libelf_phdr.c revision 4484 
1/*-
2 * Copyright (c) 2006 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 * $FreeBSD: src/lib/libelf/libelf_phdr.c,v 1.2 2006/12/25 02:22:22 jkoshy Exp $
27 */
28
29#include <assert.h>
30#include <stdlib.h>
31
32#include "gelf.h"
33#include "libelf.h"
34#include "_libelf.h"
35
36void *
37_libelf_getphdr(Elf *e, int ec)
38{
39        size_t phnum, phentsize;
40        size_t fsz, msz;
41        uint64_t phoff;
42        Elf32_Ehdr *eh32;
43        Elf64_Ehdr *eh64;
44        void *ehdr, *phdr;
45        void (*xlator)(char *_d, char *_s, size_t _c, int _swap);
46
47        assert(ec == ELFCLASS32 || ec == ELFCLASS64);
48
49        if (e == NULL) {
50                LIBELF_SET_ERROR(ARGUMENT, 0);
51                return (NULL);
52        }
53
54        if ((phdr = (ec == ELFCLASS32 ?
55                 (void *) e->e_u.e_elf.e_phdr.e_phdr32 :
56                 (void *) e->e_u.e_elf.e_phdr.e_phdr64)) != NULL)
57                return (phdr);
58
59        /*
60         * Check the PHDR related fields in the EHDR for sanity.
61         */
62
63        if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
64                return (NULL);
65
66        phnum = e->e_u.e_elf.e_nphdr;
67
68        if (ec == ELFCLASS32) {
69                eh32      = (Elf32_Ehdr *) ehdr;
70                phentsize = eh32->e_phentsize;
71                phoff     = (uint64_t) eh32->e_phoff;
72        } else {
73                eh64      = (Elf64_Ehdr *) ehdr;
74                phentsize = eh64->e_phentsize;
75                phoff     = (uint64_t) eh64->e_phoff;
76        }
77
78        fsz = gelf_fsize(e, ELF_T_PHDR, phnum, e->e_version);
79
80        assert(fsz > 0);
81
82        if ((uint64_t) e->e_rawsize < (phoff + fsz)) {
83                LIBELF_SET_ERROR(HEADER, 0);
84                return (NULL);
85        }
86
87        msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT);
88
89        assert(msz > 0);
90
91        if ((phdr = calloc(phnum, msz)) == NULL) {
92                LIBELF_SET_ERROR(RESOURCE, 0);
93                return (NULL);
94        }
95
96        if (ec == ELFCLASS32)
97                e->e_u.e_elf.e_phdr.e_phdr32 = phdr;
98        else
99                e->e_u.e_elf.e_phdr.e_phdr64 = phdr;
100
101
102        xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec);
103        (*xlator)(phdr, e->e_rawfile + phoff, phnum,
104            e->e_byteorder != LIBELF_PRIVATE(byteorder));
105
106        return (phdr);
107}
108
109void *
110_libelf_newphdr(Elf *e, int ec, size_t count)
111{
112        void *ehdr, *newphdr, *oldphdr;
113        size_t msz;
114
115        if (e == NULL) {
116                LIBELF_SET_ERROR(ARGUMENT, 0);
117                return (NULL);
118        }
119
120        if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) {
121                LIBELF_SET_ERROR(SEQUENCE, 0);
122                return (NULL);
123        }
124
125        assert(e->e_class == ec);
126        assert(ec == ELFCLASS32 || ec == ELFCLASS64);
127        assert(e->e_version == EV_CURRENT);
128
129        msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version);
130
131        assert(msz > 0);
132
133        newphdr = NULL;
134        if (count > 0 && (newphdr = calloc(count, msz)) == NULL) {
135                LIBELF_SET_ERROR(RESOURCE, 0);
136                return (NULL);
137        }
138
139        if (ec == ELFCLASS32) {
140                if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
141                        free(oldphdr);
142                e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr;
143        } else {
144                if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
145                        free(oldphdr);
146                e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr;
147        }
148
149        e->e_u.e_elf.e_nphdr = count;
150
151        elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);
152
153        return (newphdr);
154}
155