src/unexencap.c

   1 /* Waiting for papers!  */
   2
   3 /*
   4  * Do an unexec() for coff encapsulation. Uses the approach I took
   5  * for AKCL, so don't be surprised if it doesn't look too much like
   6  * the other unexec() routines. Assumes NO_REMAP. Should be easy to
   7  * adapt to the emacs style unexec() if that is desired, but this works
   8  * just fine for me with GCC/GAS/GLD under System V.  - Jordan
   9  */
  10
  11 #include <sys/types.h>
  12 #include <sys/fcntl.h>
  13 #include <sys/file.h>
  14 #include <stdio.h>
  15 #include "/usr/gnu/lib/gcc/gcc-include/a.out.h"
  16
  17 filecpy(to, from, n)
  18 FILE *to, *from;
  19 register int n;
  20 {
  21         char buffer[BUFSIZ];
  22
  23         for (;;)
  24                 if (n > BUFSIZ) {
  25                         fread(buffer, BUFSIZ, 1, from);
  26                         fwrite(buffer, BUFSIZ, 1, to);
  27                         n -= BUFSIZ;
  28                 } else if (n > 0) {
  29                         fread(buffer, 1, n, from);
  30                         fwrite(buffer, 1, n, to);
  31                         break;
  32                 } else
  33                         break;
  34 }
  35 /* ****************************************************************
  36  * unexec
  37  *
  38  * driving logic.
  39  * ****************************************************************/
  40 unexec (new_name, a_name, data_start, bss_start, entry_address)
  41 char *new_name, *a_name;
  42 unsigned data_start, bss_start, entry_address;
  43 {
  44         struct coffheader header1;
  45         struct coffscn *tp, *dp, *bp;
  46         struct exec header;
  47         int stsize;
  48         char *original_file = a_name;
  49         char *save_file = new_name;
  50
  51         char *data_begin, *data_end;
  52         int original_data;
  53         FILE *original, *save;
  54         register int n;
  55         register char *p;
  56         extern char *sbrk();
  57         char stdin_buf[BUFSIZ], stdout_buf[BUFSIZ];
  58
  59
  60         fclose(stdin);
  61         original = fopen(original_file, "r");
  62         if (stdin != original || original->_file != 0) {
  63                 fprintf(stderr, "unexec: Can't open the original file.\n");
  64                 exit(1);
  65         }
  66         setbuf(original, stdin_buf);
  67         fclose(stdout);
  68         unlink(save_file);
  69         n = open(save_file, O_CREAT|O_WRONLY, 0777);
  70         if (n != 1 || (save = fdopen(n, "w")) != stdout) {
  71                 fprintf(stderr, "unexec: Can't open the save file.\n");
  72                 exit(1);
  73         }
  74         setbuf(save, stdout_buf);
  75
  76         fread(&header1, sizeof(header1), 1, original);
  77         tp = &header1.scns[0];
  78         dp = &header1.scns[1];
  79         bp = &header1.scns[2];
  80         fread(&header, sizeof(header), 1, original);
  81         data_begin=(char *)N_DATADDR(header);
  82         data_end = sbrk(0);
  83         original_data = header.a_data;
  84         header.a_data = data_end - data_begin;
  85         header.a_bss = 0;
  86         dp->s_size = header.a_data;
  87         bp->s_paddr = dp->s_vaddr + dp->s_size;
  88         bp->s_vaddr = bp->s_paddr;
  89         bp->s_size = 0;
  90         header1.tsize = tp->s_size;
  91         header1.dsize = dp->s_size;
  92         header1.bsize = bp->s_size;
  93         fwrite(&header1, sizeof(header1), 1, save);
  94         fwrite(&header, sizeof(header), 1, save);
  95
  96         filecpy(save, original, header.a_text);
  97
  98         for (n = header.a_data, p = data_begin;  ;  n -= BUFSIZ, p += BUFSIZ)
  99                 if (n > BUFSIZ)
 100                         fwrite(p, BUFSIZ, 1, save);
 101                 else if (n > 0) {
 102                         fwrite(p, 1, n, save);
 103                         break;
 104                 } else
 105                         break;
 106
 107         fseek(original, original_data, 1);
 108
 109         filecpy(save, original, header.a_syms+header.a_trsize+header.a_drsize);
 110         fread(&stsize, sizeof(stsize), 1, original);
 111         fwrite(&stsize, sizeof(stsize), 1, save);
 112         filecpy(save, original, stsize - sizeof(stsize));
 113
 114         fclose(original);
 115         fclose(save);
 116 }