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117 lines
3.2 KiB
117 lines
3.2 KiB
/* Get note information at the supplied offset.
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Copyright (C) 2007, 2014, 2015, 2018 Red Hat, Inc.
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This file is part of elfutils.
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This file is free software; you can redistribute it and/or modify
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it under the terms of either
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at
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your option) any later version
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at
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your option) any later version
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or both in parallel, as here.
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elfutils is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see <http://www.gnu.org/licenses/>. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <assert.h>
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#include <gelf.h>
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#include <string.h>
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#include "libelfP.h"
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size_t
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gelf_getnote (Elf_Data *data, size_t offset, GElf_Nhdr *result,
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size_t *name_offset, size_t *desc_offset)
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{
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if (data == NULL)
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return 0;
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if (unlikely (data->d_type != ELF_T_NHDR && data->d_type != ELF_T_NHDR8))
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{
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__libelf_seterrno (ELF_E_INVALID_HANDLE);
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return 0;
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}
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/* It's easy to handle this type. It has the same size for 32 and
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64 bit objects. */
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assert (sizeof (GElf_Nhdr) == sizeof (Elf32_Nhdr));
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assert (sizeof (GElf_Nhdr) == sizeof (Elf64_Nhdr));
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rwlock_rdlock (((Elf_Data_Scn *) data)->s->elf->lock);
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/* The data is already in the correct form. Just make sure the
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offset is OK. */
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if (unlikely (offset > data->d_size
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|| data->d_size - offset < sizeof (GElf_Nhdr)))
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{
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__libelf_seterrno (ELF_E_OFFSET_RANGE);
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offset = 0;
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}
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else
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{
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const GElf_Nhdr *n = data->d_buf + offset;
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offset += sizeof *n;
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if (offset > data->d_size)
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offset = 0;
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else
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{
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/* This is slightly tricky, offset is guaranteed to be 4
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byte aligned, which is what we need for the name_offset.
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And normally desc_offset is also 4 byte aligned, but not
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for GNU Property notes, then it should be 8. So align
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the offset, after adding the namesz, and include padding
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in descsz to get to the end. */
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*name_offset = offset;
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if (n->n_namesz > data->d_size
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|| offset > data->d_size - n->n_namesz)
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offset = 0;
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else
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{
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offset += n->n_namesz;
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/* Include padding. Check below for overflow. */
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GElf_Word descsz = (data->d_type == ELF_T_NHDR8
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? NOTE_ALIGN8 (n->n_descsz)
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: NOTE_ALIGN4 (n->n_descsz));
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if (data->d_type == ELF_T_NHDR8)
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offset = NOTE_ALIGN8 (offset);
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else
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offset = NOTE_ALIGN4 (offset);
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if (unlikely (offset > data->d_size
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|| data->d_size - offset < descsz
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|| (descsz == 0 && n->n_descsz != 0)))
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offset = 0;
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else
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{
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*desc_offset = offset;
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offset += descsz;
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*result = *n;
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}
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}
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}
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}
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rwlock_unlock (((Elf_Data_Scn *) data)->s->elf->lock);
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return offset;
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}
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