.. | .. |
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| 1 | +// SPDX-License-Identifier: GPL-2.0-or-later |
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1 | 2 | /* |
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2 | 3 | * elf.c - ELF access library |
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3 | 4 | * |
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4 | 5 | * Adapted from kpatch (https://github.com/dynup/kpatch): |
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5 | 6 | * Copyright (C) 2013-2015 Josh Poimboeuf <jpoimboe@redhat.com> |
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6 | 7 | * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com> |
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7 | | - * |
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8 | | - * This program is free software; you can redistribute it and/or |
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9 | | - * modify it under the terms of the GNU General Public License |
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10 | | - * as published by the Free Software Foundation; either version 2 |
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11 | | - * of the License, or (at your option) any later version. |
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12 | | - * |
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13 | | - * This program is distributed in the hope that it will be useful, |
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14 | | - * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | | - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 | | - * GNU General Public License for more details. |
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17 | | - * |
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18 | | - * You should have received a copy of the GNU General Public License |
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19 | | - * along with this program; if not, see <http://www.gnu.org/licenses/>. |
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20 | 8 | */ |
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21 | 9 | |
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22 | 10 | #include <sys/types.h> |
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.. | .. |
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27 | 15 | #include <string.h> |
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28 | 16 | #include <unistd.h> |
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29 | 17 | #include <errno.h> |
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| 18 | +#include "builtin.h" |
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30 | 19 | |
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31 | 20 | #include "elf.h" |
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32 | 21 | #include "warn.h" |
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33 | 22 | |
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34 | 23 | #define MAX_NAME_LEN 128 |
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35 | 24 | |
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36 | | -struct section *find_section_by_name(struct elf *elf, const char *name) |
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| 25 | +static inline u32 str_hash(const char *str) |
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| 26 | +{ |
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| 27 | + return jhash(str, strlen(str), 0); |
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| 28 | +} |
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| 29 | + |
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| 30 | +static inline int elf_hash_bits(void) |
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| 31 | +{ |
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| 32 | + return vmlinux ? ELF_HASH_BITS : 16; |
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| 33 | +} |
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| 34 | + |
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| 35 | +#define elf_hash_add(hashtable, node, key) \ |
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| 36 | + hlist_add_head(node, &hashtable[hash_min(key, elf_hash_bits())]) |
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| 37 | + |
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| 38 | +static void elf_hash_init(struct hlist_head *table) |
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| 39 | +{ |
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| 40 | + __hash_init(table, 1U << elf_hash_bits()); |
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| 41 | +} |
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| 42 | + |
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| 43 | +#define elf_hash_for_each_possible(name, obj, member, key) \ |
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| 44 | + hlist_for_each_entry(obj, &name[hash_min(key, elf_hash_bits())], member) |
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| 45 | + |
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| 46 | +static void rb_add(struct rb_root *tree, struct rb_node *node, |
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| 47 | + int (*cmp)(struct rb_node *, const struct rb_node *)) |
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| 48 | +{ |
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| 49 | + struct rb_node **link = &tree->rb_node; |
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| 50 | + struct rb_node *parent = NULL; |
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| 51 | + |
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| 52 | + while (*link) { |
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| 53 | + parent = *link; |
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| 54 | + if (cmp(node, parent) < 0) |
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| 55 | + link = &parent->rb_left; |
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| 56 | + else |
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| 57 | + link = &parent->rb_right; |
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| 58 | + } |
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| 59 | + |
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| 60 | + rb_link_node(node, parent, link); |
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| 61 | + rb_insert_color(node, tree); |
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| 62 | +} |
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| 63 | + |
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| 64 | +static struct rb_node *rb_find_first(const struct rb_root *tree, const void *key, |
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| 65 | + int (*cmp)(const void *key, const struct rb_node *)) |
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| 66 | +{ |
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| 67 | + struct rb_node *node = tree->rb_node; |
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| 68 | + struct rb_node *match = NULL; |
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| 69 | + |
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| 70 | + while (node) { |
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| 71 | + int c = cmp(key, node); |
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| 72 | + if (c <= 0) { |
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| 73 | + if (!c) |
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| 74 | + match = node; |
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| 75 | + node = node->rb_left; |
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| 76 | + } else if (c > 0) { |
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| 77 | + node = node->rb_right; |
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| 78 | + } |
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| 79 | + } |
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| 80 | + |
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| 81 | + return match; |
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| 82 | +} |
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| 83 | + |
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| 84 | +static struct rb_node *rb_next_match(struct rb_node *node, const void *key, |
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| 85 | + int (*cmp)(const void *key, const struct rb_node *)) |
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| 86 | +{ |
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| 87 | + node = rb_next(node); |
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| 88 | + if (node && cmp(key, node)) |
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| 89 | + node = NULL; |
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| 90 | + return node; |
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| 91 | +} |
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| 92 | + |
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| 93 | +#define rb_for_each(tree, node, key, cmp) \ |
