From 4a0b6d659d2fb0473b75cf53bb1a0934983d270c Mon Sep 17 00:00:00 2001
From: Tobias Brunner <tobias@strongswan.org>
Date: Fri, 28 Apr 2017 17:49:50 +0200
Subject: [PATCH] Add plugin constructor registration for all libraries that
 provide plugins

Unfortunately, we can't just add the generated C file to the sources in
Makefile.am as the linker would remove that object file when it notices
that no symbol in it is ever referenced.  So we include it in the file
that contains the library initialization, which will definitely be
referenced by the executable.

This allows building an almost stand-alone static version of e.g. charon
when building with `--enable-monolithic --enable-static --disable-shared`
(without `--disable-shared` libtool will only build a version that links
the libraries dynamically).  External libraries (e.g. gmp or openssl) are
not linked statically this way, though.
---
 .gitignore                    | 1 +
 src/libcharon/Makefile.am     | 9 +++++++++
 src/libcharon/daemon.c        | 7 +++++++
 src/libstrongswan/Makefile.am | 9 +++++++++
 src/libstrongswan/library.c   | 7 +++++++
 src/libtnccs/Makefile.am      | 9 +++++++++
 src/libtnccs/tnc/tnc.c        | 7 +++++++
 src/libtpmtss/Makefile.am     | 9 +++++++++
 src/libtpmtss/tpm_tss.c       | 7 +++++++
 9 files changed, 65 insertions(+)

diff --git a/.gitignore b/.gitignore
index 2e4541576..cd0c30728 100644
--- a/.gitignore
+++ b/.gitignore
@@ -27,6 +27,7 @@ libtool
 y.tab.[ch]
 lex.yy.c
 *keywords.c
+plugin_constructors.c
 Doxyfile
 apidoc/
 *~
diff --git a/src/libcharon/Makefile.am b/src/libcharon/Makefile.am
index 8461d6230..3fcaedc3b 100644
--- a/src/libcharon/Makefile.am
+++ b/src/libcharon/Makefile.am
@@ -184,6 +184,15 @@ if USE_ME
     sa/ikev2/tasks/ike_me.c sa/ikev2/tasks/ike_me.h
 endif
 
+if STATIC_PLUGIN_CONSTRUCTORS
+BUILT_SOURCES = $(srcdir)/plugin_constructors.c
+CLEANFILES = $(srcdir)/plugin_constructors.c
+
+$(srcdir)/plugin_constructors.c: $(top_srcdir)/src/libstrongswan/plugins/plugin_constructors.py
+		$(AM_V_GEN) \
+		$(PYTHON) $(top_srcdir)/src/libstrongswan/plugins/plugin_constructors.py ${c_plugins} > $@
+endif
+
 # build optional plugins
 ########################
 
diff --git a/src/libcharon/daemon.c b/src/libcharon/daemon.c
index eadc10a6a..8daea783f 100644
--- a/src/libcharon/daemon.c
+++ b/src/libcharon/daemon.c
@@ -117,6 +117,13 @@ struct private_daemon_t {
 	refcount_t ref;
 };
 
+/**
+ * Register plugins if built statically
+ */
+#ifdef STATIC_PLUGIN_CONSTRUCTORS
+#include "plugin_constructors.c"
+#endif
+
 /**
  * One and only instance of the daemon.
  */
diff --git a/src/libstrongswan/Makefile.am b/src/libstrongswan/Makefile.am
index 69abfbe0e..b4d8452f1 100644
--- a/src/libstrongswan/Makefile.am
+++ b/src/libstrongswan/Makefile.am
@@ -221,6 +221,15 @@ $(srcdir)/crypto/proposal/proposal_keywords_static.c:	$(srcdir)/crypto/proposal/
 		$(GPERF) -N proposal_get_token_static -m 10 -C -G -c -t -D < \
 												$(srcdir)/crypto/proposal/proposal_keywords_static.txt > $@
 
