libelf/gelf_getehdr.c

   1 /* Get ELF header.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2005, 2015 Red Hat, Inc.
   3    This file is part of elfutils.
   4    Written 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 <gelf.h>
  35 #include <stddef.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #include "libelfP.h"
  40
  41
  42 GElf_Ehdr *
  43 internal_function
  44 __gelf_getehdr_rdlock (Elf *elf, GElf_Ehdr *dest)
  45 {
  46   GElf_Ehdr *result = NULL;
  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   /* The following is an optimization: the ehdr element is at the same
  58      position in both the elf32 and elf64 structure.  */
  59   if (offsetof (struct Elf, state.elf32.ehdr)
  60       != offsetof (struct Elf, state.elf64.ehdr))
  61     abort ();
  62   /* Just pick one of the values.  */
  63  if (unlikely (elf->state.elf64.ehdr == NULL))
  64     /* Maybe no ELF header was created yet.  */
  65     __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
  66   else if (elf->class == ELFCLASS32)
  67     {
  68       Elf32_Ehdr *ehdr = elf->state.elf32.ehdr;
  69
  70       /* Convert the 32-bit struct to an 64-bit one.  */
  71       memcpy (dest->e_ident, ehdr->e_ident, EI_NIDENT);
  72 #define COPY(name) \
  73       dest->name = ehdr->name
  74       COPY (e_type);
  75       COPY (e_machine);
  76       COPY (e_version);
  77       COPY (e_entry);
  78       COPY (e_phoff);
  79       COPY (e_shoff);
  80       COPY (e_flags);
  81       COPY (e_ehsize);
  82       COPY (e_phentsize);
  83       COPY (e_phnum);
  84       COPY (e_shentsize);
  85       COPY (e_shnum);
  86       COPY (e_shstrndx);
  87
  88       result = dest;
  89     }
  90   else
  91     result = memcpy (dest, elf->state.elf64.ehdr, sizeof (*dest));
  92
  93   return result;
  94 }
  95
  96 GElf_Ehdr *
  97 gelf_getehdr (Elf *elf, GElf_Ehdr *dest)
  98 {
  99   GElf_Ehdr *result;
 100   if (elf == NULL)
 101     return NULL;
 102
 103   rwlock_rdlock (elf->lock);
 104   result = __gelf_getehdr_rdlock (elf, dest);
 105   rwlock_unlock (elf->lock);
 106
 107   return result;
 108 }