1 /*
2 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include <unistd.h>
26 #include <search.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <db.h>
30 #include <fcntl.h>
31 #include "symtab.h"
32 #include "salibelf.h"
33
34
35 // ----------------------------------------------------
36 // functions for symbol lookups
37 // ----------------------------------------------------
38
39 struct elf_section {
40 ELF_SHDR *c_shdr;
41 void *c_data;
42 };
43
44 struct elf_symbol {
45 char *name;
46 uintptr_t offset;
47 uintptr_t size;
48 };
49
50 typedef struct symtab {
51 char *strs;
52 size_t num_symbols;
53 struct elf_symbol *symbols;
54 DB* hash_table;
55 } symtab_t;
56
57 // read symbol table from given fd.
58 struct symtab* build_symtab(int fd) {
59 ELF_EHDR ehdr;
60 struct symtab* symtab = NULL;
61
62 // Reading of elf header
63 struct elf_section *scn_cache = NULL;
64 int cnt = 0;
65 ELF_SHDR* shbuf = NULL;
66 ELF_SHDR* cursct = NULL;
67 ELF_PHDR* phbuf = NULL;
68 int symtab_found = 0;
69 int dynsym_found = 0;
70 uint32_t symsection = SHT_SYMTAB;
71
72 uintptr_t baseaddr = (uintptr_t)-1;
73
74 lseek(fd, (off_t)0L, SEEK_SET);
75 if (! read_elf_header(fd, &ehdr)) {
76 // not an elf
77 return NULL;
78 }
159
160 // copy symbols info our symtab and enter them info the hash table
161 for (j = 0; j < n; j++, syms++) {
162 DBT key, value;
163 char *sym_name = symtab->strs + syms->st_name;
164
165 // skip non-object and non-function symbols
166 int st_type = ELF_ST_TYPE(syms->st_info);
167 if ( st_type != STT_FUNC && st_type != STT_OBJECT)
168 continue;
169 // skip empty strings and undefined symbols
170 if (*sym_name == '\0' || syms->st_shndx == SHN_UNDEF) continue;
171
172 symtab->symbols[j].name = sym_name;
173 symtab->symbols[j].offset = syms->st_value - baseaddr;
174 symtab->symbols[j].size = syms->st_size;
175
176 key.data = sym_name;
177 key.size = strlen(sym_name) + 1;
178 value.data = &(symtab->symbols[j]);
179 value.size = sizeof(void *);
180 (*symtab->hash_table->put)(symtab->hash_table, &key, &value, 0);
181 }
182 }
183 }
184 goto quit;
185
186 bad:
187 destroy_symtab(symtab);
188 symtab = NULL;
189
190 quit:
191 if (shbuf) free(shbuf);
192 if (phbuf) free(phbuf);
193 if (scn_cache) {
194 for (cnt = 0; cnt < ehdr.e_shnum; cnt++) {
195 if (scn_cache[cnt].c_data != NULL) {
196 free(scn_cache[cnt].c_data);
197 }
198 }
199 free(scn_cache);
200 }
201 return symtab;
202 }
203
204 void destroy_symtab(struct symtab* symtab) {
205 if (!symtab) return;
206 if (symtab->strs) free(symtab->strs);
207 if (symtab->symbols) free(symtab->symbols);
208 if (symtab->hash_table) {
209 (*symtab->hash_table->close)(symtab->hash_table);
210 }
211 free(symtab);
212 }
213
214 uintptr_t search_symbol(struct symtab* symtab, uintptr_t base,
215 const char *sym_name, int *sym_size) {
