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1 | /* |
1 | /* |
2 | * Copyright (c) 2008 Jiri Svoboda |
2 | * Copyright (c) 2008 Jiri Svoboda |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | /** @addtogroup rtld rtld |
29 | /** @addtogroup rtld rtld |
30 | * @brief |
30 | * @brief |
31 | * @{ |
31 | * @{ |
32 | */ |
32 | */ |
33 | /** |
33 | /** |
34 | * @file |
34 | * @file |
35 | */ |
35 | */ |
36 | 36 | ||
37 | #include <stdio.h> |
37 | #include <stdio.h> |
38 | #include <stdlib.h> |
38 | #include <stdlib.h> |
39 | #include <string.h> |
39 | #include <string.h> |
40 | 40 | ||
41 | #include <rtld.h> |
41 | #include <rtld.h> |
42 | #include <symbol.h> |
42 | #include <symbol.h> |
43 | #include <elf.h> |
43 | #include <elf.h> |
44 | 44 | ||
45 | /* |
45 | /* |
46 | * Hash tables are 32-bit (elf_word) even for 64-bit ELF files. |
46 | * Hash tables are 32-bit (elf_word) even for 64-bit ELF files. |
47 | */ |
47 | */ |
48 | static elf_word elf_hash(const unsigned char *name) |
48 | static elf_word elf_hash(const unsigned char *name) |
49 | { |
49 | { |
50 | elf_word h = 0, g; |
50 | elf_word h = 0, g; |
51 | 51 | ||
52 | while (*name) { |
52 | while (*name) { |
53 | h = (h << 4) + *name++; |
53 | h = (h << 4) + *name++; |
54 | g = h & 0xf0000000; |
54 | g = h & 0xf0000000; |
55 | if (g != 0) h ^= g >> 24; |
55 | if (g != 0) h ^= g >> 24; |
56 | h &= ~g; |
56 | h &= ~g; |
57 | } |
57 | } |
58 | 58 | ||
59 | return h; |
59 | return h; |
60 | } |
60 | } |
61 | 61 | ||
62 | static elf_symbol_t *def_find_in_module(char *name, module_t *m) |
62 | static elf_symbol_t *def_find_in_module(char *name, module_t *m) |
63 | { |
63 | { |
64 | elf_symbol_t *sym_table; |
64 | elf_symbol_t *sym_table; |
65 | elf_symbol_t *s, *sym; |
65 | elf_symbol_t *s, *sym; |
66 | elf_word nbucket; |
66 | elf_word nbucket; |
67 | elf_word nchain; |
67 | elf_word nchain; |
68 | elf_word i; |
68 | elf_word i; |
69 | char *s_name; |
69 | char *s_name; |
70 | elf_word bucket; |
70 | elf_word bucket; |
71 | 71 | ||
72 | DPRINTF("def_find_in_module('%s', %s)\n", name, m->dyn.soname); |
72 | DPRINTF("def_find_in_module('%s', %s)\n", name, m->dyn.soname); |
73 | 73 | ||
74 | sym_table = m->dyn.sym_tab; |
74 | sym_table = m->dyn.sym_tab; |
75 | nbucket = m->dyn.hash[0]; |
75 | nbucket = m->dyn.hash[0]; |
76 | nchain = m->dyn.hash[1]; |
76 | nchain = m->dyn.hash[1]; |
77 | 77 | ||
78 | bucket = elf_hash((unsigned char *)name) % nbucket; |
78 | bucket = elf_hash((unsigned char *)name) % nbucket; |
79 | i = m->dyn.hash[2 + bucket]; |
79 | i = m->dyn.hash[2 + bucket]; |
80 | 80 | ||
81 | sym = NULL; |
81 | sym = NULL; |
82 | while (i != STN_UNDEF) { |
82 | while (i != STN_UNDEF) { |
83 | s = &sym_table[i]; |
83 | s = &sym_table[i]; |
84 | s_name = m->dyn.str_tab + s->st_name; |
84 | s_name = m->dyn.str_tab + s->st_name; |
85 | 85 | ||
86 | if (str_cmp(name, s_name) == 0) { |
86 | if (str_cmp(name, s_name) == 0) { |
87 | sym = s; |
87 | sym = s; |
88 | break; |
88 | break; |
89 | } |
89 | } |
90 | 90 | ||
91 | i = m->dyn.hash[2 + nbucket + i]; |
91 | i = m->dyn.hash[2 + nbucket + i]; |
92 | } |
92 | } |
93 | 93 | ||
94 | if (!sym) |
94 | if (!sym) |
95 | return NULL; /* Not found */ |
95 | return NULL; /* Not found */ |
96 | 96 | ||
97 | if (sym->st_shndx == SHN_UNDEF) { |
97 | if (sym->st_shndx == SHN_UNDEF) { |
98 | /* Not a definition */ |
98 | /* Not a definition */ |
99 | return NULL; |
99 | return NULL; |
100 | } |
100 | } |
101 | 101 | ||
102 | return sym; /* Found */ |
102 | return sym; /* Found */ |
103 | } |
103 | } |
104 | 104 | ||
105 | /** Find the definition of a symbol in a module and its deps. |
105 | /** Find the definition of a symbol in a module and its deps. |
106 | * |
106 | * |
107 | * Search the module dependency graph is breadth-first, beginning |
107 | * Search the module dependency graph is breadth-first, beginning |
108 | * from the module @a start. Thus, @start and all its dependencies |
108 | * from the module @a start. Thus, @start and all its dependencies |
