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 *
|
25 * $FreeBSD: head/libexec/rtld-elf/amd64/reloc.c 157198 2006-03-28 06:09:24Z davidxu $
|
| 25 * $FreeBSD: head/libexec/rtld-elf/amd64/reloc.c 208256 2010-05-18 08:55:23Z rdivacky $ |
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 <machine/sysarch.h>
37
38#include <dlfcn.h>
39#include <err.h>
40#include <errno.h>
41#include <fcntl.h>
42#include <stdarg.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47
48#include "debug.h"
49#include "rtld.h"
50
51/*
52 * Process the special R_X86_64_COPY relocations in the main program. These
53 * copy data from a shared object into a region in the main program's BSS
54 * segment.
55 *
56 * Returns 0 on success, -1 on failure.
57 */
58int
59do_copy_relocations(Obj_Entry *dstobj)
60{
61 const Elf_Rela *relalim;
62 const Elf_Rela *rela;
63
64 assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */
65
66 relalim = (const Elf_Rela *) ((caddr_t) dstobj->rela + dstobj->relasize);
67 for (rela = dstobj->rela; rela < relalim; rela++) {
68 if (ELF_R_TYPE(rela->r_info) == R_X86_64_COPY) {
69 void *dstaddr;
70 const Elf_Sym *dstsym;
71 const char *name;
72 unsigned long hash;
73 size_t size;
74 const void *srcaddr;
75 const Elf_Sym *srcsym;
76 Obj_Entry *srcobj;
77 const Ver_Entry *ve;
78
79 dstaddr = (void *) (dstobj->relocbase + rela->r_offset);
80 dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
81 name = dstobj->strtab + dstsym->st_name;
82 hash = elf_hash(name);
83 size = dstsym->st_size;
84 ve = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info));
85
86 for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next)
87 if ((srcsym = symlook_obj(name, hash, srcobj, ve, 0)) != NULL)
88 break;
89
90 if (srcobj == NULL) {
91 _rtld_error("Undefined symbol \"%s\" referenced from COPY"
92 " relocation in %s", name, dstobj->path);
93 return -1;
94 }
95
96 srcaddr = (const void *) (srcobj->relocbase + srcsym->st_value);
97 memcpy(dstaddr, srcaddr, size);
98 }
99 }
100
101 return 0;
102}
103
104/* Initialize the special GOT entries. */
105void
106init_pltgot(Obj_Entry *obj)
107{
108 if (obj->pltgot != NULL) {
109 obj->pltgot[1] = (Elf_Addr) obj;
110 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
111 }
112}
113
114/* Process the non-PLT relocations. */
115int
116reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld)
117{
118 const Elf_Rela *relalim;
119 const Elf_Rela *rela;
120 SymCache *cache;
|
121 int bytes = obj->nchains * sizeof(SymCache);
|
121 int r = -1;
122
123 /*
124 * The dynamic loader may be called from a thread, we have
125 * limited amounts of stack available so we cannot use alloca().
126 */
|
128 cache = mmap(NULL, bytes, PROT_READ|PROT_WRITE, MAP_ANON, -1, 0);
129 if (cache == MAP_FAILED)
|
127 if (obj != obj_rtld) {
128 cache = calloc(obj->nchains, sizeof(SymCache));
129 /* No need to check for NULL here */
130 } else |
131 cache = NULL;
132
133 relalim = (const Elf_Rela *) ((caddr_t) obj->rela + obj->relasize);
134 for (rela = obj->rela; rela < relalim; rela++) {
135 Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
136 Elf32_Addr *where32 = (Elf32_Addr *)where;
137
138 switch (ELF_R_TYPE(rela->r_info)) {
139
140 case R_X86_64_NONE:
141 break;
142
143 case R_X86_64_64:
144 {
145 const Elf_Sym *def;
146 const Obj_Entry *defobj;
147
148 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
149 false, cache);
150 if (def == NULL)
151 goto done;
152
153 *where = (Elf_Addr) (defobj->relocbase + def->st_value + rela->r_addend);
154 }
155 break;
156
157 case R_X86_64_PC32:
158 /*
159 * I don't think the dynamic linker should ever see this
160 * type of relocation. But the binutils-2.6 tools sometimes
161 * generate it.
162 */
163 {
164 const Elf_Sym *def;
165 const Obj_Entry *defobj;
166
167 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
168 false, cache);
169 if (def == NULL)
170 goto done;
171
172 *where32 = (Elf32_Addr) (unsigned long) (defobj->relocbase +
173 def->st_value + rela->r_addend - (Elf_Addr) where);
174 }
175 break;
176 /* missing: R_X86_64_GOT32 R_X86_64_PLT32 */
177
178 case R_X86_64_COPY:
179 /*
180 * These are deferred until all other relocations have
181 * been done. All we do here is make sure that the COPY
182 * relocation is not in a shared library. They are allowed
183 * only in executable files.
