xref: /linux/scripts/mod/mk_elfconfig.c (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <string.h>
5 #include <elf.h>
6 
7 int
8 main(int argc, char **argv)
9 {
10 	unsigned char ei[EI_NIDENT];
11 	union { short s; char c[2]; } endian_test;
12 
13 	if (fread(ei, 1, EI_NIDENT, stdin) != EI_NIDENT) {
14 		fprintf(stderr, "Error: input truncated\n");
15 		return 1;
16 	}
17 	if (memcmp(ei, ELFMAG, SELFMAG) != 0) {
18 		fprintf(stderr, "Error: not ELF\n");
19 		return 1;
20 	}
21 	switch (ei[EI_CLASS]) {
22 	case ELFCLASS32:
23 		printf("#define KERNEL_ELFCLASS ELFCLASS32\n");
24 		break;
25 	case ELFCLASS64:
26 		printf("#define KERNEL_ELFCLASS ELFCLASS64\n");
27 		break;
28 	default:
29 		exit(1);
30 	}
31 	switch (ei[EI_DATA]) {
32 	case ELFDATA2LSB:
33 		printf("#define KERNEL_ELFDATA ELFDATA2LSB\n");
34 		break;
35 	case ELFDATA2MSB:
36 		printf("#define KERNEL_ELFDATA ELFDATA2MSB\n");
37 		break;
38 	default:
39 		exit(1);
40 	}
41 
42 	if (sizeof(unsigned long) == 4) {
43 		printf("#define HOST_ELFCLASS ELFCLASS32\n");
44 	} else if (sizeof(unsigned long) == 8) {
45 		printf("#define HOST_ELFCLASS ELFCLASS64\n");
46 	}
47 
48 	endian_test.s = 0x0102;
49 	if (memcmp(endian_test.c, "\x01\x02", 2) == 0)
50 		printf("#define HOST_ELFDATA ELFDATA2MSB\n");
51 	else if (memcmp(endian_test.c, "\x02\x01", 2) == 0)
52 		printf("#define HOST_ELFDATA ELFDATA2LSB\n");
53 	else
54 		exit(1);
55 
56 	return 0;
57 }
58