scripts/mod/mk_elfconfig.c

   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