1 /* Return section index of section header string table. 2 Copyright (C) 2002, 2005 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 Written by Ulrich Drepper <drepper (at) redhat.com>, 2002. 5 6 Red Hat elfutils is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by the 8 Free Software Foundation; version 2 of the License. 9 10 Red Hat elfutils is distributed in the hope that it will be useful, but 11 WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 General Public License for more details. 14 15 You should have received a copy of the GNU General Public License along 16 with Red Hat elfutils; if not, write to the Free Software Foundation, 17 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 18 19 In addition, as a special exception, Red Hat, Inc. gives You the 20 additional right to link the code of Red Hat elfutils with code licensed 21 under any Open Source Initiative certified open source license 22 (http://www.opensource.org/licenses/index.php) which requires the 23 distribution of source code with any binary distribution and to 24 distribute linked combinations of the two. Non-GPL Code permitted under 25 this exception must only link to the code of Red Hat elfutils through 26 those well defined interfaces identified in the file named EXCEPTION 27 found in the source code files (the "Approved Interfaces"). The files 28 of Non-GPL Code may instantiate templates or use macros or inline 29 functions from the Approved Interfaces without causing the resulting 30 work to be covered by the GNU General Public License. Only Red Hat, 31 Inc. may make changes or additions to the list of Approved Interfaces. 32 Red Hat's grant of this exception is conditioned upon your not adding 33 any new exceptions. If you wish to add a new Approved Interface or 34 exception, please contact Red Hat. You must obey the GNU General Public 35 License in all respects for all of the Red Hat elfutils code and other 36 code used in conjunction with Red Hat elfutils except the Non-GPL Code 37 covered by this exception. If you modify this file, you may extend this 38 exception to your version of the file, but you are not obligated to do 39 so. If you do not wish to provide this exception without modification, 40 you must delete this exception statement from your version and license 41 this file solely under the GPL without exception. 42 43 Red Hat elfutils is an included package of the Open Invention Network. 44 An included package of the Open Invention Network is a package for which 45 Open Invention Network licensees cross-license their patents. No patent 46 license is granted, either expressly or impliedly, by designation as an 47 included package. Should you wish to participate in the Open Invention 48 Network licensing program, please visit www.openinventionnetwork.com 49 <http://www.openinventionnetwork.com>. */ 50 51 #ifdef HAVE_CONFIG_H 52 # include <config.h> 53 #endif 54 55 #include <assert.h> 56 #include <errno.h> 57 #include <gelf.h> 58 #include <stddef.h> 59 #include <unistd.h> 60 61 #include <system.h> 62 #include "libelfP.h" 63 #include "common.h" 64 65 66 int 67 elf_getshstrndx (elf, dst) 68 Elf *elf; 69 size_t *dst; 70 { 71 int result = 0; 72 73 if (elf == NULL) 74 return -1; 75 76 if (unlikely (elf->kind != ELF_K_ELF)) 77 { 78 __libelf_seterrno (ELF_E_INVALID_HANDLE); 79 return -1; 80 } 81 82 rwlock_rdlock (elf->lock); 83 84 /* We rely here on the fact that the `elf' element is a common prefix 85 of `elf32' and `elf64'. */ 86 assert (offsetof (struct Elf, state.elf.ehdr) 87 == offsetof (struct Elf, state.elf32.ehdr)); 88 assert (sizeof (elf->state.elf.ehdr) 89 == sizeof (elf->state.elf32.ehdr)); 90 assert (offsetof (struct Elf, state.elf.ehdr) 91 == offsetof (struct Elf, state.elf64.ehdr)); 92 assert (sizeof (elf->state.elf.ehdr) 93 == sizeof (elf->state.elf64.ehdr)); 94 95 if (unlikely (elf->state.elf.ehdr == NULL)) 96 { 97 __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR); 98 result = -1; 99 } 100 else 101 { 102 Elf32_Word num; 103 104 num = (elf->class == ELFCLASS32 105 ? elf->state.elf32.ehdr->e_shstrndx 106 : elf->state.elf64.ehdr->e_shstrndx); 107 108 /* Determine whether the index is too big to fit in the ELF 109 header. */ 110 if (unlikely (num == SHN_XINDEX)) 111 { 112 /* Yes. Search the zeroth section header. */ 113 if (elf->class == ELFCLASS32) 114 { 115 size_t offset; 116 117 if (elf->state.elf32.scns.data[0].shdr.e32 != NULL) 118 { 119 num = elf->state.elf32.scns.data[0].shdr.e32->sh_link; 120 goto success; 121 } 122 123 offset = elf->state.elf32.ehdr->e_shoff; 124 125 if (elf->map_address != NULL 126 && elf->state.elf32.ehdr->e_ident[EI_DATA] == MY_ELFDATA 127 && (ALLOW_UNALIGNED 128 || (((size_t) ((char *) elf->map_address + offset)) 129 & (__alignof__ (Elf32_Shdr) - 1)) == 0)) 130 /* We can directly access the memory. */ 131 num = ((Elf32_Shdr *) (elf->map_address + offset))->sh_link; 132 else 133 { 134 /* We avoid reading in all the section headers. Just read 135 the first one. */ 136 Elf32_Shdr shdr_mem; 137 138 if (unlikely (pread_retry (elf->fildes, &shdr_mem, 139 sizeof (Elf32_Shdr), offset) 140 != sizeof (Elf32_Shdr))) 141 { 142 /* We must be able to read this ELF section header. */ 143 __libelf_seterrno (ELF_E_INVALID_FILE); 144 result = -1; 145 goto out; 146 } 147 148 if (elf->state.elf32.ehdr->e_ident[EI_DATA] != MY_ELFDATA) 149 CONVERT (shdr_mem.sh_link); 150 num = shdr_mem.sh_link; 151 } 152 } 153 else 154 { 155 if (elf->state.elf64.scns.data[0].shdr.e64 != NULL) 156 { 157 num = elf->state.elf64.scns.data[0].shdr.e64->sh_link; 158 goto success; 159 } 160 161 size_t offset = elf->state.elf64.ehdr->e_shoff; 162 163 if (elf->map_address != NULL 164 && elf->state.elf64.ehdr->e_ident[EI_DATA] == MY_ELFDATA 165 && (ALLOW_UNALIGNED 166 || (((size_t) ((char *) elf->map_address + offset)) 167 & (__alignof__ (Elf64_Shdr) - 1)) == 0)) 168 /* We can directly access the memory. */ 169 num = ((Elf64_Shdr *) (elf->map_address + offset))->sh_link; 170 else 171 { 172 /* We avoid reading in all the section headers. Just read 173 the first one. */ 174 Elf64_Shdr shdr_mem; 175 176 if (unlikely (pread_retry (elf->fildes, &shdr_mem, 177 sizeof (Elf64_Shdr), offset) 178 != sizeof (Elf64_Shdr))) 179 { 180 /* We must be able to read this ELF section header. */ 181 __libelf_seterrno (ELF_E_INVALID_FILE); 182 result = -1; 183 goto out; 184 } 185 186 if (elf->state.elf64.ehdr->e_ident[EI_DATA] != MY_ELFDATA) 187 CONVERT (shdr_mem.sh_link); 188 num = shdr_mem.sh_link; 189 } 190 } 191 } 192 193 /* Store the result. */ 194 success: 195 *dst = num; 196 } 197 198 out: 199 rwlock_unlock (elf->lock); 200 201 return result; 202 } 203 INTDEF(elf_getshstrndx) 204
