From e1298bd1f676342a78014fb27823f3944f96f9f7 Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Fri, 21 Feb 1997 04:32:42 +0000
Subject: Localize the effect of DNS errors.

svn path=/trunk/; revision=908
---
 NEWS          |  3 +++
 driver.c      | 24 +++++++++++++++---------
 fetchmail.man | 13 +++++++------
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/NEWS b/NEWS
index ce3cab03..3e63c249 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,9 @@ features --
 
 * Treat unexpected EOF as a protocol error.
 
+* DNS errors no longer abort an entire poll.  Instead they just cause 
+  forwarding and deletion of the current message.  
+
 * -v output now includes the version/pl numbers (help for harried maintainer!).
 
 bugs --
diff --git a/driver.c b/driver.c
index 24f7125a..3628e266 100644
--- a/driver.c
+++ b/driver.c
@@ -146,7 +146,6 @@ static int is_host_alias(const char *name, struct query *ctl)
 		"nameserver failure while looking for `%s' during poll of %s.",
 		name, ctl->server.names->id);
 	    ctl->errcount++;
-	    longjmp(restart, 2);	/* try again next poll cycle */
 	    break;
 	}
 
@@ -172,7 +171,6 @@ static int is_host_alias(const char *name, struct query *ctl)
 		"nameserver failure while looking for `%s' during poll of %s.",
 		name, ctl->server.names->id);
 	    ctl->errcount++;
-	    longjmp(restart, 2);	/* try again next poll cycle */
 	    break;
 	}
     }
@@ -435,10 +433,12 @@ char *realname;		/* real name of host */
 #ifdef HAVE_RES_SEARCH
     int			no_local_matches = FALSE;
 #endif /* HAVE_RES_SEARCH */
+    int			olderrs;
 
     sizeticker = 0;
     delete_ok = TRUE;
     remaining = len;
+    olderrs = ctl->errcount;
 
     /* read message headers */
     headers = received_for = return_path = NULL;
@@ -627,8 +627,18 @@ char *realname;		/* real name of host */
 #endif /* HAVE_RES_SEARCH */
 	save_str(&xmit_names, -1, ctl->localnames->id);
 
-    /* time to address the message */
-    if (ctl->mda)	/* we have a declared MDA */
+
+    /*
+     * Time to either address the message or decide we can't deliver it yet.
+     */
+    if (ctl->errcount > olderrs)	/* there were DNS errors above */
+    {
+	delete_ok = FALSE;
+	sinkfp = (FILE *)NULL;
+	if (outlevel == O_VERBOSE)
+	    error(0,0, "forwarding and deletion suppressed due to DNS errors");
+    }
+    else if (ctl->mda)		/* we have a declared MDA */
     {
 	int	length = 0;
 	char	*names, *cmd;
@@ -1045,6 +1055,7 @@ char *realname;		/* real name of host */
 	if (SMTP_eom(sinkfp) != SM_OK)
 	{
 	    error(0, 0, "SMTP listener refused delivery");
+	    ctl->errcount++;
 	    return(PS_TRANSIENT);
 	}
     }
@@ -1146,11 +1157,6 @@ const struct method *proto;	/* protocol method table */
 		ctl->server.timeout, ctl->server.names->id);
 	ok = PS_ERROR;
     }
-    else if (js == 2)
-    {
-	/* error message printed at point of longjmp */
-	ok = PS_ERROR;
-    }
     else
     {
 	char buf [POPBUFSIZE+1];
diff --git a/fetchmail.man b/fetchmail.man
index 2546a800..ebc68127 100644
--- a/fetchmail.man
+++ b/fetchmail.man
@@ -464,13 +464,14 @@ The
 or --nodetach option suppresses detachment of the daemon process
 from its control terminal.  This is primarily useful for debugging.
 .PP
-Note that while running in daemon mode, transient errors (such as DNS
-failures or sendmail delivery refusals) may force the fetchall
-option on for the duration of the next polling cycle.
+Note that while running in daemon mode polling a POP server, transient
+errors (such as DNS failures or sendmail delivery refusals) may force
+the fetchall option on for the duration of the next polling cycle.
 This is a robustness feature.  It means that if a message is fetched
-(and thus marked seen by the mailserver) but not delivered locally
-due to some transient error, it will be re-fetched during the next
-poll cycle.
+(and thus marked seen by the mailserver) but not delivered locally due
+to some transient error, it will be re-fetched during the next poll
+cycle.  (The IMAP logic doesn't delete messages until they're
+delivered, so this problem does not arise.)
 
 .SH RETRIEVAL FAILURE MODES
 The protocols \fIfetchmail\fR uses to talk to mailservers are next to
-- 
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