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| 94 | + for ((node) = rb_find_first((tree), (key), (cmp)); \ |
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| 95 | + (node); (node) = rb_next_match((node), (key), (cmp))) |
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| 96 | + |
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| 97 | +static int symbol_to_offset(struct rb_node *a, const struct rb_node *b) |
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| 98 | +{ |
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| 99 | + struct symbol *sa = rb_entry(a, struct symbol, node); |
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| 100 | + struct symbol *sb = rb_entry(b, struct symbol, node); |
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| 101 | + |
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| 102 | + if (sa->offset < sb->offset) |
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| 103 | + return -1; |
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| 104 | + if (sa->offset > sb->offset) |
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| 105 | + return 1; |
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| 106 | + |
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| 107 | + if (sa->len < sb->len) |
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| 108 | + return -1; |
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| 109 | + if (sa->len > sb->len) |
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| 110 | + return 1; |
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| 111 | + |
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| 112 | + sa->alias = sb; |
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| 113 | + |
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| 114 | + return 0; |
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| 115 | +} |
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| 116 | + |
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| 117 | +static int symbol_by_offset(const void *key, const struct rb_node *node) |
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| 118 | +{ |
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| 119 | + const struct symbol *s = rb_entry(node, struct symbol, node); |
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| 120 | + const unsigned long *o = key; |
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| 121 | + |
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| 122 | + if (*o < s->offset) |
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| 123 | + return -1; |
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| 124 | + if (*o >= s->offset + s->len) |
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| 125 | + return 1; |
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| 126 | + |
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| 127 | + return 0; |
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| 128 | +} |
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| 129 | + |
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| 130 | +struct section *find_section_by_name(const struct elf *elf, const char *name) |
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37 | 131 | { |
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38 | 132 | struct section *sec; |
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39 | 133 | |
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40 | | - list_for_each_entry(sec, &elf->sections, list) |
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| 134 | + elf_hash_for_each_possible(elf->section_name_hash, sec, name_hash, str_hash(name)) |
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41 | 135 | if (!strcmp(sec->name, name)) |
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42 | 136 | return sec; |
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43 | 137 | |
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.. | .. |
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49 | 143 | { |
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50 | 144 | struct section *sec; |
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51 | 145 | |
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52 | | - list_for_each_entry(sec, &elf->sections, list) |
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| 146 | + elf_hash_for_each_possible(elf->section_hash, sec, hash, idx) |
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53 | 147 | if (sec->idx == idx) |
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54 | 148 | return sec; |
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55 | 149 | |
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.. | .. |
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58 | 152 | |
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59 | 153 | static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx) |
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60 | 154 | { |
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61 | | - struct section *sec; |
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62 | 155 | struct symbol *sym; |
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63 | 156 | |
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64 | | - list_for_each_entry(sec, &elf->sections, list) |
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65 | | - hash_for_each_possible(sec->symbol_hash, sym, hash, idx) |
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66 | | - if (sym->idx == idx) |
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67 | | - return sym; |
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| 157 | + elf_hash_for_each_possible(elf->symbol_hash, sym, hash, idx) |
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| 158 | + if (sym->idx == idx) |
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| 159 | + return sym; |
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68 | 160 | |
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69 | 161 | return NULL; |
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70 | 162 | } |
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71 | 163 | |
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72 | 164 | struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset) |
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73 | 165 | { |
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| 166 | + struct rb_node *node; |
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| 167 | + |
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| 168 | + rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) { |
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| 169 | + struct symbol *s = rb_entry(node, struct symbol, node); |
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| 170 | + |
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| 171 | + if (s->offset == offset && s->type != STT_SECTION) |
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| 172 | + return s; |
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| 173 | + } |
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| 174 | + |
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| 175 | + return NULL; |
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| 176 | +} |
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| 177 | + |
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| 178 | +struct symbol *find_func_by_offset(struct section *sec, unsigned long offset) |
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| 179 | +{ |
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| 180 | + struct rb_node *node; |
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| 181 | + |
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| 182 | + rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) { |
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| 183 | + struct symbol *s = rb_entry(node, struct symbol, node); |
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| 184 | + |
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| 185 | + if (s->offset == offset && s->type == STT_FUNC) |
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| 186 | + return s; |
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| 187 | + } |
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| 188 | + |
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| 189 | + return NULL; |
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| 190 | +} |
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| 191 | + |
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| 192 | +struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset) |
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| 193 | +{ |
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| 194 | + struct rb_node *node; |
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| 195 | + |
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| 196 | + rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) { |
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| 197 | + struct symbol *s = rb_entry(node, struct symbol, node); |
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| 198 | + |
