1 /*-
2 * Copyright (c) 2010 Kai Wang
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 AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include "_libdwarf.h"
28
29 ELFTC_VCSID("$Id: libdwarf_reloc.c 3578 2017-09-14 02:21:28Z emaste $");
30
31 Dwarf_Unsigned
_dwarf_get_reloc_type(Dwarf_P_Debug dbg,int is64)32 _dwarf_get_reloc_type(Dwarf_P_Debug dbg, int is64)
33 {
34
35 assert(dbg != NULL);
36
37 switch (dbg->dbgp_isa) {
38 case DW_ISA_AARCH64:
39 return (is64 ? R_AARCH64_ABS64 : R_AARCH64_ABS32);
40 case DW_ISA_X86:
41 return (R_386_32);
42 case DW_ISA_X86_64:
43 return (is64 ? R_X86_64_64 : R_X86_64_32);
44 case DW_ISA_SPARC:
45 return (is64 ? R_SPARC_UA64 : R_SPARC_UA32);
46 case DW_ISA_PPC:
47 return (R_PPC_ADDR32);
48 case DW_ISA_ARM:
49 return (R_ARM_ABS32);
50 case DW_ISA_MIPS:
51 return (is64 ? R_MIPS_64 : R_MIPS_32);
52 case DW_ISA_RISCV:
53 return (is64 ? R_RISCV_64 : R_RISCV_32);
54 case DW_ISA_IA64:
55 return (is64 ? R_IA_64_DIR64LSB : R_IA_64_DIR32LSB);
56 default:
57 break;
58 }
59 return (0); /* NOT REACHED */
60 }
61
62 int
_dwarf_get_reloc_size(Dwarf_Debug dbg,Dwarf_Unsigned rel_type)63 _dwarf_get_reloc_size(Dwarf_Debug dbg, Dwarf_Unsigned rel_type)
64 {
65
66 switch (dbg->dbg_machine) {
67 case EM_NONE:
68 break;
69 case EM_AARCH64:
70 if (rel_type == R_AARCH64_ABS32)
71 return (4);
72 else if (rel_type == R_AARCH64_ABS64)
73 return (8);
74 break;
75 case EM_ARM:
76 if (rel_type == R_ARM_ABS32)
77 return (4);
78 break;
79 case EM_386:
80 case EM_IAMCU:
81 if (rel_type == R_386_32)
82 return (4);
83 break;
84 case EM_X86_64:
85 if (rel_type == R_X86_64_32)
86 return (4);
87 else if (rel_type == R_X86_64_64)
88 return (8);
89 break;
90 case EM_SPARC:
91 if (rel_type == R_SPARC_UA32)
92 return (4);
93 else if (rel_type == R_SPARC_UA64)
94 return (8);
95 break;
96 case EM_PPC:
97 if (rel_type == R_PPC_ADDR32)
98 return (4);
99 break;
100 case EM_MIPS:
101 if (rel_type == R_MIPS_32)
102 return (4);
103 else if (rel_type == R_MIPS_64)
104 return (8);
105 break;
106 case EM_RISCV:
107 if (rel_type == R_RISCV_32)
108 return (4);
109 else if (rel_type == R_RISCV_64)
110 return (8);
111 break;
112 case EM_IA_64:
113 if (rel_type == R_IA_64_SECREL32LSB)
114 return (4);
115 else if (rel_type == R_IA_64_DIR64LSB)
116 return (8);
117 break;
118 default:
119 break;
120 }
121
122 /* unknown relocation. */
123 return (0);
124 }
125
126 int
_dwarf_reloc_section_init(Dwarf_P_Debug dbg,Dwarf_Rel_Section * drsp,Dwarf_P_Section ref,Dwarf_Error * error)127 _dwarf_reloc_section_init(Dwarf_P_Debug dbg, Dwarf_Rel_Section *drsp,
128 Dwarf_P_Section ref, Dwarf_Error *error)
129 {
130 Dwarf_Rel_Section drs;
131 char name[128];
132 int pseudo;
133
134 assert(dbg != NULL && drsp != NULL && ref != NULL);
135
136 if ((drs = calloc(1, sizeof(struct _Dwarf_Rel_Section))) == NULL) {
137 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
138 return (DW_DLE_MEMORY);
139 }
140
141 drs->drs_ref = ref;
142
143 /*
144 * FIXME The logic here is most likely wrong. It should
145 * be the ISA that determines relocation type.
