Mercurial > hg > truffle
comparison agent/src/os/bsd/symtab.c @ 3960:f08d439fab8c
7089790: integrate bsd-port changes
Reviewed-by: kvn, twisti, jrose
Contributed-by: Kurt Miller <kurt@intricatesoftware.com>, Greg Lewis <glewis@eyesbeyond.com>, Jung-uk Kim <jkim@freebsd.org>, Christos Zoulas <christos@zoulas.com>, Landon Fuller <landonf@plausible.coop>, The FreeBSD Foundation <board@freebsdfoundation.org>, Michael Franz <mvfranz@gmail.com>, Roger Hoover <rhoover@apple.com>, Alexander Strange <astrange@apple.com>
author | never |
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date | Sun, 25 Sep 2011 16:03:29 -0700 |
parents | |
children | 436b4a3231bf |
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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 } | |
79 | |
80 // read ELF header | |
81 if ((shbuf = read_section_header_table(fd, &ehdr)) == NULL) { | |
82 goto quit; | |
83 } | |
84 | |
85 baseaddr = find_base_address(fd, &ehdr); | |
86 | |
87 scn_cache = calloc(ehdr.e_shnum, sizeof(*scn_cache)); | |
88 if (scn_cache == NULL) { | |
89 goto quit; | |
90 } | |
91 | |
92 for (cursct = shbuf, cnt = 0; cnt < ehdr.e_shnum; cnt++) { | |
93 scn_cache[cnt].c_shdr = cursct; | |
94 if (cursct->sh_type == SHT_SYMTAB || | |
95 cursct->sh_type == SHT_STRTAB || | |
96 cursct->sh_type == SHT_DYNSYM) { | |
97 if ( (scn_cache[cnt].c_data = read_section_data(fd, &ehdr, cursct)) == NULL) { | |
98 goto quit; | |
99 } | |
100 } | |
101 | |
102 if (cursct->sh_type == SHT_SYMTAB) | |
103 symtab_found++; | |
104 | |
105 if (cursct->sh_type == SHT_DYNSYM) | |
106 dynsym_found++; | |
107 | |
108 cursct++; | |
109 } | |
110 | |
111 if (!symtab_found && dynsym_found) | |
112 symsection = SHT_DYNSYM; | |
113 | |
114 for (cnt = 1; cnt < ehdr.e_shnum; cnt++) { | |
115 ELF_SHDR *shdr = scn_cache[cnt].c_shdr; | |
116 | |
117 if (shdr->sh_type == symsection) { | |
118 ELF_SYM *syms; | |
119 int j, n, rslt; | |
120 size_t size; | |
121 | |
122 // FIXME: there could be multiple data buffers associated with the | |
123 // same ELF section. Here we can handle only one buffer. See man page | |
124 // for elf_getdata on Solaris. | |
125 | |
126 // guarantee(symtab == NULL, "multiple symtab"); | |
127 symtab = calloc(1, sizeof(*symtab)); | |
128 if (symtab == NULL) { | |
129 goto quit; | |
130 } | |
131 // the symbol table | |
132 syms = (ELF_SYM *)scn_cache[cnt].c_data; | |
133 | |
134 // number of symbols | |
135 n = shdr->sh_size / shdr->sh_entsize; | |
136 | |
137 // create hash table, we use berkeley db to | |
138 // manipulate the hash table. | |
139 symtab->hash_table = dbopen(NULL, O_CREAT | O_RDWR, 0600, DB_HASH, NULL); | |
140 // guarantee(symtab->hash_table, "unexpected failure: dbopen"); | |
141 | |
142 // shdr->sh_link points to the section that contains the actual strings | |
143 // for symbol names. the st_name field in ELF_SYM is just the | |
144 // string table index. we make a copy of the string table so the | |
145 // strings will not be destroyed by elf_end. | |
146 size = scn_cache[shdr->sh_link].c_shdr->sh_size; | |
