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b3fc5f84 | 1 | /* Handle loading and unloading shared objects for internal libc purposes. |
22c83193 | 2 | Copyright (C) 1999-2002,2004,2005,2006,2009 Free Software Foundation, Inc. |
b3fc5f84 UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Zack Weinberg <zack@rabi.columbia.edu>, 1999. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
b3fc5f84 UD |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
b3fc5f84 | 15 | |
41bdb6e2 AJ |
16 | You should have received a copy of the GNU Lesser General Public |
17 | License along with the GNU C Library; if not, write to the Free | |
18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
19 | 02111-1307 USA. */ | |
b3fc5f84 UD |
20 | |
21 | #include <dlfcn.h> | |
22 | #include <stdlib.h> | |
23 | #include <ldsodefs.h> | |
24 | ||
9dcafc55 UD |
25 | extern int __libc_argc attribute_hidden; |
26 | extern char **__libc_argv attribute_hidden; | |
27 | ||
28 | extern char **__environ; | |
29 | ||
b3fc5f84 UD |
30 | /* The purpose of this file is to provide wrappers around the dynamic |
31 | linker error mechanism (similar to dlopen() et al in libdl) which | |
32 | are usable from within libc. Generally we want to throw away the | |
33 | string that dlerror() would return and just pass back a null pointer | |
34 | for errors. This also lets the rest of libc not know about the error | |
35 | handling mechanism. | |
36 | ||
37 | Much of this code came from gconv_dl.c with slight modifications. */ | |
38 | ||
39 | static int | |
40 | internal_function | |
41 | dlerror_run (void (*operate) (void *), void *args) | |
42 | { | |
8e17ea58 UD |
43 | const char *objname; |
44 | const char *last_errstring = NULL; | |
74780cf6 | 45 | bool malloced; |
b3fc5f84 | 46 | |
74780cf6 UD |
47 | (void) GLRO(dl_catch_error) (&objname, &last_errstring, &malloced, |
48 | operate, args); | |
b3fc5f84 | 49 | |
74780cf6 UD |
50 | int result = last_errstring != NULL; |
51 | if (result && malloced) | |
8e17ea58 | 52 | free ((char *) last_errstring); |
b3fc5f84 UD |
53 | |
54 | return result; | |
55 | } | |
56 | ||
57 | /* These functions are called by dlerror_run... */ | |
58 | ||
59 | struct do_dlopen_args | |
60 | { | |
61 | /* Argument to do_dlopen. */ | |
62 | const char *name; | |
3c857306 UD |
63 | /* Opening mode. */ |
64 | int mode; | |
b3fc5f84 UD |
65 | |
66 | /* Return from do_dlopen. */ | |
67 | struct link_map *map; | |
68 | }; | |
69 | ||
70 | struct do_dlsym_args | |
71 | { | |
72 | /* Arguments to do_dlsym. */ | |
73 | struct link_map *map; | |
74 | const char *name; | |
75 | ||
76 | /* Return values of do_dlsym. */ | |
c0282c06 | 77 | lookup_t loadbase; |
b3fc5f84 UD |
78 | const ElfW(Sym) *ref; |
79 | }; | |
80 | ||
81 | static void | |
82 | do_dlopen (void *ptr) | |
83 | { | |
84 | struct do_dlopen_args *args = (struct do_dlopen_args *) ptr; | |
85 | /* Open and relocate the shared object. */ | |
9dcafc55 UD |
86 | args->map = GLRO(dl_open) (args->name, args->mode, NULL, __LM_ID_CALLER, |
87 | __libc_argc, __libc_argv, __environ); | |
b3fc5f84 UD |
88 | } |
89 | ||
90 | static void | |
91 | do_dlsym (void *ptr) | |
92 | { | |
93 | struct do_dlsym_args *args = (struct do_dlsym_args *) ptr; | |
94 | args->ref = NULL; | |
021723ab UD |
95 | args->loadbase = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref, |
96 | args->map->l_local_scope, NULL, 0, | |
97 | DL_LOOKUP_RETURN_NEWEST, NULL); | |
b3fc5f84 UD |
98 | } |
99 | ||
100 | static void | |
101 | do_dlclose (void *ptr) | |
102 | { | |
9dcafc55 | 103 | GLRO(dl_close) ((struct link_map *) ptr); |
b3fc5f84 UD |
104 | } |
105 | ||
81b215af UD |
106 | /* This code is to support __libc_dlopen from __libc_dlopen'ed shared |
107 | libraries. We need to ensure the statically linked __libc_dlopen | |
108 | etc. functions are used instead of the dynamically loaded. */ | |
109 | struct dl_open_hook | |
110 | { | |
111 | void *(*dlopen_mode) (const char *name, int mode); | |
112 | void *(*dlsym) (void *map, const char *name); | |
113 | int (*dlclose) (void *map); | |
114 | }; | |
115 | ||
116 | #ifdef SHARED | |
117 | extern struct dl_open_hook *_dl_open_hook; | |
118 | libc_hidden_proto (_dl_open_hook); | |
9dcafc55 | 119 | struct dl_open_hook *_dl_open_hook __attribute__ ((nocommon)); |
81b215af UD |
120 | libc_hidden_data_def (_dl_open_hook); |
121 | #else | |
122 | static void | |
123 | do_dlsym_private (void *ptr) | |
124 | { | |
125 | lookup_t l; | |
126 | struct r_found_version vers; | |
