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Petr Machata64262602012-01-07 03:41:36 +01001/*
2 * This file is part of ltrace.
3 * Copyright (C) 2006,2010,2011,2012 Petr Machata, Red Hat Inc.
4 * Copyright (C) 2010 Zachary T Welch, CodeSourcery
5 * Copyright (C) 2010 Joe Damato
6 * Copyright (C) 1997,1998,2001,2004,2007,2008,2009 Juan Cespedes
7 * Copyright (C) 2006 Olaf Hering, SUSE Linux GmbH
8 * Copyright (C) 2006 Eric Vaitl, Cisco Systems, Inc.
9 * Copyright (C) 2006 Paul Gilliam, IBM Corporation
10 * Copyright (C) 2006 Ian Wienand
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
25 * 02110-1301 USA
26 */
27
Joe Damatof0bd98b2010-11-08 15:47:42 -080028#include "config.h"
Juan Cespedesd44c6b81998-09-25 14:48:42 +020029
Petr Machata157cc4d2012-04-04 19:00:34 +020030#include <assert.h>
Andrey Zonov9d878c92012-08-05 00:19:51 +040031#ifdef __linux__
Juan Cespedesd914a202004-11-10 00:15:33 +010032#include <endian.h>
Andrey Zonov9d878c92012-08-05 00:19:51 +040033#endif
Juan Cespedes96935a91997-08-09 23:45:39 +020034#include <errno.h>
Juan Cespedes96935a91997-08-09 23:45:39 +020035#include <fcntl.h>
Juan Cespedesd914a202004-11-10 00:15:33 +010036#include <gelf.h>
Zachary T Welchbfb26c72010-12-06 23:21:00 -080037#include <inttypes.h>
Petr Machata157cc4d2012-04-04 19:00:34 +020038#include <search.h>
Juan Cespedesd914a202004-11-10 00:15:33 +010039#include <stdint.h>
Petr Machatacc0e1e42012-04-25 13:42:07 +020040#include <stdio.h>
Juan Cespedesd914a202004-11-10 00:15:33 +010041#include <stdlib.h>
Juan Cespedes96935a91997-08-09 23:45:39 +020042#include <string.h>
Juan Cespedes5e01f651998-03-08 22:31:44 +010043#include <unistd.h>
Juan Cespedes96935a91997-08-09 23:45:39 +020044
Petr Machata64262602012-01-07 03:41:36 +010045#include "backend.h"
Petr Machataba1664b2012-04-28 14:59:05 +020046#include "filter.h"
47#include "library.h"
48#include "ltrace-elf.h"
49#include "proc.h"
50#include "debug.h"
51#include "options.h"
Joe Damatof0bd98b2010-11-08 15:47:42 -080052
Petr Machatae67635d2012-03-21 03:37:39 +010053#ifndef ARCH_HAVE_LTELF_DATA
54int
Petr Machatae0615ab2012-04-17 05:17:48 +020055arch_elf_init(struct ltelf *lte, struct library *lib)
Petr Machatae67635d2012-03-21 03:37:39 +010056{
57 return 0;
58}
Petr Machatac67a6e62012-03-28 02:39:49 +020059
60void
61arch_elf_destroy(struct ltelf *lte)
62{
63}
Petr Machatae67635d2012-03-21 03:37:39 +010064#endif
65
Petr Machata8bda1ee2012-09-26 01:52:23 +020066static int
Petr Machatae6523e62012-03-24 04:54:06 +010067default_elf_add_plt_entry(struct Process *proc, struct ltelf *lte,
Petr Machata1be22912012-03-27 03:11:33 +020068 const char *a_name, GElf_Rela *rela, size_t ndx,
Petr Machatae6523e62012-03-24 04:54:06 +010069 struct library_symbol **ret)
70{
71 char *name = strdup(a_name);
72 if (name == NULL) {
73 fail:
74 free(name);
75 return -1;
76 }
77
Petr Machata1be22912012-03-27 03:11:33 +020078 GElf_Addr addr = arch_plt_sym_val(lte, ndx, rela);
Petr Machatae6523e62012-03-24 04:54:06 +010079
80 struct library_symbol *libsym = malloc(sizeof(*libsym));
81 if (libsym == NULL)
82 goto fail;
83
Petr Machataea8eb9a2012-04-17 01:32:07 +020084 /* XXX The double cast should be removed when
Petr Machatabac2da52012-05-29 00:42:59 +020085 * arch_addr_t becomes integral type. */
86 arch_addr_t taddr = (arch_addr_t)
Petr Machataea8eb9a2012-04-17 01:32:07 +020087 (uintptr_t)(addr + lte->bias);
Petr Machatabb790602012-03-25 01:41:59 +010088
Petr Machatae8d90762012-04-15 04:28:31 +020089 if (library_symbol_init(libsym, taddr, name, 1, LS_TOPLT_EXEC) < 0) {
90 free(libsym);
91 goto fail;
92 }
93
Petr Machata0fa79042012-09-27 23:33:44 +020094 libsym->next = *ret;
Petr Machatae6523e62012-03-24 04:54:06 +010095 *ret = libsym;
96 return 0;
97}
98
99#ifndef ARCH_HAVE_ADD_PLT_ENTRY
100enum plt_status
101arch_elf_add_plt_entry(struct Process *proc, struct ltelf *lte,
Petr Machata1be22912012-03-27 03:11:33 +0200102 const char *a_name, GElf_Rela *rela, size_t ndx,
Petr Machatae6523e62012-03-24 04:54:06 +0100103 struct library_symbol **ret)
104{
105 return plt_default;
106}
107#endif
108
Petr Machatae67635d2012-03-21 03:37:39 +0100109Elf_Data *
110elf_loaddata(Elf_Scn *scn, GElf_Shdr *shdr)
Petr Machatafe1c1712010-10-27 16:57:34 +0200111{
112 Elf_Data *data = elf_getdata(scn, NULL);
113 if (data == NULL || elf_getdata(scn, data) != NULL
