1 /* Test program for adding a program header to a vendor specific ELF file.
2 Copyright (C) 2016 Red Hat, Inc.
3 This file is part of elfutils.
4
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 elfutils is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17
18
19 #ifdef HAVE_CONFIG_H
20 # include <config.h>
21 #endif
22
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <inttypes.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30
31 #include ELFUTILS_HEADER(elf)
32 #include <gelf.h>
33
34 void
check_elf(const char * fname,int class,int use_mmap)35 check_elf (const char *fname, int class, int use_mmap)
36 {
37 printf ("\nfname: %s\n", fname);
38
39 int fd = open (fname, O_RDWR | O_CREAT | O_TRUNC, 0666);
40 if (fd == -1)
41 {
42 printf ("cannot open `%s': %s\n", fname, strerror (errno));
43 exit (1);
44 }
45
46 Elf *elf = elf_begin (fd, use_mmap ? ELF_C_WRITE_MMAP : ELF_C_WRITE, NULL);
47 if (elf == NULL)
48 {
49 printf ("cannot create ELF descriptor: %s\n", elf_errmsg (-1));
50 exit (1);
51 }
52
53 // Create an ELF header.
54 if (gelf_newehdr (elf, class) == 0)
55 {
56 printf ("cannot create ELF header: %s\n", elf_errmsg (-1));
57 exit (1);
58 }
59
60 GElf_Ehdr ehdr_mem;
61 GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
62 if (ehdr == NULL)
63 {
64 printf ("cannot get ELF header: %s\n", elf_errmsg (-1));
65 exit (1);
66 }
67
68 // Initialize header.
69 ehdr->e_ident[EI_DATA] = class == ELFCLASS64 ? ELFDATA2LSB : ELFDATA2MSB;
70 ehdr->e_ident[EI_OSABI] = ELFOSABI_GNU;
71 ehdr->e_type = ET_LOOS + 1;
72 ehdr->e_machine = EM_X86_64;
73 ehdr->e_version = EV_CURRENT;
74
75 if (gelf_update_ehdr (elf, ehdr) == 0)
76 {
77 printf ("cannot update ELF header: %s\n", elf_errmsg (-1));
78 exit (1);
79 }
80
81 // Create a program header.
82 if (gelf_newphdr (elf, 1) == 0)
83 {
84 printf ("cannot create program header: %s\n", elf_errmsg (-1));
85 exit (1);
86 }
87
88 GElf_Phdr phdr;
89 if (gelf_getphdr (elf, 0, &phdr) == NULL)
90 {
91 printf ("cannot get program header: %s\n", elf_errmsg (-1));
92 exit (1);
93 }
94
95 // Some random values to check later.
96 phdr.p_type = PT_NULL;
97 phdr.p_offset = 0;
98 phdr.p_vaddr = 0;
99 phdr.p_paddr = 1;
100 phdr.p_filesz = 0;
101 phdr.p_memsz = 1024;
102 phdr.p_flags = PF_R;
103 phdr.p_align = 16;
104
105 if (gelf_update_phdr (elf, 0, &phdr) == 0)
106 {
107 printf ("cannot update program header: %s\n", elf_errmsg (-1));
108 exit (1);
109 }
110
111 // Write everything to disk.
112 if (elf_update (elf, ELF_C_WRITE) < 0)
113 {
114 printf ("failure in elf_update(WRITE): %s\n", elf_errmsg (-1));
115 exit (1);
116 }
117
118 if (elf_end (elf) != 0)
119 {
120 printf ("failure in elf_end: %s\n", elf_errmsg (-1));
121 exit (1);
122 }
123
124 close (fd);
125
126 /* Reread the ELF from disk now. */
127 fd = open (fname, O_RDONLY, 0666);
128 if (fd == -1)
129 {
130 printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
131 exit (1);
132 }
133
134 elf = elf_begin (fd, use_mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL);
135 if (elf == NULL)
136 {
137 printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1));
138 exit (1);
139 }
140
141 // Is our phdr there?
142 size_t phnum;
143 if (elf_getphdrnum (elf, &phnum) != 0)
144 {
145 printf ("cannot get phdr num: %s\n", elf_errmsg (-1));
146 exit (1);
147 }
148
149 if (phnum != 1)
150 {
151 printf ("Expected just 1 phdr, got: %zd\n", phnum);
152 exit (1);
153 }
154
155 if (gelf_getphdr (elf, 0, &phdr) == NULL)
156 {
157 printf ("cannot get program header from file: %s\n", elf_errmsg (-1));
158 exit (1);
159 }
160
161 if (phdr.p_type != PT_NULL
162 || phdr.p_offset != 0
163 || phdr.p_vaddr != 0
164 || phdr.p_paddr != 1
165 || phdr.p_filesz != 0
166 || phdr.p_memsz != 1024
167 || phdr.p_flags != PF_R
168 || phdr.p_align != 16)
169 {
170 printf ("Unexpected phdr values\n");
171 exit (1);
172 }
173
174 if (elf_end (elf) != 0)
175 {
176 printf ("failure in elf_end: %s\n", elf_errmsg (-1));
177 exit (1);
178 }
179
180 close (fd);
181
182 unlink (fname);
183 }
184
185 int
main(int argc,char * argv[])186 main (int argc __attribute__ ((unused)),
187 char *argv[] __attribute__ ((unused)))
188 {
189 elf_version (EV_CURRENT);
190
191 check_elf ("vendor.elf.32", ELFCLASS32, 0);
192 check_elf ("vendor.elf.32.mmap", ELFCLASS32, 1);
193 check_elf ("vendor.elf.64", ELFCLASS64, 0);
194 check_elf ("vendor.elf.64.mmap", ELFCLASS64, 1);
195
196 return 0;
197 }
198