From 3c2b96ae3364a3bc206679f49a858f8fee505ba4 Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Fri, 25 Oct 1996 06:22:14 +0000
Subject: Another pass at making multidrop work OK.

svn path=/trunk/; revision=376
---
 INSTALL       |  3 +++
 driver.c      | 46 ++++++++++++++++++++++++----------------------
 fetchmail.man | 10 +++++++---
 3 files changed, 34 insertions(+), 25 deletions(-)

diff --git a/INSTALL b/INSTALL
index e6beffb6..4c191f1a 100644
--- a/INSTALL
+++ b/INSTALL
@@ -74,6 +74,9 @@ distributed with Pine from the University of Washington.  Other
 POP3 servers have been known to give it indigestion.  Test carefully!
 If you have problems, switch to imap.
 
+If you're going to use multi-drop mailboxes, test with particular care.
+This code was very difficult to test and should be considered experimental.
+
 6. USE IT
 
 Enjoy!
diff --git a/driver.c b/driver.c
index 462b31e4..5b4fc702 100644
--- a/driver.c
+++ b/driver.c
@@ -349,32 +349,34 @@ struct idlist **xmit_names;	/* list of recipient names parsed out */
 	return;
     else
     {
-	char	*cp = nxtaddr(hdr), *lname;
+	char	*cp, *lname;
 
-	do {
-	    char	*atsign = strchr(cp, '@');
+	if ((cp = nxtaddr(hdr)) != (char *)NULL)
+	    do {
+		char	*atsign = strchr(cp, '@');
 
-	    if (atsign)
-		if (queryctl->norewrite)
-		    continue;
-	        else
-	        {
-		    if (!is_host_alias(atsign+1, 
-				       queryctl->servername,
-				       queryctl->canonical_name))
+		if (atsign)
+		    if (queryctl->norewrite)
 			continue;
-		    atsign[0] = '\0';
+		    else
+		    {
+			if (!is_host_alias(atsign+1, 
+					   queryctl->servername,
+					   queryctl->canonical_name))
+			    continue;
+			atsign[0] = '\0';
+		    }
+		lname = idpair_find(&queryctl->localnames, cp);
+		if (lname != (char *)NULL)
+		{
+		    if (outlevel == O_VERBOSE)
+			fprintf(stderr,
+				"fetchmail: mapped %s to local %s\n",
+				cp, lname);
+		    save_uid(xmit_names, -1, lname);
 		}
-	    if ((lname = idpair_find(&queryctl->localnames, cp))!=(char *)NULL)
-	    {
-		if (outlevel == O_VERBOSE)
-		    fprintf(stderr,
-			    "fetchmail: mapped %s to local %s\n",
-			    cp, lname);
-		save_uid(xmit_names, -1, lname);
-	    }
-	} while
-	    ((cp = nxtaddr((char *)NULL)) != (char *)NULL);
+	    } while
+		((cp = nxtaddr((char *)NULL)) != (char *)NULL);
     }
 }
 #endif /* HAVE_GETHOSTBYNAME */
diff --git a/fetchmail.man b/fetchmail.man
index 5cab1cf5..0cfb5af0 100644
--- a/fetchmail.man
+++ b/fetchmail.man
@@ -683,14 +683,18 @@ to the mailserver.  This creates a risk that name/password pairs
 might be snaffled with a packet sniffer or more sophisticated
 monitoring software.
 .PP
-Retrieval and forwarding from multi-drop server mailboxes is only as
-reliable as your mail server host's DNS service.  Each host
+Retrieval and forwarding from multi-drop server mailboxes is at most
+as reliable as your mail server host's DNS service.  Each host
 address part in each message of a multi-drop mailbox is checked 
 with
 .BR gethostbyname (2)
 to see if it's an alias of the mail server.  If it is, but the
 lookup fails due to network congestion or a crashed server, forwarding
-will not get done correctly. 
+will not get done correctly.  Note: this check will \fInot\fR catch
+equivalences created by MX records!
+.PP
+The multi-drop mailbox code was hard to test thoroughly and may have obscure
+failure modes, especially in the presence of DNS flakiness.
 .PP
 Under Linux, if fetchmail is run in daemon mode with the network
 inaccessible, each poll leaves a socket allocated but in CLOSE state
-- 
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