diff options
Diffstat (limited to 'pullimap')
| -rwxr-xr-x | pullimap | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/pullimap b/pullimap new file mode 100755 index 0000000..27226d2 --- /dev/null +++ b/pullimap @@ -0,0 +1,331 @@ +#!/usr/bin/perl -T + +#---------------------------------------------------------------------- +# Pull mails from an IMAP mailbox and deliver them to a SMTP session +# Copyright © 2016 Guilhem Moulin <guilhem@fripost.org> +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. +#---------------------------------------------------------------------- + +use strict; +use warnings; + +our $VERSION = '0.3'; +my $NAME = 'pullimap'; + +use Errno 'EINTR'; +use Fcntl qw/O_CREAT O_RDWR O_DSYNC LOCK_EX SEEK_SET F_GETFL F_SETFL FD_CLOEXEC/; +use Getopt::Long qw/:config posix_default no_ignore_case gnu_getopt auto_version/; +use List::Util 'first'; +use Socket qw/PF_INET PF_INET6 SOCK_STREAM/; + +use lib 'lib'; +use Net::IMAP::InterIMAP qw/read_config compact_set/; + +my %CONFIG; +sub usage(;$) { + my $rv = shift // 0; + if ($rv) { + print STDERR "Usage: $NAME [OPTIONS] SECTION\n" + ."Try '$NAME --help' or consult the manpage for more information.\n"; + } + else { + print STDERR "Usage: $NAME [OPTIONS] SECTION\n" + ."Consult the manpage for more information.\n"; + } + exit $rv; +} + +usage(1) unless GetOptions(\%CONFIG, qw/config=s quiet|q debug help|h idle:i no-delivery/); +usage(0) if $CONFIG{help}; +usage(1) unless $#ARGV == 0 and $ARGV[0] ne '_'; + + +####################################################################### +# Read and validate configuration +# +my $CONF = read_config( delete $CONFIG{config} // $NAME, + , [$ARGV[0]] + , statefile => qr/\A(\P{Control}+)\z/ + , mailbox => qr/\A([\x01-\x7F]+)\z/ + , 'deliver-method' => qr/\A([ls]mtp:\[.*\]:\d+)\z/ + , 'deliver-ehlo' => qr/\A(\P{Control}+)\z/ + , 'deliver-rcpt' => qr/\A(\P{Control}+)\z/ + , 'purge-after' => qr/\A(\d+)\z/ + )->{$ARGV[0]}; + +my ($MAILBOX, $STATE); +do { + $MAILBOX = $CONF->{mailbox} // 'INBOX'; + + my $statefile = $CONF->{statefile} // $ARGV[0]; + die "Missing option statefile" unless defined $statefile; + $statefile = $statefile =~ /\A(\p{Print}+)\z/ ? $1 : die "Insecure $statefile"; + + unless ($statefile =~ /\A\//) { + my $dir = ($ENV{XDG_DATA_HOME} // "$ENV{HOME}/.local/share") .'/'. $NAME; + $dir = $dir =~ /\A(\/\p{Print}+)\z/ ? $1 : die "Insecure $dir"; + $statefile = $dir .'/'. $statefile; + unless (-d $dir) { + mkdir $dir, 0700 or die "Can't mkdir $dir: $!\n"; + } + } + + sysopen($STATE, $statefile, O_CREAT|O_RDWR|O_DSYNC, 0600) or die "Can't open $statefile: $!"; + my $flags = fcntl($STATE, F_GETFL, 0) or die "fcntl F_GETFL: $!"; + fcntl($STATE, F_SETFL, $flags | FD_CLOEXEC) or die "fcntl F_SETFL: $!"; + + flock($STATE, LOCK_EX) or die "Can't flock $statefile: $!"; +}; + + +####################################################################### + +# Read a UID (32-bits integer) from the statefile, or undef if we're at +# the end of the statefile +sub readUID() { + my $n = sysread($STATE, my $buf, 4) // die "Can't sysread: $!"; + return if $n == 0; # EOF + # file length is a multiple of 4 bytes, and we always read 4 bytes at a time + die "Corrupted state file!" if $n != 4; + unpack('N', $buf); +} + +# Write a UID (32-bits integer) to the statefile +sub writeUID($) { + my $uid = pack('N', shift); + my $offset = 0; + for ( my $offset = 0 + ; $offset < 4 + ; $offset += syswrite($STATE, $uid, 4-$offset, $offset) // die "Can't syswrite: $!" + ) {} +} + + +####################################################################### +# SMTP/LMTP part +# +my ($SMTP, $SMTP_PIPELINING); +sub sendmail($$) { + my ($from, $rfc822) = @_; + unless (defined $SMTP) { + # TODO we need to be able to reconnect when the server closes + # the connection due to a timeout (RFC 5321 section 4.5.3.2) + my ($fam, $addr) = (PF_INET, $CONF->{'deliver-method'} // 'smtp:[127.0.0.1]:25'); + $addr =~ s/^([ls]mtp):// or die; + my $ehlo = $1 eq 'lmtp' ? 