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b3fc5f84 | 1 | /* Handle loading and unloading shared objects for internal libc purposes. |
688903eb | 2 | Copyright (C) 1999-2018 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 | 16 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
b3fc5f84 UD |
19 | |
20 | #include <dlfcn.h> | |
21 | #include <stdlib.h> | |
22 | #include <ldsodefs.h> | |
23 | ||
9dcafc55 UD |
24 | extern int __libc_argc attribute_hidden; |
25 | extern char **__libc_argv attribute_hidden; | |
26 | ||
27 | extern char **__environ; | |
28 | ||
b3fc5f84 UD |
29 | /* The purpose of this file is to provide wrappers around the dynamic |
30 | linker error mechanism (similar to dlopen() et al in libdl) which | |
31 | are usable from within libc. Generally we want to throw away the | |
32 | string that dlerror() would return and just pass back a null pointer | |
33 | for errors. This also lets the rest of libc not know about the error | |
34 | handling mechanism. | |
35 | ||
36 | Much of this code came from gconv_dl.c with slight modifications. */ | |
37 | ||
38 | static int | |
b3fc5f84 UD |
39 | dlerror_run (void (*operate) (void *), void *args) |
40 | { | |
8e17ea58 UD |
41 | const char *objname; |
42 | const char *last_errstring = NULL; | |
74780cf6 | 43 | bool malloced; |
b3fc5f84 | 44 | |
9e78f6f6 FW |
45 | int result = (_dl_catch_error (&objname, &last_errstring, &malloced, |
46 | operate, args) | |
fdc86bc9 | 47 | ?: last_errstring != NULL); |
b3fc5f84 | 48 | |
74780cf6 | 49 | if (result && malloced) |
8e17ea58 | 50 | free ((char *) last_errstring); |
b3fc5f84 UD |
51 | |
52 | return result; | |
53 | } | |
54 | ||
55 | /* These functions are called by dlerror_run... */ | |
56 | ||
57 | struct do_dlopen_args | |
58 | { | |
59 | /* Argument to do_dlopen. */ | |
60 | const char *name; | |
3c857306 UD |
61 | /* Opening mode. */ |
62 | int mode; | |
1dc27704 UD |
63 | /* This is the caller of the dlopen() function. */ |
64 | const void *caller_dlopen; | |
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. */ | |
1dc27704 UD |
86 | args->map = GLRO(dl_open) (args->name, args->mode, args->caller_dlopen, |
87 | __LM_ID_CALLER, __libc_argc, __libc_argv, | |
88 | __environ); | |
b3fc5f84 UD |
89 | } |
90 | ||
91 | static void | |
92 | do_dlsym (void *ptr) | |
93 | { | |
94 | struct do_dlsym_args *args = (struct do_dlsym_args *) ptr; | |
95 | args->ref = NULL; | |
021723ab UD |
96 | args->loadbase = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref, |
97 | args->map->l_local_scope, NULL, 0, | |
98 | DL_LOOKUP_RETURN_NEWEST, NULL); | |
b3fc5f84 UD |
99 | } |
100 | ||
101 | static void | |
102 | do_dlclose (void *ptr) | |
103 | { | |
9dcafc55 | 104 | GLRO(dl_close) ((struct link_map *) ptr); |
b3fc5f84 UD |
105 | } |
106 | ||
81b215af UD |
107 | /* This code is to support __libc_dlopen from __libc_dlopen'ed shared |
108 | libraries. We need to ensure the statically linked __libc_dlopen | |
109 | etc. functions are used instead of the dynamically loaded. */ | |
110 | struct dl_open_hook | |
111 | { | |
112 | void *(*dlopen_mode) (const char *name, int mode); | |
113 | void *(*dlsym) (void *map, const char *name); | |
114 | int (*dlclose) (void *map); | |
115 | }; | |
116 | ||
117 | #ifdef SHARED | |
118 | extern struct dl_open_hook *_dl_open_hook; | |
119 | libc_hidden_proto (_dl_open_hook); | |
9dcafc55 | 120 | struct dl_open_hook *_dl_open_hook __attribute__ ((nocommon)); |
81b215af UD |
121 | libc_hidden_data_def (_dl_open_hook); |
122 | #else | |
123 | static void | |
124 | do_dlsym_private (void *ptr) | |
125 | { | |
126 | lookup_t l; | |
127 | struct r_found_version vers; | |