146 */
147 if (dbg->dbgp_flags & DW_DLC_SIZE_64)
148 drs->drs_addend = 1;
149 else
150 drs->drs_addend = 0;
151
152 if (dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS)
153 pseudo = 1;
154 else
155 pseudo = 0;
156
157 snprintf(name, sizeof(name), "%s%s",
158 drs->drs_addend ? ".rela" : ".rel", ref->ds_name);
159 if (_dwarf_section_init(dbg, &drs->drs_ds, name, pseudo, error) !=
160 DW_DLE_NONE) {
161 free(drs);
162 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
163 return (DW_DLE_MEMORY);
164 }
165
166 STAILQ_INIT(&drs->drs_dre);
167 STAILQ_INSERT_TAIL(&dbg->dbgp_drslist, drs, drs_next);
168 dbg->dbgp_drscnt++;
169 *drsp = drs;
170
171 return (DW_DLE_NONE);
172 }
173
174 void
_dwarf_reloc_section_free(Dwarf_P_Debug dbg,Dwarf_Rel_Section * drsp)175 _dwarf_reloc_section_free(Dwarf_P_Debug dbg, Dwarf_Rel_Section *drsp)
176 {
177 Dwarf_Rel_Section drs, tdrs;
178 Dwarf_Rel_Entry dre, tdre;
179
180 assert(dbg != NULL && drsp != NULL);
181
182 if (*drsp == NULL)
183 return;
184
185 STAILQ_FOREACH_SAFE(drs, &dbg->dbgp_drslist, drs_next, tdrs) {
186 if (drs != *drsp)
187 continue;
188 STAILQ_REMOVE(&dbg->dbgp_drslist, drs, _Dwarf_Rel_Section,
189 drs_next);
190 STAILQ_FOREACH_SAFE(dre, &drs->drs_dre, dre_next, tdre) {
191 STAILQ_REMOVE(&drs->drs_dre, dre, _Dwarf_Rel_Entry,
192 dre_next);
193 free(dre);
194 }
195 if ((dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) == 0)
196 _dwarf_section_free(dbg, &drs->drs_ds);
197 else {
198 if (drs->drs_ds->ds_name)
199 free(drs->drs_ds->ds_name);
200 free(drs->drs_ds);
201 }
202 free(drs);
203 *drsp = NULL;
204 dbg->dbgp_drscnt--;
205 break;
206 }
207 }
208
209 int
_dwarf_reloc_entry_add(Dwarf_P_Debug dbg,Dwarf_Rel_Section drs,Dwarf_P_Section ds,unsigned char type,unsigned char length,Dwarf_Unsigned offset,Dwarf_Unsigned symndx,Dwarf_Unsigned addend,const char * secname,Dwarf_Error * error)210 _dwarf_reloc_entry_add(Dwarf_P_Debug dbg, Dwarf_Rel_Section drs,
211 Dwarf_P_Section ds, unsigned char type, unsigned char length,
212 Dwarf_Unsigned offset, Dwarf_Unsigned symndx, Dwarf_Unsigned addend,
213 const char *secname, Dwarf_Error *error)
214 {
215 Dwarf_Rel_Entry dre;
216 Dwarf_Unsigned reloff;
217 int ret;
218
219 assert(drs != NULL);
220 assert(offset <= ds->ds_size);
221 reloff = offset;
222
223 /*
224 * If the DW_DLC_SYMBOLIC_RELOCATIONS flag is set or ElfXX_Rel
225 * is used instead of ELfXX_Rela, we need to write the addend
226 * in the storage unit to be relocated. Otherwise write 0 in the
227 * storage unit and the addend will be written into relocation
228 * section later.
