Add a special ltdl .so loader that avoids lazy frelocations during runtime

git-svn-id: file:///home/lennart/svn/public/pulseaudio/branches/lennart@1838 fefdeb5f-60dc-0310-8127-8f9354f1896f

configure.ac

@@ -187,7 +187,7 @@ AC_HEADER_STDC
 AC_CHECK_HEADERS([arpa/inet.h glob.h grp.h netdb.h netinet/in.h \
     netinet/in_systm.h netinet/tcp.h pwd.h sched.h \
     sys/mman.h sys/resource.h sys/select.h sys/socket.h sys/wait.h \
-    syslog.h])
+    syslog.h sys/dl.h dlfcn.h])
 AC_CHECK_HEADERS([netinet/ip.h], [], [],
 		 [#include <sys/types.h>
 		  #if HAVE_NETINET_IN_H

src/Makefile.am

@@ -132,6 +132,7 @@ pulseaudio_SOURCES = \
 		daemon/cpulimit.c daemon/cpulimit.h \
 		daemon/daemon-conf.c daemon/daemon-conf.h \
 		daemon/dumpmodules.c daemon/dumpmodules.h \
+		daemon/ltdl-bind-now.c daemon/ltdl-bind-now.h \
 		daemon/main.c \
 		pulsecore/gccmacro.h
 

src/daemon/ltdl-bind-now.c

@@ -0,0 +1,160 @@
+/* $Id$ */
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2004-2006 Lennart Poettering
+  Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as published
+  by the Free Software Foundation; either version 2 of the License,
+  or (at your option) any later version.
+
+  PulseAudio 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 Lesser General Public License
+  along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+
+#if HAVE_SYS_DL_H
+#include <sys/dl.h>
+#endif
+
+#include <ltdl.h>
+
+#include <pulsecore/macro.h>
+#include <pulsecore/mutex.h>
+#include <pulsecore/thread.h>
+#include <pulsecore/log.h>
+
+#include "ltdl-bind-now.h"
+
+#ifdef RTLD_NOW
+#define PA_BIND_NOW RTLD_NOW
+#elif defined(DL_NOW)
+#define PA_BIND_NOW DL_NOW
+#else
+#undef PA_BIND_NOW
+#endif
+
+static pa_mutex *libtool_mutex = NULL;
+
+PA_STATIC_TLS_DECLARE_NO_FREE(libtool_tls);
+
+static void libtool_lock(void) {
+    pa_mutex_lock(libtool_mutex);
+}
+
+static void libtool_unlock(void) {
+    pa_mutex_unlock(libtool_mutex);
+}
+
+static void libtool_set_error(const char *error) {
+    PA_STATIC_TLS_SET(libtool_tls, (char*) error);
+}
+
+static const char *libtool_get_error(void) {
+    return PA_STATIC_TLS_GET(libtool_tls);
+}
+
+#ifdef PA_BIND_NOW
+
+/*
+  To avoid lazy relocations during runtime in our RT threads we add
+  our own shared object loader with uses RTLD_NOW if it is
+  available. The standard ltdl loader prefers RTLD_LAZY.
+
+  Please note that this loader doesn't have any influence on
+  relocations on any libraries that are already loaded into our
+  process, i.e. because the pulseaudio binary links directly to
+  them. To disable lazy relocations for those libraries it is possible
+  to set $LT_BIND_NOW before starting the pulsaudio binary.
+*/
+
+static lt_module bind_now_open(lt_user_data d, const char *fname) {
+    lt_module m;
+
+    pa_assert(fname);
+
+    if (!(m = dlopen(fname, PA_BIND_NOW))) {
+        libtool_set_error(dlerror());
+        return NULL;
+    }
+
+    return m;
+}
+
+static int bind_now_close(lt_user_data d, lt_module m) {
+
+    pa_assert(m);
+
+    if (dlclose(m) != 0){
+        libtool_set_error(dlerror());
+        return 1;
+    }
+
+    return 0;
+}
+
+static lt_ptr bind_now_find_sym(lt_user_data d, lt_module m, const char *symbol) {
+    lt_ptr ptr;
+
+    pa_assert(m);
+    pa_assert(symbol);
+    
+    if (!(ptr = dlsym(m, symbol))) {
+        libtool_set_error(dlerror());
+        return NULL;
+    }
+
+    return ptr;
+}
+
+#endif
+
+void pa_ltdl_init(void) {
+
+#ifdef PA_BIND_NOW
+    lt_dlloader *place;
+    static const struct lt_user_dlloader loader = {
+        .module_open = bind_now_open,
+        .module_close = bind_now_close,
+        .find_sym = bind_now_find_sym
+    };
+#endif
+    
+    pa_assert_se(lt_dlinit() == 0);       
+    pa_assert_se(libtool_mutex = pa_mutex_new(TRUE, FALSE));
+    pa_assert_se(lt_dlmutex_register(libtool_lock, libtool_unlock, libtool_set_error, libtool_get_error) == 0);
+
+#ifdef PA_BIND_NOW
+
+    if (!(place = lt_dlloader_find("dlopen")))
+        place = lt_dlloader_next(NULL);
+    
+    /* Add our BIND_NOW loader as the default module loader. */
+    if (lt_dlloader_add(place, &loader, "bind-now-loader") != 0)
+        pa_log_warn("Failed to add bind-now-loader.");
+#endif
+}
+
+void pa_ltdl_done(void) {
+    pa_assert_se(lt_dlexit() == 0);
+    pa_mutex_free(libtool_mutex);
+    libtool_mutex = NULL;
+}
+

