odhcpd: make ubus optional at runtime

This is mostly for developer convenience, allowing ubus to be built in, but
disabled at will when launching odhcpd.

Signed-off-by: David Härdeman <david@hardeman.nu>
Link: https://github.com/openwrt/odhcpd/pull/312
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

4 files changed, 46 insertions, 16 deletions

diff --git a/src/config.c b/src/config.c
index a84021e..84e2f73 100644
--- a/src/config.c
+++ b/src/config.c
@@ -37,6 +37,11 @@ struct config config = {
 	.enable_tz = true,
 	.main_dhcpv4 = false,
 	.dhcp_cb = NULL,
+#ifdef WITH_UBUS
+	.use_ubus = true,
+#else
+	.use_ubus = false,
+#endif /* WITH_UBUS */
 	.dhcp_statefile = NULL,
 	.dhcp_statedir_fd = -1,
 	.dhcp_hostsdir = NULL,
@@ -1119,10 +1124,9 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
 			ifname = blobmsg_get_string(c);
 	}
 
-#ifdef WITH_UBUS
 	if (overwrite || !iface->ifname)
-		ifname = ubus_get_ifname(name);
-#endif
+		if (config.use_ubus)
+			ifname = ubus_get_ifname(name);
 
 	if (!iface->ifname && !ifname)
 		goto err;
@@ -2381,10 +2385,9 @@ void odhcpd_reload(void)
 			continue;
 
 		enum odhcpd_mode hybrid_mode = MODE_DISABLED;
-#ifdef WITH_UBUS
-		if (!ubus_has_prefix(i->name, i->ifname))
+
+		if (config.use_ubus && !ubus_has_prefix(i->name, i->ifname))
 			hybrid_mode = MODE_RELAY;
-#endif
 
 		if (i->dhcpv6 == MODE_HYBRID)
 			i->dhcpv6 = hybrid_mode;
@@ -2441,10 +2444,12 @@ int odhcpd_run(void)
 {
 	static struct uloop_signal sighup = { .signo = SIGHUP, .cb = signal_reload };
 
-	while (ubus_init()) {
-		if (uloop_cancelled)
-			return EXIT_FAILURE;
-		sleep(1);
+	if (config.use_ubus) {
+		while (ubus_init()) {
+			if (uloop_cancelled)
+				return EXIT_FAILURE;
+			sleep(1);
+		}
 	}
 
 	odhcpd_reload();
diff --git a/src/odhcpd.c b/src/odhcpd.c
index bc0a833..f67e419 100644
--- a/src/odhcpd.c
+++ b/src/odhcpd.c
@@ -67,7 +67,7 @@ void __iflog(int lvl, const char *fmt, ...)
 	va_end(ap);
 }
 
-static void print_usage(const char *app)
+_o_noreturn static void print_usage(const char *app, int exit_status)
 {
 	printf("== %s Usage ==\n"
 	       "Features: ra ndp dhcpv6"
@@ -86,8 +86,13 @@ static void print_usage(const char *app)
 	       "	-c <dir>	Read UCI configuration files from <dir>\n"
 	       "	-l <int>	Specify log level 0..7 (default %d)\n"
 	       "	-f		Log to stderr instead of syslog\n"
+#ifdef WITH_UBUS
+	       "	-u		Disable ubus support\n"
+#endif /* WITH_UBUS */
 	       "	-h		Print this help text and exit\n",
 	       app, config.log_level);
+
+	exit(exit_status);
 }
 
 static bool ipv6_enabled(void)
@@ -106,7 +111,7 @@ int main(int argc, char **argv)
 {
 	int opt;
 
-	while ((opt = getopt(argc, argv, "c:l:fh")) != -1) {
+	while ((opt = getopt(argc, argv, "c:l:fuh")) != -1) {
 		switch (opt) {
 		case 'c':
 			struct stat sb;
@@ -135,9 +140,15 @@ int main(int argc, char **argv)
 			config.log_syslog = false;
 			fprintf(stderr, "Logging to stderr\n");
 			break;
+		case 'u':
+			config.use_ubus = false;
+			fprintf(stderr, "Ubus support disabled\n");
+			break;
 		case 'h':
-			print_usage(argv[0]);
-			return 0;
+			print_usage(argv[0], EXIT_SUCCESS);
+		case '?':
+		default:
+			print_usage(argv[0], EXIT_FAILURE);
 		}
 	}
 
diff --git a/src/odhcpd.h b/src/odhcpd.h
index f41aaa1..06cc332 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -65,6 +65,10 @@
 #define _o_unused __attribute__((unused))
 #endif /* _o_unused */
 
+#ifndef _o_noreturn
+#define _o_noreturn __attribute__((__noreturn__))
+#endif /* _o_noreturn */
+
 #define ALL_IPV6_NODES "ff02::1"
 #define ALL_IPV6_ROUTERS "ff02::2"
 
@@ -202,10 +206,10 @@ enum duid_type {
 };
 
 struct config {
-	bool legacy;
 	bool enable_tz;
 	bool main_dhcpv4;
 	char *dhcp_cb;
+	bool use_ubus;
 
 	char *dhcp_statefile;
 	int dhcp_statedir_fd;
@@ -580,11 +584,21 @@ static inline int ubus_init(void)
 	return 0;
 }
 
+static inline const char *ubus_get_ifname(const char *name)
+{
+	return NULL;
+}
+
 static inline void ubus_apply_network(void)
 {
 	return;
 }
 
+static inline bool ubus_has_prefix(const char *name, const char *ifname)
+{
+	return false;
+}
+
 static inline
 void ubus_bcast_dhcpv4_event(const char *type, const char *iface,
 			     const struct dhcpv4_lease *lease)
diff --git a/src/ubus.c b/src/ubus.c
index 9e51622..426c1a2 100644
--- a/src/ubus.c
+++ b/src/ubus.c
@@ -473,7 +473,7 @@ bool ubus_has_prefix(const char *name, const char *ifname)
 	unsigned rem;
 
 	if (!dump)
-		return NULL;
+		return false;
 
 	blobmsg_for_each_attr(c, dump, rem) {
 		struct blob_attr *tb[IFACE_ATTR_MAX];