128 | vers.name = "GLIBC_PRIVATE"; | |
129 | vers.hidden = 1; | |
9dcafc55 | 130 | /* vers.hash = _dl_elf_hash (vers.name); */ |
81b215af | 131 | vers.hash = 0x0963cf85; |
81b215af UD |
132 | vers.filename = NULL; |
133 | ||
134 | struct do_dlsym_args *args = (struct do_dlsym_args *) ptr; | |
135 | args->ref = NULL; | |
021723ab | 136 | l = GLRO(dl_lookup_symbol_x) (args->name, args->map, &args->ref, |
c0a777e8 | 137 | args->map->l_scope, &vers, 0, 0, NULL); |
81b215af UD |
138 | args->loadbase = l; |
139 | } | |
140 | ||
141 | static struct dl_open_hook _dl_open_hook = | |
142 | { | |
143 | .dlopen_mode = __libc_dlopen_mode, | |
144 | .dlsym = __libc_dlsym, | |
145 | .dlclose = __libc_dlclose | |
146 | }; | |
147 | #endif | |
148 | ||
b3fc5f84 UD |
149 | /* ... and these functions call dlerror_run. */ |
150 | ||
151 | void * | |
3c857306 | 152 | __libc_dlopen_mode (const char *name, int mode) |
b3fc5f84 UD |
153 | { |
154 | struct do_dlopen_args args; | |
3c857306 UD |
155 | args.name = name; |
156 | args.mode = mode; | |
1dc27704 | 157 | args.caller_dlopen = RETURN_ADDRESS (0); |
b3fc5f84 | 158 | |
81b215af | 159 | #ifdef SHARED |
8e1472d2 | 160 | if (!rtld_active ()) |
81b215af | 161 | return _dl_open_hook->dlopen_mode (name, mode); |
b3fc5f84 | 162 | return (dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map); |
81b215af UD |
163 | #else |
164 | if (dlerror_run (do_dlopen, &args)) | |
165 | return NULL; | |
166 | ||
790b6c7a UD |
167 | __libc_register_dl_open_hook (args.map); |
168 | __libc_register_dlfcn_hook (args.map); | |
169 | return (void *) args.map; | |
170 | #endif | |
171 | } | |
172 | libc_hidden_def (__libc_dlopen_mode) | |
173 | ||
174 | #ifndef SHARED | |
175 | void * | |
176 | __libc_dlsym_private (struct link_map *map, const char *name) | |
177 | { | |
81b215af | 178 | struct do_dlsym_args sargs; |
790b6c7a UD |
179 | sargs.map = map; |
180 | sargs.name = name; | |
81b215af UD |
181 | |
182 | if (! dlerror_run (do_dlsym_private, &sargs)) | |
790b6c7a UD |
183 | return DL_SYMBOL_ADDRESS (sargs.loadbase, sargs.ref); |
184 | return NULL; | |
185 | } | |
81b215af | 186 | |
790b6c7a UD |
187 | void |
188 | __libc_register_dl_open_hook (struct link_map *map) | |
189 | { | |
190 | struct dl_open_hook **hook; | |
191 | ||
192 | hook = (struct dl_open_hook **) __libc_dlsym_private (map, "_dl_open_hook"); | |
193 | if (hook != NULL) | |
194 | *hook = &_dl_open_hook; | |
b3fc5f84 | 195 | } |
790b6c7a | 196 | #endif |
b3fc5f84 UD |
197 | |
198 | void * | |
3c857306 | 199 | __libc_dlsym (void *map, const char *name) |
b3fc5f84 UD |
200 | { |
201 | struct do_dlsym_args args; | |
3c857306 UD |
202 | args.map = map; |
203 | args.name = name; | |
b3fc5f84 | 204 | |
81b215af | 205 | #ifdef SHARED |
8e1472d2 | 206 | if (!rtld_active ()) |
81b215af UD |
207 | return _dl_open_hook->dlsym (map, name); |
208 | #endif | |
b3fc5f84 | 209 | return (dlerror_run (do_dlsym, &args) ? NULL |
b511d8fc | 210 | : (void *) (DL_SYMBOL_ADDRESS (args.loadbase, args.ref))); |
b3fc5f84 | 211 | } |
9d79e037 | 212 | libc_hidden_def (__libc_dlsym) |
b3fc5f84 UD |
213 | |
214 | int | |
3c857306 | 215 | __libc_dlclose (void *map) |
b3fc5f84 | 216 | { |
81b215af | 217 | #ifdef SHARED |
8e1472d2 | 218 | if (!rtld_active ()) |
81b215af UD |
219 | return _dl_open_hook->dlclose (map); |
220 | #endif | |
3c857306 | 221 | return dlerror_run (do_dlclose, map); |
b3fc5f84 | 222 | } |
9d79e037 | 223 | libc_hidden_def (__libc_dlclose) |
752a2a50 UD |
224 | |
225 | ||
56801c50 AS |
226 | static bool __libc_freeres_fn_section |
227 | free_slotinfo (struct dtv_slotinfo_list **elemp) | |
228 | { | |
229 | size_t cnt; | |
230 | ||
231 | if (*elemp == NULL) | |