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| 199 | + if (s->type != STT_SECTION) |
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| 200 | + return s; |
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| 201 | + } |
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| 202 | + |
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| 203 | + return NULL; |
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| 204 | +} |
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| 205 | + |
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| 206 | +struct symbol *find_func_containing(struct section *sec, unsigned long offset) |
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| 207 | +{ |
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| 208 | + struct rb_node *node; |
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| 209 | + |
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| 210 | + rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) { |
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| 211 | + struct symbol *s = rb_entry(node, struct symbol, node); |
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| 212 | + |
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| 213 | + if (s->type == STT_FUNC) |
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| 214 | + return s; |
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| 215 | + } |
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| 216 | + |
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| 217 | + return NULL; |
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| 218 | +} |
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| 219 | + |
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| 220 | +struct symbol *find_symbol_by_name(const struct elf *elf, const char *name) |
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| 221 | +{ |
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74 | 222 | struct symbol *sym; |
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75 | 223 | |
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76 | | - list_for_each_entry(sym, &sec->symbol_list, list) |
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77 | | - if (sym->type != STT_SECTION && |
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78 | | - sym->offset == offset) |
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| 224 | + elf_hash_for_each_possible(elf->symbol_name_hash, sym, name_hash, str_hash(name)) |
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| 225 | + if (!strcmp(sym->name, name)) |
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79 | 226 | return sym; |
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80 | 227 | |
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81 | 228 | return NULL; |
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82 | 229 | } |
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83 | 230 | |
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84 | | -struct symbol *find_symbol_by_name(struct elf *elf, const char *name) |
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| 231 | +struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec, |
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| 232 | + unsigned long offset, unsigned int len) |
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85 | 233 | { |
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86 | | - struct section *sec; |
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87 | | - struct symbol *sym; |
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88 | | - |
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89 | | - list_for_each_entry(sec, &elf->sections, list) |
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90 | | - list_for_each_entry(sym, &sec->symbol_list, list) |
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91 | | - if (!strcmp(sym->name, name)) |
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92 | | - return sym; |
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93 | | - |
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94 | | - return NULL; |
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95 | | -} |
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96 | | - |
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97 | | -struct symbol *find_symbol_containing(struct section *sec, unsigned long offset) |
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98 | | -{ |
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99 | | - struct symbol *sym; |
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100 | | - |
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101 | | - list_for_each_entry(sym, &sec->symbol_list, list) |
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102 | | - if (sym->type != STT_SECTION && |
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103 | | - offset >= sym->offset && offset < sym->offset + sym->len) |
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104 | | - return sym; |
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105 | | - |
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106 | | - return NULL; |
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107 | | -} |
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108 | | - |
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109 | | -struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset, |
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110 | | - unsigned int len) |
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111 | | -{ |
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112 | | - struct rela *rela; |
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| 234 | + struct reloc *reloc, *r = NULL; |
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113 | 235 | unsigned long o; |
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114 | 236 | |
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115 | | - if (!sec->rela) |
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| 237 | + if (!sec->reloc) |
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116 | 238 | return NULL; |
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117 | 239 | |
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118 | | - for (o = offset; o < offset + len; o++) |
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119 | | - hash_for_each_possible(sec->rela->rela_hash, rela, hash, o) |
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120 | | - if (rela->offset == o) |
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121 | | - return rela; |
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| 240 | + sec = sec->reloc; |
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| 241 | + |
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| 242 | + for_offset_range(o, offset, offset + len) { |
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| 243 | + elf_hash_for_each_possible(elf->reloc_hash, reloc, hash, |
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| 244 | + sec_offset_hash(sec, o)) { |
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| 245 | + if (reloc->sec != sec) |
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| 246 | + continue; |
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| 247 | + |
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| 248 | + if (reloc->offset >= offset && reloc->offset < offset + len) { |
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| 249 | + if (!r || reloc->offset < r->offset) |
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| 250 | + r = reloc; |
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| 251 | + } |
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| 252 | + } |
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| 253 | + if (r) |
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| 254 | + return r; |
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| 255 | + } |
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122 | 256 | |
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123 | 257 | return NULL; |
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124 | 258 | } |
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125 | 259 | |
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126 | | -struct rela *find_rela_by_dest(struct section *sec, unsigned long offset) |
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| 260 | +struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset) |
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127 | 261 | { |
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128 | | - return find_rela_by_dest_range(sec, offset, 1); |
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129 | | -} |
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130 | | - |
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131 | | -struct symbol *find_containing_func(struct section *sec, unsigned long offset) |
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132 | | -{ |
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133 | | - struct symbol *func; |
