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300 lines
8.2 KiB
300 lines
8.2 KiB
/* Return section header.
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Copyright (C) 1998-2002, 2005, 2007, 2009, 2012, 2014, 2015 Red Hat, Inc.
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This file is part of elfutils.
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Written by Ulrich Drepper <drepper@redhat.com>, 1998.
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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 <errno.h>
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#include <stdbool.h>
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#include <unistd.h>
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#include <system.h>
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#include "libelfP.h"
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#include "common.h"
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#ifndef LIBELFBITS
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# define LIBELFBITS 32
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#endif
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static ElfW2(LIBELFBITS,Shdr) *
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load_shdr_wrlock (Elf_Scn *scn)
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{
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ElfW2(LIBELFBITS,Shdr) *result;
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/* Read the section header table. */
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Elf *elf = scn->elf;
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ElfW2(LIBELFBITS,Ehdr) *ehdr = elf->state.ELFW(elf,LIBELFBITS).ehdr;
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/* Try again, maybe the data is there now. */
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result = scn->shdr.ELFW(e,LIBELFBITS);
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if (result != NULL)
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goto out;
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size_t shnum;
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if (__elf_getshdrnum_rdlock (elf, &shnum) != 0
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|| shnum > SIZE_MAX / sizeof (ElfW2(LIBELFBITS,Shdr)))
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goto out;
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size_t size = shnum * sizeof (ElfW2(LIBELFBITS,Shdr));
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/* Allocate memory for the section headers. We know the number
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of entries from the ELF header. */
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ElfW2(LIBELFBITS,Shdr) *shdr = elf->state.ELFW(elf,LIBELFBITS).shdr =
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(ElfW2(LIBELFBITS,Shdr) *) malloc (size);
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if (elf->state.ELFW(elf,LIBELFBITS).shdr == NULL)
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{
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__libelf_seterrno (ELF_E_NOMEM);
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goto out;
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}
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elf->state.ELFW(elf,LIBELFBITS).shdr_malloced = 1;
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if (elf->map_address != NULL)
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{
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/* First see whether the information in the ELF header is
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valid and it does not ask for too much. */
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if (unlikely (ehdr->e_shoff >= elf->maximum_size)
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|| unlikely (elf->maximum_size - ehdr->e_shoff < size))
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{
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/* Something is wrong. */
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__libelf_seterrno (ELF_E_INVALID_SECTION_HEADER);
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goto free_and_out;
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}
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ElfW2(LIBELFBITS,Shdr) *notcvt;
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/* All the data is already mapped. If we could use it
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directly this would already have happened. Unless
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we allocated the memory ourselves and the ELF_F_MALLOCED
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flag is set. */
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void *file_shdr = ((char *) elf->map_address
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+ elf->start_offset + ehdr->e_shoff);
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assert ((elf->flags & ELF_F_MALLOCED)
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|| ehdr->e_ident[EI_DATA] != MY_ELFDATA
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|| elf->cmd == ELF_C_READ_MMAP
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|| (! ALLOW_UNALIGNED
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&& ((uintptr_t) file_shdr
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& (__alignof__ (ElfW2(LIBELFBITS,Shdr)) - 1)) != 0));
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/* Now copy the data and at the same time convert the byte order. */
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if (ehdr->e_ident[EI_DATA] == MY_ELFDATA)
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{
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assert ((elf->flags & ELF_F_MALLOCED)
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|| elf->cmd == ELF_C_READ_MMAP
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|| ! ALLOW_UNALIGNED);
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memcpy (shdr, file_shdr, size);
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}
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else
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{
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bool copy = ! (ALLOW_UNALIGNED
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|| ((uintptr_t) file_shdr
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& (__alignof__ (ElfW2(LIBELFBITS,Shdr)) - 1))
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== 0);
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if (! copy)
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notcvt = (ElfW2(LIBELFBITS,Shdr) *)
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((char *) elf->map_address
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+ elf->start_offset + ehdr->e_shoff);
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else
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{
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notcvt = (ElfW2(LIBELFBITS,Shdr) *) malloc (size);
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if (unlikely (notcvt == NULL))
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{
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__libelf_seterrno (ELF_E_NOMEM);
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goto out;
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}
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memcpy (notcvt, ((char *) elf->map_address
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+ elf->start_offset + ehdr->e_shoff),
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size);
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}
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for (size_t cnt = 0; cnt < shnum; ++cnt)
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{
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CONVERT_TO (shdr[cnt].sh_name, notcvt[cnt].sh_name);
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CONVERT_TO (shdr[cnt].sh_type, notcvt[cnt].sh_type);
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CONVERT_TO (shdr[cnt].sh_flags, notcvt[cnt].sh_flags);
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CONVERT_TO (shdr[cnt].sh_addr, notcvt[cnt].sh_addr);
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CONVERT_TO (shdr[cnt].sh_offset, notcvt[cnt].sh_offset);
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CONVERT_TO (shdr[cnt].sh_size, notcvt[cnt].sh_size);
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CONVERT_TO (shdr[cnt].sh_link, notcvt[cnt].sh_link);
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CONVERT_TO (shdr[cnt].sh_info, notcvt[cnt].sh_info);
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CONVERT_TO (shdr[cnt].sh_addralign,
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notcvt[cnt].sh_addralign);
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CONVERT_TO (shdr[cnt].sh_entsize, notcvt[cnt].sh_entsize);
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/* If this is a section with an extended index add a
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reference in the section which uses the extended
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index. */
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if (shdr[cnt].sh_type == SHT_SYMTAB_SHNDX