src/daemon/ltdl-bind-now.h

@@ -0,0 +1,32 @@
+#ifndef foopulsecoreltdlbindnowhfoo
+#define foopulsecoreltdlbindnowhfoo
+
+/* $Id$ */
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2004-2006 Lennart Poettering
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as published
+  by the Free Software Foundation; either version 2 of the License,
+  or (at your option) any later version.
+
+  PulseAudio 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 Lesser General Public License
+  along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+
+void pa_ltdl_init(void);
+void pa_ltdl_done(void);
+
+#endif
+

src/daemon/main.c

@@ -93,6 +93,7 @@
 #include "daemon-conf.h"
 #include "dumpmodules.h"
 #include "caps.h"
+#include "ltdl-bind-now.h"
 
 #ifdef HAVE_LIBWRAP
 /* Only one instance of these variables */
@@ -309,38 +310,6 @@ static void set_all_rlimits(const pa_daemon_conf *conf) {
 }
 #endif
 
-static pa_mutex *libtool_mutex = NULL;
-        
-static void libtool_lock(void) {
-    pa_mutex_lock(libtool_mutex);
-}
-
-static void libtool_unlock(void) {
-    pa_mutex_unlock(libtool_mutex);
-}
-
-PA_STATIC_TLS_DECLARE_NO_FREE(libtool_tls);
-
-static void libtool_set_error(const char * error) {
-    PA_STATIC_TLS_SET(libtool_tls, (char*) error);
-}
-
-static const char *libtool_get_error(void) {
-    return PA_STATIC_TLS_GET(libtool_tls);
-}
-
-static void libtool_init(void)  {
-    pa_assert_se(libtool_mutex = pa_mutex_new(TRUE, FALSE));
-    pa_assert_se(lt_dlmutex_register(libtool_lock, libtool_unlock, libtool_set_error, libtool_get_error) == 0);
-    pa_assert_se(lt_dlinit() == 0);
-}
-
-static void libtool_done(void) {
-    pa_assert_se(lt_dlexit() == 0);
-    pa_mutex_free(libtool_mutex);
-    libtool_mutex = NULL;
-}
-
 int main(int argc, char *argv[]) {
     pa_core *c = NULL;
     pa_strbuf *buf = NULL;
@@ -396,7 +365,7 @@ int main(int argc, char *argv[]) {
 
     LTDL_SET_PRELOADED_SYMBOLS();
 
-    libtool_init();
+    pa_ltdl_init();
 
 #ifdef OS_IS_WIN32
     {
@@ -747,7 +716,7 @@ finish:
     WSACleanup();
 #endif
 
-    libtool_done();
+    pa_ltdl_done();
 
 #ifdef HAVE_DBUS
     dbus_shutdown();