/* Low level interface to ptrace, for GDB when running under Unix.
   Copyright (C) 1986, 1987, 1989, 1991 Free Software Foundation, Inc.

This file is part of GDB.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include <stdio.h>
#include "defs.h"
#include "param.h"
#include "frame.h"
#include "inferior.h"

#include <sys/param.h>
#include <sys/dir.h>
#include <signal.h>
#include <sys/user.h>
#include <sys/ioctl.h>
#include <fcntl.h>

#include "gdbcore.h"

#include <sys/file.h>
#include <sys/stat.h>

/* Work with core dump and executable files, for GDB. 
   This code would be in core.c if it weren't machine-dependent. */

void
core_file_command (filename, from_tty)
     char *filename;
     int from_tty;
{
  int val;
  extern char registers[];

  /* Discard all vestiges of any previous core file
     and mark data and stack spaces as empty.  */

  if (corefile)
    free (corefile);
  corefile = 0;

  if (corechan >= 0)
    close (corechan);
  corechan = -1;

  data_start = 0;
  data_end = 0;
  stack_start = STACK_END_ADDR;
  stack_end = STACK_END_ADDR;

  /* Now, if a new core file was specified, open it and digest it.  */

  if (filename)
    {
      filename = tilde_expand (filename);
      make_cleanup (free, filename);
      
      if (have_inferior_p ())
	error ("To look at a core file, you must kill the inferior with \"kill\".");
      corechan = open (filename, O_RDONLY, 0);
      if (corechan < 0)
	perror_with_name (filename);
      /* 4.2-style (and perhaps also sysV-style) core dump file.  */
      {
	struct user u;
	int reg_offset;

	val = myread (corechan, &u, sizeof u);
	if (val < 0)
	  perror_with_name (filename);
	data_start = exec_data_start;

	data_end = data_start + NBPG * u.u_dsize;
	stack_start = stack_end - NBPG * u.u_ssize;
	data_offset = NBPG * UPAGES;
	stack_offset = NBPG * (UPAGES + u.u_dsize);
	reg_offset = (int) u.u_ar0 - KERNEL_U_ADDR;

	/* I don't know where to find this info.
	   So, for now, mark it as not available.  */
	core_aouthdr.a_magic = 0;

	/* Read the register values out of the core file and store
	   them where `read_register' will find them.  */

	{
	  register int regno;

	  for (regno = 0; regno < NUM_REGS; regno++)
	    {
	      char buf[MAX_REGISTER_RAW_SIZE];

	      val = lseek (corechan, register_addr (regno, reg_offset), 0);
	      if (val < 0)
		perror_with_name (filename);

 	      val = myread (corechan, buf, sizeof buf);
	      if (val < 0)
		perror_with_name (filename);
	      supply_register (regno, buf);
	    }
	}
      }
      if (filename[0] == '/')
	corefile = savestring (filename, strlen (filename));
      else
	{
	  corefile = concat (current_directory, "/", filename);
	}

      set_current_frame ( create_new_frame (read_register (FP_REGNUM),
					    read_pc ()));
      select_frame (get_current_frame (), 0);
      validate_files ();
    }
  else if (from_tty)
    printf ("No core file now.\n");
}