{$addr *** $host}\n" + if ($debug > 1); + while (defined $mxbacktrace{"$addr *** $host"}) { + print "Unrolling MX expansion: \@$host:$addr -> " + if ($debug || $verbose); + $host = $mxbacktrace{"$addr *** $host"}; + print "\@$host:$addr\n" + if ($debug || $verbose); + $r = 1; + } + return 1 if $r; + $addr = "\@$host:$addr" + if ($host =~ /\./); + return 0; +} +# register a completed expansion. Make the final address as +# simple as possible. +sub final +{ + local($addr,$host,$name,$error) = @_; + local($he); + local($hb,$hr); + local($au,$ah); + + if ($error =~ /Non-existent domain/) { + # + # If we created the domain, then let's undo the + # damage... + # + if (defined $create_host_backtrack{"$addr *** $host"}) { + while (defined $create_host_backtrack{"$addr *** $host"}) { + print "Un&domainifying($host) = " if $debug; + $host = $create_host_backtrack{"$addr *** $host"}; + print "$host\n" if $debug; + } + $error = "$host: could not locate"; + } else { + # + # If we only want valid addresses, toss out + # bad host names. + # + if ($valid) { + print STDERR "\@$host:$addr ($name) Non-existent domain\n"; + return ""; + } + } + } + + MXUNWIND: { + $0 = "$av0 - final parsing of \@$host:$addr"; + ($he = $host) =~ s/(\W)/\\$1/g; + if ($addr !~ /@/) { + # addr does not contain any host + $addr = "$addr@$host"; + } elsif ($addr !~ /$he/i) { + # if host part really something else, use the something + # else. + if ($addr =~ m/(.*)\@([^\@]+)$/) { + ($au,$ah) = ($1,$2); + print "au = $au ah = $ah\n" if $debug; + if (defined $temporary_redirect{"$addr *** $ah"}) { + $addr = "$au\@".$temporary_redirect{"$addr *** $ah"}; + print "Rewrite! to $addr\n" if $debug; + next MXUNWIND; + } + } + # addr does not contain full host + if ($valid) { + if ($host =~ /^([^\.]+)(\..+)$/) { + # host part has a . in it - foo.bar + ($hb, $hr) = ($1, $2); + if ($addr =~ /\@([^\.\@]+)$/ && ($1 eq $hb)) { + # addr part has not . + # and matches beginning of + # host part -- tack on a + # domain name. + $addr .= $hr; + } else { + &mxunroll(*host,*addr) + && redo MXUNWIND; + } + } else { + &mxunroll(*host,*addr) + && redo MXUNWIND; + } + } else { + $addr = "${addr}[\@$host]" + if ($host =~ /\./); + } + } + } + $name = "$name " if $name; + $error = " $error" if $error; + if ($valid) { + push(@final,"$name<$addr>"); + } else { + push(@final,"$name<$addr>$error"); + } + "\t$name<$addr>$error\n"; +} + +sub alarm +{ + local($alarm_action,$alarm_redirect,$alarm_user) = @_; + alarm(3600); + $SIG{ALRM} = 'handle_alarm'; +} +# this involves one great big ugly hack. +# the "next HOST" unwinds the stack! +sub handle_alarm +{ + &giveup($alarm_redirect,"Timed out during $alarm_action",$alarm_user); + next HOST; +} + +# read the rest of the current smtp daemon's response (and toss it away) +sub read_response +{ + local($done,$watch) = @_; + local(@resp); + print $s if $watch; + while(($done eq "-") && ($s = <S>) && ($s =~ /^\d+([- ])/)) { + print $s if $watch; + $done = $1; + push(@resp,$s); + } + return @resp; +} +# print args if verbose. Return them in any case +sub verbose +{ + local(@tp) = @_; + print "@tp" if $verbose; +} +# to pass perl -w: +@tp; +$flag_a; +$flag_d; +$flag_1; +%already_domainify_fellback; +%already_mx_fellback; +&handle_alarm; +################### BEGIN PERL/TROFF TRANSITION +.00 ; + +'di +.nr nl 0-1 +.nr % 0 +.\\"'; __END__ +.\" ############## END PERL/TROFF TRANSITION +.TH EXPN 1 "March 11, 1993" +.AT 3 +.SH NAME +expn \- recursively expand mail aliases +.SH SYNOPSIS +.B expn +.RI [ -a ] +.RI [ -v ] +.RI [ -w ] +.RI [ -d ] +.RI [ -1 ] +.IR user [@ hostname ] +.RI [ user [@ hostname ]]... +.SH DESCRIPTION +.B expn +will use the SMTP +.B expn +and +.B vrfy +commands to expand mail aliases. +It will first look up the addresses you provide on the command line. +If those expand into addresses on other systems, it will +connect to the other systems and expand again. It will keep +doing this until no further expansion is possible. +.SH OPTIONS +The default output of +.B expn +can contain many lines which are not valid +email addresses. With the +.I -aa +flag, only expansions that result in legal addresses +are used. Since many mailing lists have an illegal +address or two, the single +.IR -a , +address, flag specifies that a few illegal addresses can +be mixed into the results. More +.I -a +flags vary the ratio. Read the source to track down +the formula. With the +.I -a +option, you should be able to construct a new mailing +list out of an existing one. +.LP +If you wish to limit the number of levels deep that +.B expn +will recurse as it traces addresses, use the +.I -1 +option. For each +.I -1 +another level will be traversed. So, +.I -111 +will traverse no more than three levels deep. +.LP +The normal mode of operation for +.B expn +is to do all of its work silently. +The following options make it more verbose. +It is not necessary to make it verbose to see what it is +doing because as it works, it changes its +.BR argv [0] +variable to reflect its current activity. +To see how it is expanding things, the +.IR -v , +verbose, flag will cause +.B expn +to show each address before +and after translation as it works. +The +.IR -w , +watch, flag will cause +.B expn +to show you its conversations with the mail daemons. +Finally, the +.IR -d , +debug, flag will expose many of the inner workings so that +it is possible to eliminate bugs. +.SH ENVIRONMENT +No environment variables are used. +.SH FILES +.B /tmp/expn$$ +.B temporary file used as input to +.BR nslookup . +.SH SEE ALSO +.BR aliases (5), +.BR sendmail (8), +.BR nslookup (8), +RFC 823, and RFC 1123. +.SH BUGS +Not all mail daemons will implement +.B expn +or +.BR vrfy . +It is not possible to verify addresses that are served +by such daemons. +.LP +When attempting to connect to a system to verify an address, +.B expn +only tries one IP address. Most mail daemons +will try harder. +.LP +It is assumed that you are running domain names and that +the +.BR nslookup (8) +program is available. If not, +.B expn +will not be able to verify many addresses. It will also pause +for a long time unless you change the code where it says +.I $have_nslookup = 1 +to read +.I $have_nslookup = +.IR 0 . +.LP +Lastly, +.B expn +does not handle every valid address. If you have an example, +please submit a bug report. +.SH CREDITS +In 1986 or so, Jon Broome wrote a program of the same name +that did about the same thing. It has since suffered bit rot +and Jon Broome has dropped off the face of the earth! +(Jon, if you are out there, drop me a line) +.SH AVAILABILITY +The latest version of +.B expn +is available through anonymous ftp at +.IR ftp://ftp.idiom.com/pub/muir-programs/expn . +.SH AUTHOR +.I David Muir Sharnoff\ \ \ \ <muir@idiom.com> |