232 | /* Nothing here, all is removed (or there never was anything). */ | |
233 | return true; | |
234 | ||
235 | if (!free_slotinfo (&(*elemp)->next)) | |
236 | /* We cannot free the entry. */ | |
237 | return false; | |
238 | ||
239 | /* That cleared our next pointer for us. */ | |
240 | ||
241 | for (cnt = 0; cnt < (*elemp)->len; ++cnt) | |
242 | if ((*elemp)->slotinfo[cnt].map != NULL) | |
243 | /* Still used. */ | |
244 | return false; | |
245 | ||
246 | /* We can remove the list element. */ | |
247 | free (*elemp); | |
248 | *elemp = NULL; | |
249 | ||
250 | return true; | |
251 | } | |
252 | ||
253 | ||
c877418f | 254 | libc_freeres_fn (free_mem) |
752a2a50 UD |
255 | { |
256 | struct link_map *l; | |
f55727ca UD |
257 | struct r_search_path_elem *d; |
258 | ||
259 | /* Remove all search directories. */ | |
d6b5d570 | 260 | d = GL(dl_all_dirs); |
c31e278f | 261 | while (d != GLRO(dl_init_all_dirs)) |
f55727ca UD |
262 | { |
263 | struct r_search_path_elem *old = d; | |
264 | d = d->next; | |
265 | free (old); | |
266 | } | |
752a2a50 | 267 | |
22c83193 | 268 | for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns) |
56801c50 | 269 | { |
56801c50 AS |
270 | for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next) |
271 | { | |
272 | struct libname_list *lnp = l->l_libname->next; | |
273 | ||
274 | l->l_libname->next = NULL; | |
275 | ||
0479b305 | 276 | /* Remove all additional names added to the objects. */ |
56801c50 AS |
277 | while (lnp != NULL) |
278 | { | |
279 | struct libname_list *old = lnp; | |
280 | lnp = lnp->next; | |
281 | if (! old->dont_free) | |
282 | free (old); | |
283 | } | |
0479b305 AS |
284 | |
285 | /* Free the initfini dependency list. */ | |
286 | if (l->l_free_initfini) | |
287 | free (l->l_initfini); | |
4b1a6d8b | 288 | l->l_initfini = NULL; |
56801c50 AS |
289 | } |
290 | ||
291 | if (__builtin_expect (GL(dl_ns)[ns]._ns_global_scope_alloc, 0) != 0 | |
292 | && (GL(dl_ns)[ns]._ns_main_searchlist->r_nlist | |
293 | // XXX Check whether we need NS-specific initial_searchlist | |
294 | == GLRO(dl_initial_searchlist).r_nlist)) | |
295 | { | |
296 | /* All object dynamically loaded by the program are unloaded. Free | |
297 | the memory allocated for the global scope variable. */ | |
298 | struct link_map **old = GL(dl_ns)[ns]._ns_main_searchlist->r_list; | |
299 | ||
300 | /* Put the old map in. */ | |
301 | GL(dl_ns)[ns]._ns_main_searchlist->r_list | |
302 | // XXX Check whether we need NS-specific initial_searchlist | |
303 | = GLRO(dl_initial_searchlist).r_list; | |
304 | /* Signal that the original map is used. */ | |
305 | GL(dl_ns)[ns]._ns_global_scope_alloc = 0; | |
306 | ||
307 | /* Now free the old map. */ | |
308 | free (old); | |
09fad1a6 | 309 | } |
56801c50 AS |
310 | } |
311 | ||
d063d164 UD |
312 | /* Free the memory allocated for the dtv slotinfo array. We can do |
313 | this only if all modules which used this memory are unloaded. */ | |
56801c50 | 314 | #ifdef SHARED |
d063d164 UD |
315 | if (GL(dl_initial_dtv) == NULL) |
316 | /* There was no initial TLS setup, it was set up later when | |
317 | it used the normal malloc. */ | |
318 | free_slotinfo (&GL(dl_tls_dtv_slotinfo_list)); | |
319 | else | |
56801c50 | 320 | #endif |
d063d164 UD |
321 | /* The first element of the list does not have to be deallocated. |
322 | It was allocated in the dynamic linker (i.e., with a different | |
323 | malloc), and in the static library it's in .bss space. */ | |
324 | free_slotinfo (&GL(dl_tls_dtv_slotinfo_list)->next); | |
56801c50 AS |
325 | |
326 | void *scope_free_list = GL(dl_scope_free_list); | |
327 | GL(dl_scope_free_list) = NULL; | |
328 | free (scope_free_list); | |
752a2a50 | 329 | } |