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| Rev | Author | Line No. | Line |
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| 2978 | svoboda | 1 | /* |
| 2 | * Copyright (c) 2008 Jiri Svoboda |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 29 | /** @addtogroup rtld rtld |
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| 30 | * @brief |
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| 31 | * @{ |
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| 32 | */ |
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| 33 | /** |
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| 34 | * @file |
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| 35 | */ |
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| 36 | |||
| 37 | #include <stdio.h> |
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| 38 | #include <stdlib.h> |
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| 39 | #include <string.h> |
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| 40 | |||
| 41 | #include <rtld.h> |
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| 42 | #include <symbol.h> |
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| 43 | #include <elf.h> |
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| 44 | |||
| 2998 | svoboda | 45 | /* |
| 46 | * Hash tables are 32-bit (elf_word) even for 64-bit ELF files. |
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| 47 | */ |
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| 48 | static elf_word elf_hash(const unsigned char *name) |
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| 49 | { |
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| 50 | elf_word h = 0, g; |
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| 51 | |||
| 52 | while (*name) { |
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| 53 | h = (h << 4) + *name++; |
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| 54 | g = h & 0xf0000000; |
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| 55 | if (g != 0) h ^= g >> 24; |
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| 56 | h &= ~g; |
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| 57 | } |
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| 58 | |||
| 59 | return h; |
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| 60 | } |
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| 61 | |||
| 2980 | svoboda | 62 | static elf_symbol_t *def_find_in_module(char *name, module_t *m) |
| 2978 | svoboda | 63 | { |
| 64 | elf_symbol_t *sym_table; |
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| 2998 | svoboda | 65 | elf_symbol_t *s, *sym; |
| 66 | elf_word nbucket; |
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| 2978 | svoboda | 67 | elf_word nchain; |
| 2998 | svoboda | 68 | elf_word i; |
| 2978 | svoboda | 69 | char *s_name; |
| 2998 | svoboda | 70 | elf_word bucket; |
| 2978 | svoboda | 71 | |
| 2998 | svoboda | 72 | // module_name = m->dyn.soname; |
| 2981 | svoboda | 73 | // printf("def_find_in_module('%s', %s)\n", name, module_name); |
| 2978 | svoboda | 74 | |
| 75 | sym_table = m->dyn.sym_tab; |
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| 2998 | svoboda | 76 | nbucket = m->dyn.hash[0]; |
| 2978 | svoboda | 77 | nchain = m->dyn.hash[1]; |
| 78 | |||
| 2998 | svoboda | 79 | bucket = elf_hash((unsigned char *)name) % nbucket; |
| 80 | i = m->dyn.hash[2 + bucket]; |
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| 81 | |||
| 82 | sym = NULL; |
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| 83 | while (i != STN_UNDEF) { |
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| 84 | s = &sym_table[i]; |
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| 85 | s_name = m->dyn.str_tab + s->st_name; |
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| 86 | |||
| 2978 | svoboda | 87 | if (strcmp(name, s_name) == 0) { |
| 2998 | svoboda | 88 | sym = s; |
| 89 | break; |
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| 2978 | svoboda | 90 | } |
| 2998 | svoboda | 91 | |
| 92 | i = m->dyn.hash[2 + nbucket + i]; |
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| 2978 | svoboda | 93 | } |
| 94 | |||
| 2998 | svoboda | 95 | if (!sym) |
| 96 | return NULL; /* Not found */ |
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| 97 | |||
| 98 | if (sym->st_shndx == SHN_UNDEF) { |
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| 99 | /* Not a definition */ |
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| 100 | return NULL; |
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| 101 | } |
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| 102 | |||
| 103 | return sym; /* Found */ |
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| 2978 | svoboda | 104 | } |
| 105 | |||
| 2980 | svoboda | 106 | |
| 107 | elf_symbol_t *symbol_def_find(char *name, module_t **m) |
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| 108 | { |
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| 109 | elf_symbol_t *sym; |
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| 110 | |||
| 111 | sym = def_find_in_module(name, runtime_env.program); |
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| 112 | if (sym != NULL) { *m = runtime_env.program; return sym; } |
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| 113 | |||
| 114 | sym = def_find_in_module(name, runtime_env.libc); |
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| 115 | if (sym != NULL) { *m = runtime_env.libc; return sym; } |
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| 116 | |||
| 2981 | svoboda | 117 | sym = def_find_in_module(name, &runtime_env.rtld); |
| 118 | if (sym != NULL) { *m = &runtime_env.rtld; return sym; } |
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| 2980 | svoboda | 119 | |
| 120 | printf("symbol found nowhere\n"); |
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| 121 | *m = NULL; |
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| 122 | return NULL; |
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| 123 | } |
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| 124 | |||
| 2998 | svoboda | 125 | uintptr_t symbol_get_addr(elf_symbol_t *sym, module_t *m) |
| 126 | { |
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| 127 | if (sym->st_shndx == SHN_ABS) { |
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| 128 | /* Do not add bias to absolute symbols */ |
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| 129 | return sym->st_value; |
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| 130 | } else { |
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| 131 | return sym->st_value + m->bias; |
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| 132 | } |
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| 133 | } |
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| 134 | |||
| 2978 | svoboda | 135 | /** @} |
| 136 | */ |