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&& shdr[cnt].sh_link < shnum)
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elf->state.ELFW(elf,LIBELFBITS).scns.data[shdr[cnt].sh_link].shndx_index
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= cnt;
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/* Set the own shndx_index field in case it has not yet
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been set. */
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if (elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shndx_index == 0)
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elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shndx_index
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= -1;
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}
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if (copy)
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free (notcvt);
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}
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}
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else if (likely (elf->fildes != -1))
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{
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/* Read the header. */
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ssize_t n = pread_retry (elf->fildes,
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elf->state.ELFW(elf,LIBELFBITS).shdr, size,
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elf->start_offset + ehdr->e_shoff);
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if (unlikely ((size_t) n != size))
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{
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/* Severe problems. We cannot read the data. */
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__libelf_seterrno (ELF_E_READ_ERROR);
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goto free_and_out;
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}
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/* If the byte order of the file is not the same as the one
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of the host convert the data now. */
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if (ehdr->e_ident[EI_DATA] != MY_ELFDATA)
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for (size_t cnt = 0; cnt < shnum; ++cnt)
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{
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CONVERT (shdr[cnt].sh_name);
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CONVERT (shdr[cnt].sh_type);
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CONVERT (shdr[cnt].sh_flags);
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CONVERT (shdr[cnt].sh_addr);
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CONVERT (shdr[cnt].sh_offset);
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CONVERT (shdr[cnt].sh_size);
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CONVERT (shdr[cnt].sh_link);
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CONVERT (shdr[cnt].sh_info);
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CONVERT (shdr[cnt].sh_addralign);
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CONVERT (shdr[cnt].sh_entsize);
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}
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}
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else
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{
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/* The file descriptor was already enabled and not all data was
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read. Undo the allocation. */
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__libelf_seterrno (ELF_E_FD_DISABLED);
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free_and_out:
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free (shdr);
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elf->state.ELFW(elf,LIBELFBITS).shdr = NULL;
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elf->state.ELFW(elf,LIBELFBITS).shdr_malloced = 0;
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goto out;
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}
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/* Set the pointers in the `scn's. */
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for (size_t cnt = 0; cnt < shnum; ++cnt)
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elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shdr.ELFW(e,LIBELFBITS)
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= &elf->state.ELFW(elf,LIBELFBITS).shdr[cnt];
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result = scn->shdr.ELFW(e,LIBELFBITS);
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assert (result != NULL);
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out:
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return result;
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}
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static bool
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scn_valid (Elf_Scn *scn)
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{
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if (scn == NULL)
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return false;
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if (unlikely (scn->elf->state.elf.ehdr == NULL))
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{
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__libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
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return false;
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}
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if (unlikely (scn->elf->class != ELFW(ELFCLASS,LIBELFBITS)))
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{
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__libelf_seterrno (ELF_E_INVALID_CLASS);
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return false;
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}
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return true;
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}
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ElfW2(LIBELFBITS,Shdr) *
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internal_function
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__elfw2(LIBELFBITS,getshdr_rdlock) (Elf_Scn *scn)
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{
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ElfW2(LIBELFBITS,Shdr) *result;
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if (!scn_valid (scn))
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return NULL;
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result = scn->shdr.ELFW(e,LIBELFBITS);
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if (result == NULL)
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{
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rwlock_unlock (scn->elf->lock);
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rwlock_wrlock (scn->elf->lock);
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result = scn->shdr.ELFW(e,LIBELFBITS);
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if (result == NULL)
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result = load_shdr_wrlock (scn);
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}
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return result;
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}
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ElfW2(LIBELFBITS,Shdr) *
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internal_function
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__elfw2(LIBELFBITS,getshdr_wrlock) (Elf_Scn *scn)
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{
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ElfW2(LIBELFBITS,Shdr) *result;
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if (!scn_valid (scn))
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return NULL;
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result = scn->shdr.ELFW(e,LIBELFBITS);
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if (result == NULL)
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result = load_shdr_wrlock (scn);
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return result;
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}
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ElfW2(LIBELFBITS,Shdr) *
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elfw2(LIBELFBITS,getshdr) (Elf_Scn *scn)
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{
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ElfW2(LIBELFBITS,Shdr) *result;
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if (!scn_valid (scn))
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return NULL;
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rwlock_rdlock (scn->elf->lock);
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result = __elfw2(LIBELFBITS,getshdr_rdlock) (scn);
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rwlock_unlock (scn->elf->lock);
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return result;
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}
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