Added SMTP hunt list feature.

svn path=/trunk/; revision=905

7 files changed, 82 insertions, 78 deletions

diff --git a/NEWS b/NEWS
index 31d7ec4d..dacf3f74 100644
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,8 @@ fetchmail-3.7 ()
 
 features --
 
+* You can now specify a hunt list of SMTP forwarding hosts.
+
 * Treat unexpected EOF as a protocol error.
 
 bugs --
diff --git a/driver.c b/driver.c
index a27f9d8f..3007bd61 100644
--- a/driver.c
+++ b/driver.c
@@ -341,62 +341,75 @@ char *parse_received(struct query *ctl, char *bufp)
 static FILE *smtp_open(struct query *ctl)
 /* try to open a socket to the appropriate SMTP server for this query */ 
 {
-    struct query *lead;
-
-    lead = ctl->lead_smtp; /* go to the SMTP leader for this query */
+    struct idlist	*idp;
 
     /* maybe it's time to close the socket in order to force delivery */
-    if (ctl->batchlimit && lead->smtp_sockfp && batchcount++==ctl->batchlimit)
+    if (ctl->batchlimit && ctl->smtp_sockfp && batchcount++ == ctl->batchlimit)
     {
-	fclose(lead->smtp_sockfp);
-	lead->smtp_sockfp = (FILE *)NULL;
+	fclose(ctl->smtp_sockfp);
+	ctl->smtp_sockfp = (FILE *)NULL;
 	batchcount = 0;
     }
 
-    /* 
-     * RFC 1123 requires that the domain name in HELO address is a
-     * "valid principal domain name" for the client host.  We
-     * violate this with malice aforethought in order to make the
-     * Received headers and logging look right.
-     *
-     * In fact this code relies on the RFC1123 requirement that the
-     * SMTP listener must accept messages even if verification of the
-     * HELO name fails (RFC1123 section 5.2.5, paragraph 2).
-     */
-
-    /* if no socket to this host is already set up, try to open ESMTP */
-    if (lead->smtp_sockfp == (FILE *)NULL)
+    /* run down the SMTP hunt list looking for a server that's up */
+    for (idp = ctl->smtphunt; idp; idp = idp->next)
     {
-	if ((lead->smtp_sockfp = SockOpen(lead->smtphost, SMTP_PORT)) == (FILE *)NULL)
-	    return((FILE *)NULL);
-	else if (SMTP_ok(lead->smtp_sockfp) != SM_OK
-		 || SMTP_ehlo(lead->smtp_sockfp, 
-			      ctl->server.names->id,
-			      &lead->server.esmtp_options) != SM_OK)
+
+	/* 
+	 * RFC 1123 requires that the domain name in HELO address is a
+	 * "valid principal domain name" for the client host.  We
+	 * violate this with malice aforethought in order to make the
+	 * Received headers and logging look right.
+	 *
+	 * In fact this code relies on the RFC1123 requirement that the
+	 * SMTP listener must accept messages even if verification of the
+	 * HELO name fails (RFC1123 section 5.2.5, paragraph 2).
+	 */
+
+	/* if no socket to this host is already set up, try to open ESMTP */
+	if (ctl->smtp_sockfp == (FILE *)NULL)
 	{
-	    /*
-	     * RFC 1869 warns that some listeners hang up on a failed EHLO,
-	     * so it's safest not to assume the socket will still be good.
-	     */
-	    fclose(lead->smtp_sockfp);
-	    lead->smtp_sockfp = (FILE *)NULL;
+	    if ((ctl->smtp_sockfp = SockOpen(idp->id,SMTP_PORT))==(FILE *)NULL)
+		return((FILE *)NULL);
+	    else if (SMTP_ok(ctl->smtp_sockfp) != SM_OK
+		     || SMTP_ehlo(ctl->smtp_sockfp, 
+				  ctl->server.names->id,
+				  &ctl->server.esmtp_options) != SM_OK)
+	    {
+		/*
+		 * RFC 1869 warns that some listeners hang up on a failed EHLO,
+		 * so it's safest not to assume the socket will still be good.
+		 */
+		fclose(ctl->smtp_sockfp);
+		ctl->smtp_sockfp = (FILE *)NULL;
+	    }
+	    else
+	    {
+		ctl->smtphost = idp->id;
+		break;
+	    }
 	}
-    }
 
