2 * Copyright (c) 2010 Kai Wang
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
27 #include "_libdwarf.h"
29 ELFTC_VCSID("$Id: libdwarf_reloc.c 3578 2017-09-14 02:21:28Z emaste $");
32 _dwarf_get_reloc_type(Dwarf_P_Debug dbg, int is64)
37 switch (dbg->dbgp_isa) {
39 return (is64 ? R_AARCH64_ABS64 : R_AARCH64_ABS32);
43 return (is64 ? R_X86_64_64 : R_X86_64_32);
45 return (is64 ? R_SPARC_UA64 : R_SPARC_UA32);
47 return (R_PPC_ADDR32);
51 return (is64 ? R_MIPS_64 : R_MIPS_32);
53 return (is64 ? R_RISCV_64 : R_RISCV_32);
55 return (is64 ? R_IA_64_DIR64LSB : R_IA_64_DIR32LSB);
59 return (0); /* NOT REACHED */
63 _dwarf_get_reloc_size(Dwarf_Debug dbg, Dwarf_Unsigned rel_type)
66 switch (dbg->dbg_machine) {
70 if (rel_type == R_AARCH64_ABS32)
72 else if (rel_type == R_AARCH64_ABS64)
76 if (rel_type == R_ARM_ABS32)
81 if (rel_type == R_386_32)
85 if (rel_type == R_X86_64_32)
87 else if (rel_type == R_X86_64_64)
91 if (rel_type == R_SPARC_UA32)
93 else if (rel_type == R_SPARC_UA64)
97 if (rel_type == R_PPC_ADDR32)
101 if (rel_type == R_MIPS_32)
103 else if (rel_type == R_MIPS_64)
107 if (rel_type == R_RISCV_32)
109 else if (rel_type == R_RISCV_64)
113 if (rel_type == R_IA_64_SECREL32LSB)
115 else if (rel_type == R_IA_64_DIR64LSB)
122 /* unknown relocation. */
127 _dwarf_reloc_section_init(Dwarf_P_Debug dbg, Dwarf_Rel_Section *drsp,
128 Dwarf_P_Section ref, Dwarf_Error *error)
130 Dwarf_Rel_Section drs;
134 assert(dbg != NULL && drsp != NULL && ref != NULL);
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);
144 * FIXME The logic here is most likely wrong. It should
145 * be the ISA that determines relocation type.
147 if (dbg->dbgp_flags & DW_DLC_SIZE_64)
152 if (dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS)
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) !=
162 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
163 return (DW_DLE_MEMORY);
166 STAILQ_INIT(&drs->drs_dre);
167 STAILQ_INSERT_TAIL(&dbg->dbgp_drslist, drs, drs_next);
171 return (DW_DLE_NONE);
175 _dwarf_reloc_section_free(Dwarf_P_Debug dbg, Dwarf_Rel_Section *drsp)
177 Dwarf_Rel_Section drs, tdrs;
178 Dwarf_Rel_Entry dre, tdre;
180 assert(dbg != NULL && drsp != NULL);
185 STAILQ_FOREACH_SAFE(drs, &dbg->dbgp_drslist, drs_next, tdrs) {
188 STAILQ_REMOVE(&dbg->dbgp_drslist, drs, _Dwarf_Rel_Section,
190 STAILQ_FOREACH_SAFE(dre, &drs->drs_dre, dre_next, tdre) {
191 STAILQ_REMOVE(&drs->drs_dre, dre, _Dwarf_Rel_Entry,
195 if ((dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) == 0)
196 _dwarf_section_free(dbg, &drs->drs_ds);
198 if (drs->drs_ds->ds_name)
199 free(drs->drs_ds->ds_name);
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)
216 Dwarf_Unsigned reloff;
220 assert(offset <= ds->ds_size);
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
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);
235 ret = dbg->write_alloc(&ds->ds_data, &ds->ds_cap, &offset,
237 if (ret != DW_DLE_NONE)
239 if (offset > ds->ds_size)
240 ds->ds_size = offset;
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);
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;
255 return (DW_DLE_NONE);
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)
265 Dwarf_Unsigned reloff;
269 assert(offset <= ds->ds_size);
270 assert(dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS);
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)
278 if (offset > ds->ds_size)
279 ds->ds_size = offset;
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);
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;
301 return (DW_DLE_NONE);
305 _dwarf_reloc_section_finalize(Dwarf_P_Debug dbg, Dwarf_Rel_Section drs,
312 assert(dbg != NULL && drs != NULL && drs->drs_ds != NULL &&
313 drs->drs_ref != NULL);
318 * Calculate the size (in bytes) of the relocation section.
320 if (dbg->dbgp_flags & DW_DLC_SIZE_64)
321 unit = drs->drs_addend ? sizeof(Elf64_Rela) : sizeof(Elf64_Rel);
323 unit = drs->drs_addend ? sizeof(Elf32_Rela) : sizeof(Elf32_Rel);
324 assert(ds->ds_size == 0);
325 size = drs->drs_drecnt * unit;
328 * Discard this relocation section if there is no entry in it.
331 _dwarf_reloc_section_free(dbg, &drs);
332 return (DW_DLE_NONE);
336 * If we are under stream mode, realloc the section data block to
339 if ((dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) == 0) {
341 if ((ds->ds_data = realloc(ds->ds_data, (size_t) ds->ds_cap)) ==
343 DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
344 return (DW_DLE_MEMORY);
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
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);
358 DWARF_SET_ERROR(dbg, error, DW_DLE_ELF_SECT_ERR);
359 return (DW_DLE_ELF_SECT_ERR);
363 return (DW_DLE_NONE);
367 _dwarf_reloc_section_gen(Dwarf_P_Debug dbg, Dwarf_Rel_Section drs,
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));
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)
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),
393 if (ret != DW_DLE_NONE)
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,
400 if (ret != DW_DLE_NONE)
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)
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),
413 if (ret != DW_DLE_NONE)
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,
420 if (ret != DW_DLE_NONE)
425 assert(ds->ds_size == ds->ds_cap);
427 return (DW_DLE_NONE);
431 _dwarf_reloc_gen(Dwarf_P_Debug dbg, Dwarf_Error *error)
433 Dwarf_Rel_Section drs;
438 STAILQ_FOREACH(drs, &dbg->dbgp_drslist, drs_next) {
440 * Update relocation entries: translate any section name
441 * reference to section symbol index.
443 STAILQ_FOREACH(dre, &drs->drs_dre, dre_next) {
444 if (dre->dre_secname == NULL)
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;
452 * Generate ELF relocation section if we are under stream
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)
462 return (DW_DLE_NONE);
466 _dwarf_reloc_cleanup(Dwarf_P_Debug dbg)
468 Dwarf_Rel_Section drs, tdrs;
469 Dwarf_Rel_Entry dre, tdre;
471 assert(dbg != NULL && dbg->dbg_mode == DW_DLC_WRITE);
473 STAILQ_FOREACH_SAFE(drs, &dbg->dbgp_drslist, drs_next, tdrs) {
474 STAILQ_REMOVE(&dbg->dbgp_drslist, drs, _Dwarf_Rel_Section,
477 STAILQ_FOREACH_SAFE(dre, &drs->drs_dre, dre_next, tdre) {
478 STAILQ_REMOVE(&drs->drs_dre, dre, _Dwarf_Rel_Entry,
482 if (dbg->dbgp_flags & DW_DLC_SYMBOLIC_RELOCATIONS) {
484 if (drs->drs_ds->ds_name)
485 free(drs->drs_ds->ds_name);
491 dbg->dbgp_drscnt = 0;
492 dbg->dbgp_drspos = NULL;