reloc.c revision 1.36 1 1.36 fvdl /* $NetBSD: reloc.c,v 1.36 2001/06/19 01:11:03 fvdl Exp $ */
2 1.1 cgd
3 1.1 cgd /*
4 1.1 cgd * Copyright 1996 John D. Polstra.
5 1.1 cgd * Copyright 1996 Matt Thomas <matt (at) 3am-software.com>
6 1.1 cgd * All rights reserved.
7 1.1 cgd *
8 1.1 cgd * Redistribution and use in source and binary forms, with or without
9 1.1 cgd * modification, are permitted provided that the following conditions
10 1.1 cgd * are met:
11 1.1 cgd * 1. Redistributions of source code must retain the above copyright
12 1.1 cgd * notice, this list of conditions and the following disclaimer.
13 1.1 cgd * 2. Redistributions in binary form must reproduce the above copyright
14 1.1 cgd * notice, this list of conditions and the following disclaimer in the
15 1.1 cgd * documentation and/or other materials provided with the distribution.
16 1.1 cgd * 3. All advertising materials mentioning features or use of this software
17 1.1 cgd * must display the following acknowledgement:
18 1.1 cgd * This product includes software developed by John Polstra.
19 1.1 cgd * 4. The name of the author may not be used to endorse or promote products
20 1.1 cgd * derived from this software without specific prior written permission.
21 1.1 cgd *
22 1.1 cgd * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 1.1 cgd * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 1.1 cgd * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 1.1 cgd * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 1.1 cgd * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 1.1 cgd * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 1.1 cgd * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 1.1 cgd * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 1.1 cgd * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 1.1 cgd * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 1.1 cgd */
33 1.1 cgd
34 1.1 cgd /*
35 1.1 cgd * Dynamic linker for ELF.
36 1.1 cgd *
37 1.1 cgd * John Polstra <jdp (at) polstra.com>.
38 1.1 cgd */
39 1.1 cgd
40 1.1 cgd #include <err.h>
41 1.1 cgd #include <errno.h>
42 1.1 cgd #include <fcntl.h>
43 1.1 cgd #include <stdarg.h>
44 1.1 cgd #include <stdio.h>
45 1.1 cgd #include <stdlib.h>
46 1.1 cgd #include <string.h>
47 1.1 cgd #include <unistd.h>
48 1.1 cgd #include <sys/types.h>
49 1.1 cgd #include <sys/mman.h>
50 1.1 cgd #include <dirent.h>
51 1.1 cgd
52 1.1 cgd #include "debug.h"
53 1.1 cgd #include "rtld.h"
54 1.1 cgd
55 1.14 pk #ifndef RTLD_INHIBIT_COPY_RELOCS
56 1.35 kleink static int _rtld_do_copy_relocation __P((const Obj_Entry *, const Elf_Rela *,
57 1.16 christos bool));
58 1.16 christos
59 1.4 christos /*
60 1.4 christos * XXX: These don't work for the alpha and i386; don't know about powerpc
61 1.4 christos * The alpha and the i386 avoid the problem by compiling everything PIC.
62 1.4 christos * These relocation are supposed to be writing the address of the
63 1.4 christos * function to be called on the bss.rel or bss.rela segment, but:
64 1.4 christos * - st_size == 0
65 1.4 christos * - on the i386 at least the call instruction is a direct call
66 1.4 christos * not an indirect call.
67 1.4 christos */
68 1.1 cgd static int
69 1.16 christos _rtld_do_copy_relocation(dstobj, rela, dodebug)
70 1.16 christos const Obj_Entry *dstobj;
71 1.35 kleink const Elf_Rela *rela;
72 1.16 christos bool dodebug;
73 1.1 cgd {
74 1.11 christos void *dstaddr = (void *)(dstobj->relocbase + rela->r_offset);
75 1.11 christos const Elf_Sym *dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
76 1.11 christos const char *name = dstobj->strtab + dstsym->st_name;
77 1.11 christos unsigned long hash = _rtld_elf_hash(name);
78 1.11 christos size_t size = dstsym->st_size;
79 1.11 christos const void *srcaddr;
80 1.11 christos const Elf_Sym *srcsym;
81 1.11 christos Obj_Entry *srcobj;
82 1.11 christos
83 1.11 christos for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next)
84 1.11 christos if ((srcsym = _rtld_symlook_obj(name, hash, srcobj,
85 1.11 christos false)) != NULL)
86 1.11 christos break;
87 1.11 christos
88 1.11 christos if (srcobj == NULL) {
89 1.11 christos _rtld_error("Undefined symbol \"%s\" referenced from COPY"
90 1.11 christos " relocation in %s", name, dstobj->path);
91 1.14 pk return (-1);
92 1.11 christos }
93 1.11 christos srcaddr = (const void *)(srcobj->relocbase + srcsym->st_value);
94 1.11 christos (void)memcpy(dstaddr, srcaddr, size);
95 1.18 christos rdbg(dodebug, ("COPY %s %s %s --> src=%p dst=%p *dst= %p size %ld",
96 1.11 christos dstobj->path, srcobj->path, name, (void *)srcaddr,
97 1.18 christos (void *)dstaddr, (void *)*(long *)dstaddr, (long)size));
98 1.14 pk return (0);
99 1.1 cgd }
100 1.14 pk #endif /* RTLD_INHIBIT_COPY_RELOCS */
101 1.11 christos
102 1.11 christos
103 1.1 cgd /*
104 1.1 cgd * Process the special R_xxx_COPY relocations in the main program. These
105 1.1 cgd * copy data from a shared object into a region in the main program's BSS
106 1.1 cgd * segment.
