1 /* Get section at specific index. 2 Copyright (C) 2005, 2008, 2015 Red Hat, Inc. 3 This file is part of elfutils. 4 Contributed by Ulrich Drepper <drepper (at) redhat.com>, 2005. 5 6 This file is free software; you can redistribute it and/or modify 7 it under the terms of either 8 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 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 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/>. */ 29 30 #ifdef HAVE_CONFIG_H 31 # include <config.h> 32 #endif 33 34 #include <assert.h> 35 #include <stddef.h> 36 #include <stdlib.h> 37 38 #include "libelfP.h" 39 40 #ifndef LIBELFBITS 41 # define LIBELFBITS 32 42 #endif 43 44 45 Elf_Scn * 46 elfw2(LIBELFBITS,offscn) (Elf *elf, ElfW2(LIBELFBITS,Off) offset) 47 { 48 if (elf == NULL) 49 return NULL; 50 51 if (unlikely (elf->kind != ELF_K_ELF)) 52 { 53 __libelf_seterrno (ELF_E_INVALID_HANDLE); 54 return NULL; 55 } 56 57 Elf_ScnList *runp = &elf->state.ELFW(elf,LIBELFBITS).scns; 58 59 /* If we have not looked at section headers before, 60 we might need to read them in first. */ 61 if (runp->cnt > 0 62 && unlikely (runp->data[0].shdr.ELFW(e,LIBELFBITS) == NULL) 63 && unlikely (elfw2(LIBELFBITS,getshdr) (&runp->data[0]) == NULL)) 64 return NULL; 65 66 rwlock_rdlock (elf->lock); 67 68 Elf_Scn *result = NULL; 69 70 /* Find the section in the list. */ 71 while (1) 72 { 73 for (unsigned int i = 0; i < runp->cnt; ++i) 74 if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_offset == offset) 75 { 76 result = &runp->data[i]; 77 78 /* If this section is empty, the following one has the same 79 sh_offset. We presume the caller is looking for a nonempty 80 section, so keep looking if this one is empty. */ 81 if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_size != 0 82 && runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_type != SHT_NOBITS) 83 goto out; 84 } 85 86 runp = runp->next; 87 if (runp == NULL) 88 { 89 __libelf_seterrno (ELF_E_INVALID_OFFSET); 90 break; 91 } 92 } 93 94 out: 95 rwlock_unlock (elf->lock); 96 97 return result; 98 } 99 INTDEF(elfw2(LIBELFBITS,offscn)) 100
