rtld: Implement ELF filters (DT_FILTER and DT_AUXILIARY)
[dragonfly.git] / libexec / rtld-elf / x86_64 / reloc.c
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1/*-
2 * Copyright 1996, 1997, 1998, 1999 John D. Polstra.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
f4f4bfd5 25 * $FreeBSD$
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26 */
27
28/*
29 * Dynamic linker for ELF.
30 *
31 * John Polstra <jdp@polstra.com>.
32 */
33
34#include <sys/param.h>
35#include <sys/mman.h>
36#include <sys/tls.h>
37
38#include <machine/sysarch.h>
39#include <machine/tls.h>
40
41#include <dlfcn.h>
42#include <err.h>
43#include <errno.h>
44#include <fcntl.h>
45#include <stdarg.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include <string.h>
49#include <unistd.h>
50
51#include "debug.h"
52#include "rtld.h"
53
54/*
55 * Process the special R_X86_64_COPY relocations in the main program. These
56 * copy data from a shared object into a region in the main program's BSS
57 * segment.
58 *
59 * Returns 0 on success, -1 on failure.
60 */
61int
62do_copy_relocations(Obj_Entry *dstobj)
63{
64 const Elf_Rela *relalim;
65 const Elf_Rela *rela;
66
67 assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */
68
69 relalim = (const Elf_Rela *) ((caddr_t) dstobj->rela + dstobj->relasize);
70 for (rela = dstobj->rela; rela < relalim; rela++) {
71 if (ELF_R_TYPE(rela->r_info) == R_X86_64_COPY) {
72 void *dstaddr;
73 const Elf_Sym *dstsym;
74 const char *name;
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75 size_t size;
76 const void *srcaddr;
77 const Elf_Sym *srcsym;
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78 const Obj_Entry *srcobj, *defobj;
79 SymLook req;
80 int res;
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81
82 dstaddr = (void *) (dstobj->relocbase + rela->r_offset);
83 dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
84 name = dstobj->strtab + dstsym->st_name;
f66e9c25 85 size = dstsym->st_size;
35b2b265
JM
86 symlook_init(&req, name);
87 req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info));
88
89 for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next) {
90 res = symlook_obj(&req, srcobj);
91 if (res == 0) {
92 srcsym = req.sym_out;
93 defobj = req.defobj_out;
f66e9c25 94 break;
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95 }
96 }
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97
98 if (srcobj == NULL) {
99 _rtld_error("Undefined symbol \"%s\" referenced from COPY"
100 " relocation in %s", name, dstobj->path);
101 return -1;
102 }
103
35b2b265 104 srcaddr = (const void *) (defobj->relocbase + srcsym->st_value);
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105 memcpy(dstaddr, srcaddr, size);
106 }
107 }
108
109 return 0;
110}
111
112/* Initialize the special GOT entries. */
113void
114init_pltgot(Obj_Entry *obj)
115{
116 if (obj->pltgot != NULL) {
117 obj->pltgot[1] = (Elf_Addr) obj;
118 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
119 }
120}
121
122/* Process the non-PLT relocations. */
123int
35b2b265 124reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, RtldLockState *lockstate)
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125{
126 const Elf_Rela *relalim;
127 const Elf_Rela *rela;
128 SymCache *cache;
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129 int r = -1;
130
131 /*
132 * The dynamic loader may be called from a thread, we have
133 * limited amounts of stack available so we cannot use alloca().
134 */
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135 if (obj != obj_rtld) {
136 cache = calloc(obj->nchains, sizeof(SymCache));
137 /* No need to check for NULL here */
138 } else
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139 cache = NULL;
140
141 relalim = (const Elf_Rela *) ((caddr_t) obj->rela + obj->relasize);
142 for (rela = obj->rela; rela < relalim; rela++) {
143 Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
144 Elf32_Addr *where32 = (Elf32_Addr *)where;
145
146 switch (ELF_R_TYPE(rela->r_info)) {
147
148 case R_X86_64_NONE:
149 break;
150
151 case R_X86_64_64:
152 {
153 const Elf_Sym *def;
154 const Obj_Entry *defobj;
155
156 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
35b2b265 157 false, cache, lockstate);
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158 if (def == NULL)
159 goto done;
160
161 *where = (Elf_Addr) (defobj->relocbase + def->st_value + rela->r_addend);
162 }
163 break;
164
165 case R_X86_64_PC32:
166 /*
167 * I don't think the dynamic linker should ever see this
168 * type of relocation. But the binutils-2.6 tools sometimes
169 * generate it.