107 1.1 cgd *
108 1.1 cgd * Returns 0 on success, -1 on failure.
109 1.1 cgd */
110 1.1 cgd int
111 1.16 christos _rtld_do_copy_relocations(dstobj, dodebug)
112 1.16 christos const Obj_Entry *dstobj;
113 1.16 christos bool dodebug;
114 1.1 cgd {
115 1.14 pk #ifndef RTLD_INHIBIT_COPY_RELOCS
116 1.14 pk
117 1.14 pk /* COPY relocations are invalid elsewhere */
118 1.14 pk assert(dstobj->mainprog);
119 1.1 cgd
120 1.11 christos if (dstobj->rel != NULL) {
121 1.11 christos const Elf_Rel *rel;
122 1.11 christos for (rel = dstobj->rel; rel < dstobj->rellim; ++rel) {
123 1.11 christos if (ELF_R_TYPE(rel->r_info) == R_TYPE(COPY)) {
124 1.35 kleink Elf_Rela ourrela;
125 1.11 christos ourrela.r_info = rel->r_info;
126 1.11 christos ourrela.r_offset = rel->r_offset;
127 1.11 christos ourrela.r_addend = 0;
128 1.11 christos if (_rtld_do_copy_relocation(dstobj,
129 1.11 christos &ourrela, dodebug) < 0)
130 1.14 pk return (-1);
131 1.11 christos }
132 1.11 christos }
133 1.11 christos }
134 1.11 christos if (dstobj->rela != NULL) {
135 1.35 kleink const Elf_Rela *rela;
136 1.11 christos for (rela = dstobj->rela; rela < dstobj->relalim; ++rela) {
137 1.11 christos if (ELF_R_TYPE(rela->r_info) == R_TYPE(COPY)) {
138 1.11 christos if (_rtld_do_copy_relocation(dstobj, rela,
139 1.11 christos dodebug) < 0)
140 1.14 pk return (-1);
141 1.11 christos }
142 1.11 christos }
143 1.1 cgd }
144 1.14 pk #endif /* RTLD_INHIBIT_COPY_RELOCS */
145 1.1 cgd
146 1.14 pk return (0);
147 1.1 cgd }
148 1.9 pk
149 1.9 pk
150 1.36 fvdl #if !defined(__sparc__) && !defined(__x86_64__)
151 1.34 christos
152 1.34 christos #if defined(__alpha__) || defined(__i386__) || defined(__m68k__)
153 1.34 christos extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
154 1.34 christos extern Elf_Dyn _DYNAMIC;
155 1.34 christos #endif
156 1.34 christos
157 1.11 christos int
158 1.16 christos _rtld_relocate_nonplt_object(obj, rela, dodebug)
159 1.23 mycroft Obj_Entry *obj;
160 1.35 kleink const Elf_Rela *rela;
161 1.16 christos bool dodebug;
162 1.9 pk {
163 1.11 christos Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
164 1.11 christos const Elf_Sym *def;
165 1.9 pk const Obj_Entry *defobj;
166 1.20 kleink #if defined(__alpha__) || defined(__i386__) || defined(__m68k__) || \
167 1.21 matt defined(__powerpc__) || defined(__vax__)
168 1.11 christos Elf_Addr tmp;
169 1.17 jonathan #endif
170 1.9 pk
171 1.11 christos switch (ELF_R_TYPE(rela->r_info)) {
172 1.9 pk
173 1.11 christos case R_TYPE(NONE):
174 1.11 christos break;
175 1.9 pk
176 1.24 itohy #if defined(__i386__)
177 1.11 christos case R_TYPE(GOT32):
178 1.9 pk
179 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
180 1.11 christos &defobj, false);
181 1.11 christos if (def == NULL)
182 1.11 christos return -1;
183 1.9 pk
184 1.11 christos tmp = (Elf_Addr)(defobj->relocbase + def->st_value);
185 1.11 christos if (*where != tmp)
186 1.11 christos *where = tmp;
187 1.16 christos rdbg(dodebug, ("GOT32 %s in %s --> %p in %s",
188 1.11 christos defobj->strtab + def->st_name, obj->path,
189 1.16 christos (void *)*where, defobj->path));
190 1.11 christos break;
191 1.9 pk
192 1.11 christos case R_TYPE(PC32):
193 1.11 christos /*
194 1.11 christos * I don't think the dynamic linker should ever see this
195 1.11 christos * type of relocation. But the binutils-2.6 tools sometimes
196 1.11 christos * generate it.
