/[svn]/ircd-hybrid-7.2/libltdl/loaders/dlopen.c
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Contents of /ircd-hybrid-7.2/libltdl/loaders/dlopen.c

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Revision 945 - (show annotations)
Mon Jul 20 15:48:27 2009 UTC (10 years, 11 months ago) by michael
File MIME type: text/x-chdr
File size: 6369 byte(s)
- fixed some configure mess and imported latest libtool sources

1 /* loader-dlopen.c -- dynamic linking with dlopen/dlsym
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 dlopen_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_dlvtable *) lt__zalloc (sizeof *vtable);
66 }
67
68 if (vtable && !vtable->name)
69 {
70 vtable->name = "lt_dlopen";
71 #if defined(DLSYM_USCORE)
72 vtable->sym_prefix = "_";
73 #endif
74 vtable->module_open = vm_open;
75 vtable->module_close = vm_close;
76 vtable->find_sym = vm_sym;
77 vtable->dlloader_exit = vl_exit;
78 vtable->dlloader_data = loader_data;
79 vtable->priority = LT_DLLOADER_PREPEND;
80 }
81
82 if (vtable && (vtable->dlloader_data != loader_data))
83 {
84 LT__SETERROR (INIT_LOADER);
85 return 0;
86 }
87
88 return vtable;
89 }
90
91
92
93 /* --- IMPLEMENTATION --- */
94
95
96 #if defined(HAVE_DLFCN_H)
97 # include <dlfcn.h>
98 #endif
99
100 #if defined(HAVE_SYS_DL_H)
101 # include <sys/dl.h>
102 #endif
103
104
105 /* We may have to define LT_LAZY_OR_NOW in the command line if we
106 find out it does not work in some platform. */
107 #if !defined(LT_LAZY_OR_NOW)
108 # if defined(RTLD_LAZY)
109 # define LT_LAZY_OR_NOW RTLD_LAZY
110 # else
111 # if defined(DL_LAZY)
112 # define LT_LAZY_OR_NOW DL_LAZY
113 # endif
114 # endif /* !RTLD_LAZY */
115 #endif
116 #if !defined(LT_LAZY_OR_NOW)
117 # if defined(RTLD_NOW)
118 # define LT_LAZY_OR_NOW RTLD_NOW
119 # else
120 # if defined(DL_NOW)
121 # define LT_LAZY_OR_NOW DL_NOW
122 # endif
123 # endif /* !RTLD_NOW */
124 #endif
125 #if !defined(LT_LAZY_OR_NOW)
126 # define LT_LAZY_OR_NOW 0
127 #endif /* !LT_LAZY_OR_NOW */
128
129 /* We only support local and global symbols from modules for loaders
130 that provide such a thing, otherwise the system default is used. */
131 #if !defined(RTLD_GLOBAL)
132 # if defined(DL_GLOBAL)
133 # define RTLD_GLOBAL DL_GLOBAL
134 # endif
135 #endif /* !RTLD_GLOBAL */
136 #if !defined(RTLD_LOCAL)
137 # if defined(DL_LOCAL)
138 # define RTLD_LOCAL DL_LOCAL
139 # endif
140 #endif /* !RTLD_LOCAL */
141
142 #if defined(HAVE_DLERROR)
143 # define DLERROR(arg) dlerror ()
144 #else
145 # define DLERROR(arg) LT__STRERROR (arg)
146 #endif
147
148 #define DL__SETERROR(errorcode) \
149 LT__SETERRORSTR (DLERROR (errorcode))
150
151
152 /* A function called through the vtable when this loader is no
153 longer needed by the application. */
154 static int
155 vl_exit (lt_user_data LT__UNUSED loader_data)
156 {
157 vtable = NULL;
158 return 0;
159 }
160
161
162 /* A function called through the vtable to open a module with this
163 loader. Returns an opaque representation of the newly opened
164 module for processing with this loader's other vtable functions. */
165 static lt_module
166 vm_open (lt_user_data LT__UNUSED loader_data, const char *filename,
167 lt_dladvise advise)
168 {
169 int module_flags = LT_LAZY_OR_NOW;
170 lt_module module;
171
172 if (advise)
173 {
174 #ifdef RTLD_GLOBAL
175 /* If there is some means of asking for global symbol resolution,
176 do so. */
177 if (advise->is_symglobal)
178 module_flags |= RTLD_GLOBAL;
179 #else
180 /* Otherwise, reset that bit so the caller can tell it wasn't
181 acted on. */
182 advise->is_symglobal = 0;
183 #endif
184
185 /* And similarly for local only symbol resolution. */
186 #ifdef RTLD_LOCAL
187 if (advise->is_symlocal)
188 module_flags |= RTLD_LOCAL;
189 #else
190 advise->is_symlocal = 0;
191 #endif
192 }
193
194 module = dlopen (filename, module_flags);
195
196 if (!module)
197 {
198 DL__SETERROR (CANNOT_OPEN);
199 }
200
201 return module;
202 }
203
204
205 /* A function called through the vtable when a particular module
206 should be unloaded. */
207 static int
208 vm_close (lt_user_data LT__UNUSED loader_data, lt_module module)
209 {
210 int errors = 0;
211
212 if (dlclose (module) != 0)
213 {
214 DL__SETERROR (CANNOT_CLOSE);
215 ++errors;
216 }
217
218 return errors;
219 }
220
221
222 /* A function called through the vtable to get the address of
223 a symbol loaded from a particular module. */
224 static void *
225 vm_sym (lt_user_data LT__UNUSED loader_data, lt_module module, const char *name)
226 {
227 void *address = dlsym (module, name);
228
229 if (!address)
230 {
231 DL__SETERROR (SYMBOL_NOT_FOUND);
232 }
233
234 return address;
235 }

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