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 PA_BIND_NOW
  57
  58 /*
  59   To avoid lazy relocations during runtime in our RT threads we add
  60   our own shared object loader with uses RTLD_NOW if it is
  61   available. The standard ltdl loader prefers RTLD_LAZY.
  62
  63   Please note that this loader doesn't have any influence on
  64   relocations on any libraries that are already loaded into our
  65   process, i.e. because the pulseaudio binary links directly to
  66   them. To disable lazy relocations for those libraries it is possible
  67   to set $LT_BIND_NOW before starting the pulsaudio binary.
  68 */
  69
  70 static lt_module bind_now_open(lt_user_data d, const char *fname, lt_dladvise advise)
  71 {
  72     lt_module m;
  73
  74     pa_assert(fname);
  75
  76     if (!(m = dlopen(fname, PA_BIND_NOW))) {
  77         libtool_set_error(dlerror());
  78         return NULL;
  79     }
  80
  81     return m;
  82 }
  83
  84 static int bind_now_close(lt_user_data d, lt_module m) {
  85
  86     pa_assert(m);
  87
  88     if (dlclose(m) != 0){
  89         libtool_set_error(dlerror());
  90         return 1;
  91     }
  92
  93     return 0;
  94 }
  95
  96 static lt_ptr bind_now_find_sym(lt_user_data d, lt_module m, const char *symbol) {
  97     lt_ptr ptr;
  98
  99     pa_assert(m);
 100     pa_assert(symbol);
 101
 102     if (!(ptr = dlsym(m, symbol))) {
 103         libtool_set_error(dlerror());
 104         return NULL;
 105     }
 106
 107     return ptr;
 108 }
 109
 110 #endif
 111
 112 void pa_ltdl_init(void) {
 113
 114 #ifdef PA_BIND_NOW
 115     static const lt_dlvtable *dlopen_loader;
 116     static lt_dlvtable bindnow_loader;
 117 #endif
 118
 119     pa_assert_se(lt_dlinit() == 0);
 120
 121 #ifdef PA_BIND_NOW
 122     /* Already initialised */
 123     if (dlopen_loader)
 124         return;
 125
 126     if (!(dlopen_loader = lt_dlloader_find("dlopen"))) {
 127         pa_log_warn(_("Failed to find original dlopen loader."));
 128         return;
 129     }
 130
 131     memcpy(&bindnow_loader, dlopen_loader, sizeof(bindnow_loader));
 132     bindnow_loader.name = "bind-now-loader";
 133     bindnow_loader.module_open = bind_now_open;
 134     bindnow_loader.module_close = bind_now_close;
 135     bindnow_loader.find_sym = bind_now_find_sym;
 136     bindnow_loader.priority = LT_DLLOADER_PREPEND;
 137
 138     /* Add our BIND_NOW loader as the default module loader. */
 139     if (lt_dlloader_add(&bindnow_loader) != 0)
 140         pa_log_warn(_("Failed to add bind-now-loader."));
 141 #endif
 142 }
 143
 144 void pa_ltdl_done(void) {
 145     pa_assert_se(lt_dlexit() == 0);
 146 }