From 59b826d4bbdb1bc7e1d895dfefdceb612425531c Mon Sep 17 00:00:00 2001
From: Matt Sergeant <matt@sergeant.org>
Date: Fri, 26 Sep 2008 17:40:04 +0000
Subject: [PATCH] Fix to check client is writable before writing to it.

git-svn-id: https://svn.perl.org/qpsmtpd/trunk@946 958fd67b-6ff1-0310-b445-bb7760255be9
---
 lib/Qpsmtpd/TcpServer.pm         | 23 +++++++++++++++++++----
 lib/Qpsmtpd/TcpServer/Prefork.pm |  6 ++++++
 qpsmtpd-forkserver               |  2 +-
 qpsmtpd-prefork                  |  2 +-
 4 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/lib/Qpsmtpd/TcpServer.pm b/lib/Qpsmtpd/TcpServer.pm
index abf29d2..2a67902 100644
--- a/lib/Qpsmtpd/TcpServer.pm
+++ b/lib/Qpsmtpd/TcpServer.pm
@@ -67,16 +67,17 @@ sub start_connection {
 }
 
 sub run {
-    my $self = shift;
+    my ($self, $client) = @_;
 
-    # should be somewhere in Qpsmtpd.pm and not here...
-    $self->load_plugins unless $self->{hooks};
+    # Set local client_socket to passed client object for testing socket state on writes
+    $self->{__client_socket} = $client;
+
+    $self->load_plugins;
 
     my $rc = $self->start_conversation;
     return if $rc != DONE;
 
     # this should really be the loop and read_input should just get one line; I think
-
     $self->read_input;
 }
 
@@ -104,6 +105,12 @@ sub read_input {
 sub respond {
   my ($self, $code, @messages) = @_;
   my $buf = '';
+
+  if ( !$self->check_socket() ) {
+    $self->log(LOGERROR, "Lost connection to client, cannot send response.");
+    return(0);
+  }
+
   while (my $msg = shift @messages) {
     my $line = $code . (@messages?"-":" ").$msg;
     $self->log(LOGINFO, $line);
@@ -161,4 +168,12 @@ sub tcpenv {
   return ($TCPLOCALIP, $TCPREMOTEIP, $TCPREMOTEHOST || "Unknown");
 }
 
+sub check_socket() {
+  my $self = shift;
+
+  return 1 if ( $self->{__client_socket}->connected );
+ 
+  return 0;
+}
+
 1;
diff --git a/lib/Qpsmtpd/TcpServer/Prefork.pm b/lib/Qpsmtpd/TcpServer/Prefork.pm
index 96d1753..28f60dc 100644
--- a/lib/Qpsmtpd/TcpServer/Prefork.pm
+++ b/lib/Qpsmtpd/TcpServer/Prefork.pm
@@ -48,6 +48,12 @@ sub read_input {
 
 sub respond {
   my ($self, $code, @messages) = @_;
+
+  if ( !$self->check_socket() ) {
+    $self->log(LOGERROR, "Lost connection to client, cannot send response.");
+    return(0);
+  }
+
   while (my $msg = shift @messages) {
     my $line = $code . (@messages?"-":" ").$msg;
     $self->log(LOGINFO, $line);
diff --git a/qpsmtpd-forkserver b/qpsmtpd-forkserver
index 40de277..c22ff5c 100755
--- a/qpsmtpd-forkserver
+++ b/qpsmtpd-forkserver
@@ -316,7 +316,7 @@ while (1) {
        remote_ip   => $ENV{TCPREMOTEIP},
        remote_port => $port,
       );
-    $qpsmtpd->run();
+    $qpsmtpd->run($client);
     
     $qpsmtpd->run_hooks("post-connection");
     $qpsmtpd->connection->reset;
diff --git a/qpsmtpd-prefork b/qpsmtpd-prefork
index 360b414..600133c 100755
--- a/qpsmtpd-prefork
+++ b/qpsmtpd-prefork
@@ -691,7 +691,7 @@ sub qpsmtpd_session {
                                    remote_ip   => $ENV{TCPREMOTEIP},
                                    remote_port => $client->peerport,
                                   );
-        $qpsmtpd->run();
+        $qpsmtpd->run($client);
         $qpsmtpd->run_hooks("post-connection");
         $qpsmtpd->connection->reset;
     };