1/* Return string pointer from string section. 2 Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2008, 2009 Red Hat, Inc. 3 This file is part of elfutils. 4 Contributed by Ulrich Drepper <drepper@redhat.com>, 1998. 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 <libelf.h> 35#include <stddef.h> 36 37#include "libelfP.h" 38 39 40char * 41elf_strptr (elf, idx, offset) 42 Elf *elf; 43 size_t idx; 44 size_t offset; 45{ 46 if (elf == NULL) 47 return NULL; 48 49 if (elf->kind != ELF_K_ELF) 50 { 51 __libelf_seterrno (ELF_E_INVALID_HANDLE); 52 return NULL; 53 } 54 55 rwlock_rdlock (elf->lock); 56 57 char *result = NULL; 58 Elf_Scn *strscn; 59 60 /* Find the section in the list. */ 61 Elf_ScnList *runp = (elf->class == ELFCLASS32 62 || (offsetof (struct Elf, state.elf32.scns) 63 == offsetof (struct Elf, state.elf64.scns)) 64 ? &elf->state.elf32.scns : &elf->state.elf64.scns); 65 while (1) 66 { 67 if (idx < runp->max) 68 { 69 if (idx < runp->cnt) 70 strscn = &runp->data[idx]; 71 else 72 { 73 __libelf_seterrno (ELF_E_INVALID_INDEX); 74 goto out; 75 } 76 break; 77 } 78 79 idx -= runp->max; 80 81 runp = runp->next; 82 if (runp == NULL) 83 { 84 __libelf_seterrno (ELF_E_INVALID_INDEX); 85 goto out; 86 } 87 } 88 89 if (elf->class == ELFCLASS32) 90 { 91 if (unlikely (strscn->shdr.e32->sh_type != SHT_STRTAB)) 92 { 93 /* This is no string section. */ 94 __libelf_seterrno (ELF_E_INVALID_SECTION); 95 goto out; 96 } 97 98 if (unlikely (offset >= strscn->shdr.e32->sh_size)) 99 { 100 /* The given offset is too big, it is beyond this section. */ 101 __libelf_seterrno (ELF_E_OFFSET_RANGE); 102 goto out; 103 } 104 } 105 else 106 { 107 if (unlikely (strscn->shdr.e64->sh_type != SHT_STRTAB)) 108 { 109 /* This is no string section. */ 110 __libelf_seterrno (ELF_E_INVALID_SECTION); 111 goto out; 112 } 113 114 if (unlikely (offset >= strscn->shdr.e64->sh_size)) 115 { 116 /* The given offset is too big, it is beyond this section. */ 117 __libelf_seterrno (ELF_E_OFFSET_RANGE); 118 goto out; 119 } 120 } 121 122 if (strscn->rawdata_base == NULL && ! strscn->data_read) 123 { 124 rwlock_unlock (elf->lock); 125 rwlock_wrlock (elf->lock); 126 if (strscn->rawdata_base == NULL && ! strscn->data_read 127 /* Read the section data. */ 128 && __libelf_set_rawdata_wrlock (strscn) != 0) 129 goto out; 130 } 131 132 if (likely (strscn->rawdata_base != NULL)) 133 // XXX Is this correct if a file is read and then new data is added 134 // XXX to the string section? Likely needs to check offset against 135 // XXX size of rawdata_base buffer and then iterate over rest of the 136 // XXX list. 137 result = &strscn->rawdata_base[offset]; 138 else 139 { 140 /* This is a file which is currently created. Use the list of 141 data blocks. */ 142 struct Elf_Data_List *dl = &strscn->data_list; 143 while (dl != NULL) 144 { 145 if (offset >= (size_t) dl->data.d.d_off 146 && offset < dl->data.d.d_off + dl->data.d.d_size) 147 { 148 result = (char *) dl->data.d.d_buf + (offset - dl->data.d.d_off); 149 break; 150 } 151 152 dl = dl->next; 153 } 154 } 155 156 out: 157 rwlock_unlock (elf->lock); 158 159 return result; 160} 161INTDEF(elf_strptr) 162