114 || data->d_off || data->d_size != shdr->sh_size)
115 return NULL;
116 return data;
117}
118
Petr Machatae67635d2012-03-21 03:37:39 +0100119static int
Petr Machataffd5aab2012-03-24 02:03:33 +0100120elf_get_section_if(struct ltelf *lte, Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr,
121 int (*predicate)(Elf_Scn *, GElf_Shdr *, void *data),
122 void *data)
Petr Machatafe1c1712010-10-27 16:57:34 +0200123{
124 int i;
125 for (i = 1; i < lte->ehdr.e_shnum; ++i) {
126 Elf_Scn *scn;
127 GElf_Shdr shdr;
128
129 scn = elf_getscn(lte->elf, i);
130 if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) {
131 debug(1, "Couldn't read section or header.");
Petr Machatae67635d2012-03-21 03:37:39 +0100132 return -1;
133 }
Petr Machataffd5aab2012-03-24 02:03:33 +0100134 if (predicate(scn, &shdr, data)) {
135 *tgt_sec = scn;
136 *tgt_shdr = shdr;
Petr Machatafe1c1712010-10-27 16:57:34 +0200137 return 0;
Petr Machataffd5aab2012-03-24 02:03:33 +0100138 }
Petr Machatafe1c1712010-10-27 16:57:34 +0200139 }
Petr Machatae67635d2012-03-21 03:37:39 +0100140 return -1;
Petr Machataffd5aab2012-03-24 02:03:33 +0100141
142}
143
144static int
145inside_p(Elf_Scn *scn, GElf_Shdr *shdr, void *data)
146{
147 GElf_Addr addr = *(GElf_Addr *)data;
148 return addr >= shdr->sh_addr
149 && addr < shdr->sh_addr + shdr->sh_size;
150}
151
152int
153elf_get_section_covering(struct ltelf *lte, GElf_Addr addr,
154 Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr)
155{
156 return elf_get_section_if(lte, tgt_sec, tgt_shdr,
157 &inside_p, &addr);
158}
159
160static int
161type_p(Elf_Scn *scn, GElf_Shdr *shdr, void *data)
162{
163 GElf_Word type = *(GElf_Word *)data;
164 return shdr->sh_type == type;
165}
166
167int
168elf_get_section_type(struct ltelf *lte, GElf_Word type,
169 Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr)
170{
171 return elf_get_section_if(lte, tgt_sec, tgt_shdr,
172 &type_p, &type);
Petr Machatae67635d2012-03-21 03:37:39 +0100173}
174
Petr Machata5b3e26a2012-04-30 20:53:22 +0200175struct section_named_data {
176 struct ltelf *lte;
177 const char *name;
178};
179
180static int
181name_p(Elf_Scn *scn, GElf_Shdr *shdr, void *d)
182{
183 struct section_named_data *data = d;
184 const char *name = elf_strptr(data->lte->elf,
185 data->lte->ehdr.e_shstrndx,
186 shdr->sh_name);
187 return strcmp(name, data->name) == 0;
188}
189
190int
191elf_get_section_named(struct ltelf *lte, const char *name,
192 Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr)
193{
194 struct section_named_data data = {
195 .lte = lte,
196 .name = name,
197 };
198 return elf_get_section_if(lte, tgt_sec, tgt_shdr,
199 &name_p, &data);
200}
201
Petr Machatae67635d2012-03-21 03:37:39 +0100202static int
Petr Machata3a01cd72012-04-30 20:50:20 +0200203need_data(Elf_Data *data, GElf_Xword offset, GElf_Xword size)
Petr Machatae67635d2012-03-21 03:37:39 +0100204{
205 assert(data != NULL);
206 if (data->d_size < size || offset > data->d_size - size) {
Petr Machataa82d3222012-05-01 01:04:27 +0200207 debug(1, "Not enough data to read %"PRId64"-byte value"
208 " at offset %"PRId64".", size, offset);
Petr Machatae67635d2012-03-21 03:37:39 +0100209 return -1;
210 }
Petr Machatafe1c1712010-10-27 16:57:34 +0200211 return 0;
212}
213
Petr Machatae67635d2012-03-21 03:37:39 +0100214#define DEF_READER(NAME, SIZE) \
215 int \
Petr Machata3a01cd72012-04-30 20:50:20 +0200216 NAME(Elf_Data *data, GElf_Xword offset, uint##SIZE##_t *retp) \
Petr Machatae67635d2012-03-21 03:37:39 +0100217 { \
218 if (!need_data(data, offset, SIZE / 8) < 0) \
219 return -1; \
220 \
Petr Machata6d8ccb22012-03-27 03:11:57 +0200221 if (data->d_buf == NULL) /* NODATA section */ { \
222 *retp = 0; \
223 return 0; \
224 } \
225 \
Petr Machatae67635d2012-03-21 03:37:39 +0100226 union { \
227 uint##SIZE##_t dst; \
228 char buf[0]; \
229 } u; \
230 memcpy(u.buf, data->d_buf + offset, sizeof(u.dst)); \
231 *retp = u.dst; \
232 return 0; \
Petr Machatafe1c1712010-10-27 16:57:34 +0200233 }
234
Petr Machatae67635d2012-03-21 03:37:39 +0100235DEF_READER(elf_read_u16, 16)
236DEF_READER(elf_read_u32, 32)
237DEF_READER(elf_read_u64, 64)
Petr Machatafe1c1712010-10-27 16:57:34 +0200238
Petr Machatae67635d2012-03-21 03:37:39 +0100239#undef DEF_READER
Petr Machatafe1c1712010-10-27 16:57:34 +0200240
Petr Machata1974dbc2011-08-19 18:58:01 +0200241int