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134 | | - |
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135 | | - list_for_each_entry(func, &sec->symbol_list, list) |
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136 | | - if (func->type == STT_FUNC && offset >= func->offset && |
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137 | | - offset < func->offset + func->len) |
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138 | | - return func; |
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139 | | - |
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140 | | - return NULL; |
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| 262 | + return find_reloc_by_dest_range(elf, sec, offset, 1); |
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141 | 263 | } |
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142 | 264 | |
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143 | 265 | static int read_sections(struct elf *elf) |
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.. | .. |
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166 | 288 | memset(sec, 0, sizeof(*sec)); |
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167 | 289 | |
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168 | 290 | INIT_LIST_HEAD(&sec->symbol_list); |
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169 | | - INIT_LIST_HEAD(&sec->rela_list); |
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170 | | - hash_init(sec->rela_hash); |
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171 | | - hash_init(sec->symbol_hash); |
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172 | | - |
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173 | | - list_add_tail(&sec->list, &elf->sections); |
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| 291 | + INIT_LIST_HEAD(&sec->reloc_list); |
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174 | 292 | |
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175 | 293 | s = elf_getscn(elf->elf, i); |
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176 | 294 | if (!s) { |
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.. | .. |
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205 | 323 | } |
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206 | 324 | } |
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207 | 325 | sec->len = sec->sh.sh_size; |
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| 326 | + |
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| 327 | + list_add_tail(&sec->list, &elf->sections); |
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| 328 | + elf_hash_add(elf->section_hash, &sec->hash, sec->idx); |
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| 329 | + elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); |
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208 | 330 | } |
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| 331 | + |
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| 332 | + if (stats) |
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| 333 | + printf("nr_sections: %lu\n", (unsigned long)sections_nr); |
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209 | 334 | |
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210 | 335 | /* sanity check, one more call to elf_nextscn() should return NULL */ |
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211 | 336 | if (elf_nextscn(elf->elf, s)) { |
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.. | .. |
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216 | 341 | return 0; |
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217 | 342 | } |
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218 | 343 | |
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| 344 | +static void elf_add_symbol(struct elf *elf, struct symbol *sym) |
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| 345 | +{ |
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| 346 | + struct list_head *entry; |
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| 347 | + struct rb_node *pnode; |
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| 348 | + |
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| 349 | + sym->alias = sym; |
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| 350 | + |
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| 351 | + sym->type = GELF_ST_TYPE(sym->sym.st_info); |
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| 352 | + sym->bind = GELF_ST_BIND(sym->sym.st_info); |
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| 353 | + |
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| 354 | + sym->offset = sym->sym.st_value; |
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| 355 | + sym->len = sym->sym.st_size; |
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| 356 | + |
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| 357 | + rb_add(&sym->sec->symbol_tree, &sym->node, symbol_to_offset); |
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| 358 | + pnode = rb_prev(&sym->node); |
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| 359 | + if (pnode) |
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| 360 | + entry = &rb_entry(pnode, struct symbol, node)->list; |
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| 361 | + else |
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| 362 | + entry = &sym->sec->symbol_list; |
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| 363 | + list_add(&sym->list, entry); |
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| 364 | + elf_hash_add(elf->symbol_hash, &sym->hash, sym->idx); |
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| 365 | + elf_hash_add(elf->symbol_name_hash, &sym->name_hash, str_hash(sym->name)); |
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| 366 | + |
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| 367 | + /* |
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| 368 | + * Don't store empty STT_NOTYPE symbols in the rbtree. They |
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| 369 | + * can exist within a function, confusing the sorting. |
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| 370 | + */ |
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| 371 | + if (!sym->len) |
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| 372 | + rb_erase(&sym->node, &sym->sec->symbol_tree); |
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| 373 | +} |
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| 374 | + |
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219 | 375 | static int read_symbols(struct elf *elf) |
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220 | 376 | { |
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221 | | - struct section *symtab, *sec; |
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| 377 | + struct section *symtab, *symtab_shndx, *sec; |
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222 | 378 | struct symbol *sym, *pfunc; |
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223 | | - struct list_head *entry, *tmp; |
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224 | 379 | int symbols_nr, i; |
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225 | 380 | char *coldstr; |
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| 381 | + Elf_Data *shndx_data = NULL; |
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| 382 | + Elf32_Word shndx; |
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226 | 383 | |
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227 | 384 | symtab = find_section_by_name(elf, ".symtab"); |
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228 | 385 | if (!symtab) { |
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.. | .. |
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232 | 389 | */ |
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233 | 390 | return 0; |
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234 | 391 | } |
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| 392 | + |
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| 393 | + symtab_shndx = find_section_by_name(elf, ".symtab_shndx"); |
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| 394 | + if (symtab_shndx) |
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| 395 | + shndx_data = symtab_shndx->data; |
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235 | 396 | |
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236 | 397 | symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize; |
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237 | 398 | |
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.. | .. |
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245 | 406 | |
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246 | 407 | sym->idx = i; |
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247 | 408 | |
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248 | | - if (!gelf_getsym(symtab->data, i, &sym->sym)) { |
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249 | | - WARN_ELF("gelf_getsym"); |
