1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
/* Test program for adding a program header to a vendor specific ELF file.
Copyright (C) 2016 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
elfutils is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "system.h"
#include ELFUTILS_HEADER(elf)
#include <gelf.h>
void
check_elf (const char *fname, int class, int use_mmap)
{
printf ("\nfname: %s\n", fname);
int fd = open (fname, O_RDWR | O_CREAT | O_TRUNC, DEFFILEMODE);
if (fd == -1)
{
printf ("cannot open `%s': %s\n", fname, strerror (errno));
exit (1);
}
Elf *elf = elf_begin (fd, use_mmap ? ELF_C_WRITE_MMAP : ELF_C_WRITE, NULL);
if (elf == NULL)
{
printf ("cannot create ELF descriptor: %s\n", elf_errmsg (-1));
exit (1);
}
// Create an ELF header.
if (gelf_newehdr (elf, class) == 0)
{
printf ("cannot create ELF header: %s\n", elf_errmsg (-1));
exit (1);
}
GElf_Ehdr ehdr_mem;
GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
if (ehdr == NULL)
{
printf ("cannot get ELF header: %s\n", elf_errmsg (-1));
exit (1);
}
// Initialize header.
ehdr->e_ident[EI_DATA] = class == ELFCLASS64 ? ELFDATA2LSB : ELFDATA2MSB;
ehdr->e_ident[EI_OSABI] = ELFOSABI_GNU;
ehdr->e_type = ET_LOOS + 1;
ehdr->e_machine = EM_X86_64;
ehdr->e_version = EV_CURRENT;
if (gelf_update_ehdr (elf, ehdr) == 0)
{
printf ("cannot update ELF header: %s\n", elf_errmsg (-1));
exit (1);
}
// Create a program header.
if (gelf_newphdr (elf, 1) == 0)
{
printf ("cannot create program header: %s\n", elf_errmsg (-1));
exit (1);
}
GElf_Phdr phdr;
if (gelf_getphdr (elf, 0, &phdr) == NULL)
{
printf ("cannot get program header: %s\n", elf_errmsg (-1));
exit (1);
}
// Some random values to check later.
phdr.p_type = PT_NULL;
phdr.p_offset = 0;
phdr.p_vaddr = 0;
phdr.p_paddr = 1;
phdr.p_filesz = 0;
phdr.p_memsz = 1024;
phdr.p_flags = PF_R;
phdr.p_align = 16;
if (gelf_update_phdr (elf, 0, &phdr) == 0)
{
printf ("cannot update program header: %s\n", elf_errmsg (-1));
exit (1);
}
// Write everything to disk.
if (elf_update (elf, ELF_C_WRITE) < 0)
{
printf ("failure in elf_update(WRITE): %s\n", elf_errmsg (-1));
exit (1);
}
if (elf_end (elf) != 0)
{
printf ("failure in elf_end: %s\n", elf_errmsg (-1));
exit (1);
}
close (fd);
/* Reread the ELF from disk now. */
fd = open (fname, O_RDONLY);
if (fd == -1)
{
printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
exit (1);
}
elf = elf_begin (fd, use_mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL);
if (elf == NULL)
{
printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1));
exit (1);
}
// Is our phdr there?
size_t phnum;
if (elf_getphdrnum (elf, &phnum) != 0)
{
printf ("cannot get phdr num: %s\n", elf_errmsg (-1));
exit (1);
}
if (phnum != 1)
{
printf ("Expected just 1 phdr, got: %zd\n", phnum);
exit (1);
}
if (gelf_getphdr (elf, 0, &phdr) == NULL)
{
printf ("cannot get program header from file: %s\n", elf_errmsg (-1));
exit (1);
}
if (phdr.p_type != PT_NULL
|| phdr.p_offset != 0
|| phdr.p_vaddr != 0
|| phdr.p_paddr != 1
|| phdr.p_filesz != 0
|| phdr.p_memsz != 1024
|| phdr.p_flags != PF_R
|| phdr.p_align != 16)
{
printf ("Unexpected phdr values\n");
exit (1);
}
if (elf_end (elf) != 0)
{
printf ("failure in elf_end: %s\n", elf_errmsg (-1));
exit (1);
}
close (fd);
unlink (fname);
}
int
main (int argc __attribute__ ((unused)),
char *argv[] __attribute__ ((unused)))
{
elf_version (EV_CURRENT);
check_elf ("vendor.elf.32", ELFCLASS32, 0);
check_elf ("vendor.elf.32.mmap", ELFCLASS32, 1);
check_elf ("vendor.elf.64", ELFCLASS64, 0);
check_elf ("vendor.elf.64.mmap", ELFCLASS64, 1);
return 0;
}
|