Petr Machata02bd9ec2011-09-21 17:38:59 +0200242open_elf(struct ltelf *lte, const char *filename)
243{
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100244 lte->fd = open(filename, O_RDONLY);
245 if (lte->fd == -1)
Petr Machata1974dbc2011-08-19 18:58:01 +0200246 return 1;
Juan Cespedes96935a91997-08-09 23:45:39 +0200247
Petr Machata02bd9ec2011-09-21 17:38:59 +0200248 elf_version(EV_CURRENT);
249
Juan Cespedesd914a202004-11-10 00:15:33 +0100250#ifdef HAVE_ELF_C_READ_MMAP
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100251 lte->elf = elf_begin(lte->fd, ELF_C_READ_MMAP, NULL);
Juan Cespedes5c3fe062004-06-14 18:08:37 +0200252#else
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100253 lte->elf = elf_begin(lte->fd, ELF_C_READ, NULL);
Juan Cespedes5c3fe062004-06-14 18:08:37 +0200254#endif
Juan Cespedes1cd999a2001-07-03 00:46:04 +0200255
Petr Machatacc0e1e42012-04-25 13:42:07 +0200256 if (lte->elf == NULL || elf_kind(lte->elf) != ELF_K_ELF) {
257 fprintf(stderr, "\"%s\" is not an ELF file\n", filename);
258 exit(EXIT_FAILURE);
259 }
Juan Cespedes1cd999a2001-07-03 00:46:04 +0200260
Petr Machatacc0e1e42012-04-25 13:42:07 +0200261 if (gelf_getehdr(lte->elf, &lte->ehdr) == NULL) {
262 fprintf(stderr, "can't read ELF header of \"%s\": %s\n",
263 filename, elf_errmsg(-1));
264 exit(EXIT_FAILURE);
265 }
Juan Cespedes1cd999a2001-07-03 00:46:04 +0200266
Petr Machatacc0e1e42012-04-25 13:42:07 +0200267 if (lte->ehdr.e_type != ET_EXEC && lte->ehdr.e_type != ET_DYN) {
268 fprintf(stderr, "\"%s\" is neither an ELF executable"
269 " nor a shared library\n", filename);
270 exit(EXIT_FAILURE);
271 }
Juan Cespedes1cd999a2001-07-03 00:46:04 +0200272
Petr Machataddd96a32012-05-17 23:35:26 +0200273 if (1
274#ifdef LT_ELF_MACHINE
275 && (lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS
276 || lte->ehdr.e_machine != LT_ELF_MACHINE)
277#endif
Juan Cespedesd914a202004-11-10 00:15:33 +0100278#ifdef LT_ELF_MACHINE2
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100279 && (lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS2
280 || lte->ehdr.e_machine != LT_ELF_MACHINE2)
Juan Cespedesd914a202004-11-10 00:15:33 +0100281#endif
282#ifdef LT_ELF_MACHINE3
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100283 && (lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS3
284 || lte->ehdr.e_machine != LT_ELF_MACHINE3)
Juan Cespedesd914a202004-11-10 00:15:33 +0100285#endif
Petr Machatacc0e1e42012-04-25 13:42:07 +0200286 ) {
287 fprintf(stderr,
288 "\"%s\" is ELF from incompatible architecture\n",
289 filename);
290 exit(EXIT_FAILURE);
291 }
Juan Cespedesd914a202004-11-10 00:15:33 +0100292
Petr Machata02bd9ec2011-09-21 17:38:59 +0200293 return 0;
294}
295
Petr Machatacc0e1e42012-04-25 13:42:07 +0200296static void
297read_symbol_table(struct ltelf *lte, const char *filename,
298 Elf_Scn *scn, GElf_Shdr *shdr, const char *name,
299 Elf_Data **datap, size_t *countp, const char **strsp)
300{
301 *datap = elf_getdata(scn, NULL);
302 *countp = shdr->sh_size / shdr->sh_entsize;
303 if ((*datap == NULL || elf_getdata(scn, *datap) != NULL)
304 && options.static_filter != NULL) {
305 fprintf(stderr, "Couldn't get data of section"
306 " %s from \"%s\": %s\n",
307 name, filename, elf_errmsg(-1));
308 exit(EXIT_FAILURE);
309 }
310
311 scn = elf_getscn(lte->elf, shdr->sh_link);
312 GElf_Shdr shdr2;
313 if (scn == NULL || gelf_getshdr(scn, &shdr2) == NULL) {
314 fprintf(stderr, "Couldn't get header of section"
315 " #%d from \"%s\": %s\n",
316 shdr2.sh_link, filename, elf_errmsg(-1));
317 exit(EXIT_FAILURE);
318 }
319
320 Elf_Data *data = elf_getdata(scn, NULL);
321 if (data == NULL || elf_getdata(scn, data) != NULL
322 || shdr2.sh_size != data->d_size || data->d_off) {
323 fprintf(stderr, "Couldn't get data of section"
324 " #%d from \"%s\": %s\n",
325 shdr2.sh_link, filename, elf_errmsg(-1));
326 exit(EXIT_FAILURE);
327 }
328
329 *strsp = data->d_buf;
330}
331
Petr Machatae67635d2012-03-21 03:37:39 +0100332static int
333do_init_elf(struct ltelf *lte, const char *filename, GElf_Addr bias)
Petr Machata2b46cfc2012-02-18 11:17:29 +0100334{
Petr Machata02bd9ec2011-09-21 17:38:59 +0200335 int i;
336 GElf_Addr relplt_addr = 0;
Petr Machata2b46cfc2012-02-18 11:17:29 +0100337 GElf_Addr soname_offset = 0;
Petr Machata02bd9ec2011-09-21 17:38:59 +0200338
339 debug(DEBUG_FUNCTION, "do_init_elf(filename=%s)", filename);