229 */
230 if ((dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) ||
231 drs->drs_addend == 0)
232 ret = dbg->write_alloc(&ds->ds_data, &ds->ds_cap, &offset,
233 addend, length, error);
234 else
235 ret = dbg->write_alloc(&ds->ds_data, &ds->ds_cap, &offset,
236 0, length, error);
237 if (ret != DW_DLE_NONE)
238 return (ret);
239 if (offset > ds->ds_size)
240 ds->ds_size = offset;
241
242 if ((dre = calloc(1, sizeof(struct _Dwarf_Rel_Entry))) == NULL) {
243 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
244 return (DW_DLE_MEMORY);
245 }
246 STAILQ_INSERT_TAIL(&drs->drs_dre, dre, dre_next);
247 dre->dre_type = type;
248 dre->dre_length = length;
249 dre->dre_offset = reloff;
250 dre->dre_symndx = symndx;
251 dre->dre_addend = addend;
252 dre->dre_secname = secname;
253 drs->drs_drecnt++;
254
255 return (DW_DLE_NONE);
256 }
257
258 int
_dwarf_reloc_entry_add_pair(Dwarf_P_Debug dbg,Dwarf_Rel_Section drs,Dwarf_P_Section ds,unsigned char length,Dwarf_Unsigned offset,Dwarf_Unsigned symndx,Dwarf_Unsigned esymndx,Dwarf_Unsigned symoff,Dwarf_Unsigned esymoff,Dwarf_Error * error)259 _dwarf_reloc_entry_add_pair(Dwarf_P_Debug dbg, Dwarf_Rel_Section drs,
260 Dwarf_P_Section ds, unsigned char length, Dwarf_Unsigned offset,
261 Dwarf_Unsigned symndx, Dwarf_Unsigned esymndx, Dwarf_Unsigned symoff,
262 Dwarf_Unsigned esymoff, Dwarf_Error *error)
263 {
264 Dwarf_Rel_Entry dre;
265 Dwarf_Unsigned reloff;
266 int ret;
267
268 assert(drs != NULL);
269 assert(offset <= ds->ds_size);
270 assert(dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS);
271 reloff = offset;
272
273 /* Write net offset into section stream. */
274 ret = dbg->write_alloc(&ds->ds_data, &ds->ds_cap, &offset,
275 esymoff - symoff, length, error);
276 if (ret != DW_DLE_NONE)
277 return (ret);
278 if (offset > ds->ds_size)
279 ds->ds_size = offset;
280
281 if ((dre = calloc(2, sizeof(struct _Dwarf_Rel_Entry))) == NULL) {
282 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
283 return (DW_DLE_MEMORY);
284 }
285 STAILQ_INSERT_TAIL(&drs->drs_dre, &dre[0], dre_next);
286 STAILQ_INSERT_TAIL(&drs->drs_dre, &dre[1], dre_next);
287 dre[0].dre_type = dwarf_drt_first_of_length_pair;
288 dre[0].dre_length = length;
289 dre[0].dre_offset = reloff;
290 dre[0].dre_symndx = symndx;
291 dre[0].dre_addend = 0;
292 dre[0].dre_secname = NULL;
293 dre[1].dre_type = dwarf_drt_second_of_length_pair;
294 dre[1].dre_length = length;
295 dre[1].dre_offset = reloff;
296 dre[1].dre_symndx = esymndx;
297 dre[1].dre_addend = 0;
298 dre[1].dre_secname = NULL;
299 drs->drs_drecnt += 2;
300
301 return (DW_DLE_NONE);
302 }
303
304 int
_dwarf_reloc_section_finalize(Dwarf_P_Debug dbg,Dwarf_Rel_Section drs,Dwarf_Error * error)305 _dwarf_reloc_section_finalize(Dwarf_P_Debug dbg, Dwarf_Rel_Section drs,
306 Dwarf_Error *error)
307 {
308 Dwarf_P_Section ds;
309 Dwarf_Unsigned unit;
310 int ret, size;
311
312 assert(dbg != NULL && drs != NULL && drs->drs_ds != NULL &&
313 drs->drs_ref != NULL);
314
315 ds = drs->drs_ds;
316
317 /*
318 * Calculate the size (in bytes) of the relocation section.