216 DBT key, value;
217 int ret;
218
219 // library does not have symbol table
220 if (!symtab || !symtab->hash_table)
221 return 0;
222
223 key.data = (char*)(uintptr_t)sym_name;
224 key.size = strlen(sym_name) + 1;
225 ret = (*symtab->hash_table->get)(symtab->hash_table, &key, &value, 0);
226 if (ret == 0) {
227 struct elf_symbol *sym = value.data;
228 uintptr_t rslt = (uintptr_t) ((char*)base + sym->offset);
229 if (sym_size) *sym_size = sym->size;
230 return rslt;
231 }
232
233 return 0;
234 }
235
236 const char* nearest_symbol(struct symtab* symtab, uintptr_t offset,
237 uintptr_t* poffset) {
238 int n = 0;
239 if (!symtab) return NULL;
240 for (; n < symtab->num_symbols; n++) {
241 struct elf_symbol* sym = &(symtab->symbols[n]);
242 if (sym->name != NULL &&
243 offset >= sym->offset && offset < sym->offset + sym->size) {
244 if (poffset) *poffset = (offset - sym->offset);
245 return sym->name;
246 }
247 }
248 return NULL;
249 }
|
1 /*
2 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include <unistd.h>
26 #include <search.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <db.h>
30 #include <fcntl.h>
31
32 #include "libproc_impl.h"
33 #include "symtab.h"
34 #ifndef __APPLE__
35 #include "salibelf.h"
36 #endif // __APPLE__
37
38
39 // ----------------------------------------------------
40 // functions for symbol lookups
41 // ----------------------------------------------------
42
43 typedef struct symtab_symbol {
44 char *name; // name like __ZThread_...
45 uintptr_t offset; // to loaded address
46 uintptr_t size; // size strlen
47 } symtab_symbol;
48
49 typedef struct symtab {
50 char *strs; // all symbols "__symbol1__'\0'__symbol2__...."
51 size_t num_symbols;
52 DB* hash_table;
53 symtab_symbol* symbols;
54 } symtab_t;
55
56 #ifdef __APPLE__
57
58 void build_search_table(symtab_t *symtab) {
59 int i;
60 for (i = 0; i < symtab->num_symbols; i++) {
61 DBT key, value;
62 key.data = symtab->symbols[i].name;
63 key.size = strlen(key.data) + 1;
64 value.data = &(symtab->symbols[i]);
65 value.size = sizeof(symtab_symbol);
66 (*symtab->hash_table->put)(symtab->hash_table, &key, &value, 0);
67
68 // check result
69 if (is_debug()) {
70 DBT rkey, rvalue;
71 char* tmp = (char *)malloc(strlen(symtab->symbols[i].name) + 1);
72 strcpy(tmp, symtab->symbols[i].name);
73 rkey.data = tmp;
74 rkey.size = strlen(tmp) + 1;
75 (*symtab->hash_table->get)(symtab->hash_table, &rkey, &rvalue, 0);
76 // we may get a copy back so compare contents
77 symtab_symbol *res = (symtab_symbol *)rvalue.data;
78 if (strcmp(res->name, symtab->symbols[i].name) ||
79 res->offset != symtab->symbols[i].offset ||
80 res->size != symtab->symbols[i].size) {
81 print_debug("error to get hash_table value!\n");
82 }
83 free(tmp);
84 }
85 }
86 }
87
88 // read symbol table from given fd.
