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

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2004-2006 Lennart Poettering
   5   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   6
   7   PulseAudio is free software; you can redistribute it and/or modify
   8   it under the terms of the GNU Lesser General Public License as published
   9   by the Free Software Foundation; either version 2 of the License,
  10   or (at your option) any later version.
  11
  12   PulseAudio is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with PulseAudio; if not, write to the Free Software
  19   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  20   USA.
  21 ***/
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #if HAVE_DLFCN_H
  28 #include <dlfcn.h>
  29 #endif
  30
  31 #if HAVE_SYS_DL_H
  32 #include <sys/dl.h>
  33 #endif
  34
  35 #include <string.h>
  36
  37 #include <ltdl.h>
  38
  39 #include <pulse/i18n.h>
  40
  41 #include <pulsecore/macro.h>
  42 #include <pulsecore/mutex.h>
  43 #include <pulsecore/thread.h>
  44 #include <pulsecore/log.h>
  45
  46 #include "ltdl-bind-now.h"
  47
  48 #ifdef RTLD_NOW
  49 #define PA_BIND_NOW RTLD_NOW
  50 #elif defined(DL_NOW)
  51 #define PA_BIND_NOW DL_NOW
  52 #else
  53 #undef PA_BIND_NOW
  54 #endif
  55
  56 #ifdef HAVE_LT_DLMUTEX_REGISTER
  57
  58 static pa_mutex *libtool_mutex = NULL;
  59
  60 PA_STATIC_TLS_DECLARE_NO_FREE(libtool_tls);
  61
  62 static void libtool_lock(void) {
  63     pa_mutex_lock(libtool_mutex);
  64 }
  65
  66 static void libtool_unlock(void) {
  67     pa_mutex_unlock(libtool_mutex);
  68 }
  69
  70 static void libtool_set_error(const char *error) {
  71     PA_STATIC_TLS_SET(libtool_tls, (char*) error);
  72 }
  73
  74 static const char *libtool_get_error(void) {
  75     return PA_STATIC_TLS_GET(libtool_tls);
  76 }
  77
  78 #endif
  79
  80 #ifdef PA_BIND_NOW
  81
  82 /*
  83   To avoid lazy relocations during runtime in our RT threads we add
  84   our own shared object loader with uses RTLD_NOW if it is
  85   available. The standard ltdl loader prefers RTLD_LAZY.
  86
  87   Please note that this loader doesn't have any influence on
  88   relocations on any libraries that are already loaded into our
  89   process, i.e. because the pulseaudio binary links directly to
  90   them. To disable lazy relocations for those libraries it is possible
  91   to set $LT_BIND_NOW before starting the pulsaudio binary.
  92 */
  93
  94 #ifndef HAVE_LT_DLADVISE
  95 static lt_module bind_now_open(lt_user_data d, const char *fname)
  96 #else
  97 static lt_module bind_now_open(lt_user_data d, const char *fname, lt_dladvise advise)
  98 #endif
  99 {
 100     lt_module m;
 101
 102     pa_assert(fname);
 103
 104     if (!(m = dlopen(fname, PA_BIND_NOW))) {
 105         libtool_set_error(dlerror());
 106         return NULL;
 107     }
 108
 109     return m;
 110 }
 111
 112 static int bind_now_close(lt_user_data d, lt_module m) {
 113
 114     pa_assert(m);
 115
 116     if (dlclose(m) != 0){
 117         libtool_set_error(dlerror());
 118         return 1;
 119     }
 120
 121     return 0;
 122 }
 123
 124 static lt_ptr bind_now_find_sym(lt_user_data d, lt_module m, const char *symbol) {
 125     lt_ptr ptr;
 126
 127     pa_assert(m);
 128     pa_assert(symbol);
 129
 130     if (!(ptr = dlsym(m, symbol))) {
 131         libtool_set_error(dlerror());
 132         return NULL;
 133     }
 134
 135     return ptr;
 136 }
 137
 138 #endif
 139
 140 void pa_ltdl_init(void) {
 141
 142 #ifdef PA_BIND_NOW
 143 # ifdef HAVE_STRUCT_LT_USER_DLLOADER
 144     lt_dlloader *place;
 145     static const struct lt_user_dlloader loader = {
 146         .module_open = bind_now_open,
 147         .module_close = bind_now_close,
 148         .find_sym = bind_now_find_sym
 149     };
 150 # else
 151     static const lt_dlvtable *dlopen_loader;
 152     static lt_dlvtable bindnow_loader;
 153 # endif
 154 #endif
 155
 156     pa_assert_se(lt_dlinit() == 0);
 157
 158 #ifdef HAVE_LT_DLMUTEX_REGISTER
 159     pa_assert_se(libtool_mutex = pa_mutex_new(TRUE, FALSE));
 160     pa_assert_se(lt_dlmutex_register(libtool_lock, libtool_unlock, libtool_set_error, libtool_get_error) == 0);
 161 #endif
 162
 163 #ifdef PA_BIND_NOW
 164 # ifdef HAVE_STRUCT_LT_USER_DLLOADER
 165
 166     if (!(place = lt_dlloader_find("dlopen")))
 167         place = lt_dlloader_next(NULL);
 168
 169     /* Add our BIND_NOW loader as the default module loader. */
 170     if (lt_dlloader_add(place, &loader, "bind-now-loader") != 0)
 171         pa_log_warn(_("Failed to add bind-now-loader."));
 172 # else
 173     /* Already initialised */
 174     if (dlopen_loader)
 175         return;
 176
 177     if (!(dlopen_loader = lt_dlloader_find("dlopen"))) {
 178         pa_log_warn(_("Failed to find original dlopen loader."));
 179         return;
 180     }
 181
 182     memcpy(&bindnow_loader, dlopen_loader, sizeof(bindnow_loader));
 183     bindnow_loader.name = "bind-now-loader";
 184     bindnow_loader.module_open = bind_now_open;
 185     bindnow_loader.module_close = bind_now_close;
 186     bindnow_loader.find_sym = bind_now_find_sym;
 187     bindnow_loader.priority = LT_DLLOADER_PREPEND;
 188
 189     /* Add our BIND_NOW loader as the default module loader. */
 190     if (lt_dlloader_add(&bindnow_loader) != 0)
 191         pa_log_warn(_("Failed to add bind-now-loader."));
 192 # endif
 193 #endif
 194 }
 195
 196 void pa_ltdl_done(void) {
 197     pa_assert_se(lt_dlexit() == 0);
 198
 199 #ifdef HAVE_LT_DLMUTEX_REGISTER
 200     pa_mutex_free(libtool_mutex);
 201     libtool_mutex = NULL;
 202 #endif
 203 }