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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, 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 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 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. */
150 static lt_module
151 vm_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. */
186 static int
187 vm_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. */
203 static void *
204 vm_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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