-    /* if opening for ESMTP failed, try SMTP */
-    if (lead->smtp_sockfp == (FILE *)NULL)
-    {
-	if ((lead->smtp_sockfp = SockOpen(lead->smtphost, SMTP_PORT)) == (FILE *)NULL)
-	    return((FILE *)NULL);
-	else if (SMTP_ok(lead->smtp_sockfp) != SM_OK
-		 || SMTP_helo(lead->smtp_sockfp, ctl->server.names->id) != SM_OK)
+	/* if opening for ESMTP failed, try SMTP */
+	if (ctl->smtp_sockfp == (FILE *)NULL)
 	{
-	    fclose(lead->smtp_sockfp);
-	    lead->smtp_sockfp = (FILE *)NULL;
+	    if ((ctl->smtp_sockfp = SockOpen(idp->id,SMTP_PORT))==(FILE *)NULL)
+		return((FILE *)NULL);
+	    else if (SMTP_ok(ctl->smtp_sockfp) != SM_OK
+		     || SMTP_helo(ctl->smtp_sockfp, ctl->server.names->id) != SM_OK)
+	    {
+		fclose(ctl->smtp_sockfp);
+		ctl->smtp_sockfp = (FILE *)NULL;
+	    }
+	    else
+	    {
+		ctl->smtphost = idp->id;
+		break;
+	    }
 	}
     }
 
-    return(lead->smtp_sockfp);
+    return(ctl->smtp_sockfp);
 }
 
 static int gen_readmsg(sockfp, len, delimited, ctl, realname)
@@ -672,7 +685,7 @@ char *realname;		/* real name of host */
 	if (!ctl->mda && ((sinkfp = smtp_open(ctl)) == NULL))
 	{
 	    free_str_list(&xmit_names);
-	    error(0, 0, "SMTP connect failed");
+	    error(0, 0, "SMTP connect to %s failed", ctl->smtphost);
 	    if (return_path)
 		free(return_path);
 	    return(PS_SMTP);
diff --git a/fetchmail.c b/fetchmail.c
index a351e84e..bd31e0a0 100644
--- a/fetchmail.c
+++ b/fetchmail.c
@@ -526,7 +526,7 @@ static int load_params(int argc, char **argv, int optind)
     def_opts.server.protocol = P_AUTO;
     def_opts.server.timeout = CLIENT_TIMEOUT;
     def_opts.remotename = user;
-    def_opts.smtphost = fetchmailhost;
+    save_str(&def_opts.smtphunt, -1, fetchmailhost);
 
     /* this builds the host list */
     if (prc_parse_file(rcfile) != 0)
@@ -608,32 +608,7 @@ static int load_params(int argc, char **argv, int optind)
 	    }
 #endif /* !HAVE_GETHOSTBYNAME || !HAVE_RES_SEARCH */
 
-	    /*
-	     * Assign SMTP leaders.  We want to allow all query blocks
-	     * sharing the same server/SMTP-host pair to use the same
-	     * SMTP connection.  To accomplish this, we initialize
-	     * each query block's leader field to point to the first
-	     * block in the list with a matching server/SMTP-host pair.
-	     *
-	     * In the typical case, there will be only one SMTP host (the
-	     * client machine) and thus just one SMTP leader (and one listener
-	     * process) through the entire poll cycle.
-	     */
-	    if (!ctl->mda)
-	    {
-		ctl->smtp_sockfp = (FILE *)NULL;
-		for (mp = querylist; mp && mp != ctl; mp = mp->next)
-		    if (!strcmp(mp->server.names->id, ctl->server.names->id)
-			&& !strcmp(mp->smtphost, ctl->smtphost))
-		    {
-			ctl->lead_smtp = mp->lead_smtp;
-			goto no_new_leader;
-		    }
-		ctl->lead_smtp = ctl;
-	    no_new_leader:;
-	    }
-
-	    /* similarly, compute server leaders for queries */
+	    /* compute server leaders for queries */
 	    for (mp = querylist; mp && mp != ctl; mp = mp->next)
 		if (strcmp(mp->server.names->id, ctl->server.names->id) == 0)
 		{
@@ -713,7 +688,7 @@ void termhook(int sig)
     else
 	/* terminate all SMTP connections cleanly */
 	for (ctl = querylist; ctl; ctl = ctl->next)
-	    if (ctl->lead_smtp == ctl && ctl->smtp_sockfp != (FILE *)NULL)
+	    if (ctl->smtp_sockfp != (FILE *)NULL)
 		SMTP_quit(ctl->smtp_sockfp);
 
