Mercurial > hg > graal-jvmci-8
comparison agent/src/os/linux/symtab.c @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | 7de45b5044c3 |
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-1:000000000000 | 0:a61af66fc99e |
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1 /* | |
2 * Copyright 2003-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 #include <unistd.h> | |
26 #include <sys/procfs.h> | |
27 #include <search.h> | |
28 #include <stdlib.h> | |
29 #include <string.h> | |
30 #include "symtab.h" | |
31 #include "salibelf.h" | |
32 | |
33 | |
34 // ---------------------------------------------------- | |
35 // functions for symbol lookups | |
36 // ---------------------------------------------------- | |
37 | |
38 struct elf_section { | |
39 ELF_SHDR *c_shdr; | |
40 void *c_data; | |
41 }; | |
42 | |
43 struct elf_symbol { | |
44 char *name; | |
45 uintptr_t offset; | |
46 uintptr_t size; | |
47 }; | |
48 | |
49 typedef struct symtab { | |
50 char *strs; | |
51 size_t num_symbols; | |
52 struct elf_symbol *symbols; | |
53 struct hsearch_data *hash_table; | |
54 } symtab_t; | |
55 | |
56 // read symbol table from given fd. | |
57 struct symtab* build_symtab(int fd) { | |
58 ELF_EHDR ehdr; | |
59 char *names = NULL; | |
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 ELF_PHDR* phdr = NULL; | |
69 | |
70 uintptr_t baseaddr = (uintptr_t)-1; | |
71 | |
72 lseek(fd, (off_t)0L, SEEK_SET); | |
73 if (! read_elf_header(fd, &ehdr)) { | |
74 // not an elf | |
75 return NULL; | |
76 } | |
77 | |
78 // read ELF header | |
79 if ((shbuf = read_section_header_table(fd, &ehdr)) == NULL) { | |
80 goto quit; | |
81 } | |
82 | |
83 baseaddr = find_base_address(fd, &ehdr); | |
84 | |
85 scn_cache = (struct elf_section *) | |
86 calloc(ehdr.e_shnum * sizeof(struct elf_section), 1); | |
87 if (scn_cache == NULL) { | |
88 goto quit; | |
89 } | |
90 | |
91 for (cursct = shbuf, cnt = 0; cnt < ehdr.e_shnum; cnt++) { | |
92 scn_cache[cnt].c_shdr = cursct; | |
93 if (cursct->sh_type == SHT_SYMTAB || cursct->sh_type == SHT_STRTAB) { | |
94 if ( (scn_cache[cnt].c_data = read_section_data(fd, &ehdr, cursct)) == NULL) { | |
95 goto quit; | |
96 } | |
97 } | |
98 cursct++; | |
99 } | |
100 | |
101 for (cnt = 1; cnt < ehdr.e_shnum; cnt++) { | |
102 ELF_SHDR *shdr = scn_cache[cnt].c_shdr; | |
103 | |
104 if (shdr->sh_type == SHT_SYMTAB) { | |
105 ELF_SYM *syms; | |
106 int j, n, rslt; | |
107 size_t size; | |
108 | |
109 // FIXME: there could be multiple data buffers associated with the | |
110 // same ELF section. Here we can handle only one buffer. See man page | |
111 // for elf_getdata on Solaris. | |
112 | |
113 // guarantee(symtab == NULL, "multiple symtab"); | |
114 symtab = (struct symtab*)calloc(1, sizeof(struct symtab)); | |
115 if (symtab == NULL) { | |
116 goto quit; | |
117 } | |
118 // the symbol table | |
119 syms = (ELF_SYM *)scn_cache[cnt].c_data; | |
120 | |
121 // number of symbols | |
122 n = shdr->sh_size / shdr->sh_entsize; | |
123 | |
124 // create hash table, we use hcreate_r, hsearch_r and hdestroy_r to | |
125 // manipulate the hash table. | |
126 symtab->hash_table = (struct hsearch_data*) calloc(1, sizeof(struct hsearch_data)); | |
127 rslt = hcreate_r(n, symtab->hash_table); | |
128 // guarantee(rslt, "unexpected failure: hcreate_r"); | |
129 | |
130 // shdr->sh_link points to the section that contains the actual strings | |
