1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2020 The FreeBSD Foundation
5 *
6 * This software was developed by Tiger Gao under sponsorship from
7 * the FreeBSD Foundation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions are
11 * met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in
16 *    the documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <gelf.h>
32#include <libelf.h>
33
34#include "_libelf.h"
35
36void *
37_libelf_getchdr(Elf_Scn *s, int ec)
38{
39	Elf *e;
40	void *sh;
41	Elf32_Shdr *sh32;
42	Elf64_Shdr *sh64;
43
44	sh32 = NULL;
45	sh64 = NULL;
46
47	if (s == NULL || (e = s->s_elf) == NULL || e->e_kind != ELF_K_ELF) {
48		LIBELF_SET_ERROR(ARGUMENT, 0);
49		return (NULL);
50	}
51
52	if (ec == ELFCLASSNONE) {
53		ec = e->e_class;
54	} else if (ec != e->e_class) {
55		LIBELF_SET_ERROR(CLASS, 0);
56		return (NULL);
57	}
58
59	if ((sh = _libelf_getshdr(s, ec)) == NULL) {
60		LIBELF_SET_ERROR(HEADER, 0);
61		return (NULL);
62	}
63
64	if (ec == ELFCLASS32) {
65		sh32 = (Elf32_Shdr *)sh;
66		if ((sh32->sh_flags & SHF_ALLOC) != 0) {
67			LIBELF_SET_ERROR(INVALID_SECTION_FLAGS, 0);
68			return (NULL);
69		}
70
71		if (sh32->sh_type == SHT_NULL || sh32->sh_type == SHT_NOBITS) {
72			LIBELF_SET_ERROR(INVALID_SECTION_TYPE, 0);
73			return (NULL);
74		}
75
76		if ((sh32->sh_flags & SHF_COMPRESSED) == 0) {
77			LIBELF_SET_ERROR(NOT_COMPRESSED, 0);
78			return (NULL);
79		}
80	} else {
81		sh64 = (Elf64_Shdr *)sh;
82		if ((sh64->sh_flags & SHF_ALLOC) != 0) {
83			LIBELF_SET_ERROR(INVALID_SECTION_FLAGS, 0);
84			return (NULL);
85		}
86
87		if (sh64->sh_type == SHT_NULL || sh64->sh_type == SHT_NOBITS) {
88			LIBELF_SET_ERROR(INVALID_SECTION_TYPE, 0);
89			return (NULL);
90		}
91
92		if ((sh64->sh_flags & SHF_COMPRESSED) == 0) {
93			LIBELF_SET_ERROR(NOT_COMPRESSED, 0);
94			return (NULL);
95		}
96	}
97
98	Elf_Data *d = elf_getdata(s, NULL);
99
100	if (!d)
101		return (NULL);
102
103	return ((void *)d->d_buf);
104}
105