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| 409 | + if (!gelf_getsymshndx(symtab->data, shndx_data, i, &sym->sym, |
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| 410 | + &shndx)) { |
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| 411 | + WARN_ELF("gelf_getsymshndx"); |
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250 | 412 | goto err; |
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251 | 413 | } |
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252 | 414 | |
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.. | .. |
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257 | 419 | goto err; |
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258 | 420 | } |
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259 | 421 | |
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260 | | - sym->type = GELF_ST_TYPE(sym->sym.st_info); |
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261 | | - sym->bind = GELF_ST_BIND(sym->sym.st_info); |
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| 422 | + if ((sym->sym.st_shndx > SHN_UNDEF && |
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| 423 | + sym->sym.st_shndx < SHN_LORESERVE) || |
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| 424 | + (shndx_data && sym->sym.st_shndx == SHN_XINDEX)) { |
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| 425 | + if (sym->sym.st_shndx != SHN_XINDEX) |
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| 426 | + shndx = sym->sym.st_shndx; |
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262 | 427 | |
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263 | | - if (sym->sym.st_shndx > SHN_UNDEF && |
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264 | | - sym->sym.st_shndx < SHN_LORESERVE) { |
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265 | | - sym->sec = find_section_by_index(elf, |
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266 | | - sym->sym.st_shndx); |
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| 428 | + sym->sec = find_section_by_index(elf, shndx); |
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267 | 429 | if (!sym->sec) { |
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268 | 430 | WARN("couldn't find section for symbol %s", |
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269 | 431 | sym->name); |
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270 | 432 | goto err; |
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271 | 433 | } |
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272 | | - if (sym->type == STT_SECTION) { |
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| 434 | + if (GELF_ST_TYPE(sym->sym.st_info) == STT_SECTION) { |
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273 | 435 | sym->name = sym->sec->name; |
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274 | 436 | sym->sec->sym = sym; |
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275 | 437 | } |
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276 | 438 | } else |
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277 | 439 | sym->sec = find_section_by_index(elf, 0); |
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278 | 440 | |
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279 | | - sym->offset = sym->sym.st_value; |
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280 | | - sym->len = sym->sym.st_size; |
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281 | | - |
---|
282 | | - /* sorted insert into a per-section list */ |
---|
283 | | - entry = &sym->sec->symbol_list; |
---|
284 | | - list_for_each_prev(tmp, &sym->sec->symbol_list) { |
---|
285 | | - struct symbol *s; |
---|
286 | | - |
---|
287 | | - s = list_entry(tmp, struct symbol, list); |
---|
288 | | - |
---|
289 | | - if (sym->offset > s->offset) { |
---|
290 | | - entry = tmp; |
---|
291 | | - break; |
---|
292 | | - } |
---|
293 | | - |
---|
294 | | - if (sym->offset == s->offset && sym->len >= s->len) { |
---|
295 | | - entry = tmp; |
---|
296 | | - break; |
---|
297 | | - } |
---|
298 | | - } |
---|
299 | | - list_add(&sym->list, entry); |
---|
300 | | - hash_add(sym->sec->symbol_hash, &sym->hash, sym->idx); |
---|
| 441 | + elf_add_symbol(elf, sym); |
---|
301 | 442 | } |
---|
| 443 | + |
---|
| 444 | + if (stats) |
---|
| 445 | + printf("nr_symbols: %lu\n", (unsigned long)symbols_nr); |
---|
302 | 446 | |
---|
303 | 447 | /* Create parent/child links for any cold subfunctions */ |
---|
304 | 448 | list_for_each_entry(sec, &elf->sections, list) { |
---|
.. | .. |
---|
307 | 451 | size_t pnamelen; |
---|
308 | 452 | if (sym->type != STT_FUNC) |
---|
309 | 453 | continue; |
---|
310 | | - sym->pfunc = sym->cfunc = sym; |
---|
| 454 | + |
---|
| 455 | + if (sym->pfunc == NULL) |
---|
| 456 | + sym->pfunc = sym; |
---|
| 457 | + |
---|
| 458 | + if (sym->cfunc == NULL) |
---|
| 459 | + sym->cfunc = sym; |
---|
| 460 | + |
---|
311 | 461 | coldstr = strstr(sym->name, ".cold"); |
---|
312 | 462 | if (!coldstr) |
---|
313 | 463 | continue; |
---|
.. | .. |
---|
355 | 505 | return -1; |
---|
356 | 506 | } |
---|
357 | 507 | |
---|
358 | | -static int read_relas(struct elf *elf) |
---|
| 508 | +static struct section *elf_create_reloc_section(struct elf *elf, |
---|
| 509 | + struct section *base, |
---|
| 510 | + int reltype); |
---|
| 511 | + |
---|
| 512 | +int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset, |
---|
| 513 | + unsigned int type, struct symbol *sym, s64 addend) |
---|
| 514 | +{ |
---|
| 515 | + struct reloc *reloc; |
---|
| 516 | + |
---|
| 517 | + if (!sec->reloc && !elf_create_reloc_section(elf, sec, SHT_RELA)) |
---|
| 518 | + return -1; |
---|
| 519 | + |
---|
| 520 | + reloc = malloc(sizeof(*reloc)); |
---|
| 521 | + if (!reloc) { |
---|
| 522 | + perror("malloc"); |
---|
| 523 | + return -1; |
---|
| 524 | + } |
---|
| 525 | + memset(reloc, 0, sizeof(*reloc)); |
---|
| 526 | + |
---|
| 527 | + reloc->sec = sec->reloc; |
---|
| 528 | + reloc->offset = offset; |
---|
| 529 | + reloc->type = type; |
---|
| 530 | + reloc->sym = sym; |
---|
| 531 | + reloc->addend = addend; |
---|
| 532 | + |
---|
| 533 | + list_add_tail(&reloc->list, &sec->reloc->reloc_list); |
---|
| 534 | + elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc)); |
---|
| 535 | + |
---|
| 536 | + sec->reloc->changed = true; |
---|
| 537 | + |
---|
| 538 | + return 0; |
---|
| 539 | +} |
---|
| 540 | + |
---|
| 541 | +/* |
---|
| 542 | + * Ensure that any reloc section containing references to @sym is marked |
---|
| 543 | + * changed such that it will get re-generated in elf_rebuild_reloc_sections() |
---|
| 544 | + * with the new symbol index. |
---|
| 545 | + */ |
---|
| 546 | +static void elf_dirty_reloc_sym(struct elf *elf, struct symbol *sym) |
---|
359 | 547 | { |
---|
360 | 548 | struct section *sec; |
---|
361 | | - struct rela *rela; |
---|
362 | | - int i; |
---|
363 | | - unsigned int symndx; |
---|
364 | 549 | |
---|
365 | 550 | list_for_each_entry(sec, &elf->sections, list) { |
---|
366 | | - if (sec->sh.sh_type != SHT_RELA) |
---|
| 551 | + struct reloc *reloc; |
---|
| 552 | + |
---|
| 553 | + if (sec->changed) |
---|
367 | 554 | continue; |
---|
368 | 555 | |
---|
369 | | - sec->base = find_section_by_name(elf, sec->name + 5); |
---|
370 | | - if (!sec->base) { |
---|
371 | | - WARN("can't find base section for rela section %s", |
---|
372 | | - sec->name); |
---|
| 556 | + list_for_each_entry(reloc, &sec->reloc_list, list) { |
---|
| 557 | + if (reloc->sym == sym) { |
---|
| 558 | + sec->changed = true; |
---|
| 559 | + break; |
---|
| 560 | + } |
---|
| 561 | + } |
---|
| 562 | + } |
---|
| 563 | +} |
---|
| 564 | + |
---|
| 565 | +/* |
---|
| 566 | + * The libelf API is terrible; gelf_update_sym*() takes a data block relative |
---|
| 567 | + * index value, *NOT* the symbol index. As such, iterate the data blocks and |
---|
| 568 | + * adjust index until it fits. |
---|
| 569 | + * |
---|
| 570 | + * If no data block is found, allow adding a new data block provided the index |
---|
| 571 | + * is only one past the end. |
---|
| 572 | + */ |
---|
| 573 | +static int elf_update_symbol(struct elf *elf, struct section *symtab, |
---|
| 574 | + struct section *symtab_shndx, struct symbol *sym) |
---|
| 575 | +{ |
---|
| 576 | + Elf32_Word shndx = sym->sec ? sym->sec->idx : SHN_UNDEF; |
---|
| 577 | + Elf_Data *symtab_data = NULL, *shndx_data = NULL; |
---|
| 578 | + Elf64_Xword entsize = symtab->sh.sh_entsize; |
---|
| 579 | + int max_idx, idx = sym->idx; |
---|
| 580 | + Elf_Scn *s, *t = NULL; |
---|
| 581 | + bool is_special_shndx = sym->sym.st_shndx >= SHN_LORESERVE && |
---|
| 582 | + sym->sym.st_shndx != SHN_XINDEX; |
---|
| 583 | + |
---|
| 584 | + if (is_special_shndx) |
---|
| 585 | + shndx = sym->sym.st_shndx; |
---|
| 586 | + |
---|
| 587 | + s = elf_getscn(elf->elf, symtab->idx); |
---|
| 588 | + if (!s) { |
---|
| 589 | + WARN_ELF("elf_getscn"); |
---|
| 590 | + return -1; |
---|
| 591 | + } |
---|
| 592 | + |
---|
| 593 | + if (symtab_shndx) { |
---|
| 594 | + t = elf_getscn(elf->elf, symtab_shndx->idx); |
---|
| 595 | + if (!t) { |
---|
| 596 | + WARN_ELF("elf_getscn"); |