197 1.11 christos */
198 1.9 pk
199 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
200 1.11 christos &defobj, false);
201 1.11 christos if (def == NULL)
202 1.11 christos return -1;
203 1.9 pk
204 1.11 christos *where += (Elf_Addr)(defobj->relocbase + def->st_value) -
205 1.11 christos (Elf_Addr)where;
206 1.16 christos rdbg(dodebug, ("PC32 %s in %s --> %p in %s",
207 1.11 christos defobj->strtab + def->st_name, obj->path,
208 1.16 christos (void *)*where, defobj->path));
209 1.11 christos break;
210 1.11 christos
211 1.11 christos case R_TYPE(32):
212 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
213 1.11 christos &defobj, false);
214 1.11 christos if (def == NULL)
215 1.11 christos return -1;
216 1.9 pk
217 1.11 christos *where += (Elf_Addr)(defobj->relocbase + def->st_value);
218 1.16 christos rdbg(dodebug, ("32 %s in %s --> %p in %s",
219 1.11 christos defobj->strtab + def->st_name, obj->path,
220 1.16 christos (void *)*where, defobj->path));
221 1.11 christos break;
222 1.24 itohy #endif /* __i386__ */
223 1.24 itohy
224 1.24 itohy #if defined(__m68k__)
225 1.24 itohy case R_TYPE(GOT32):
226 1.24 itohy def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
227 1.24 itohy &defobj, false);
228 1.24 itohy if (def == NULL)
229 1.24 itohy return -1;
230 1.24 itohy
231 1.24 itohy tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
232 1.24 itohy rela->r_addend);
233 1.24 itohy if (*where != tmp)
234 1.24 itohy *where = tmp;
235 1.24 itohy rdbg(dodebug, ("GOT32 %s in %s --> %p in %s",
236 1.24 itohy defobj->strtab + def->st_name, obj->path,
237 1.24 itohy (void *)*where, defobj->path));
238 1.24 itohy break;
239 1.24 itohy
240 1.24 itohy case R_TYPE(PC32):
241 1.24 itohy def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
242 1.24 itohy &defobj, false);
243 1.24 itohy if (def == NULL)
244 1.24 itohy return -1;
245 1.24 itohy
246 1.24 itohy tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
247 1.24 itohy rela->r_addend) - (Elf_Addr)where;
248 1.24 itohy if (*where != tmp)
249 1.24 itohy *where = tmp;
250 1.24 itohy rdbg(dodebug, ("PC32 %s in %s --> %p in %s",
251 1.24 itohy defobj->strtab + def->st_name, obj->path,
252 1.24 itohy (void *)*where, defobj->path));
253 1.24 itohy break;
254 1.24 itohy
255 1.24 itohy case R_TYPE(32):
256 1.24 itohy def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
257 1.24 itohy &defobj, false);
258 1.24 itohy if (def == NULL)
259 1.24 itohy return -1;
260 1.24 itohy
261 1.24 itohy tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
262 1.24 itohy rela->r_addend);
263 1.24 itohy if (*where != tmp)
264 1.24 itohy *where = tmp;
265 1.24 itohy rdbg(dodebug, ("32 %s in %s --> %p in %s",
266 1.24 itohy defobj->strtab + def->st_name, obj->path,
267 1.24 itohy (void *)*where, defobj->path));
268 1.24 itohy break;
269 1.24 itohy #endif /* __m68k__ */
270 1.4 christos
271 1.21 matt #if defined(__alpha__)
272 1.11 christos case R_TYPE(REFQUAD):
273 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
274 1.11 christos &defobj, false);
275 1.11 christos if (def == NULL)
276 1.11 christos return -1;
277 1.1 cgd
278 1.11 christos tmp = (Elf_Addr)(defobj->relocbase + def->st_value) +
279 1.11 christos *where + rela->r_addend;
280 1.12 tv if (*where != tmp)
281 1.12 tv *where = tmp;
282 1.16 christos rdbg(dodebug, ("REFQUAD %s in %s --> %p in %s",
283 1.11 christos defobj->strtab + def->st_name, obj->path,
284 1.16 christos (void *)*where, defobj->path));
285 1.11 christos break;
286 1.4 christos #endif /* __alpha__ */
287 1.1 cgd
288 1.20 kleink #if defined(__alpha__) || defined(__i386__) || defined(__m68k__)
289 1.11 christos case R_TYPE(GLOB_DAT):
290 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
291 1.11 christos &defobj, false);
292 1.11 christos if (def == NULL)
293 1.11 christos return -1;
294 1.1 cgd
295 1.11 christos if (*where != (Elf_Addr)(defobj->relocbase + def->st_value))
296 1.11 christos *where = (Elf_Addr)(defobj->relocbase + def->st_value);
297 1.16 christos rdbg(dodebug, ("GLOB_DAT %s in %s --> %p in %s",