'LHO' : $1 eq 'smtp' ? 'EHLO' : die; + $ehlo .= ' '. ($CONF->{'deliver-ehlo'} // 'localhost.localdomain'); + + my $port = $addr =~ s/:(\d+)$// ? $1 : die; + $addr =~ s/^\[(.*)\]$/$1/ or die; + $fam = PF_INET6 if $addr =~ /:/; + $addr = Socket::inet_pton($fam, $addr) // die "Invalid address $addr\n"; + my $sockaddr = $fam == PF_INET ? Socket::pack_sockaddr_in($port, $addr) + : $fam == PF_INET6 ? Socket::pack_sockaddr_in6($port, $addr) + : die; + + my $proto = getprotobyname("tcp") // die; + socket($SMTP, $fam, SOCK_STREAM, $proto) or die "socket: $!"; + until (connect($SMTP, $sockaddr)) { + next if $! == EINTR; # try again if connect(2) was interrupted by a signal + die "connect: $!"; + } + + smtp_resp('220'); + my @r = smtp_send($ehlo => '250'); + $SMTP_PIPELINING = grep {$_ eq 'PIPELINING'} @r; # SMTP pipelining (RFC 2920) + } + my $rcpt = $CONF->{'deliver-rcpt'} // getpwuid($>) // die; + + # return codes are from RFC 5321 section 4.3.2 + smtp_send( "MAIL FROM:<$from>" => '250' + , "RCPT TO:<$rcpt>" => '250' + , "DATA" => '354' + ); + + print STDERR "C: [...]\n" if $CONFIG{debug}; + if ($$rfc822 eq '') { + # RFC 5321 section 4.1.1.4: if there was no mail data, the first + # "\r\n" ends the DATA command itself + $SMTP->printflush("\r\n.\r\n"); + } else { + my $offset = 0; + my $length = length($$rfc822); + while ((my $end = index($$rfc822, "\r\n", $offset) + 2) != 1) { + my $line = substr($$rfc822, $offset, $end-$offset); + # RFC 5321 section 4.5.2: the character sequence "\r\n.\r\n" + # ends the mail text and cannot be sent by the user + $SMTP->print($line eq ".\r\n" ? "..\r\n" : $line); + $offset = $end; + } + if ($offset < $length) { + # the last line did not end with "\r\n"; add it in order to + # have the receiving SMTP server recognize the "end of data" + # condition. See RFC 5321 section 4.1.1.4 + my $line = substr($$rfc822, $offset); + $SMTP->print(($line eq "." ? ".." : $line), "\r\n"); + } + $SMTP->printflush(".\r\n"); + } + smtp_resp('250'); +} +sub smtp_resp($) { + my $code = shift; + my @resp; + while(1) { + local $_ = $SMTP->getline() // die; + s/\r\n\z// or die "Invalid SMTP reply: $_"; + print STDERR "S: $_\n" if $CONFIG{debug}; + s/\A\Q$code\E([ -])// or die "SMTP error: Expected $code, got: $_\n"; + push @resp, $_; + return @resp if $1 eq ' '; + } +} +sub smtp_send(@) { + my (@cmd, @code, @r); + while (@_) { + push @cmd, shift // die; + push @code, shift // die; + } + if ($SMTP_PIPELINING) { # SMTP pipelining (RFC 2920) + print STDERR join('', map {"C: $_\n"} @cmd) if $CONFIG{debug}; + $SMTP->printflush(join('', map {"$_\r\n"} @cmd)); + @r = smtp_resp($_) foreach @code; + } + else { + foreach (@cmd) { + print STDERR "C: $_\n" if $CONFIG{debug}; + $SMTP->printflush("$_\r\n"); + @r = smtp_resp(shift(@code)); + } + } + return @r; +} + + +####################################################################### +# Initialize the cache from the statefile, then pull new messages from +# the remote mailbox +# +$CONF->{'logger-fd'} = \*STDERR if $CONFIG{debug}; +my $IMAP = Net::IMAP::InterIMAP::->new( %$CONF, %CONFIG{qw/quiet debug/} ); + +# Remove messages with UID < UIDNEXT and INTERNALDATE at most +# $CONF->{'purge-after'} days ago. +my $LAST_PURGED; +sub purge() { + my $days = $CONF->{'purge-after'} // return; + my ($uidnext) = $IMAP->get_cache('UIDNEXT'); + return unless 1<$uidnext; + my $set = "1:".