109 | * get searched. |
109 | * get searched. |
110 | * |
110 | * |
111 | * @param name Name of the symbol to search for. |
111 | * @param name Name of the symbol to search for. |
112 | * @param start Module in which to start the search.. |
112 | * @param start Module in which to start the search.. |
113 | * @param mod (output) Will be filled with a pointer to the module |
113 | * @param mod (output) Will be filled with a pointer to the module |
114 | * that contains the symbol. |
114 | * that contains the symbol. |
115 | */ |
115 | */ |
116 | elf_symbol_t *symbol_bfs_find(char *name, module_t *start, module_t **mod) |
116 | elf_symbol_t *symbol_bfs_find(char *name, module_t *start, module_t **mod) |
117 | { |
117 | { |
118 | module_t *m, *dm; |
118 | module_t *m, *dm; |
119 | elf_symbol_t *sym, *s; |
119 | elf_symbol_t *sym, *s; |
120 | link_t queue_head; |
120 | link_t queue_head; |
121 | size_t i; |
121 | size_t i; |
122 | 122 | ||
123 | /* |
123 | /* |
124 | * Do a BFS using the queue_link and bfs_tag fields. |
124 | * Do a BFS using the queue_link and bfs_tag fields. |
125 | * Vertices (modules) are tagged the moment they are inserted |
125 | * Vertices (modules) are tagged the moment they are inserted |
126 | * into the queue. This prevents from visiting the same vertex |
126 | * into the queue. This prevents from visiting the same vertex |
127 | * more times in case of circular dependencies. |
127 | * more times in case of circular dependencies. |
128 | */ |
128 | */ |
129 | 129 | ||
130 | /* Mark all vertices (modules) as unvisited */ |
130 | /* Mark all vertices (modules) as unvisited */ |
131 | modules_untag(); |
131 | modules_untag(); |
132 | 132 | ||
133 | /* Insert root (the program) into the queue and tag it */ |
133 | /* Insert root (the program) into the queue and tag it */ |
134 | list_initialize(&queue_head); |
134 | list_initialize(&queue_head); |
135 | start->bfs_tag = true; |
135 | start->bfs_tag = true; |
136 | list_append(&start->queue_link, &queue_head); |
136 | list_append(&start->queue_link, &queue_head); |
137 | 137 | ||
138 | /* If the symbol is found, it will be stored in 'sym' */ |
138 | /* If the symbol is found, it will be stored in 'sym' */ |
139 | sym = NULL; |
139 | sym = NULL; |
140 | 140 | ||
141 | /* While queue is not empty */ |
141 | /* While queue is not empty */ |
142 | while (!list_empty(&queue_head)) { |
142 | while (!list_empty(&queue_head)) { |
143 | /* Pop first element from the queue */ |
143 | /* Pop first element from the queue */ |
144 | m = list_get_instance(queue_head.next, module_t, queue_link); |
144 | m = list_get_instance(queue_head.next, module_t, queue_link); |
145 | list_remove(&m->queue_link); |
145 | list_remove(&m->queue_link); |
146 | 146 | ||
147 | s = def_find_in_module(name, m); |
147 | s = def_find_in_module(name, m); |
148 | if (s != NULL) { |
148 | if (s != NULL) { |
149 | /* Symbol found */ |
149 | /* Symbol found */ |
150 | sym = s; |
150 | sym = s; |
151 | *mod = m; |
151 | *mod = m; |
152 | break; |
152 | break; |
153 | } |
153 | } |
154 | 154 | ||
155 | /* |
155 | /* |
156 | * Insert m's untagged dependencies into the queue |
156 | * Insert m's untagged dependencies into the queue |
157 | * and tag them. |
157 | * and tag them. |
158 | */ |
158 | */ |
159 | for (i = 0; i < m->n_deps; ++i) { |
159 | for (i = 0; i < m->n_deps; ++i) { |
160 | dm = m->deps[i]; |
160 | dm = m->deps[i]; |
161 | 161 | ||
162 | if (dm->bfs_tag == false) { |
162 | if (dm->bfs_tag == false) { |
163 | dm->bfs_tag = true; |
163 | dm->bfs_tag = true; |
164 | list_append(&dm->queue_link, &queue_head); |
164 | list_append(&dm->queue_link, &queue_head); |
165 | } |
165 | } |
166 | } |
166 | } |
167 | } |
167 | } |
168 | 168 | ||
169 | /* Empty the queue so that we leave it in a clean state */ |
169 | /* Empty the queue so that we leave it in a clean state */ |
170 | while (!list_empty(&queue_head)) |
170 | while (!list_empty(&queue_head)) |
171 | list_remove(queue_head.next); |