184 */
185 if (!obj->mainprog) {
186 _rtld_error("%s: Unexpected R_X86_64_COPY relocation"
187 " in shared library", obj->path);
188 goto done;
189 }
190 break;
191
192 case R_X86_64_GLOB_DAT:
193 {
194 const Elf_Sym *def;
195 const Obj_Entry *defobj;
196
197 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
198 false, cache);
199 if (def == NULL)
200 goto done;
201
202 *where = (Elf_Addr) (defobj->relocbase + def->st_value);
203 }
204 break;
205
206 case R_X86_64_TPOFF64:
207 {
208 const Elf_Sym *def;
209 const Obj_Entry *defobj;
210
211 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
212 false, cache);
213 if (def == NULL)
214 goto done;
215
216 /*
217 * We lazily allocate offsets for static TLS as we
218 * see the first relocation that references the
219 * TLS block. This allows us to support (small
220 * amounts of) static TLS in dynamically loaded
221 * modules. If we run out of space, we generate an
222 * error.
223 */
224 if (!defobj->tls_done) {
225 if (!allocate_tls_offset((Obj_Entry*) defobj)) {
226 _rtld_error("%s: No space available for static "
227 "Thread Local Storage", obj->path);
228 goto done;
229 }
230 }
231
232 *where = (Elf_Addr) (def->st_value - defobj->tlsoffset +
233 rela->r_addend);
234 }
235 break;
236
237 case R_X86_64_TPOFF32:
238 {
239 const Elf_Sym *def;
240 const Obj_Entry *defobj;
241
242 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
243 false, cache);
244 if (def == NULL)
245 goto done;
246
247 /*
248 * We lazily allocate offsets for static TLS as we
249 * see the first relocation that references the
250 * TLS block. This allows us to support (small
251 * amounts of) static TLS in dynamically loaded
252 * modules. If we run out of space, we generate an
253 * error.
254 */
255 if (!defobj->tls_done) {
256 if (!allocate_tls_offset((Obj_Entry*) defobj)) {
257 _rtld_error("%s: No space available for static "
258 "Thread Local Storage", obj->path);
259 goto done;
260 }
261 }
262
263 *where32 = (Elf32_Addr) (def->st_value -
264 defobj->tlsoffset +
265 rela->r_addend);
266 }
267 break;
268
269 case R_X86_64_DTPMOD64:
270 {
271 const Elf_Sym *def;
272 const Obj_Entry *defobj;
273
274 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
275 false, cache);
276 if (def == NULL)
277 goto done;
278
279 *where += (Elf_Addr) defobj->tlsindex;
280 }
281 break;
282
283 case R_X86_64_DTPOFF64:
284 {
285 const Elf_Sym *def;
286 const Obj_Entry *defobj;
287
288 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
289 false, cache);
290 if (def == NULL)
291 goto done;
292
293 *where += (Elf_Addr) (def->st_value + rela->r_addend);
294 }
295 break;
296
297 case R_X86_64_DTPOFF32:
298 {
299 const Elf_Sym *def;
300 const Obj_Entry *defobj;
301
302 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
303 false, cache);
304 if (def == NULL)
305 goto done;
306
307 *where32 += (Elf32_Addr) (def->st_value + rela->r_addend);
308 }
309 break;
310
311 case R_X86_64_RELATIVE:
312 *where = (Elf_Addr)(obj->relocbase + rela->r_addend);
313 break;
314
315 /* 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 */
316
317 default:
318 _rtld_error("%s: Unsupported relocation type %u"
319 " in non-PLT relocations\n", obj->path,
320 (unsigned int)ELF_R_TYPE(rela->r_info));
321 goto done;
322 }
323 }
324 r = 0;
325done:
|
325 if (cache)
326 munmap(cache, bytes);
|
326 if (cache != NULL)
327 free(cache); |
328 return(r);
329}
330
331/* Process the PLT relocations. */
332int
333reloc_plt(Obj_Entry *obj)
334{
335 const Elf_Rela *relalim;
336 const Elf_Rela *rela;
337
338 relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
339 for (rela = obj->pltrela; rela < relalim; rela++) {
340 Elf_Addr *where;
341
342 assert(ELF_R_TYPE(rela->r_info) == R_X86_64_JMP_SLOT);
343
344 /* Relocate the GOT slot pointing into the PLT. */
345 where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
346 *where += (Elf_Addr)obj->relocbase;
347 }
348 return 0;
349}
350
351/* Relocate the jump slots in an object. */
352int
353reloc_jmpslots(Obj_Entry *obj)
354{
355 const Elf_Rela *relalim;
356 const Elf_Rela *rela;
357
358 if (obj->jmpslots_done)
359 return 0;
360 relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
361 for (rela = obj->pltrela; rela < relalim; rela++) {
362 Elf_Addr *where, target;
363 const Elf_Sym *def;
364 const Obj_Entry *defobj;
365
366 assert(ELF_R_TYPE(rela->r_info) == R_X86_64_JMP_SLOT);
367 where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
368 def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true, NULL);
369 if (def == NULL)
370 return -1;
371 target = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend);
372 reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela);
373 }
374 obj->jmpslots_done = true;
375 return 0;
376}
377
378void
379allocate_initial_tls(Obj_Entry *objs)
380{
381 /*
382 * Fix the size of the static TLS block by using the maximum
383 * offset allocated so far and adding a bit for dynamic modules to
384 * use.
385 */
386 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
387 amd64_set_fsbase(allocate_tls(objs, 0,
388 3*sizeof(Elf_Addr), sizeof(Elf_Addr)));
389}
390
391void *__tls_get_addr(tls_index *ti)
392{
393 Elf_Addr** segbase;
394 Elf_Addr* dtv;
395
396 __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
397 dtv = segbase[1];
398
399 return tls_get_addr_common(&segbase[1], ti->ti_module, ti->ti_offset);
400}
|