340 debug(1, "Reading ELF from %s...", filename);
341
342 if (open_elf(lte, filename) < 0)
343 return -1;
344
Petr Machatab120fdf2012-03-21 05:05:46 +0100345 /* Find out the base address. */
Petr Machata29add4f2012-02-18 16:38:05 +0100346 {
Petr Machata2b46cfc2012-02-18 11:17:29 +0100347 GElf_Phdr phdr;
348 for (i = 0; gelf_getphdr (lte->elf, i, &phdr) != NULL; ++i) {
349 if (phdr.p_type == PT_LOAD) {
Petr Machata49275b02012-04-03 12:38:51 +0200350 lte->base_addr = phdr.p_vaddr + bias;
Petr Machata2b46cfc2012-02-18 11:17:29 +0100351 break;
352 }
353 }
354 }
355
Petr Machatab120fdf2012-03-21 05:05:46 +0100356 if (lte->base_addr == 0) {
357 fprintf(stderr, "Couldn't determine base address of %s\n",
358 filename);
359 return -1;
360 }
361
362 lte->bias = bias;
Petr Machata29add4f2012-02-18 16:38:05 +0100363 lte->entry_addr = lte->ehdr.e_entry + lte->bias;
Petr Machata2b46cfc2012-02-18 11:17:29 +0100364
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100365 for (i = 1; i < lte->ehdr.e_shnum; ++i) {
366 Elf_Scn *scn;
367 GElf_Shdr shdr;
368 const char *name;
Juan Cespedesd914a202004-11-10 00:15:33 +0100369
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100370 scn = elf_getscn(lte->elf, i);
Petr Machatacc0e1e42012-04-25 13:42:07 +0200371 if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) {
372 fprintf(stderr, "Couldn't get section #%d from"
373 " \"%s\": %s\n", i, filename, elf_errmsg(-1));
374 exit(EXIT_FAILURE);
375 }
Juan Cespedesd914a202004-11-10 00:15:33 +0100376
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100377 name = elf_strptr(lte->elf, lte->ehdr.e_shstrndx, shdr.sh_name);
Petr Machatacc0e1e42012-04-25 13:42:07 +0200378 if (name == NULL) {
379 fprintf(stderr, "Couldn't get name of section #%d from"
380 " \"%s\": %s\n", i, filename, elf_errmsg(-1));
381 exit(EXIT_FAILURE);
382 }
Juan Cespedesd914a202004-11-10 00:15:33 +0100383
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100384 if (shdr.sh_type == SHT_SYMTAB) {
Petr Machatacc0e1e42012-04-25 13:42:07 +0200385 read_symbol_table(lte, filename,
386 scn, &shdr, name, &lte->symtab,
387 &lte->symtab_count, &lte->strtab);
Juan Cespedesd914a202004-11-10 00:15:33 +0100388
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100389 } else if (shdr.sh_type == SHT_DYNSYM) {
Petr Machatacc0e1e42012-04-25 13:42:07 +0200390 read_symbol_table(lte, filename,
391 scn, &shdr, name, &lte->dynsym,
392 &lte->dynsym_count, &lte->dynstr);
Juan Cespedesd914a202004-11-10 00:15:33 +0100393
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100394 } else if (shdr.sh_type == SHT_DYNAMIC) {
395 Elf_Data *data;
396 size_t j;
Juan Cespedesd914a202004-11-10 00:15:33 +0100397
Joe Damato87f4f582010-11-08 15:47:36 -0800398 lte->dyn_addr = shdr.sh_addr;
399 lte->dyn_sz = shdr.sh_size;
400
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100401 data = elf_getdata(scn, NULL);
Petr Machatacc0e1e42012-04-25 13:42:07 +0200402 if (data == NULL || elf_getdata(scn, data) != NULL) {
403 fprintf(stderr, "Couldn't get .dynamic data"
404 " from \"%s\": %s\n",
405 filename, strerror(errno));
406 exit(EXIT_FAILURE);
407 }
Juan Cespedesd914a202004-11-10 00:15:33 +0100408
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100409 for (j = 0; j < shdr.sh_size / shdr.sh_entsize; ++j) {
410 GElf_Dyn dyn;
Juan Cespedesd914a202004-11-10 00:15:33 +0100411
Petr Machatacc0e1e42012-04-25 13:42:07 +0200412 if (gelf_getdyn(data, j, &dyn) == NULL) {
413 fprintf(stderr, "Couldn't get .dynamic"
414 " data from \"%s\": %s\n",
415 filename, strerror(errno));
416 exit(EXIT_FAILURE);
417 }
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100418 if (dyn.d_tag == DT_JMPREL)
419 relplt_addr = dyn.d_un.d_ptr;
420 else if (dyn.d_tag == DT_PLTRELSZ)
Petr Machatae67635d2012-03-21 03:37:39 +0100421 lte->relplt_size = dyn.d_un.d_val;
422 else if (dyn.d_tag == DT_SONAME)
Petr Machata2b46cfc2012-02-18 11:17:29 +0100423 soname_offset = dyn.d_un.d_val;
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100424 }
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100425 } else if (shdr.sh_type == SHT_PROGBITS
426 || shdr.sh_type == SHT_NOBITS) {
427 if (strcmp(name, ".plt") == 0) {
428 lte->plt_addr = shdr.sh_addr;
429 lte->plt_size = shdr.sh_size;
Petr Machatae67635d2012-03-21 03:37:39 +0100430 lte->plt_data = elf_loaddata(scn, &shdr);