170 */
171 {
172 const Elf_Sym *def;
173 const Obj_Entry *defobj;
174
175 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
35b2b265 176 false, cache, lockstate);
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177 if (def == NULL)
178 goto done;
179
180 *where32 = (Elf32_Addr) (unsigned long) (defobj->relocbase +
181 def->st_value + rela->r_addend - (Elf_Addr) where);
182 }
183 break;
184 /* missing: R_X86_64_GOT32 R_X86_64_PLT32 */
185
186 case R_X86_64_COPY:
187 /*
188 * These are deferred until all other relocations have
189 * been done. All we do here is make sure that the COPY
190 * relocation is not in a shared library. They are allowed
191 * only in executable files.
192 */
193 if (!obj->mainprog) {
194 _rtld_error("%s: Unexpected R_X86_64_COPY relocation"
195 " in shared library", obj->path);
196 goto done;
197 }
198 break;
199
200 case R_X86_64_GLOB_DAT:
201 {
202 const Elf_Sym *def;
203 const Obj_Entry *defobj;
204
205 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
35b2b265 206 false, cache, lockstate);
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207 if (def == NULL)
208 goto done;
209
210 *where = (Elf_Addr) (defobj->relocbase + def->st_value);
211 }
212 break;
213
214 case R_X86_64_TPOFF64:
215 {
216 const Elf_Sym *def;
217 const Obj_Entry *defobj;
218
219 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
35b2b265 220 false, cache, lockstate);
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221 if (def == NULL)
222 goto done;
223
224 /*
225 * We lazily allocate offsets for static TLS as we
226 * see the first relocation that references the
227 * TLS block. This allows us to support (small
228 * amounts of) static TLS in dynamically loaded
229 * modules. If we run out of space, we generate an
230 * error.
231 */
232 if (!defobj->tls_done) {
233 if (!allocate_tls_offset((Obj_Entry*) defobj)) {
234 _rtld_error("%s: No space available for static "
235 "Thread Local Storage", obj->path);
236 goto done;
237 }
238 }
239
240 *where = (Elf_Addr) (def->st_value - defobj->tlsoffset +
241 rela->r_addend);
242 }
243 break;
244
245 case R_X86_64_TPOFF32:
246 {
247 const Elf_Sym *def;
248 const Obj_Entry *defobj;
249
250 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
35b2b265 251 false, cache, lockstate);
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252 if (def == NULL)
253 goto done;
254
255 /*
256 * We lazily allocate offsets for static TLS as we
257 * see the first relocation that references the
258 * TLS block. This allows us to support (small
259 * amounts of) static TLS in dynamically loaded
260 * modules. If we run out of space, we generate an
261 * error.