171 | list_remove(queue_head.next); |
172 | 172 | ||
173 | if (!sym) { |
173 | if (!sym) { |
174 | printf("Error, symbol '%s' not found anywhere\n", name); |
- | |
175 | exit(1); |
- | |
176 | return NULL; /* Not found */ |
174 | return NULL; /* Not found */ |
177 | } |
175 | } |
178 | 176 | ||
179 | return sym; /* Symbol found */ |
177 | return sym; /* Symbol found */ |
180 | } |
178 | } |
181 | 179 | ||
182 | 180 | ||
183 | /** Find the definition of a symbol.. |
181 | /** Find the definition of a symbol.. |
184 | * |
182 | * |
185 | * By definition in System V ABI, if module origin has the flag DT_SYMBOLIC, |
183 | * By definition in System V ABI, if module origin has the flag DT_SYMBOLIC, |
186 | * origin is searched first. Otherwise, or if the symbol hasn't been found, |
184 | * origin is searched first. Otherwise, or if the symbol hasn't been found, |
187 | * the module dependency graph is searched breadth-first, beginning |
185 | * the module dependency graph is searched breadth-first, beginning |
188 | * from the executable program. |
186 | * from the executable program. |
189 | * |
187 | * |
190 | * @param name Name of the symbol to search for. |
188 | * @param name Name of the symbol to search for. |
191 | * @param origin Module in which the dependency originates. |
189 | * @param origin Module in which the dependency originates. |
192 | * @param mod (output) Will be filled with a pointer to the module |
190 | * @param mod (output) Will be filled with a pointer to the module |
193 | * that contains the symbol. |
191 | * that contains the symbol. |
194 | */ |
192 | */ |
195 | elf_symbol_t *symbol_def_find(char *name, module_t *origin, module_t **mod) |
193 | elf_symbol_t *symbol_def_find(char *name, module_t *origin, module_t **mod) |
196 | { |
194 | { |
197 | module_t *m, *dm; |
195 | module_t *m, *dm; |
198 | elf_symbol_t *sym, *s; |
196 | elf_symbol_t *sym, *s; |
199 | link_t queue_head; |
197 | link_t queue_head; |
200 | size_t i; |
198 | size_t i; |
201 | 199 | ||
202 | if (origin->dyn.symbolic) { |
200 | if (origin->dyn.symbolic) { |
203 | /* |
201 | /* |
204 | * Origin module has a DT_SYMBOLIC flag. |
202 | * Origin module has a DT_SYMBOLIC flag. |
205 | * Try this module first |
203 | * Try this module first |
206 | */ |
204 | */ |
207 | s = def_find_in_module(name, origin); |
205 | s = def_find_in_module(name, origin); |
208 | if (s != NULL) { |
206 | if (s != NULL) { |
209 | /* Found */ |
207 | /* Found */ |
210 | *mod = origin; |
208 | *mod = origin; |
211 | return s; |
209 | return s; |
212 | } |
210 | } |
213 | } |
211 | } |
214 | 212 | ||
215 | /* Not DT_SYMBOLIC or no match. Now try other locations. */ |
213 | /* Not DT_SYMBOLIC or no match. Now try other locations. */ |
216 | 214 | ||
217 | if (runtime_env->program) { |
215 | if (runtime_env->program) { |
218 | /* Program is dynamic -- start with program as root. */ |
216 | /* Program is dynamic -- start with program as root. */ |
219 | return symbol_bfs_find(name, runtime_env->program, mod); |
217 | return symbol_bfs_find(name, runtime_env->program, mod); |
220 | } else { |
218 | } else { |
221 | /* Program is static -- start with @a origin as root. */ |
219 | /* Program is static -- start with @a origin as root. */ |
222 | return symbol_bfs_find(name, origin, mod); |
220 | return symbol_bfs_find(name, origin, mod); |
223 | } |
221 | } |
224 | } |
222 | } |
225 | 223 | ||
226 | uintptr_t symbol_get_addr(elf_symbol_t *sym, module_t *m) |
224 | uintptr_t symbol_get_addr(elf_symbol_t *sym, module_t *m) |
227 | { |
225 | { |
228 | if (sym->st_shndx == SHN_ABS) { |
226 | if (sym->st_shndx == SHN_ABS) { |
229 | /* Do not add bias to absolute symbols */ |
227 | /* Do not add bias to absolute symbols */ |
230 | return sym->st_value; |
228 | return sym->st_value; |
231 | } else { |
229 | } else { |
232 | return sym->st_value + m->bias; |
230 | return sym->st_value + m->bias; |
233 | } |
231 | } |
234 | } |
232 | } |
235 | 233 | ||
236 | /** @} |
234 | /** @} |
237 | */ |
235 | */ |
238 | 236 |