/*
* This program was advertised on unix-wizards.  I have had such a large
* response I'm sending it out to the world.
*
* Here is the source.  It works fine under 4.1bsd, I see no fundamental
* reason why it shouldn't work on an 11. (Except possibly small format
* changes in exec header or user structure.)  No documentation yet.
* Usage is
*        undump new-a.out-file [old-a.out-file] [core-file]
* where old-a.out-file and core-file default to "a.out" and "core",
* respectively.  Probably should have an option to not require
* old-a.out-file if the core came from a 407 file.
*
* It doesn't preserve open files, and the program is re-entered at main
* when you run it.  It's used locally to dump a lisp and restart it.
*
* It requires a local subroutine called scanargs, somewhat similar to
* getopt (I think).  You should be able to easily get around this, though.
* =Spencer
*/


/*
* undump.c - Convert a core file to an a.out.
*
* Author:      Spencer W. Thomas
*              Computer Science Dept.
*              University of Utah
* Date:        Wed Feb 17 1982
* Copyright (c) 1982 Spencer W. Thomas
*
* Usage:
* undump new-a.out [a.out] [core]
*/

#include <stdio.h>
#include <sys/param.h>
#include <sys/dir.h>
#include <sys/stat.h>
#include <aouthdr.h>
#include <filehdr.h>
#include <scnhdr.h>
#include <linenum.h>
#include <sys/ptrace.h>

#define PSIZE       10240
#define MAXSCNS         8

struct ptrace_user u;
AOUTHDR ahdr, oahdr;
struct filehdr fhdr, ofhdr;
struct scnhdr  scns[MAXSCNS];
int    nscns;
long cur_pos, sym_top;


main(argc, argv)
char **argv;
{
   char *new_name, *a_out_name = "a.out", *core_name = "core";
   FILE *new, *a_out, *core;

   if (scanargs(argc, argv, "undump new-a.out!s a.out%s core%s",
           &new_name, &a_out_name, &core_name)
                   != 1)
       exit(1);

   if ((a_out = fopen(a_out_name, "r")) == NULL)
   {
       perror(a_out_name);
       exit(1);
   }
   if ((core = fopen(core_name, "r")) == NULL)
   {
       perror(core_name);
       exit(1);
   }
   if ((new = fopen(new_name, "w")) == NULL)
   {
       perror(new_name);
       exit(1);
   }

   read_u(core);
   make_hdr(new, a_out);
   copy_text(new, a_out);
   copy_data(new, core);
   copy_sym(new, a_out);
   fclose(new);
   fclose(core);
   fclose(a_out);
   mark_x(new_name);
}

/*
* read the u structure from the core file.
*/
read_u(core)
FILE *core;
{
   if ( fread(&u, sizeof u, 1, core) != 1 )
   {
       perror("Couldn't read user structure from core file");
       exit(1);
   }
}

/*
* Make the header in the new a.out from the header in the old one
* modified by the new data size.
*/
make_hdr(new, a_out)
FILE *new, *a_out;
{

       int i;

/* sym_top points to the beginning of the line#/sym/str data */

/*
*  read file header from a.out
*/

   if (fread(&fhdr, sizeof fhdr, 1, a_out) != 1)
   {
       perror("Couldn't read file header from a.out file");
       exit(1);
   }

/*
*  read system header from a.out COFF format
*/

   if (fhdr.f_opthdr > 0)
   {
       if (fread(&ahdr, sizeof ahdr, 1, a_out) != 1)
       {
           perror("Couldn't read system file header from a.out file");
           exit(1);
       }

/*
*  read section headers from a.out COFF format
*/

       nscns = fhdr.f_nscns;
       for(i=0;(i != nscns);i++) {
           if (fread(&scns[i], sizeof(struct scnhdr), 1, a_out) != 1) {
               perror("Couldn't read section headers from a.out file");
               exit(1);
               }
           }
   }


/*    if N_BADMAG(hdr)
   {
       fprintf(stderr, "a.out file doesn't have legal magic number\n");
       exit(1);
   } */



   if (ahdr.magic != u.pt_aouthdr.magic ||
       ahdr.tsize != u.pt_aouthdr.tsize ||
       ahdr.dsize != u.pt_aouthdr.dsize ||
       ahdr.entry != u.pt_aouthdr.entry)
   {
       fprintf(stderr, "Core file didn't come from this a.out\n");
       exit(1);
   }

   printf("Data segment size was %u", ahdr.dsize);
   ahdr.dsize = u.pt_dsize;
   ahdr.bsize = 0;                     /* all data is inited now! */
   printf(" now is %u\n", ahdr.dsize);


