Implement symbol versioning

Restrict visibility of symbols to the symbols we actually want to be
public.

configure.ac

@@ -441,6 +441,10 @@ AC_SUBST(VARNISH_STATE_DIR)
 # Default configuration directory.
 varnishconfdir='${sysconfdir}/varnish'
 AC_SUBST(varnishconfdir)
+
+# Check for linker script support
+gl_LD_VERSION_SCRIPT
+
 # Now that we're done using the compiler to look for functions and
 # libraries, set CFLAGS to what we want them to be for our own code
 

lib/libvarnishapi/Makefile.am

@@ -24,9 +24,16 @@ libvarnishapi_la_SOURCES = \
 	vsm.c \
 	vsl_arg.c \
 	vsl.c \
-	vsc.c
+	vsc.c \
+	libvarnishapi.map
 
 libvarnishapi_la_CFLAGS = \
 	-DVARNISH_STATE_DIR='"${VARNISH_STATE_DIR}"'
 
 libvarnishapi_la_LIBADD = @PCRE_LIBS@
+
+if HAVE_LD_VERSION_SCRIPT
+libvarnishapi_la_LDFLAGS += -Wl,--version-script=$(srcdir)/libvarnishapi.map
+else
+libvarnishapi_la_LDFLAGS += -export-symbols-regex '^V'
+endif

lib/libvarnishapi/libvarnishapi.map

+/*-
+ * Copyright (c) 2011 Varnish Software AS
+ * All rights reserved.
+ *
+ * Author: Tollef Fog Heen <tfheen@varnish-software.com> 
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+LIBVARNISHAPI_1.0 {
+  global:
+	# Functions
+	VSM_New;
+	VSM_Diag;
+	VSM_n_Arg;
+	VSM_Name;
+	VSM_Delete;
+	VSM_Open;
+	VSM_ReOpen;
+	VSM_Seq;
+	VSM_Head;
+	VSM_Find_Chunk;
+	VSM_Close;
+	VSM_iter0;
+	VSM_intern;
+	
+	VSC_Setup;
+	VSC_Arg;
+	VSC_Open;
+	VSC_Main;
+	VSC_Iter;
+
+	VSL_Setup;
+	VSL_Open;
+	VSL_Arg;
+	VSL_H_Print;
+	VSL_Select;
+	VSL_NonBlocking;
+	VSL_Dispatch;
+	VSL_NextLog;
+	VSL_Matched;
+
+	VCLI_WriteResult;
+	VCLI_ReadResult;
+	VCLI_AuthResponse;
+
+	# Variables
+	VSL_tags;
+  local:
+	*;
+};

m4/ld-version-script.m4

+# ld-version-script.m4 serial 1
+dnl Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson
+
+# FIXME: The test below returns a false positive for mingw
+# cross-compiles, 'local:' statements does not reduce number of
+# exported symbols in a DLL.  Use --disable-ld-version-script to work
+# around the problem.
+
+# gl_LD_VERSION_SCRIPT
+# --------------------
+# Check if LD supports linker scripts, and define automake conditional
+# HAVE_LD_VERSION_SCRIPT if so.
+AC_DEFUN([gl_LD_VERSION_SCRIPT],
+[
+  AC_ARG_ENABLE([ld-version-script],
+    AS_HELP_STRING([--enable-ld-version-script],
+      [enable linker version script (default is enabled when possible)]),
+      [have_ld_version_script=$enableval], [])
+  if test -z "$have_ld_version_script"; then
+    AC_MSG_CHECKING([if LD -Wl,--version-script works])
+    save_LDFLAGS="$LDFLAGS"
+    LDFLAGS="$LDFLAGS -Wl,--version-script=conftest.map"
+    cat > conftest.map <<EOF
+VERS_1 {
+	global: sym;
+};
+
+VERS_2 {
+        global: sym;
+} VERS_1;
+EOF
+    AC_LINK_IFELSE(AC_LANG_PROGRAM([], []),
+                   [have_ld_version_script=yes], [have_ld_version_script=no])
+    rm -f conftest.map
+    LDFLAGS="$save_LDFLAGS"
+    AC_MSG_RESULT($have_ld_version_script)
+  fi
+  AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
+])