1 /* Get ELF header.
2 Copyright (C) 1998, 1999, 2000, 2002, 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 <libelf.h>
35 #include <stddef.h>
36
37 #include "libelfP.h"
38
39 #ifndef LIBELFBITS
40 # define LIBELFBITS 32
41 #endif
42
43
ElfW2(LIBELFBITS,Ehdr)44 static ElfW2(LIBELFBITS,Ehdr) *
45 getehdr_impl (Elf *elf, int wrlock)
46 {
47 if (elf == NULL)
48 return NULL;
49
50 if (unlikely (elf->kind != ELF_K_ELF))
51 {
52 __libelf_seterrno (ELF_E_INVALID_HANDLE);
53 return NULL;
54 }
55
56 again:
57 if (elf->class == 0)
58 {
59 if (!wrlock)
60 {
61 rwlock_unlock (elf->lock);
62 rwlock_wrlock (elf->lock);
63 wrlock = 1;
64 goto again;
65 }
66 elf->class = ELFW(ELFCLASS,LIBELFBITS);
67 }
68 else if (unlikely (elf->class != ELFW(ELFCLASS,LIBELFBITS)))
69 {
70 __libelf_seterrno (ELF_E_INVALID_CLASS);
71 return NULL;
72 }
73
74 return elf->state.ELFW(elf,LIBELFBITS).ehdr;
75 }
76
ElfW2(LIBELFBITS,Ehdr)77 ElfW2(LIBELFBITS,Ehdr) *
78 internal_function
79 __elfw2(LIBELFBITS,getehdr_wrlock) (Elf *elf)
80 {
81 return getehdr_impl (elf, 1);
82 }
83
ElfW2(LIBELFBITS,Ehdr)84 ElfW2(LIBELFBITS,Ehdr) *
85 elfw2(LIBELFBITS,getehdr) (Elf *elf)
86 {
87 ElfW2(LIBELFBITS,Ehdr) *result;
88 if (elf == NULL)
89 return NULL;
90
91 rwlock_rdlock (elf->lock);
92 result = getehdr_impl (elf, 0);
93 rwlock_unlock (elf->lock);
94
95 return result;
96 }
97