Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 1 | /* Return section index of section header string table. |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 2 | Copyright (C) 2002, 2005, 2009, 2014 Red Hat, Inc. |
| 3 | This file is part of elfutils. |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 4 | Written by Ulrich Drepper <drepper@redhat.com>, 2002. |
| 5 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 6 | This file is free software; you can redistribute it and/or modify |
| 7 | it under the terms of either |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 8 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 9 | * the GNU Lesser General Public License as published by the Free |
| 10 | Software Foundation; either version 3 of the License, or (at |
| 11 | your option) any later version |
| 12 | |
| 13 | or |
| 14 | |
| 15 | * the GNU General Public License as published by the Free |
| 16 | Software Foundation; either version 2 of the License, or (at |
| 17 | your option) any later version |
| 18 | |
| 19 | or both in parallel, as here. |
| 20 | |
| 21 | elfutils is distributed in the hope that it will be useful, but |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 22 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 23 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 24 | General Public License for more details. |
| 25 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 26 | You should have received copies of the GNU General Public License and |
| 27 | the GNU Lesser General Public License along with this program. If |
| 28 | not, see <http://www.gnu.org/licenses/>. */ |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 29 | |
| 30 | #ifdef HAVE_CONFIG_H |
| 31 | # include <config.h> |
| 32 | #endif |
| 33 | |
| 34 | #include <assert.h> |
| 35 | #include <errno.h> |
| 36 | #include <gelf.h> |
| 37 | #include <stddef.h> |
| 38 | #include <unistd.h> |
| 39 | |
| 40 | #include <system.h> |
| 41 | #include "libelfP.h" |
| 42 | #include "common.h" |
| 43 | |
| 44 | |
| 45 | int |
| 46 | elf_getshdrstrndx (elf, dst) |
| 47 | Elf *elf; |
| 48 | size_t *dst; |
| 49 | { |
| 50 | int result = 0; |
| 51 | |
| 52 | if (elf == NULL) |
| 53 | return -1; |
| 54 | |
| 55 | if (unlikely (elf->kind != ELF_K_ELF)) |
| 56 | { |
| 57 | __libelf_seterrno (ELF_E_INVALID_HANDLE); |
| 58 | return -1; |
| 59 | } |
| 60 | |
| 61 | rwlock_rdlock (elf->lock); |
| 62 | |
| 63 | /* We rely here on the fact that the `elf' element is a common prefix |
| 64 | of `elf32' and `elf64'. */ |
| 65 | assert (offsetof (struct Elf, state.elf.ehdr) |
| 66 | == offsetof (struct Elf, state.elf32.ehdr)); |
| 67 | assert (sizeof (elf->state.elf.ehdr) |
| 68 | == sizeof (elf->state.elf32.ehdr)); |
| 69 | assert (offsetof (struct Elf, state.elf.ehdr) |
| 70 | == offsetof (struct Elf, state.elf64.ehdr)); |
| 71 | assert (sizeof (elf->state.elf.ehdr) |
| 72 | == sizeof (elf->state.elf64.ehdr)); |
| 73 | |
| 74 | if (unlikely (elf->state.elf.ehdr == NULL)) |
| 75 | { |
| 76 | __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR); |
| 77 | result = -1; |
| 78 | } |
| 79 | else |
| 80 | { |
| 81 | Elf32_Word num; |
| 82 | |
| 83 | num = (elf->class == ELFCLASS32 |
| 84 | ? elf->state.elf32.ehdr->e_shstrndx |
| 85 | : elf->state.elf64.ehdr->e_shstrndx); |
| 86 | |
| 87 | /* Determine whether the index is too big to fit in the ELF |
| 88 | header. */ |
| 89 | if (unlikely (num == SHN_XINDEX)) |
| 90 | { |
| 91 | /* Yes. Search the zeroth section header. */ |
| 92 | if (elf->class == ELFCLASS32) |
| 93 | { |
| 94 | size_t offset; |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 95 | if (unlikely (elf->state.elf32.scns.cnt == 0)) |
| 96 | { |
| 97 | /* Cannot use SHN_XINDEX without section headers. */ |
| 98 | __libelf_seterrno (ELF_E_INVALID_SECTION_HEADER); |
| 99 | result = -1; |
| 100 | goto out; |
| 101 | } |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 102 | |
| 103 | if (elf->state.elf32.scns.data[0].shdr.e32 != NULL) |
| 104 | { |
| 105 | num = elf->state.elf32.scns.data[0].shdr.e32->sh_link; |
| 106 | goto success; |
| 107 | } |
| 108 | |
| 109 | offset = elf->state.elf32.ehdr->e_shoff; |
| 110 | |
| 111 | if (elf->map_address != NULL |
| 112 | && elf->state.elf32.ehdr->e_ident[EI_DATA] == MY_ELFDATA |
