root/arch/i386/boot/compressed/piggyback.c

/* */

DEFINITIONS

1. main

   1 /*
   2  *      linux/zBoot/piggyback.c
   3  *
   4  *      (C) 1993 Hannu Savolainen
   5  */
   6 
   7 /*
   8  *      This program reads the compressed system image from stdin and
   9  *      encapsulates it into an object file written to the stdout.
  10  */
  11 
  12 #include <stdio.h>
  13 #include <unistd.h>
  14 #include <a.out.h>
  15 
  16 int main(int argc, char *argv[])
     /*  */
  17 {
  18         int c, n=0, len=0;
  19         char tmp_buf[512*1024];
  20         
  21         struct exec obj = {0x00640107}; /* object header */
  22         char string_names[] = {"_input_data\0_input_len\0"};
  23 
  24         struct nlist var_names[2] = /* Symbol table */
  25                 {       
  26                         {       /* _input_data  */
  27                                 (char *)4, 7, 0, 0, 0
  28                         },
  29                         {       /* _input_len */
  30                                 (char *)16, 7, 0, 0, 0
  31                         }
  32                 };
  33 
  34 
  35         len = 0;
  36         while ((n = read(0, &tmp_buf[len], sizeof(tmp_buf)-len+1)) > 0)
  37               len += n;
  38 
  39         if (n==-1)
  40         {
  41                 perror("stdin");
  42                 exit(-1);
  43         }
  44 
  45         if (len >= sizeof(tmp_buf))
  46         {
  47                 fprintf(stderr, "%s: Input too large\n", argv[0]);
  48                 exit(-1);
  49         }
  50 
  51         fprintf(stderr, "Compressed size %d.\n", len);
  52 
  53 /*
  54  *      Output object header
  55  */
  56         obj.a_data = len + sizeof(long);
  57         obj.a_syms = sizeof(var_names);
  58         write(1, (char *)&obj, sizeof(obj));
  59 
  60 /*
  61  *      Output data segment (compressed system & len)
  62  */
  63         write(1, tmp_buf, len);
  64         write(1, (char *)&len, sizeof(len));
  65 
  66 /*
  67  *      Output symbol table
  68  */
  69         var_names[1].n_value = len;
  70         write(1, (char *)&var_names, sizeof(var_names));
  71 
  72 /*
  73  *      Output string table
  74  */
  75         len = sizeof(string_names) + sizeof(len);
  76         write(1, (char *)&len, sizeof(len));
  77         write(1, string_names, sizeof(string_names));
  78 
  79         exit(0);
  80 
  81 }

/* */