262 */
263 if (!defobj->tls_done) {
264 if (!allocate_tls_offset((Obj_Entry*) defobj)) {
265 _rtld_error("%s: No space available for static "
266 "Thread Local Storage", obj->path);
267 goto done;
268 }
269 }
270
271 *where32 = (Elf32_Addr) (def->st_value -
272 defobj->tlsoffset +
273 rela->r_addend);
274 }
275 break;
276
277 case R_X86_64_DTPMOD64:
278 {
279 const Elf_Sym *def;
280 const Obj_Entry *defobj;
281
282 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
35b2b265 283 false, cache, lockstate);
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284 if (def == NULL)
285 goto done;
286
287 *where += (Elf_Addr) defobj->tlsindex;
288 }
289 break;
290
291 case R_X86_64_DTPOFF64:
292 {
293 const Elf_Sym *def;
294 const Obj_Entry *defobj;
295
296 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
35b2b265 297 false, cache, lockstate);
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298 if (def == NULL)
299 goto done;
300
301 *where += (Elf_Addr) (def->st_value + rela->r_addend);
302 }
303 break;
304
305 case R_X86_64_DTPOFF32:
306 {
307 const Elf_Sym *def;
308 const Obj_Entry *defobj;
309
310 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
35b2b265 311 false, cache, lockstate);
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312 if (def == NULL)
313 goto done;
314
315 *where32 += (Elf32_Addr) (def->st_value + rela->r_addend);
316 }
317 break;
318
319 case R_X86_64_RELATIVE:
320 *where = (Elf_Addr)(obj->relocbase + rela->r_addend);
321 break;
322
323 /* missing: R_X86_64_GOTPCREL, R_X86_64_32, R_X86_64_32S, R_X86_64_16, R_X86_64_PC16, R_X86_64_8, R_X86_64_PC8 */
324
325 default:
326 _rtld_error("%s: Unsupported relocation type %u"
327 " in non-PLT relocations\n", obj->path,
328 (unsigned int)ELF_R_TYPE(rela->r_info));
329 goto done;
330 }
331 }
332 r = 0;
333done:
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334 if (cache != NULL)
335 free(cache);
f66e9c25
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336 return(r);
337}
338
339/* Process the PLT relocations. */
340int
341reloc_plt(Obj_Entry *obj)
342{
343 const Elf_Rela *relalim;
344 const Elf_Rela *rela;
345
346 relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
347 for (rela = obj->pltrela; rela < relalim; rela++) {
348 Elf_Addr *where;
349
f609f035
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350 switch(ELF_R_TYPE(rela->r_info)) {
351 case R_X86_64_JMP_SLOT:
352 /* Relocate the GOT slot pointing into the PLT. */
353 where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
354 *where += (Elf_Addr)obj->relocbase;
355 break;
356
357 default:
358 _rtld_error("Unknown relocation type %x in PLT",
359 (unsigned int)ELF_R_TYPE(rela->r_info));
360 return (-1);
361 }
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362 }
363 return 0;
364}
365
366/* Relocate the jump slots in an object. */
367int
35b2b265 368reloc_jmpslots(Obj_Entry *obj, RtldLockState *lockstate)
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369{
370 const Elf_Rela *relalim;
371 const Elf_Rela *rela;
372
373 if (obj->jmpslots_done)
374 return 0;
375 relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
376 for (rela = obj->pltrela; rela < relalim; rela++) {
377 Elf_Addr *where, target;
378 const Elf_Sym *def;
379 const Obj_Entry *defobj;
380
f609f035
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381 switch (ELF_R_TYPE(rela->r_info)) {
382 case R_X86_64_JMP_SLOT:
383 where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
35b2b265
JM
384 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true, NULL,
385 lockstate);
f609f035
JM
386 if (def == NULL)
387 return (-1);
388 target = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend);
389 reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela);
390 break;
391
392 default:
393 _rtld_error("Unknown relocation type %x in PLT",
394 (unsigned int)ELF_R_TYPE(rela->r_info));
395 return (-1);
396 }
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397 }
398 obj->jmpslots_done = true;
399 return 0;
400}
401
402void *__tls_get_addr(tls_index *ti)
403{
404 struct tls_tcb *tcb;
405
406 tcb = tls_get_tcb();
18d39a4f 407 return tls_get_addr_common((Elf_Addr **)&tcb->tcb_dtv, ti->ti_module, ti->ti_offset);
f66e9c25
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408}
409
410void *
411__tls_get_addr_tcb(struct tls_tcb *tcb, tls_index *ti)
412{
18d39a4f 413 return tls_get_addr_common((Elf_Addr **)&tcb->tcb_dtv, ti->ti_module, ti->ti_offset);
f66e9c25 414}