431 if (lte->plt_data == NULL)
432 fprintf(stderr,
433 "Can't load .plt data\n");
Petr Machata18c801c2012-04-07 01:24:08 +0200434 lte->plt_flags = shdr.sh_flags;
Petr Machatab3f8fef2006-11-30 14:45:07 +0100435 }
436#ifdef ARCH_SUPPORTS_OPD
437 else if (strcmp(name, ".opd") == 0) {
Paul Gilliam3f1219f2006-04-24 18:25:38 +0200438 lte->opd_addr = (GElf_Addr *) (long) shdr.sh_addr;
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100439 lte->opd_size = shdr.sh_size;
440 lte->opd = elf_rawdata(scn, NULL);
441 }
Petr Machatab3f8fef2006-11-30 14:45:07 +0100442#endif
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100443 }
Juan Cespedesd914a202004-11-10 00:15:33 +0100444 }
445
Petr Machatacc0e1e42012-04-25 13:42:07 +0200446 if (lte->dynsym == NULL || lte->dynstr == NULL) {
447 fprintf(stderr, "Couldn't find .dynsym or .dynstr in \"%s\"\n",
448 filename);
449 exit(EXIT_FAILURE);
450 }
Juan Cespedesd914a202004-11-10 00:15:33 +0100451
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100452 if (!relplt_addr || !lte->plt_addr) {
453 debug(1, "%s has no PLT relocations", filename);
454 lte->relplt = NULL;
455 lte->relplt_count = 0;
Petr Machatae67635d2012-03-21 03:37:39 +0100456 } else if (lte->relplt_size == 0) {
Petr Machatafe1c1712010-10-27 16:57:34 +0200457 debug(1, "%s has unknown PLT size", filename);
458 lte->relplt = NULL;
459 lte->relplt_count = 0;
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100460 } else {
Petr Machatafe1c1712010-10-27 16:57:34 +0200461
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100462 for (i = 1; i < lte->ehdr.e_shnum; ++i) {
463 Elf_Scn *scn;
464 GElf_Shdr shdr;
465
466 scn = elf_getscn(lte->elf, i);
Petr Machatacc0e1e42012-04-25 13:42:07 +0200467 if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) {
468 fprintf(stderr, "Couldn't get section header"
469 " from \"%s\": %s\n",
470 filename, elf_errmsg(-1));
471 exit(EXIT_FAILURE);
472 }
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100473 if (shdr.sh_addr == relplt_addr
Petr Machatae67635d2012-03-21 03:37:39 +0100474 && shdr.sh_size == lte->relplt_size) {
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100475 lte->relplt = elf_getdata(scn, NULL);
476 lte->relplt_count =
477 shdr.sh_size / shdr.sh_entsize;
478 if (lte->relplt == NULL
Petr Machatacc0e1e42012-04-25 13:42:07 +0200479 || elf_getdata(scn, lte->relplt) != NULL) {
480 fprintf(stderr, "Couldn't get .rel*.plt"
481 " data from \"%s\": %s\n",
482 filename, elf_errmsg(-1));
483 exit(EXIT_FAILURE);
484 }
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100485 break;
486 }
487 }
488
Petr Machatacc0e1e42012-04-25 13:42:07 +0200489 if (i == lte->ehdr.e_shnum) {
490 fprintf(stderr,
491 "Couldn't find .rel*.plt section in \"%s\"\n",
492 filename);
493 exit(EXIT_FAILURE);
494 }
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100495
496 debug(1, "%s %zd PLT relocations", filename, lte->relplt_count);
497 }
Petr Machata2b46cfc2012-02-18 11:17:29 +0100498
499 if (soname_offset != 0)
500 lte->soname = lte->dynstr + soname_offset;
501
Petr Machata1974dbc2011-08-19 18:58:01 +0200502 return 0;
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100503}
504
Petr Machata2b46cfc2012-02-18 11:17:29 +0100505/* XXX temporarily non-static */
Joe Damato7a2bdf82010-11-08 15:47:41 -0800506void
Juan Cespedesf1350522008-12-16 18:19:58 +0100507do_close_elf(struct ltelf *lte) {
Juan Cespedescd8976d2009-05-14 13:47:58 +0200508 debug(DEBUG_FUNCTION, "do_close_elf()");
Petr Machata4d9a91c2012-03-24 04:55:03 +0100509 arch_elf_destroy(lte);
Ian Wienand2d45b1a2006-02-20 22:48:07 +0100510 elf_end(lte->elf);
511 close(lte->fd);
Juan Cespedes1cd999a2001-07-03 00:46:04 +0200512}
513
Edgar E. Iglesiasb5920d12012-09-27 12:07:35 +0200514#ifndef ARCH_HAVE_GET_SYMINFO
515int
516arch_get_sym_info(struct ltelf *lte, const char *filename,
517 size_t sym_index, GElf_Rela *rela, GElf_Sym *sym)
518{
519 int i = sym_index;
520 GElf_Rel rel;
521 void *ret;
522
523 if (lte->relplt->d_type == ELF_T_REL) {
524 ret = gelf_getrel(lte->relplt, i, &rel);
525 rela->r_offset = rel.r_offset;
526 rela->r_info = rel.r_info;
527 rela->r_addend = 0;
528 } else {
529 ret = gelf_getrela(lte->relplt, i, rela);
530 }
531
532 if (ret == NULL
533 || ELF64_R_SYM(rela->r_info) >= lte->dynsym_count
534 || gelf_getsym(lte->dynsym, ELF64_R_SYM(rela->r_info),
535 sym) == NULL) {
