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 #include "system.h"
31
32 #include ELFUTILS_HEADER(elf)
33 #include <gelf.h>
34
35 void
check_elf(const char * fname,int class,int use_mmap)36 check_elf (const char *fname, int class, int use_mmap)
37 {
38 printf ("\nfname: %s\n", fname);
39
40 int fd = open (fname, O_RDWR | O_CREAT | O_TRUNC, DEFFILEMODE);
41 if (fd == -1)
42 {
43 printf ("cannot open `%s': %s\n", fname, strerror (errno));
44 exit (1);
45 }
46
47 Elf *elf = elf_begin (fd, use_mmap ? ELF_C_WRITE_MMAP : ELF_C_WRITE, NULL);
48 if (elf == NULL)
49 {
50 printf ("cannot create ELF descriptor: %s\n", elf_errmsg (-1));
51 exit (1);
52 }
53
54 // Create an ELF header.
55 if (gelf_newehdr (elf, class) == 0)
56 {
57 printf ("cannot create ELF header: %s\n", elf_errmsg (-1));
58 exit (1);
59 }
60
61 GElf_Ehdr ehdr_mem;
62 GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
63 if (ehdr == NULL)
64 {
65 printf ("cannot get ELF header: %s\n", elf_errmsg (-1));
66 exit (1);
67 }
68
69 // Initialize header.
70 ehdr->e_ident[EI_DATA] = class == ELFCLASS64 ? ELFDATA2LSB : ELFDATA2MSB;
71 ehdr->e_ident[EI_OSABI] = ELFOSABI_GNU;
72 ehdr->e_type = ET_LOOS + 1;
73 ehdr->e_machine = EM_X86_64;
74 ehdr->e_version = EV_CURRENT;
75
76 if (gelf_update_ehdr (elf, ehdr) == 0)
77 {
78 printf ("cannot update ELF header: %s\n", elf_errmsg (-1));
79 exit (1);
80 }
81
82 // Create a program header.
83 if (gelf_newphdr (elf, 1) == 0)
84 {
85 printf ("cannot create program header: %s\n", elf_errmsg (-1));
86 exit (1);
87 }
88
89 GElf_Phdr phdr;
90 if (gelf_getphdr (elf, 0, &phdr) == NULL)
91 {
92 printf ("cannot get program header: %s\n", elf_errmsg (-1));
93 exit (1);
94 }
95
96 // Some random values to check later.
97 phdr.p_type = PT_NULL;
98 phdr.p_offset = 0;
99 phdr.p_vaddr = 0;
100 phdr.p_paddr = 1;
101 phdr.p_filesz = 0;
102 phdr.p_memsz = 1024;
103 phdr.p_flags = PF_R;
104 phdr.p_align = 16;
105
106 if (gelf_update_phdr (elf, 0, &phdr) == 0)
107 {
108 printf ("cannot update program header: %s\n", elf_errmsg (-1));
109 exit (1);
110 }
111
112 // Write everything to disk.
113 if (elf_update (elf, ELF_C_WRITE) < 0)
114 {
115 printf ("failure in elf_update(WRITE): %s\n", elf_errmsg (-1));
116 exit (1);
117 }
118
119 if (elf_end (elf) != 0)
120 {
121 printf ("failure in elf_end: %s\n", elf_errmsg (-1));
122 exit (1);
123 }
124
125 close (fd);
126
127 /* Reread the ELF from disk now. */
128 fd = open (fname, O_RDONLY);
129 if (fd == -1)
130 {
131 printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
132 exit (1);
133 }
134
135 elf = elf_begin (fd, use_mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL);
136 if (elf == NULL)
137 {
138 printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1));
139 exit (1);
140 }
141
142 // Is our phdr there?
143 size_t phnum;
144 if (elf_getphdrnum (elf, &phnum) != 0)
145 {
146 printf ("cannot get phdr num: %s\n", elf_errmsg (-1));
147 exit (1);
148 }
149
150 if (phnum != 1)
151 {
152 printf ("Expected just 1 phdr, got: %zd\n", phnum);
153 exit (1);
154 }
155
156 if (gelf_getphdr (elf, 0, &phdr) == NULL)
157 {
158 printf ("cannot get program header from file: %s\n", elf_errmsg (-1));
159 exit (1);
160 }
161
162 if (phdr.p_type != PT_NULL
163 || phdr.p_offset != 0
164 || phdr.p_vaddr != 0
165 || phdr.p_paddr != 1
166 || phdr.p_filesz != 0
167 || phdr.p_memsz != 1024
168 || phdr.p_flags != PF_R
169 || phdr.p_align != 16)
170 {
171 printf ("Unexpected phdr values\n");
172 exit (1);
173 }
174
175 if (elf_end (elf) != 0)
176 {
177 printf ("failure in elf_end: %s\n", elf_errmsg (-1));
178 exit (1);
179 }
180
181 close (fd);
182
183 unlink (fname);
184 }
185
186 int
main(int argc,char * argv[])187 main (int argc __attribute__ ((unused)),
188 char *argv[] __attribute__ ((unused)))
189 {
190 elf_version (EV_CURRENT);
191
192 check_elf ("vendor.elf.32", ELFCLASS32, 0);
193 check_elf ("vendor.elf.32.mmap", ELFCLASS32, 1);
194 check_elf ("vendor.elf.64", ELFCLASS64, 0);
195 check_elf ("vendor.elf.64.mmap", ELFCLASS64, 1);
196
197 return 0;
198 }
199