---|
| 597 | + return -1; |
---|
| 598 | + } |
---|
| 599 | + } |
---|
| 600 | + |
---|
| 601 | + for (;;) { |
---|
| 602 | + /* get next data descriptor for the relevant sections */ |
---|
| 603 | + symtab_data = elf_getdata(s, symtab_data); |
---|
| 604 | + if (t) |
---|
| 605 | + shndx_data = elf_getdata(t, shndx_data); |
---|
| 606 | + |
---|
| 607 | + /* end-of-list */ |
---|
| 608 | + if (!symtab_data) { |
---|
| 609 | + void *buf; |
---|
| 610 | + |
---|
| 611 | + if (idx) { |
---|
| 612 | + /* we don't do holes in symbol tables */ |
---|
| 613 | + WARN("index out of range"); |
---|
| 614 | + return -1; |
---|
| 615 | + } |
---|
| 616 | + |
---|
| 617 | + /* if @idx == 0, it's the next contiguous entry, create it */ |
---|
| 618 | + symtab_data = elf_newdata(s); |
---|
| 619 | + if (t) |
---|
| 620 | + shndx_data = elf_newdata(t); |
---|
| 621 | + |
---|
| 622 | + buf = calloc(1, entsize); |
---|
| 623 | + if (!buf) { |
---|
| 624 | + WARN("malloc"); |
---|
| 625 | + return -1; |
---|
| 626 | + } |
---|
| 627 | + |
---|
| 628 | + symtab_data->d_buf = buf; |
---|
| 629 | + symtab_data->d_size = entsize; |
---|
| 630 | + symtab_data->d_align = 1; |
---|
| 631 | + symtab_data->d_type = ELF_T_SYM; |
---|
| 632 | + |
---|
| 633 | + symtab->sh.sh_size += entsize; |
---|
| 634 | + symtab->changed = true; |
---|
| 635 | + |
---|
| 636 | + if (t) { |
---|
| 637 | + shndx_data->d_buf = &sym->sec->idx; |
---|
| 638 | + shndx_data->d_size = sizeof(Elf32_Word); |
---|
| 639 | + shndx_data->d_align = sizeof(Elf32_Word); |
---|
| 640 | + shndx_data->d_type = ELF_T_WORD; |
---|
| 641 | + |
---|
| 642 | + symtab_shndx->sh.sh_size += sizeof(Elf32_Word); |
---|
| 643 | + symtab_shndx->changed = true; |
---|
| 644 | + } |
---|
| 645 | + |
---|
| 646 | + break; |
---|
| 647 | + } |
---|
| 648 | + |
---|
| 649 | + /* empty blocks should not happen */ |
---|
| 650 | + if (!symtab_data->d_size) { |
---|
| 651 | + WARN("zero size data"); |
---|
373 | 652 | return -1; |
---|
374 | 653 | } |
---|
375 | 654 | |
---|
376 | | - sec->base->rela = sec; |
---|
| 655 | + /* is this the right block? */ |
---|
| 656 | + max_idx = symtab_data->d_size / entsize; |
---|
| 657 | + if (idx < max_idx) |
---|
| 658 | + break; |
---|
377 | 659 | |
---|
378 | | - for (i = 0; i < sec->sh.sh_size / sec->sh.sh_entsize; i++) { |
---|
379 | | - rela = malloc(sizeof(*rela)); |
---|
380 | | - if (!rela) { |
---|
381 | | - perror("malloc"); |
---|
382 | | - return -1; |
---|
383 | | - } |
---|
384 | | - memset(rela, 0, sizeof(*rela)); |
---|
| 660 | + /* adjust index and try again */ |
---|
| 661 | + idx -= max_idx; |
---|
| 662 | + } |
---|
385 | 663 | |
---|
386 | | - if (!gelf_getrela(sec->data, i, &rela->rela)) { |
---|
387 | | - WARN_ELF("gelf_getrela"); |
---|
388 | | - return -1; |
---|
389 | | - } |
---|
| 664 | + /* something went side-ways */ |
---|
| 665 | + if (idx < 0) { |
---|
| 666 | + WARN("negative index"); |
---|
| 667 | + return -1; |
---|
| 668 | + } |
---|
390 | 669 | |
---|
391 | | - rela->type = GELF_R_TYPE(rela->rela.r_info); |
---|
392 | | - rela->addend = rela->rela.r_addend; |
---|
393 | | - rela->offset = rela->rela.r_offset; |
---|
394 | | - symndx = GELF_R_SYM(rela->rela.r_info); |
---|
395 | | - rela->sym = find_symbol_by_index(elf, symndx); |
---|
396 | | - rela->rela_sec = sec; |
---|
397 | | - if (!rela->sym) { |
---|
398 | | - WARN("can't find rela entry symbol %d for %s", |
---|
399 | | - symndx, sec->name); |
---|
400 | | - return -1; |
---|
401 | | - } |
---|
402 | | - |
---|
403 | | - list_add_tail(&rela->list, &sec->rela_list); |
---|
404 | | - hash_add(sec->rela_hash, &rela->hash, rela->offset); |
---|
405 | | - |
---|
| 670 | + /* setup extended section index magic and write the symbol */ |
---|
| 671 | + if ((shndx >= SHN_UNDEF && shndx < SHN_LORESERVE) || is_special_shndx) { |
---|
| 672 | + sym->sym.st_shndx = shndx; |
---|
| 673 | + if (!shndx_data) |
---|
| 674 | + shndx = 0; |
---|
| 675 | + } else { |
---|
| 676 | + sym->sym.st_shndx = SHN_XINDEX; |
---|
| 677 | + if (!shndx_data) { |
---|
| 678 | + WARN("no .symtab_shndx"); |
---|
| 679 | + return -1; |
---|
406 | 680 | } |
---|
| 681 | + } |
---|
| 682 | + |
---|
| 683 | + if (!gelf_update_symshndx(symtab_data, shndx_data, idx, &sym->sym, shndx)) { |
---|
| 684 | + WARN_ELF("gelf_update_symshndx"); |
---|
| 685 | + return -1; |
---|
407 | 686 | } |
---|
408 | 687 | |
---|
409 | 688 | return 0; |
---|
410 | 689 | } |
---|
411 | 690 | |
---|
412 | | -struct elf *elf_open(const char *name, int flags) |
---|
| 691 | +static struct symbol * |
---|
| 692 | +elf_create_section_symbol(struct elf *elf, struct section *sec) |
---|
| 693 | +{ |
---|
| 694 | + struct section *symtab, *symtab_shndx; |
---|
| 695 | + Elf32_Word first_non_local, new_idx; |
---|
| 696 | + struct symbol *sym, *old; |
---|
| 697 | + |
---|
| 698 | + symtab = find_section_by_name(elf, ".symtab"); |
---|
| 699 | + if (symtab) { |
---|
| 700 | + symtab_shndx = find_section_by_name(elf, ".symtab_shndx"); |
---|
| 701 | + } else { |
---|
| 702 | + WARN("no .symtab"); |
---|
| 703 | + return NULL; |
---|
| 704 | + } |
---|
| 705 | + |
---|
| 706 | + sym = calloc(1, sizeof(*sym)); |
---|
| 707 | + if (!sym) { |
---|
| 708 | + perror("malloc"); |
---|
| 709 | + return NULL; |
---|
| 710 | + } |
---|
| 711 | + |
---|
| 712 | + sym->name = sec->name; |
---|
| 713 | + sym->sec = sec; |
---|
| 714 | + |
---|
| 715 | + // st_name 0 |
---|
| 716 | + sym->sym.st_info = GELF_ST_INFO(STB_LOCAL, STT_SECTION); |
---|
| 717 | + // st_other 0 |
---|
| 718 | + // st_value 0 |
---|
| 719 | + // st_size 0 |
---|
| 720 | + |
---|
| 721 | + /* |
---|
| 722 | + * Move the first global symbol, as per sh_info, into a new, higher |
---|
| 723 | + * symbol index. This fees up a spot for a new local symbol. |
---|
| 724 | + */ |
---|
| 725 | + first_non_local = symtab->sh.sh_info; |
---|
| 726 | + new_idx = symtab->sh.sh_size / symtab->sh.sh_entsize; |
---|
| 727 | + old = find_symbol_by_index(elf, first_non_local); |
---|
| 728 | + if (old) { |
---|
| 729 | + old->idx = new_idx; |
---|
| 730 | + |
---|
| 731 | + hlist_del(&old->hash); |
---|
| 732 | + elf_hash_add(elf->symbol_hash, &old->hash, old->idx); |
---|
| 733 | + |
---|
| 734 | + elf_dirty_reloc_sym(elf, old); |
---|
| 735 | + |
---|
| 736 | + if (elf_update_symbol(elf, symtab, symtab_shndx, old)) { |
---|
| 737 | + WARN("elf_update_symbol move"); |
---|
| 738 | + return NULL; |
---|
| 739 | + } |
---|
| 740 | + |
---|
| 741 | + new_idx = first_non_local; |
---|
| 742 | + } |
---|
| 743 | + |
---|
| 744 | + sym->idx = new_idx; |
---|
| 745 | + if (elf_update_symbol(elf, symtab, symtab_shndx, sym)) { |
---|
| 746 | + WARN("elf_update_symbol"); |
---|
| 747 | + return NULL; |
---|
| 748 | + } |
---|
| 749 | + |
---|
| 750 | + /* |
---|
| 751 | + * Either way, we added a LOCAL symbol. |
---|
| 752 | + */ |
---|
| 753 | + symtab->sh.sh_info += 1; |
---|
| 754 | + |
---|
| 755 | + elf_add_symbol(elf, sym); |
---|
| 756 | + |
---|
| 757 | + return sym; |
---|
| 758 | +} |
---|
| 759 | + |
---|
| 760 | +int elf_add_reloc_to_insn(struct elf *elf, struct section *sec, |
---|
| 761 | + unsigned long offset, unsigned int type, |
---|
| 762 | + struct section *insn_sec, unsigned long insn_off) |
---|
| 763 | +{ |
---|
| 764 | + struct symbol *sym = insn_sec->sym; |
---|
| 765 | + int addend = insn_off; |
---|
| 766 | + |
---|
| 767 | + if (!sym) { |
---|
| 768 | + /* |
---|
| 769 | + * Due to how weak functions work, we must use section based |
---|
| 770 | + * relocations. Symbol based relocations would result in the |
---|
| 771 | + * weak and non-weak function annotations being overlaid on the |
---|
| 772 | + * non-weak function after linking. |
---|
| 773 | + */ |
---|
| 774 | + sym = elf_create_section_symbol(elf, insn_sec); |
---|
| 775 | + if (!sym) |
---|
| 776 | + return -1; |
---|
| 777 | + |
---|
| 778 | + insn_sec->sym = sym; |
---|
| 779 | + } |
---|
| 780 | + |
---|
| 781 | + return elf_add_reloc(elf, sec, offset, type, sym, addend); |
---|
| 782 | +} |
---|
| 783 | + |
---|
| 784 | +static int read_rel_reloc(struct section *sec, int i, struct reloc *reloc, unsigned int *symndx) |
---|
| 785 | +{ |
---|
| 786 | + if (!gelf_getrel(sec->data, i, &reloc->rel)) { |
---|
| 787 | + WARN_ELF("gelf_getrel"); |
---|
| 788 | + return -1; |
---|
| 789 | + } |
---|
| 790 | + reloc->type = GELF_R_TYPE(reloc->rel.r_info); |
---|
| 791 | + reloc->addend = 0; |
---|
| 792 | + reloc->offset = reloc->rel.r_offset; |
---|
| 793 | + *symndx = GELF_R_SYM(reloc->rel.r_info); |
---|
| 794 | + return 0; |
---|
| 795 | +} |
---|
| 796 | + |
---|
| 797 | +static int read_rela_reloc(struct section *sec, int i, struct reloc *reloc, unsigned int *symndx) |
---|
| 798 | +{ |
---|
| 799 | + if (!gelf_getrela(sec->data, i, &reloc->rela)) { |
---|
| 800 | + WARN_ELF("gelf_getrela"); |
---|
| 801 | + return -1; |
---|
| 802 | + } |
---|
| 803 | + reloc->type = GELF_R_TYPE(reloc->rela.r_info); |
---|
| 804 | + reloc->addend = reloc->rela.r_addend; |
---|
| 805 | + reloc->offset = reloc->rela.r_offset; |
---|
| 806 | + *symndx = GELF_R_SYM(reloc->rela.r_info); |