127 | vers.name = "GLIBC_PRIVATE"; | |
128 | vers.hidden = 1; | |
9dcafc55 | 129 | /* vers.hash = _dl_elf_hash (vers.name); */ |
81b215af | 130 | vers.hash = 0x0963cf85; |
81b215af UD |
131 | vers.filename = NULL; |
132 | ||
133 | struct do_dlsym_args *args = (struct do_dlsym_args *) ptr; | |
134 | args->ref = NULL; | |
021723ab | 135 | l = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref, |
c0a777e8 | 136 | args->map->l_scope, &vers, 0, 0, NULL); |
81b215af UD |
137 | args->loadbase = l; |
138 | } | |
139 | ||
140 | static struct dl_open_hook _dl_open_hook = | |
141 | { | |
142 | .dlopen_mode = __libc_dlopen_mode, | |
143 | .dlsym = __libc_dlsym, | |
144 | .dlclose = __libc_dlclose | |
145 | }; | |
146 | #endif | |
147 | ||
b3fc5f84 UD |
148 | /* ... and these functions call dlerror_run. */ |
149 | ||
150 | void * | |
3c857306 | 151 | __libc_dlopen_mode (const char *name, int mode) |
b3fc5f84 UD |
152 | { |
153 | struct do_dlopen_args args; | |
3c857306 UD |
154 | args.name = name; |
155 | args.mode = mode; | |
b3fc5f84 | 156 | |
81b215af UD |
157 | #ifdef SHARED |
158 | if (__builtin_expect (_dl_open_hook != NULL, 0)) | |
159 | return _dl_open_hook->dlopen_mode (name, mode); | |
b3fc5f84 | 160 | return (dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map); |
81b215af UD |
161 | #else |
162 | if (dlerror_run (do_dlopen, &args)) | |
163 | return NULL; | |
164 | ||
790b6c7a UD |
165 | __libc_register_dl_open_hook (args.map); |
166 | __libc_register_dlfcn_hook (args.map); | |
167 | return (void *) args.map; | |
168 | #endif | |
169 | } | |
170 | libc_hidden_def (__libc_dlopen_mode) | |
171 | ||
172 | #ifndef SHARED | |
173 | void * | |
174 | __libc_dlsym_private (struct link_map *map, const char *name) | |
175 | { | |
81b215af | 176 | struct do_dlsym_args sargs; |
790b6c7a UD |
177 | sargs.map = map; |
178 | sargs.name = name; | |
81b215af UD |
179 | |
180 | if (! dlerror_run (do_dlsym_private, &sargs)) | |
790b6c7a UD |
181 | return DL_SYMBOL_ADDRESS (sargs.loadbase, sargs.ref); |
182 | return NULL; | |
183 | } | |
81b215af | 184 | |
790b6c7a UD |
185 | void |
186 | __libc_register_dl_open_hook (struct link_map *map) | |
187 | { | |
188 | struct dl_open_hook **hook; | |
189 | ||
190 | hook = (struct dl_open_hook **) __libc_dlsym_private (map, "_dl_open_hook"); | |
191 | if (hook != NULL) | |
192 | *hook = &_dl_open_hook; | |
b3fc5f84 | 193 | } |
790b6c7a | 194 | #endif |
b3fc5f84 UD |
195 | |
196 | void * | |
3c857306 | 197 | __libc_dlsym (void *map, const char *name) |
b3fc5f84 UD |
198 | { |
199 | struct do_dlsym_args args; | |
3c857306 UD |
200 | args.map = map; |
201 | args.name = name; | |
b3fc5f84 | 202 | |
81b215af UD |
203 | #ifdef SHARED |
204 | if (__builtin_expect (_dl_open_hook != NULL, 0)) | |
205 | return _dl_open_hook->dlsym (map, name); | |
206 | #endif | |
b3fc5f84 | 207 | return (dlerror_run (do_dlsym, &args) ? NULL |
b511d8fc | 208 | : (void *) (DL_SYMBOL_ADDRESS (args.loadbase, args.ref))); |
b3fc5f84 | 209 | } |
9d79e037 | 210 | libc_hidden_def (__libc_dlsym) |
b3fc5f84 UD |
211 | |
212 | int | |
3c857306 | 213 | __libc_dlclose (void *map) |
b3fc5f84 | 214 | { |
81b215af UD |
215 | #ifdef SHARED |
216 | if (__builtin_expect (_dl_open_hook != NULL, 0)) | |
217 | return _dl_open_hook->dlclose (map); | |
218 | #endif | |
3c857306 | 219 | return dlerror_run (do_dlclose, map); |
b3fc5f84 | 220 | } |
9d79e037 | 221 | libc_hidden_def (__libc_dlclose) |
752a2a50 UD |
222 | |
223 | ||
c877418f | 224 | libc_freeres_fn (free_mem) |
752a2a50 UD |
225 | { |
226 | struct link_map *l; | |
f55727ca UD |
227 | struct r_search_path_elem *d; |
228 | ||
229 | /* Remove all search directories. */ | |
d6b5d570 | 230 | d = GL(dl_all_dirs); |
c31e278f | 231 | while (d != GLRO(dl_init_all_dirs)) |
f55727ca UD |
232 | { |
233 | struct r_search_path_elem *old = d; | |
234 | d = d->next; | |
235 | free (old); | |
236 | } | |
752a2a50 UD |
237 | |
238 | /* Remove all additional names added to the objects. */ | |
22c83193 | 239 | for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns) |
c0f62c56 UD |
240 | for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next) |
241 | { | |
242 | struct libname_list *lnp = l->l_libname->next; | |
243 | ||
244 | l->l_libname->next = NULL; | |
245 | ||
246 | while (lnp != NULL) | |
247 | { | |
248 | struct libname_list *old = lnp; | |
249 | lnp = lnp->next; | |
250 | if (! old->dont_free) | |
752a2a50 | 251 | free (old); |
c0f62c56 UD |
252 | } |
253 | } | |
752a2a50 | 254 | } |