waf: use -Wl,--version-script if available

This enables symbol version on our libraries, if the system supports
it

If the library is a public library, then set the symbol version based
on the major number. If it is a private library then set it based on
the full version number (which will include the git hash if
available).

This ensures that applications using our libraries don't use symbols
from other libraries that they may be linked to. It also ensures we
only use the right version of any private libraries.

Note that the linker ends up generating both a version and unversioned
symbol for all symbols. This means existing users of our public
libraries will continue to work, with symbols resolved to the
unversioned symbol. When applications are re-linked they will bind to
the specific symbol version.

Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>
Pair-Programmed-With: Jelmer Vernooij <jelmer@samba.org>

2 files changed, 19 insertions, 2 deletions

diff --git a/buildtools/wafsamba/samba_deps.py b/buildtools/wafsamba/samba_deps.py
index 91737d5873..0ea966033c 100644
--- a/buildtools/wafsamba/samba_deps.py
+++ b/buildtools/wafsamba/samba_deps.py
@@ -952,7 +952,8 @@ def show_object_duplicates(bld, tgt_list):
 ######################################################################
 # this provides a way to save our dependency calculations between runs
 savedeps_version = 3
-savedeps_inputs  = ['samba_deps', 'samba_includes', 'local_include', 'local_include_first', 'samba_cflags', 'source', 'grouping_library']
+savedeps_inputs  = ['samba_deps', 'samba_includes', 'local_include', 'local_include_first', 'samba_cflags',
+                    'source', 'grouping_library', 'ldflags']
 savedeps_outputs = ['uselib', 'uselib_local', 'add_objects', 'includes', 'ccflags', 'ldflags', 'samba_deps_extended']
 savedeps_outenv  = ['INC_PATHS']
 savedeps_envvars = ['NONSHARED_BINARIES', 'GLOBAL_DEPENDENCIES', 'EXTRA_CFLAGS', 'EXTRA_LDFLAGS' ]
diff --git a/buildtools/wafsamba/wafsamba.py b/buildtools/wafsamba/wafsamba.py
index 10b7dfe0f4..fc75def98d 100644
--- a/buildtools/wafsamba/wafsamba.py
+++ b/buildtools/wafsamba/wafsamba.py
@@ -103,6 +103,7 @@ def SAMBA_LIBRARY(bld, libname, source,
                   vnum=None,
                   soname=None,
                   cflags='',
+                  ldflags='',
                   external_library=False,
                   realname=None,
                   autoproto=None,
@@ -188,11 +189,24 @@ def SAMBA_LIBRARY(bld, libname, source,
     else:
         bundled_name = PRIVATE_NAME(bld, libname, bundled_extension, private_library)
 
+    ldflags = TO_LIST(ldflags)
+
     if private_library:
         if vnum:
             Logs.error("vnum is invalid for private libraries")
             sys.exit(1)
-        vnum = Utils.g_module.VERSION[0]
+        vnum = Utils.g_module.VERSION.split(".")[0]
+        version = "%s_%s" % (Utils.g_module.APPNAME, Utils.g_module.VERSION)
+    else:
+        version = "%s_%s" % (Utils.g_module.APPNAME, Utils.g_module.VERSION.split(".")[0])
+
+    if bld.env.HAVE_LD_VERSION_SCRIPT:
+        vscript = "%s.vscript" % libname
+        bld.SAMBA_GENERATOR(vscript,
+                            rule="echo %s \{ global: \*\; \}\; > ${TGT}" % version.replace("-","_").upper(),
+                            group='vscripts',
+                            target=vscript)
+        ldflags.append("-Wl,--version-script=%s/%s" % (bld.path.abspath(bld.env), vscript))
 
     features = 'cc cshlib symlink_lib install_lib'
     if target_type == 'PYTHON':
@@ -213,6 +227,7 @@ def SAMBA_LIBRARY(bld, libname, source,
         source          = [],
         target          = bundled_name,
         depends_on      = depends_on,
+        ldflags		= ldflags,
         samba_deps      = deps,
         samba_includes  = includes,
         local_include   = local_include,
@@ -525,6 +540,7 @@ def SETUP_BUILD_GROUPS(bld):
     bld.env['USING_BUILD_GROUPS'] = True
     bld.add_group('setup')
     bld.add_group('build_compiler_source')
+    bld.add_group('vscripts')
     bld.add_group('base_libraries')
     bld.add_group('generators')
     bld.add_group('compiler_prototypes')