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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 | // module_name = m->dyn.soname; |
72 | // module_name = m->dyn.soname; |
73 | // printf("def_find_in_module('%s', %s)\n", name, module_name); |
73 | // printf("def_find_in_module('%s', %s)\n", name, module_name); |
74 | 74 | ||
75 | sym_table = m->dyn.sym_tab; |
75 | sym_table = m->dyn.sym_tab; |
76 | nbucket = m->dyn.hash[0]; |
76 | nbucket = m->dyn.hash[0]; |
77 | nchain = m->dyn.hash[1]; |
77 | nchain = m->dyn.hash[1]; |
78 | 78 | ||
79 | bucket = elf_hash((unsigned char *)name) % nbucket; |
79 | bucket = elf_hash((unsigned char *)name) % nbucket; |
80 | i = m->dyn.hash[2 + bucket]; |
80 | i = m->dyn.hash[2 + bucket]; |
81 | 81 | ||
82 | sym = NULL; |
82 | sym = NULL; |
83 | while (i != STN_UNDEF) { |
83 | while (i != STN_UNDEF) { |
84 | s = &sym_table[i]; |
84 | s = &sym_table[i]; |
85 | s_name = m->dyn.str_tab + s->st_name; |
85 | s_name = m->dyn.str_tab + s->st_name; |
86 | 86 | ||
87 | if (strcmp(name, s_name) == 0) { |
87 | if (strcmp(name, s_name) == 0) { |
88 | sym = s; |
88 | sym = s; |
89 | break; |
89 | break; |
90 | } |
90 | } |
91 | 91 | ||
92 | i = m->dyn.hash[2 + nbucket + i]; |
92 | i = m->dyn.hash[2 + nbucket + i]; |
93 | } |
93 | } |
94 | 94 | ||
95 | if (!sym) |
95 | if (!sym) |
96 | return NULL; /* Not found */ |
96 | return NULL; /* Not found */ |
97 | 97 | ||
98 | if (sym->st_shndx == SHN_UNDEF) { |
98 | if (sym->st_shndx == SHN_UNDEF) { |
99 | /* Not a definition */ |
99 | /* Not a definition */ |
100 | return NULL; |
100 | return NULL; |
101 | } |
101 | } |
102 | 102 | ||
103 | return sym; /* Found */ |
103 | return sym; /* Found */ |
104 | } |
104 | } |
105 | 105 | ||
106 | /** Find the definition of a symbol. |
106 | /** Find the definition of a symbol. |
107 | * |
107 | * |
108 | * By definition in System V ABI, if module origin has the flag DT_SYMBOLIC, |
108 | * By definition in System V ABI, if module origin has the flag DT_SYMBOLIC, |
109 | * origin is searched first. Otherwise, or if the symbol hasn't been found, |
109 | * origin is searched first. Otherwise, or if the symbol hasn't been found, |
110 | * the module dependency graph is searched breadth-first, beginning |
110 | * the module dependency graph is searched breadth-first, beginning |
111 | * from the executable program. |
111 | * from the executable program. |
112 | * |
112 | * |
113 | * @param name Name of the symbol to search for. |
113 | * @param name Name of the symbol to search for. |
114 | * @param origin Module in which the dependency originates. |
114 | * @param origin Module in which the dependency originates. |
115 | * @param mod (output) Will be filled with a pointer to the module |
115 | * @param mod (output) Will be filled with a pointer to the module |
116 | * that contains the symbol. |
116 | * that contains the symbol. |
117 | */ |
117 | */ |
118 | elf_symbol_t *symbol_def_find(char *name, module_t *origin, module_t **mod) |
118 | elf_symbol_t *symbol_def_find(char *name, module_t *origin, module_t **mod) |
119 | { |
119 | { |
120 | module_t *m; |
120 | module_t *m, *dm; |
121 | elf_symbol_t *sym; |
121 | elf_symbol_t *sym, *s; |
- | 122 | link_t queue_head; |
|
- | 123 | size_t i; |
|
122 | 124 | ||
- | 125 | if (origin->dyn.symbolic) { |
|
- | 126 | /* |
|
123 | /* FIXME: support DT_SYMBOLIC */ |
127 | * Origin module has a DT_SYMBOLIC flag. |
- | 128 | * Try this module first |
|
- | 129 | */ |
|
- | 130 | s = def_find_in_module(name, origin); |