+if STATIC_PLUGIN_CONSTRUCTORS
+BUILT_SOURCES += $(srcdir)/plugin_constructors.c
+CLEANFILES = $(srcdir)/plugin_constructors.c
+
+$(srcdir)/plugin_constructors.c: $(srcdir)/plugins/plugin_constructors.py
+		$(AM_V_GEN) \
+		$(PYTHON) $(srcdir)/plugins/plugin_constructors.py ${s_plugins} > $@
+endif
+
 if MONOLITHIC
 SUBDIRS =
 else
diff --git a/src/libstrongswan/library.c b/src/libstrongswan/library.c
index 1d1e1f07e..7944b9356 100644
--- a/src/libstrongswan/library.c
+++ b/src/libstrongswan/library.c
@@ -93,6 +93,13 @@ void library_add_namespace(char *ns)
 	}
 }
 
+/**
+ * Register plugins if built statically
+ */
+#ifdef STATIC_PLUGIN_CONSTRUCTORS
+#include "plugin_constructors.c"
+#endif
+
 /**
  * library instance
  */
diff --git a/src/libtnccs/Makefile.am b/src/libtnccs/Makefile.am
index 7a630fe54..ff7b54f6a 100644
--- a/src/libtnccs/Makefile.am
+++ b/src/libtnccs/Makefile.am
@@ -26,6 +26,15 @@ tnc/tnccs/tnccs_manager.h tnc/tnccs/tnccs_manager.c
 
 EXTRA_DIST = Android.mk
 
+if STATIC_PLUGIN_CONSTRUCTORS
+BUILT_SOURCES = $(srcdir)/plugin_constructors.c
+CLEANFILES = $(srcdir)/plugin_constructors.c
+
+$(srcdir)/plugin_constructors.c: $(top_srcdir)/src/libstrongswan/plugins/plugin_constructors.py
+		$(AM_V_GEN) \
+		$(PYTHON) $(top_srcdir)/src/libstrongswan/plugins/plugin_constructors.py ${t_plugins} > $@
+endif
+
 # build optional plugins
 ########################
 
diff --git a/src/libtnccs/tnc/tnc.c b/src/libtnccs/tnc/tnc.c
index 80ba61c5a..9627be862 100644
--- a/src/libtnccs/tnc/tnc.c
+++ b/src/libtnccs/tnc/tnc.c
@@ -54,6 +54,13 @@ struct private_tnc_t {
 	refcount_t ref;
 };
 
+/**
+ * Register plugins if built statically
+ */
+#ifdef STATIC_PLUGIN_CONSTRUCTORS
+#include "plugin_constructors.c"
+#endif
+
 /**
  * Single instance of tnc_t.
  */
diff --git a/src/libtpmtss/Makefile.am b/src/libtpmtss/Makefile.am
index c7ac39a09..5f3a97a99 100644
--- a/src/libtpmtss/Makefile.am
+++ b/src/libtpmtss/Makefile.am
@@ -33,6 +33,15 @@ else
 SUBDIRS = .
 endif
 
+if STATIC_PLUGIN_CONSTRUCTORS
+BUILT_SOURCES = $(srcdir)/plugin_constructors.c
+CLEANFILES = $(srcdir)/plugin_constructors.c
+
+$(srcdir)/plugin_constructors.c: $(top_srcdir)/src/libstrongswan/plugins/plugin_constructors.py
+		$(AM_V_GEN) \
+		$(PYTHON) $(top_srcdir)/src/libstrongswan/plugins/plugin_constructors.py ${p_plugins} > $@
+endif
+
 if USE_TPM
   SUBDIRS += plugins/tpm
 if MONOLITHIC
diff --git a/src/libtpmtss/tpm_tss.c b/src/libtpmtss/tpm_tss.c
index b7b970c8d..42a341896 100644
--- a/src/libtpmtss/tpm_tss.c
+++ b/src/libtpmtss/tpm_tss.c
@@ -17,6 +17,13 @@
 #include "tpm_tss_tss2.h"
 #include "tpm_tss_trousers.h"
 
+/**
+ * Register plugins if built statically
+ */
+#ifdef STATIC_PLUGIN_CONSTRUCTORS
+#include "plugin_constructors.c"
+#endif
+
 /**
  * Described in header.
  */