89 struct symtab* build_symtab(int fd) {
90 symtab_t* symtab = NULL;
91 int i;
92 mach_header_64 header;
93 off_t image_start;
94
95 if (!get_arch_off(fd, CPU_TYPE_X86_64, &image_start)) {
96 print_debug("failed in get fat header\n");
97 return NULL;
98 }
99 lseek(fd, image_start, SEEK_SET);
100 if (read(fd, (void *)&header, sizeof(mach_header_64)) != sizeof(mach_header_64)) {
101 print_debug("reading header failed!\n");
102 return NULL;
103 }
104 // header
105 if (header.magic != MH_MAGIC_64) {
106 print_debug("not a valid .dylib file\n");
107 return NULL;
108 }
109
110 load_command lcmd;
111 symtab_command symtabcmd;
112 nlist_64 lentry;
113
114 bool lcsymtab_exist = false;
115
116 long filepos = ltell(fd);
117 for (i = 0; i < header.ncmds; i++) {
118 lseek(fd, filepos, SEEK_SET);
119 if (read(fd, (void *)&lcmd, sizeof(load_command)) != sizeof(load_command)) {
120 print_debug("read load_command failed for file\n");
121 return NULL;
122 }
123 filepos += lcmd.cmdsize; // next command position
124 if (lcmd.cmd == LC_SYMTAB) {
125 lseek(fd, -sizeof(load_command), SEEK_CUR);
126 lcsymtab_exist = true;
127 break;
128 }
129 }
130 if (!lcsymtab_exist) {
131 print_debug("No symtab command found!\n");
132 return NULL;
133 }
134 if (read(fd, (void *)&symtabcmd, sizeof(symtab_command)) != sizeof(symtab_command)) {
135 print_debug("read symtab_command failed for file");
136 return NULL;
137 }
138 symtab = (symtab_t *)malloc(sizeof(symtab_t));
139 if (symtab == NULL) {
140 print_debug("out of memory: allocating symtab\n");
141 return NULL;
142 }
143
144 // create hash table, we use berkeley db to
145 // manipulate the hash table.
146 symtab->hash_table = dbopen(NULL, O_CREAT | O_RDWR, 0600, DB_HASH, NULL);
147 if (symtab->hash_table == NULL)
148 goto quit;
149
150 symtab->num_symbols = symtabcmd.nsyms;
151 symtab->symbols = (symtab_symbol *)malloc(sizeof(symtab_symbol) * symtab->num_symbols);
152 symtab->strs = (char *)malloc(sizeof(char) * symtabcmd.strsize);
153 if (symtab->symbols == NULL || symtab->strs == NULL) {
154 print_debug("out of memory: allocating symtab.symbol or symtab.strs\n");
155 goto quit;
156 }
157 lseek(fd, image_start + symtabcmd.symoff, SEEK_SET);
158 for (i = 0; i < symtab->num_symbols; i++) {
159 if (read(fd, (void *)&lentry, sizeof(nlist_64)) != sizeof(nlist_64)) {
160 print_debug("read nlist_64 failed at %i\n", i);
161 goto quit;
162 }
163 symtab->symbols[i].offset = lentry.n_value;
164 symtab->symbols[i].size = lentry.n_un.n_strx; // index
165 }
166
167 // string table
168 lseek(fd, image_start + symtabcmd.stroff, SEEK_SET);
169 int size = read(fd, (void *)(symtab->strs), symtabcmd.strsize * sizeof(char));
170 if (size != symtabcmd.strsize * sizeof(char)) {
171 print_debug("reading string table failed\n");
172 goto quit;
173 }
174
175 for (i = 0; i < symtab->num_symbols; i++) {
176 symtab->symbols[i].name = symtab->strs + symtab->symbols[i].size;
177 if (i > 0) {
178 // fix size
179 symtab->symbols[i - 1].size = symtab->symbols[i].size - symtab->symbols[i - 1].size;
180 print_debug("%s size = %d\n", symtab->symbols[i - 1].name, symtab->symbols[i - 1].size);
181
182 }
183
184 if (i == symtab->num_symbols - 1) {
185 // last index
186 symtab->symbols[i].size =
187 symtabcmd.strsize - symtab->symbols[i].size;
188 print_debug("%s size = %d\n", symtab->symbols[i].name, symtab->symbols[i].size);
189 }
190 }
191
192 // build a hashtable for fast query
193 build_search_table(symtab);
194 return symtab;
195 quit:
196 if (symtab) destroy_symtab(symtab);
197 return NULL;
198 }
199
200 #else // __APPLE__
201
202 struct elf_section {
203 ELF_SHDR *c_shdr;
204 void *c_data;
205 };
206
207 // read symbol table from given fd.