| 113 | && (ALLOW_UNALIGNED |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 114 | || (((size_t) ((char *) elf->map_address |
| 115 | + elf->start_offset + offset)) |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 116 | & (__alignof__ (Elf32_Shdr) - 1)) == 0)) |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 117 | { |
| 118 | /* First see whether the information in the ELF header is |
| 119 | valid and it does not ask for too much. */ |
| 120 | if (unlikely (elf->maximum_size - offset |
| 121 | < sizeof (Elf32_Shdr))) |
| 122 | { |
| 123 | /* Something is wrong. */ |
| 124 | __libelf_seterrno (ELF_E_INVALID_SECTION_HEADER); |
| 125 | result = -1; |
| 126 | goto out; |
| 127 | } |
| 128 | |
| 129 | /* We can directly access the memory. */ |
| 130 | num = ((Elf32_Shdr *) (elf->map_address + elf->start_offset |
| 131 | + offset))->sh_link; |
| 132 | } |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 133 | else |
| 134 | { |
| 135 | /* We avoid reading in all the section headers. Just read |
| 136 | the first one. */ |
| 137 | Elf32_Shdr shdr_mem; |
| 138 | |
| 139 | if (unlikely (pread_retry (elf->fildes, &shdr_mem, |
| 140 | sizeof (Elf32_Shdr), offset) |
| 141 | != sizeof (Elf32_Shdr))) |
| 142 | { |
| 143 | /* We must be able to read this ELF section header. */ |
| 144 | __libelf_seterrno (ELF_E_INVALID_FILE); |
| 145 | result = -1; |
| 146 | goto out; |
| 147 | } |
| 148 | |
| 149 | if (elf->state.elf32.ehdr->e_ident[EI_DATA] != MY_ELFDATA) |
| 150 | CONVERT (shdr_mem.sh_link); |
| 151 | num = shdr_mem.sh_link; |
| 152 | } |
| 153 | } |
| 154 | else |
| 155 | { |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 156 | if (unlikely (elf->state.elf64.scns.cnt == 0)) |
| 157 | { |
| 158 | /* Cannot use SHN_XINDEX without section headers. */ |
| 159 | __libelf_seterrno (ELF_E_INVALID_SECTION_HEADER); |
| 160 | result = -1; |
| 161 | goto out; |
| 162 | } |
| 163 | |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 164 | if (elf->state.elf64.scns.data[0].shdr.e64 != NULL) |
| 165 | { |
| 166 | num = elf->state.elf64.scns.data[0].shdr.e64->sh_link; |
| 167 | goto success; |
| 168 | } |
| 169 | |
| 170 | size_t offset = elf->state.elf64.ehdr->e_shoff; |
| 171 | |
| 172 | if (elf->map_address != NULL |
| 173 | && elf->state.elf64.ehdr->e_ident[EI_DATA] == MY_ELFDATA |
| 174 | && (ALLOW_UNALIGNED |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 175 | || (((size_t) ((char *) elf->map_address |
| 176 | + elf->start_offset + offset)) |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 177 | & (__alignof__ (Elf64_Shdr) - 1)) == 0)) |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 178 | { |
| 179 | /* First see whether the information in the ELF header is |
| 180 | valid and it does not ask for too much. */ |
| 181 | if (unlikely (elf->maximum_size - offset |
| 182 | < sizeof (Elf64_Shdr))) |
| 183 | { |
| 184 | /* Something is wrong. */ |
| 185 | __libelf_seterrno (ELF_E_INVALID_SECTION_HEADER); |
| 186 | result = -1; |
| 187 | goto out; |
| 188 | } |
| 189 | |
| 190 | /* We can directly access the memory. */ |
| 191 | num = ((Elf64_Shdr *) (elf->map_address + elf->start_offset |
| 192 | + offset))->sh_link; |
| 193 | } |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 194 | else |
| 195 | { |
| 196 | /* We avoid reading in all the section headers. Just read |
| 197 | the first one. */ |
| 198 | Elf64_Shdr shdr_mem; |
| 199 | |
| 200 | if (unlikely (pread_retry (elf->fildes, &shdr_mem, |
| 201 | sizeof (Elf64_Shdr), offset) |
| 202 | != sizeof (Elf64_Shdr))) |
| 203 | { |
| 204 | /* We must be able to read this ELF section header. */ |
| 205 | __libelf_seterrno (ELF_E_INVALID_FILE); |
| 206 | result = -1; |
| 207 | goto out; |
| 208 | } |
| 209 | |
| 210 | if (elf->state.elf64.ehdr->e_ident[EI_DATA] != MY_ELFDATA) |
| 211 | CONVERT (shdr_mem.sh_link); |
| 212 | num = shdr_mem.sh_link; |
| 213 | } |
| 214 | } |
| 215 | } |
| 216 | |
| 217 | /* Store the result. */ |
| 218 | success: |
| 219 | *dst = num; |
| 220 | } |
| 221 | |
| 222 | out: |
| 223 | rwlock_unlock (elf->lock); |
| 224 | |
| 225 | return result; |
| 226 | } |
| 227 | INTDEF(elf_getshdrstrndx) |
| 228 | /* Alias for the deprecated name. */ |
| 229 | strong_alias (elf_getshdrstrndx, elf_getshstrndx) |