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