---|
| 807 | + return 0; |
---|
| 808 | +} |
---|
| 809 | + |
---|
| 810 | +static int read_relocs(struct elf *elf) |
---|
| 811 | +{ |
---|
| 812 | + struct section *sec; |
---|
| 813 | + struct reloc *reloc; |
---|
| 814 | + int i; |
---|
| 815 | + unsigned int symndx; |
---|
| 816 | + unsigned long nr_reloc, max_reloc = 0, tot_reloc = 0; |
---|
| 817 | + |
---|
| 818 | + list_for_each_entry(sec, &elf->sections, list) { |
---|
| 819 | + if ((sec->sh.sh_type != SHT_RELA) && |
---|
| 820 | + (sec->sh.sh_type != SHT_REL)) |
---|
| 821 | + continue; |
---|
| 822 | + |
---|
| 823 | + sec->base = find_section_by_index(elf, sec->sh.sh_info); |
---|
| 824 | + if (!sec->base) { |
---|
| 825 | + WARN("can't find base section for reloc section %s", |
---|
| 826 | + sec->name); |
---|
| 827 | + return -1; |
---|
| 828 | + } |
---|
| 829 | + |
---|
| 830 | + sec->base->reloc = sec; |
---|
| 831 | + |
---|
| 832 | + nr_reloc = 0; |
---|
| 833 | + for (i = 0; i < sec->sh.sh_size / sec->sh.sh_entsize; i++) { |
---|
| 834 | + reloc = malloc(sizeof(*reloc)); |
---|
| 835 | + if (!reloc) { |
---|
| 836 | + perror("malloc"); |
---|
| 837 | + return -1; |
---|
| 838 | + } |
---|
| 839 | + memset(reloc, 0, sizeof(*reloc)); |
---|
| 840 | + switch (sec->sh.sh_type) { |
---|
| 841 | + case SHT_REL: |
---|
| 842 | + if (read_rel_reloc(sec, i, reloc, &symndx)) |
---|
| 843 | + return -1; |
---|
| 844 | + break; |
---|
| 845 | + case SHT_RELA: |
---|
| 846 | + if (read_rela_reloc(sec, i, reloc, &symndx)) |
---|
| 847 | + return -1; |
---|
| 848 | + break; |
---|
| 849 | + default: return -1; |
---|
| 850 | + } |
---|
| 851 | + |
---|
| 852 | + reloc->sec = sec; |
---|
| 853 | + reloc->idx = i; |
---|
| 854 | + reloc->sym = find_symbol_by_index(elf, symndx); |
---|
| 855 | + if (!reloc->sym) { |
---|
| 856 | + WARN("can't find reloc entry symbol %d for %s", |
---|
| 857 | + symndx, sec->name); |
---|
| 858 | + return -1; |
---|
| 859 | + } |
---|
| 860 | + |
---|
| 861 | + list_add_tail(&reloc->list, &sec->reloc_list); |
---|
| 862 | + elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc)); |
---|
| 863 | + |
---|
| 864 | + nr_reloc++; |
---|
| 865 | + } |
---|
| 866 | + max_reloc = max(max_reloc, nr_reloc); |
---|
| 867 | + tot_reloc += nr_reloc; |
---|
| 868 | + } |
---|
| 869 | + |
---|
| 870 | + if (stats) { |
---|
| 871 | + printf("max_reloc: %lu\n", max_reloc); |
---|
| 872 | + printf("tot_reloc: %lu\n", tot_reloc); |
---|
| 873 | + } |
---|
| 874 | + |
---|
| 875 | + return 0; |
---|
| 876 | +} |
---|
| 877 | + |
---|
| 878 | +struct elf *elf_open_read(const char *name, int flags) |
---|
413 | 879 | { |
---|
414 | 880 | struct elf *elf; |
---|
415 | 881 | Elf_Cmd cmd; |
---|
.. | .. |
---|
421 | 887 | perror("malloc"); |
---|
422 | 888 | return NULL; |
---|
423 | 889 | } |
---|
424 | | - memset(elf, 0, sizeof(*elf)); |
---|
| 890 | + memset(elf, 0, offsetof(struct elf, sections)); |
---|
425 | 891 | |
---|
426 | 892 | INIT_LIST_HEAD(&elf->sections); |
---|
| 893 | + |
---|
| 894 | + elf_hash_init(elf->symbol_hash); |
---|
| 895 | + elf_hash_init(elf->symbol_name_hash); |
---|
| 896 | + elf_hash_init(elf->section_hash); |
---|
| 897 | + elf_hash_init(elf->section_name_hash); |
---|
| 898 | + elf_hash_init(elf->reloc_hash); |
---|
427 | 899 | |
---|
428 | 900 | elf->fd = open(name, flags); |
---|
429 | 901 | if (elf->fd == -1) { |
---|
.. | .. |
---|
456 | 928 | if (read_symbols(elf)) |
---|
457 | 929 | goto err; |
---|
458 | 930 | |
---|
459 | | - if (read_relas(elf)) |
---|
| 931 | + if (read_relocs(elf)) |
---|
460 | 932 | goto err; |
---|
461 | 933 | |
---|
462 | 934 | return elf; |
---|
.. | .. |
---|
466 | 938 | return NULL; |
---|
467 | 939 | } |
---|
468 | 940 | |
---|
| 941 | +static int elf_add_string(struct elf *elf, struct section *strtab, char *str) |
---|
| 942 | +{ |
---|
| 943 | + Elf_Data *data; |
---|
| 944 | + Elf_Scn *s; |
---|
| 945 | + int len; |
---|
| 946 | + |
---|
| 947 | + if (!strtab) |
---|
| 948 | + strtab = find_section_by_name(elf, ".strtab"); |
---|
| 949 | + if (!strtab) { |
---|
| 950 | + WARN("can't find .strtab section"); |
---|
| 951 | + return -1; |
---|
| 952 | + } |
---|
| 953 | + |
---|
| 954 | + s = elf_getscn(elf->elf, strtab->idx); |
---|
| 955 | + if (!s) { |
---|
| 956 | + WARN_ELF("elf_getscn"); |
---|
| 957 | + return -1; |
---|
| 958 | + } |
---|
| 959 | + |
---|
| 960 | + data = elf_newdata(s); |
---|
| 961 | + if (!data) { |
---|
| 962 | + WARN_ELF("elf_newdata"); |
---|
| 963 | + return -1; |
---|
| 964 | + } |
---|
| 965 | + |
---|
| 966 | + data->d_buf = str; |
---|
| 967 | + data->d_size = strlen(str) + 1; |
---|
| 968 | + data->d_align = 1; |
---|
| 969 | + data->d_type = ELF_T_SYM; |
---|
| 970 | + |
---|
| 971 | + len = strtab->len; |
---|
| 972 | + strtab->len += data->d_size; |
---|
| 973 | + strtab->changed = true; |
---|
| 974 | + |
---|
| 975 | + return len; |
---|
| 976 | +} |
---|
| 977 | + |
---|
469 | 978 | struct section *elf_create_section(struct elf *elf, const char *name, |
---|
470 | | - size_t entsize, int nr) |
---|
| 979 | + unsigned int sh_flags, size_t entsize, int nr) |
---|
471 | 980 | { |
---|
472 | 981 | struct section *sec, *shstrtab; |
---|
473 | 982 | size_t size = entsize * nr; |
---|
474 | | - struct Elf_Scn *s; |
---|
475 | | - Elf_Data *data; |
---|
| 983 | + Elf_Scn *s; |
---|
476 | 984 | |
---|
477 | 985 | sec = malloc(sizeof(*sec)); |
---|
478 | 986 | if (!sec) { |
---|
.. | .. |
---|
482 | 990 | memset(sec, 0, sizeof(*sec)); |
---|
483 | 991 | |
---|
484 | 992 | INIT_LIST_HEAD(&sec->symbol_list); |
---|
485 | | - INIT_LIST_HEAD(&sec->rela_list); |
---|
486 | | - hash_init(sec->rela_hash); |
---|
487 | | - hash_init(sec->symbol_hash); |
---|
488 | | - |
---|
489 | | - list_add_tail(&sec->list, &elf->sections); |
---|
| 993 | + INIT_LIST_HEAD(&sec->reloc_list); |
---|
490 | 994 | |
---|
491 | 995 | s = elf_newscn(elf->elf); |
---|
492 | 996 | if (!s) { |
---|
.. | .. |
---|
531 | 1035 | sec->sh.sh_entsize = entsize; |
---|
532 | 1036 | sec->sh.sh_type = SHT_PROGBITS; |
---|
533 | 1037 | sec->sh.sh_addralign = 1; |
---|
534 | | - sec->sh.sh_flags = SHF_ALLOC; |
---|
535 | | - |
---|
| 1038 | + sec->sh.sh_flags = SHF_ALLOC | sh_flags; |
---|
536 | 1039 | |
---|
537 | 1040 | /* Add section name to .shstrtab (or .strtab for Clang) */ |
---|
538 | 1041 | shstrtab = find_section_by_name(elf, ".shstrtab"); |
---|
.. | .. |
---|
542 | 1045 | WARN("can't find .shstrtab or .strtab section"); |
---|
543 | 1046 | return NULL; |
---|
544 | 1047 | } |
---|
545 | | - |
---|
546 | | - s = elf_getscn(elf->elf, shstrtab->idx); |
---|
547 | | - if (!s) { |
---|
548 | | - WARN_ELF("elf_getscn"); |
---|
| 1048 | + sec->sh.sh_name = elf_add_string(elf, shstrtab, sec->name); |
---|
| 1049 | + if (sec->sh.sh_name == -1) |
---|
549 | 1050 | return NULL; |
---|
550 | | - } |
---|
551 | 1051 | |
---|
552 | | - data = elf_newdata(s); |
---|
553 | | - if (!data) { |
---|
554 | | - WARN_ELF("elf_newdata"); |
---|
555 | | - return NULL; |
---|
556 | | - } |
---|
| 1052 | + list_add_tail(&sec->list, &elf->sections); |
---|
| 1053 | + elf_hash_add(elf->section_hash, &sec->hash, sec->idx); |
---|
| 1054 | + elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); |
---|
557 | 1055 | |
---|
558 | | - data->d_buf = sec->name; |
---|
559 | | - data->d_size = strlen(name) + 1; |
---|
560 | | - data->d_align = 1; |
---|
561 | | - |
---|
562 | | - sec->sh.sh_name = shstrtab->len; |
---|
563 | | - |
---|
564 | | - shstrtab->len += strlen(name) + 1; |
---|
565 | | - shstrtab->changed = true; |
---|
| 1056 | + elf->changed = true; |
---|
566 | 1057 | |
---|
567 | 1058 | return sec; |
---|
568 | 1059 | } |
---|
569 | 1060 | |
---|
570 | | -struct section *elf_create_rela_section(struct elf *elf, struct section *base) |
---|
| 1061 | +static struct section *elf_create_rel_reloc_section(struct elf *elf, struct section *base) |
---|
571 | 1062 | { |
---|
572 | | - char *relaname; |
---|
| 1063 | + char *relocname; |
---|
573 | 1064 | struct section *sec; |
---|
574 | 1065 | |
---|
575 | | - relaname = malloc(strlen(base->name) + strlen(".rela") + 1); |
---|
576 | | - if (!relaname) { |
---|
| 1066 | + relocname = malloc(strlen(base->name) + strlen(".rel") + 1); |
---|
| 1067 | + if (!relocname) { |
---|
577 | 1068 | perror("malloc"); |
---|
578 | 1069 | return NULL; |
---|
579 | 1070 | } |
---|
580 | | - strcpy(relaname, ".rela"); |
---|
581 | | - strcat(relaname, base->name); |
---|
| 1071 | + strcpy(relocname, ".rel"); |
---|
| 1072 | + strcat(relocname, base->name); |
---|
582 | 1073 | |
---|
583 | | - sec = elf_create_section(elf, relaname, sizeof(GElf_Rela), 0); |
---|
584 | | - free(relaname); |
---|
| 1074 | + sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rel), 0); |
---|
| 1075 | + free(relocname); |
---|
585 | 1076 | if (!sec) |
---|
586 | 1077 | return NULL; |
---|
587 | 1078 | |
---|
588 | | - base->rela = sec; |
---|
| 1079 | + base->reloc = sec; |
---|
| 1080 | + sec->base = base; |
---|
| 1081 | + |
---|
| 1082 | + sec->sh.sh_type = SHT_REL; |
---|
| 1083 | + sec->sh.sh_addralign = 8; |
---|
| 1084 | + sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx; |
