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 #ifndef HAVE_STRUCT_LT_USER_DLLOADER
  38 /* Only used with ltdl 2.2 */
  39 #include <string.h>
  40 #endif
  41
  42 #include <ltdl.h>
  43
  44 #include <pulsecore/macro.h>
  45 #include <pulsecore/mutex.h>
  46 #include <pulsecore/thread.h>
  47 #include <pulsecore/log.h>
  48
  49 #include "ltdl-bind-now.h"
  50
  51 #ifdef RTLD_NOW
  52 #define PA_BIND_NOW RTLD_NOW
  53 #elif defined(DL_NOW)
  54 #define PA_BIND_NOW DL_NOW
  55 #else
  56 #undef PA_BIND_NOW
  57 #endif
  58
  59 static pa_mutex *libtool_mutex = NULL;
  60
  61 PA_STATIC_TLS_DECLARE_NO_FREE(libtool_tls);
  62
  63 static void libtool_lock(void) {
  64     pa_mutex_lock(libtool_mutex);
  65 }
  66
  67 static void libtool_unlock(void) {
  68     pa_mutex_unlock(libtool_mutex);
  69 }
  70
  71 static void libtool_set_error(const char *error) {
  72     PA_STATIC_TLS_SET(libtool_tls, (char*) error);
  73 }
  74
  75 static const char *libtool_get_error(void) {
  76     return PA_STATIC_TLS_GET(libtool_tls);
  77 }
  78
  79 #ifdef PA_BIND_NOW
  80
  81 /*
  82   To avoid lazy relocations during runtime in our RT threads we add
  83   our own shared object loader with uses RTLD_NOW if it is
  84   available. The standard ltdl loader prefers RTLD_LAZY.
  85
  86   Please note that this loader doesn't have any influence on
  87   relocations on any libraries that are already loaded into our
  88   process, i.e. because the pulseaudio binary links directly to
  89   them. To disable lazy relocations for those libraries it is possible
  90   to set $LT_BIND_NOW before starting the pulsaudio binary.
  91 */
  92
  93 #ifndef HAVE_LT_DLADVISE
  94 static lt_module bind_now_open(lt_user_data d, const char *fname) {
  95 #else
  96   static lt_module bind_now_open(lt_user_data d, const char *fname, lt_dladvise advise) {
  97 #endif
  98     lt_module m;
  99
 100     pa_assert(fname);
 101
 102     if (!(m = dlopen(fname, PA_BIND_NOW))) {
 103         libtool_set_error(dlerror());
 104         return NULL;
 105     }
 106
 107     return m;
 108 }
 109
 110 static int bind_now_close(lt_user_data d, lt_module m) {
 111
 112     pa_assert(m);
 113
 114     if (dlclose(m) != 0){
 115         libtool_set_error(dlerror());
 116         return 1;
 117     }
 118
 119     return 0;
 120 }
 121
 122 static lt_ptr bind_now_find_sym(lt_user_data d, lt_module m, const char *symbol) {
 123     lt_ptr ptr;
 124
 125     pa_assert(m);
 126     pa_assert(symbol);
 127
 128     if (!(ptr = dlsym(m, symbol))) {
 129         libtool_set_error(dlerror());
 130         return NULL;
 131     }
 132
 133     return ptr;
 134 }
 135
 136 #endif
 137
 138 void pa_ltdl_init(void) {
 139
 140 #ifdef PA_BIND_NOW
 141 # ifdef HAVE_STRUCT_LT_USER_DLLOADER
 142     lt_dlloader *place;
 143     static const struct lt_user_dlloader loader = {
 144         .module_open = bind_now_open,
 145         .module_close = bind_now_close,
 146         .find_sym = bind_now_find_sym
 147     };
 148 # else
 149     static const lt_dlvtable *dlopen_loader;
 150     static lt_dlvtable bindnow_loader;
 151 # endif
 152 #endif
 153
 154     pa_assert_se(lt_dlinit() == 0);
 155     pa_assert_se(libtool_mutex = pa_mutex_new(TRUE, FALSE));
 156 #ifdef HAVE_LT_DLMUTEX_REGISTER
 157     pa_assert_se(lt_dlmutex_register(libtool_lock, libtool_unlock, libtool_set_error, libtool_get_error) == 0);
 158 #endif
 159
 160 #ifdef PA_BIND_NOW
 161 # ifdef HAVE_STRUCT_LT_USER_DLLOADER
 162
 163     if (!(place = lt_dlloader_find("dlopen")))
 164         place = lt_dlloader_next(NULL);
 165
 166     /* Add our BIND_NOW loader as the default module loader. */
 167     if (lt_dlloader_add(place, &loader, "bind-now-loader") != 0)
 168         pa_log_warn("Failed to add bind-now-loader.");
 169 # else
 170     /* Already initialised */
 171     if ( dlopen_loader != NULL ) return;
 172
 173     if (!(dlopen_loader = lt_dlloader_find("dlopen"))) {
 174       pa_log_warn("Failed to find original dlopen loader.");
 175       return;
 176     }
 177
 178     memcpy(&bindnow_loader, dlopen_loader, sizeof(bindnow_loader));
 179     bindnow_loader.name = "bind-now-loader";
 180     bindnow_loader.module_open = bind_now_open;
 181     bindnow_loader.module_close = bind_now_close;
 182     bindnow_loader.find_sym = bind_now_find_sym;
 183     bindnow_loader.priority = LT_DLLOADER_PREPEND;
 184
 185     /* Add our BIND_NOW loader as the default module loader. */
 186     if (lt_dlloader_add(&bindnow_loader) != 0)
 187         pa_log_warn("Failed to add bind-now-loader.");
 188 # endif
 189 #endif
 190 }
 191
 192 void pa_ltdl_done(void) {
 193     pa_assert_se(lt_dlexit() == 0);
 194     pa_mutex_free(libtool_mutex);
 195     libtool_mutex = NULL;
 196 }
 197