298 1.11 christos defobj->strtab + def->st_name, obj->path,
299 1.16 christos (void *)*where, defobj->path));
300 1.11 christos break;
301 1.11 christos
302 1.11 christos case R_TYPE(RELATIVE):
303 1.19 christos if (!dodebug ||
304 1.19 christos (caddr_t)where < (caddr_t)_GLOBAL_OFFSET_TABLE_ ||
305 1.11 christos (caddr_t)where >= (caddr_t)&_DYNAMIC) {
306 1.11 christos *where += (Elf_Addr)obj->relocbase;
307 1.16 christos rdbg(dodebug, ("RELATIVE in %s --> %p", obj->path,
308 1.16 christos (void *)*where));
309 1.11 christos }
310 1.11 christos else
311 1.16 christos rdbg(dodebug, ("RELATIVE in %s stays at %p",
312 1.16 christos obj->path, (void *)*where));
313 1.11 christos break;
314 1.1 cgd
315 1.11 christos case R_TYPE(COPY):
316 1.11 christos /*
317 1.11 christos * These are deferred until all other relocations have
318 1.11 christos * been done. All we do here is make sure that the COPY
319 1.11 christos * relocation is not in a shared library. They are allowed
320 1.11 christos * only in executable files.
321 1.11 christos */
322 1.11 christos if (!obj->mainprog) {
323 1.11 christos _rtld_error(
324 1.11 christos "%s: Unexpected R_COPY relocation in shared library",
325 1.11 christos obj->path);
326 1.11 christos return -1;
327 1.11 christos }
328 1.16 christos rdbg(dodebug, ("COPY (avoid in main)"));
329 1.11 christos break;
330 1.28 matt #endif /* __i386__ || __alpha__ || __m68k__ */
331 1.2 mhitch
332 1.21 matt #if defined(__mips__)
333 1.11 christos case R_TYPE(REL32):
334 1.11 christos /* 32-bit PC-relative reference */
335 1.11 christos def = obj->symtab + ELF_R_SYM(rela->r_info);
336 1.11 christos
337 1.22 simonb if (ELFDEFNNAME(ST_BIND)(def->st_info) == STB_LOCAL &&
338 1.22 simonb (ELFDEFNNAME(ST_TYPE)(def->st_info) == STT_SECTION ||
339 1.22 simonb ELFDEFNNAME(ST_TYPE)(def->st_info) == STT_NOTYPE)) {
340 1.11 christos *where += (Elf_Addr)obj->relocbase;
341 1.16 christos rdbg(dodebug, ("REL32 in %s --> %p", obj->path,
342 1.16 christos (void *)*where));
343 1.11 christos } else {
344 1.11 christos /* XXX maybe do something re: bootstrapping? */
345 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info,
346 1.11 christos NULL, obj, &defobj, false);
347 1.11 christos if (def == NULL)
348 1.11 christos return -1;
349 1.11 christos *where += (Elf_Addr)(defobj->relocbase + def->st_value);
350 1.16 christos rdbg(dodebug, ("REL32 %s in %s --> %p in %s",
351 1.11 christos defobj->strtab + def->st_name, obj->path,
352 1.16 christos (void *)*where, defobj->path));
353 1.11 christos }
354 1.11 christos break;
355 1.2 mhitch
356 1.11 christos #endif /* __mips__ */
357 1.1 cgd
358 1.21 matt #if defined(__powerpc__) || defined(__vax__)
359 1.11 christos case R_TYPE(32): /* word32 S + A */
360 1.11 christos case R_TYPE(GLOB_DAT): /* word32 S + A */
361 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
362 1.11 christos &defobj, false);
363 1.11 christos if (def == NULL)
364 1.11 christos return -1;
365 1.3 tsubai
366 1.11 christos tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
367 1.11 christos rela->r_addend);
368 1.3 tsubai
369 1.11 christos if (*where != tmp)
370 1.11 christos *where = tmp;
371 1.16 christos rdbg(dodebug, ("32/GLOB_DAT %s in %s --> %p in %s",
372 1.11 christos defobj->strtab + def->st_name, obj->path,
373 1.16 christos (void *)*where, defobj->path));
374 1.11 christos break;
375 1.11 christos
376 1.11 christos case R_TYPE(COPY):
377 1.16 christos rdbg(dodebug, ("COPY"));
378 1.11 christos break;
379 1.11 christos
380 1.11 christos case R_TYPE(JMP_SLOT):
381 1.16 christos rdbg(dodebug, ("JMP_SLOT"));
382 1.11 christos break;
383 1.11 christos
384 1.11 christos case R_TYPE(RELATIVE): /* word32 B + A */
385 1.11 christos tmp = (Elf_Addr)(obj->relocbase + rela->r_addend);
386 1.21 matt if (*where != tmp)
387 1.21 matt *where = tmp;
388 1.16 christos rdbg(dodebug, ("RELATIVE in %s --> %p", obj->path,
389 1.16 christos (void *)*where));
390 1.11 christos break;
391 1.21 matt #endif /* __powerpc__ || __vax__ */
392 1.26 kleink
393 1.26 kleink #if defined(__powerpc__)
394 1.26 kleink case R_TYPE(16_LO): /* #lo(S + A) */
