From 00804e9fc149e1c389a0054a397aa4e5189371e3 Mon Sep 17 00:00:00 2001
From: Andrew Bettison <andrew@servalproject.org>
Date: Fri, 1 Jun 2018 11:07:00 +0930
Subject: [PATCH] Make servald_features() available to iOS app

Add servald_features.o to the libservaldaemon.a static library (was only
in libservaldaemon.so before), and create the "servald_features.h"
public header so that an iOS app's Swift code can simply refer to the
servald_features() function in order to link in all the Serval DNA
daemon features.
---
 Makefile.in        | 27 +++++++++++++++++++++------
 headerfiles.mk     |  1 +
 servald_features.c |  1 +
 servald_features.h | 20 ++++++++++++++++++++
 4 files changed, 43 insertions(+), 6 deletions(-)
 create mode 100644 servald_features.h

diff --git a/Makefile.in b/Makefile.in
index 1d43e10e..dda7639d 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -354,21 +354,36 @@ $(SIMULATOR_OBJS):			Makefile $(CONFIG_H) $(PREFIXED_HEADERS) $(LIBSODIUM_HEADER
 
 # Rules for main targets.
 
+# The daemon static library.  This is linked into any statically-linked daemon,
+# such as the Swift Daemon API module's static library, and contains all the
+# features of the full Serval DNA daemon.  It includes servald_features.o so
+# that a statically-linked server can simply reference servald_features() in
+# order to force all the features to be linked in.  It also includes all the
+libservaldaemon.a: _servald.a $(LIBSODIUM_A)
+	@$(call MERGE_STATIC_LIBS, $@, $^)
+
+# This intermediate library exists only so that libservaldaemon.a can be
+# constructed by merging two static libraries.
 .INTERMEDIATE: _servald.a
-_servald.a: $(SERVALD_OBJS) $(OBJSDIR_TOOLS)/version.o
+_servald.a:	$(SERVALD_OBJS) \
+		$(OBJSDIR_TOOLS)/version.o \
+		$(OBJSDIR_SERVALD)/servald_features.o
 	@echo AR $@
 	@$(RM) $@
 	@$(AR) -cr $@ $^
 
-libservaldaemon.a: _servald.a $(LIBSODIUM_A)
-	@$(call MERGE_STATIC_LIBS, $@, $^)
-
+# The daemon shared library.  This is linked in at run-time by the JNI
+# interface using dlopen(3).  The servald_features.o object is explicitly
+# included here, even though it is also available in libservaldaemon.a, because
+# without it, many feature-specific .o object files would not be pulled into
+# the shared library, and the Java API would then fail at run-time with errors
+# like:
+# java.lang.UnsatisfiedLinkError: libservaldaemon.so: undefined symbol: __stop_httpd
 libservaldaemon.so: \
 		$(OBJSDIR_SERVALD)/servald_features.o \
 		$(OBJSDIR_SERVALD)/log_output_console.o \
 		$(SERVAL_DAEMON_JNI_OBJS) \
-		_servald.a \
-		$(LIBSODIUM_A)
+		libservaldaemon.a
 	@echo LINK $@
 	@$(CC) -Wall -shared -o $@ $(LDFLAGS) $(filter %.o, $^) $(filter %.a, $^)
 
diff --git a/headerfiles.mk b/headerfiles.mk
index a0b38dbf..aa4cf242 100644
--- a/headerfiles.mk
+++ b/headerfiles.mk
@@ -33,6 +33,7 @@ LIB_HDRS= \
 # are exposed by the iOS framework module, so they are accessible to Swift code
 # in Xcode projects.
 PUBLIC_HDRS= \
+	servald_features.h \
 	commandline.h \
 	constants.h \
 	conf.h \
diff --git a/servald_features.c b/servald_features.c
index 3a784ad1..681dd60a 100644
--- a/servald_features.c
+++ b/servald_features.c
@@ -17,6 +17,7 @@ along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 
+#include "servald_features.h"
 #include "feature.h"
 
 void servald_features()
diff --git a/servald_features.h b/servald_features.h
new file mode 100644
index 00000000..56ec4642
--- /dev/null
+++ b/servald_features.h
@@ -0,0 +1,20 @@
+/*
+Serval DNA daemon features
+Copyright (C) 2018 Flinders University
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+*/
+
+void servald_features();