libltdl/loaders/shl

/* */
This source file includes following definitions.
get_vtable
vl_exit
vm_open
vm_close
vm_sym
   1 /* loader-shl_load.c --  dynamic linking with shl_load (HP-UX)
   2 
   3    Copyright (C) 1998-2000, 2004, 2006-2008, 2011-2015 Free Software
   4    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      shl_load_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_shl_load";
  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_DL_H
  94 #  include <dl.h>
  95 #endif
  96 
  97 /* some flags are missing on some systems, so we provide
  98  * harmless defaults.
  99  *
 100  * Mandatory:
 101  * BIND_IMMEDIATE  - Resolve symbol references when the library is loaded.
 102  * BIND_DEFERRED   - Delay code symbol resolution until actual reference.
 103  *
 104  * Optionally:
 105  * BIND_FIRST      - Place the library at the head of the symbol search
 106  *                   order.
 107  * BIND_NONFATAL   - The default BIND_IMMEDIATE behavior is to treat all
 108  *                   unsatisfied symbols as fatal.  This flag allows
 109  *                   binding of unsatisfied code symbols to be deferred
 110  *                   until use.
 111  *                   [Perl: For certain libraries, like DCE, deferred
 112  *                   binding often causes run time problems. Adding
 113  *                   BIND_NONFATAL to BIND_IMMEDIATE still allows
 114  *                   unresolved references in situations like this.]
 115  * BIND_NOSTART    - Do not call the initializer for the shared library
 116  *                   when the library is loaded, nor on a future call to
 117  *                   shl_unload().
 118  * BIND_VERBOSE    - Print verbose messages concerning possible
 119  *                   unsatisfied symbols.
 120  *
 121  * hp9000s700/hp9000s800:
 122  * BIND_RESTRICTED - Restrict symbols visible by the library to those
 123  *                   present at library load time.
 124  * DYNAMIC_PATH    - Allow the loader to dynamically search for the
 125  *                   library specified by the path argument.
 126  */
 127 
 128 #if !defined DYNAMIC_PATH
 129 #  define DYNAMIC_PATH          0
 130 #endif
 131 #if !defined BIND_RESTRICTED
 132 #  define BIND_RESTRICTED       0
 133 #endif
 134 
 135 #define LT_BIND_FLAGS   (BIND_IMMEDIATE | BIND_NONFATAL | DYNAMIC_PATH)
 136 
 137 
 138 /* A function called through the vtable when this loader is no
 139    longer needed by the application.  */
 140 static int
 141 vl_exit (lt_user_data loader_data LT__UNUSED)
     /*  */
 142 {
 143   vtable = NULL;
 144   return 0;
 145 }
 146 
 147 /* A function called through the vtable to open a module with this
 148    loader.  Returns an opaque representation of the newly opened
 149    module for processing with this loader's other vtable functions.  */
 150 static lt_module
 151 vm_open (lt_user_data loader_data LT__UNUSED, const char *filename,
     /*  */
 152          lt_dladvise advise LT__UNUSED)
 153 {
 154   static shl_t self = (shl_t) 0;
 155   lt_module module = shl_load (filename, LT_BIND_FLAGS, 0L);
 156 
 157   /* Since searching for a symbol against a NULL module handle will also
 158      look in everything else that was already loaded and exported with
 159      the -E compiler flag, we always cache a handle saved before any
 160      modules are loaded.  */
 161   if (!self)
 162     {
 163       void *address;
 164       shl_findsym (&self, "main", TYPE_UNDEFINED, &address);
 165     }
 166 
 167   if (!filename)
 168     {
 169       module = self;
 170     }
 171   else
 172     {
 173       module = shl_load (filename, LT_BIND_FLAGS, 0L);
 174 
 175       if (!module)
 176         {
 177           LT__SETERROR (CANNOT_OPEN);
 178         }
 179     }
 180 
 181   return module;
 182 }
 183 
 184 /* A function called through the vtable when a particular module
 185    should be unloaded.  */
 186 static int
 187 vm_close (lt_user_data loader_data LT__UNUSED, lt_module module)
     /*  */
 188 {
 189   int errors = 0;
 190 
 191   if (module && (shl_unload ((shl_t) (module)) != 0))
 192     {
 193       LT__SETERROR (CANNOT_CLOSE);
 194       ++errors;
 195     }
 196 
 197   return errors;
 198 }
 199 
 200 
 201 /* A function called through the vtable to get the address of
 202    a symbol loaded from a particular module.  */
 203 static void *
 204 vm_sym (lt_user_data loader_data LT__UNUSED, lt_module module, const char *name)
     /*  */
 205 {
 206   void *address = 0;
 207 
 208   /* sys_shl_open should never return a NULL module handle */
 209   if (module == (lt_module) 0)
 210   {
 211     LT__SETERROR (INVALID_HANDLE);
 212   }
 213   else if (!shl_findsym((shl_t*) &module, name, TYPE_UNDEFINED, &address))
 214     {
 215       if (!address)
 216         {
 217           LT__SETERROR (SYMBOL_NOT_FOUND);
 218         }
 219     }
 220 
 221   return address;
 222 }
/* */
root/libltdl/loaders/shl_load.c

DEFINITIONS
