libelf_phdr.c revision 276371 
11590Srgrimes/*-
283391Sru * Copyright (c) 2006,2008 Joseph Koshy
31590Srgrimes * All rights reserved.
41590Srgrimes *
583391Sru * Redistribution and use in source and binary forms, with or without
6207736Smckusick * modification, are permitted provided that the following conditions
71590Srgrimes * are met:
8275042Sbapt * 1. Redistributions of source code must retain the above copyright
913236Sgraichen *    notice, this list of conditions and the following disclaimer.
101590Srgrimes * 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 <sys/cdefs.h>
28
29#include <assert.h>
30#include <gelf.h>
31#include <libelf.h>
32#include <stdlib.h>
33
34#include "_libelf.h"
35
36ELFTC_VCSID("$Id: libelf_phdr.c 3009 2014-03-23 01:49:59Z jkoshy $");
37
38void *
39_libelf_getphdr(Elf *e, int ec)
40{
41	size_t phnum;
42	size_t fsz, msz;
43	uint64_t phoff;
44	Elf32_Ehdr *eh32;
45	Elf64_Ehdr *eh64;
46	void *ehdr, *phdr;
47	int (*xlator)(unsigned char *_d, size_t _dsz, unsigned char *_s,
48	    size_t _c, int _swap);
49
50	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
51
52	if (e == NULL) {
53		LIBELF_SET_ERROR(ARGUMENT, 0);
54		return (NULL);
55	}
56
57	if ((phdr = (ec == ELFCLASS32 ?
58		 (void *) e->e_u.e_elf.e_phdr.e_phdr32 :
59		 (void *) e->e_u.e_elf.e_phdr.e_phdr64)) != NULL)
60		return (phdr);
61
62	/*
63	 * Check the PHDR related fields in the EHDR for sanity.
64	 */
65
66	if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
67		return (NULL);
68
69	phnum = e->e_u.e_elf.e_nphdr;
70
71	if (ec == ELFCLASS32) {
72		eh32      = (Elf32_Ehdr *) ehdr;
73		phoff     = (uint64_t) eh32->e_phoff;
74	} else {
75		eh64      = (Elf64_Ehdr *) ehdr;
76		phoff     = (uint64_t) eh64->e_phoff;
77	}
78
79	fsz = gelf_fsize(e, ELF_T_PHDR, phnum, e->e_version);
80
81	assert(fsz > 0);
82
83	if ((uint64_t) e->e_rawsize < (phoff + fsz)) {
84		LIBELF_SET_ERROR(HEADER, 0);
85		return (NULL);
86	}
87
88	msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT);
89
90	assert(msz > 0);
91
92	if ((phdr = calloc(phnum, msz)) == NULL) {
93		LIBELF_SET_ERROR(RESOURCE, 0);
94		return (NULL);
95	}
96
97	if (ec == ELFCLASS32)
98		e->e_u.e_elf.e_phdr.e_phdr32 = phdr;
99	else
100		e->e_u.e_elf.e_phdr.e_phdr64 = phdr;
101
102
103	xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec);
104	(*xlator)(phdr, phnum * msz, e->e_rawfile + phoff, phnum,
105	    e->e_byteorder != LIBELF_PRIVATE(byteorder));
106
107	return (phdr);
108}
109
110void *
111_libelf_newphdr(Elf *e, int ec, size_t count)
112{
113	void *ehdr, *newphdr, *oldphdr;
114	size_t msz;
115
116	if (e == NULL) {
117		LIBELF_SET_ERROR(ARGUMENT, 0);
118		return (NULL);
119	}
120
121	if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) {
122		LIBELF_SET_ERROR(SEQUENCE, 0);
123		return (NULL);
124	}
125
126	assert(e->e_class == ec);
127	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
128	assert(e->e_version == EV_CURRENT);
129
130	msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version);
131
132	assert(msz > 0);
133
134	newphdr = NULL;
135	if (count > 0 && (newphdr = calloc(count, msz)) == NULL) {
136		LIBELF_SET_ERROR(RESOURCE, 0);
137		return (NULL);
138	}
139
140	if (ec == ELFCLASS32) {
141		if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
142			free(oldphdr);
143		e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr;
144	} else {
145		if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
146			free(oldphdr);
147		e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr;
148	}
149
150	e->e_u.e_elf.e_nphdr = count;
151
152	elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);
153
154	return (newphdr);
155}
156