395 1.26 kleink tmp = (Elf_Addr)(obj->relocbase + rela->r_addend);
396 1.26 kleink if (*(Elf32_Half *)where != tmp)
397 1.26 kleink *(Elf32_Half *)where = tmp;
398 1.26 kleink rdbg(dodebug, ("16_LO in %s --> %p", obj->path,
399 1.26 kleink (void *)*where));
400 1.26 kleink break;
401 1.26 kleink
402 1.26 kleink case R_TYPE(16_HI): /* #hi(S + A) */
403 1.26 kleink tmp = (Elf_Addr)(obj->relocbase + rela->r_addend) >> 16;
404 1.26 kleink if (*(Elf32_Half *)where != tmp)
405 1.26 kleink *(Elf32_Half *)where = tmp;
406 1.26 kleink rdbg(dodebug, ("16_HI in %s --> %p", obj->path,
407 1.26 kleink (void *)*where));
408 1.26 kleink break;
409 1.26 kleink
410 1.26 kleink case R_TYPE(16_HA): /* #ha(S + A) */
411 1.26 kleink tmp = (Elf_Addr)(obj->relocbase + rela->r_addend + 0x8000)
412 1.26 kleink >> 16;
413 1.26 kleink if (*(Elf32_Half *)where != tmp)
414 1.26 kleink *(Elf32_Half *)where = tmp;
415 1.26 kleink rdbg(dodebug, ("16_HA in %s --> %p", obj->path,
416 1.26 kleink (void *)*where));
417 1.26 kleink break;
418 1.26 kleink #endif /* __powerpc__ */
419 1.21 matt
420 1.11 christos default:
421 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
422 1.11 christos &defobj, true);
423 1.16 christos rdbg(dodebug, ("sym = %lu, type = %lu, offset = %p, "
424 1.11 christos "addend = %p, contents = %p, symbol = %s",
425 1.11 christos (u_long)ELF_R_SYM(rela->r_info),
426 1.11 christos (u_long)ELF_R_TYPE(rela->r_info),
427 1.11 christos (void *)rela->r_offset, (void *)rela->r_addend,
428 1.11 christos (void *)*where,
429 1.16 christos def ? defobj->strtab + def->st_name : "??"));
430 1.33 dan _rtld_error("%s: Unsupported relocation type %ld "
431 1.11 christos "in non-PLT relocations\n",
432 1.33 dan obj->path, (u_long) ELF_R_TYPE(rela->r_info));
433 1.11 christos return -1;
434 1.11 christos }
435 1.11 christos return 0;
436 1.1 cgd }
437 1.9 pk
438 1.9 pk
439 1.9 pk
440 1.11 christos int
441 1.16 christos _rtld_relocate_plt_object(obj, rela, addrp, bind_now, dodebug)
442 1.23 mycroft Obj_Entry *obj;
443 1.35 kleink const Elf_Rela *rela;
444 1.16 christos caddr_t *addrp;
445 1.16 christos bool bind_now;
446 1.16 christos bool dodebug;
447 1.1 cgd {
448 1.16 christos Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
449 1.16 christos Elf_Addr new_value;
450 1.1 cgd
451 1.11 christos /* Fully resolve procedure addresses now */
452 1.2 mhitch
453 1.3 tsubai #if defined(__powerpc__)
454 1.11 christos return _rtld_reloc_powerpc_plt(obj, rela, bind_now);
455 1.3 tsubai #endif
456 1.3 tsubai
457 1.21 matt #if defined(__alpha__) || defined(__i386__) || defined(__m68k__) || \
458 1.21 matt defined(__vax__)
459 1.11 christos if (bind_now || obj->pltgot == NULL) {
460 1.11 christos const Elf_Sym *def;
461 1.11 christos const Obj_Entry *defobj;
462 1.11 christos
463 1.11 christos assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
464 1.1 cgd
465 1.11 christos def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj,
466 1.11 christos &defobj, true);
467 1.11 christos if (def == NULL)
468 1.11 christos return -1;
469 1.1 cgd
470 1.11 christos new_value = (Elf_Addr)(defobj->relocbase + def->st_value);
471 1.29 matt #if defined(__vax__)
472 1.29 matt new_value += rela->r_addend;
473 1.29 matt #endif
474 1.16 christos rdbg(dodebug, ("bind now %d/fixup in %s --> old=%p new=%p",
475 1.11 christos (int)bind_now,
476 1.11 christos defobj->strtab + def->st_name,
477 1.16 christos (void *)*where, (void *)new_value));
478 1.11 christos } else
479 1.21 matt #endif /* __alpha__ || __i386__ || __m68k__ || __vax__ */
480 1.11 christos if (!obj->mainprog) {
481 1.11 christos /* Just relocate the GOT slots pointing into the PLT */
482 1.11 christos new_value = *where + (Elf_Addr)(obj->relocbase);
483 1.16 christos rdbg(dodebug, ("fixup !main in %s --> %p", obj->path,
484 1.16 christos (void *)*where));
485 1.11 christos } else {
486 1.11 christos return 0;
487 1.11 christos }
488 1.11 christos /*
489 1.11 christos * Since this page is probably copy-on-write, let's not write
490 1.11 christos * it unless we really really have to.