131 // for symbol names. the st_name field in ELF_SYM is just the | |
132 // string table index. we make a copy of the string table so the | |
133 // strings will not be destroyed by elf_end. | |
134 size = scn_cache[shdr->sh_link].c_shdr->sh_size; | |
135 symtab->strs = (char *)malloc(size); | |
136 memcpy(symtab->strs, scn_cache[shdr->sh_link].c_data, size); | |
137 | |
138 // allocate memory for storing symbol offset and size; | |
139 symtab->num_symbols = n; | |
140 symtab->symbols = (struct elf_symbol *)calloc(n , sizeof(struct elf_symbol)); | |
141 | |
142 // copy symbols info our symtab and enter them info the hash table | |
143 for (j = 0; j < n; j++, syms++) { | |
144 ENTRY item, *ret; | |
145 char *sym_name = symtab->strs + syms->st_name; | |
146 | |
147 // skip non-object and non-function symbols | |
148 int st_type = ELF_ST_TYPE(syms->st_info); | |
149 if ( st_type != STT_FUNC && st_type != STT_OBJECT) | |
150 continue; | |
151 // skip empty strings and undefined symbols | |
152 if (*sym_name == '\0' || syms->st_shndx == SHN_UNDEF) continue; | |
153 | |
154 symtab->symbols[j].name = sym_name; | |
155 symtab->symbols[j].offset = syms->st_value - baseaddr; | |
156 symtab->symbols[j].size = syms->st_size; | |
157 | |
158 item.key = sym_name; | |
159 item.data = (void *)&(symtab->symbols[j]); | |
160 | |
161 hsearch_r(item, ENTER, &ret, symtab->hash_table); | |
162 } | |
163 } | |
164 } | |
165 | |
166 quit: | |
167 if (shbuf) free(shbuf); | |
168 if (phbuf) free(phbuf); | |
169 if (scn_cache) { | |
170 for (cnt = 0; cnt < ehdr.e_shnum; cnt++) { | |
171 if (scn_cache[cnt].c_data != NULL) { | |
172 free(scn_cache[cnt].c_data); | |
173 } | |
174 } | |
175 free(scn_cache); | |
176 } | |
177 return symtab; | |
178 } | |
179 | |
180 void destroy_symtab(struct symtab* symtab) { | |
181 if (!symtab) return; | |
182 if (symtab->strs) free(symtab->strs); | |
183 if (symtab->symbols) free(symtab->symbols); | |
184 if (symtab->hash_table) { | |
185 hdestroy_r(symtab->hash_table); | |
186 free(symtab->hash_table); | |
187 } | |
188 free(symtab); | |
189 } | |
190 | |
191 uintptr_t search_symbol(struct symtab* symtab, uintptr_t base, | |
192 const char *sym_name, int *sym_size) { | |
193 ENTRY item; | |
194 ENTRY* ret = NULL; | |
195 | |
196 // library does not have symbol table | |
197 if (!symtab || !symtab->hash_table) | |
198 return (uintptr_t)NULL; | |
199 | |
200 item.key = (char*) strdup(sym_name); | |
201 hsearch_r(item, FIND, &ret, symtab->hash_table); | |
202 if (ret) { | |
203 struct elf_symbol * sym = (struct elf_symbol *)(ret->data); | |
204 uintptr_t rslt = (uintptr_t) ((char*)base + sym->offset); | |
205 if (sym_size) *sym_size = sym->size; | |
206 free(item.key); | |
207 return rslt; | |
208 } | |
209 | |
210 quit: | |
211 free(item.key); | |
212 return (uintptr_t) NULL; | |
213 } | |
214 | |
215 const char* nearest_symbol(struct symtab* symtab, uintptr_t offset, | |
216 uintptr_t* poffset) { | |
217 int n = 0; | |
218 if (!symtab) return NULL; | |
219 for (; n < symtab->num_symbols; n++) { | |
220 struct elf_symbol* sym = &(symtab->symbols[n]); | |
221 if (sym->name != NULL && | |
222 offset >= sym->offset && offset < sym->offset + sym->size) { | |
223 if (poffset) *poffset = (offset - sym->offset); | |
224 return sym->name; | |
225 } | |
226 } | |
227 return NULL; | |
228 } |