147 symtab->strs = malloc(size); | |
148 memcpy(symtab->strs, scn_cache[shdr->sh_link].c_data, size); | |
149 | |
150 // allocate memory for storing symbol offset and size; | |
151 symtab->num_symbols = n; | |
152 symtab->symbols = calloc(n , sizeof(*symtab->symbols)); | |
153 | |
154 // copy symbols info our symtab and enter them info the hash table | |
155 for (j = 0; j < n; j++, syms++) { | |
156 DBT key, value; | |
157 char *sym_name = symtab->strs + syms->st_name; | |
158 | |
159 // skip non-object and non-function symbols | |
160 int st_type = ELF_ST_TYPE(syms->st_info); | |
161 if ( st_type != STT_FUNC && st_type != STT_OBJECT) | |
162 continue; | |
163 // skip empty strings and undefined symbols | |
164 if (*sym_name == '\0' || syms->st_shndx == SHN_UNDEF) continue; | |
165 | |
166 symtab->symbols[j].name = sym_name; | |
167 symtab->symbols[j].offset = syms->st_value - baseaddr; | |
168 symtab->symbols[j].size = syms->st_size; | |
169 | |
170 key.data = sym_name; | |
171 key.size = strlen(sym_name) + 1; | |
172 value.data = &(symtab->symbols[j]); | |
173 value.size = sizeof(void *); | |
174 (*symtab->hash_table->put)(symtab->hash_table, &key, &value, 0); | |
175 } | |
176 } | |
177 } | |
178 | |
179 quit: | |
180 if (shbuf) free(shbuf); | |
181 if (phbuf) free(phbuf); | |
182 if (scn_cache) { | |
183 for (cnt = 0; cnt < ehdr.e_shnum; cnt++) { | |
184 if (scn_cache[cnt].c_data != NULL) { | |
185 free(scn_cache[cnt].c_data); | |
186 } | |
187 } | |
188 free(scn_cache); | |
189 } | |
190 return symtab; | |
191 } | |
192 | |
193 void destroy_symtab(struct symtab* symtab) { | |
194 if (!symtab) return; | |
195 if (symtab->strs) free(symtab->strs); | |
196 if (symtab->symbols) free(symtab->symbols); | |
197 if (symtab->hash_table) { | |
198 symtab->hash_table->close(symtab->hash_table); | |
199 } | |
200 free(symtab); | |
201 } | |
202 | |
203 uintptr_t search_symbol(struct symtab* symtab, uintptr_t base, | |
204 const char *sym_name, int *sym_size) { | |
205 DBT key, value; | |
206 int ret; | |
207 | |
208 // library does not have symbol table | |
209 if (!symtab || !symtab->hash_table) | |
210 return 0; | |
211 | |
212 key.data = (char*)(uintptr_t)sym_name; | |
213 key.size = strlen(sym_name) + 1; | |
214 ret = (*symtab->hash_table->get)(symtab->hash_table, &key, &value, 0); | |
215 if (ret == 0) { | |
216 struct elf_symbol *sym = value.data; | |
217 uintptr_t rslt = (uintptr_t) ((char*)base + sym->offset); | |
218 if (sym_size) *sym_size = sym->size; | |
219 return rslt; | |
220 } | |
221 | |
222 quit: | |
223 return 0; | |
224 } | |
225 | |
226 const char* nearest_symbol(struct symtab* symtab, uintptr_t offset, | |
227 uintptr_t* poffset) { | |
228 int n = 0; | |
229 if (!symtab) return NULL; | |
230 for (; n < symtab->num_symbols; n++) { | |
231 struct elf_symbol* sym = &(symtab->symbols[n]); | |
232 if (sym->name != NULL && | |
233 offset >= sym->offset && offset < sym->offset + sym->size) { | |
234 if (poffset) *poffset = (offset - sym->offset); | |
235 return sym->name; | |
236 } | |
237 } | |
238 return NULL; | |
239 } |