491 1.11 christos */
492 1.11 christos if (*where != new_value)
493 1.11 christos *where = new_value;
494 1.29 matt if (addrp != NULL) {
495 1.11 christos *addrp = *(caddr_t *)(obj->relocbase + rela->r_offset);
496 1.29 matt #if defined(__vax__)
497 1.29 matt *addrp -= rela->r_addend;
498 1.29 matt #endif
499 1.29 matt }
500 1.7 tv return 0;
501 1.1 cgd }
502 1.11 christos #endif /* __sparc__ */
503 1.9 pk
504 1.1 cgd caddr_t
505 1.16 christos _rtld_bind(obj, reloff)
506 1.23 mycroft Obj_Entry *obj;
507 1.16 christos Elf_Word reloff;
508 1.1 cgd {
509 1.35 kleink const Elf_Rela *rela;
510 1.35 kleink Elf_Rela ourrela;
511 1.11 christos caddr_t addr;
512 1.1 cgd
513 1.11 christos if (obj->pltrel != NULL) {
514 1.11 christos const Elf_Rel *rel;
515 1.1 cgd
516 1.11 christos rel = (const Elf_Rel *)((caddr_t) obj->pltrel + reloff);
517 1.11 christos ourrela.r_info = rel->r_info;
518 1.11 christos ourrela.r_offset = rel->r_offset;
519 1.28 matt ourrela.r_addend = 0;
520 1.11 christos rela = &ourrela;
521 1.11 christos } else {
522 1.35 kleink rela = (const Elf_Rela *)((caddr_t) obj->pltrela + reloff);
523 1.11 christos }
524 1.11 christos
525 1.11 christos if (_rtld_relocate_plt_object(obj, rela, &addr, true, true) < 0)
526 1.11 christos _rtld_die();
527 1.1 cgd
528 1.11 christos return addr;
529 1.1 cgd }
530 1.9 pk
531 1.1 cgd /*
532 1.1 cgd * Relocate newly-loaded shared objects. The argument is a pointer to
533 1.1 cgd * the Obj_Entry for the first such object. All objects from the first
534 1.1 cgd * to the end of the list of objects are relocated. Returns 0 on success,
535 1.1 cgd * or -1 on failure.
536 1.1 cgd */
537 1.1 cgd int
538 1.16 christos _rtld_relocate_objects(first, bind_now, dodebug)
539 1.16 christos Obj_Entry *first;
540 1.16 christos bool bind_now;
541 1.16 christos bool dodebug;
542 1.1 cgd {
543 1.16 christos Obj_Entry *obj;
544 1.16 christos int ok = 1;
545 1.1 cgd
546 1.11 christos for (obj = first; obj != NULL; obj = obj->next) {
547 1.16 christos if (obj->nbuckets == 0 || obj->nchains == 0 ||
548 1.16 christos obj->buckets == NULL || obj->symtab == NULL ||
549 1.16 christos obj->strtab == NULL) {
550 1.11 christos _rtld_error("%s: Shared object has no run-time"
551 1.11 christos " symbol table", obj->path);
552 1.11 christos return -1;
553 1.11 christos }
554 1.16 christos rdbg(dodebug, (" relocating %s (%ld/%ld rel/rela, "
555 1.11 christos "%ld/%ld plt rel/rela)",
556 1.11 christos obj->path,
557 1.11 christos (long)(obj->rellim - obj->rel),
558 1.11 christos (long)(obj->relalim - obj->rela),
559 1.11 christos (long)(obj->pltrellim - obj->pltrel),
560 1.16 christos (long)(obj->pltrelalim - obj->pltrela)));
561 1.11 christos
562 1.11 christos if (obj->textrel) {
563 1.11 christos /*
564 1.11 christos * There are relocations to the write-protected text
565 1.11 christos * segment.