536 fprintf(stderr,
537 "Couldn't get relocation from \"%s\": %s\n",
538 filename, elf_errmsg(-1));
539 exit(EXIT_FAILURE);
540 }
541
542 return 0;
543}
544#endif
545
Petr Machatab5f80ac2012-04-04 01:46:18 +0200546static int
547populate_plt(struct Process *proc, const char *filename,
548 struct ltelf *lte, struct library *lib)
549{
550 size_t i;
551 for (i = 0; i < lte->relplt_count; ++i) {
Petr Machatab5f80ac2012-04-04 01:46:18 +0200552 GElf_Rela rela;
553 GElf_Sym sym;
Petr Machatab5f80ac2012-04-04 01:46:18 +0200554
Edgar E. Iglesiasb5920d12012-09-27 12:07:35 +0200555 if (arch_get_sym_info(lte, filename, i, &rela, &sym) < 0)
556 continue; /* Skip this entry. */
Petr Machatab5f80ac2012-04-04 01:46:18 +0200557
558 char const *name = lte->dynstr + sym.st_name;
559
560 if (!filter_matches_symbol(options.plt_filter, name, lib))
561 continue;
562
Petr Machata218c5ff2012-04-15 04:22:39 +0200563 struct library_symbol *libsym = NULL;
Petr Machatab5f80ac2012-04-04 01:46:18 +0200564 switch (arch_elf_add_plt_entry(proc, lte, name,
565 &rela, i, &libsym)) {
566 case plt_default:
567 if (default_elf_add_plt_entry(proc, lte, name,
568 &rela, i, &libsym) < 0)
Petr Machata8eb0d932012-04-17 05:18:18 +0200569 /* fall-through */
Petr Machatab5f80ac2012-04-04 01:46:18 +0200570 case plt_fail:
571 return -1;
Petr Machata8eb0d932012-04-17 05:18:18 +0200572 /* fall-through */
Petr Machatab5f80ac2012-04-04 01:46:18 +0200573 case plt_ok:
574 if (libsym != NULL)
575 library_add_symbol(lib, libsym);
576 }
577 }
578 return 0;
579}
580
Petr Machata157cc4d2012-04-04 19:00:34 +0200581/* When -x rules result in request to trace several aliases, we only
582 * want to add such symbol once. The only way that those symbols
583 * differ in is their name, e.g. in glibc you have __GI___libc_free,
584 * __cfree, __free, __libc_free, cfree and free all defined on the
585 * same address. So instead we keep this unique symbol struct for
586 * each address, and replace name in libsym with a shorter variant if
587 * we find it. */
588struct unique_symbol {
Petr Machatabac2da52012-05-29 00:42:59 +0200589 arch_addr_t addr;
Petr Machata157cc4d2012-04-04 19:00:34 +0200590 struct library_symbol *libsym;
591};
592
593static int
594unique_symbol_cmp(const void *key, const void *val)
595{
596 const struct unique_symbol *sym_key = key;
597 const struct unique_symbol *sym_val = val;
598 return sym_key->addr != sym_val->addr;
599}
600
Petr Machatada3edbf2012-04-04 02:20:21 +0200601static int
602populate_this_symtab(struct Process *proc, const char *filename,
603 struct ltelf *lte, struct library *lib,
604 Elf_Data *symtab, const char *strtab, size_t size)
605{
Petr Machata157cc4d2012-04-04 19:00:34 +0200606 /* Using sorted array would be arguably better, but this
607 * should be well enough for the number of symbols that we
608 * typically deal with. */
609 size_t num_symbols = 0;
610 struct unique_symbol *symbols = malloc(sizeof(*symbols) * size);
611 if (symbols == NULL) {
Petr Machatacc0e1e42012-04-25 13:42:07 +0200612 fprintf(stderr, "couldn't insert symbols for -x: %s\n",
613 strerror(errno));
Petr Machata157cc4d2012-04-04 19:00:34 +0200614 return -1;
615 }
616
Petr Machata40cc53b2012-04-07 01:25:38 +0200617 GElf_Word secflags[lte->ehdr.e_shnum];
Petr Machatada3edbf2012-04-04 02:20:21 +0200618 size_t i;
Petr Machata40cc53b2012-04-07 01:25:38 +0200619 for (i = 1; i < lte->ehdr.e_shnum; ++i) {
620 Elf_Scn *scn = elf_getscn(lte->elf, i);
621 if (scn == NULL)
622 continue;
623 GElf_Shdr shdr;
624 if (gelf_getshdr(scn, &shdr) == NULL)
625 continue;
626 secflags[i] = shdr.sh_flags;
627 }
628
629 size_t lib_len = strlen(lib->soname);
Petr Machatada3edbf2012-04-04 02:20:21 +0200630 for (i = 0; i < size; ++i) {
631 GElf_Sym sym;
Petr Machata074f68f2012-04-07 01:01:02 +0200632 if (gelf_getsym(symtab, i, &sym) == NULL) {
Petr Machatada3edbf2012-04-04 02:20:21 +0200633 fail:
Petr Machatacc0e1e42012-04-25 13:42:07 +0200634 fprintf(stderr,
635 "couldn't get symbol #%zd from %s: %s\n",
636 i, filename, elf_errmsg(-1));
Petr Machatada3edbf2012-04-04 02:20:21 +0200637 continue;
638 }
639
Petr Machata4de6b6b2012-04-04 14:06:09 +0200640 /* XXX support IFUNC as well. */
641 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC
Petr Machata6c1c0bb2012-05-18 16:49:34 +0200642 || sym.st_value == 0
643 || sym.st_shndx == STN_UNDEF)
