1 /* Get section at specific index. 2 Copyright (C) 2005, 2008 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 Contributed by Ulrich Drepper <drepper@redhat.com>, 2005. 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 <stddef.h> 57 #include <stdlib.h> 58 59 #include "libelfP.h" 60 61 #ifndef LIBELFBITS 62 # define LIBELFBITS 32 63 #endif 64 65 66 Elf_Scn * 67 elfw2(LIBELFBITS,offscn) (elf, offset) 68 Elf *elf; 69 ElfW2(LIBELFBITS,Off) offset; 70 { 71 if (elf == NULL) 72 return NULL; 73 74 if (unlikely (elf->kind != ELF_K_ELF)) 75 { 76 __libelf_seterrno (ELF_E_INVALID_HANDLE); 77 return NULL; 78 } 79 80 Elf_ScnList *runp = &elf->state.ELFW(elf,LIBELFBITS).scns; 81 82 /* If we have not looked at section headers before, 83 we might need to read them in first. */ 84 if (runp->cnt > 0 85 && unlikely (runp->data[0].shdr.ELFW(e,LIBELFBITS) == NULL) 86 && unlikely (elfw2(LIBELFBITS,getshdr) (&runp->data[0]) == NULL)) 87 return NULL; 88 89 rwlock_rdlock (elf->lock); 90 91 Elf_Scn *result = NULL; 92 93 /* Find the section in the list. */ 94 while (1) 95 { 96 for (unsigned int i = 0; i < runp->cnt; ++i) 97 if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_offset == offset) 98 { 99 result = &runp->data[i]; 100 101 /* If this section is empty, the following one has the same 102 sh_offset. We presume the caller is looking for a nonempty 103 section, so keep looking if this one is empty. */ 104 if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_size != 0) 105 goto out; 106 } 107 108 runp = runp->next; 109 if (runp == NULL) 110 { 111 __libelf_seterrno (ELF_E_INVALID_OFFSET); 112 break; 113 } 114 } 115 116 out: 117 rwlock_unlock (elf->lock); 118 119 return result; 120 } 121 INTDEF(elfw2(LIBELFBITS,offscn)) 122