/*
*  point to top of old line#/symbol/string info if there is any so
*  we can find it later...
*/

   sym_top = 0;
   if (scns[0].s_nlnno != 0)
       sym_top = scns[0].s_lnnoptr;
   else if (fhdr.f_nsyms != 0)
       sym_top = fhdr.f_symptr;

   scns[1].s_size = u.pt_dsize;
   scns[2].s_size = 0;
   scns[2].s_vaddr = 0;
   scns[2].s_paddr = 0;

   cur_pos = scns[1].s_scnptr + scns[1].s_size;

   if (scns[0].s_nlnno != 0) {
       scns[0].s_lnnoptr = cur_pos;
       cur_pos += scns[0].s_nlnno * sizeof(struct lineno);
       }
   if (fhdr.f_nsyms != 0) {
       fhdr.f_symptr = cur_pos;
       }




   if (fwrite(&fhdr, sizeof fhdr, 1, new) != 1)
   {
       perror("Couldn't write file header to new a.out file");
       exit(1);
   }
   if (fhdr.f_opthdr > 0)
   {
       if (fwrite(&ahdr, sizeof ahdr, 1, new) != 1)
       {
           perror("Couldn't write system file header to new a.out file");
           exit(1);
       }
       for(i=0;(i != nscns);i++) {
           if (fwrite(&scns[i], sizeof(struct scnhdr), 1, new) != 1) {
               perror("Couldn't write section headers to new a.out file");
               exit(1);
               }
           }
   }

}

/*
* Copy the text from the a.out to the new a.out
*/
copy_text(new, a_out)
FILE *new, *a_out;
{
   char page[PSIZE];
   int txtcnt;

   txtcnt = ahdr.tsize;

   fseek(new, scns[0].s_scnptr, 0);
   fseek(a_out, scns[0].s_scnptr, 0);

/*    if (hdr.a_magic == OMAGIC)
   {
       printf("a.out file is not shared text, getting text from core file\n");
       fseek(a_out, hdr.a_text, 1);    * skip over text *
       return;
   } */


   while (txtcnt >= PSIZE)
   {
       if (fread(page, PSIZE, 1, a_out) != 1)
       {
           perror("Read failure on a.out text");
           exit(1);
       }
       if (fwrite(page, PSIZE, 1, new) != 1)
       {
           perror("Write failure in text segment");
           exit(1);
       }
       txtcnt -= PSIZE;
   }
   if (txtcnt)
   {
       if (fread(page, txtcnt, 1, a_out) != 1)
       {
           perror("Read failure on a.out text");
           exit(1);
       }
       if (fwrite(page, txtcnt, 1, new) != 1)
       {
           perror("Write failure in text segment");
           exit(1);
       }
   }
}

/*
* copy the data from the core file to the new a.out
*/
copy_data(new, core)
FILE *new, *core;
{
   char page[PSIZE];
   int datacnt;


   datacnt = u.pt_dsize;

/*    if (hdr.a_magic == OMAGIC)
       datacnt += u.u_tsize; */
   fseek(core,(long) sizeof(struct ptrace_user), 0);
   fseek(new, scns[1].s_scnptr, 0);
   while (datacnt >= PSIZE)
   {
       if (fread(page, PSIZE, 1, core) != 1)
       {
           perror("Read failure on core data");
           exit(1);
       }
       if (fwrite(page, PSIZE, 1, new) != 1)
       {
           perror("Write failure in data segment");
           exit(1);
       }
       datacnt -= PSIZE;
   }
   if (datacnt)
   {
       if (fread(page, datacnt, 1, core) != 1)
       {
           perror("Read failure on core data");
           exit(1);
       }
       if (fwrite(page, datacnt, 1, new) != 1)
       {
           perror("Write failure in data segment");
           exit(1);
       }
   }
}

/*
* Copy the relocation information and symbol table from the a.out to the new
*/
copy_sym(new, a_out)
FILE *new, *a_out;
{
   char page[PSIZE];
   int n;

   fseek(a_out, sym_top, 0);   /* skip over data segment */
   while ((n = fread(page, 1, PSIZE, a_out)) > 0)
   {
       if (fwrite(page, 1, n, new) != n)
       {
           perror("Error writing symbol table to new a.out");
           fprintf(stderr, "new a.out should be ok otherwise\n");
           return;
       }
   }
   if (n < 0)
   {
       perror("Error reading symbol table from a.out");
       fprintf(stderr, "new a.out should be ok otherwise\n");
   }
}

/*
* After succesfully building the new a.out, mark it executable
*/
mark_x(name)
char *name;
{
   struct stat sbuf;
   int um;

   um = umask(777);
   umask(um);
   if (stat(name, &sbuf) == -1)
   {
       perror ("Can't stat new a.out");
       fprintf(stderr, "Setting protection to %o\n", 0777 & ~um);
       sbuf.st_mode = 0777;
   }
   sbuf.st_mode |= 0111 & ~um;
   if (chmod(name, sbuf.st_mode) == -1)
       perror("Couldn't change mode of new a.out to executable");

}

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