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

Last change on this file since 5496 was 5496, checked in by Juanma, 22 months ago

Initial release

File size: 6.6 KB
Line 
1/* loader-shl_load.c --  dynamic linking with shl_load (HP-UX)
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      shl_load_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_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.  */
140static int
141vl_exit (lt_user_data LT__UNUSED loader_data)
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.  */
150static lt_module
151vm_open (lt_user_data LT__UNUSED loader_data, const char *filename,
152         lt_dladvise LT__UNUSED advise)
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.  */
186static int
187vm_close (lt_user_data LT__UNUSED loader_data, 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.  */
203static void *
204vm_sym (lt_user_data LT__UNUSED loader_data, 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}
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