208 struct symtab* build_symtab(int fd) {
209 ELF_EHDR ehdr;
210 struct symtab* symtab = NULL;
211
212 // Reading of elf header
213 struct elf_section *scn_cache = NULL;
214 int cnt = 0;
215 ELF_SHDR* shbuf = NULL;
216 ELF_SHDR* cursct = NULL;
217 ELF_PHDR* phbuf = NULL;
218 int symtab_found = 0;
219 int dynsym_found = 0;
220 uint32_t symsection = SHT_SYMTAB;
221
222 uintptr_t baseaddr = (uintptr_t)-1;
223
224 lseek(fd, (off_t)0L, SEEK_SET);
225 if (! read_elf_header(fd, &ehdr)) {
226 // not an elf
227 return NULL;
228 }
309
310 // copy symbols info our symtab and enter them info the hash table
311 for (j = 0; j < n; j++, syms++) {
312 DBT key, value;
313 char *sym_name = symtab->strs + syms->st_name;
314
315 // skip non-object and non-function symbols
316 int st_type = ELF_ST_TYPE(syms->st_info);
317 if ( st_type != STT_FUNC && st_type != STT_OBJECT)
318 continue;
319 // skip empty strings and undefined symbols
320 if (*sym_name == '\0' || syms->st_shndx == SHN_UNDEF) continue;
321
322 symtab->symbols[j].name = sym_name;
323 symtab->symbols[j].offset = syms->st_value - baseaddr;
324 symtab->symbols[j].size = syms->st_size;
325
326 key.data = sym_name;
327 key.size = strlen(sym_name) + 1;
328 value.data = &(symtab->symbols[j]);
329 value.size = sizeof(symtab_symbol);
330 (*symtab->hash_table->put)(symtab->hash_table, &key, &value, 0);
331 }
332 }
333 }
334 goto quit;
335
336 bad:
337 destroy_symtab(symtab);
338 symtab = NULL;
339
340 quit:
341 if (shbuf) free(shbuf);
342 if (phbuf) free(phbuf);
343 if (scn_cache) {
344 for (cnt = 0; cnt < ehdr.e_shnum; cnt++) {
345 if (scn_cache[cnt].c_data != NULL) {
346 free(scn_cache[cnt].c_data);
347 }
348 }
349 free(scn_cache);
350 }
351 return symtab;
352 }
353
354 #endif // __APPLE__
355
356 void destroy_symtab(symtab_t* symtab) {
357 if (!symtab) return;
358 free(symtab->strs);
359 free(symtab->symbols);
360 free(symtab);
361 }
362
363 uintptr_t search_symbol(struct symtab* symtab, uintptr_t base, const char *sym_name, int *sym_size) {
364 DBT key, value;
365 int ret;
366
367 // library does not have symbol table
368 if (!symtab || !symtab->hash_table) {
369 return 0;
370 }
371
372 key.data = (char*)(uintptr_t)sym_name;
373 key.size = strlen(sym_name) + 1;
374 ret = (*symtab->hash_table->get)(symtab->hash_table, &key, &value, 0);
375 if (ret == 0) {
376 symtab_symbol *sym = value.data;
377 uintptr_t rslt = (uintptr_t) ((char*)base + sym->offset);
378 if (sym_size) *sym_size = sym->size;
379 return rslt;
380 }
381
382 return 0;
383 }
384
385 const char* nearest_symbol(struct symtab* symtab, uintptr_t offset,
386 uintptr_t* poffset) {
387 int n = 0;
388 if (!symtab) return NULL;
389 for (; n < symtab->num_symbols; n++) {
390 symtab_symbol* sym = &(symtab->symbols[n]);
391 if (sym->name != NULL &&
392 offset >= sym->offset && offset < sym->offset + sym->size) {
393 if (poffset) *poffset = (offset - sym->offset);
394 return sym->name;
395 }
396 }
397 return NULL;
398 }
|