Add symbol versioning to libopenconnect shared library

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Makefile.am

@@ -24,11 +24,15 @@ libopenconnect_la_LIBADD = $(OPENSSL_LIBS) $(LIBXML2_LIBS) $(LIBPROXY_LIBS) $(LI
 libopenconnect_la_LDFLAGS = -version-number 1:4
 noinst_HEADERS = openconnect-internal.h openconnect.h
 include_HEADERS = openconnect.h
+if HAVE_SYMBOL_VERSIONING
+libopenconnect_la_LDFLAGS += -Wl,--version-script,libopenconnect.map
+libopenconnect_la_DEPENDENCIES = libopenconnect.map
+endif
 
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = openconnect.pc
 
-EXTRA_DIST = version.sh openconnect.8 COPYING.LGPL
+EXTRA_DIST = version.sh openconnect.8 COPYING.LGPL libopenconnect.map
 
 DISTCLEANFILES = $(pkgconfig_DATA)
 

configure.ac

@@ -188,6 +188,25 @@ AC_ARG_WITH([openssl],
 # Needs to happen after we default to static/shared libraries based on OpenSSL
 AC_PROG_LIBTOOL
 
+# Ick. This seems like it's likely to be very fragile, but I can't see a better
+# way. I shall console myself with the observation that the failure mode isn't
+# particularly horrible — you just don't get symbol versioning if it fails.
+symvers=no
+if test "$enable_shared" = "yes" ; then
+   AC_MSG_CHECKING([if library symbol versioning is available]);
+   echo 'FOO { global: foo; };' > conftest.map
+   echo 'int foo = 0;' > conftest.$ac_ext
+   if AC_TRY_EVAL(ac_compile); then
+      soname=conftest
+      libobjs=conftest.$ac_objext
+      if AC_TRY_EVAL(archive_cmds ${wl}--version-script ${wl}conftest.map); then
+         symvers=yes
+      fi
+   fi
+   AC_MSG_RESULT(${symvers})
+fi
+AM_CONDITIONAL(HAVE_SYMBOL_VERSIONING, [test "${symvers}" = "yes"])
+
 PKG_CHECK_MODULES(LIBXML2, libxml-2.0)
 
 PKG_CHECK_MODULES(ZLIB, zlib, [],

libopenconnect.map

@@ -0,0 +1,50 @@
+OPENCONNECT_1.2 {
+ global:
+	openconnect_clear_cookie;
+	openconnect_get_cert_sha1;
+	openconnect_get_cookie;
+	openconnect_get_hostname;
+	openconnect_get_peer_cert;
+	openconnect_get_port;
+	openconnect_get_urlpath;
+	openconnect_get_version;
+	openconnect_init_openssl;
+	openconnect_obtain_cookie;
+	openconnect_parse_url;
+	openconnect_passphrase_from_fsid;
+	openconnect_reset_ssl;
+	openconnect_set_cafile;
+	openconnect_set_client_cert;
+	openconnect_set_hostname;
+	openconnect_set_http_proxy;
+	openconnect_setup_csd;
+	openconnect_set_urlpath;
+	openconnect_set_xmlsha1;
+	openconnect_vpninfo_free;
+	openconnect_vpninfo_new;
+	openconnect_vpninfo_new_with_cbdata;
+ local:
+	*;
+};
+
+OPENCONNECT_1.3 {
+ global:
+	openconnect_set_cert_expiry_warning;
+} OPENCONNECT_1.2;
+
+OPENCONNECT_1.4 {
+ global:
+	openconnect_set_cancel_fd;
+} OPENCONNECT_1.3;
+
+OPENCONNECT_PRIVATE {
+ global:
+	openconnect_SSL_gets;
+	openconnect_close_https;
+	openconnect_open_https;
+	openconnect_SSL_printf;
+	openconnect_version_str;
+	openconnect_create_useragent;
+	internal_parse_url;
+	report_ssl_errors;
+};