     if (!check_only)
@@ -877,7 +852,14 @@ void dump_params (struct query *ctl)
     if (ctl->mda)
 	printf("  Messages will be delivered with '%s.'\n", visbuf(ctl->mda));
     else
-	printf("  Messages will be SMTP-forwarded to '%s'.\n", visbuf(ctl->smtphost));
+    {
+	struct idlist *idp;
+
+	printf("  Messages will be SMTP-forwarded to:");
+	for (idp = ctl->smtphunt; idp; idp = idp->next)
+	    printf(" %s", idp->id);
+	printf("\n");
+    }
     if (ctl->preconnect)
 	printf("  Server connection will be preinitialized with '%s.'\n", visbuf(ctl->preconnect));
     else if (outlevel == O_VERBOSE)
diff --git a/fetchmail.h b/fetchmail.h
index eed7b1ea..063b2a16 100644
--- a/fetchmail.h
+++ b/fetchmail.h
@@ -102,6 +102,7 @@ struct query
     char *remotename;
     char *password;
     char *mailbox;
+    struct idlist *smtphunt;
     char *smtphost;
     char *mda;
     char *preconnect;
@@ -123,7 +124,6 @@ struct query
     int active;
     int errcount;		/* count transient errors in last pass */
     struct query *next;		/* next query control block in chain */
-    struct query *lead_smtp;	/* pointer to this query's SMTP leader */
     FILE *smtp_sockfp;		/* socket descriptor for SMTP connection */
     unsigned int uid;		/* UID of user to deliver to */
     char digest [DIGESTLEN];	/* md5 digest buffer */
diff --git a/fetchmail.man b/fetchmail.man
index fcd5c350..2546a800 100644
--- a/fetchmail.man
+++ b/fetchmail.man
@@ -166,8 +166,10 @@ under POP3 or ETRN.
 .SS Delivery Control Options
 .TP
 .B \-S host, --smtphost host
-Specify a host to forward mail to (other than localhost).
+Specify a hunt list of hosts to forward mail to.  
 In ETRN mode, set the host that the mailserver is asked to ship mail to.
+Hosts are tried in list order; the first one that is up becomes the
+forwarding or ETRN target for the current run.
 .TP
 .B \-m, \--mda
 You can force mail to be passed to an MDA directly (rather than
diff --git a/options.c b/options.c
index a723a7cd..7081ee84 100644
--- a/options.c
+++ b/options.c
@@ -247,7 +247,7 @@ struct query *ctl;	/* option record to be initialized */
 	    break;
 	case 'S':
 	case LA_SMTPHOST:
-	    ctl->smtphost = xstrdup(optarg);
+	    save_str(&ctl->smtphunt, -1, optarg);
 	    ocount++;
 	    break;
 	case 'b':
diff --git a/rcfile_y.y b/rcfile_y.y
index 029b84de..199e57aa 100644
--- a/rcfile_y.y
+++ b/rcfile_y.y
@@ -176,6 +176,10 @@ mapping		: STRING
 				{save_str_pair(&current.localnames, $1, $3);}
 		;
 
+smtphunt	: STRING		{save_str(&current.smtphunt, -1, $1);}
+		| smtphunt STRING	{save_str(&current.smtphunt, -1, $2);}
+		;
+
 user_option	: TO localnames HERE
 		| TO localnames
 		| IS localnames HERE
@@ -184,7 +188,7 @@ user_option	: TO localnames HERE
 		| IS STRING THERE	{current.remotename = xstrdup($2);}
 		| PASSWORD STRING	{current.password   = xstrdup($2);}
 		| FOLDER STRING 	{current.mailbox    = xstrdup($2);}
-		| SMTPHOST STRING	{current.smtphost   = xstrdup($2);}
+		| SMTPHOST smtphunt
 		| MDA STRING		{current.mda        = xstrdup($2);}
 		| PRECONNECT STRING	{current.preconnect = xstrdup($2);}
 
@@ -350,7 +354,8 @@ static void record_current(void)
     FLAG_FORCE(remotename);
     FLAG_FORCE(password);
     FLAG_FORCE(mailbox);
-    FLAG_FORCE(smtphost);
+    if (cmd_opts.smtphunt)
+	save_str(&current.smtphunt, -1, cmd_opts.smtphunt->id);
     FLAG_FORCE(mda);
     FLAG_FORCE(preconnect);
 
@@ -373,6 +378,7 @@ void optmerge(struct query *h2, struct query *h1)
 {
     append_str_list(&h2->server.localdomains, &h1->server.localdomains);
     append_str_list(&h2->localnames, &h1->localnames);
+    append_str_list(&h2->smtphunt, &h1->smtphunt);
 
 #define FLAG_MERGE(fld) if (!h2->fld) h2->fld = h1->fld
     FLAG_MERGE(server.protocol);
@@ -392,7 +398,6 @@ void optmerge(struct query *h2, struct query *h1)
     FLAG_MERGE(remotename);
     FLAG_MERGE(password);
     FLAG_MERGE(mailbox);
-    FLAG_MERGE(smtphost);
     FLAG_MERGE(mda);
     FLAG_MERGE(preconnect);