319 */
320 if (dbg->dbgp_flags & DW_DLC_SIZE_64)
321 unit = drs->drs_addend ? sizeof(Elf64_Rela) : sizeof(Elf64_Rel);
322 else
323 unit = drs->drs_addend ? sizeof(Elf32_Rela) : sizeof(Elf32_Rel);
324 assert(ds->ds_size == 0);
325 size = drs->drs_drecnt * unit;
326
327 /*
328 * Discard this relocation section if there is no entry in it.
329 */
330 if (size == 0) {
331 _dwarf_reloc_section_free(dbg, &drs);
332 return (DW_DLE_NONE);
333 }
334
335 /*
336 * If we are under stream mode, realloc the section data block to
337 * this size.
338 */
339 if ((dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) == 0) {
340 ds->ds_cap = size;
341 if ((ds->ds_data = realloc(ds->ds_data, (size_t) ds->ds_cap)) ==
342 NULL) {
343 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
344 return (DW_DLE_MEMORY);
345 }
346 }
347
348 /*
349 * Notify the application the creation of this relocation section.
350 * Note that the section link here should point to the .symtab
351 * section, we set it to 0 since we have no way to know .symtab
352 * section index.
353 */
354 ret = _dwarf_pro_callback(dbg, ds->ds_name, size,
355 drs->drs_addend ? SHT_RELA : SHT_REL, 0, 0, drs->drs_ref->ds_ndx,
356 &ds->ds_symndx, NULL);
357 if (ret < 0) {
358 DWARF_SET_ERROR(dbg, error, DW_DLE_ELF_SECT_ERR);
359 return (DW_DLE_ELF_SECT_ERR);
360 }
361 ds->ds_ndx = ret;
362
363 return (DW_DLE_NONE);
364 }
365
366 int
_dwarf_reloc_section_gen(Dwarf_P_Debug dbg,Dwarf_Rel_Section drs,Dwarf_Error * error)367 _dwarf_reloc_section_gen(Dwarf_P_Debug dbg, Dwarf_Rel_Section drs,
368 Dwarf_Error *error)
369 {
370 Dwarf_Rel_Entry dre;
371 Dwarf_P_Section ds;
372 Dwarf_Unsigned type;
373 int ret;
374
375 assert((dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) == 0);
376 assert(drs->drs_ds != NULL && drs->drs_ds->ds_size == 0);
377 assert(!STAILQ_EMPTY(&drs->drs_dre));
378 ds = drs->drs_ds;
379
380 STAILQ_FOREACH(dre, &drs->drs_dre, dre_next) {
381 assert(dre->dre_length == 4 || dre->dre_length == 8);
382 type = _dwarf_get_reloc_type(dbg, dre->dre_length == 8);
383 if (dbg->dbgp_flags & DW_DLC_SIZE_64) {
384 /* Write r_offset (8 bytes) */
385 ret = dbg->write_alloc(&ds->ds_data, &ds->ds_cap,
386 &ds->ds_size, dre->dre_offset, 8, error);
387 if (ret != DW_DLE_NONE)
388 return (ret);
389 /* Write r_info (8 bytes) */
390 ret = dbg->write_alloc(&ds->ds_data, &ds->ds_cap,
391 &ds->ds_size, ELF64_R_INFO(dre->dre_symndx, type),
392 8, error);
393 if (ret != DW_DLE_NONE)
394 return (ret);
395 /* Write r_addend (8 bytes) */
396 if (drs->drs_addend) {
397 ret = dbg->write_alloc(&ds->ds_data,
