code.delx.au - pulseaudio/blob - src/daemon/ltdl-bind-now.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2004-2006 Lennart Poettering
   7   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   8
   9   PulseAudio is free software; you can redistribute it and/or modify
  10   it under the terms of the GNU Lesser General Public License as published
  11   by the Free Software Foundation; either version 2 of the License,
  12   or (at your option) any later version.
  13
  14   PulseAudio is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with PulseAudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include <config.h>
  27 #endif
  28
  29 #if HAVE_DLFCN_H
  30 #include <dlfcn.h>
  31 #endif
  32
  33 #if HAVE_SYS_DL_H
  34 #include <sys/dl.h>
  35 #endif
  36
  37 #include <ltdl.h>
  38
  39 #include <pulsecore/macro.h>
  40 #include <pulsecore/mutex.h>
  41 #include <pulsecore/thread.h>
  42 #include <pulsecore/log.h>
  43
  44 #include "ltdl-bind-now.h"
  45
  46 #ifdef RTLD_NOW
  47 #define PA_BIND_NOW RTLD_NOW
  48 #elif defined(DL_NOW)
  49 #define PA_BIND_NOW DL_NOW
  50 #else
  51 #undef PA_BIND_NOW
  52 #endif
  53
  54 static pa_mutex *libtool_mutex = NULL;
  55
  56 PA_STATIC_TLS_DECLARE_NO_FREE(libtool_tls);
  57
  58 static void libtool_lock(void) {
  59     pa_mutex_lock(libtool_mutex);
  60 }
  61
  62 static void libtool_unlock(void) {
  63     pa_mutex_unlock(libtool_mutex);
  64 }
  65
  66 static void libtool_set_error(const char *error) {
  67     PA_STATIC_TLS_SET(libtool_tls, (char*) error);
  68 }
  69
  70 static const char *libtool_get_error(void) {
  71     return PA_STATIC_TLS_GET(libtool_tls);
  72 }
  73
  74 #ifdef PA_BIND_NOW
  75
  76 /*
  77   To avoid lazy relocations during runtime in our RT threads we add
  78   our own shared object loader with uses RTLD_NOW if it is
  79   available. The standard ltdl loader prefers RTLD_LAZY.
  80
  81   Please note that this loader doesn't have any influence on
  82   relocations on any libraries that are already loaded into our
  83   process, i.e. because the pulseaudio binary links directly to
  84   them. To disable lazy relocations for those libraries it is possible
  85   to set $LT_BIND_NOW before starting the pulsaudio binary.
  86 */
  87
  88 static lt_module bind_now_open(lt_user_data d, const char *fname) {
  89     lt_module m;
  90
  91     pa_assert(fname);
  92
  93     if (!(m = dlopen(fname, PA_BIND_NOW))) {
  94         libtool_set_error(dlerror());
  95         return NULL;
  96     }
  97
  98     return m;
  99 }
 100
 101 static int bind_now_close(lt_user_data d, lt_module m) {
 102
 103     pa_assert(m);
 104
 105     if (dlclose(m) != 0){
 106         libtool_set_error(dlerror());
 107         return 1;
 108     }
 109
 110     return 0;
 111 }
 112
 113 static lt_ptr bind_now_find_sym(lt_user_data d, lt_module m, const char *symbol) {
 114     lt_ptr ptr;
 115
 116     pa_assert(m);
 117     pa_assert(symbol);
 118
 119     if (!(ptr = dlsym(m, symbol))) {
 120         libtool_set_error(dlerror());
 121         return NULL;
 122     }
 123
 124     return ptr;
 125 }
 126
 127 #endif
 128
 129 void pa_ltdl_init(void) {
 130
 131 #ifdef PA_BIND_NOW
 132     lt_dlloader *place;
 133     static const struct lt_user_dlloader loader = {
 134         .module_open = bind_now_open,
 135         .module_close = bind_now_close,
 136         .find_sym = bind_now_find_sym
 137     };
 138 #endif
 139
 140     pa_assert_se(lt_dlinit() == 0);
 141     pa_assert_se(libtool_mutex = pa_mutex_new(TRUE, FALSE));
 142     pa_assert_se(lt_dlmutex_register(libtool_lock, libtool_unlock, libtool_set_error, libtool_get_error) == 0);
 143
 144 #ifdef PA_BIND_NOW
 145
 146     if (!(place = lt_dlloader_find("dlopen")))
 147         place = lt_dlloader_next(NULL);
 148
 149     /* Add our BIND_NOW loader as the default module loader. */
 150     if (lt_dlloader_add(place, &loader, "bind-now-loader") != 0)
 151         pa_log_warn("Failed to add bind-now-loader.");
 152 #endif
 153 }
 154
 155 void pa_ltdl_done(void) {
 156     pa_assert_se(lt_dlexit() == 0);
 157     pa_mutex_free(libtool_mutex);
 158     libtool_mutex = NULL;
 159 }
 160