Ulrich Drepper | b08d5a8 | 2005-07-26 05:00:05 +0000 | [diff] [blame^] | 1 | /* Return section index of section header string table. |
| 2 | Copyright (C) 2002 Red Hat, Inc. |
| 3 | Written by Ulrich Drepper <drepper@redhat.com>, 2002. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation, version 2. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | GNU General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License |
| 15 | along with this program; if not, write to the Free Software Foundation, |
| 16 | Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 17 | |
| 18 | #ifdef HAVE_CONFIG_H |
| 19 | # include <config.h> |
| 20 | #endif |
| 21 | |
| 22 | #include <assert.h> |
| 23 | #include <gelf.h> |
| 24 | #include <stddef.h> |
| 25 | #include <unistd.h> |
| 26 | |
| 27 | #include "libelfP.h" |
| 28 | #include "common.h" |
| 29 | |
| 30 | |
| 31 | int |
| 32 | elf_getshstrndx (elf, dst) |
| 33 | Elf *elf; |
| 34 | size_t *dst; |
| 35 | { |
| 36 | int result = 0; |
| 37 | |
| 38 | if (elf == NULL) |
| 39 | return -1; |
| 40 | |
| 41 | if (unlikely (elf->kind != ELF_K_ELF)) |
| 42 | { |
| 43 | __libelf_seterrno (ELF_E_INVALID_HANDLE); |
| 44 | return -1; |
| 45 | } |
| 46 | |
| 47 | rwlock_rdlock (elf->lock); |
| 48 | |
| 49 | /* We rely here on the fact that the `elf' element is a common prefix |
| 50 | of `elf32' and `elf64'. */ |
| 51 | assert (offsetof (struct Elf, state.elf.ehdr) |
| 52 | == offsetof (struct Elf, state.elf32.ehdr)); |
| 53 | assert (sizeof (elf->state.elf.ehdr) |
| 54 | == sizeof (elf->state.elf32.ehdr)); |
| 55 | assert (offsetof (struct Elf, state.elf.ehdr) |
| 56 | == offsetof (struct Elf, state.elf64.ehdr)); |
| 57 | assert (sizeof (elf->state.elf.ehdr) |
| 58 | == sizeof (elf->state.elf64.ehdr)); |
| 59 | |
| 60 | if (unlikely (elf->state.elf.ehdr == NULL)) |
| 61 | { |
| 62 | __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR); |
| 63 | result = -1; |
| 64 | } |
| 65 | else |
| 66 | { |
| 67 | Elf32_Word num; |
| 68 | |
| 69 | num = (elf->class == ELFCLASS32 |
| 70 | ? elf->state.elf32.ehdr->e_shstrndx |
| 71 | : elf->state.elf64.ehdr->e_shstrndx); |
| 72 | |
| 73 | /* Determine whether the index is too big to fit in the ELF |
| 74 | header. */ |
| 75 | if (unlikely (num == SHN_XINDEX)) |
| 76 | { |
| 77 | /* Yes. Search the zeroth section header. */ |
| 78 | if (elf->class == ELFCLASS32) |
| 79 | { |
| 80 | size_t offset; |
| 81 | |
| 82 | if (elf->state.elf32.scns.data[0].shdr.e32 != NULL) |
| 83 | { |
| 84 | num = elf->state.elf32.scns.data[0].shdr.e32->sh_link; |
| 85 | goto success; |
| 86 | } |
| 87 | |
| 88 | offset = elf->state.elf32.ehdr->e_shoff; |
| 89 | |
| 90 | if (elf->map_address != NULL |
| 91 | && elf->state.elf32.ehdr->e_ident[EI_DATA] == MY_ELFDATA |
| 92 | && (ALLOW_UNALIGNED |
| 93 | || (((size_t) ((char *) elf->map_address + offset)) |
| 94 | & (__alignof__ (Elf32_Shdr) - 1)) == 0)) |
| 95 | /* We can directly access the memory. */ |
| 96 | num = ((Elf32_Shdr *) (elf->map_address + offset))->sh_link; |
| 97 | else |
| 98 | { |
| 99 | /* We avoid reading in all the section headers. Just read |
| 100 | the first one. */ |
| 101 | Elf32_Shdr shdr_mem; |
| 102 | |
| 103 | if (pread (elf->fildes, &shdr_mem, sizeof (Elf32_Shdr), |
| 104 | offset) != sizeof (Elf32_Shdr)) |
| 105 | { |
| 106 | /* We must be able to read this ELF section header. */ |
| 107 | __libelf_seterrno (ELF_E_INVALID_FILE); |
| 108 | result = -1; |
| 109 | goto out; |
| 110 | } |
| 111 | |
| 112 | if (elf->state.elf32.ehdr->e_ident[EI_DATA] != MY_ELFDATA) |
| 113 | CONVERT (shdr_mem.sh_link); |
| 114 | num = shdr_mem.sh_link; |
| 115 | } |
| 116 | } |
| 117 | else |
| 118 | { |
| 119 | size_t offset; |
| 120 | |
| 121 | if (elf->state.elf64.scns.data[0].shdr.e64 != NULL) |
| 122 | { |
| 123 | num = elf->state.elf64.scns.data[0].shdr.e64->sh_link; |
| 124 | goto success; |
| 125 | } |
| 126 | |
| 127 | offset = elf->state.elf64.ehdr->e_shoff; |
| 128 | |
| 129 | if (elf->map_address != NULL |
| 130 | && elf->state.elf64.ehdr->e_ident[EI_DATA] == MY_ELFDATA |
| 131 | && (ALLOW_UNALIGNED |
| 132 | || (((size_t) ((char *) elf->map_address + offset)) |
| 133 | & (__alignof__ (Elf64_Shdr) - 1)) == 0)) |
| 134 | /* We can directly access the memory. */ |
| 135 | num = ((Elf64_Shdr *) (elf->map_address + offset))->sh_link; |
| 136 | else |
| 137 | { |
| 138 | /* We avoid reading in all the section headers. Just read |
| 139 | the first one. */ |
| 140 | Elf64_Shdr shdr_mem; |
| 141 | |
| 142 | if (pread (elf->fildes, &shdr_mem, sizeof (Elf64_Shdr), |
| 143 | offset) != sizeof (Elf64_Shdr)) |
| 144 | { |
| 145 | /* We must be able to read this ELF section header. */ |
| 146 | __libelf_seterrno (ELF_E_INVALID_FILE); |
| 147 | result = -1; |
| 148 | goto out; |
| 149 | } |
| 150 | |
| 151 | if (elf->state.elf64.ehdr->e_ident[EI_DATA] != MY_ELFDATA) |
| 152 | CONVERT (shdr_mem.sh_link); |
| 153 | num = shdr_mem.sh_link; |
| 154 | } |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | /* Store the result. */ |
| 159 | success: |
| 160 | *dst = num; |
| 161 | } |
| 162 | |
| 163 | out: |
| 164 | rwlock_unlock (elf->lock); |
| 165 | |
| 166 | return result; |
| 167 | } |
| 168 | INTDEF(elf_getshstrndx) |