root/libltdl/loaders/dld_link.c

/* */

DEFINITIONS

1. get_vtable
2. vl_exit
3. vm_open
4. vm_close
5. vm_sym

   1 /* loader-dld_link.c -- dynamic linking with dld
   2 
   3    Copyright (C) 1998, 1999, 2000, 2004, 2006,
   4                  2007, 2008 Free Software Foundation, Inc.
   5    Written by Thomas Tanner, 1998
   6 
   7    NOTE: The canonical source of this file is maintained with the
   8    GNU Libtool package.  Report bugs to bug-libtool@gnu.org.
   9 
  10 GNU Libltdl is free software; you can redistribute it and/or
  11 modify it under the terms of the GNU Lesser General Public
  12 License as published by the Free Software Foundation; either
  13 version 2 of the License, or (at your option) any later version.
  14 
  15 As a special exception to the GNU Lesser General Public License,
  16 if you distribute this file as part of a program or library that
  17 is built using GNU Libtool, you may include this file under the
  18 same distribution terms that you use for the rest of that program.
  19 
  20 GNU Libltdl is distributed in the hope that it will be useful,
  21 but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23 GNU Lesser General Public License for more details.
  24 
  25 You should have received a copy of the GNU Lesser General Public
  26 License along with GNU Libltdl; see the file COPYING.LIB.  If not, a
  27 copy can be downloaded from  http://www.gnu.org/licenses/lgpl.html,
  28 or obtained by writing to the Free Software Foundation, Inc.,
  29 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  30 */
  31 
  32 #include "lt__private.h"
  33 #include "lt_dlloader.h"
  34 
  35 /* Use the preprocessor to rename non-static symbols to avoid namespace
  36    collisions when the loader code is statically linked into libltdl.
  37    Use the "<module_name>_LTX_" prefix so that the symbol addresses can
  38    be fetched from the preloaded symbol list by lt_dlsym():  */
  39 #define get_vtable      dld_link_LTX_get_vtable
  40 
  41 LT_BEGIN_C_DECLS
  42 LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data);
  43 LT_END_C_DECLS
  44 
  45 
  46 /* Boilerplate code to set up the vtable for hooking this loader into
  47    libltdl's loader list:  */
  48 static int       vl_exit  (lt_user_data loader_data);
  49 static lt_module vm_open  (lt_user_data loader_data, const char *filename,
  50                            lt_dladvise advise);
  51 static int       vm_close (lt_user_data loader_data, lt_module module);
  52 static void *    vm_sym   (lt_user_data loader_data, lt_module module,
  53                           const char *symbolname);
  54 
  55 static lt_dlvtable *vtable = 0;
  56 
  57 /* Return the vtable for this loader, only the name and sym_prefix
  58    attributes (plus the virtual function implementations, obviously)
  59    change between loaders.  */
  60 lt_dlvtable *
  61 get_vtable (lt_user_data loader_data)
  62 {
  63   if (!vtable)
  64     {
  65       vtable = lt__zalloc (sizeof *vtable);
  66     }
  67 
  68   if (vtable && !vtable->name)
  69     {
  70       vtable->name              = "lt_dld_link";
  71       vtable->module_open       = vm_open;
  72       vtable->module_close      = vm_close;
  73       vtable->find_sym          = vm_sym;
  74       vtable->dlloader_exit     = vl_exit;
  75       vtable->dlloader_data     = loader_data;
  76       vtable->priority          = LT_DLLOADER_APPEND;
  77     }
  78 
  79   if (vtable && (vtable->dlloader_data != loader_data))
  80     {
  81       LT__SETERROR (INIT_LOADER);
  82       return 0;
  83     }
  84 
  85   return vtable;
  86 }
  87 
  88 
  89 
  90 /* --- IMPLEMENTATION --- */
  91 
  92 
  93 #if defined(HAVE_DLD_H)
  94 #  include <dld.h>
  95 #endif
  96 
  97 /* A function called through the vtable when this loader is no
  98    longer needed by the application.  */
  99 static int
 100 vl_exit (lt_user_data LT__UNUSED loader_data)
 101 {
 102   vtable = NULL;
 103   return 0;
 104 }
 105 
 106 /* A function called through the vtable to open a module with this
 107    loader.  Returns an opaque representation of the newly opened
 108    module for processing with this loader's other vtable functions.  */
 109 static lt_module
 110 vm_open (lt_user_data LT__UNUSED loader_data, const char *filename,
 111          lt_dladvise LT__UNUSED advise)
 112 {
 113   lt_module module = lt__strdup (filename);
 114 
 115   if (dld_link (filename) != 0)
 116     {
 117       LT__SETERROR (CANNOT_OPEN);
 118       FREE (module);
 119     }
 120 
 121   return module;
 122 }
 123 
 124 /* A function called through the vtable when a particular module
 125    should be unloaded.  */
 126 static int
 127 vm_close (lt_user_data LT__UNUSED loader_data, lt_module module)
 128 {
 129   int errors = 0;
 130 
 131   if (dld_unlink_by_file ((char*)(module), 1) != 0)
 132     {
 133       LT__SETERROR (CANNOT_CLOSE);
 134       ++errors;
 135     }
 136   else
 137     {
 138       FREE (module);
 139     }
 140 
 141   return errors;
 142 }
 143 
 144 /* A function called through the vtable to get the address of
 145    a symbol loaded from a particular module.  */
 146 static void *
 147 vm_sym (lt_user_data LT__UNUSED loader_data, lt_module LT__UNUSED module,
 148         const char *name)
 149 {
 150   void *address = dld_get_func (name);
 151 
 152   if (!address)
 153     {
 154       LT__SETERROR (SYMBOL_NOT_FOUND);
 155     }
 156 
 157   return address;
 158 }

/* */