Petr Machata4de6b6b2012-04-04 14:06:09 +0200644 continue;
645
Petr Machata2bbeac42012-04-30 20:48:34 +0200646 const char *orig_name = strtab + sym.st_name;
647 const char *version = strchr(orig_name, '@');
648 size_t len = version != NULL ? (assert(version > orig_name),
649 (size_t)(version - orig_name))
650 : strlen(orig_name);
651 char name[len + 1];
652 memcpy(name, orig_name, len);
653 name[len] = 0;
654
Petr Machatada3edbf2012-04-04 02:20:21 +0200655 if (!filter_matches_symbol(options.static_filter, name, lib))
656 continue;
Petr Machatada3edbf2012-04-04 02:20:21 +0200657
Petr Machatabac2da52012-05-29 00:42:59 +0200658 arch_addr_t addr = (arch_addr_t)
Petr Machataea8eb9a2012-04-17 01:32:07 +0200659 (uintptr_t)(sym.st_value + lte->bias);
Petr Machatabac2da52012-05-29 00:42:59 +0200660 arch_addr_t naddr;
Petr Machata40cc53b2012-04-07 01:25:38 +0200661
662 /* On arches that support OPD, the value of typical
663 * function symbol will be a pointer to .opd, but some
664 * will point directly to .text. We don't want to
665 * translate those. */
666 if (secflags[sym.st_shndx] & SHF_EXECINSTR) {
667 naddr = addr;
Petr Machatab1492df2012-04-30 21:01:40 +0200668 } else if (arch_translate_address(lte, addr, &naddr) < 0) {
Petr Machatacc0e1e42012-04-25 13:42:07 +0200669 fprintf(stderr,
670 "couldn't translate address of %s@%s: %s\n",
671 name, lib->soname, strerror(errno));
Petr Machatada3edbf2012-04-04 02:20:21 +0200672 continue;
673 }
Petr Machata40cc53b2012-04-07 01:25:38 +0200674
Petr Machata3840f682012-04-06 16:05:41 +0200675 char *full_name;
676 if (lib->type != LT_LIBTYPE_MAIN) {
677 full_name = malloc(strlen(name) + 1 + lib_len + 1);
678 if (full_name == NULL)
679 goto fail;
680 sprintf(full_name, "%s@%s", name, lib->soname);
681 } else {
682 full_name = strdup(name);
683 if (full_name == NULL)
684 goto fail;
685 }
Petr Machata4de6b6b2012-04-04 14:06:09 +0200686
Petr Machata157cc4d2012-04-04 19:00:34 +0200687 /* Look whether we already have a symbol for this
688 * address. If not, add this one. */
689 struct unique_symbol key = { naddr, NULL };
690 struct unique_symbol *unique
691 = lsearch(&key, symbols, &num_symbols,
692 sizeof(*symbols), &unique_symbol_cmp);
Petr Machatada3edbf2012-04-04 02:20:21 +0200693
Petr Machata157cc4d2012-04-04 19:00:34 +0200694 if (unique->libsym == NULL) {
695 struct library_symbol *libsym = malloc(sizeof(*libsym));
Petr Machatae8d90762012-04-15 04:28:31 +0200696 if (libsym == NULL
697 || library_symbol_init(libsym, naddr, full_name,
698 1, LS_TOPLT_NONE) < 0) {
Petr Machata157cc4d2012-04-04 19:00:34 +0200699 --num_symbols;
700 goto fail;
701 }
Petr Machata157cc4d2012-04-04 19:00:34 +0200702 unique->libsym = libsym;
703 unique->addr = naddr;
704
705 } else if (strlen(full_name) < strlen(unique->libsym->name)) {
706 library_symbol_set_name(unique->libsym, full_name, 1);
707
708 } else {
709 free(full_name);
710 }
Petr Machatada3edbf2012-04-04 02:20:21 +0200711 }
Petr Machata157cc4d2012-04-04 19:00:34 +0200712
713 for (i = 0; i < num_symbols; ++i) {
714 assert(symbols[i].libsym != NULL);
715 library_add_symbol(lib, symbols[i].libsym);
716 }
717
718 free(symbols);
719
Petr Machatada3edbf2012-04-04 02:20:21 +0200720 return 0;
721}
722
723static int
724populate_symtab(struct Process *proc, const char *filename,
725 struct ltelf *lte, struct library *lib)
726{
727 if (lte->symtab != NULL && lte->strtab != NULL)
728 return populate_this_symtab(proc, filename, lte, lib,
729 lte->symtab, lte->strtab,
730 lte->symtab_count);
731 else
732 return populate_this_symtab(proc, filename, lte, lib,
733 lte->dynsym, lte->dynstr,
734 lte->dynsym_count);
735}
736
Petr Machatab5f80ac2012-04-04 01:46:18 +0200737int
738ltelf_read_library(struct library *lib, struct Process *proc,
739 const char *filename, GElf_Addr bias)
Petr Machatae84fa002012-02-07 13:43:03 +0100740{
Petr Machata29add4f2012-02-18 16:38:05 +0100741 struct ltelf lte = {};
Petr Machatab120fdf2012-03-21 05:05:46 +0100742 if (do_init_elf(&lte, filename, bias) < 0)
Petr Machatab5f80ac2012-04-04 01:46:18 +0200743 return -1;
Petr Machatae0615ab2012-04-17 05:17:48 +0200744 if (arch_elf_init(&lte, lib) < 0) {
745 fprintf(stderr, "Backend initialization failed.\n");
746 return -1;
747 }
748
Petr Machatae67635d2012-03-21 03:37:39 +0100749 proc->e_machine = lte.ehdr.e_machine;
