Linux Kernel  3.7.1
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mk_elfconfig.c
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1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
4 #include <elf.h>
5 
6 int
7 main(int argc, char **argv)
8 {
9  unsigned char ei[EI_NIDENT];
10  union { short s; char c[2]; } endian_test;
11 
12  if (fread(ei, 1, EI_NIDENT, stdin) != EI_NIDENT) {
13  fprintf(stderr, "Error: input truncated\n");
14  return 1;
15  }
16  if (memcmp(ei, ELFMAG, SELFMAG) != 0) {
17  fprintf(stderr, "Error: not ELF\n");
18  return 1;
19  }
20  switch (ei[EI_CLASS]) {
21  case ELFCLASS32:
22  printf("#define KERNEL_ELFCLASS ELFCLASS32\n");
23  break;
24  case ELFCLASS64:
25  printf("#define KERNEL_ELFCLASS ELFCLASS64\n");
26  break;
27  default:
28  exit(1);
29  }
30  switch (ei[EI_DATA]) {
31  case ELFDATA2LSB:
32  printf("#define KERNEL_ELFDATA ELFDATA2LSB\n");
33  break;
34  case ELFDATA2MSB:
35  printf("#define KERNEL_ELFDATA ELFDATA2MSB\n");
36  break;
37  default:
38  exit(1);
39  }
40 
41  if (sizeof(unsigned long) == 4) {
42  printf("#define HOST_ELFCLASS ELFCLASS32\n");
43  } else if (sizeof(unsigned long) == 8) {
44  printf("#define HOST_ELFCLASS ELFCLASS64\n");
45  }
46 
47  endian_test.s = 0x0102;
48  if (memcmp(endian_test.c, "\x01\x02", 2) == 0)
49  printf("#define HOST_ELFDATA ELFDATA2MSB\n");
50  else if (memcmp(endian_test.c, "\x02\x01", 2) == 0)
51  printf("#define HOST_ELFDATA ELFDATA2LSB\n");
52  else
53  exit(1);
54 
55  return 0;
56 }
57