1/*-
2 * Copyright (c) 2006,2008 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <assert.h>
28#include <gelf.h>
29#include <limits.h>
30#include <stdint.h>
31
32#include "_libelf.h"
33
34ELFTC_VCSID("$Id: gelf_dyn.c 3732 2019-04-22 11:08:38Z jkoshy $");
35
36GElf_Dyn *
37gelf_getdyn(Elf_Data *ed, int ndx, GElf_Dyn *dst)
38{
39	int ec;
40	Elf *e;
41	size_t msz;
42	Elf_Scn *scn;
43	Elf32_Dyn *dyn32;
44	Elf64_Dyn *dyn64;
45	uint32_t sh_type;
46	struct _Libelf_Data *d;
47
48	d = (struct _Libelf_Data *) ed;
49
50	if (d == NULL || ndx < 0 || dst == NULL ||
51	    (scn = d->d_scn) == NULL ||
52	    (e = scn->s_elf) == NULL) {
53		LIBELF_SET_ERROR(ARGUMENT, 0);
54		return (NULL);
55	}
56
57	ec = e->e_class;
58	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
59
60	if (ec == ELFCLASS32)
61		sh_type = scn->s_shdr.s_shdr32.sh_type;
62	else
63		sh_type = scn->s_shdr.s_shdr64.sh_type;
64
65	if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
66		LIBELF_SET_ERROR(ARGUMENT, 0);
67		return (NULL);
68	}
69
70	if ((msz = _libelf_msize(ELF_T_DYN, ec, e->e_version)) == 0)
71		return (NULL);
72
73	assert(ndx >= 0);
74
75	if (msz * (size_t) ndx >= d->d_data.d_size) {
76		LIBELF_SET_ERROR(ARGUMENT, 0);
77		return (NULL);
78	}
79
80	if (ec == ELFCLASS32) {
81		dyn32 = (Elf32_Dyn *) d->d_data.d_buf + ndx;
82
83		dst->d_tag      = dyn32->d_tag;
84		dst->d_un.d_val = (Elf64_Xword) dyn32->d_un.d_val;
85
86	} else {
87
88		dyn64 = (Elf64_Dyn *) d->d_data.d_buf + ndx;
89
90		*dst = *dyn64;
91	}
92
93	return (dst);
94}
95
96int
97gelf_update_dyn(Elf_Data *ed, int ndx, GElf_Dyn *ds)
98{
99	int ec;
100	Elf *e;
101	size_t msz;
102	Elf_Scn *scn;
103	Elf32_Dyn *dyn32;
104	Elf64_Dyn *dyn64;
105	uint32_t sh_type;
106	struct _Libelf_Data *d;
107
108	d = (struct _Libelf_Data *) ed;
109
110	if (d == NULL || ndx < 0 || ds == NULL ||
111	    (scn = d->d_scn) == NULL ||
112	    (e = scn->s_elf) == NULL) {
113		LIBELF_SET_ERROR(ARGUMENT, 0);
114		return (0);
115	}
116
117	ec = e->e_class;
118	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
119
120	if (ec == ELFCLASS32)
121		sh_type = scn->s_shdr.s_shdr32.sh_type;
122	else
123		sh_type = scn->s_shdr.s_shdr64.sh_type;
124
125	if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
126		LIBELF_SET_ERROR(ARGUMENT, 0);
127		return (0);
128	}
129
130	if ((msz = _libelf_msize(ELF_T_DYN, ec, e->e_version)) == 0)
131		return (0);
132
133	assert(ndx >= 0);
134
135	if (msz * (size_t) ndx >= d->d_data.d_size) {
136		LIBELF_SET_ERROR(ARGUMENT, 0);
137		return (0);
138	}
139
140	if (ec == ELFCLASS32) {
141		dyn32 = (Elf32_Dyn *) d->d_data.d_buf + ndx;
142
143		LIBELF_COPY_S32(dyn32, ds, d_tag);
144		LIBELF_COPY_U32(dyn32, ds, d_un.d_val);
145	} else {
146		dyn64 = (Elf64_Dyn *) d->d_data.d_buf + ndx;
147
148		*dyn64 = *ds;
149	}
150
151	return (1);
152}
153