|
- | 131 | if (s != NULL) { |
|
- | 132 | /* Found */ |
|
124 | //m = origin; |
133 | *mod = origin; |
- | 134 | return s; |
|
- | 135 | } |
|
- | 136 | } |
|
125 | 137 | ||
126 | /* Start in the executable program */ |
138 | /* Otherwise start in the executable program */ |
127 | m = runtime_env.program; |
- | |
128 | 139 | ||
- | 140 | /* |
|
- | 141 | * Do a BFS using the queue_link and bfs_tag fields. |
|
- | 142 | * Vertices (modules) are tagged the moment they are inserted |
|
- | 143 | * into the queue. This prevents from visiting the same vertex |
|
- | 144 | * more times in case of circular dependencies. |
|
- | 145 | */ |
|
- | 146 | ||
- | 147 | /* Mark all vertices (modules) as unvisited */ |
|
129 | while (true) { |
148 | modules_untag(); |
- | 149 | ||
- | 150 | /* Insert root (the program) into the queue and tag it */ |
|
- | 151 | list_initialize(&queue_head); |
|
- | 152 | runtime_env.program->bfs_tag = true; |
|
- | 153 | list_append(&runtime_env.program->queue_link, &queue_head); |
|
- | 154 | ||
- | 155 | /* If the symbol is found, it will be stored in 'sym' */ |
|
- | 156 | sym = NULL; |
|
- | 157 | ||
- | 158 | /* While queue is not empty */ |
|
- | 159 | while (!list_empty(&queue_head)) { |
|
- | 160 | /* Pop first element from the queue */ |
|
- | 161 | m = list_get_instance(queue_head.next, module_t, queue_link); |
|
- | 162 | list_remove(&m->queue_link); |
|
- | 163 | ||
130 | sym = def_find_in_module(name, m); |
164 | s = def_find_in_module(name, m); |
131 | if (sym != NULL) { |
165 | if (s != NULL) { |
- | 166 | /* Symbol found */ |
|
- | 167 | sym = s; |
|
132 | *mod = m; |
168 | *mod = m; |
133 | return sym; |
169 | break; |
134 | } |
170 | } |
135 | 171 | ||
- | 172 | /* |
|
- | 173 | * Insert m's untagged dependencies into the queue |
|
- | 174 | * and tag them. |
|
- | 175 | */ |
|
- | 176 | for (i = 0; i < m->n_deps; ++i) { |
|
136 | if (m->n_deps < 1) break; |
177 | dm = m->deps[i]; |
137 | 178 | ||
138 | /* FIXME: support branching */ |
179 | if (dm->bfs_tag == false) { |
139 | if (m->n_deps > 1) { |
180 | dm->bfs_tag = true; |
140 | printf("error: BFS unimplemented\n"); |
181 | list_append(&dm->queue_link, &queue_head); |
141 | exit(1); |
182 | } |
142 | } |
183 | } |
143 | - | ||
144 | m = m->deps[0]; |
- | |
145 | } |
184 | } |
146 | 185 | ||
- | 186 | /* Empty the queue so that we leave it in a clean state */ |
|
- | 187 | while (!list_empty(&queue_head)) |
|
- | 188 | list_remove(queue_head.next); |
|
- | 189 | ||
- | 190 | if (!sym) { |
|
147 | printf("Error, symbol '%s' not found anywhere\n", name); |
191 | printf("Error, symbol '%s' not found anywhere\n", name); |
148 | exit(1); |
192 | exit(1); |
149 | return NULL; /* Not found */ |
193 | return NULL; /* Not found */ |
150 | } |
194 | } |
- | 195 | ||
- | 196 | return sym; /* Symbol found */ |
|
- | 197 | } |
|
151 | 198 | ||
152 | uintptr_t symbol_get_addr(elf_symbol_t *sym, module_t *m) |
199 | uintptr_t symbol_get_addr(elf_symbol_t *sym, module_t *m) |
153 | { |
200 | { |
154 | if (sym->st_shndx == SHN_ABS) { |
201 | if (sym->st_shndx == SHN_ABS) { |
155 | /* Do not add bias to absolute symbols */ |
202 | /* Do not add bias to absolute symbols */ |
156 | return sym->st_value; |
203 | return sym->st_value; |
157 | } else { |
204 | } else { |
158 | return sym->st_value + m->bias; |
205 | return sym->st_value + m->bias; |
159 | } |
206 | } |
160 | } |
207 | } |
161 | 208 | ||
162 | /** @} |
209 | /** @} |
163 | */ |
210 | */ |
164 | 211 |