libelf_phdr.c revision 280932 
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 <libelf.h>
30#include <stdlib.h>
31
32#include "_libelf.h"
33
34ELFTC_VCSID("$Id: libelf_phdr.c 3174 2015-03-27 17:13:41Z emaste $");
35
36void *
37_libelf_getphdr(Elf *e, int ec)
38{
39	size_t phnum;
40	size_t fsz, msz;
41	uint64_t phoff;
42	Elf32_Ehdr *eh32;
43	Elf64_Ehdr *eh64;
44	void *ehdr, *phdr;
45	int (*xlator)(unsigned char *_d, size_t _dsz, unsigned char *_s,
46	    size_t _c, int _swap);
47
48	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
49
50	if (e == NULL) {
51		LIBELF_SET_ERROR(ARGUMENT, 0);
52		return (NULL);
53	}
54
55	if ((phdr = (ec == ELFCLASS32 ?
56		 (void *) e->e_u.e_elf.e_phdr.e_phdr32 :
57		 (void *) e->e_u.e_elf.e_phdr.e_phdr64)) != NULL)
58		return (phdr);
59
60	/*
61	 * Check the PHDR related fields in the EHDR for sanity.
62	 */
63
64	if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
65		return (NULL);
66
67	phnum = e->e_u.e_elf.e_nphdr;
68
69	if (ec == ELFCLASS32) {
70		eh32      = (Elf32_Ehdr *) ehdr;
71		phoff     = (uint64_t) eh32->e_phoff;
72	} else {
73		eh64      = (Elf64_Ehdr *) ehdr;
74		phoff     = (uint64_t) eh64->e_phoff;
75	}
76
77	fsz = gelf_fsize(e, ELF_T_PHDR, phnum, e->e_version);
78
79	assert(fsz > 0);
80
81	if ((uint64_t) e->e_rawsize < (phoff + fsz)) {
82		LIBELF_SET_ERROR(HEADER, 0);
83		return (NULL);
84	}
85
86	msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT);
87
88	assert(msz > 0);
89
90	if ((phdr = calloc(phnum, msz)) == NULL) {
91		LIBELF_SET_ERROR(RESOURCE, 0);
92		return (NULL);
93	}
94
95	if (ec == ELFCLASS32)
96		e->e_u.e_elf.e_phdr.e_phdr32 = phdr;
97	else
98		e->e_u.e_elf.e_phdr.e_phdr64 = phdr;
99
100
101	xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec);
102	(*xlator)(phdr, phnum * msz, e->e_rawfile + phoff, phnum,
103	    e->e_byteorder != LIBELF_PRIVATE(byteorder));
104
105	return (phdr);
106}
107
108void *
109_libelf_newphdr(Elf *e, int ec, size_t count)
110{
111	void *ehdr, *newphdr, *oldphdr;
112	size_t msz;
113
114	if (e == NULL) {
115		LIBELF_SET_ERROR(ARGUMENT, 0);
116		return (NULL);
117	}
118
119	if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) {
120		LIBELF_SET_ERROR(SEQUENCE, 0);
121		return (NULL);
122	}
123
124	assert(e->e_class == ec);
125	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
126	assert(e->e_version == EV_CURRENT);
127
128	msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version);
129
130	assert(msz > 0);
131
132	newphdr = NULL;
133	if (count > 0 && (newphdr = calloc(count, msz)) == NULL) {
134		LIBELF_SET_ERROR(RESOURCE, 0);
135		return (NULL);
136	}
137
138	if (ec == ELFCLASS32) {
139		if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
140			free(oldphdr);
141		e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr;
142	} else {
143		if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
144			free(oldphdr);
145		e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr;
146	}
147
148	e->e_u.e_elf.e_nphdr = count;
149
150	elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);
151
152	return (newphdr);
153}
154