($uidnext-1); + + my $now = time; + return if defined $LAST_PURGED and $now - $LAST_PURGED < 6*3600; + $LAST_PURGED = $now; + + unless ($days == 0) { + my @now = gmtime($now - $days*86400); + my @m = qw/Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec/; # RFC 3501's date-month + my $date = sprintf("%02d-%s-%04d", $now[3], $m[$now[4]], $now[5]+1900); + my @uid = $IMAP->search("UID $set BEFORE $date"); + return unless @uid; + + $set = compact_set(@uid); + $IMAP->log("Removing ".($#uid+1)." UID(s) $set") unless $CONFIG{quiet}; + } + $IMAP->silent_store($set, '+', '\Deleted'); + $IMAP->expunge($set); +} + +# Use BODY.PEEK[] so if something gets wrong, unpulled messages +# won't be marked as \Seen in the mailbox +my $ATTRS = "ENVELOPE INTERNALDATE BODY.PEEK[]"; + +# Pull new messages from IMAP and deliver them to SMTP, then update the +# statefile +sub pull(;$) { + my $ignore = shift // []; + my @uid; + + # invariant: we're at pos 8 + 4*(1+$#ignore + 1+$#uids) in the statefile + $IMAP->pull_new_messages($ATTRS, sub($) { + my $mail = shift; + return unless exists $mail->{RFC822}; # not for us + + my $uid = $mail->{UID}; + my $from = first { defined $_ and @$_ } @{$mail->{ENVELOPE}}[2,3,4]; + $from = (defined $from and @$from) ? $from->[0]->[2].'@'.$from->[0]->[3] : ''; + print STDERR "($MAILBOX): UID $uid from <$from> ($mail->{INTERNALDATE})\n" unless $CONFIG{quiet}; + + sendmail($from, $mail->{RFC822}) unless $CONFIG{'no-delivery'}; + + push @uid, $uid; + writeUID($uid); + }, @$ignore); + + # terminate the SMTP transmission channel gracefully, cf RFC 5321 section 4.5.3.2 + smtp_send('QUIT' => '221') if defined $SMTP; + undef $SMTP; + + # now that everything has been deliverd, mark @ignore and @uid as \Seen + $IMAP->silent_store(compact_set(@$ignore, @uid), '+', '\Seen') if @$ignore or @uid; + + # update the statefile + sysseek($STATE, 4, SEEK_SET) // die "Can't seek: $!"; + my ($uidnext) = $IMAP->get_cache('UIDNEXT'); + writeUID($uidnext); + truncate($STATE, 8) // die "Can't truncate"; +} + +do { + my $uidvalidity = readUID(); + my $uidnext = readUID(); + my $ignore = []; + + $IMAP->set_cache($MAILBOX, UIDVALIDITY => $uidvalidity, UIDNEXT => $uidnext); + $IMAP->select($MAILBOX); + + unless (defined $uidvalidity) { + ($uidvalidity) = $IMAP->get_cache('UIDVALIDITY'); + # we were at pos 0 before the write, at pos 4 afterwards + writeUID($uidvalidity); + die if defined $uidnext; # sanity check + } + + if (!defined $uidnext) { + # we were at pos 4 before the write, at pos 8 afterwards + writeUID(1); + } + else { + # put the remaining UIDs in the @ignore list: these messages + # have already been delivered, but the process exited before the + # statefile was updated + while (defined (my $uid = readUID())) { + push @$ignore, $uid; + } + } + pull($ignore); + purge(); +}; +unless (defined $CONFIG{idle}) { + $IMAP->logout(); + exit 0; +} + +$CONFIG{idle} = 1740 if defined $CONFIG{idle} and $CONFIG{idle} == 0; # 29 mins +while(1) { + my $r = $IMAP->idle($CONFIG{idle}, sub() { $IMAP->has_new_mails($MAILBOX) }); + pull() if $r; + purge(); +} |