398 &ds->ds_cap, &ds->ds_size, dre->dre_addend,
399 8, error);
400 if (ret != DW_DLE_NONE)
401 return (ret);
402 }
403 } else {
404 /* Write r_offset (4 bytes) */
405 ret = dbg->write_alloc(&ds->ds_data, &ds->ds_cap,
406 &ds->ds_size, dre->dre_offset, 4, error);
407 if (ret != DW_DLE_NONE)
408 return (ret);
409 /* Write r_info (4 bytes) */
410 ret = dbg->write_alloc(&ds->ds_data, &ds->ds_cap,
411 &ds->ds_size, ELF32_R_INFO(dre->dre_symndx, type),
412 4, error);
413 if (ret != DW_DLE_NONE)
414 return (ret);
415 /* Write r_addend (4 bytes) */
416 if (drs->drs_addend) {
417 ret = dbg->write_alloc(&ds->ds_data,
418 &ds->ds_cap, &ds->ds_size, dre->dre_addend,
419 4, error);
420 if (ret != DW_DLE_NONE)
421 return (ret);
422 }
423 }
424 }
425 assert(ds->ds_size == ds->ds_cap);
426
427 return (DW_DLE_NONE);
428 }
429
430 int
_dwarf_reloc_gen(Dwarf_P_Debug dbg,Dwarf_Error * error)431 _dwarf_reloc_gen(Dwarf_P_Debug dbg, Dwarf_Error *error)
432 {
433 Dwarf_Rel_Section drs;
434 Dwarf_Rel_Entry dre;
435 Dwarf_P_Section ds;
436 int ret;
437
438 STAILQ_FOREACH(drs, &dbg->dbgp_drslist, drs_next) {
439 /*
440 * Update relocation entries: translate any section name
441 * reference to section symbol index.
442 */
443 STAILQ_FOREACH(dre, &drs->drs_dre, dre_next) {
444 if (dre->dre_secname == NULL)
445 continue;
446 ds = _dwarf_pro_find_section(dbg, dre->dre_secname);
447 assert(ds != NULL && ds->ds_symndx != 0);
448 dre->dre_symndx = ds->ds_symndx;
449 }
450
451 /*
452 * Generate ELF relocation section if we are under stream
453 * mode.
454 */
455 if ((dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) == 0) {
456 ret = _dwarf_reloc_section_gen(dbg, drs, error);
457 if (ret != DW_DLE_NONE)
458 return (ret);
459 }
460 }
461
462 return (DW_DLE_NONE);
463 }
464
465 void
_dwarf_reloc_cleanup(Dwarf_P_Debug dbg)466 _dwarf_reloc_cleanup(Dwarf_P_Debug dbg)
467 {
468 Dwarf_Rel_Section drs, tdrs;
469 Dwarf_Rel_Entry dre, tdre;
470
471 assert(dbg != NULL && dbg->dbg_mode == DW_DLC_WRITE);
472
473 STAILQ_FOREACH_SAFE(drs, &dbg->dbgp_drslist, drs_next, tdrs) {
474 STAILQ_REMOVE(&dbg->dbgp_drslist, drs, _Dwarf_Rel_Section,
475 drs_next);
476 free(drs->drs_drd);
477 STAILQ_FOREACH_SAFE(dre, &drs->drs_dre, dre_next, tdre) {
478 STAILQ_REMOVE(&drs->drs_dre, dre, _Dwarf_Rel_Entry,
479 dre_next);
480 free(dre);
481 }
482 if (dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) {
483 if (drs->drs_ds) {
484 if (drs->drs_ds->ds_name)
485 free(drs->drs_ds->ds_name);
486 free(drs->drs_ds);
487 }
488 }
489 free(drs);
490 }
491 dbg->dbgp_drscnt = 0;
492 dbg->dbgp_drspos = NULL;
493 }
494