From ddb6ad5e4757c872d8153072fed52de54561c6a6 Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Fri, 8 Nov 1996 22:11:54 +0000
Subject: We no longer attempt delivery to multidrop mailboxes in the presence
 of DNS errors.

svn path=/trunk/; revision=519
---
 driver.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

(limited to 'driver.c')

diff --git a/driver.c b/driver.c
index 325383ce..11cde20a 100644
--- a/driver.c
+++ b/driver.c
@@ -120,12 +120,16 @@ static int is_host_alias(const char *name, struct query *ctl)
 	return(TRUE);
 
     /*
-     * We treat DNS lookup failure as a negative on the theory that
-     * the mailserver's DNS server is `nearby' and should be able
-     * to respond quickly and reliably.  Ergo if we get failure,
-     * the name isn't a mailserver alias.
+     * We know DNS service was up at the beginning of this poll cycle.
+     * If it's down, our nameserver has crashed.  We don't want to try
+     * delivering the current message or anything else from this
+     * mailbox until it's back up.
      */
-    else if ((he = gethostbyname(name)) && strcmp(ctl->canonical_name, he->h_name) == 0)
+    else if ((he = gethostbyname(name)) == (struct hostent *)NULL)
+	longjmp(restart, 2);
+
+    /* DNS response is OK */
+    else if (strcmp(ctl->canonical_name, he->h_name) == 0)
 	return(TRUE);
 
     /*
@@ -138,12 +142,15 @@ static int is_host_alias(const char *name, struct query *ctl)
 
 	mxrecords = getmxrecords(name);
 
+	h_errno = 0;
 	if (mxrecords == (struct mxentry *)NULL)
 	    if (h_errno == TRY_AGAIN)
 	    {
 		sleep(1);
 		continue;
 	    }
+	    else if (h_errno)		/* fatal error */
+		longjmp(restart, 2);
 	    else
 		break;
 
@@ -628,7 +635,7 @@ int do_protocol(ctl, proto)
 struct query *ctl;		/* parsed options with merged-in defaults */
 const struct method *proto;	/* protocol method table */
 {
-    int ok;
+    int ok, js;
     void (*sigsave)();
 
 #ifndef KERBEROS_V4
@@ -673,13 +680,20 @@ const struct method *proto;	/* protocol method table */
     sigsave = signal(SIGVTALRM, vtalarm_handler);
     vtalarm(mytimeout = ctl->timeout);
 
-    if (setjmp(restart) == 1)
+    if ((js = setjmp(restart)) == 1)
     {
 	fprintf(stderr,
 		"fetchmail: timeout after %d seconds waiting for %s.\n",
 		ctl->timeout, ctl->servername);
 	ok = PS_ERROR;
     }
+    else if (js == 2)
+    {
+	fprintf(stderr,
+		"fetchmail: nameserver evaporated during poll of %s.\n",
+		ctl->servername);
+	ok = PS_ERROR;
+    }
     else
     {
 	char buf [POPBUFSIZE+1];
-- 
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