566 1.11 christos */
567 1.11 christos if (mprotect(obj->mapbase, obj->textsize,
568 1.11 christos PROT_READ | PROT_WRITE | PROT_EXEC) == -1) {
569 1.11 christos _rtld_error("%s: Cannot write-enable text "
570 1.11 christos "segment: %s", obj->path, xstrerror(errno));
571 1.11 christos return -1;
572 1.11 christos }
573 1.11 christos }
574 1.11 christos if (obj->rel != NULL) {
575 1.11 christos /* Process the non-PLT relocations. */
576 1.11 christos const Elf_Rel *rel;
577 1.11 christos for (rel = obj->rel; rel < obj->rellim; ++rel) {
578 1.35 kleink Elf_Rela ourrela;
579 1.11 christos ourrela.r_info = rel->r_info;
580 1.11 christos ourrela.r_offset = rel->r_offset;
581 1.2 mhitch #if defined(__mips__)
582 1.11 christos /* rel->r_offset is not valid on mips? */
583 1.11 christos if (ELF_R_TYPE(ourrela.r_info) == R_TYPE(NONE))
584 1.11 christos ourrela.r_addend = 0;
585 1.11 christos else
586 1.11 christos #endif
587 1.11 christos ourrela.r_addend =
588 1.11 christos *(Elf_Word *)(obj->relocbase +
589 1.11 christos rel->r_offset);
590 1.11 christos
591 1.11 christos if (_rtld_relocate_nonplt_object(obj, &ourrela,
592 1.11 christos dodebug) < 0)
593 1.11 christos ok = 0;
594 1.11 christos }
595 1.11 christos }
596 1.11 christos if (obj->rela != NULL) {
597 1.11 christos /* Process the non-PLT relocations. */
598 1.35 kleink const Elf_Rela *rela;
599 1.11 christos for (rela = obj->rela; rela < obj->relalim; ++rela) {
600 1.11 christos if (_rtld_relocate_nonplt_object(obj, rela,
601 1.11 christos dodebug) < 0)
602 1.11 christos ok = 0;
603 1.11 christos }
604 1.11 christos }
605 1.11 christos if (obj->textrel) { /* Re-protected the text segment. */
606 1.11 christos if (mprotect(obj->mapbase, obj->textsize,
607 1.11 christos PROT_READ | PROT_EXEC) == -1) {
608 1.11 christos _rtld_error("%s: Cannot write-protect text "
609 1.11 christos "segment: %s", obj->path, xstrerror(errno));
610 1.11 christos return -1;
611 1.11 christos }
612 1.11 christos }
613 1.11 christos /* Process the PLT relocations. */
614 1.11 christos if (obj->pltrel != NULL) {
615 1.11 christos const Elf_Rel *rel;
616 1.11 christos for (rel = obj->pltrel; rel < obj->pltrellim; ++rel) {
617 1.35 kleink Elf_Rela ourrela;
618 1.11 christos ourrela.r_info = rel->r_info;
619 1.11 christos ourrela.r_offset = rel->r_offset;
620 1.11 christos ourrela.r_addend =
621 1.11 christos *(Elf_Word *)(obj->relocbase +
622 1.11 christos rel->r_offset);
623 1.11 christos if (_rtld_relocate_plt_object(obj, &ourrela,
624 1.11 christos NULL, bind_now, dodebug) < 0)
625 1.11 christos ok = 0;
626 1.11 christos }
627 1.11 christos }
628 1.11 christos if (obj->pltrela != NULL) {
629 1.35 kleink const Elf_Rela *rela;
630 1.11 christos for (rela = obj->pltrela; rela < obj->pltrelalim;
631 1.11 christos ++rela) {
632 1.11 christos if (_rtld_relocate_plt_object(obj, rela,
633 1.11 christos NULL, bind_now, dodebug) < 0)
634 1.11 christos ok = 0;
635 1.11 christos }
636 1.11 christos }
637 1.11 christos if (!ok)
638 1.11 christos return -1;
639 1.11 christos
640 1.11 christos
641 1.11 christos /* Set some sanity-checking numbers in the Obj_Entry. */
642 1.11 christos obj->magic = RTLD_MAGIC;
643 1.11 christos obj->version = RTLD_VERSION;
644 1.11 christos
645 1.11 christos /* Fill in the dynamic linker entry points. */
646 1.11 christos obj->dlopen = _rtld_dlopen;
647 1.11 christos obj->dlsym = _rtld_dlsym;
648 1.11 christos obj->dlerror = _rtld_dlerror;
649 1.11 christos obj->dlclose = _rtld_dlclose;
650 1.25 scottb obj->dladdr = _rtld_dladdr;
651 1.1 cgd
652 1.11 christos /* Set the special PLTGOT entries. */
653 1.11 christos if (obj->pltgot != NULL) {
654 1.36 fvdl #if defined(__i386__) || defined(__m68k__) || defined(__x86_64__)
655 1.11 christos obj->pltgot[1] = (Elf_Addr) obj;
656 1.11 christos obj->pltgot[2] = (Elf_Addr) & _rtld_bind_start;
657 1.1 cgd #endif
658 1.1 cgd #if defined(__alpha__)
659 1.11 christos /*
660 1.11 christos * This function will be called to perform the
661 1.11 christos * relocation.