---|
| 1085 | + sec->sh.sh_info = base->idx; |
---|
| 1086 | + sec->sh.sh_flags = SHF_INFO_LINK; |
---|
| 1087 | + |
---|
| 1088 | + return sec; |
---|
| 1089 | +} |
---|
| 1090 | + |
---|
| 1091 | +static struct section *elf_create_rela_reloc_section(struct elf *elf, struct section *base) |
---|
| 1092 | +{ |
---|
| 1093 | + char *relocname; |
---|
| 1094 | + struct section *sec; |
---|
| 1095 | + |
---|
| 1096 | + relocname = malloc(strlen(base->name) + strlen(".rela") + 1); |
---|
| 1097 | + if (!relocname) { |
---|
| 1098 | + perror("malloc"); |
---|
| 1099 | + return NULL; |
---|
| 1100 | + } |
---|
| 1101 | + strcpy(relocname, ".rela"); |
---|
| 1102 | + strcat(relocname, base->name); |
---|
| 1103 | + |
---|
| 1104 | + sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rela), 0); |
---|
| 1105 | + free(relocname); |
---|
| 1106 | + if (!sec) |
---|
| 1107 | + return NULL; |
---|
| 1108 | + |
---|
| 1109 | + base->reloc = sec; |
---|
589 | 1110 | sec->base = base; |
---|
590 | 1111 | |
---|
591 | 1112 | sec->sh.sh_type = SHT_RELA; |
---|
.. | .. |
---|
597 | 1118 | return sec; |
---|
598 | 1119 | } |
---|
599 | 1120 | |
---|
600 | | -int elf_rebuild_rela_section(struct section *sec) |
---|
| 1121 | +static struct section *elf_create_reloc_section(struct elf *elf, |
---|
| 1122 | + struct section *base, |
---|
| 1123 | + int reltype) |
---|
601 | 1124 | { |
---|
602 | | - struct rela *rela; |
---|
603 | | - int nr, idx = 0, size; |
---|
604 | | - GElf_Rela *relas; |
---|
| 1125 | + switch (reltype) { |
---|
| 1126 | + case SHT_REL: return elf_create_rel_reloc_section(elf, base); |
---|
| 1127 | + case SHT_RELA: return elf_create_rela_reloc_section(elf, base); |
---|
| 1128 | + default: return NULL; |
---|
| 1129 | + } |
---|
| 1130 | +} |
---|
605 | 1131 | |
---|
606 | | - nr = 0; |
---|
607 | | - list_for_each_entry(rela, &sec->rela_list, list) |
---|
608 | | - nr++; |
---|
| 1132 | +static int elf_rebuild_rel_reloc_section(struct section *sec, int nr) |
---|
| 1133 | +{ |
---|
| 1134 | + struct reloc *reloc; |
---|
| 1135 | + int idx = 0, size; |
---|
| 1136 | + GElf_Rel *relocs; |
---|
609 | 1137 | |
---|
610 | | - size = nr * sizeof(*relas); |
---|
611 | | - relas = malloc(size); |
---|
612 | | - if (!relas) { |
---|
| 1138 | + /* Allocate a buffer for relocations */ |
---|
| 1139 | + size = nr * sizeof(*relocs); |
---|
| 1140 | + relocs = malloc(size); |
---|
| 1141 | + if (!relocs) { |
---|
613 | 1142 | perror("malloc"); |
---|
614 | 1143 | return -1; |
---|
615 | 1144 | } |
---|
616 | 1145 | |
---|
617 | | - sec->data->d_buf = relas; |
---|
| 1146 | + sec->data->d_buf = relocs; |
---|
618 | 1147 | sec->data->d_size = size; |
---|
619 | 1148 | |
---|
620 | 1149 | sec->sh.sh_size = size; |
---|
621 | 1150 | |
---|
622 | 1151 | idx = 0; |
---|
623 | | - list_for_each_entry(rela, &sec->rela_list, list) { |
---|
624 | | - relas[idx].r_offset = rela->offset; |
---|
625 | | - relas[idx].r_addend = rela->addend; |
---|
626 | | - relas[idx].r_info = GELF_R_INFO(rela->sym->idx, rela->type); |
---|
| 1152 | + list_for_each_entry(reloc, &sec->reloc_list, list) { |
---|
| 1153 | + relocs[idx].r_offset = reloc->offset; |
---|
| 1154 | + relocs[idx].r_info = GELF_R_INFO(reloc->sym->idx, reloc->type); |
---|
627 | 1155 | idx++; |
---|
628 | 1156 | } |
---|
| 1157 | + |
---|
| 1158 | + return 0; |
---|
| 1159 | +} |
---|
| 1160 | + |
---|
| 1161 | +static int elf_rebuild_rela_reloc_section(struct section *sec, int nr) |
---|
| 1162 | +{ |
---|
| 1163 | + struct reloc *reloc; |
---|
| 1164 | + int idx = 0, size; |
---|
| 1165 | + GElf_Rela *relocs; |
---|
| 1166 | + |
---|
| 1167 | + /* Allocate a buffer for relocations with addends */ |
---|
| 1168 | + size = nr * sizeof(*relocs); |
---|
| 1169 | + relocs = malloc(size); |
---|
| 1170 | + if (!relocs) { |
---|
| 1171 | + perror("malloc"); |
---|
| 1172 | + return -1; |
---|
| 1173 | + } |
---|
| 1174 | + |
---|
| 1175 | + sec->data->d_buf = relocs; |
---|
| 1176 | + sec->data->d_size = size; |
---|
| 1177 | + |
---|
| 1178 | + sec->sh.sh_size = size; |
---|
| 1179 | + |
---|
| 1180 | + idx = 0; |
---|
| 1181 | + list_for_each_entry(reloc, &sec->reloc_list, list) { |
---|
| 1182 | + relocs[idx].r_offset = reloc->offset; |
---|
| 1183 | + relocs[idx].r_addend = reloc->addend; |
---|
| 1184 | + relocs[idx].r_info = GELF_R_INFO(reloc->sym->idx, reloc->type); |
---|
| 1185 | + idx++; |
---|
| 1186 | + } |
---|
| 1187 | + |
---|
| 1188 | + return 0; |
---|
| 1189 | +} |
---|
| 1190 | + |
---|
| 1191 | +static int elf_rebuild_reloc_section(struct elf *elf, struct section *sec) |
---|
| 1192 | +{ |
---|
| 1193 | + struct reloc *reloc; |
---|
| 1194 | + int nr; |
---|
| 1195 | + |
---|
| 1196 | + nr = 0; |
---|
| 1197 | + list_for_each_entry(reloc, &sec->reloc_list, list) |
---|
| 1198 | + nr++; |
---|
| 1199 | + |
---|
| 1200 | + switch (sec->sh.sh_type) { |
---|
| 1201 | + case SHT_REL: return elf_rebuild_rel_reloc_section(sec, nr); |
---|
| 1202 | + case SHT_RELA: return elf_rebuild_rela_reloc_section(sec, nr); |
---|
| 1203 | + default: return -1; |
---|
| 1204 | + } |
---|
| 1205 | +} |
---|
| 1206 | + |
---|
| 1207 | +int elf_write_insn(struct elf *elf, struct section *sec, |
---|
| 1208 | + unsigned long offset, unsigned int len, |
---|
| 1209 | + const char *insn) |
---|
| 1210 | +{ |
---|
| 1211 | + Elf_Data *data = sec->data; |
---|
| 1212 | + |
---|
| 1213 | + if (data->d_type != ELF_T_BYTE || data->d_off) { |
---|
| 1214 | + WARN("write to unexpected data for section: %s", sec->name); |
---|
| 1215 | + return -1; |
---|
| 1216 | + } |
---|
| 1217 | + |
---|
| 1218 | + memcpy(data->d_buf + offset, insn, len); |
---|
| 1219 | + elf_flagdata(data, ELF_C_SET, ELF_F_DIRTY); |
---|
| 1220 | + |
---|
| 1221 | + elf->changed = true; |
---|
| 1222 | + |
---|
| 1223 | + return 0; |
---|
| 1224 | +} |
---|
| 1225 | + |
---|
| 1226 | +int elf_write_reloc(struct elf *elf, struct reloc *reloc) |
---|
| 1227 | +{ |
---|
| 1228 | + struct section *sec = reloc->sec; |
---|
| 1229 | + |
---|
| 1230 | + if (sec->sh.sh_type == SHT_REL) { |
---|
| 1231 | + reloc->rel.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type); |
---|
| 1232 | + reloc->rel.r_offset = reloc->offset; |
---|
| 1233 | + |
---|
| 1234 | + if (!gelf_update_rel(sec->data, reloc->idx, &reloc->rel)) { |
---|
| 1235 | + WARN_ELF("gelf_update_rel"); |
---|
| 1236 | + return -1; |
---|
| 1237 | + } |
---|
| 1238 | + } else { |
---|
| 1239 | + reloc->rela.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type); |
---|
| 1240 | + reloc->rela.r_addend = reloc->addend; |
---|
| 1241 | + reloc->rela.r_offset = reloc->offset; |
---|
| 1242 | + |
---|
| 1243 | + if (!gelf_update_rela(sec->data, reloc->idx, &reloc->rela)) { |
---|
| 1244 | + WARN_ELF("gelf_update_rela"); |
---|
| 1245 | + return -1; |
---|
| 1246 | + } |
---|
| 1247 | + } |
---|
| 1248 | + |
---|
| 1249 | + elf->changed = true; |
---|
629 | 1250 | |
---|
630 | 1251 | return 0; |
---|
631 | 1252 | } |
---|
.. | .. |
---|
635 | 1256 | struct section *sec; |
---|
636 | 1257 | Elf_Scn *s; |
---|
637 | 1258 | |
---|
638 | | - /* Update section headers for changed sections: */ |
---|
| 1259 | + /* Update changed relocation sections and section headers: */ |
---|
639 | 1260 | list_for_each_entry(sec, &elf->sections, list) { |
---|
640 | 1261 | if (sec->changed) { |
---|
| 1262 | + if (sec->base && |
---|
| 1263 | + elf_rebuild_reloc_section(elf, sec)) { |
---|
| 1264 | + WARN("elf_rebuild_reloc_section"); |
---|
| 1265 | + return -1; |
---|
| 1266 | + } |
---|
| 1267 | + |
---|
641 | 1268 | s = elf_getscn(elf->elf, sec->idx); |
---|
642 | 1269 | if (!s) { |
---|
643 | 1270 | WARN_ELF("elf_getscn"); |
---|
.. | .. |
---|
647 | 1274 | WARN_ELF("gelf_update_shdr"); |
---|
648 | 1275 | return -1; |
---|
649 | 1276 | } |
---|
| 1277 | + |
---|
| 1278 | + sec->changed = false; |
---|
| 1279 | + elf->changed = true; |
---|
650 | 1280 | } |
---|
651 | 1281 | } |
---|
652 | 1282 | |
---|
.. | .. |
---|
659 | 1289 | return -1; |
---|
660 | 1290 | } |
---|
661 | 1291 | |
---|
| 1292 | + elf->changed = false; |
---|
| 1293 | + |
---|
662 | 1294 | return 0; |
---|
663 | 1295 | } |
---|
664 | 1296 | |
---|
.. | .. |
---|
666 | 1298 | { |
---|
667 | 1299 | struct section *sec, *tmpsec; |
---|
668 | 1300 | struct symbol *sym, *tmpsym; |
---|
669 | | - struct rela *rela, *tmprela; |
---|
| 1301 | + struct reloc *reloc, *tmpreloc; |
---|
670 | 1302 | |
---|
671 | 1303 | if (elf->elf) |
---|
672 | 1304 | elf_end(elf->elf); |
---|
.. | .. |
---|
680 | 1312 | hash_del(&sym->hash); |
---|
681 | 1313 | free(sym); |
---|
682 | 1314 | } |
---|
683 | | - list_for_each_entry_safe(rela, tmprela, &sec->rela_list, list) { |
---|
684 | | - list_del(&rela->list); |
---|
685 | | - hash_del(&rela->hash); |
---|
686 | | - free(rela); |
---|
| 1315 | + list_for_each_entry_safe(reloc, tmpreloc, &sec->reloc_list, list) { |
---|
| 1316 | + list_del(&reloc->list); |
---|
| 1317 | + hash_del(&reloc->hash); |
---|
| 1318 | + free(reloc); |
---|
687 | 1319 | } |
---|
688 | 1320 | list_del(&sec->list); |
---|
689 | 1321 | free(sec); |
---|