Petr Machata4d4e1b82012-05-30 11:08:39 -0400750 proc->e_class = lte.ehdr.e_ident[EI_CLASS];
Joe Damatof0bd98b2010-11-08 15:47:42 -0800751
Petr Machatab5f80ac2012-04-04 01:46:18 +0200752 int status = 0;
Petr Machatafc6ff182012-04-04 13:11:50 +0200753 if (lib == NULL)
754 goto fail;
755
756 /* Note that we set soname and pathname as soon as they are
757 * allocated, so in case of further errors, this get released
758 * when LIB is release, which should happen in the caller when
759 * we return error. */
760
761 if (lib->pathname == NULL) {
762 char *pathname = strdup(filename);
763 if (pathname == NULL)
764 goto fail;
Petr Machataf13afd52012-04-14 02:30:31 +0200765 library_set_pathname(lib, pathname, 1);
Joe Damatof0bd98b2010-11-08 15:47:42 -0800766 }
767
Petr Machata0b55b582012-04-02 00:38:46 +0200768 if (lte.soname != NULL) {
Petr Machatafc6ff182012-04-04 13:11:50 +0200769 char *soname = strdup(lte.soname);
770 if (soname == NULL)
771 goto fail;
772 library_set_soname(lib, soname, 1);
Petr Machata0b55b582012-04-02 00:38:46 +0200773 } else {
Petr Machatafc6ff182012-04-04 13:11:50 +0200774 const char *soname = rindex(lib->pathname, '/') + 1;
775 if (soname == NULL)
776 soname = lib->pathname;
777 library_set_soname(lib, soname, 0);
Petr Machata0b55b582012-04-02 00:38:46 +0200778 }
Joe Damatofa2aefc2010-10-30 19:56:50 -0700779
Petr Machataea8eb9a2012-04-17 01:32:07 +0200780 /* XXX The double cast should be removed when
Petr Machatabac2da52012-05-29 00:42:59 +0200781 * arch_addr_t becomes integral type. */
782 arch_addr_t entry = (arch_addr_t)(uintptr_t)lte.entry_addr;
Petr Machatab1492df2012-04-30 21:01:40 +0200783 if (arch_translate_address(&lte, entry, &entry) < 0)
Petr Machatab120fdf2012-03-21 05:05:46 +0100784 goto fail;
785
Petr Machataea8eb9a2012-04-17 01:32:07 +0200786 /* XXX The double cast should be removed when
Petr Machatabac2da52012-05-29 00:42:59 +0200787 * arch_addr_t becomes integral type. */
788 lib->base = (arch_addr_t)(uintptr_t)lte.base_addr;
Petr Machatab120fdf2012-03-21 05:05:46 +0100789 lib->entry = entry;
Petr Machataea8eb9a2012-04-17 01:32:07 +0200790 /* XXX The double cast should be removed when
Petr Machatabac2da52012-05-29 00:42:59 +0200791 * arch_addr_t becomes integral type. */
792 lib->dyn_addr = (arch_addr_t)(uintptr_t)lte.dyn_addr;
Ian Wienand9a2ad352006-02-20 22:44:45 +0100793
Petr Machatab5f80ac2012-04-04 01:46:18 +0200794 if (filter_matches_library(options.plt_filter, lib)
795 && populate_plt(proc, filename, &lte, lib) < 0)
796 goto fail;
Joe Damatoe2a8f572010-11-08 15:47:40 -0800797
Petr Machatada3edbf2012-04-04 02:20:21 +0200798 if (filter_matches_library(options.static_filter, lib)
799 && populate_symtab(proc, filename, &lte, lib) < 0)
800 goto fail;
801
Petr Machata2b46cfc2012-02-18 11:17:29 +0100802done:
803 do_close_elf(&lte);
Petr Machatab5f80ac2012-04-04 01:46:18 +0200804 return status;
Petr Machatafc6ff182012-04-04 13:11:50 +0200805
806fail:
807 status = -1;
808 goto done;
Petr Machata2b46cfc2012-02-18 11:17:29 +0100809}
Petr Machatae84fa002012-02-07 13:43:03 +0100810
Petr Machata2b46cfc2012-02-18 11:17:29 +0100811struct library *
812ltelf_read_main_binary(struct Process *proc, const char *path)
813{
Petr Machatab5f80ac2012-04-04 01:46:18 +0200814 struct library *lib = malloc(sizeof(*lib));
815 if (lib == NULL)
816 return NULL;
817 library_init(lib, LT_LIBTYPE_MAIN);
Petr Machatafc6ff182012-04-04 13:11:50 +0200818 library_set_pathname(lib, path, 0);
Petr Machatab5f80ac2012-04-04 01:46:18 +0200819
Petr Machatafc6ff182012-04-04 13:11:50 +0200820 /* There is a race between running the process and reading its
821 * binary for internal consumption. So open the binary from
822 * the /proc filesystem. XXX Note that there is similar race
823 * for libraries, but there we don't have a nice answer like
824 * that. Presumably we could read the DSOs from the process
825 * memory image, but that's not currently done. */
Petr Machata2b46cfc2012-02-18 11:17:29 +0100826 char *fname = pid2name(proc->pid);
Petr Machatab5f80ac2012-04-04 01:46:18 +0200827 if (ltelf_read_library(lib, proc, fname, 0) < 0) {
828 library_destroy(lib);
829 free(lib);
830 return NULL;
Petr Machata0b55b582012-04-02 00:38:46 +0200831 }
Petr Machatab5f80ac2012-04-04 01:46:18 +0200832
Petr Machata2b46cfc2012-02-18 11:17:29 +0100833 return lib;
Juan Cespedes96935a91997-08-09 23:45:39 +0200834}