662 1.11 christos */
663 1.11 christos obj->pltgot[2] = (Elf_Addr) & _rtld_bind_start;
664 1.11 christos /* Identify this shared object */
665 1.11 christos obj->pltgot[3] = (Elf_Addr) obj;
666 1.2 mhitch #endif
667 1.2 mhitch #if defined(__mips__)
668 1.11 christos _rtld_relocate_mips_got(obj);
669 1.2 mhitch
670 1.11 christos obj->pltgot[0] = (Elf_Addr) & _rtld_bind_start;
671 1.11 christos /* XXX only if obj->pltgot[1] & 0x80000000 ?? */
672 1.11 christos obj->pltgot[1] |= (Elf_Addr) obj;
673 1.3 tsubai #endif
674 1.3 tsubai #if defined(__powerpc__)
675 1.11 christos _rtld_setup_powerpc_plt(obj);
676 1.9 pk #endif
677 1.9 pk #if defined(__sparc__)
678 1.31 mycroft #if defined(__arch64__) || defined(__sparc_v9__)
679 1.27 eeh /*
680 1.27 eeh * On sparc64 we got troubles.
681 1.27 eeh *
682 1.27 eeh * Instructions are 4 bytes long.
683 1.27 eeh * Elf[64]_Addr is 8 bytes long, so are our pltglot[]
684 1.27 eeh * array entries.
685 1.27 eeh * Each PLT entry jumps to PLT0 to enter the dynamic
686 1.27 eeh * linker.
687 1.27 eeh * Loading an arbitrary 64-bit pointer takes 6
688 1.27 eeh * instructions and 2 registers.
689 1.27 eeh *
690 1.27 eeh * Somehow we need to issue a save to get a new stack
691 1.27 eeh * frame, load the address of the dynamic linker, and
692 1.27 eeh * jump there, in 8 instructions or less.
693 1.27 eeh *
694 1.27 eeh * Oh, we need to fill out both PLT0 and PLT1.
695 1.27 eeh */
696 1.27 eeh {
697 1.31 mycroft Elf_Word *entry = (Elf_Word *)obj->pltgot;
698 1.31 mycroft extern void _rtld_install_plt __P((Elf_Word *,
699 1.27 eeh Elf_Addr));
700 1.27 eeh extern void _rtld_bind_start_0 __P((long,
701 1.27 eeh long));
702 1.27 eeh extern void _rtld_bind_start_1 __P((long,
703 1.27 eeh long));
704 1.27 eeh
705 1.27 eeh /* Install in entries 0 and 1 */
706 1.27 eeh _rtld_install_plt(&entry[0],
707 1.27 eeh (Elf_Addr)&_rtld_bind_start_0);
708 1.27 eeh _rtld_install_plt(&entry[8],
709 1.27 eeh (Elf_Addr)&_rtld_bind_start_1);
710 1.27 eeh
711 1.27 eeh /*
712 1.27 eeh * Install the object reference in first slot
713 1.27 eeh * of entry 2.
714 1.27 eeh */
715 1.30 eeh obj->pltgot[8] = (Elf_Addr) obj;
716 1.27 eeh }
717 1.27 eeh #else
718 1.11 christos /*
719 1.11 christos * PLTGOT is the PLT on the sparc.
720 1.11 christos * The first entry holds the call the dynamic linker.
721 1.13 pk * We construct a `call' sequence that transfers
722 1.11 christos * to `_rtld_bind_start()'.
723 1.11 christos * The second entry holds the object identification.
724 1.11 christos * Note: each PLT entry is three words long.
725 1.11 christos */
726 1.13 pk #define SAVE 0x9de3bfc0 /* i.e. `save %sp,-64,%sp' */
727 1.13 pk #define CALL 0x40000000
728 1.13 pk #define NOP 0x01000000
729 1.13 pk obj->pltgot[0] = SAVE;
730 1.13 pk obj->pltgot[1] = CALL |
731 1.11 christos ((Elf_Addr)&_rtld_bind_start -
732 1.13 pk (Elf_Addr)&obj->pltgot[1]) >> 2;
733 1.13 pk obj->pltgot[2] = NOP;
734 1.13 pk
735 1.11 christos obj->pltgot[3] = (Elf_Addr) obj;
736 1.28 matt #endif /* __arch64__ */
737 1.28 matt #endif /* __sparc__ */
738 1.21 matt #if defined(__vax__)
739 1.32 matt obj->pltgot[1] = (Elf_Addr) obj;
740 1.28 matt obj->pltgot[2] = (Elf_Addr) & _rtld_bind_start;
741 1.1 cgd #endif
742 1.11 christos }
743 1.1 cgd }
744 1.1 cgd
745 1.11 christos return 0;
746 1.1 cgd }
747