source: squid-ssl/trunk/fuentes/libltdl/loaders/dld_link.c @ 5496

Last change on this file since 5496 was 5496, checked in by Juanma, 23 months ago

Initial release

File size: 4.5 KB
Line 
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
10GNU Libltdl is free software; you can redistribute it and/or
11modify it under the terms of the GNU Lesser General Public
12License as published by the Free Software Foundation; either
13version 2 of the License, or (at your option) any later version.
14
15As a special exception to the GNU Lesser General Public License,
16if you distribute this file as part of a program or library that
17is built using GNU Libtool, you may include this file under the
18same distribution terms that you use for the rest of that program.
19
20GNU Libltdl is distributed in the hope that it will be useful,
21but WITHOUT ANY WARRANTY; without even the implied warranty of
22MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
23GNU Lesser General Public License for more details.
24
25You should have received a copy of the GNU Lesser General Public
26License along with GNU Libltdl; see the file COPYING.LIB.  If not, a
27copy can be downloaded from  http://www.gnu.org/licenses/lgpl.html,
28or obtained by writing to the Free Software Foundation, Inc.,
2951 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
41LT_BEGIN_C_DECLS
42LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data);
43LT_END_C_DECLS
44
45
46/* Boilerplate code to set up the vtable for hooking this loader into
47   libltdl's loader list:  */
48static int       vl_exit  (lt_user_data loader_data);
49static lt_module vm_open  (lt_user_data loader_data, const char *filename,
50                           lt_dladvise advise);
51static int       vm_close (lt_user_data loader_data, lt_module module);
52static void *    vm_sym   (lt_user_data loader_data, lt_module module,
53                          const char *symbolname);
54
55static 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.  */
60lt_dlvtable *
61get_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.  */
99static int
100vl_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.  */
109static lt_module
110vm_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.  */
126static int
127vm_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.  */
146static void *
147vm_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}
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