From a01d05ea35365933db365ad5443d44d24cd933f7 Mon Sep 17 00:00:00 2001
From: Daniel Richard G <skunk@iSKUNK.ORG>
Date: Sun, 23 Apr 2023 06:23:20 -0400
Subject: [PATCH] Implement new DELIVERY config parameter.

This allows dma to support three modes of delivery: local-only,
remote-only, and local + remote (the default). It supersedes the
NULLCLIENT directive, which is equivalent to the remote-only mode.

Fixes: #121
---
 conf.c   | 27 +++++++++++++++++++++------
 dma.8    | 22 +++++++++++++---------
 dma.c    | 11 ++++++-----
 dma.conf |  6 ++++--
 dma.h    |  3 ++-
 5 files changed, 46 insertions(+), 23 deletions(-)

diff --git a/conf.c b/conf.c
index 0c88bb1..cd40f04 100644
--- a/conf.c
+++ b/conf.c
@@ -216,9 +216,23 @@ parse_conf(const char *config_path)
                                 user = NULL;
 			config.masquerade_host = host;
 			config.masquerade_user = user;
+		} else if (strcmp(word, "DELIVERY") == 0 && data != NULL) {
+			if (strcmp(data, "LOCALANDREMOTE") == 0)
+				config.features |= (DELIVERY_LOCAL | DELIVERY_REMOTE);
+			else if (strcmp(data, "LOCALONLY") == 0) {
+				config.features |=  DELIVERY_LOCAL;
+				config.features &= ~DELIVERY_REMOTE;
+			} else if (strcmp(data, "REMOTEONLY") == 0) {
+				config.features &= ~DELIVERY_LOCAL;
+				config.features |=  DELIVERY_REMOTE;
+			} else {
+				errlogx(EX_CONFIG, "invalid DELIVERY value in %s:%d", config_path, lineno);
+				/* NOTREACHED */
+			}
+			free(data);
 		} else if (strcmp(word, "STARTTLS") == 0 && data == NULL)
 			config.features |= STARTTLS;
-		else if (strcmp(word, "FINGERPRINT") == 0) {
+		else if (strcmp(word, "FINGERPRINT") == 0 && data != NULL) {
 			if (strlen(data) != SHA256_DIGEST_LENGTH * 2) {
 				errlogx(EX_CONFIG, "invalid sha256 fingerprint length");
 			}
@@ -244,16 +258,17 @@ parse_conf(const char *config_path)
 			config.features |= INSECURE;
 		else if (strcmp(word, "FULLBOUNCE") == 0 && data == NULL)
 			config.features |= FULLBOUNCE;
-		else if (strcmp(word, "NULLCLIENT") == 0 && data == NULL)
-			config.features |= NULLCLIENT;
-		else {
+		else if (strcmp(word, "NULLCLIENT") == 0 && data == NULL) {
+			config.features &= ~DELIVERY_LOCAL;
+			config.features |=  DELIVERY_REMOTE;
+		} else {
 			errlogx(EX_CONFIG, "syntax error in %s:%d", config_path, lineno);
 			/* NOTREACHED */
 		}
 	}
 
-	if ((config.features & NULLCLIENT) && config.smarthost == NULL) {
-		errlogx(EX_CONFIG, "%s: NULLCLIENT requires SMARTHOST", config_path);
+	if (!(config.features & DELIVERY_LOCAL) && config.smarthost == NULL) {
+		errlogx(EX_CONFIG, "%s: remote-only delivery requires SMARTHOST", config_path);
 		/* NOTREACHED */
 	}
 
diff --git a/dma.8 b/dma.8
index cf8eb6a..2adf6cd 100644
--- a/dma.8
+++ b/dma.8
@@ -315,16 +315,20 @@ setting it to
 will send all mails as
 .Ql Sm off Va username @percolator .
 .Sm on
-.It Ic NULLCLIENT Xo
-(boolean, default=commented)
+.It Ic DELIVERY Xo
+(string, default=LOCALANDREMOTE)
 .Xc
-Bypass aliases and local delivery, and instead forward all mails to
-the defined
-.Sq SMARTHOST .
-.Sq NULLCLIENT
-requires
-.Sq SMARTHOST
-to be set.
+Type(s) of delivery that
+.Nm
+should perform.
+Set this to
+.Sq LOCALONLY
+to allow only deliveries to local recipients.
+Set it to
+.Sq REMOTEONLY
+to forward all messages to the defined
+.Sq SMARTHOST ,
+bypassing local aliases.
 .El
 .Ss Environment variables
 The behavior of
diff --git a/dma.c b/dma.c
index 5206691..0040a42 100644
--- a/dma.c
+++ b/dma.c
@@ -81,7 +81,7 @@ struct config config = {
 	.spooldir	= "/var/spool/dma",
 	.authpath	= NULL,
 	.certfile	= NULL,
-	.features	= 0,
+	.features	= DELIVERY_LOCAL | DELIVERY_REMOTE,
 	.mailname	= NULL,
 	.masquerade_host = NULL,
 	.masquerade_user = NULL,
@@ -233,10 +233,9 @@ add_recp(struct queue *queue, const char *str, int expand)
 	LIST_INSERT_HEAD(&queue->queue, it, next);
 
 	/**
-	 * Do local delivery if there is no @.
-	 * Do not do local delivery when NULLCLIENT is set.
+	 * Do local delivery if there is no @ and DELIVERY_LOCAL is set.
 	 */
-	if (strrchr(it->addr, '@') == NULL && (config.features & NULLCLIENT) == 0) {
+	if (strrchr(it->addr, '@') == NULL && (config.features & DELIVERY_LOCAL)) {
 		it->remote = 0;
 		if (expand) {
 			aliased = do_alias(queue, it->addr);
@@ -255,8 +254,10 @@ add_recp(struct queue *queue, const char *str, int expand)
 				endpwent();
 			}
 		}
-	} else {
+	} else if (config.features & DELIVERY_REMOTE) {
 		it->remote = 1;
+	} else {
+		return (-1);
 	}
 
 	return (0);
diff --git a/dma.conf b/dma.conf
index fa95fc1..5a9690b 100644
--- a/dma.conf
+++ b/dma.conf
@@ -66,5 +66,7 @@
 # MASQUERADE percolator  will send mails as $username@percolator, e.g. fish@percolator
 # MASQUERADE herb@ert  will send all mails as herb@ert
 
-# Directly forward the mail to the SMARTHOST bypassing aliases and local delivery
-#NULLCLIENT
+# Uncomment and set to LOCALONLY or REMOTEONLY if you want local-only or
+# remote-only delivery.  Note that remote-only mode requires SMARTHOST to
+# be specified, and ignores local aliases.
+#DELIVERY LOCALANDREMOTE
diff --git a/dma.h b/dma.h
index 9e7f6cd..05df7a8 100644
--- a/dma.h
+++ b/dma.h
@@ -69,7 +69,8 @@
 #define INSECURE	0x020		/* Allow plain login w/o encryption */
 #define FULLBOUNCE	0x040		/* Bounce the full message */
 #define TLS_OPP		0x080		/* Opportunistic STARTTLS */
-#define NULLCLIENT	0x100		/* Nullclient support */
+#define DELIVERY_LOCAL	0x100		/* Do local delivery */
+#define DELIVERY_REMOTE	0x200		/* Do remote delivery */
 
 #ifndef CONF_PATH
 #error Please define CONF_PATH